Chandra resolves cosmic X-ray glow, finds mysterious new sources The Chandra X-ray satellite has resolved most of the X-ray background, a pervasive glow of X-rays throughout the Universe, first discovered in 1962: The telescope sampled a region of the sky about 1/5 the angular area of the full moon and resolved about 80 percent of the more-energetic X-ray background into discrete sources. Stretched across the entire sky, this would account for approximately 70 million sources, most of which would be identified with galaxies. Their analysis confirms that a significant fraction of the X-ray background cannot be due to diffuse radiation from hot, intergalactic gas, as another interpretation of the background had been. Nearly 1/3 of the sources are galaxies whose cores are very bright in X rays yet emit virtually no optical light from the core - these "veiled galactic nuclei" galaxies may number in the tens of millions over the whole sky. Their bright X-ray cores make these galaxies AGNs. Because these numerous AGN are bright in X rays, but optically dim, the Chandra observation implies that optical surveys of AGN are very incomplete. A second new class of objects, comprising approximately 1/3 of the background, is assumed to be "ultra-faint galaxies:" they emit little or no optical light and could have redshifts of up to 6.	Harvard & MSFC Press Releases / SpaceScience.com. Coverage by ABC News, Space.com = ExploreZone, NYT, Science News, Welt. Related discoveries: Supermassive black hole candidates in 3 more elliptical galaxies - are they the "crystal seeds" around which galaxies form? The 3 new cases support an earlier argument that the masses of the central engines are strongly correlated with the overall masses of the galaxies they are in: U. Mich Press Release + Space.com story. 'Mini-Quasar' GRS 1915+105 behaves like a giant particle collider, with massive shock waves generating eruptions every 45 to 90 minutes - "the greatest show-off of all black holes": Cornell Press Release.
Chandra detects faint X-rays from Sgr A* Culminating 25 years of searching by astronomers, a faint X-ray source has been detected by NASA's Chandra X-ray Observatory at the precise spot of Sgr A*, the massive, compact and rather dark central object of our Milky Way that many believe to be a black hole. Sagittarius A* is a long-known point-like, variable radio source at the center of our galaxy: It looks like a faint quasar and is believed to be powered by gaseous matter falling into a supermassive black hole with 2.6 million times the mass of our sun. Chandra's remarkable detection of this X-ray source - that is so close to the correct position that an association with Sgr A* is all but certain - has placed astronomers within a couple of years of a coveted prize: measuring the spectrum of energy produced by Sgr A* to determine in detail how the Galaxy's "central engine" really works. The first surprise is already there: Now that the X-ray source has been isolated, it has taken researchers by surprise by being much fainter than expected. "The luminosity of the X-ray source we have discovered already is a factor of five fainter than previously thought, based on observations from an earlier X-ray satelllite," one of the discoverers said: "This poses a problem for theorists. The galactic center is a crowded place. If we were to find that most or all of the X-ray emission is not from Sagittarius A*, then we will have shown conclusively that all current [black hole based] models from Sagittarius A* need to be rethought from the ground up."	MSFC Press Release and picture. More from Sgr A*: Streamers of ammonia gas towards the Galactic Center have been mapped by radio astronomers, connecting giant clouds of molecular gas to the circum-nuclear disk: CfA Press Release and picture; Space.com story. A related Chandra discovery: A `cool' black hole candidate at the heart of the Andromeda Galaxy - the gas funneling into its core object is unexpectedly cool, though still hot compared to the other 100+ X-ray sources in the galaxy: MSFC Press Release and pictures.
Chandra finds oxygen and neon ring in ashes of exploded star The X-ray observatory has revealed an expanding ring-like structure of oxygen and neon that was hurled into space by the explosion of a massive star: The image of E0102-72 provides unprecedented details about the creation and dispersal of heavy elements necessary to form planets like Earth. E0102-72 is the remnant of a supernova explosion located in the Small Magellanic Cloud. By using the High Energy Transmission Grating Spectrometer (HETG), astronomers were able to pinpoint the distribution of each chemical element individually and measure the velocities of different parts of the expanding ring. They also show the shock wave in a kind of "freeze-frame," revealing the progressive heating of the stellar matter as it plows into the surrounding gas. This is the first time such detailed X-ray information has ever been obtained for a supernova remnant. And by measuring the expansion velocity of the ring one can estimate the amount of energy liberated in the explosion: enough to power the sun for 3 billion years. The ring has more complex structure and motion than can be explained by current simplified theories, suggesting complexity in the explosion itself or in the surrounding interstellar matter.	MSFC Press Release and picture; a Discovery story. Still more Chandra results: The core of the nearest starburst galaxy, Messier 82: Here the CXO has found supernova remnants and X-ray binaries, some of the brightest such objects known. And a diffuse X-ray light in the image extending over several thousand light years is caused by multimillion-degree gas flowing out of M82: MSFC Press Release and pictures. 1000 faint X-ray stars in the Orion Nebula - the richest field of X-ray sources ever obtained in the history of X-ray astronomy: MSFC Press Release and picture.
Three early discoveries by the FUSE satellite launched last June (Update # 137) and now nearing the end of its 'shakedown' period have now been published: They all have nothing to do with the Far Ultraviolet Spectroscopic Explorer's original task of measuring the deuterium abundance in space, but they made use of FUSE's excellent FUV spectrograph that beats every predecessor. By using the light from distant quasars as the light source, the satellite could detect telltale absorption features from... ... oxygen VI in the halo of our Milky Way: This high ionization measured in 11 out of 12 gas clouds analyzed cannot have been caused by simple UV irradiation. Instead the clouds were most likely shocked in supernova explosions which also ejected them into the halo - another confirmation for the popular 'galactic fountain' scenario (see Update # 160 story 3). ... molecular hydrogen "nearly everywhere" in the Milky Way - except in the Far UV this most abundant interstellar molecule is very hard to study. FUSE is thousands of times more sensitive than previous spacecraft and has now detected H2 in many places in the Galaxy as well as in the LMC and SMC. Differences in the stellar wind of massive stars in different environments were studied by FUSE using spectral line shaps: Massive stars in the LMC have much higher wind speeds as similar stars in the SMC. What's causing the differences is unclear. This spring, FUSE should finally start doing its deuterium work; the satellite is already performing observations on a routine basis for both members of the Principal Investigator Team and for sixty two (62) Guest Investigators from around the world selected by NASA for the first year of operations.	Details and pictures about the three topics. GSFC Release and U. WI-M Press Release plus an ABC Story on the halo oxygen. U. of Colorado Press Release on the molecular hydrogen. NRC Canada on the wind speeds. Update # 136 had many previews of FUSE's primary objectives (in the header).
Near-IR Background discovered in COBE data; sets tight constraints on star formation history A new "cosmic signal" has been discovered with the DIRBE instrument of the Cosmic Background Explorer (COBE), excess radiation at wavelenghts between 2.2 and 3.5 micrometers. This discovery enables astronomers to set tight constraints on the star formation history of the universe. Previously, only theoretical estimates were available of how much matter in the universe had been converted to stars. Stars are born surrounded by dust, which absorbs visible light, so infrared data are required. The announcement - made at a conference on Jan. 12 - marks the end of a decade of cosmological discoveries coming from COBE, which started with another announcement on Jan. 13, 1990 (that the cosmic microwave background spectrum was extremely close to a blackbody with a temperature of 2.7 degrees above absolute zero). Two years ago the DIRBE team reported the discovery of a far-infrared background at much longer wavelengths: 140 and 240 micrometers (see Update # 68 story 3). This is radiation that has been absorbed by cold dust in distant galaxies and reradiated at long wavelengths. The near-infrared radiation announced today is a direct detection of the short wavelength emission from stars or active galactic nuclei that has been redshifted by the expansion of the universe. Now both the short and long wavelength parts of the Cosmic Infrared Background (CIRB) are known. The total amount of radiation in this near-infrared background is about equal to that in the far-infrared background. The sum of these IR backgrounds amounts to 6 % of the radiation in the cosmic blackbody radiation which is left over from the Big Bang. This is an indication of the total amount of power that has been produced in the lifetime of the universe by sources of any kind: stars, accreting black holes (if they exist) or hypothetical exotic subatomic particles (dito). The near-infrared background has now been seen - after careful subtraction of all foreground sources - at a level about three times higher than the minimum provided by faint galaxies already seen as individuals.	UCLA Press Release. COBE's new homepage and DIRBE images. More astrophysics stories: Massive clusters of 3 very different ages in 1 galaxy have been found in NGC 6822 or Barnard's Galaxy - they are 15 and 1.8 billion and 100 million years old, showing that Barnard's Galaxy is significantly different from the Milky Way: Univ. of Washington Press Release and an image of the cluster "Hubble VII". 70 new and very distant RR Lyrae stars have been discovered in the Milky Way - this will allow, for the first time, the study of the structure and properties of the whole halo, not only its innermost parts. There has been increasing evidence that the Milky Way could have been literally eating small nearby satellite galaxies and many of the stars that now belong to the galaxy could have originated in a different place: Yale Press Release. The atmosphere of Betelgeuse pulsates asymmetrically - there are small regions on that star's surface where gas is sometimes being expelled at one side while simultaneously splashing down at the other, HST observations show: CfA Press Release, Space.com story.

SRTM remains set for the 31st NASA on Jan. 13 secured a launch date for shuttle Endeavour, clearing the way for a Jan. 31 flight to map the Earth in unmatched detail: Space.com, SpaceViews, Fla. Today. Who will get access to which level of detail? Space.com. More previews (in German): ZEIT, RP. Mir commercialisation a better approach than NASA's ISS? "Russia has a head start: they have a functional space station. We don't" - deep insights from SpaceRef. What's the investor up to? BBC. How a stellar wind interacts with the interstellar medium has been imaged in great detail by the HST - the "Bubble Nebula" (NGC 7635) is "very complicated": STScI Press Release, ExplZone, Space.com, BBC stories. Meanwhile Hubble has reportedly taken the first post-repair images: BBC. How the Servicing Mission went is summarized by ESA Science News. Rumors about deorbiting plans for aging CGRO "Word has it that NASA is considering a deliberate deorbit (hence destruction) of the Compton Gamma Ray Observatory (GRO). Some investigators have already been informed that GRO may not be around much longer," NASA Watch is reporting on Dec. 13: "One of the spacecraft's three gyroscopes is acting up. Sadly, GRO was designed, as was Solar Max, to be repaired/refurbished on-orbit by a Space Shuttle mission. Apparently no one at NASA feels like fixing it." Another delay for the first X-33 flight is inevitable because fuel tanks have defects and may be abandoned, the experimental carrier's manufacturer said - the first "mission" could slip to 2002: Fla. Today. Hughes sells satellite business to Boeing Hughes Electronics sold its satellite systems business to Boeing in a multi-billion deal - Boeing will pay $3.75 billion in cash: Hughes, Boeing press releases, SpaceViews story.

Refurbished Minuteman to launch several satellites For the first time ever, the Air Force will use a refurbished Minuteman II rocket motor combined with Pegasus XL upper stages to launch satellites into orbit at 2:54 UTC on Jan. 15th from Vandenberg. The payloads are integrated to the "Joint Air Force Academy Weber State University Satellite" or JAWSAT: FalconSat, ASUSAT, OPAL and Optical Calibration Sphere Experiment. Also attached to the multi-payload adapter are two experiments: the Plasma Experiment Satellite and the Attitude Controlled Platform: USAF Press Release. How severe was the NRO Y2K breakdown? It's all pretty classified, and so who's to decide which representation of the events at a reconnaissance satellite data center on Jan. 1st is correct: the Chicago Tribune's version (based on "multiple sources") in which the U.S. was essentially blinded for 3 days, or the Pentagon's story that it was a severe glitch but lasted only hours? In any case the agency was not as Y2K ready as it had believed: Space Daily, Fla. Today. The speculations: SpaceViews. IKONOS images of the North Korean launch site where the Taepo Dongs come from (Update # 101) have been published by the FAS. This material is history-making in itself: hi-res satellite reconnaissance for everyone, as discussed in this NYT Magazine article already referenced in Update # 148 (small items). "Reconciling Observations of Global Temperature Change" A detailled study that says global warming is here (although it doesn't discuss who or what is to blame) is available online in an arcane format; stories on the study by AP, Space Daily. TRMM satellite improves rain forecasts in the tropics by as much as 100%: GSFC Press Release, ExploreZone story. European race for new navigation system - dozens of European companies are racing to complete work on $78 million in contracts that lay the groundwork for a new European satellite system for navigation: Space.com. Cape Canaveral is a fish sanctuary - populations of game fish are more than twice as abundant as in nearby fishable areas around Kennedy Space Center: ExploreZone. Space Tourism prospects - a detailled review of current ideas, initiatives from Fla. Today. Soon first light for VLT UT3 "Melipal", in late January: ESO Press Photos.

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