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By Daniel Fischer Every page present in Europe & the U.S.!
| Ahead | Awards 
The latest issue!
| A German companion - only available here! Current mission news: MGS (latest pictures!) + Cassini + Stardust |
(in the evening, for the N hemisphere): S&T, SC. A full apparition of Mercury: APOD.
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Close, bright Gamma Ray Burst has clearest link to a supernova yetFirst it was hailed as one of the brightest and - with a redshift of just 0.168 - also closest Gamma Ray Bursts ever detected, and now GRB 030329 has become even more important: One week after the burst the spectrum of its optical afterglow has morphed into that of a supernova! "The early spectra consist of a power-law continuum," write Krzysztof Stanek et al., "with narrow emission lines originating from HII regions in the host galaxy, indicating a low redshift of z=0.1687. However, our spectra taken after 2003 Apr. 5 show broad peaks in flux characteristic of a supernova. Correcting for the afterglow emission, we find the spectrum of the supernova is remarkably similar to the type Ic `hypernova' SN 1998bw. While the presence of supernovae have been inferred from the light curves and colors of GRB afterglows in the past, this is the first direct, spectroscopic confirmation that a subset of classical gamma-ray bursts originate from supernovae."The investigation had begun on March 29 when NASA's High-Energy Transient Explorer satellite (HETE-2) discovered one of the brightest and closest gamma-ray bursts on record. Located in the constellation Leo, the 30-second burst outshone the entire Universe in gamma rays, and its optical afterglow was still over a trillion times brighter than the Sun two hours later. At the very moment of the burst, the source should even have shone with 5th magnitude in the sky, briefly visible to the naked eye. Through observations of that afterglow on subsequent nights, astronomers have now spotted the telltale signs of a supernova. Stanek's team cannot yet determine the timing of the burst relative to the supernova (whether one preceded the other or whether both began at the same time), but the same event - a star explosion - was certainly the trigger for both. "All gamma-ray bursts may have associated supernovae that are too faint to observe," says another team member, "but this burst [...] was one of the closest known. We caught it in the act." |
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Are all elliptical galaxies devoid of Dark Matter?"Dark Matter", the mysterious material that seems to make up most of the mass of galaxies, is not as all-pervasive as previously believed: Surprising new results from studies of several elliptical galaxies show they are not surrounded by halos of dark matter as was expected. Only the beautiful spiral galaxies contain gas that allows measurements of their rotation curve (i.e. angular velocity as a function of distance from the center) to be made via the Doppler effect - the other main class of galaxy, the elliptical systems, cannot be studied in this way. It has, however, long been assumed that these galaxies are also enveloped by similar "dark halos" as the spiral galaxies, which cause their outer regions to rotate much faster than they should, based on the stars alone.Now, though, a new study casts serious doubts on this seemingly-reasonable assumption. With a new instrument, the Planetary Nebula Spectrograph at the 4.2-meter WHT on La Palma, the first systematic study of velocities in the outer parts of ordinary elliptical galaxies has been made with the help of planetary nebulae which also have emission lines. Clear results exist now from three galaxies and supporting data from several others: The relatively low speeds of planetary nebulae far from the galactic centers are what one would expect if there were little or no dark matter around these galaxies! Since elliptical galaxies are mostly found in dense galaxy clusters, and this makes for a pretty rough environment with frequent collisions between galaxies. This kind of violent interaction might well also be responsible for stripping away these galaxies' dark halos, but that is just speculation at this point. |
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NASA authorizes construction phase for New Horizons!NASA has finally authorized the New Horizons Pluto-Kuiper Belt mission to go forward with spacecraft and ground system construction - New Horizons is led by the Southwest Research Institute (SwRI) and the Johns Hopkins University Applied Physics Laboratory (APL). The mission is proceeding toward a January 2006 launch, with an arrival at Pluto and its moon, Charon, as early as the summer of 2015. The 415-kilogram spacecraft will characterize the global geology and geomorphology of Pluto and Charon, map the surface compositions and temperatures of these worlds, and study Pluto's unique atmosphere in detail. It will then visit one or more icy, primordial bodies in the Kuiper Belt, beyond the orbits of Neptune and Pluto, where it will make similar investigations. The spacecraft carries seven separate sensor packages to carry out these studies.Baseline plans for the New Horizons mission include use of a radioisotope thermoelectric generator (RTG), which could supply over 200 watts of electrical power for the spacecraft. NASA's authorization to build the New Horizons Pluto-Kuiper Belt mission follows an in-depth review of the entire project by a NASA review team that included more than two dozen experts in all facets of mission development and management. The team worked almost six months before presenting its final report to NASA Headquarters on March 3, 2003. NASA had selected New Horizons on Nov. 29, 2001, after a competition between various industry-university teams who responded to a NASA request for proposals released in January 2001. Since selection, the New Horizons mission and science team has been working to complete both the detailed design of the spacecraft, its instruments and so on. |
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STS-107/ISS UpdateColumbia was already badly damaged when she began her return to Earth, data from the OEX recorder show - and the mystery radar object tracked soon after launch probably came from somewhere on the left wing: Statement by O'Keefe on April 8, an ASAP statement on running the ISS with just 2 crew members, an ISS Status Report on an EVA on April 8, a CAIB Release on the OEX data, a NASA Press Release [illustrated] on the Expedition 7 crew, an updated timeline and coverage of April 12: FT, BBC, Rtr, AFP. |
April 11:
FT,
CNN,
AP.
April 10:
AFP.
April 9:
BBC 2,
1,
WP,
SC 2,
1,
ST 2,
1.
April 8:
SN 2,
1,
New Sci.,
WP,
FT 3,
2,
1,
AP 2,
1,
Rtr, AFP,
UPI,
Rtr.
April 7:
FT
3,
2,
1,
AP,
AFP,
UPI,
SC.
April 5:
AP 2,
1,
WP.
April 4:
FT,
SC,
NZ.
April 3:
FT,
AFP 3,
2,
1,
AP,
ST,
NZ.
April 2:
New Sci.,
BBC,
Dsc,
SR,
FT 2,
1,
SC,
BBC 2,
1,
ST.
April 1:
SN,
Dsc,
WP 2,
1,
UPI,
FT 2,
1,
ST 2,
1,
AP 4,
3,
2,
1,
Guardian,
NZ.
March 31:
SN 2,
1,
Dsc,
WP,
FT,
AFP,
UPI,
AP 2,
1,
BBC,
CNN,
ST.
March 30:
SN,
WP,
FT 2,
1,
UPI,
ST.
March 29:
SN,
FT 2,
1,
ST.
Another $135m for OSP work given out by NASA, leading up to crucial decisions in 2004: NASA Release. |
World's biggest digital imager ready to explore the UniverseIt's the ultimate CCD camera, now at work at CFHT - 36 chips, 340 Megapixels, 25 x 25 cm area, 1° x 1° field: Special page, BBC.One new moon for Saturn - and the Jovian moon count rises to 58The first new moon of Saturn in 3 years has been found: IfA Press Release, Ast., BBC, SC. And another 6 minor moons have been discovered and considered convincing during the great Hawaiian hunt: Press Release in progress, Ast., BBC, NZ. What to call a moon: SC.Did Galileo find several small moons near Amalthea? Galileo detected the objects as bright flashes seen by its star scanner; the data were downlinked only much later: JPL Release, SC. Some asteroids are like onionsA new study of several meteorites collected on Earth and thought to have come from the same large asteroid reveal the structure of the parent space rock to have been something like an onion, with layer upon layer of differing structure: Nature, SC, NZ.Another crater related to dino-killer asteroid? There is a chance that the dino killer asteroid was not alone when it walloped the Earth 65 million years ago: Dsc. More debate in consequences of K/T impact: NSU, NZ. New launch date for Deep Impact, but the impact stays in July 2005: Message, Homepage, Discovery feature. Delta carries GPS satellite but not ProSEDSA Delta 2 booster successfully launched a Global Positioning System (GPS) satellite on March 31: SN, ST, SC. But the ProSEDS space tether experiment originally booked for the same booster was pulled for safety reasons.
The (generic) Ariane 5 has returned to flightlate on April 9, placing two satellites in orbit: Arianespace, ESA Releases, SN, New Sci., BBC, ST, AFP, SC, NZ, Status. Earlier: AFP, BBC, ST, NZ. Still earlier: SN, New Sci., AFP, NZ.Pretty pictures
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Launch of SIRTF delayed another weekto about April 26 because of concerns associated with the Boeing Delta 2 rocket that will send $1.2 billion mission into space, sources say - officials at NASA HQ called for further reviews before clearing the new rocket for flight: SN, UPI, ST, plus previews from AW&ST and the U of A.Cosmic dust in farthest quasar clue to early star formationEnormous quantities of cosmic dust have been found in the most distant quasar with a redshift of 6.43 - thus stars must have already formed and exploded during those first 900 million years since the Big Bang: RAS Release. Galaxies of stars shrouded in dust found in the early Universe: RAS Release.Gravitational lens used for radio imaging of distant galaxy, a young galaxy with a central disk of gas in which hundreds of new stars were being born every year: a paper by Carilli & al., NRAO and MPG [MPIfR] Releases, SC, NZ. Legacy of starburst is a nest of X-ray pulsars in the SMC - three years of observations with RXTE have discovered 36 X-ray binary pulsars, and the count is still rising: RAS Press Release. Stellar census detects more red and brown dwarfsAstronomers have applied a relatively simple test to pick out objects they thought might be faint red dwarfs and their even dimmer cousins, brown dwarfs, belonging to a young star cluster in Orion - the bounty consists of 67 very low mass objects in the cluster, about half of which are brown dwarfs: RAS Release.Dark solar tadpoles explained by TRACE: GSFC Release. Details of the solar furnace becoming even clearer: NSU, SC. Sun's role in climate change continues to spark controversy: RAS Release, BBC. Black holes really are holes(i.e. objects without a surface) says a new paper based on over 6 years of operation of NASA's Rossi X-ray Timing Explorer: RAS Release, New Sci., NZ. Black holes & travel: Wired, UPI, SC. Most powerful quasar in the local Universe blows its top: RAS Release. "Skinny" galaxy harbors massive black hole at core: Berkeley Release.LIGO in action again, beginning another science run: Caltech Release, SC. Linde on precision cosmology: Stanford Release. More cosmic foam questions: NSU.
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Compiled and written by Daniel Fischer
(send me a mail to dfischer@astro.uni-bonn.de!), Skyweek