http://www.rssboard.org/rss-specification 720 http://ecuip-xtf.lib.uchicago.edu/xtf/search?docsPerPage%3D100;f20-type%3DObservation Results for your query: docsPerPage=100;f20-type=Observation Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/1975ApJ___197___85M/1975ApJ___197___85M.dc.xml The spectrum was recorded with the Copernicus satellite (1972) by Don Morton. The abscissa (x-axis) is in units of Ångstroms and the ordinate (y-axis) is in units of counts per 14 seconds. The spectrum was recorded point by point using a photo cell. The spectrum from 1197 Å to 1254 Å, which took 20 hours to record, contains four types of features: a) the strong absorption from the interstellar hydrogen line known as Lyman alpha near 1216 Å; b) a set of very narrow, deep lines due to neutral nitrogen at 1200 Å, twice ionized silicon at 1206 Å, and once ionized sulfur just past 1250 Å, all from interstellar gas; c) a wind containing four times ionized nitrogen blowing off the surface of the star at 1000 km/second (1233 Å and 1238 Å); d) general undulations across the top which are due to absorption lines in the atmosphere of the star itself. The sharp, narrow interstellar lines, item b, actually contain two components which cannot be distinguished in this spectrum because of insufficient resolution. This is the... http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/1975ApJ___197___85M/1975ApJ___197___85M.dc.xml Sat, 01 Jan 1972 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/HorseheadNebulaSpaceTelescope/HorseheadNebulaSpaceTelescope.dc.xml The Horsehead Nebula is one of the most identifiable nebulae because of the shape of its swirling cloud of dark dust and gases, which resembles to a horse's head when viewed from Earth. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/HorseheadNebulaSpaceTelescope/HorseheadNebulaSpaceTelescope.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/M31-center-HST/M31-center-HST.dc.xml This Hubble Space Telescope image centers on the 100-million-solar-mass black hole at the hub of our neighboring spiral galaxy M31, the Andromeda Galaxy. It is one of the few galaxies outside of the Milky Way that is visible to the naked eye. This is the sharpest visible-light image ever made of the nucleus of an external galaxy. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/M31-center-HST/M31-center-HST.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/Swift-ScoX-1/Swift-ScoX-1.dc.xml This image from the Swift X-ray Telescope shows an X-ray nova (designated J1745-26) and Scorpius X-1, along with the scale of moon, as they would appear in the field of view from Earth. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/Swift-ScoX-1/Swift-ScoX-1.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/Tumlinson_fig4/Tumlinson_fig4.dc.xml The LMC star is Sanduleak -67 166. The top two panels cover the spectral region from 920 - 1120 Å. To obtain this spectrum a special telescope, FUSE, had to be built with very few reflections and with a much more sophisticated detector than was used for Copernicus. This spectrum took 60 hours to record, three times longer than it took the Copernicus satellite to observe 50 Å in zeta Ophiuchi, a star that is 10,000 time brighter than this one. For this example, FUSE is effectively 7,500 times more efficient than Copernicus. The spectrum is completely dominated by the lines of molecular hydrogen from interstellar space, some in our Galaxy and some in the Large Magellanic Cloud. The spectrum of molecular hydrogen, which contains two hydrogen nuclei (protons) and two electrons, is obviously much more complex than the spectrum of atomic hydrogen. The vibration of the two protons leads to the bands denoted 1-0, 2-0, 4-0, etc., at the top of the two panels. Within each band are very narrow components more closely sp... http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/Tumlinson_fig4/Tumlinson_fig4.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/Xray-crab/Xray-crab.dc.xml The Crab Nebula, some 6,000 light years from Earth, is the remnant of a supernova explosion. It was seen on Earth in the year 1054. At the center of the bright nebula is a rapidly spinning neutron star, or pulsar, that emits pulses of radiation 30 times a second. This view shows the Crab in the X-ray wavelength. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/Xray-crab/Xray-crab.dc.xml Sun, 29 Aug 1999 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/apj430279f6_hr/apj430279f6_hr.dc.xml The spectra were shifted to appear as if they were not redshifted before being averaged. All the objects have spectra that look like quasi-stellar objects, but some are of low enough luminosity that the host galaxy is visible and has a name. The main features of the spectrum are as follows: a purple/blue line drawn through the spectrum is the "continuum," mostly due to the AGN, a continuous glow caused by a very hot gas in a strong magnetic field; a red line represents the fitted spectrum of emission lines, thought to arise in a disk that surrounds the central black hole of the AGN. (These are most clear at the right end.) The ions that are seen in emission are labelled: N V, C IV, He II etc. The Roman numeral is the charge of the ion plus one: N V is four-times ionized oxygen, meaning that four electrons have been stripped off the atom. The ion has a net charge of positive four. The black line traces the actual data. Below about 950 Å, neutral hydrogen absorption lines from the intergalactic medium exist in ... http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/apj430279f6_hr/apj430279f6_hr.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/chandra-deep-field/chandra-deep-field.dc.xml The Chandra Deep Field South refers to a location in space that offers a relatively clear view through the clouds of gas in our Galaxy, allowing us to clearly see the rest of the Universe in X-rays. This image was created by putting together multiple exposures from Chandra’s Advanced CCD Imaging Spectrometer for a cumulative exposure time of over one-million seconds. The multiwavelength observations of this region were carried out by a team led by Riccardo Giacconi in collaboration with scientists from the Very Large Telescope and the Paranal Observatory, both in Chile. Through the course of these investigations, the X-ray background was determined to originate from the central supermassive black holes of distant galaxies. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/chandra-deep-field/chandra-deep-field.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/cygx1_optical/cygx1_optical.dc.xml Since its discovery in 1962, the X-ray binary star Cygnus X-1 has been one of the most intensively studied cosmic X-ray sources. About a decade after its discovery, Cygnus X-1 secured a place in the history of astronomy when a combination of space-based, X-ray observations by the Chandra X-ray Observatory and optical, ground-based observations by the Digitized Sky Survey led to the conclusion that it was a black hole, the first such identification. This is an optical image of Cygnus X-1. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/cygx1_optical/cygx1_optical.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/cygx1_xray/cygx1_xray.dc.xml Since its discovery in 1962, the X-ray binary star Cygnus X-1 has been one of the most intensively studied cosmic X-ray sources. About a decade after its discovery, Cygnus X-1 secured a place in the history of astronomy when a combination of space-based, X-ray observations by the Chandra X-ray Observatory and optical, ground-based observations by the Digitized Sky Survey led to the conclusion that it was a black hole, the first such identification. This is a Chandra X-ray image of Cygnus X-1. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/cygx1_xray/cygx1_xray.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/fg7/fg7.dc.xml SN1987A is the brightest supernova seen from Earth in several centuries. The abscissa is in kilometers per second (km/sec), and the ordinate goes from 0 to 1 for each panel and reflects the relative strength of each component set. The absorption features shown are predominantly interstellar lines from gas between us and the supernova. However, the supernova is in a nearby galaxy, the Large Magellanic Cloud (LMC). The LMC is just beyond the Milky Way and is moving away from us. The labels above the second spectral strip show groups of interstellar components moving at different velocities, which cannot be resolved separately. The component groups 2, 3, and 4 are in the Milky Way galaxy, and the component groups 5 through 10 are in the LMC. The black dots are the data points, and the black line is a prediction (a model) including all of the subcomponents for what the interstellar spectrum should look like. The model and the data points agree very well. The ions represented are once-ionized nickel, once-ionized ... http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/fg7/fg7.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/grayEarth_petry/grayEarth_petry.dc.xml The pixelated planet above is actually our own planet Earth seen in gamma rays--the most energetic form of light. In fact, the gamma rays used to construct this view pack over 35 million electron volts (MeV) compared to a mere two electron volts (eV) for a typical visible light photon. The Earth's gamma-ray glow 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, operating 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 from space, blocking the harmful radiation from reaching the surface. Astronomers need to understand Earth's gamma-ray glow well as it can interfere with observations of cosmic gamma-ray sources like pulsars, supernova remnants, and distant active galaxies powered by supermassive black hol... http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/grayEarth_petry/grayEarth_petry.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/grb_970228/grb_970228.dc.xml Eight hours after the detection of GRB 970228, BeppoSax was able to isolate an X-ray source at the location in the Orion constellation. This is the first X-ray counterpart data captured following a gamma-ray burst. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/grb_970228/grb_970228.dc.xml Fri, 28 Feb 1997 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/infrared-crab/infrared-crab.dc.xml The Crab Nebula, some 6,000 light years from Earth, is the remnant of a supernova explosion. It was seen on Earth in the year 1054. At the center of the bright nebula is a rapidly spinning neutron star, or pulsar, that emits pulses of radiation 30 times a second. This view shows the Crab in the infrared wavelength. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/infrared-crab/infrared-crab.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/m31einstein/m31einstein.dc.xml This picture taken by the Einstein Observatory points to the galactic center of M31 - the Andromeda Galaxy - the nearest spiral galaxy to our Milky Way galaxy. Using more than 150 observations carried out over 13 years by the Chandra X-ray Observatory, researchers in 2013 identified 26 black hole candidates, the largest number to date, in the Andromeda Galaxy. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/m31einstein/m31einstein.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/misc_gx5-1_moon/misc_gx5-1_moon.dc.xml This image of the Moon in X-rays was made in 1991 using data from the Roentgen Satellite (ROSAT), an X-ray observatory. In this picture, pixel brightness corresponds to X-ray intensity. The Moon reflects lower energy X-rays (shown as red) from the Sun. The source of high energy X-rays (shown as yellow) is a distant binary star system. The background is speckled with X-rays from many distant, powerful active galaxies. The picture also shows the Moon passing in front of of and obscuring the binary star, a phenomenon called occultation. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/misc_gx5-1_moon/misc_gx5-1_moon.dc.xml Tue, 01 Jan 1991 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/optical-crab/optical-crab.dc.xml The Crab Nebula, some 6,000 light years from Earth, is the remnant of a supernova explosion. It was seen on Earth in the year 1054. At the center of the bright nebula is a rapidly spinning neutron star, or pulsar, that emits pulses of radiation 30 times a second. This view shows the Crab in the optical wavelength. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/optical-crab/optical-crab.dc.xml Thu, 01 Jan 1970 12:00:00 GMT http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/radio-crab/radio-crab.dc.xml The Crab Nebula, some 6,000 light years from Earth, is the remnant of a supernova explosion. It was seen on Earth in the year 1054. At the center of the bright nebula is a rapidly spinning neutron star, or pulsar, that emits pulses of radiation 30 times a second. This view shows the Crab in the radio wavelength. http://ecuip-xtf.lib.uchicago.edu/xtf/view?docId=grxr/radio-crab/radio-crab.dc.xml Thu, 01 Jan 1970 12:00:00 GMT