Search

Your search keyword '"PACIESAS, W.S."' showing total 37 results
Start Over Author "PACIESAS, W.S."
37 results on '"PACIESAS, W.S."'

1. Limits on hard x-ray emission from the Comet Shoemaker-Levy 9 impact on Jupiter

Author

Rubin, Brad C., Fishman, G.J., Harmon, B.A., Waite, J.H., Jr., Link, R., Zhang, S.N., Brainerd, J.J., Pendleton, G.N., Meegan, C.A., and Paciesas, W.S.

Subjects
Proton-induced X-ray emission -- Research, Shoemaker-Levy 9 (Comet) -- Observations, Jupiter (Planet) -- Atmosphere, Comets -- Research, Astronomy, Earth sciences
Abstract

Data from the burst and transient source experiment (BATSE) onboard the Compton Gamma-Ray Observatory (CGRO) have been used to set upper limits on emission in the 20-1800 keV energy range from the collision of Comet Shoemaker-Levy 9 with Jupiter. For an impulsive event of 1 sec duration we place a 4 sigma upper limit on the equivalent isotropic energy release of 5 x [10.sup.20] ergs in the 20-50 keV energy band. The upper limit on steady emission observed during the week of the collision is 2 x [10.sup.19] erg/sec (20-50 keV). We discuss the implications of these observations for impact effects on the jovian atmosphere.

Published
1996

2. Correlation between X-ray outbursts and relativistic ejections in the X-ray transient GRO J1655 - 40

Author

Harmon, B.A., Wilson, C.A., Zhang, S.N., Paciesas, W.S., Fishman, G.J., Hjellming, R.M., Rupen, M.P., Scott, D.M., Briggs, M.S., and Rubin, B.C.

Subjects
X-rays -- Analysis, Radio waves -- Analysis, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

X-ray emission from relativistic jet sources usually proceeds radio relativistic jets by between a few days and two weeks despite the belief that the emissions feed the source with the material necessary to produce the jet. Therefore, the mechanism by which the X-ray emissions are connected to the ejection method must be complex. GRO J1655 - 40, an object/accretion-disk system, may help resolve some of the questions about jet formation and its connection to X-ray emission.

Published
1995

3. A maskless gamma-ray all-sky imager: BATSE/CGRO

Author

Zhang, S.N., Fishman, G.J., Harmon, B.A., Paciesas, W.S., Meegan, C.A., Wilson, R.B., Finger, M.H., and Rubin, B.C.

Subjects
Nuclear counters -- Usage, Gamma rays -- Measurement, Business, Electronics, Electronics and electrical industries
Abstract

The non-collimated detectors of BATSE (Burst And Transient Source Experiment) on the Compton Gamma Ray Observatory (CGRO) can be used as a high sensitivity hard X-ray and low energy gamma-ray all-sky imager in the energy range between 20 keV and 2 MeV. The fluxes from sources in the sky are modulated as the spacecraft orbits the Earth. The CGRO orbital precession further allows sampling of sky in strips corresponding to the limb of the earth at any given time. The modulation data are transformed into images by various reconstruction methods. High sensitivity images of location accuracy of about 0.1 [degree] and source separation of about 1 [degree] are obtained.

Published
1994

4. Discovery of intense gamma-ray flashes of atmospheric origin

Author

Fishman, G.J., Bhat, P.N., Mallozzi, R., Horack, J.M., Koshut, T., Kouveliotou, C., Pendleton, G.N., Meegan, C.A., Wilson, R.B., Paciesas, W.S., Goodman, S.J., and Christian, H.J.

Subjects
Thunderstorms -- Research, Atmospheric radiation -- Research, Gamma rays -- Research, Science and technology, Research
Abstract

Detectors aboard the Compton Gamma Ray Observatory have observed an unexplained terrestrial phenomenon: brief, intense flashes of gamma rays. These flashes must originate in the atmosphere at altitudes above at least 30 kilometers in order to escape atmospheric absorption and reach the orbiting detectors. At least a dozen such events have been detected over the past 2 years. The photon spectra from the events are very hard (peaking in the high-energy portion of the spectrum) and are consistent with bremsstrahlung emission from energetic (million-electron volt) electrons. The most likely origin of these high-energy electrons, although speculative at this time, is a rare type of high-altitude electrical discharge above thunderstorm regions., We report here the detection of high-energy photons from the Earth's upper atmosphere, observed with the multiple detectors of the Burst and Transient Source Experiment (BATSE) (1) on the Compton [...]

Published
1994

5. The rarity of soft gamma-ray repeaters deduced from reactivation of SGR1806-20

Author

Kouveliotou, C, Fishman, G. J, Meegan, C. A, Paciesas, W.S, Paradijs, J. Van, Norris, J. P, Preece, R. D, Briggs, M. S, Horack, J. M, Pendleton, G. N, and Green, D.A

Subjects
Space Radiation
Abstract

Only two different types of gamma-ray transient sources are presently known: over one thousand Gamma-Ray Bursters (GRBs) and only three Soft Gamma-Ray repeaters (SGRs). The latter are distinguished by their propensity for recurrent burst behaviour, in contrast to the nonrepeating GRB sources. Recurrent emission from one of the repeaters, SGR1900 + 14, has been detected earlier by the Burst and Transient Source Experiment (BATSE) aboard the Compton Gamma-Ray Observatory. Here we report renewed burst activity from SGR1806 - 20, the most prolific of the three known SGRs. This detection of reactivation of this source has been rapidly followed by identification of an X-ray counterpart, which also coincides with a compact radio source now identified as a plerionic (pulsar-powered) supernova remnant. In combination, these results are leading to a convergence of ideas about the nature of SGRs, which can now be firmly identified as neutron stars. That BATSE has detected no new sources in its two and a half years of operation indicates that SGRs are rare in our Galaxy.

Published
1994

6. BATSE observations of 3C273

Author

Paciesas, W.S, Mallozzi, R. S, Pendleton, G. N, Harmon, B. A, Wilson, C. A, Zhang, S. N, and Fishman, G. J

Subjects
Astronomy
Abstract

The quasar 3C273 has been detected by all instruments on CGRO. The emission from this source is monitored continuously by BATSE using Earth occultation. We present results of a preliminary analysis of BATSE data, including light curves of the 3C273 flux covering approximately 150 days in the interval April-August 1991 and approximately 350 days in the interval July 1992-April 1993. The source intensity in the energy range 50-300 keV is typically approx. 0.002 ph cm(exp -2)s(exp -1). We find weak evidence for variations of as much as a factor of 3 in the intensity. We derive spectral parameters of 3C273 during the intervals TJD 8422-8435 (15-28 June 1991) and TJD 8532-8546 (3-17 October 1991) for comparison with other CGRO instruments.

Published
1994

8. The rarity of soft gamma-ray repeaters deduced from reactivation of SGR1806 - 20

Author

Kouveliotou, C., Fishman, G.J., Meegan, C.A., Paciesas, W.S., Paradijs, J. van, Norris, J.P., Preece, R.D., Briggs, M.S., Horack, J.M., Pendleton, G.N., and Green, D.A.

Subjects
Gamma rays -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

The soft-gamma ray repeater (SGR), SGR 1806-20, exhibits sudden activity in gamma ray bursts. The SGRs constitute the gamma-ray transient sources in the universe, along with the gamma ray busters (GRB). The SGRs exhibit bursts of gamma rays periodically, while the GRBs do not exhibit gamma ray bursts repeatedly. Gamma ray bursts are identified by the recognition of the X-ray counterpart of these rays. The SGRs may be neutron stars, as indicated by the study of the gamma ray bursts.

Published
1994

9. Searching the Gamma-ray Sky for Counterparts to Gravitational Wave Sources: Fermi GBM and LAT Observations of LVT151012 and GW151226

Author

RACUSIN, J, BURNS, E, GOLDSTEIN, A., CONNAUGHTON, V., WILSON-HODGE, C.A., JENKE, P., BLACKBURN, L., BRIGGS, M, BROIDA, J, CAMP, J, CHRISTENSEN, N., HUI, C M, LITTENBERG, L, SHAWHAN, P, SINGER, L., VEITCH, J, BHAT, P, CLEVELAND, W., FITZPATRICK, G, GIBBY, M, VON KIENLIN, A, MCBREEN, S, MAILYAN, B., MEEGAN, C.A., PACIESAS, W.S., PREECE, R.D., ROBERTS, O.J., STANBRO, M, VERES, P, ZHANG, B.-B, ACKERMANN, M., ALBERT, A., ATWOOD, William B., AXELSSON, Magnus, BALDINI, L., BALLET, Jean, BARBIELLINI, Guido, BARING, Matthew G., BASTIERI, D., BELLAZZINI, R., BISSALDI, E., BLANDFORD, R.D., BLOOM, E.D., BONINO, R., BREGEON, J., BRUEL, Pascal, BUSON, S., CALIANDRO, G.A., CAMERON, R. A., CAPUTO, R., CARAGIULO, M., CARAVEO, P. A., CAVAZZUTI, E., CHARLES, E., CHIANG, J., CIPRINI, S., COSTANZA, F., CUOCO, A., CUTINI, S., D'AMMANDO, F., DE PALMA, F., DESIANTE, R., DIGEL, S. W., LALLA, N. Di, DI MAURO, M., DI VENERE, L., DRELL, P S., FAVUZZI, C., FERRARA, E.C., FOCKE, W.B., FUKAZAWA, Y., FUNK, S, FUSCO, P., GARGANO, F., GASPARRINI, D., GIGLIETTO, N., GILL, G., GIROLETTI, M., GLANZMANN, T., GRANOT, J., GREEN, D., GROVE, J.E, GUILLEMOT, Lucas, GUIRIEC, S., HARDING, A.K., JOGLER, T., JÓHANNESSON, G., KAMAE, T., KENSEI, S., KOCEVSKI, D., KUSS, M., LARSSON, S., LATRONICO, L., LI, J., LONGO, F., LOPARCO, F., LUBRANO, P., MAGILL, J. D., MALDERA, S., MALYSHEV, D., MCENERY, J. E., MICHELSON, P.F., MIZUNO, T., MORSELLI, A., MOSKALENKO, I. V., NEGRO, M., NUSS, E., OMODEI, N., ORIENTI, M., ORLANDO, E., ORMES, J. F., PANEQUE, D., PERKINS, S., PESCE-ROLLINS, M., PIRON, Frédéric, PIVATO, G., PORTER, T.A., PRINCIPE, G., RAINÒ, S., RANDO, R., RAZZANO, M., RAZZAQUE, S., REIMER, A., REIMER, O., SAZ PARKINSON, P.M., SCARGLE, J.D., SGRÒ, C, SIMONE, D, SISKIND, E. J., SMITH, D, SPADA, F, SPINELLI, P, SUSON, D.J., TAJIMA, H, THAYER, J.B, TORRES, D.F, TROJA, E, UCHIYAMA, Y, VIANELLO, G, WOOD, K.S., WOOD, M., NASA Goddard Space Flight Center (GSFC), GSFC Laboratory for High Energy Astrophysics (LHEA), University of Alabama in Huntsville (UAH), Universities Space Research Association (USRA), NASA Marshall Space Flight Center (MSFC), Massachusetts Institute of Technology (MIT), Center for Space Plasma and Aeronomic Research [Huntsville] (CSPAR), Carleton College, Observatoire Royal de Belgique, Department of Physics and Astronomy [Northfield], University of Maryland [College Park], University of Maryland System, University of Birmingham [Birmingham], University College Dublin [Dublin] (UCD), Jacobs Technology ESCG, Max-Planck-Institut für Extraterrestrische Physik (MPE), University College of Dublin, Deutsches Elektronen-Synchrotron [Hamburg] (DESY), Los Alamos National Laboratory (LANL), Santa Cruz Institute for Particle Physics (SCIPP), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), Royal Institute of Technology [Stockholm] (KTH ), Istituto Nazionale di Fisica Nucleare [Pisa] (INFN), Istituto Nazionale di Fisica Nucleare (INFN), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Fisica Nucleare, Sezione di Trieste (INFN, Sezione di Trieste), Department of Physics and Astronomy [Houston], Rice University [Houston], Istituto Nazionale di Fisica Nucleare, Sezione di Padova (INFN, Sezione di Padova), Istituto Nazionale di Fisica Nucleare, sezione di Bari (INFN, sezione di Bari), Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), Stanford University, Istituto Nazionale di Fisica Nucleare, Sezione di Torino (INFN, Sezione di Torino), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica 'M. Merlin' dell'Università e del Politecnico di Bari, Politecnico di Bari, Istituto di Astrofisica Spaziale e Fisica Cosmica - Milano (IASF-MI), Istituto Nazionale di Astrofisica (INAF), Agenzia Spaziale Italiana (ASI) Science Data Center, Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Istituto di Radioastronomia [Bologna] (IRA), UGC-DAE Consortium for Scientific Research, AUTRES, Unité Scientifique de la Station de Nançay (USN), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Hiroshima City University, SLAC National Accelerator Laboratory (SLAC), Open University of Israël, Department of Natural Sciences [Ra'anana}, Naval Research Laboratory (NRL), Friedrich-Alexander-Universität, University of Iceland [Reykjavik], Tokyo University of Science [Tokyo], Institut de Ciencies de l'Espai [Barcelona] (ICE-CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (INFN, Sezione di Perugia), Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tor Vergata (INFN, Sezione di Roma Tor Vergata), Istituto di Radioastronomia INAF, Department of Physics and Astronomy [Denver], University of Denver, Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, PPM Group [University of Johannesburg], Department of Geology [University of Johannesburg], University of Johannesburg [South Africa] (UJ)-University of Johannesburg [South Africa] (UJ), Universität Innsbruck [Innsbruck], NASA Ames Research Center (ARC), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), NYCB Real-Time Computing Inc., Lattingtown, NYCB Real-Time Computing Inc. [Lattingtown], Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Purdue University [West Lafayette], Nagoya University, Department of Physics, Rikkyo University [Tokyo], University of California [Santa Cruz] (UCSC), University of California-University of California, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Dipartimento di Fisica M. MerlinUniversitte del Politecnico di Bari, Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Dipartimento di Fisica \M. Merlin' dell'Universita e del Politecnico di Bari, Science Institute, University of Iceland, Université Montpellier 2 - Sciences et Techniques (UM2), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), University of Johannesburg (UJ)-University of Johannesburg (UJ), Leopold-Franzens Universitat Innsbruck, École normale supérieure - Paris (ENS Paris), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Purdue University Calumet Department of Chemistry and Physics, National Institute for Nuclear Physics (INFN), Stanford University [Stanford], Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université d'Orléans (UO)-Observatoire des Sciences de l'Univers en région Centre (OSUC), PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Stanford Linear Accelerator Center (SLAC), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP)

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), gravitational waves, Astrophysics::High Energy Astrophysical Phenomena, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], FOS: Physical sciences, gamma rays: general, methods: observational, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger event GW151226 and candi- date LVT151012. No candidate electromagnetic counterparts were detected by either the GBM or LAT. We present a detailed analysis of the GBM and LAT data over a range of timescales from seconds to years, using automated pipelines and new techniques for char- acterizing the upper limits across a large area of the sky. Due to the partial GBM and LAT coverage of the large LIGO localization regions at the trigger times for both events, dif- ferences in source distances and masses, as well as the uncertain degree to which emission from these sources could be beamed, these non-detections cannot be used to constrain the variety of theoretical models recently applied to explain the candidate GBM counterpart to GW150914., 27 pages, 1 table, 11 figures, Submitted to ApJ

Published
2017
Full Text
View/download PDF

10. Imaging high-energy astrophysical sources using Earth occultation

Author

Zhang, S.N., Fishman, G.J., Harmon, B.A., and Paciesas, W.S.

Subjects
Occultations -- Research, Gamma ray astronomy -- Observations, Remote sensing -- Equipment and supplies, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

The use of occultation transform imaging method facilitates the imaging of high-energy astrophysical sources. The Compton Gamma-Ray Observatory method uses large area, non-collimated detectors of the Burst and Transient Source Experiment. The earth becomes a stable occulting disk as the spacecraft travels in its orbit, and data from many occultations are changed into an image.

Published
1993

11. Recurrent burst activity from the soft gamma-ray repeater SGR 1900+14

Author

Kouveliotou, C., Fishman, G.J., Meegan, C.A., Paciesas, W.S., Wilson, R.B., Paradijs, J. van, Preece, W.S., Briggs, M.S., Pendleton, G.N., Brock, M.N., Koshut, T.M., and Horack, J.M.

Subjects
Gamma ray astronomy -- Research, Cosmic rays -- Observations, Neutron stars -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

The detection of three short, very soft transient events from the old soft gamma-repeater SGR 1900+14 by the Burst and Transient Source Experiment is reported. Soft gamma-repeaters (SGRs) were considered to be distinct from about 1,000 sources of cosmic gamma-ray bursts because they exhibit recurrent activity. The SGR active phase lasts at least 13 years and, taken together with the supposed galactic origin of SGRs, indicate that SGRs are neutron stars.

Published
1993

12. Spatial distribution of gamma-ray bursts observed by BATSE

Author

Meegan, C.A., Fishman, G.J., Wilson, R.B., Paciesas, W.S., Pendleton, G.N., Horack, J.M., Brock, M.N., and Kouveliotou, C.

Subjects
Gamma ray astronomy -- Research, Cosmic rays -- Measurement, Astrophysics -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Published
1992

13. Simulation Study of COSMIC -- A Compton Telescope All-Sky Monitor Concept for Low-Energy Gamma-Ray Astronomy

Author

Kippen, R.M., Paciesas, W.S., Pendleton, G.N., and Swartz, D.A.

Subjects
Nuclear research -- Observations, Atmospheric research -- Observations, Environmental monitoring equipment -- Research, Business, Electronics, Electronics and electrical industries
Abstract

The highly transient nature of cosmic low-energy gamma-ray sources offers unique insight into the astrophysics of extreme processes. Sensitive, long-term, all-sky monitoring is required to make sense of the variable emission. Instrumentation for such observations must have the combination of large effective collection area, wide field-of-view and good angular resolution. Recent advances in position-sensitive detectors and associated electronics make it possible to consider a multi-scatter Compton telescope, combined with a coded mask, as an all-sky monitor in the energy range ~10 keV to a few MeV. We present simulations of various configurations of such an instrument and show that it can provide a substantial improvement over other sky monitor strategies in this energy regime.

Published
2000

14. RXTE Observations of Cygnus X-3's jet

Author

McCullough, M.L., Robinson, C.R., Zhang, S.N., Harmon, B.A., Paciesas, W.S., Dieters, S., Hjellming, R.M., Rupen, M., Mioduszewski, A.J., Waltman, E.B., Ghigo, F.D., Pooley, G.G., Fender, R.P., Cui, W., Trushkin, S., Bell Burnell, S.J., Ogley, R.N., and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Published
1998

16. GRO J1744-28

Author

Harmon, B.A., van Paradijs, J.A., Paciesas, W.S., Zhang, S.N., Kouveliotou, C., and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Published
1996

17. BASIS: a GRB mission concept

Author

Gehrels, N., Teegarden, B., Barbier, L., Cline, T., Parsons, A., Tueller, J., Barthelmy, S.D., Palmer, D.M., Krizmanic, J., Fenimore, E., Fishman, G.J., Kouveliotou, C., Hurley, K.C., van Paradijs, J.A., Paciesas, W.S., Woosley, S., Leventhal, M., McCammon, D., Sanders, W., Schaefer, B., Briggs, M.F., Fismann, G.J., and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Published
1996

18. Evidence for sub-millisecond structure in a gamma-ray burst

Author

Bhat, P.N., Fishman, G.J., Meegan, C.A., Wilson, R.B., Brock, M.N., and Paciesas, W.S.

Subjects
Gamma ray astronomy -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

A gamma-ray burst (GRB) 910711 has an interval between bursts of only about 8 milliseconds, the shortest duration yet detected by the Burst and Transient Source Experiment (BATSE) aboard the Compton Observatory satellite. Moreover, BATSE's data indicate that GRB910711 is both narrower and is releasing more energy than a light-curve summed of all detectors would suggest. In addition, GRB910711 has a time profile with a marked submillisecond structure which any future GRB theory must account for.

Published
1992

19. Recurrent burst activity from the soft γ-ray repeater SGR 1900+14

Author

Kouveliotou, C. Fishman, G.J. Meegan, C.A. Paciesas, W.S. Wilson, R.B. Paradijs, J.V. Preece, R.D. Briggs, M.S. Pendleton, G.N. Brock, M.N. Koshut, T.M. Horack, J.M.

Abstract

Of the one thousand or so detected sources of cosmic γ-ray bursts (GRBs), only three are known to have exhibited recurrent activity1-4. These events differ from the majority of GRBs in that they are of much shorter duration and have relatively soft spectra5. The recurrent sources can thus be considered as a distinct class of objects - the soft gamma repeaters (SGRs). The embryonic distribution of the SGRs suggests that they are of galactic origin4, whereas the distribution6 of GRBs seems to be inconsistent with any known galactic source population. Here we report the detection by the Burst and Transient Source Experiment (BATSE) 7 of three short, very soft transient events from a location consistent with that of the 'old' repeater SGR 1900 + 14 (ref. 8). Our results suggest that the SGR active phase lasts at least 13 years, which, in conjunction with the arguments for a galactic origin, lends support to suggestions4,5 that SGRs are neutron stars. © 1993 Nature Publishing Group.

Published
1993

20. Spatial distribution of γ-ray bursts observed by BATSE

Author

Meegan, C.A. Fishman, G.J. Wilson, R.B. Paciesas, W.S. Pendleton, G.N. Horack, J.M. Brock, M.N. Kouveliotou, C.

Subjects
Astrophysics::High Energy Astrophysical Phenomena
Abstract

THE nature of the sources of cosmic γ-ray bursts is a long-standing problem in astrophysics. Lack of knowledge of their true spatial distribution and of their intrinsic brightness has hampered theoretical understanding of these enigmatic events. The Burst and Transient Source Experiment on the Compton Gamma-Ray Observatory has been detecting bursts at the rate of about one a day, and we report here an analysis of 153 events. The number versus intensity distribution does not follow the -3/2 power law expected for a spatially extended homogeneous distribution of sources, but at the same time the angular distribution is isotropic within statistical limits. Taken together, these results are inconsistent with the spatial distribution of any known population of galactic objects, but may be consistent with the bursts being at cosmological distances. © 1992 Nature Publishing Group.

Published
1992

22. RXTE observations of Cygnus X-3

Author

McCollough, M.L, primary, Robinson, C.R, additional, Zhang, S.N, additional, Harmon, B.A, additional, Paciesas, W.S, additional, Dieters, S.W, additional, Hjellming, R.M, additional, Rupen, M, additional, Mioduszewski, A.J, additional, Waltman, E.B, additional, Ghigo, F.D, additional, Pooley, G.G, additional, Fender, R.P, additional, Cui, W, additional, and Trushkin, S, additional

Published
1998
Full Text
View/download PDF

27. Simultaneous Optical/Gamma-ray Observations of GRBs

Author

Greiner, J., primary, Wensel, W., additional, Hudec, R., additional, Varady, M., additional, Štěpán, P., additional, Spruný, P., additional, Florián, J., additional, Moskalenko, E.I., additional, Barabanov, A.V., additional, Ziener, R., additional, Birkle, K., additional, Bade, N., additional, Tritton, S.B., additional, Ichikawa, T., additional, Fishman, G.J., additional, Kouveliotou, C., additional, Meegan, C.A., additional, Paciesas, W.S., additional, and Wilson, R.B., additional

Published
1995
Full Text
View/download PDF

30. Orbital, precessional and flaring variability of Cygnus X-1.

Author

Brocksopp, C., Fender, R.P., Larionov, V., Lyuty, V.M., Tarasov, A.E., Pooley, G.G., Paciesas, W.S., and Roche, P.

Subjects
METAPHYSICAL cosmology, QUASARS
Abstract

We present the results of a 2.5-yr multiwavelength monitoring programme of Cygnus X-1, making use of hard and soft X-ray data, optical spectroscopy, UBVJHK photometry and radio data. In particular, we confirm that the 5.6-d orbital period is apparent in all wavebands, and note the existence of a wavelength dependence to the modulation, in the sense that higher energies reach minimum first. We also find a strong modulation at a period of 142±7 d, which we suggest is caused by precession and/or radiative warping of the accretion disc. Strong modulation of the hard and soft X-ray flux at this long period may not be compatible with simple models of an optically thin accretion flow and corona in the low state. We present the basic components required for more detailed future modelling of the system – including a partially optically thick jet, quasi-continuous in the low state, the base of which acts as the Comptonizing corona. In addition, we find that there are a number of flares that appear to be correlated in at least two wavebands and generally in more. We choose two of these flares to study in further detail, and find that the hard and soft X-rays are well correlated in the first, and that the soft X-rays and radio are correlated in the second. In general, the optical and infrared show similar behaviour to each other, but are not correlated with the X-rays or radio. [ABSTRACT FROM AUTHOR]

Published
1999
Full Text
View/download PDF

33. CASTER - a scintillator-based black hole finder probe

Author

Paciesas, W.S., primary, Case, G., additional, Cherry, M.L., additional, Cravens, J., additional, Guzik, T.G., additional, Hurley, K., additional, Kippen, R.M., additional, Ryan, J.M., additional, Macri, J.M., additional, McConnell, M.L., additional, Miller, R.S., additional, Schaefer, B.E., additional, Stacy, J.G., additional, Wefel, J.P., additional, and Vestrand, W.T., additional

Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results