|
|
A Mystery In Gamma Rays
| Title |
A Mystery In Gamma Rays |
| Explanation |
Gamma rays [ http://cossc.gsfc.nasa.gov/cossc/outreach/nasm/VU/ ] are the most energetic form of light, packing a million or more times the energy of visible light photons. What if you could see [ http://cossc.gsfc.nasa.gov/cossc/outreach/images/ ] gamma rays? If you could, the familiar skyscape [ http://antwrp.gsfc.nasa.gov/apod/ap990410.html ] of steady stars would be replaced [ http://antwrp.gsfc.nasa.gov/apod/ap980321.html ] by some of the most bizarre objects known [ http://www.skypub.com/tips/basics/dsonames.html ] to modern astrophysics [ http://ads.harvard.edu/ ] -- and some which are "unknown". When the EGRET [ http://lheawww.gsfc.nasa.gov/docs/gamcosray/EGRET/ instrument_description.html ] instrument on the orbiting Compton Gamma-ray Observatory [ http://antwrp.gsfc.nasa.gov/apod/ap000116.html ] surveyed the sky in the 1990s, it cataloged 271 celestial sources [ http://cossc.gsfc.nasa.gov/cossc/descriptions/ egret_src.html ] of high-energy gamma-rays. These sources are very different from the powerful gamma-ray bursters [ http://antwrp.gsfc.nasa.gov/apod/ap991104.html ] that flash and fade rapidly from view, and researchers identified some with exotic black holes [ http://antwrp.gsfc.nasa.gov/apod/ap980729.html ], neutron stars [ http://cossc.gsfc.nasa.gov/cossc/outreach/descriptions/ egret_pulsars.html ], and distant flaring galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap981226.html ]. But 170 of the cataloged sources, shown in the above all-sky [ http://antwrp.gsfc.nasa.gov/apod/ap980523.html ] map, remain unidentified. Many sources [ http://pao.gsfc.nasa.gov/gsfc/spacesci/structure/cgro.htm ] in this gamma-ray mystery map likely belong to the already known classes of gamma-ray emitters and are simply obscured or too faint to be otherwise positively identified. However, astronomers recently called attention [ http://pao.gsfc.nasa.gov/gsfc/spacesci/structure/cgro.htm#press ] to the ribbon of sources winding through the plane of the galaxy, projected here along the middle of the map, which may represent a large unknown class of galactic gamma-ray emitters. In any event, the unidentified sources could remain a mystery until the planned launch of the more sensitive Gamma-ray Large Area Space Telescope [ http://www-glast.sonoma.edu/ ] in 2005. |
|
Gamma-Ray Earth
| Title |
Gamma-Ray Earth |
| Explanation |
The pixelated planet above is actually our own planet Earth seen in gamma rays [ http://universe.nasa.gov/press/2005/050325b.html ] - the most energetic form of light. In fact, the gamma rays [ http://cossc.gsfc.nasa.gov/epo/vu/overview/whatare/ process.html ] used to construct this view [ http://heasarc.gsfc.nasa.gov/docs/objects/heapow/archive/ solar_system/cgro_earth.html ] pack over 35 million electron volts [ http://hyperphysics.phy-astr.gsu.edu/hbase/ electric/ev.html#c1 ] (MeV) compared to a mere two electron volts (eV) for a typical visible light photon. The Earth's gamma-ray glow [ http://antwrp.gsfc.nasa.gov/apod/ap060527.html ] is indeed very faint, and this image was constructed by combining data from seven years of exposure during the life of the Compton Gamma Ray Observatory [ http://cossc.gsfc.nasa.gov/ ], operating [ http://cossc.gsfc.nasa.gov/epo/vu/overview/gro/ gro.html ] in Earth orbit from 1991 to 2000. Brightest near the edge and faint near the center, the picture indicates that the gamma rays are coming from high in Earth's atmosphere. The gamma rays are produced as the atmosphere interacts with high energy cosmic rays [ http://antwrp.gsfc.nasa.gov/apod/ap001202.html ] from space, blocking [ http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ multiwavelength_astronomy/multiwavelength_astronomy/ orbit.html ] the harmful radiation from reaching the surface. Astronomers need to understand [ http://xxx.lanl.gov/abs/astro-ph/0410487 ] Earth's gamma-ray glow well as it can interfere with observations of cosmic gamma-ray sources [ http://cossc.gsfc.nasa.gov/epo/vu/index.html ] like pulsars, supernova remnants [ http://antwrp.gsfc.nasa.gov/apod/ap041105.html ], and distant active galaxies powered by supermassive black holes [ http://csep10.phys.utk.edu/astr162/lect/active/ smblack.html ]. |
|
Gamma-Ray Moon
| Title |
Gamma-Ray Moon |
| Explanation |
If you could see gamma rays [ http://antwrp.gsfc.nasa.gov/apod/ap000722.html ] - photons with a million or more times the energy of visible light - the Moon would appear brighter than the Sun! The startling notion is demonstrated by this image of the Moon from the Energetic Gamma Ray Experiment Telescope (EGRET [ http://cossc.gsfc.nasa.gov/docs/cgro/cgro/egret.html ]) in orbit on NASA's Compton Gamma Ray Observatory [ http://cossc.gsfc.nasa.gov/docs/cgro/index.html ] from April 1991 to June 2000. Then, the most sensitive instrument of its kind, even EGRET could not see the quiet Sun which is extremely faint at gamma-ray energies. So why [ http://www.aas.org/publications/baas/v28n4/aas189/abs/ S025002.html ] is the Moon bright? High energy charged particles, known as cosmic rays [ http://imagine.gsfc.nasa.gov/docs/features/topics/snr_group/ cosmic_rays.html ], constantly bombard the unprotected lunar surface generating gamma-ray photons. EGRET's gamma-ray vision [ http://cossc.gsfc.nasa.gov/docs/cgro/epo/vu/ index.html ] was not sharp enough to resolve a lunar disk or any surface features, but its sensitivity reveals the induced gamma-ray [ http://antwrp.gsfc.nasa.gov/apod/ap050331.html ] moonglow. So far unique [ http://glast.gsfc.nasa.gov/ ], the image was generated from eight exposures made during 1991-1994 and covers a roughly 40 degree wide field of view with gamma-ray intensity represented in false color. |
|
GLAST Gamma Ray Sky Simulati
…
| Title |
GLAST Gamma Ray Sky Simulation |
| Explanation |
What shines in the gamma-ray sky? This simulated image models the intensities of gamma rays [ http://cossc.gsfc.nasa.gov/epo/nasm/VU/index.html ] with over 40 million times the energy of visible light, and represents how the sky might appear to the Gamma-ray Large Area Space Telescope [ http://glast.gsfc.nasa.gov ] (GLAST) after its first year in orbit. Familiar steady stars are absent from the dramatic 80x80 degree field which looks directly away from the center of the Galaxy. Instead, the Geminga [ http://imagine.gsfc.nasa.gov/docs/science/how_l2/timing.html ] and Crab pulsars [ http://oposite.stsci.edu/pubinfo/pr/96/22.html ] - bizarre, spinning stellar corpses known to be neutron stars [ http://antwrp.gsfc.nasa.gov/apod/ap980425.html ] - are the two brightest gamma-ray sources. These and other gamma-ray bright objects in the field, monstrous active galaxies [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/ active_galaxies.html ] and still unknown [ http://antwrp.gsfc.nasa.gov/apod/ap000324.html ] sources, have been detected by the Energetic Gamma-Ray Experiment Telescope [ http://cossc.gsfc.nasa.gov/cossc/egret/ ] (EGRET) on the orbiting Compton Gamma-Ray Observatory [ http://cossc.gsfc.nasa.gov ]. However, most of the simulated sources are new - extrapolating current ideas and anticipating discoveries resulting from GLAST's improved gamma-ray vision [ http://glast.gsfc.nasa.gov/ Anticen/ ]. The central broad band of faint gamma-ray emission is due to high-energy cosmic rays [ http://antwrp.gsfc.nasa.gov/apod/ap980618.html ] colliding with interstellar gas in the outer spiral arms of the Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap980523.html ], while below is a diffuse energetic glow from prominent molecular clouds [ http://antwrp.gsfc.nasa.gov/apod/ap970430.html ] in Monoceros, Orion, Auriga, and Taurus. Intended to explore [ http://www-glast.sonoma.edu/ ] extreme environments in the distant cosmos [ http://universe.gsfc.nasa.gov/ ] and planned for launch in 2005, GLAST is under development by NASA, U.S., and international partners. |
|
ROSAT Explores The X-Ray Sky
| Title |
ROSAT Explores The X-Ray Sky |
| Explanation |
Launched in 1990, the orbiting ROSAT observatory [ http://heasarc.gsfc.nasa.gov/docs/rosat/rosat.html ] explored the Universe by viewing the entire sky in x-rays [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/ history1_xray.html ] -- photons with about 1,000 times more energy than visible light. This ROSAT survey [ http://www.xray.mpe.mpg.de/rosat/survey/sxrb/12/ass.html ] produced the sharpest, most sensitive image of the x-ray sky to date. The all-sky image is shown with the plane of our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap980523.html ] running horizontally through the center. Both x-ray brightness and relative energy are represented with red, green, and blue colors indicating three x-ray energy ranges (from lowest to highest). Bright x-ray spots near the galactic plane are within our own Milky Way. The brightest region (right of center) is toward the Vela Pulsar [ http://antwrp.gsfc.nasa.gov/apod/ap000609.html ] and the Puppis supernova remnant [ http://antwrp.gsfc.nasa.gov/apod/ap991209.html ]. Bright sources beyond our Galaxy are also apparent, notably the Virgo cluster of galaxies [ http://www.seds.org/messier/more/virgo.html ] (near top right) and the Large Magellanic Cloud (LMC) [ http://www.seds.org/messier/xtra/ngc/lmc.html ]. The LMC is easy to find here as several of the black stripes (blank areas caused by missing data) seem to converge on its position (lower right). Over large areas of the sky a general diffuse background of x-rays [ http://chandra.harvard.edu/press/00_releases/ press_011400bg.html ] dominates. Hot gas in our own Galaxy provides much of this background and gives rise to the grand looping structures [ http://antwrp.gsfc.nasa.gov/apod/ap990503.html ] visible in the direction of the galactic center (image center). Unresolved extragalactic sources also add to this background, particularly above and below the plane. Despite the x-ray sky's exotic appearance, a very familiar feature is visible - the gas and dust clouds which line the plane of our galaxy absorb x-rays as well as optical light and produce the dark bands running through the galactic center [ http://antwrp.gsfc.nasa.gov/apod/ap000629.html ]. |
|
A Mystery In Gamma Rays
| Title |
A Mystery In Gamma Rays |
| Explanation |
Gamma rays [ http://cossc.gsfc.nasa.gov/epo/nasm/VU/index.html ] are the most energetic form of light, packing a million or more times the energy of visible light photons. If you could see gamma rays, the familiar skyscape [ http://antwrp.gsfc.nasa.gov/apod/ap990410.html ] of steady stars would be replaced [ http://antwrp.gsfc.nasa.gov/apod/ap980321.html ] by some of the most bizarre objects known [ http://www.skypub.com/tips/basics/dsonames.html ] to modern astrophysics [ http://ads.harvard.edu/ ] -- and some which are "unknown". When the EGRET [ http://lheawww.gsfc.nasa.gov/docs/gamcosray/EGRET/ instrument_description.html ] instrument on the orbiting Compton Gamma-ray Observatory [ http://antwrp.gsfc.nasa.gov/apod/ap000116.html ] surveyed the sky in the 1990s, it cataloged 271 celestial sources [ http://cossc.gsfc.nasa.gov/gamcat/catform.html ] of high-energy gamma-rays. Researchers identified some with exotic black holes [ http://antwrp.gsfc.nasa.gov/apod/ap980729.html ], neutron stars [ http://antwrp.gsfc.nasa.gov/apod/ap010719.html ], and distant flaring galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap981226.html ]. But 170 of the cataloged sources, shown in the above all-sky [ http://antwrp.gsfc.nasa.gov/apod/ap980523.html ] map, remain unidentified. Many sources [ http://pao.gsfc.nasa.gov/gsfc/spacesci/structure/cgro.htm ] in this gamma-ray mystery map likely belong to already known classes of gamma-ray emitters and are simply obscured or too faint to be otherwise positively identified. However, astronomers have called attention [ http://pao.gsfc.nasa.gov/gsfc/spacesci/structure/cgro.htm#press ] to the ribbon of sources winding through the plane of the galaxy, projected here along the middle of the map, which may represent a large unknown class [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query? bibcode=2000HEAD...32.4007G&db_key=AST&high=3af6c03e8125794 ] of galactic gamma-ray emitters. In any event, the unidentified sources could remain a mystery until the planned launch of the more sensitive Gamma-ray Large Area Space Telescope [ http://www-glast.sonoma.edu/ ] in 2005. |
|
The Gamma Ray Sky
| Title |
The Gamma Ray Sky |
| Explanation |
What if you could see gamma rays [ http://cossc.gsfc.nasa.gov/epo/vu/ ]? If you could, the sky would seem to be filled with a shimmering high-energy glow from the most exotic and mysterious objects [ http://www.pbs.org/wgbh/nova/gamma/ ] in the Universe. In the early 1990s NASA's orbiting Compton Observatory [ http://antwrp.gsfc.nasa.gov/apod/ap000408.html ], produced this premier vista of the entire sky in gamma rays [ http://www.gamma.mpe-garching.mpg.de/~rod/public/ tvuniv.htm ], photons with more than 40 million times the energy of visible light [ http://www.pbs.org/wgbh/nova/gamma/spectrum.html ]. The diffuse gamma-ray glow from the plane of our Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap970517.html ] Galaxy runs horizontally through the false-color image. The brightest spots in the galactic plane (right of center) are pulsars [ http://antwrp.gsfc.nasa.gov/apod/ap000609.html ], spinning magnetized neutron stars formed in the violent crucibles of stellar explosions [ http://antwrp.gsfc.nasa.gov/apod/ap980425.html ]. Above and below the plane, quasars [ http://antwrp.gsfc.nasa.gov/apod/ap971206.html ], believed to be powered by supermassive black holes, produce gamma-ray beacons at the edges of the universe. The nature of many [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query? 1996A%26AS%2E%2E120C%2E465M&db_key=AST ] of the fainter sources remains unknown [ http://antwrp.gsfc.nasa.gov/apod/ap010811.html ]. |
|
The Milky Way's Gamma-Ray Ha
…
| Title |
The Milky Way's Gamma-Ray Halo |
| Explanation |
Our Milky Way galaxy appears to be surrounded by a halo of gamma rays [ http://tigre.ucr.edu/halo/halo.html ]. Gamma rays are the most energetic form of electromagnetic radiation [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html ], with more than a hundred thousand times the energy of visible light, but known gamma-ray sources [ http://antwrp.gsfc.nasa.gov/apod/ap970222.html ] don't account for the diffuse distribution of this high-energy glow. This surprising result is based on data [ http://tigre.ucr.edu/halo/tipsh.html ] from the EGRET instrument onboard the Compton Gamma Ray Observatory [ http://antwrp.gsfc.nasa.gov/apod/ap970606.html ]. In this false color all-sky image centered on the Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap970517.html ], the brown and green regions indicate brighter, known sources of gamma-rays. The galactic center and plane clearly standout as do some distant galaxies seen near the top and bottom of the picture. The dim, blue regions above and below the plane correspond to our Galaxy's unexpected gamma-ray halo. " What causes the halo? " Future gamma-ray telescopes [ http://www-glast.stanford.edu ] could solve this mystery. However, the excitement has already inspired tantalizing speculation about the solution including, collisions of low energy photons with high-energy cosmic rays [ http://antwrp.gsfc.nasa.gov/apod/ap961016.html ], high energy electrons accelerated by a previous burst of Milky Way star formation [ http://antwrp.gsfc.nasa.gov/apod/ap971027.html ], and exotic interacting particles which make up Dark Matter [ http://antwrp.gsfc.nasa.gov/htmltest/gifcity/matter.html ]. |
|
A Mystery In Gamma Rays
| Title |
A Mystery In Gamma Rays |
| Explanation |
Gamma rays [ http://cossc.gsfc.nasa.gov/epo/vu/ ] are the most energetic form of light, packing a million or more times the energy of visible light photons. If you could see gamma rays, the familiar skyscape [ http://antwrp.gsfc.nasa.gov/apod/ap040304.html ] of steady stars would be replaced [ http://antwrp.gsfc.nasa.gov/apod/ap980321.html ] by some of the most bizarre objects known [ http://skyandtelescope.com/howto/basics/ article_240_1.asp ] to modern astrophysics [ http://ads.harvard.edu/ ] -- and some which are "unknown". When the EGRET [ http://lheawww.gsfc.nasa.gov/docs/gamcosray/EGRET/ instrument_description.html ] instrument on the orbiting Compton Gamma-ray Observatory [ http://antwrp.gsfc.nasa.gov/apod/ap000408.html ] surveyed the sky in the 1990s, it cataloged 271 celestial sources [ http://cossc.gsfc.nasa.gov/gamcat/catform.html ] of high-energy gamma-rays. Researchers identified some with exotic black holes [ http://antwrp.gsfc.nasa.gov/apod/ap980729.html ], neutron stars [ http://antwrp.gsfc.nasa.gov/apod/ap010719.html ], and distant flaring galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap981226.html ]. But 170 of the cataloged sources, shown in the above all-sky map, remain unidentified. Many sources [ http://pao.gsfc.nasa.gov/gsfc/spacesci/structure/cgro.htm ] in this gamma-ray mystery map likely belong to already known classes of gamma-ray emitters and are simply obscured or too faint to be otherwise positively identified. However, astronomers have called attention [ http://pao.gsfc.nasa.gov/gsfc/spacesci/structure/cgro.htm#press ] to the ribbon of sources winding through the plane of the galaxy, projected here along the middle of the map, which may represent a large unknown class [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query? bibcode=2000HEAD...32.4007G&db_key=AST&high=3af6c03e8125794 ] of galactic gamma-ray emitters. In any event, the unidentified sources could remain a mystery until the planned launch of the more sensitive Gamma-ray Large Area Space Telescope [ http://www-glast.sonoma.edu/ ] in 2007. |
|
The Gamma Ray Sky
| Title |
The Gamma Ray Sky |
| Explanation |
What if you could "see" gamma rays? [ http://cossc.gsfc.nasa.gov/cossc/nasm/VU/vu.html ] If you could, the sky would seem to be filled [ http://cossc.gsfc.nasa.gov/cossc/pics.html ] with a shimmering high-energy glow from the most exotic [ http://cossc.gsfc.nasa.gov/cossc/news.html ] and mysterious objects in the Universe [ http://antwrp.gsfc.nasa.gov/apod/ap971218.html ]. In the early 1990s NASA's orbiting Compton Observatory [ http://antwrp.gsfc.nasa.gov/apod/ap970606.html ], produced this premier vista of the entire sky in gamma rays [ http://cossc.gsfc.nasa.gov/cossc/nasm/VU/overview/ g_rayuni/g_rayuni.html ] - photons with more than 40 million times the energy of visible light [ http://cossc.gsfc.nasa.gov/cossc/whatgam.html ]. The diffuse gamma-ray glow from the plane of our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap970517.html ] runs horizontally through the false color image. The brightest spots in the galactic plane (right of center) are pulsars [ http://antwrp.gsfc.nasa.gov/apod/ap980211.html ] - spinning magnetized neutron stars formed in the violent crucibles of stellar explosions [ http://antwrp.gsfc.nasa.gov/apod/ap961114.html ]. Above and below the plane, quasars [ http://antwrp.gsfc.nasa.gov/apod/ap971206.html ], believed to be powered by supermassive black holes [ http://antwrp.gsfc.nasa.gov/apod/ap971019.html ], produce gamma-ray beacons at the edges of the universe. The nature of many [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996A%26AS%2E%2E120C%2E465M&db_key=AST ] of the fainter sources remains unknown [ http://www-glast.stanford.edu/ ]. |
|
GLAST Gamma-Ray Sky Simulati
…
| Title |
GLAST Gamma-Ray Sky Simulation |
| Explanation |
This simulated image models the intensities of gamma rays [ http://cossc.gsfc.nasa.gov/cossc/outreach/nasm/VU/ ] with over 40 million times the energy of visible light, and represents how the sky might appear to the proposed Gamma-ray Large Area Space Telescope [ http://glast.gsfc.nasa.gov ] (GLAST) after its first year in orbit. Familiar steady stars are absent from the dramatic 80x80 degree field which looks directly away from the center of the Galaxy. Instead, the Geminga [ http://imagine.gsfc.nasa.gov/docs/science/how_l2/timing.html ] and Crab pulsars [ http://oposite.stsci.edu/pubinfo/pr/96/22.html ] - bizarre, spinning stellar corpses known to be neutron stars [ http://antwrp.gsfc.nasa.gov/apod/ap980425.html ] - are the two brightest gamma-ray sources. These and other bright objects in the field, dense pulsars [ http://antwrp.gsfc.nasa.gov/apod/ap980211.html ], monstrous active galaxies [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/active_galaxies.html ], and still unknown sources, have been detected by the Energetic Gamma-Ray Experiment Telescope [ http://cossc.gsfc.nasa.gov/cossc/egret/ ] (EGRET) on the orbiting Compton Gamma-Ray Observatory [ http://cossc.gsfc.nasa.gov ]. However, most of the simulated point sources are new - extrapolating current ideas and anticipating discoveries resulting from GLAST's improved gamma-ray vision [ http://glast.gsfc.nasa.gov/Anticen/ ]. The central broad band of faint gamma-ray emission is due to high-energy cosmic rays [ http://antwrp.gsfc.nasa.gov/apod/ap980618.html ] colliding with interstellar gas in the outer spiral arms of the Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap980523.html ], while below is a diffuse energetic glow from prominent molecular clouds [ http://antwrp.gsfc.nasa.gov/apod/ap970430.html ] in Monoceros, Orion, Auriga, and Taurus. Intended to explore [ http://perry.sonoma.edu/ ] the most extreme energy sources in the distant cosmos [ http://universe.gsfc.nasa.gov/ ] and planned for launch in 2005, the GLAST mission [ http://wwwmipd.gsfc.nasa.gov/glast/glast.htm ] is under development [ http://glast.gsfc.nasa.gov/Summary/ ] by NASA and a collaboration of U. S. and international partners. |
|
Gamma-Ray Earth
| Title |
Gamma-Ray Earth |
| Explanation |
The pixelated planet above is actually our own planet Earth seen in gamma rays [ http://universe.nasa.gov/press/2005/050325b.html ] - the most energetic form of light. In fact, the gamma rays [ http://cossc.gsfc.nasa.gov/epo/vu/overview/whatare/ process.html ] used to construct this view [ http://heasarc.gsfc.nasa.gov/docs/objects/heapow/archive/solar_system/cgro_earth.html ] pack over 35 million electron volts [ http://hyperphysics.phy-astr.gsu.edu/hbase/ electric/ev.html#c1 ] (MeV) compared to a mere two electron volts (eV) for a typical visible light photon. The Earth's gamma-ray glow [ http://antwrp.gsfc.nasa.gov/apod/ap990417.html ] is indeed very faint, and this image was constructed by combining data from seven years of exposure during the life of the Compton Gamma Ray Observatory [ http://cossc.gsfc.nasa.gov/ ], operating [ http://cossc.gsfc.nasa.gov/epo/vu/overview/gro/ gro.html ] in Earth orbit from 1991 to 2000. Brightest near the edge and faint near the center, the picture indicates that the gamma rays are coming from high in Earth's atmosphere. The gamma rays are produced as the atmosphere interacts with high energy cosmic rays [ http://antwrp.gsfc.nasa.gov/apod/ap001202.html ] from space, blocking [ http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ multiwavelength_astronomy/multiwavelength_astronomy/ orbit.html ] the harmful radiation from reaching the surface. Astronomers need to understand [ http://xxx.lanl.gov/abs/astro-ph/0410487 ] Earth's gamma-ray glow well as it can interfere with observations of cosmic gamma-ray sources [ http://cossc.gsfc.nasa.gov/epo/vu/index.html ] like pulsars, supernova remnants [ http://antwrp.gsfc.nasa.gov/apod/ap041105.html ], and distant active galaxies powered by supermassive black holes [ http://csep10.phys.utk.edu/astr162/lect/active/ smblack.html ]. |
|
STS-37 Gamma Ray Observatory
…
| Title |
STS-37 Gamma Ray Observatory (GRO) grappled by RMS |
| Description |
Backdropped against the Earth's expansive desert in the Mid East, the Gamma Ray Observatory (GRO) with its solar array (SA) panels deployed is grappled by the remote manipulator system (RMS) during STS-37 systems checkout. GRO's four complement instruments are visible: the Energetic Gamma Ray Experiment Telescope (EGRET) (at the bottom), the Imaging Compton Telescope (COMPTEL) (center), the Oriented Scintillation Spectrometer Experiment (OSSE) (top), and Burst and Transient Source Experiment (BATSE) (on four corners). The view was taken by STS-37 crew through an aft flight deck overhead window. |
| Date Taken |
1991-04-11 |
|
STS-37 Gamma Ray Observatory
…
| Title |
STS-37 Gamma Ray Observatory (GRO) grappled by RMS |
| Description |
Backdropped against the Earth's surface, the Gamma Ray Observatory (GRO) with its solar array (SA) panels deployed is grappled by the remote manipulator system (RMS) during STS-37 systems checkout. GRO's four complement instruments are visible: the Energetic Gamma Ray Experiment Telescope (EGRET) (at the bottom), the Imaging Compton Telescope (COMPTEL) (center), the Oriented Scintillation Spectrometer Experiment (OSSE) (top), and Burst and Transient Source Experiment (BATSE) (on four corners). The view was taken by STS-37 crew through an aft flight deck overhead window. |
| Date Taken |
1991-04-11 |
|
|
