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Your search keyword '"Parkinson, P. Saz"' showing total 4 results
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4 results on '"Parkinson, P. Saz"'

1. X- AND γ-RAY PULSATIONS OF THE NEARBY RADIO-FAINT PSR J1741–2054.

Author

Marelli, M., Belfiore, A., Parkinson, P. Saz, Caraveo, P., Luca, A. De, Sarazin, C., Salvetti, D., Sivakoff, G. R., and Camilo, F.

Subjects
*NEBULAE, *X-ray astronomy, *PULSATION (Electronics), *STELLAR oscillations, *NEUTRON stars
Abstract

We report the results of a deep XMM-Newton observation of the radio-faint γ-ray pulsar J1741–2054 and its nebula together with the analysis of five years of Fermi Large Area Telescope (LAT) data. The X-ray spectrum of the pulsar is consistent with an absorbed power law plus a blackbody, originating at least partly from the neutron star cooling. The nebular emission is consistent with that of a synchrotron pulsar wind nebula, with hints of spatial spectral variation. We extended the available Fermi LAT ephemeris and folded the γ-ray and X-ray data. We detected X-ray pulsations from the neutron star: both the thermal and non-thermal components are ∼35%-40% pulsed, with phase-aligned maxima. A sinusoid fits the thermal-folded profile well. A 10 bin phase-resolved analysis of the X-ray emission shows softening of the non-thermal spectrum during the on-pulse phases. The radio, X-ray, and γ-ray light curves are single-peaked, not phase-aligned, with the X-ray peak trailing the γ-ray peak by more than half a rotation. Spectral considerations suggest that the most probable pulsar distance is in the 0.3-1.0 kpc range, in agreement with the radio dispersion measure. [ABSTRACT FROM AUTHOR]

Published
2014
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2. The Gamma Ray Burst section of the White Paper on the Status and Future of Very High Energy Gamma Ray Astronomy: A Brief Preliminary Report.

Author

Falcone, A. D., Williams, D. A., Baring, M. G., Blandford, R., Connaughton, V., Coppi, P., Dermer, C., Dingus, B., Fryer, C., Gehrels, N., Granot, J., Horan, D., Katz, J. I., Kuehn, K., Mészáros, P., Norris, J., Parkinson, P. Saz, Pe'er, A., Ramirez-Ruiz, E., and Razzaque, S.

Subjects
*GAMMA ray astronomy, *GAMMA rays, *SPACE astronomy, *ASTRONOMY, *GAMMA ray bursts
Abstract

This is a short report on the preliminary findings of the gamma ray burst (GRB) working group for the white paper on the status and future of very high energy (VHE;>50 GeV) gamma-ray astronomy. The white paper discusses the status of past and current attempts to observe GRBs at GeV-TeV energies, including a handful of low-significance, possible detections. The white paper concentrates on the potential of future ground-based gamma-ray experiments to observe the highest energy emission ever recorded for GRBs, particularly for those that are nearby and have high Lorentz factors in the GRB jet. It is clear that the detection of VHE emission would have strong implications for GRB models, as well as cosmic ray origin. In particular, the extended emission phase (including both afterglow emission and possible flaring) of nearby long GRBs could provide the best possibility for detection. The difficult-to-obtain observations during the prompt phase of nearby long GRBs and short GRBs could also provide particularly strong constraints on the opacity and bulk Lorentz factors surrounding the acceleration site. The synergy with upcoming and existing observatories will, of course, be critical for both identification of GRBs and for multiwavelength/multimessenger studies. [ABSTRACT FROM AUTHOR]

Published
2008
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3. The USA X-ray timing experiment.

Author

Ray, P. S., Wood, K. S., Fritz, G., Hertz, P., Kowalski, M., Johnson, W. N., Lovellette, M. N., Wolff, M. T., Yentis, D., Bandyopadhyay, R. M., Bloom, E. D., Giebels, B., Godfrey, G., Reilly, K., Parkinson, P. Saz, Shabad, G., Michelson, P., Roberts, M., Leahy, D. A., and Cominsky, L.

Subjects
*X-ray binaries, *ASTROPHYSICS
Abstract

The USA Experiment is a new X-ray timing experiment with large collecting area and microsecond time resolution capable of conducting a broad program of studies of galactic X-ray binaries. USA is one of nine experiments aboard the Advanced Research and Global Observation Satellite which was launched February 23, 1999. USA is a collimated proportional counter X-ray telescope with about 1000 cm² of effective area per detector with two detectors sensitive to photons in the energy range 1-15 keV. A unique feature of USA is that photon events are time tagged by reference to an onboard GPS receiver allowing precise absolute time and location determination. We will present an overview of the USA instrument, capabilities, and scientific observing plan as well as the current status of the instrument. [ABSTRACT FROM AUTHOR]

Published
2001

4. Shot noise in USA lightcurves of XTE J1118+480 and cygnus X-1.

Author

Focke, Warren B., Bloom, E. D., Giebels, B., Godfrey, G., Reilly, K. T., Parkinson, P. Saz, Shabad, G., Wood, K. S., Ray, P. S., Bandyopadhyay, R. M., Wolff, M. T., Fritz, G., Hertz, P., Kowalski, M. P., Lovellette, M. N., Yentis, D., and Scargle, Jeffrey D.

Subjects
*CYGNUS X-1, *LIGHT curves, *BINARY stars
Abstract

We investigate the behavior of the new transient black hole candidate XTE J1118+480 using shot noise models in the time domain. Using light curves from the Unconventional Stellar Aspect experiment (USA), we model a portion of the emission as a superposition of shots. Individual structures in the light curve are fit to a template function. The results are compared to a similar analysis performed on light curves from Cygnus X-1. Results indicate that the characteristic timescale for XTE J1118+480 is around 3 times as long as for Cygnus X-1. [ABSTRACT FROM AUTHOR]

Published
2001

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