Since its launch on July 23, 1999, the Chandra X-ray
Observatory has been NASA’s flagship mission for X-ray astronomy, taking its place in the fleet of “Great Observatories.”
Who we are
NASA’s Chandra X-ray Observatory is a telescope specially designed to detect X-ray emission from very hot regions of the Universe such as exploded stars, clusters of galaxies, and matter around black holes. Because X-rays are absorbed by Earth’s atmosphere, Chandra must orbit above it, up to an altitude of 139,000 km (86,500 mi) in space. The Smithsonian’s Astrophysical Observatory in Cambridge, MA, hosts the Chandra X-ray Center which operates the satellite, processes the data, and distributes it to scientists around the world for analysis. The Center maintains an extensive public web site about the science results and an education program.
What we do
Chandra carries four very sensitive mirrors nested inside each other. The energetic X-rays strike the insides of the hollow shells and are focussed onto electronic detectors at the end of the 9.2- m (30-ft.) optical bench. Depending on which detector is used, very detailed images or spectra of the cosmic source can be made and analyzed.
What we are excited about
Chandra has imaged the spectacular, glowing remains of exploded stars, and taken spectra showing the dispersal of elements. Chandra has observed the region around the supermassive black hole in the center of our Milky Way, and found black holes across the Universe. Chandra has traced the separation of dark matter from normal matter in the collision of galaxies in a cluster and is contributing to both dark matter and dark energy studies. As its mission continues, Chandra will continue to discover startling new science about our high-energy Universe.
SN 1979C, a supernova in the galaxy M100, may be the youngest black hole in the so-called local Universe.
Astronomers have seen many gamma-ray bursts, which are likely the births of young black holes, but these are much more distant.
If SN 1979C does indeed contain a black hole, it will give astronomers a chance to learn more about which stars make black holes and which create neutron stars.
SN 1979C was first reported by an amateur astronomer, and some 25 years later space-based telescopes picked up the case.
This composite image shows a supernova within the galaxy M100 that may contain the youngest known black hole in our cosmic neighborhood. In this image, Chandra’s X-rays are colored gold, while optical data from ESO’s Very Large Telescope are shown in yellow-white and blue, and infrared data from Spitzer are red. The location of the supernova, known as SN 1979C, is labeled (roll your mouse over the image above to view the labeled image).
SN 1979C was first reported to be seen by an amateur astronomer in 1979. The galaxy M100 is located in the Virgo Cluster about 50 million light years from Earth. This approximately 30-year age, plus its relatively close distance, makes SN 1979C the nearest example where the birth of a black hole has been observed, if the interpretation by the scientists is correct.
Data from Chandra, as well as NASA’s Swift, the European Space Agency’s XMM-Newton and the German ROSAT observatory revealed a bright source of X-rays that has remained steady for the 12 years from 1995 to 2007 over which it has been observed. This behavior and the X-ray spectrum, or distribution of X-rays with energy, support the idea that the object in SN 1979C is a black hole being fed either by material falling back into the black hole after the supernova, or from a binary companion.
The scientists think that SN 1979C formed when a star about 20 times more massive than the Sun collapsed. It was a particular type of supernova where the exploded star had ejected some, but not all of its outer, hydrogen-rich envelope before the explosion, so it is unlikely to have been associated with a gamma-ray burst (GRB). Supernovas have sometimes been associated with GRBs, but only where the exploded star had completely lost its hydrogen envelope. Since most black holes should form when the core of a star collapses and a gamma-ray burst is not produced, this may be the first time that the common way of making a black hole has been observed.
The very young age of about 30 years for the black hole is the observed value, that is the age of the remnant as it appears in the image. Astronomers quote ages in this way because of the observational nature of their field, where their knowledge of the Universe is based almost entirely on the electromagnetic radiation received by telescopes.
Fast Facts for SN 1979C:
X-ray: NASA/CXC/SAO/D.Patnaude et al, Optical: ESO/VLT, Infrared: NASA/JPL/Caltech
Image is 5 by 4 arcmin, (72,000 x 58,000 light years)
Arp 147 contains a spiral galaxy (right) that collided with an elliptical galaxy (left), triggering a wave of star formation.
Many of these newly-born massive stars raced through their lives and ended with supernova explosions, some as black holes.
A ring of these black holes can be seen in the Chandra data (pink) around the spiral galaxy.
Just in time for Valentine’s Day comes a new image of a ring — not of jewels — but of black holes. This composite image of Arp 147, a pair of interacting galaxies located about 430 million light years from Earth, shows X-rays from the NASA’s Chandra X-ray Observatory (pink) and optical data from the Hubble Space Telescope (red, green, blue) produced by the Space Telescope Science Institute (STScI) in Baltimore, Md.
Arp 147 contains the remnant of a spiral galaxy (right) that collided with the elliptical galaxy on the left. This collision has produced an expanding wave of star formation that shows up as a blue ring containing in abundance of massive young stars. These stars race through their evolution in a few million years or less and explode as supernovas, leaving behind neutron stars and black holes.
A fraction of the neutron stars and black holes will have companion stars, and may become bright X-ray sources as they pull in matter from their companions. The nine X-ray sources scattered around the ring in Arp 147 are so bright that they must be black holes, with masses that are likely ten to twenty times that of the Sun.
An X-ray source is also detected in the nucleus of the red galaxy on the left and may be powered by a poorly-fed supermassive black hole. This source is not obvious in the composite image but can easily be seen in the X-ray image. Other objects unrelated to Arp 147 are also visible: a foreground star in the lower left of the image and a background quasar as the pink source above and to the left of the red galaxy.
Infrared observations with NASA’s Spitzer Space Telescope and ultraviolet observations with NASA’s Galaxy Evolution Explorer (GALEX) have allowed estimates of the rate of star formation in the ring. These estimates, combined with the use of models for the evolution of binary stars have allowed the authors to conclude that the most intense star formation may have ended some 15 million years ago, in Earth’s time frame.
These results were published in the October 1st, 2010 issue of The Astrophysical Journal. The authors were Saul Rappaport and Alan Levine from the Massachusetts Institute of Technology, David Pooley from Eureka Scientific and Benjamin Steinhorn, also from MIT.
Fast Facts for Arp 147:
X-ray: NASA/CXC/MIT/S.Rappaport et al, Optical: NASA/STScI
Image is 54 arcsec across. (about 115,000 light years across)
Evidence for a bizarre state of matter – known as a superfluid – has been found in Cassiopeia A.
Cassiopeia A (Cas A for short) is a supernova remnant located about 11,000 light years away from Earth.
Chandra observations taken over a decade show significant cooling in the dense core left behind after the explosion.
This composite image shows a beautiful X-ray and optical view of Cassiopeia A (Cas A), a supernova remnant located in our Galaxy about 11,000 light years away. These are the remains of a massive star that exploded about 330 years ago, as measured in Earth’s time frame. X-rays from Chandra are shown in red, green and blue along with optical data from Hubble in gold.
At the center of the image is a neutron star, an ultra-dense star created by the supernova. Ten years of observations with Chandra have revealed a 4% decline in the temperature of this neutron star, an unexpectedly rapid cooling. Two new papers by independent research teams show that this cooling is likely caused by a neutron superfluid forming in its central regions, the first direct evidence for this bizarre state of matter in the core of a neutron star.
The inset shows an artist’s impression of the neutron star at the center of Cas A. The different colored layers in the cutout region show the crust (orange), the core (red), where densities are much higher, and the part of the core where the neutrons are thought to be in a superfluid state (inner red ball). The blue rays emanating from the center of the star represent the copious numbers of neutrinos — nearly massless, weakly interacting particles — that are created as the core temperature falls below a critical level and a neutron superfluid is formed, a process that began about 100 years ago as observed from Earth. These neutrinos escape from the star, taking energy with them and causing the star to cool much more rapidly.
This new research has allowed the teams to place the first observational constraints on a range of properties of superfluid material in neutron stars. The critical temperature was constrained to between one half a billion to just under a billion degrees Celsius. A wide region of the neutron star is expected to be forming a neutron superfluid as observed now, and to fully explain the rapid cooling, the protons in the neutron star must have formed a superfluid even earlier after the explosion. Because they are charged particles, the protons also form a superconductor.
Using a model that has been constrained by the Chandra observations, the future behavior of the neutron star has been predicted. The rapid cooling is expected to continue for a few decades and then it should slow down.
Fast Facts for Cassiopeia A:
X-ray: NASA/CXC/UNAM/Ioffe/D.Page,P.Shternin et al; Optical: NASA/STScI; Illustration: NASA/CXC/M.Weiss
Image is 8.91 arcmin across (about 26 light years)
Aceasta imagine a Nebuloasei Helix ne arata o stea muribunda, fiind surprinsa tranzitia spre o pitica alba. Inelele colorate reprezinta gazele expulzate in in perioada de tranzitie, ca si cum si-ar da ultima suflare. Vederea acestei stele apropiata ca masa de soarele nostu, ne ofera un indiciu, despre cum ar putea soarele nostru sa arate intr-o buna zi, atunci cand va fi aproape de sfarsitul vietii sale. Sistemul se afla la aproximativ 650 ani-lumina in constelatia Varsatorului.
Imagine: NASA, WIYN, NOAO, ESA, Hubble Helix Nebula Team, M. Meixner (STScI), & T. A. Rector (NRAO)
O pitica alba numita G29-38 pare ca mananca cometele orbitand in jurul ei, aparent lasand in urma doar un nor de praf, ramasite care au fost detectate de Spitzer Space Telescope al NASA. Descoperirea ofera prima dovada observationala a faptului ca unele comete ar putea trai mai mult de cat sorii lor. Oamenii de stiinta cred ca G29-38 a murit devenind o pitica alba acum 500 milioane de ani, inghitindu-si planetele interioare. Cometele, totusi, orbitand mult in afara zonei interioare, pot supravietui. Praful identificat de Spitzer, a fost creat atunci cand o cometa a fost prinsa in zona interioara a sistemului, si a fost pur si simplu pulverizata de fortele gravitationale imense.
Un alt sistem binar cu comportament ciudat, numit AE Aquarii, este compus dintr-o stea normala si o pitica alba. Mult mai mica si mai densa, pitica alba pare ca absoarbe materie din companioana sa mai mare. In timp ce acest lucru, in mod normal, ar determina pitica alba sa acumuleze masa, i acest caz pare sa arunce cu putere materia in loc s-o acumuleze. Astronomii considera ca, datorita vitezei mari de rotatie si a unui camp electromagnetic foarte puternic, sunt elementele ce stau in spatele acestui comportament ciudat, determinand steau sa arunce un flux de materie care emite un spectru larg de radiatie, vizibila chiar daca este aflata la 330 ani-lumina, in celalalt capat al galaxiei.
Stralucitoarea stea albastra care adomina aceasta fotografie nu este o pitica alba,dar punctul acela mult mai salb in intensitate din partea stanga jos cu sigurana este. Cele doua stele sunt numite Sirius A si respectiv Sirius B si formeaza un sistem binar. Sirius B, este cea mai apropiata pitica alba de Pamant, la aproape 8.6 ani-lumina, ea prezinta o irezistibila oportunitate pentru crecetare, cat timp astronomii pot separa lumina ei de ce a companioanei sale mult mai stralucitoare. Sirius B este mai mica de cat Pamantul, dar avand o masa de multe ori mai mare, care-i confera un camp gravitational 350,000 de ori mai puternic de cat cel al planetei noastre. Daca o persoana de 70 kilograme ar sta pe Sirius B ar cantari 158 milioane Kg.
Imagine: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester)