Search

Your search keyword '"X-ray astronomy -- Observations"' showing total 163 results
Start Over "X-ray astronomy -- Observations"

Refine your results

more »

more »

more »

more »

more »

more »
163 results on '"X-ray astronomy -- Observations"'

51. The case of the disappearing gas

Author

Shields, Joseph C.

Subjects
Stars, X-ray astronomy -- Observations, Astronomy
Abstract

The gaseous matter between clusters of galaxies collides, producing strong x-rays, and this results in cooling of the gases. The cool gas condenses into cold gas clouds, which condenses further to form stars. Observations show that the amount of cool mass does not match the rate of cooling. The missing mass has not yet been detected. The presence of some absorbing matter such as dust grains and a diffused warm medium may account for the missing mass.

Published
1995

52. Low-energy galactic-centre gamma rays from low-mass X-ray binaries

Author

Kluzniak, W., Ruderman, M., Shaham, J., and Tavani, M.

Subjects
Galactic center -- Observations, Gamma ray astronomy -- Observations, X-ray astronomy -- Observations, Environmental issues, Science and technology, Zoology and wildlife conservation
Published
1988

54. Spin-down of the X-ray pulsar GX1+4 during an extended low state

Author

Makishima, K., Ohashi, T., Sakao, T., Dotani, T., Inoue, H., Koyama, K., Makino, F., Mitsuda, K., Nagase, F., Thomas, H.D., Turner, M.J.L., Kii, T., and Tawara, Y.

Subjects
Neutron stars -- Observations, X-ray astronomy -- Observations, Pulsars -- Observations, Environmental issues, Science and technology, Zoology and wildlife conservation
Published
1988

55. Is N44C a fossil X-ray ionized nebula?

Author

Pakull, Manfred W. and Motch, Christian

Subjects
Nebulae -- Observations, X-ray astronomy -- Observations, Environmental issues, Science and technology, Zoology and wildlife conservation
Published
1989

56. X-ray emission from the ring nebula NGC6888

Author

Bochkarev, N.G.

Subjects
X-ray astronomy -- Observations, Nebulae -- Observations, Environmental issues, Science and technology, Zoology and wildlife conservation
Published
1988

57. Gamma-rays and X-rays from SN1987A

Author

Leising, Mark D.

Subjects
Gamma ray astronomy -- Observations, Supernovae -- Observations, X-ray astronomy -- Observations, Environmental issues, Science and technology, Zoology and wildlife conservation
Published
1988

58. Weighing a black hole

Subjects
Black holes (Astronomy) -- Research, X-ray astronomy -- Observations -- Research, Astronomy, Observations, Research
Abstract

Most astronomers agree that a neutron star cannot contain more than 3 solar masses. Therefore, finding a collapsed stellar object with a greater mass should prove the existence of a [...]

Published
1993

60. The twin quasar's X-ray counterpart

Subjects
Harvard-Smithsonian Center for Astrophysics -- Research, Quasars -- Observations, Gravitational lenses -- Observations, X-ray astronomy -- Observations
Published
1991

63. Photon bubbles put X-ray fizz into neutron stars

Author

Glanz, James

Subjects
Rossi X-Ray Timing Explorer (Artificial satellite) -- Observations, Observations, Research, X-ray astronomy -- Observations -- Research, Neutron stars -- Research
Abstract

Above the atmosphere, most stars are fairly constant beacons, but star-sized x-ray sources pulse, oscillate, and flash. Theorists thought they were. starting to understand why, but results from a new [...]

Published
1996

64. A split-personality x-ray beacon tantalizes theorists

Author

Glanz, James

Subjects
Observations, X-ray astronomy -- Observations, Neutron stars -- Observations
Abstract

X-ray astronomers are burning the candle at both ends these days, thanks to the appearance of a bizarre and brilliant x-ray emitter that is doing its own kind of double [...]

Published
1996

65. X-rays make a smooth move

Author

Appenzeller, Tim

Subjects
Observations, Extraterrestrial radiation -- Observations, X-ray astronomy -- Observations, Galaxies -- Observations
Abstract

The night sky,, seemingly serene, is abuzz with signals from our cosmic neighborhood: light, radio waves, and other radiation from stars and gas within our galaxy. This cosmic buzz tends [...]

Published
1994

66. High-energy astrophysics

Subjects
Observations, Equipment and supplies, X-ray astronomy -- Observations -- Equipment and supplies, Gamma ray astronomy -- Observations -- Equipment and supplies, Astronomy -- Equipment and supplies, Ultraviolet astronomy -- Observations -- Equipment and supplies
Abstract

The New Year begins auspiciously for astronomers. The shuttle mission to repair the Hubble Space Telescope (HST) could not have gone better, and that success is as valuable to NASA [...]

Published
1994

67. X-rays of 13,500 million-year-old quasars captured by a European Space Agency satellite suggest that the universe is older than previously thought--or that unknown 'iron factories' litter the universe--because quasars contain over three times more iron than our solar system. (Space)

Author

Amodeo, Chris

Subjects
European Space Agency -- Observations, X-ray astronomy -- Observations -- Research, Quasars -- Observations -- Research, Stars -- Research, Cosmology -- Research, Geography, Observations, Research
Abstract

X-rays of 13,500 million-year-old quasars captured by a European Space Agency satellite suggest that the universe is older than previously thought--or that unknown `iron factories' litter the universe--because quasars contain [...]

Published
2002

68. X-ray universe: quasar's jet goes the distance

Author

Cowen, R.

Subjects
Chandra X-ray Observatory (Artificial satellite) -- Observations, Radio sources (Astronomy) -- Observations, X-ray astronomy -- Observations, Jets -- Observations, Quasars -- Observations, Science and technology, Observations
Abstract

Photons left over from the birth of the universe appear to have helped generate the longest X ray-emitting jet ever found in a distant galaxy. Discovered by NASA's Chandra X-ray [...]

Published
2002

69. X-ray craft sees Venus in whole new light. (Science News of the week)

Author

Cowen, R.

Subjects
Venus (Planet) -- Observations, X-ray astronomy -- Observations, Science and technology, Observations
Abstract

Astronomers have unveiled the first X-ray image of Venus, one of Earth's closest neighbors. The observations, taken by the Earth-orbiting Chandra X-ray Observatory and released last week, may provide new [...]

Published
2001

70. Timing a neutron star's hotspot

Author

Schilling, Govert

Subjects
X-ray astronomy -- Observations, Neutron stars -- Observations, Astronomy, Observations
Abstract

WHILE LARGE X-RAY TELESCOPES SUCH AS NASA's Chandra X-ray Observatory and the European XMM-Newton satellite get lots of news attention, a small Italian-Dutch satellite has solved an important problem in [...]

Published
2001

71. Yohkoh captures a solar flare

Author

Appenzeller, Tim

Subjects
Yohkoh (Artificial satellite) -- Observations, Observations, X-ray astronomy -- Observations, Solar flares -- Observations
Abstract

It may not look like the sun, but the image at right shows what the Japanese satellite Yohkoh saw when it trained its instruments on the sun's surface just 2 [...]

Published
1991

72. Advanced satellite for cosmology and astrophysics

Author

McDowell, Jonathan

Subjects
X-ray astronomy -- Observations -- Reports, Artificial satellites, Japanese -- Accidents -- Reports, Astronomy, Accidents, Observations, Reports
Abstract

Japan's ASCA X-ray astronomy satellite (also named Asuka in Japanese) has fallen victim to the biggest solar flare in a decade. After the July 14th blast, Earth's uppermost atmosphere ballooned [...]

Published
2000

74. X-rays of the stars

Author

Thomsen, Dietrick E.

Subjects
Astronomy -- Observations, Stars -- Observations, X-ray astronomy -- Observations, Artificial satellites -- Observations
Published
1981

75. X-ray flashes illuminate general relativity

Author

Peterson, Ivars

Subjects
General relativity (Physics) -- Observations, X-ray astronomy -- Observations, Neutron stars -- Observations, Science and technology, Observations
Abstract

Observations of rapid oscillations in the intensity of X rays emitted by gas striking a neutron star's surface provide a novel test of Einstein's general theory of relativity. A typical [...]

Published
1998

76. X rays reveal black hole dining habits

Author

Cowen, Ron

Subjects
Black holes (Astronomy) -- Observations, X-ray astronomy -- Observations, Galaxies -- Observations, Quasars -- Observations, Science and technology, Observations
Abstract

From arsenic to zinc, black holes gobble up every element within their grasp. Even among such undiscriminating diners, some have bigger appetites than others. Researchers report that for the first [...]

Published
1997

77. X rays and comets

Author

Cowen, Ron

Subjects
X-ray astronomy -- Observations -- Spectra, Comets -- Spectra, Science and technology, Observations, Spectra
Abstract

Last spring, when astronomers detected an X-ray glow surrounding Comet Hyakutake, theorists scurried to explain the unexpected finding (SN: 6/1/96, p. 346). The ROSAT and Extreme Ultraviolet Explorer satellites have [...]

Published
1997

78. Astro eyes new signs of black holes

Author

Cowen, Ron

Subjects
Astro-1 (Artificial satellite) -- Observations, Black holes (Astronomy) -- Observations -- Research, X-ray astronomy -- Observations -- Research, Ultraviolet astronomy -- Research, Science and technology, Observations, Research
Abstract

Astro Eyes New Signs of Black Holes Overcoming a series of technical calamities that threatened to dim its view of the X-ray and ultraviolet universe, the Astro Observatory aboard the [...]

Published
1990

80. The shifting centre

Author

Trimble, Virginia

Subjects
Infrared astronomy -- Observations, Neutrino astrophysics -- Research, Radio sources (Astronomy) -- Observations, X-ray astronomy -- Observations, Environmental issues, Science and technology, Zoology and wildlife conservation
Published
1988

81. M15's X-ray binary

Subjects
Stars, Double -- Research, X-ray astronomy -- Observations
Published
1988

82. The 200-second quasar

Subjects
Quasars -- Observations, X-ray astronomy -- Observations
Published
1982

84. Cygnus X-1: a new clue

Subjects
Black holes (Astronomy) -- Observations, X-ray astronomy -- Observations, X-rays -- Usage, Stars -- Observations
Published
1983

85. Forming a galaxy

Subjects
X-ray astronomy -- Observations, Astronomy -- Observations, Interstellar matter -- Observations, Galaxies -- Evolution
Published
1986

88. Hark, the heavenly noisar

Author

Rensberger, Boyce

Subjects
Stars -- Observations, X-ray astronomy -- Observations
Published
1986

90. Structure of a ring nebula

Author

Raymond, J.C.

Subjects
Nebulae -- Observations, X-ray astronomy -- Observations, Environmental issues, Science and technology, Zoology and wildlife conservation
Published
1988

91. Twinkle, twinkle, X-ray source

Subjects
Astronomical research -- Observations, X-ray astronomy -- Observations, Satellites -- Observations
Published
1981

92. Keeping up with Cygnus X-3

Subjects
Radio sources (Astronomy) -- Observations, X-ray astronomy -- Observations, Cygnus X-3 (Star) -- Observations
Published
1987

93. Ultrafast binary star

Subjects
Stars, Double -- Rotation, X-ray astronomy -- Observations
Published
1987

94. And a pulsar in a supernova remnant

Subjects
Pulsars -- Research, Radio sources (Astronomy) -- Observations, Supernovae -- Research, X-ray astronomy -- Observations
Published
1982

95. Gravity theory: Moffat 2, Einstein?

Author

Thomsen, Dietrick E.

Subjects
Relativity (Physics) -- Research, X-ray astronomy -- Observations, Gravity -- Research
Published
1982

96. X-ray 'ridge' in galactic center

Author

Thomsen, Dietrick E.

Subjects
X-ray astronomy -- Observations, Galaxies -- Observations, Science and technology, Observations
Abstract

The more ways astronomers look at the center of our galaxy the more curious things they find. This time, an-ray survey of the center of the galaxy using the satellite [...]

Published
1985

97. X-ray fireworks put on a stellar show

Author

Peterson, I.

Subjects
Cygnus (Constellation) -- Observations, X-ray astronomy -- Observations, Stars, Double -- Observations, Science and technology, Observations
Abstract

X-ray fireworks put on a stellar show Astronomers have detected a new, surprisingly strong source of X-rays, which appear to come from a pair of stars in the constellation Cygnus. [...]

Published
1989

99. Preliminary results from a high-pressure imaging spectroscopic proportional counter.

Author

Hall, C. J., Bazzano, A., Lewis, R. A., Parker, B., Ubertini, P., and Worgan, J. S.

Subjects
PROPORTIONAL counters, RADIOACTIVITY instruments
Abstract

A new type of high-pressure proportional counter, with both spatial resolution and spectroscopic capabilities is being jointly developed by the Istituto di Astrofisica Spaziale (CNR), Frascati, Italy and the SERC Daresbury Laboratory, Warrington, UK. The characteristics of the detector can be optimized for the particular requirement of the experiment, either for x-ray astronomy observations from space, or for the high count rate applications associated with a synchrotron light source. In its baseline configuration, the detector is filled to 5 bar with a xenon/quench gas mixture and will be sensitive over the energy range 5 key to 150 keV (2.5 to 0.08 Å). The positional resolution will range from 500 μm at the lower energies to around 1 mm at the higher end of the. energy range. The current prototype has a sensitive area of 200 × 200 mm. The final version is hoped to have an area closer to 425 × 425 mm. The very small photon absorption length in the higher pressure gas allows the parallax effect, a feature of 1 atmosphere detectors, to be greatly reduced. The timing resolution (150 ns) of the detector enables both a high-rate capability and the possibility of the escape gate technique to achieve higher spectral resolution at energies > the Xe K edge. Preliminary results are presented showing the spectral and positional resolution for the prototype detector. [ABSTRACT FROM AUTHOR]

Published
1992
Full Text
View/download PDF

100. Astronomical x-ray polarimetry based on photoelectric effect with microgap detectors

Author

Soffitta, Paolo, Costa, Enrico, di Persio, Giuseppe, Morelli, Ennio, Rubini, Alda, Bellazzini, Ronaldo, Brez, Alessandro, Raffo, Renzo, Spandre, Gloria, Joy, David, Soffitta, Paolo, Costa, Enrico, di Persio, Giuseppe, Morelli, Ennio, Rubini, Alda, Bellazzini, Ronaldo, Brez, Alessandro, Raffo, Renzo, Spandre, Gloria, and Joy, David

Abstract

The polarisation of x-ray photons can be determined by measuring the direction of emission of a K-shell photoelectron. Effective exploitation of this effect below 10 keV would allow development of a highly sensitive x-ray polarimeter dedicated in particular to x-ray astronomy observations. Only with the advent of finely segmented gas detectors was it possible to detect polarisation sensitivity based on the photoelectric effect in this energy range. Simulation and measurements at 5.4 and 8.04 keV with a microgap gas counter, using both a polarised and an unpolarised x-ray source, showed that the photoelectron track in a neon-based gas mixture retains the memory of the polarisation of the incoming photons. Possible experiments aimed at galactic/extragalactic sources and solar flares are considered and their sensitivity to these sources is calculated., Comment: 45 pages included 13 figures; (Accepted for publication in : Nuclear Instruments and Methods in Physics Research A)

Published
2000
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results