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A Brief History of High-Energy Astronomy: 1990 - 1994
In Reverse Chronological Order
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Nov 1, 1994 |
Launch of
GGS-WIND carrying the Transient Gamma Ray Spectrometer (TGRS)
and the Konus gamma-ray burst instrument (still operational). |
Oct 11, 1994 |
Termination of the
Magellan mission to Venus when the spacecraft entered the Venusian
atmosphere; the primary goal of this mission was to make
the most highly detailed maps of this planet ever using a sophisticated
imaging radar. |
Jul 16 - 22 1994 |
Detection of X-rays triggered by the impact on the planet Jupiter of
fragments of Comet Shoemaker/Levy 9 by the ROSAT HRI instrument. Unlike
in the optical and infrared where the brightenings occurred at the impact site
in Jupiter's southern hemisphere, the X-ray brightenings occurred in Jupiter's
auroral regions in its high northern latitudes, for reasons which are still
not completely understood. See Waite et al. (1995, Science, 268, 1598) for
more details about this observation. |
Dec 23, 1993 |
End of scientific operations of the
COsmic Background Explorer
(COBE), a NASA mission whose primary goals were
to study the spectrum and anisotropy of the cosmic 3 degree K background in the
energy band from 0.1 to 10 mm, and the spectrum and angular distribution of
the diffuse infrared background in the IR and far-IR bands (1 to 300 microns).
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Aug 21, 1993 |
Destruction by an explosion in the rocket propulsion system of
Mars Observer as
it attempted to maneuver into a Martian orbit. It is the first
interplanetary probe lost by NASA. Lost with it is the onboard gamma-ray burst
(GRB) detector that had formed part of the interplanetary
GRB detector network consisting of Mars Observer, the
Compton Gamma Ray Observatory,
and the Ulysses
solar probe. |
Jun 23, 1993 |
Recovery of the
European Retrievable Carrier (EURECA) free-flyer by the Space
Shuttle Endeavor (STS-57) after it had spent almost 11 months in low-Earth
orbit (LEO). The EURECA satellite carried a number of experiments
designed to conduct microgravity
studies, solar observations, and material technology investigations. Also
on board was the WATCH or Wide Angle Telescope for Cosmic Hard X-rays
instrument which gradually scanned across most of the sky during its
mission lifetime. |
Apr 25, 1993 |
Launch of the
Array of Low Energy X-ray Imaging Systems (ALEXIS) satellite.
This US Department of Energy (DOE) mini-satellite contains six compact
normal-incidence ultrasoft X-ray or extreme-ultraviolet
(EUV) telescopes operating in narrow bands centered on energies of 0.066,
0.071, and 0.095 keV (still operational). |
Mar 28, 1993 |
Discovery of the Supernova 1993J in the Messier 81 Galaxy,
the second brightest supernova observed in the twentieth century.
This Type IIb supernova had a prompt peak in its optical brightness on
March 30, followed by a rapid decline, and then a gradual rise to a second
peak on April 18. It was detected as an X-ray source by the ROSAT X-ray
Observatory in an initial observation on April 3, and follow-up observations
by the ROSAT and ASCA satellites showed a slow and steady decline in its
X-ray flux over the next year or so. SN 1993J was also detected as a soft
gamma-ray (50 - 150 keV) source by the Compton Observatory OSSE instrument
12 days and then 1 month after its discovery. See the papers by Zimmermann et
al. (Nature, 367, 621, 1994), Uno et al. (ApJ, 565, 419, 2002) and Leising
et al. (ApJ, 431, L95) on the ROSAT, ASCA, and OSSE observations,
respectively. |
Feb 20, 1993 |
Launch of the fourth Japanese X-ray astronomy satellite,
Advanced Satellite for
Cosmology and Astrophysics (ASCA), known as Astro-D prior to its
launch. |
Jan 31, 1993 |
Detection of an intense gamma-ray burst (GRB) by the instruments
on the Compton Gamma-Ray Observatory (CGRO) at 18:57:12 UT. This GRB was
arguably the brightest GRB observed by CGRO, with a peak flux of 105 photons
s-1 cm-2. Because the date on which it occurred was
also that of the Superbowl, this GRB has become known (at least in the US)
as the `Superbowl Burst' since it occurred on the same day as
the 1993 National Football League Superbowl. |
Oct 8, 1992 |
Pioneer Venus Orbiter
enters the Venusian atmosphere. At the time of its demise, the
Orbiter had
been a functioning anchor in various interplanetary gamma-ray burst
detection networks for over 14 years. |
Sep 25, 1992 |
Launch of NASA's ill-fated
Mars Observer
spacecraft. |
Aug 2, 1992 |
Release of ESA's European
Retrievable Carrier (EURECA) free-flying satellite from the Space
Shuttle Atlantis (STS-46). |
Jul 1992 |
The Gamma satellite
ceases operations. This Soviet-led mission had as its principal
instrument the Gamma-1 telescope, a gamma-ray detector sensitive to
gamma-rays with energies from 50 MeV to 6 GeV. |
Jun 7, 1992 |
Launch of NASA's
Extreme UltraViolet Explorer (EUVE). |
May 21 & 28, 1992 |
Publication dates of the discovery of soft X-ray pulsations from the
hithertoo mysterious gamma-ray source called Geminga by Halpern and Holt
(Nature, 357, 222, 1992), based on ROSAT observations, and of
gamma-ray pulsations from the same source by Bertsch et al. (Nature,
357, 306, 1992), based on CGRO EGRET observations. Geminga
(aka 2CG 195+04) was the second
brightest gamma-ray source in the >=100 MeV band that had been detected by the
COS-B satellite, but its
nature had remained unclear until this discovery of 237 millisecond pulsations
confirmed some previous suggestions that it was, like Vela, a gamma-ray
pulsar. |
Late 1991/Early 1992 |
Definitive detection of soft (0.5-2.0 keV) X-ray emission from the
supernova SN 1987A, by the imaging ROSAT PSPC detector. Earlier observations
by the (non-imaging) Ginga LAC detectors had suggested the existence of a
soft X-ray (in addition to hard X-ray) emission, but an earlier short ROSAT
observation in Jun 1990 had failed to detect any such emission at the position
of the supernova. This soft X-ray emission is believed to be qualitatively
different than the hard X-ray emission (produced by Compton downscattering
of the Cobalt 56 gamma-ray emission lines) and to be due to thermal emission
by plasma in the pre-existing circumstellar material which is being shock-heated
by the supernova blast wave. See Gorenstein et al. (ApJ, 420, L25, 1994) and
Beuermann et al. (A&A, 281, L45, 1994) for more details. |
Nov 1, 1991 |
Ginga, the third Japanese X-ray
astronomy satellite (ASTRO-C), ceases operation. |
Oct 15, 1991 |
Detection of a cosmic ray particle (or, less likely, a gamma-ray photon
or a strangelet) with the highest ever recorded energy
of 3.2 x 1020 eV (or 5 x 108 erg, equivalent to the
kinetic energy of a 1 kilogram rock moving at a speed of 10 meters per second!)
by the University of Utah's Fly's Eye I fluorescence detector. Because of its
high energy and the effect of the cosmic microwave background radiation on such
an energetic particle (the `Greisen-Zatsepin-Kuzmin or GZK Cut-off'), if this
event were due to a cosmic ray, it must have originated from a
source no more than 30 Megaparsecs distant. See Bird et al.
(ApJ, 441, 144, 1995) for a detailed report on this event and O'Halloran
et al. (Physics Today, January 1998, p. 31) for a review of the highest energy
cosmic rays and other references. The physics of cosmic rays is discussed at a
popular level at the Cosmic
and Heliospheric Learning Center. |
Apr 21, 1991 |
Detection of a short burst of gamma-rays from the direction of the
Earth, by the BATSE instrument on board the
Compton Gamma Ray Observatory (CGRO): see Fishman et al. (Science, 264,
1313, 1994) for more details. This was the first of 75 so-called
Terrestrial Gamma Flashes (TGFs) discovered by CGRO; they are
generally believed to be emission from highly relativistic electrons
generated by strong electric fields in the Earth's mesosphere associated with
thunderstorms, although alternate suggestions have been proposed, e.g., that
they are due to ultra-high-energy neutrinos which have passed through the
Earth and then interacted with the atmosphere to produce
upward-directed air showers (see Fargion, ApJ, 570, 909, 2002). |
Apr 5, 1991 |
Deployment of NASA's
Compton
Gamma-Ray Observatory (CGRO) by the Space Shuttle Atlantis
(STS-37). |
Mar 30, 1991 |
First Detection of X-Ray emission close to the peak of a classical nova
outburst, by the ROSAT Position Sensitive Proportional Counter (PSPC).
Nova Herculis 1991 was discovered by optical observers on 1991 March 24-25
near or just after its 5th magnitude maximum. It was observed by ROSAT five
days later, and detected as a `hard' X-ray source with an inferred
temperature of >=108K interpreted to be due to shocked
circumstellar material. See Lloyd et al. (Nature, 356, 222, 1992) for
more details about this discovery. |
Dec 2, 1990 |
Launch of the Space Shuttle Columbia (STS-35) carrying the
Astro 1 payload.
Astro 1 included three UV telescopes (UIT, HUT, & WUPPE) and
the Broad Band X-Ray
Telescope (BBXRT). |
Nov 1990 |
Establishment of the High Energy
Astrophysics Science Archive Research Center (HEASARC) at NASA's
Goddard Space Flight Center (GSFC). |
Oct 6, 1990 |
Launch of the joint NASA/ESA Ulysses mission,
from the Space Shuttle Discovery (STS-41). This satellite carries
a solar X-ray and cosmic gamma-ray burst experiment. (still
operational). |
Jul 11, 1990 |
Launch of the Russian
Gamma satellite. This Soviet-led mission had as its principal
instrument the Gamma-1 telescope, a gamma-ray detector sensitive to
gamma-rays with energies from 50 MeV to 6 GeV. |
Jun 29, 1990 |
Detection by the Röntgen
Satellit (ROSAT) of X-ray emission from
the Moon. This was
the first X-ray detection of the Moon by a satellite in Earth orbit (X-rays
had previously been detected by detectors on Apollo spacecraft while
in lunar orbit), and the implied X-ray luminosity of 7 x 1011
erg s-1 was 1015 times smaller than that of the Sun.
The X-rays were interpreted as being due to back-scattering of solar X-rays
(see Schmitt et al. 1991, Nature, 349, 583 for more details). Interestingly,
the modern age of X-ray astronomy began in a flight made 28 years previous
to this on Jun 18 1962 whose
(unsuccessful) aim was to detect such scattered solar X-rays from the Moon
(it instead detected the first extrasolar X-ray source, Sco X-1, and the
X-ray background).
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Jun 1, 1990 |
Launch of Röntgen
Satellit (ROSAT), an X-ray and EUV astronomy mission due to an
international collaboration between Germany, the UK, and the US. This mission
had two phases, an All-Sky Survey phase from the end of July 1990 until
February 1991 in which the spinning satellite
mapped the entire sky in both X-rays and the EUV (and detected more than 100,000
discrete X-ray sources), and a pointed observation phase in which the satellite
could make deep observations of selected positions in the sky. |
Apr 18, 1990 |
Launch of the Hubble Space
Telescope (HST). The HST is a 2.4-meter reflecting telescope
which was deployed in low-Earth orbit (600 kilometers above the surface of the
Earth) by the crew of the space shuttle Discovery in mission STS-31 on
25 April 1990. HST's instruments have been serviced and/or replaced several
times and can observe in the ultraviolet, visible light, and near-infrared
spectral regions. (still operational). |
Acknowledgements
We would like to thank the following individuals for their
contributions to this page:
Jesse S. Allen, and
Ian M. George
along with
JPL's Space Calendar and the
Working Group for the History of Astronomy's
Astronomiae Historia (History of Astronomy) information pages.
Return to main History
of High-Energy Astronomy page
Web page author: Stephen A. Drake (based on an original by Jesse S. Allen)
Web page maintainer: Stephen A. Drake
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