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71. HEAO 1 A2 LED Catalog
ID:
ivo://nasa.heasarc/a2led
Title:
HEAO 1 A2 LED Catalog
Short Name:
A2LED
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The HEAO 1 A-2 LED Catalog of High-Energy X-ray Sources is the result of a study of the diffuse X-ray sky over the bands of X-ray energies 0.18-0.44 keV and 0.44-2.8 keV from August 1977 until January 1979 using data obtained with the A-2 Low Energy Detector on the HEAO 1 satellite. The HEAO A-2 Experiment was primarily designed for studying the diffuse X-ray background; however, it was also capable of studying point sources to good sensitivity. The detectors surveyed over 95 percent of the sky in the spectral bands listed above to typical limiting sensitivities of 1x10**-11 and 3x10**-11 respectively. Using a significance criterion of 6 sigma for existence, 114 sources are cataloged. The catalog contains a list of all counterpart identifications and a cross-reference to all HEAO 1 A-2 LED team publications on the catalog sources complete through the end of 1981. The identified sources fall into several categories, primarily dependent on observing energy interval. In the 1 KeV band the sources include: 20 galactic stellar sources, 19 extragalactic sources, 13 SNR's, 11 galactic bulge sources, 2 globular cluster sources, and 2 previously reported sources without optical counterparts. In the .25 KeV band the sources include: 24 galactic stellar objects, 12 extragalactic sources, 5 SNR's, 1 bulge source, and 1 globular cluster source. This is a service provided by NASA HEASARC .
72. HEAO 1 A1 Lightcurves
ID:
ivo://nasa.heasarc/a1point
Title:
HEAO 1 A1 Lightcurves
Short Name:
A1POINT
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
HEAO 1 (High Energy Astronomical Observatory) is a spinning survey mission X-ray satellite. It launched 12 August 1977 and was in operation until 9 January 1979. HEAO-1 rotated once per 30 minutes about the Earth-Sun line. In this manner, the instruments scanned a great circle in the sky that lay 90 degrees from the sun. A given source near the ecliptic was viewed for a few days while sources near the ecliptic pole were scanned nearly continuously during the entire mission. The satellite has limited pointing capability that was used to produce this data, giving continuous coverage of selected sources. The pointings began about 100 days into the mission. The A1 instrument, also known as the NRL Large Area Sky Survey Experiment (LASS) covered the energy range 0.25 to 25.0 keV. The experiment consisted of seven detectors, six mounted on the -Y side of the spacecraft, the seventh on the +Y side. Two detectors, with a FWHM of 1 deg x 0.5 deg and open area of 1350 cm2 were tilted a third of a degree either towards or away from the Z (Sun-pointed) four other -Y side detectors has a FWHM of 1 deg x 4 deg and an open area of 1650 cm2. The single +Y detector has a FWHM of 2 deg x 8 deg and an open area of 1900 cm2. The experiment had sufficient sensitivity to detect sources as faint as as 0.25 uJy at 5 keV for sources with a Crab-like spectrum. Data was collected in either a 5 or a 320 millisecond timing resolution mode: Full sky coverage for both time resolutions was achieved before the mission's end. Wood et al. (1984) discuss the experiment and a catalog of sources in further detail. This is a service provided by NASA HEASARC .
73. HEAO 1 A3 MC LASS Catalog
ID:
ivo://nasa.heasarc/a3
Title:
HEAO 1 A3 MC LASS Catalog
Short Name:
A3
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
This database table contains information from the HEAO 1 A3 MC LASS Catalog of X-ray Sources. The MC experiment contained two four-grid modulation collimators with an egg-crate collimator with an overall FOV of 4 x 4 degrees (FWHM). The objects in the catalog are possible HEAO 1 A1 sources. The HEAO 1 experiment began on day 224, 19 August 1977 and ended on day 739, 9 January 1979. This is a service provided by NASA HEASARC .
74. HEAO 1 A2 Pointed Lightcurves
ID:
ivo://nasa.heasarc/a2lcpoint
Title:
HEAO 1 A2 Pointed Lightcurves
Short Name:
A2LCPOINT
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The A2 experiment was flown on the HEAO-1 satellite, from August, 1977 until January 1979. The experiment consisted of six multi-layer, multi-anode collimated gas proportional counters. These were two LEDs (Low Energy Detectors), a MED (Medium Energy Detector), and three HEDs (High Energy Detectors). The first 6-months of mission were dedicated to an all-sky scan after which a pointing phase started. This database table accesses the lightcurves available at HEASARC obtained from the A2 MED (small and large field of view) and HEDs (3 units, each with small and large field of view) detectors during the pointed phase. This is a service provided by NASA HEASARC .
75. HEAO 1 A2 Pointing Catalog
ID:
ivo://nasa.heasarc/a2point
Title:
HEAO 1 A2 Pointing Catalog
Short Name:
A2POINT
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The HEAO 1 A-2 Pointing Catalog of High-Energy X-ray Sources is the result of a study of selected targets using the three detectors of the A-2 Experiment. The detectors consisted of the HED (high energy detector) in the range 3-6 KeV, the MED (medium energy detector) in the range 1.5-15 KeV, and the LED (low energy detector) in the range 0.15-3 KeV. The HEAO A-2 Experiment was primarily designed for studying the diffuse X-ray background; however, it was also capable of studying point sources to good sensitivity. Thus, after several months of continuous scanning to survey 95% of the diffuse X-ray sky, the A-2 detectors began individual pointings at selected targets. The point maneuvers began on day 319, 15 November 1977 and ended on day 739, 9 January 1979. This is a service provided by NASA HEASARC .
76. HEAO 1 A2 Scanned Lightcurves
ID:
ivo://nasa.heasarc/a2lcscan
Title:
HEAO 1 A2 Scanned Lightcurves
Short Name:
A2LCSCAN
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The A2 experiment was flown on the HEAO-1 satellite, from August, 1977 until January 1979. The experiment consisted of six multi-layer, multi-anode collimated gas proportional counters. These were two LEDs (Low Energy Detectors), a MED (Medium Energy Detector), and three HEDs (High Energy Detectors). The first 6-months of mission were dedicated to an all-sky scan after which a pointing phase started. This database table accesses the lightcurves available at HEASARC obtained from the A2 MED (small and large field of view) and HEDs (3 units, each with small and large field of view) detectors during the scanning phase. This is a service provided by NASA HEASARC .
77. HEAO 1 A2 Spectra
ID:
ivo://nasa.heasarc/a2spectra
Title:
HEAO 1 A2 Spectra
Short Name:
A2SPECTRA
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The A2 experiment was flown on the HEAO-1 satellite, between August, 1977 until January 1979. The experiment consisted of six multi-layer multi-anode collimated gas proportional counters. These were two LEDs (Low Energy Detectors), a MED (Medium Energy Detector), and three HEDs (High Energy Detectors). The first 6-months of mission were dedicated to an all-sky scan after which a pointing phase started. This database accesses the spectra (and associated files) obtained from the A2 MED (small and large field of view) and HEDs (1 and 3 small and large filed of view) detectors during the pointed phase. The spectra were generated for all HEAO-1 A2 pointed observations except for those in more unusual HEAO-1 modes (RAM-11 and "radical RAMs"). Thus the set of spectra created are only a subset (though a fairly complete one) of the entire catalog of HEAO-1 A2 pointed observations. This is a service provided by NASA HEASARC .
78. HEAO 1 A4 Spectra
ID:
ivo://nasa.heasarc/a4spectra
Title:
HEAO 1 A4 Spectra
Short Name:
A4SPECTRA
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The UCSD/MIT Hard X-Ray and Low-Energy Gamma-Ray Instrument, A4, was flown on the HEAO 1 satellite, between August 1977 until January 1979. The experiment consisted of a collection of collimated sodium iodide scintillators, two of which the Low Energy detectors (LED, LED-3 and LED-6), were optimized for the lower energy part of the hard X-ray range between 13 to 180 keV. The first 6-months of mission were dedicated to an all-sky scan after which a pointing phase started. In pointing mode the A4-LED instrument look axis was kept in a 1 deg dead band centered on the target position. Instead in the "ping-pong" mode the look axis was regularly alternated with a secondary target a few degrees away, usually for background determination. This database table accesses the spectra (and associated files) obtained from the A4-LED detectors in the ping-pong mode. This is a service provided by NASA HEASARC .
79. HEAO 1 A2 Spectra Background
ID:
ivo://nasa.heasarc/a2specback
Title:
HEAO 1 A2 Spectra Background
Short Name:
A2SPECBACK
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The A2 experiment was flown on the HEAO-1 satellite, between August, 1977 until January 1979. The experiment consisted of six multi-layer multi-anode collimated gas proportional counters. These were two LEDs (Low Energy Detectors), a MED (Medium Energy Detector), and three HEDs (High Energy Detectors). The first 6-months of mission were dedicated to an all-sky scan after which a pointing phase started. This database table accesses all the background files available at HEASARC obtained from the A2 MED (small and large field of view) and HEDs (1 and 3 small and large filed of view) detectors during the pointed phase. This is a service provided by NASA HEASARC .
80. Herschel Space Observatory Log of Observations
ID:
ivo://nasa.heasarc/herschllog
Title:
Herschel Space Observatory Log of Observations
Short Name:
HERSCHLLOG
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The Herschel Space Observatory (Herschel) is an ESA (European Space Agency) project with instruments funded by ESA member states. It was operated from May 2009 till April 2013, offering unprecedented observational capabilities in the far-infrared and sub-millimeter spectral range (55-671 microns [um]). Herschel carried a 3.5m diameter passively cooled Cassegrain telescope, which was the largest of its kind and utilizes a novel silicon carbide technology. The science payload comprised three instruments: two direct detection cameras/medium resolution spectrometers, the Photodetector Array Camera and Spectrometer (PACS) and the Spectral and Photometric Imaging Receiver (SPIRE), and a very high-resolution heterodyne spectrometer, the Heterodyne Instrument for the Far Infrared or HIFI, whose focal plane units were housed inside a superfluid helium cryostat. PACS comprised two mutually exclusive sub-instruments: a bolometric camera designed to perform photometry in three spectral bands (70, 100 and 160 um) and an integral field unit grating spectrometer operating over the spectral range from 57 to 210 um with a spectral resolution ranging from 1000 to 5000. SPIRE comprised a three-band photometer, operating in spectral bands centered on 250, 350 and 500 um, and an imaging Fourier-Transform Spectrometer (FTS), which provided low resolution spectra over the 195-670 um band. Both instruments used germanium bolometers operating at 0.3 K and coupled to the telescope with hexagonally conical feedhorns. The photometer and the spectrometer were not designed to operate simultaneously. HIFI was designed to obtain spectra with very high resolution (up to 10<sup>7</sup>) in the far-infrared and sub-millimeter wavelengths not directly observable by ground-based telescopes. The HIFI instrument was an heterodyne receiver which provided spectroscopy in the continuous frequency range 480-1250 GHz (240-625 microns) and in the frequency range 1410-1910 GHz (157-213 microns). Herschel had two Announcement of Opportunities (AOs) for Open Time (OT) observations. The first in-flight AO for Open Time (OT1) was opened on 20 May 2010, with a deadline of 22 July 2010. For OT1, 241 observing programs were accepted and the total allocated observing time amounts to 6576.9 hours. The second in-flight AO for Open Time (OT2) was opened on 9 June 2011, with a deadline of 15 September 2011. There were parallel AOs for Guaranteed Time observations, GT1 and GT2, with separate deadlines. The Announcement of Opportunity (AO) for Herschel Key Programs (KP) was issued on 1 February 2007, with separate deadlines for guaranteed time (GT) and open time (OT) proposals. The whole Key Program AO process has now been completed, and by coincidence there were exactly the same number of KP GT and OT programs, in both cases 21 programs were awarded observing time. Taken together, these 42 observing programs contained 11,650 astronomical observation requests or AORs (AORs are the primary units of Herschel observing time and are effectively the Herschel 'observation units'). The total allocated observing time for these programs was 11,257.7 hours, corresponding to approximately 57% of the nominally available Herschel routine mission science time. Herschel successfully made over 37,000 scientific observations before its helium cryogen was exhausted. The HSA is available at the Herschel Science Centre at <a href="http://herschel.esac.esa.int/Science_Archive.shtml">http://herschel.esac.esa.int/Science_Archive.shtml</a>, the Herschel help desk is at <a href="http://herschel.esac.esa.int/esupport/">http://herschel.esac.esa.int/esupport/</a>, the Herschel User Provided Data Products are available at <a href="http://herschel.esac.esa.int/UserProvidedDataProducts.shtml">http://herschel.esac.esa.int/UserProvidedDataProducts.shtml</a>, the Herschel Postcard Server is at <a href="http://archives.esac.esa.int/hsa/aio/doc/postcardGallery.html">http://archives.esac.esa.int/hsa/aio/doc/postcardGallery.html</a>, and the Herschel Observation Log is at<a href="http://herschel.esac.esa.int/logrepgen/observationlist.do">http://herschel.esac.esa.int/logrepgen/observationlist.do</a> This table was created by the HEASARC in October 2013 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VI/139">CDS Catalog VI/139</a> file herschel.dat. This is a service provided by NASA HEASARC .