GAMMA RAY BURSTS

GAMMA RAY BURSTS ARE AMONG THE MOST DISTANT OBJECTS IN THE UNIVERSE...

Gamma-ray bursts (GRBs) are flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies. They are the most luminous electromagnetic events known to occur in the universe. Bursts can last from ten milliseconds to several minutes, although a typical burst lasts 20–40 seconds. The initial burst is usually followed by a longer-lived «afterglow» emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, microwave and radio).
Most observed GRBs are believed to consist of a narrow beam of intense radiation released during a supernova event, as a rapidly rotating, high-mass star collapses to form a neutron star, quark star, or black hole.

The collapse of a massive star into a black hole liberates huge amounts of gravitational energy. In the resulting explosion, matter is accelerated to near the speed of light in a tightly focused jet. This extraordinary energy, and the focused, relativistically boosted emission from the jet allows us to see these explosions, called cosmic gamma-ray bursts (GRBs for short) across much of the observable universe.
GRB ARE FULL OF OPPORTUNITIES TO STUDY THE EXTREMES OF RELATIVITY!
What makes a GRB so much more violent and powerful than, for example, a supernova? GRB are different because they accelerate a giant stream of material in a relativistic jet. Gamma-ray emission measurements indicate that jet particle energy is boosted by thousands of times — a value called the Lorentz factor. This relativistic boost factor is so high, it is problematic for theory. We need to study these jets more to see if we have this right, or develop a better theory. At the very heart of the GRB, deep inside the explosion, is the ultimate power of this great cosmic explosion — a black hole formed in the explosion.
Can we see signatures of a black hole? Is black hole formation the same in a GRB in the distant universe as in the more nearby universe?

Fig. 1. Gravitational waves are created from merging supermassive black holes and binary compact objects. Gravitational waves are expected to be detected by ground and space-based systems in the next decade. The Moon offers another stable platform on which to place detection instruments. Source: NASA

2. The first 60 second of Gamma-Ray Bursts.

Fig. 2. The Extragalactic Gamma-ray background might encrypt in itself the signature of some of the most powerful and exotic phenomena in the Universe.

THE OPTICAL RISE OF GRB — A NEW FRONTIER!
Optical telescopes coupled to X/gamma cameras have caused a revolution in GRB science starting with the first identified GRB around 15 years ago. Current GRB space observatories can respond to a gamma-ray trigger in less than a minute — but that’s far too slow to see the direct, unobscured emission from the jet in the optical. Only a small number of GRB observations include measurements of this early phase of GRB emission. This early optical emission allows us to independently measure the jet acceleration (see above — check the picture ), test ideas of GRB as standard cosmological indicators, see dust evaporate around individual stars to high redshift, compare physics of the emission in the gamma to that of the optical, and much, much more.
This exciting variety of optical rise science is the reason the ExUL has set it’s sights on a space-borne observatory to measure the rise phase of GRB emission throughout the IR and optical, our ultra-fast response GRB satellite program.

Fig. 3. By observing massive stars of Cygnus X area of the milky way, the Large Area Telescope from Fermi spatial gamma observatory has captured emission of young cosmic rays.

3. The Nature of Short-Type Gamma-Ray Bursts.

Fig. 4. On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box. Cygnus X-1 is located near large active regions of star formation in the Milky Way, as seen in this image that spans some 700 light years across. An artist’s illustration on the right depicts what astronomers think is happening within the Cygnus X-1 system. Cygnus X-1 is a so-called stellar-mass black hole, a class of black holes that comes from the collapse of a massive star. The black hole pulls material from a massive, blue companion star toward it. This material forms a disk (shown in red and orange) that rotates around the black hole before falling into it or being redirected away from the black hole in the form of powerful jets. (ref: Chandra)

SHORT GAMMA-RAY BURSTS, THE KEY TO THE COMING ERA OF GRAVITATIONAL WAVE ASTRONOMY!
Soon the next generation of gravitational wave (GW) observatories will come on line, and the most likely first target they will see will be the Short-type gamma ray burst (SGRB). Like the first bodies discovered with optical telescopes, the first GW astrophysical sources will surely change our views of astrophysics and gravity physics, excitement without bounds for anyone who cares what’s «out there» in our universe. SGRB are believed to be pairs of neutron stars in their death throes. We have seen these systems loose energy, by watching their orbits slow down just as predicted by Einstein, and so infer the GW signal.
What we have not seen, is the great, enormous, huge GW signal that occurs at the moment of death: when the two neutron stars — objects weighing as much as our star but so compacted by gravity they are smaller than a city — finally spiral into each other in a titanic explosion that results in the rapid, gamma-ray rich explosion of the SGRB. Like cosmic sirens warning of the cataclysm in progress, the GW signal will come to GW observatory. Like a blind man, however, the GW observatory can only «hear» the very crude, rough direction to the event — it is up to our space-born rapid observatory to see all the optical, IR, X, and gamma light form the explosion, and pinpoint the galaxy, system, and progenitor that will tell us the origin — still a mystery — of these events.
Now, we will have electromagnetic signals from low to high energy, to cross correlate and examine with gravity signals all at the same time. Physics will never be the same with such richness of data from these multiple «messengers» from the cosmos.

Fig. 5. Like wine in a glass, vast clouds of hot gas are sloshing back and forth in Abell 2052, a galaxy cluster located about 480 million light years from Earth. X-ray data (blue) from NASA’s Chandra X-ray Observatory shows the hot gas in this dynamic system, and optical data (gold) from the Very Large Telescope shows the galaxies. The hot, X-ray bright gas has an average temperature of about 30 million degrees.

4. Measuring the Polarization of Gamma-Ray Bursts.

GAMMA-RAY POLARIMETERS WILL TAKE US FROM SPECULATION TO UNDERSTANDING!
The most basic emission mechanism making all this emission from GRBs is thought to be synchrotron emission, energetic emission spiraling around magnetic field lines. So far, the confirmation of this mechanism, the basis of all theory, is elusive. Synchroton emission comes from energetic electroncs spiraling around magnetic field lines; a basic characteristic if this type of emission is that it is polarized. Therefore, measurement of the polarization of this emission should make for, finally, an easy confirmation of the theory. However, gamma-ray polarimetry is brand new, more difficult, and generally requiring larger instruments than simple gamma-ray measurements.
Here at the EXUL and SINP, we are embarking on exciting projects to improve gamma-ray polarimeter design, building on our heritage with the GROME instrument.

Fig. 6. The newly identified quasar has been designated ULAS J1120+0641. It is not the most distant object seen in the Universe — that record probably goes to gamma-ray burst (GRB), the light from an exploded star. But the quasar is hundreds of times brighter than the GRB, and certainly bright enough to allow scientists to start to probe the object and its surroundings in some detail.

Fig. 7. The most distant black hole known is in the galaxy NGC 300, 6 million light-years away. Discovered in January 2010, the black hole is the first found to lurk outside the «Local Group» of galaxies to which the Milky Way belongs.

 

Enigmatic Explosions from the distant universe

Photons from a gamma ray burst racing towards the Fermi satellite. (Image: NASA/Sonoma State University/Aurore Simonnet )

The Most Luminous Objects in the Universe
Gamma-Ray Bursts (GRBs) are the most powerful explosions in the Universe, and are by far the most luminous sources of light known apart from the Big Bang.
The peak luminosity of GRBs, equivalent to the light from millions of galaxies, means they can be detected across the entire Universe, allowing us to probe the evolution of stars back to before galaxies as we know them had formed. GRBs occur at random on the sky and then fade from view. Their rapid gamma- and X-ray variability indicates a small source size which, together with their huge luminosities and clearly non-thermal spectrum, requires the emitting region to be moving towards us at practically the speed of light. Indeed, GRBs are thought to be powered by ultra-relativistic jets produced by rapid accretion onto a newly formed stellar-mass black hole or a rapidly rotating highly-magnetised neutron star. The prompt gamma-ray emission is thought to originate from dissipation within the original outflow by shocks as shells of material collide, or by magnetic reconnection events.

Illustration of the production of a GRB by a massive collapsing star. http://arxiv.org/abs/astro-ph/0102255

The Highest Energy Emission from GRBs
Recent observations by the Swift and Fermi missions have revealed an even more complex behaviour than previously thought, featuring significant spectral and temporal evolution. As yet, no GRB has been detected at energies >100 GeV due to the limited sensitivity of current instruments and the large distance of these events. However, data from Fermi imply that a good fraction of the brightest GRBs could be detected by CTA in just a few minutes by quickly re-pointing some of the array.
Detecting GRBs in the CTA energy range would greatly enhance our knowledge of the intrinsic spectrum and the particle acceleration mechanism of GRBs. CTA could address the relative importance of of the various proposed emission processes, which divide mainly into leptonic and hadronic processes, and help determine if they are the origin of ultra-high-energy cosmic rays, the highest energy particles known to exist in the present Universe . The speed and the composition of the outflows can also be probed by CTA. They can even serve as beacons for probing cosmic radiation fields in the distant Universe, as well as in testing the accuracy of Einstein’s theory of relativity.
Overall, a large discovery space at high energies is readily accessible to CTA. The combination of GRBs being extreme astrophysical sources and cosmological probes make them prime targets for future high-energy experiments. With its large collecting area, energy range and rapid response, CTA is by far the most powerful and suitable VHE facility for GRB research and will open up a new energy range for their study.
About once a day, something remarkable happens: the sky is lit up by a brilliant flash of energy. For a fleeting few seconds, this mysterious burst - coming from a seemingly random direction, different every time - ranks among the brightest objects in the sky.
Yet no one has ever witnessed such a flash directly: the energy comes almost entirely in the form of gamma rays, which human eyes cannot detect. Even if our eyes were sensitive to this extremely energetic form of radiation, gamma rays cannot penetrate the atmosphere. Only via orbiting satellites do we know of the presence of these mysterious blasts.
These events are known as gamma-ray bursts, or GRBs. They represent the most powerful explosions of energy in the cosmos since the Big Bang itself, corresponding to the equivalent of a thousand Earths vaporized into pure energy in a matter of seconds. One of the most enduring mysteries of the universe since their discovery in the 1960s, only recently have they begun to reveal their secrets.

The faint, distant galaxy in which a gamma-ray burst exploded in 1997 appears as a faint smudge in the center of this image from the Hubble Space Telescope. Even in images from the Hubble, most gamma-ray bursts originate from so far away that the galaxies in which they occur appear blurry and faint.

The narrow twin beams of a gamma-ray burst blasts out of a dying star in this artist's conception, just as the star itself begins to explode in a supernova. Both events were triggered by the collapse of the star's core under its own gravity.

What is a gamma-ray burst?

We define a gamma-ray burst based on its observational properties: an intense flash of gamma rays, lasting anywhere from a fraction of a second to up to a few minutes.
Gamma-ray bursts have a few other common features. We believe them to be beamed - the energy does not escape from the explosion everywhere equally, but is focused into a narrow jet (or more likely, two oppositely-directed jets.) The burst itself is also normally followed by a much longer-lived (but also much fainter) signal, visible at optical and other wavelengths. This so-called "afterglow", discovered only in the 1990s, allows us to pinpoint the origin of the GRB - something not possible from the short-lived gamma-ray signal alone.

Where do gamma-ray bursts come from?

For a long time, it was believed that GRBs must come from within our own Galaxy. It seemed impossible that they could be much more distant: for a gamma-ray burst to have come from a distant galaxy, it would have to be incredibly powerful to explain its observed brightness.
And yet we now know that, except perhaps for a few rare exceptions, most GRBs do indeed come from other galaxies - often from among the most distant galaxies in the known universe! The closest GRB known to date is still over a hundred million light-years away, and most of them come from billions of light years. To outshine our own Galaxy's closest stars in our sky from distances that are literally billions of times further away, stupendous amounts of energy are required.

What makes a gamma-ray burst?

No one knows for sure! Our best theory to date is based upon several observed facts. First, the only way to generate huge quantities is via gravitational collapse, and black holes can be very efficient at turning this energy into explosive power. Second, some of the closest GRBs appear to occur simultaneously with supernovae: explosions of stars at the end of their lives. Finally, almost all GRBs happen in galaxies containing large numbers of very massive stars.
Our conclusion: GRBs happen when an extremely massive star, at the end of its life, runs out of fuel and can no longer support itself. It collapses onto its core, crushing it into a black hole. Matter from the star falls towards the black hole at its center, and before it falls in, some of its energy is focused into powerful jets that pummel out of the north and south poles of the star, making a gamma-ray burst. The rest of the star explodes as a supernova soon afterwards.
Other origins are also possible. For example, some GRBs may be due to two ultra-dense neutron stars smashing into each other; and a small fraction may be magnetic eruptions on neutron stars in very nearby galaxies.

Properties Of Quasars

Because of the great distances to the furthest quasars and the finite velocity of light, we see them and their surrounding space as they existed in the very early universe.


More than 100,000 quasars are known, most from the Sloan Digital Sky Survey. All observed quasar spectra have redshifts between 0.06 and 6.4. Applying Hubble's law to these redshifts, it can be shown that they are between 780 million and 28 billion light-years away. Because of the great distances to the furthest quasars and the finite velocity of light, we see them and their surrounding space as they existed in the very early universe.

Most quasars are known to be farther than three billion light-years away. Although quasars appear faint when viewed from Earth, the fact that they are visible from so far away means that quasars are the most luminous objects in the known universe. The quasar that appears brightest in the sky is 3C 273 in the constellation of Virgo. It has an average apparent magnitude of 12.8 (bright enough to be seen through a small telescope), but it has an absolute magnitude of -26.7. From a distance of about 33 light-years, this object would shine in the sky about as brightly as our sun. This quasar's luminosity is, therefore, about 2 trillion (2 × 1012) times that of our sun, or about 100 times that of the total light of average giant galaxies like our Milky Way.

The hyperluminous quasar APM 08279+5255 was, when discovered in 1998, given an absolute magnitude of -32.2, although high resolution imaging with the Hubble Space Telescope and the 10 m Keck Telescope revealed that this system is gravitationally lensed. A study of the gravitational lensing in this system suggests that it has been magnified by a factor of ~10. It is still substantially more luminous than nearby quasars such as 3C 273.

Quasars were much more common in the early universe. This discovery by Maarten Schmidt in 1967 was early strong evidence against the Steady State cosmology of Fred Hoyle, and in favor of the Big Bang cosmology. Quasars show where massive black holes are growing rapidly (via accretion). These black holes grow in step with the mass of stars in their host galaxy in a way not understood at present. One idea is that the jets, radiation and winds from quasars shut down the formation of new stars in the host galaxy, a process called 'feedback'. The jets that produce strong radio emission in some quasars at the centers of clusters of galaxies are known to have enough power to prevent the hot gas in these clusters from cooling and falling down onto the central galaxy.

Quasars are found to vary in luminosity on a variety of time scales. Some vary in brightness every few months, weeks, days, or hours. This means that quasars generate and emit their energy from a very small region, since each part of the quasar would have to be in contact with other parts on such a time scale to coordinate the luminosity variations. As such, a quasar varying on the time scale of a few weeks cannot be larger than a few light-weeks across. The emission of large amounts of power from a small region requires a power source far more efficient than the nuclear fusion which powers stars. The release of gravitational energy by matter falling towards a massive black hole is the only process known that can produce such high power continuously. (Stellar explosions - Supernovas and gamma-ray bursts - can do so, but only for a few minutes.) Black holes were considered too exotic by some astronomers in the 1960s, and they suggested that the redshifts arose from some other (unknown) process, so that the quasars were not really so distant as the Hubble law implied. This 'redshift controversy' lasted for many years. Many lines of evidence (seeing host galaxies, finding 'intervening' absorption lines, gravitational lensing) now demonstrate that the quasar redshifts are due to the Hubble expansion, and quasars are as powerful as first thought.

Quasars have all the same properties as active galaxies, but are more powerful: Their Radiation is 'nonthermal' (i.e. not due to a black body), and some (~10%) are observed to also have jets and lobes like those of radio galaxies that also carry significant (but poorly known) amounts of energy in the form of high energy (i.e. rapidly moving, close to the speed of light) particles (either electrons and protons or electrons and positrons). Quasars can be detected over the entire observable electromagnetic spectrum including radio, infrared, optical, ultraviolet, X-ray and even gamma rays. Most quasars are brightest in their rest-frame near-ultraviolet (near the 1216 angstrom (121.6 nm) Lyman-alpha emission line of hydrogen), but due to the tremendous redshifts of these sources, that peak luminosity has been observed as far to the red as 9000 angstroms (900 nm or 0.9 µm), in the near infrared. A minority of quasars show strong radio emission, which originates from jets of matter moving close to the speed of light. When looked at down the jet, these appear as a blazar and often have regions that appear to move away from the center faster than the speed of light (superluminal expansion). This is an optical trick due to the properties of special relativity.

Quasar redshifts are measured from the strong spectral lines that dominate their optical and ultraviolet spectra. These lines are brighter than the continuous spectrum, so they are called 'emission' lines. They have widths of several percent of the speed of light, and these widths are due to Doppler shifts due to the high speeds of the gas emitting the lines. Fast motions strongly indicate a large mass. Emission lines of hydrogen (mainly of the Lyman series and Balmer series), Helium, Carbon, Magnesium, Iron and Oxygen are the brightest lines. The atoms emitting these lines range from neutral to highly ionized. (I.e. many of the electrons are stripped off the ion, leaving it highly charged.) This wide range of ionization shows that the gas is highly irradiated by the quasar, not merely hot, and not by stars, which cannot produce such a wide range of ionization

Iron Quasars show strong emission lines resulting from low ionization iron (FeII), such as IRAS 18508-7815.

Most Dangerous Computer Viruses

Computer viruses have a relatively short history, but the damages caused by some of them pushed cyber-experts to opening a new chapter on computer viruses. Some viruses led to serious damages and affected a large number of companies, universities and even governments.

Here are some of the most dangerous computer viruses in history:
Jerusalem - 1987
This is one of the first MS-DOS viruses in history that caused enormous destructions, affecting many countries, universities and companies worldwide. On Friday 13, 1988 the computer virus managed to infect a number of institutions in Europe, America and the Middle East. The name was given to the virus after one of the first places that got "acquainted" with it - the Jerusalem University.
Along with a number of other computer viruses, including "Cascade", "Stoned" and "Vienna" the Jerusalem virus managed to infect thousands of computers and still remain unnoticed. Back then the anti-virus programs were not as advanced as they are today and a lot of users had little knowledge of the existence of computer viruses.
Morris (a.k.a. Internet Worm) - November 1988
This computer virus infected over 6,000 computer systems in the United States, including the famous NASA research Institute, which for some time remained completely paralyzed. Due to erratic code, the worm managed to send millions of copies of itself to different network computers, being able to entirely paralyze all network resources. The damages caused by the Morris computer virus were estimated at $96 millions.
To be able to spread, the computer virus used errors in such operating systems as Unix for VAX and Sun Microsystems. The virus could also pick user passwords.
Solar Sunrise - 1998
A decade later the situation didn't change, in fact it even got worse. Using a computer virus, hackers, in 1998, penetrated and took control of over 500 computer systems that belonged to the army, government and private sector of the United States. The whole situation was dubbed Solar Sunrise after the popular vulnerabilities in computers that run on the operating system called Sun Solaris. Initially it was believed that the attacks were planed by the operatives in Iraq. It was later revealed that the incidents represented the work of two American teenagers from California. After the attacks, the Defense Department took drastic actions to prevent future incidents of this kind.
Melissa - 1999
For the first time computers got acknowledged with Melissa computer virus on March 26, 1999, when the virus shut down the Internet mail system, which got blocked with e-mails infected by the worm. It is worth mentioning that at first Melissa was not meant to cause any harm, but after overloading the servers, it led to serious problems. For the first time it spread in the Usenet discussion group alt.sex. Melissa was hidden within a file called "List.DiC", which featured passwords that served as keys to unlocking 80 pornographic websites. The original form of the virus was sent through e-mail to different users.
Melissa computer virus was developed by David L. Smith in Aberdeen Township, New Jersey. Its name comes from a lap dancer that the programmer got acknowledged with while in Florida. After being caught, the creator of the virus was sentenced to 20 months in federal prison and ordered to pay a fine of $5,000. The arrest was made by a team of representatives from FBI, New Jersey State Police and Monmouth Internet.
Melissa had the ability to multiply on Microsoft Word 97 and Word 2000, as well as on Microsoft Excel 97, 2000 and 2003. In addition, the virus had the ability to mass-mail itself from Microsoft Outlook 97 and Outlook 98.
I Love You - May 2000
Using a similar method as the Melissa, the computer virus dubbed "I Love You" managed to infect millions of computers around the world overnight. Just like Melissa this computer virus sent passwords and usernames, which were stored on the attacked computers, back to the developer of the virus. After authorities traced the virus they found that a young Filipino student was behind the attack. The young man was released due to the fact that the Philippines did not have any law that would prevent hacking and spreading malware. This situation served as one of the premises for creating the European Union's global Cybercrime Treaty.
The Code Red worm - July 2001
This 21st century computer virus managed to penetrate tens of thousands of systems that ran Microsoft Windows NT and Windows 2000 server software. The damages caused by the Code Red computer virus were estimated at $2 billion. Core Red was developed to use the power of all computers it infected against the official website of the White House at a predetermined date. In collaboration with different virus hunters and tech firms, the White House managed to decipher the code of the Code Red virus and stop traffic as the malware started its attacks.
Nimda - 2001
Shortly after the September 11 tragedy this computer virus infected hundreds of thousands of computers worldwide. Nimda was considered to be one of the most complicated viruses, having 5 different methods of infecting computers systems and being able to duplicate itself.

Beast Trojan Horse (2002)

Also Known As: Remote Administration Tool or RAT (Now This is a Type)
First understand what is a Trojan Horse is ? and what it can do ?
Trojan Horse is a standalone malicious software program that does not infects computer completely automatically, until  you execute the virus or infected software program it does nothing but once executed it can make copy of itself in multiple directories and hence makes difficult to be removed, it can steal your secret information by many ways such as keystroke logging or can damage your computer system completely.
And Beast is one of the first Trojan Horse program that has capability of reverse connection, this program was written in Delphi programming language by Tataye in 2002.
It was using the injection method to inject viruses into specific process, commonly “explorer.exe” (Windows Explorer), “iexplore.exe” (Internet Explorer), or “msnmsgr.exe” (MSN Messenger) to steal information and give control to its author of your computer.

Once it connects to its author, they can do the following on your PC:

• Access to File Manager – along with browsing victim’s directories it could upload, download, delete, or execute any file, hence becomes more dangerous.
• Remote Registry Editor
• Get Screenshot of your computer Screen and your Webcam
• Passwords tool capable of recovering any stored passwords in the victim’s computer
• Access over Power Options (e.g. shutdown, reboot, logoff, crash, etc.)
• Also included a Chat client for providing communication between the attacker and the victim
• Other tools such as a Remote IP scanner, live keylogger, offline logs downloader, etc.

SQL Slammer (2003)

Also Known As: Sapphire, Worm.SQL.Helkern, SQLSlammer
Appeared at the starting of the year on 27th January 2003 and very quickly it got the highest rank in the list of most dangerous worms of that year because it was the first fileless worm. SQL Slammer was able to spread by taking advantage of the vulnerability found in the SQL Servers.

According to statistics:
SQL Slammer spread to over 90 percent of all vulnerable hosts in 10 minutes and infected around 359,000 Hosts total and according to London-based market intelligence the worm caused between $950 million and $1.2 billion in lost productivity in its first five days worldwide.

Year 2003 has been one of the Most Destructive year in tech world as it got more than one more dangerous Virus, at the end of the year on 12 August call Blaster, According to Estimate it caused Damaged worth 10 billion dollars and on August 19 worm name Sobig worm has been detected which caused damage of 7 billion dollars and infected over 1 million PCs.

MyDoom (2004)

Also Known As: W32.MyDoom@mm, Novarg, Mimail.R and Shimgapi
First seen on 26th January 2004 and it caused Damage of $38 Billions.
MyDoom is still the current record holder for the fastest-spreading mass mailer worm.
Mydoom is primarily spread via e-mail attachments, it comes in email with subject lines including “Error”, “Mail Delivery System”, “Test” or “Mail Transaction Failed” in different languages, including English and French. The mail contains an attachment that, if executed, resends the worm to e-mail addresses found in local files such as a user’s address book.

Next day on 27th January SCO Group offers a US $250,000 reward for information leading to the arrest of the worm’s creator.

Bandook Rat (2005)

Also Known As: Backdoor.Win32.Bandok.bd, Troj/Bandok-J, Backdoor.Bandook, BDS/Bandok.R.2
A very similar virus as Beast Trojan Horse (2002) but with improved functionality detected first in middle of 2005. Bandook Rat abbreviation for “Bandook Remote Administration Tool” is a backdoor trojan horse that infects Windows NT, 2000, XP, 2003, Vista, Windows 7 Also, Yes that means new variants of this virus is still being released by different authors and hence making it the most destructive virus till date.

Blackworm (2006)

Also Known As: Mywife, Hunchi, I-Worm.Nyxem, Blackmal, Nyxem, Blueworm
Blackworm worm was first virus of 3 found on 20 January, 2006. The worm spreads in e-mails using an external SMTP engine. It sends itself with different subjects, body text and attachment names. The worm also copies itself multiple times to an infected hard drive with similar name as windows files in order to be hidden. Blackworm is designed to corrupt data on infected computers on every 3rd day of each month, in respect to The Day the Music Died. After corrupting the data of the computer it visits a webpage with tracking code, so it can be counted how many Systems has been infected, and over 300,000 unique IPs visited that site.

The most scary thing in this worm is, It can deletes your antivirus programs if they are installed in the same directories as the ones specified in the worm’s code. It can also delete the entries in the Windows Registry belonging to these antivirus programs, so antivirus applications will not be run automatically the next time Windows is started.

The worm also contains one GIF file which is used to make a recipient of infected e-mails think that the message was scanned by Norton Anti-Virus and no infection was found.
But its havoc ended soon and it gone off the records after October 26.

Did you Know: By the time you will finished reading this article 95,000+ new computers has been affected by viruses !
This article is half because -

More long article = More time required to read = More computers are affected.

Downadup - 2009
The latest and most dangerous virus is the "downadup" worm, which was also called "Conficker". The computer security company F-Secure stated that the computer virus has infected 3.5 million computers worldwide. This malicious program was able to spread using a patched Windows flaw. Downadup was so "successful" in spreading across the Web, because it used a flaw that Microsoft patched in October in order to distantly compromise computers that ran unpatched versions of Microsoft's operating system. But the greatest power of the worm is believed to be the ability of computers, infected with the worm, to download destructive code from a random drop point. F-Secure stated that three of the most affected countries were China, Brazil and Russia.

VIRUS Cruising Blog : BEWARE - WW4.SAFE VOCHECKER

#Russia #VIRUS Cruising Blog : BEWARE - WW4.SAFE VOCHECKER

This blog is cruising ALL of my blogs 7/24 - IF by chance they are cruising your webpage do NOT click on to see who they are it is a RUSSIAN TROJAN PORN SITE.

My favorite Shakespearian Quotes

 Juliet:

"What's in a name? That which we call a rose

By any other name would smell as sweet."

Macbeth:
To-morrow, and to-morrow, and to-morrow,
Creeps in this petty pace from day to day,
To the last syllable of recorded time;
And all our yesterdays have lighted fools
The way to dusty death. Out, out, brief candle!
Life's but a walking shadow, a poor player,
That struts and frets his hour upon the stage,
And then is heard no more. It is a tale
Told by an idiot, full of sound and fury,
Signifying nothing.

Jaques:
All the world's a stage,
And all the men and women merely players;
They have their exits and their entrances,
And one man in his time plays many parts,
His acts being seven ages.
As You Like It Act 2, scene 7, 139–143

Hamlet:
To be, or not to be, that is the question:
Whether 'tis nobler in the mind to suffer
The slings and arrows of outrageous fortune,
Or to take arms against a sea of troubles
And by opposing end them. To die—to sleep,
No more; and by a sleep to say we end
The heart-ache and the thousand natural shocks
That flesh is heir to: 'tis a consummation
Devoutly to be wish'd. To die, to sleep;
To sleep, perchance to dream—ay, there's the rub:
For in that sleep of death what dreams may come,
When we have shuffled off this mortal coil,
Must give us pause—there's the respect
That makes calamity of so long life.
For who would bear the whips and scorns of time,
Th'oppressor's wrong, the proud man's contumely,
The pangs of dispriz'd love, the law's delay,
The insolence of office, and the spurns
That patient merit of th'unworthy takes,
When he himself might his quietus make
With a bare bodkin? Who would fardels bear,
To grunt and sweat under a weary life,
But that the dread of something after death,
The undiscovere'd country, from whose bourn
No traveller returns, puzzles the will,
And makes us rather bear those ills we have
Than fly to others that we know not of?
Thus conscience does make cowards of us all,
And thus the native hue of resolution
Is sicklied o'er with the pale cast of thought,
And enterprises of great pitch and moment
With this regard their currents turn awry
And lose the name of action.
Hamlet Act 3, scene 1, 55–87

Duke Orsino:
If music be the food of love, play on,
Give me excess of it; that surfeiting,
The appetite may sicken, and so die.
Twelfth Night Act 1, scene 1, 1–3

Hamlet:
Swear by my sword
Never to speak of this that you have heard.
Ghost:
[Beneath] Swear by his sword.
Hamlet:
Well said, old mole, canst work i' th' earth so fast?
A worthy pioner! Once more remove, good friends.
Horatio:
O day and night, but this is wondrous strange!
Hamlet:
And therefore as a stranger give it welcome.
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
Hamlet Act 1, scene 5, 159–167

Player Queen:
Both here and hence pursue me lasting strife,
If once I be a widow, ever I be a wife!
Player King:
'Tis deeply sworn. Sweet, leave me here a while,
My spirits grow dull, and fain I would beguile
The tedious day with sleep.
Player Queen:
Sleep rock thy brain,
And never come mischance between us twain!
Hamlet:
Madam, how like you this play?
Queen:
The lady doth protest too much, methinks.
Hamlet Act 3, scene 2, 222–230

Hamlet:
"To sleep, perchance to dream-
ay, there's the rub."
Hamlet (III, i, 65-68)

Juliet:
O Romeo, Romeo, wherefore art thou Romeo?
Deny thy father and refuse thy name;
Or if thou wilt not, be but sworn my love
And I'll no longer be a Capulet.
Romeo:
[Aside] Shall I hear more, or shall I speak at this?
Juliet:
'Tis but thy name that is my enemy:
Thou art thyself, though not a Montague.
What's Montague? It is nor hand nor foot,
Nor arm nor face, nor any other part
Belonging to a man. O be some other name!
What's in a name? That which we call a rose
By any other word would smell as sweet;
So Romeo would, were he not Romeo call'd,
Retain that dear perfection which he owes
Without that title. Romeo, doff thy name,
and for thy name, which is no part of thee,
Take all myself.
Romeo And Juliet Act 2, scene 2, 33–49

Prospero:
Our revels now are ended. These our actors,
As I foretold you, were all spirits, and
Are melted into air, into thin air:
And like the baseless fabric of this vision,
The cloud-capp'd tow'rs, the gorgeous palaces,
The solemn temples, the great globe itself,
Yea, all which it inherit, shall dissolve,
And, like this insubstantial pageant faded,
Leave not a rack behind. We are such stuff
As dreams are made on; and our little life
Is rounded with a sleep.
The Tempest Act 4, scene 1, 148–158

Juliet:
'Tis almost morning, I would have thee gone—
And yet no farther than a wan-ton's bird,
That lets it hop a little from his hand,
Like a poor prisoner in his twisted gyves,
And with a silken thread plucks it back again,
So loving-jealous of his liberty.
Romeo:
I would I were thy bird.
Juliet:
Sweet, so would I,
Yet I should kill thee with much cherishing.
Good night, good night! Parting is such sweet sorrow,
That I shall say good night till it be morrow. [Exit above]
Romeo And Juliet Act 2, scene 2, 176–185

Hamlet:
What a piece of work is a man, how noble in reason, how
infinite in faculties, in form and moving how express and
admirable, in action how like an angel, in apprehension how like
a god! the beauty of the world, the paragon of animals—and yet,
to me, what is this quintessence of dust? Man delights not me—
nor woman neither, though by your smiling you seem to say so.
Rosencrantz:
My lord, there was no such stuff in my thoughts.
Hamlet Act 2, scene 2, 303–312

Richard:
Now is the winter of our discontent
Made glorious summer by this son of York;
And all the clouds that low'r'd upon our house
In the deep bosom of the ocean buried.
Richard The Third Act 1, scene 1, 1–4

"Love looks not with the eyes but with the mind."
A Midsummer Night's Dream (I, i, 234)

Doctor:
What is it she does now? Look how she rubs her hands.
Gentlewoman:
It is an accustom'd action with her, to seem thus
washing her hands. I have known her continue in this a quarter of
an hour.
Lady Macbeth:
Yet here's a spot.
Doctor:
Hark, she speaks. I will set down what comes from her, to
satisfy my remembrance the more strongly.
Lady Macbeth:
Out, damn'd spot! out, I say!—One; two: why, then
'tis time to do't.—Hell is murky.—Fie, my lord, fie, a soldier, and
afeard? What need we fear who knows it, when none can call our
pow'r to accompt?—Yet who would have thought the old man to
have had so much blood in him?
Macbeth Act 5, scene 1, 26–4
Horatio:
He waxes desperate with imagination.
Marcellus:
Let's follow. 'Tis not fit thus to obey him.
Horatio:
Have after. To what issue will this come?
Marcellus:
Something is rotten in the state of Denmark.
Horatio:
Heaven will direct it.
Marcellus:
Nay, let's follow him. [Exeunt.]
Hamlet Act 1, scene 4, 87–9

Hamlet:
Heaven and earth,
Must I remember? Why, she would hang on him
As if increase of appetite had grown
By what it fed on, and yet, within a month—
Let me not think on't—Frailty, thy name is woman!—
Hamlet Act 1, scene 2, 142–146

Romeo:
But soft, what light through yonder window breaks?
It is the east, and Juliet is the sun.
Arise, fair sun, and kill the envious moon,
Who is already sick and pale with grief
That thou, her maid, art far more fair than she.
Romeo And Juliet Act 2, scene 2, 2–6

Caesar:
"Cowards die many times before their deaths,
The valiant never taste of death but once."
Julius Caesar (II, ii, 32-37)

King:
"My words fly up, my thoughts remain below: Words without thoughts never to heaven go."
Hamlet (III, iii, 100-103)

Lysander:
Ay me! for aught that I could ever read,
Could ever hear by tale or history,
The course of true love never did run smooth;
But either it was different in blood—
Hermia:
O cross! too high to be enthrall'd to low.
Lysander:
Or else misgraffèd in respect of years—
Hermia:
O spite! too old to be engag'd to young.
Lysander:
Or else it stood upon the choice of friends—
Hermia:
O hell! to choose love by another's eyes.
A Midsummer Night's Dream Act 1, scene 1, 132–140

Lear:
"Nothing can come of nothing: speak again."
King Lear (I, i, 92)

Portia:
You stand within his danger, do you not?
Antonio:
Ay, so he says.
Portia:
Do you confess the bond?
Antonio:
I do.
Portia:
Then must the Jew be merciful.
Shylock:
On what compulsion must I? tell me that.
Portia:
The quality of mercy is not strain'd,
It droppeth as the gentle rain from heaven
Upon the place beneath. It is twice blest:
It blesseth him that gives and him that takes.
The Merchant Of Venice Act 4, scene 1, 180–187

Amiens:
"Blow, blow, thou winter wind,
Thou art not so unkind
As man's ingratitude;"
As You Like It (II, vii, 174-176)

Juliet:
Go ask his name.—If he be married,
My grave is like to be my wedding-bed.
Nurse:
His name is Romeo, and a Montague,
The only son of your great enemy.
Juliet:
My only love sprung from my only hate!
Too early seen unknown, and known too late!
Prodigious birth of love it is to me
That I must love a loathèd enemy.
Romeo And Juliet Act 1, scene 5, 134–141

 Helena:
"We should be woo'd and were not made to woo."

A Midsummer Night's Dream (II, i, 242)

Can GRBs usher in a DoomsDay?

The persistence of life on Earth may depend on massive explosions on the other side of the galaxy, according to a new theory that suggests powerful bursts of space radiation could have played a part in some of our planet's major extinction events.

The explosions — gamma-ray bursts thought to occur when two stars collide — can  release tons of high-energy gamma-ray radiation into space. The researchers found that such blasts could be contributing to the depletion of the Earth's ozone layer. Disruption of the ozone layer lets ultraviolet light filter down to the surface of the Earth, where it can change organisms by mutating their genes.
Now, researchers are beginning to connect the timing of these gamma-ray bursts to extinctions on Earth that can be dated through the fossil record.
"We find that a kind of gamma-ray burst — a short gamma-ray burst — is probably more significant than a longer gamma-ray burst," study researcher Brian Thomas of Washburn University, in Topeka, Kan., said in a statement. "The duration is not as important as the amount of radiation."
The research will be presented Sunday at the Geological Society of America's annual meeting in Minneapolis.
Bursting out Gamma-ray bursts come in two flavors: a longer, brighter burst and a "short-hard" burst, which lasts less than a second but seems to give off more radiation than a longer burst.
If such a burst were to happen inside the Milky Way, its effects on Earth would be much longer lasting. These bursts of radiation reach the Earth's atmosphere and cause free oxygen and nitrogen atoms to bang together, and some recombine into ozone-destroying compounds called nitrous oxides. Nitrous oxides in the atmosphere are long-lived; they keep destroying ozone until they fall out of the sky in rain drops.

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The short bursts may be caused by fender-benders between stars, such as dense neutron stars or black holes colliding. The researchers were able to estimate that such stellar collisions probably happen about once every 100 million years in any given galaxy. At this rate, Earth would have been hit by several of these short-hard events over the course of its 4.5-billion-year history.
Life on Earth Destruction of the ozone layer can have many effects on life on our planet. Radiation blasts on the world's plants and animals could wreak havoc on Earth's food webs and possibly lead to planetwide extinction events
Improved and accumulated data collected by NASA's SWIFT satellite, which catches gamma-ray bursts in action in other galaxies, is providing a better case for the power and threat of the short bursts to life on Earth. Researchers are also looking for evidence of past bursts, including special elements that are  created only during radiation events hitting Earth, such as a heavy version of iron.
Thomas is now working with paleontologists to correlate levels of this heavy iron with evidence of extinction events in the fossil records.
"I work with some paleontologists, and we try to look for correlations with extinctions, but they are skeptical," Thomas said. "So if you go and give a talk to paleontologists, they are not quite into it. But to astrophysicists, it seems pretty plausible."
 According to their newest models, gamma radiation from a nearby burst would quickly deplete much of Earth's protective ozone layer, allowing increased ultraviolet radiation (UV) from the sun to reach the surface.
In the longer term, chemical reactions in the atmosphere would produce dark, nitrogen-based gases that would block the sun's heat and trigger global cooling, even as the gamma rays continued to deplete ozone and let in UV rays, the authors suggest.
Some of the pollution would fall as damaging acid rain, which can severely disrupt ecosystems.
The atmosphere might be able to recover within a decade, and a rise in DNA damage caused by increased UV exposure might pass after a few months or years, the researchers note.
But other biological impacts—such as reduced ocean productivity—could linger for an unknown length of time, Thomas said.
The Trouble With Trilobites
Bruce Lieberman, a paleontologist at the University of Kansas, helped develop the initial theory about the Ordovician die-off but did not co-author the recent papers.
The prevailing idea is that an ice age caused the extinction event, he said, but he questions the completeness of that hypothesis.
"At other times there have been ice ages without mass extinctions," he said.
Furthermore, the ice age during the Ordovician was comparatively short, lasting only about 500,000 years before the climate cycled back to a warm spell—almost as if something unusual set the icy period in motion.
So far Thomas and Melott have uncovered a pattern of higher UV radiation during the Ordovician extinction that would match cosmic bombardment over the South Pole.
And Lieberman believes the disappearance of trilobites, extinct arthropods related to horseshoe crabs, could be tied to the Ordovician event.
Although most trilobites are mud-scurrying bottom dwellers, the juveniles of some species have a life stage that sends them floating in the shallow water column, making them vulnerable to higher UV radiation.
But like NASA's Thompson, Lieberman adds that worry over a future gamma-ray burst is "not the thing that's keeping me up at night."
Instead he appreciates the new work for pointing out that Earth is a vulnerable part of the cosmos.
"It gives us a new perspective on things like natural selection and adaptation.

How Can U Kiss her Best

There really is a right and wrong way to kiss a woman. If you screw up when you first kiss a woman, you can pretty much count on that ruining any future relationship. Like Hitch stated, a woman bases the relationship on the first kiss, and if you don’t impress when you kiss her…
Let’s get on with how to kiss a woman:
When you go in to kiss a woman, cup her face in both of your hands so that your palms are gently cradling her jaw line and your thumbs are just in front of cheek bones. You can also place your hands further back with your thumbs just in front of her ears if that’s more comfortable for you. This allows you to contour her face and guide it where you want her to go. This helps to avoid the possibility to kiss her too hard and too fast, which is akin to smacking her in the teeth.
In our rush to get the kiss we move too fast, or are unsure of our distance, timing and pressure and suddenly — BANG! Your loving kiss turns into a less than exciting clash of the molars! Take the time to kiss a woman.
When you kiss a woman, deliberately move her face in toward yours. I want you to look her in the eyes and slowly close your eyes as you gently bring her face to yours before the kiss. I want you to touch her lips to yours as lightly as you can and I want you to sense and pay attention to several things when you kiss a woman.
This takes practice to get good at but once you do… She’s yours! Here’s what you PAY ATTENTION when you kiss a woman:

• How much pressure is she using to kiss you?
• Is she pressing her lips hard against yours, soft?
• What kind of force is she exerting with her lips?

Also, notice the configuration of her lips for the kiss:

• Is she a fish kisser?
• Does she open her mouth very wide
• Does she keep her lips close together?
• Pay attention to what she is doing to you!

Kiss a woman gently and allow yourself to feel how she is kisses you. This is key! Don’t focus on kissing her! Focus on how she is kissing you! (Ladies, the same goes for you) This is a concept learned from “Tai Chi Push Hands” called “listening.” Its the ability to sense and interpret subtle changes in pressure and energy through your sense of touch — in this case via your lips.
Here is where “listening” meets “projection” to create her perfect kiss! Here’s how it works:
She already has an internal checklist of what a kiss is supposed to feel like for her. By paying attention to the way she kisses you then kissing her back exactly the same way, you validate her model how things work, demonstrate you are just like her and you perfectly fire off all the signals that tell her mind body and emotions its okay to go to the next level.
In hypnosis we would call this “pacing and leading.” Now Lets Sweeten the Deal a bit…
Once you have matched her particular style of kissing and you’re effectively doing it back to her the same way, you can start to direct her a bit more.
The act of kissing her the way she kisses you dramatically deepens the sense of “connection” and “rapport” she is going to have with you. Continue to pay attention to her responses. Think in terms of simply wanting to give her pleasure and paying attention to her responses when you kiss.
Once you have matched her kissing style you now have a couple of choices:
You can continue to kiss the way she does…
OR
You can slowly begin to alter your method of kissing and see if she responds by following you. When she follows you by changing her way of kissing you now have more freedom to play.

Here Are Ten Signs You Don’t Know How To Kiss A Woman:

10. She french kissed once, but never again
She slipped her tongue on you, but didn’t ever again. It could be that you’re much too eager with the tongue. Two steps forward, one step back.
9. Makes excuses when you go to kiss her
She says, “I have to get up early” or “I need to floss my cat”. You might need to reevaluate this relationship, you might have ruined it. If she’s not making out with you periodically, then you don’t know how to kiss a woman.
8. She’s tired when you want to kiss her
If she’s constantly yawning when you try and lay the smack down, then you need some improvement when you kiss a woman.
7. She wants to get busy with other parts of your body
This isn’t that bad. But you still don’t know how to kiss a woman, try and improve it, so you can complete the intimacy.
6. She never starts kissing you
If she doesn’t initiate, then you did something wrong. No girl no matter how shy, wont want to make out with her lover.
5. She doesn’t give you compliments
If she doesn’t say something like, “you know how to kiss”, or “I’ve never felt like kissing this much” chances are you don’t know how to kiss a woman. (or if she doesn’t make some noises)
4. She suddenly springs up “Let’s be friends” after the first kiss
You need immediate attention. See Double Your Dating.
3. She pops breath mints
If she’s popping breath mints, it could be a good sign for kissing. She might be self-conscious about her breath, or it might be yours. Always come prepared and pop them when you’re about to kiss a woman.
2. If her lips are the signs of Jolies!
Try chewing on them less, and let her lips heal so she doesn’t get some weird disease through an open wound with you.

Neck Kissing

It’s Sensual

Neck is one of the most sensual areas for kissing a girl. It can either be reached on the way down from her lips or vice-versa. If you desire to make your girl feel aroused the right way, the manner of kissing or rather sucking, licking or biting her neck does matter a lot. The results can be totally amazing if she is particularly sensitive towards being touched romantically in the neck region.

Kissing Her Neck

There can be no set rules regarding how to kiss a girl’s neck. But, dancing floor is definitely an interesting place to begin the activity. Begin with sending out clear signals through clearing up her hair from over her neck, breathing on her neck, drawing her closer and closer, rubbing her back, thighs, ass and other accessible places, and so on. You know it that you are hitting the right chord with her when she starts enjoying your touch by keeping her eyes closed, exposing her neck and tilting towards you. Start by laying down pecks or small kisses on her neck and the area around. With the passage of time, as the passion becomes irresistible, start working your way up to her lips and plant a soft and tender kiss over them.
Neck kissing at first might appear to be just another activity while making out but it serves a great deal when it comes to having a real enjoyable experience. After all, love is an eternal feeling and the expression of it should also convey this emotion in the right spirit.

Ultraluminous Infrared Galaxies

Ultraluminous Infrared Galaxies Ultraluminous infrared galaxies (ULIRGs) are galaxies which are about 100 to 1,000 times brighter in the infrared than a typical galaxy like our own Milky Way. They are the most luminous galaxies known in the local universe, and radiate more than ninety percent of their light in the infrared. Most of these galaxies are found in merging and interacting galaxy systems. It is thought that their brightness results from galactic collisions, which increase the rate of star formation. Infrared emission from galaxies comes primarily from three sources: stars, interstellar gas, and dust. The emission from stars peaks in the near infrared (1-3 microns - a micron is short for a micrometer or 0.000001 meters). Emission from atoms and molecules in interstellar gas makes up only a few percent of the infrared output of galaxies. The primary source of infrared radiation beyond 3 microns is thermal emission from dust grains heated by starlight. The brightest infrared galaxies are usually the ones which have a lot of dust (from star-forming regions for example). Astronomers using the IRAS satellite observed 20,000 galaxies in the infrared. Many of these were starburst galaxies - galaxies which are forming enormous numbers of new stars and are thus extremely bright in the infrared. Further infrared studies of these galaxies may find the cause of this star-forming frenzy. At the left is a 2MASS infrared image of a starburst galaxy. Sometimes galaxies, each containing billions of stars, collide with each other. These collisions trigger star formation in these galaxies by causing the compression of clouds of gas and dust to the point where they collapse due to their own gravity. Due to a high rate of star formation, colliding gas-rich galaxies radiate very strongly in the infrared. The ISO satellite observed several colliding galaxies in the infrared and detected many areas of intense star formation within them. Below are nine examples of ultraluminous infrared galaxies. Several of the images show galaxies in collision.   FSC  15307+3253 FSC15307+3253 is an Ultra-Luminous InfraRed Galaxy (ULIRG), with a luminosity between 8 and 1000 µm of approximately 2×1013 L⊙, possibly the largest known at this time. The "FSC" refers to Faint Source Catalogue, one of the source catalogs produced by the IRAS infrared survey mission. The emission is believed due to some combination of starburst activity and accretion onto a super-massive black hole, producing primary radiation at shorter wavelengths which is mostly blocked by obscuring dust, which is in turn heated and re-radiates in the infrared. The redshift of the source is , indicating a distance of the order of 7 billion light years. IRAS 10214+424 has an intrinsic true luminosity of  2×1013 L⊙ and  an Infrared luminosity of  7×1012 L⊙.

How Active They Are?

The most likely reason that clusters of galaxies have more elliptical

than spiral galaxies is that in the high density cluster environment

$a) spirals merge to form ellipticals.

b) intracluster gas strips galaxies of the gas needed for star

formation.

c) near-misses between galaxies makes them rounder.

d) galaxies are older and their brighter disk stars have burned out.

At high redshift, a larger fraction of galaxies are "active" (show

signs of powerful luminous nuclei) than at low redshift. Therefore, we

can safely say that

a) all galaxies go through an active phase,

and more galaxies in the past were active than now.

$b) some galaxies go through an active phase

and more galaxies in the past were active than now.

c) all galaxies are either active or normal.

d) galaxies may become active more than once in their lifetimes.

At high redshift, a larger fraction of galaxies are "active" (show

signs of powerful luminous nuclei) than at low redshift. If galaxies

only become active when they collide or interact with nearby galaxies,

then it might be true that

a) there were more interactions in the past, and activity fades away.

b) the number of distinct galaxies in the Universe decreases with time.

c) galaxies were closer together in the past.

$d) all of the above.

The large doppler velocity widths of broad emission lines in active

galaxies (Seyferts and quasars) could NOT be created by hot

emitting clouds that are

a) swirling at high velocities around a black hole.

b) falling into the neighborhood of a black hole.

c) being ejected into a broad cone or disk-shaped wind.

$d) being ejected along a narrow-angled jet.

Narrow absorption lines in the spectra of distant quasars

could be caused by clouds of gas on the

a) near side of the quasar with large random velocities but small

bulk velocities.

$b) near side of the quasar with small random velocities but large bulk

velocities.

c) far side of the quasar with large random velocities but small

bulk velocities.

d) far side of the quasar with small random velocities but large

bulk velocities.

Seyferts and quasars are both types of active galaxies,

harboring powerful luminous nuclei. Quasar nuclei appear to be more

luminous, and therefore their black holes

a) are accreting matter at a higher rate.

b) are more massive.

c) are less obscured along our sightline.

$d) any of the above.

The word "quasar" comes from "quasi-stellar". What makes quasars

quasi-stellar is that they can have a

a) proper motion seen between images taken at 2 epochs.

b) Doppler velocity shift evident in their spectra.

$c) point-like appearance in an image.

d) binary companion.

The brightest Quasars can have luminosities of up to ~10¹⁵ L_sun.

The wide variety of spectra observed from different active nuclei of

galaxies appear may result from

a) how many neutron stars they contain.

b) the amount of dust in our Galaxy blocking the view.

$c) the angle at which we view each nucleus.

e) whether or not the galaxy has a close companion.

One method you could use to search for a high-mass black hole at the

center of a galaxy is to look for

a) a black dot at the galaxy's nucleus.

b) a very high luminosity star.

$c) a very large range of Doppler shifts around the nucleus.

d) distortion in the shapes of stars near the nucleus.

Rapid variability in the luminous nuclei of quasars is evidence that

the emission region must be

$a) small.

b) large.

c) moving rapidly.

d) exploding.

The powerful nuclei of quasars and Seyfert galaxies cannot be

dominated by starlight because nuclear fusion in a group of stars

could not account for the quasar's observed

a) rapid variability.

b) luminosity.

c) compact size.

$d) all of the above

The distance to the point-like quasars is found from

a) comparing their apparent and absolute magnitude.

b) the apparent magnitudes of their supernovae.

c) their parallax measured with radio telescopes.

$d) their redshift and the Hubble law.

If the large redshifts of quasars were NOT caused by the cosmological

expansion, then bright quasars could possibly be explained as

a) distant objects that are very luminous.

$b) nearby luminous objects exploding outward from the Milky Way.

c) bright nearby objects severely reddened by intervening dust.

d) distant objects severely reddened by intervening dust.

Quasars are more likely powered by accretion onto a supermassive

black hole than by stars because accretion is

a) the only natural way to produce radio and x-ray emission.

$b) a much more efficient means than fusion of extracting energy

from matter.

c) possible in the early universe before stars even formed.

   d) responsible for destroying and engulfing stars.

Seyfert Galaxies

  Seyfert galaxies have been among the most intensively studied objects in astronomy, primarily because they are thought to be nearby, low-luminosity versions of the same phenomenon observed in quasars. A massive black hole in the nucleus of a galaxy, accreting gas from its surrounding environment, is thought to power all these objects. Of course, we do not see the black hole itself, but the UV continuum radiation is generally presumed to be thermal emission from the hot gas that forms an accretion disk surrounding the black hole. In addition, very broad emission lines are observed, which are thought to come from clouds somewhat farther away, moving at velocities of order . These broad-line clouds are photoionized and heated by the extreme-UV radiation from the central source, resulting in the strong, broad resonance line emission observed from hydrogen Lyman-, CIV (1550 Å), and other elements. The permitted lines also sometimes show narrower cores, and there are also narrow forbidden lines, which are thought to arise from more distant, lower density, photoionized gas in a narrow-line region.
The broad-line component dominates the spectra of quasars and type 1 Seyfert galaxies, while the narrow-line component dominates in type 2 Seyferts. It is widely believed that the objects may be basically similar, but that obscuration of the central region as viewed from certain directions may hide the continuum and broad-line regions in type 2 Seyfert galaxies, leaving a clear view of only the narrow-line region. The luminosity of Seyferts is typically , where is the luminosity of the Sun, making the tiny nuclear region as luminous as an entire galaxy of stars, and the inferred mass of the central black hole is to , where is the mass of the Sun. The luminosity is proportional to the mass-accretion rate, which is 1 yr. Small values of these parameters are associated with low-luminosity Seyferts, and large values are thought to characterize the much rarer, high-luminosity quasars.
The far-UV spectral region is of fundamental importance in determining the nature of all these active galactic nuclei. The UV continuum radiation may arise in an accretion disk very close to the black hole, while UV emission and absorption lines provide the best diagnostics of the surrounding material in the broad- and narrow-line regions. Consequently, observations of Seyfert galaxies and quasars were a goal of one of the major observational programs for HUT on Astro-1.
One of the brightest and best-studied Seyfert galaxies is NGC 4151. It has been classified as type 1.5, showing the characteristic features of both types 1 and 2 (Osterbrock & Koski 1976). We obtained a high quality spectrum of NGC 4151 in a 2200 s observation with HUT (Figure 3). Below 1200 Å, a region in which no Seyfert galaxy has previously been observed, we find strong emission in the OVI doublet and a very complex absorption-line spectrum. The Lyman- line and the OVI line are both found to have broad wings with full width at half maximum , identical to the CIV feature, but overlying absorption by numerous lines tends to obscure this fact. Kriss et al. found that the broad lines have relative intensities similar to those seen in quasars (where the large redshift of quasar radiation makes this spectral region accessible to other telescopes) and to theoretical photoionization calculations. All of the permitted lines also have similar cores, with .

 

The strongest absorption lines include the Lyman series of hydrogen, as well as features due to CIII and NIII and higher ionization states, up to NV and OVI. All of the absorption lines are blueshifted, with respect to the galaxy rest frame, by several hundred km s, and they appear to have intrinsic widths of about . The UV continuum disappears completely below 924 Å, owing to strong absorption by overlapping Lyman lines. The ratio of the strengths of the CIII 977 Å line and the 1176 Å line (which arises in an excited state) indicates densities in the absorbing gas greater than . Such high densities are characteristic of the gas in the clouds that yield broad emission lines. Kriss et al. (1993) conclude that the absorption may arise in the disintegrating remnants of outflowing, radiatively accelerated, broad-line clouds. Furthermore, this same material may be responsible for producing the narrow cores of the permitted emission lines. Finally, this material may collimate the ionizing radiation from the central source, explaining the bipolar cone-like appearance of the narrow emission-line region (Kriss et al. 1993). The absorption lines seen by HUT in the far-UV thus provide an important new means for studying conditions in active galactic nuclei.