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Does the Blazar Gamma-Ray Spectrum Harden with Increasing Flux? Analysis of 9 Years of EGRET Data
Giridhar Nandikotkur, Keith M. Jahoda, R. C. Hartman +5
The Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma-Ray Observatory (CGRO) discovered gamma-ray emission from more than 67 blazars during its 9 yr lifetime. W…
The spectrum of the cosmic X-ray background observed by RTXE/PCA
M. Revnivtsev, M. Gilfanov, R. Sunyaev +2
We have analyzed a large set of RXTE/PCA scanning and slewing observations performed between April 1996 and March 1999. We obtained the 3-20 keV spectrum of the cosmic X-ray backgr…
X-ray spectral variability of the Seyfert galaxy NGC 4051
G. Lamer, I. M. McHardy, P. Uttley +1
We report on the X-ray spectral variability of the Seyfert 1 galaxy NGC 4051 observed with the Rossi X-ray Timing Explorer (RXTE) during a 1000 day period between May 1996 and Marc…
The 2-10 keV XRB dipole and its cosmological implications
C. A. Scharf, K. Jahoda, M. Treyer +3
The hard X-ray (>2 keV) emission of the local and distant Universe as observed with the HEAO1-A2 experiment is reconsidered in the context of large scale cosmic structure. Using al…
X-ray Observations of BL Lacertae During 1997 Outburst and its Association with Quasar-like Characteristics
G. Madejski, M. Sikora, T. Jaffe +3
This paper reports on the X-ray emission from BL Lacertae during its July 1997 outburst as observed with the Rossi X-ray Timing Explorer (RXTE), compares the RXTE data to previous…
Observation of Cen A by the Rossi X-ray Timing Explorer
R. E. Rothschild, D. L. Band, P. R. Blanco +13
The Rossi X-ray Timing Explorer made a short (10 ks) observation of the radio galaxy Centaurus A on 14 August 1996. Analysis of the combined 2.5-240 keV spectrum has revealed a hea…
RXTE Absolute Timing Results for the Pulsars B1821-24 and B1509-58
A. H. Rots, K. Jahoda, D. J. Macomb +9
Observations with the Rossi X-ray Timing Explorer and the Jodrell Bank, Parkes, and Green Bank telescopes have enabled us to determine the time delay between radio and X-ray pulses…
Milli-second Oscillations in the Persistent and Bursting Flux of Aql X-1 During an Outburst
W. Zhang, K. Jahoda, R. L. Kelley +2
The Rossi X-Ray Timing Explorer observed the soft X-Ray transient Aql X-1 during its outburst in February and March 1997. We report the discovery of quasi-periodic oscillations (QP…
The Pulsar in GRO J1744-28 at Low Flux
Michael J. Stark, A. M. Ahearn, L. J. Duva +1
The Bursting Pulsar, GRO J1744-28, has been observed with the Rossi X-ray Timing Explorer (RXTE) regularly since the launch of the satellite in December 1995. This accretion driven…
The X-ray Spectrum of the Plerionic System PSR B1509-58/MSH 15-52
D. Marsden, P. R. Blanco, D. E. Gruber +7
We present the results of observations of the PSR B150958/MSH 1552 system in X-rays ( keV) by the Rossi X-ray Timing Explorer. The spectra of the peak of the pulsed co…
Evidence of X-ray Synchrotron Emission from Electrons Accelerated to 40 TeV in the Supernova Remnant Cassiopeia A
G. E. Allen, J. W. Keohane, E. V. Gotthelf +9
We present the 2-60 keV spectrum of the supernova remnant Cassiopeia A measured using the Proportional Counter Array and the High Energy X-ray Timing Experiment on the Rossi X-ray…
A Broad Band and Large Area X-Ray Omni Sky Monitor (BLOSM)
W. Zhang, R. Petre, A. N. Peele +4
We present a conceptual design for a new X-ray all sky monitor (ASM). Compared with previous ASMs, its salient features are: (1) it has a focusing capability that increases the sig…
Discovery of Sub-Millisecond Quasi-Periodic Oscillations in the X-Ray Flux of Scorpius X-1
M. Van der Klis, J. H. Swank, W. Zhang +5
We report the discovery, with NASA's Rossi X-ray Timing Explorer (RXTE), of the first sub-millisecond oscillation found in a celestial X-ray source. The quasi-periodic oscillations…
ON THE MEASUREMENT OF A COSMOLOGICAL DIPOLE IN THE PHOTON NUMBER COUNTS OF GAMMA-RAY BURSTS
C. A. Scharf, K. Jahoda, E. Boldt
If gamma-ray bursts are cosmological or in a halo distribution their properties are expected to be isotropic (at least to 1st order). However, our motion with respect to the burst…