Michael R. Pelling

In-Flight Performance of the High Energy X-Ray Timing Experiment on the Rossi X-Ray Timing Explorer

The High Energy X-Ray Timing Experiment (HEXTE) is one of three scientific instruments aboard the Rossi X-Ray Timing Explorer (RXTE), which was launched on 1995 December 30. RXTE performs timing and spectral studies of bright X-ray sources to determine the physical parameters of these systems. The HEXTE consists of two independent clusters of detectors, each cluster containing four NaI(Tl)/CsI(Na) phoswich scintillation counters sharing a common 1° FWHM field of view. The field of view of each cluster is switched on and off source to provide near real-time background measurements. The net open area of the eight detectors is 1600 cm2, and each detector covers the energy range 15-250 keV with an average energy resolution of 15.4% at 60 keV. The in-flight performance of the HEXTE is described, the light curve and spectrum of the Crab Nebula/pulsar is given, and the 15-240 keV spectrum of the weak source, active galaxy MCG +8-11-11 is presented to demonstrate the weak source spectral capabilities of HEXTE.

EVIDENCE OF X-RAY SYNCHROTRON EMISSION FROM ELECTRONS ACCELERATED TO 40 TeV IN THE SUPERNOVA REMNANT CASSIOPEIA A

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 Timing Explorer satellite. In addition to the previously reported strong emission-line features produced by thermal plasmas, the broadband spectrum has a high-energy “tail” that extends to energies at least as high as 120 keV. This tail may be described by a broken power law that has photon indices of G1 5 1.820.6

Discovery of a Third Harmonic Cyclotron Resonance Scattering Feature in the X-Ray Spectrum of 4U 0115+63

We have discovered a third harmonic cyclotron resonance scattering feature (CRSF) in observations of the recent outburst of 4U 0115+63 with the Rossi X-Ray Timing Explorer (RXTE). The spectrum in a narrow pulse phase range shows CRSFs at 12.40, 21.45, and 33.56 keV. With centroid energy ratios to the fundamental of 1.73 ± 0.08 and 2.71 ± 0.13, the CRSFs are not harmonically spaced. Strong variability of the continuum and CRSFs with pulse phase indicate a complex emission geometry near the neutron star polar cap. In addition, one RXTE observation, which spanned periastron passage, revealed a strong 2 mHz quasi-periodic oscillation (QPO). This is slower by 2 orders of magnitude than the beat-frequency QPO expected in this system and slower by a factor of more than 5 compared with other QPOs seen in accreting X-ray pulsars.

The x-ray spectrum of the plerionic system psr b1509-58/msh 15-52

We present the results of observations of the PSR B1509

The 1999 Hercules X-1 Anomalous Low State

-

CdZnTe arrays for astrophysics applications

58/MSH 15

CZT detectors read out with the RENA-2 ASIC

-

CZT detectors with 3D readout for gamma-ray spectroscopy and imaging

52 system in X-rays (

Performance of a prototype CdZnTe detector module for hard x-ray astrophysics

2-250

Design and performance of the HEXIS CZT detector module

keV) by the Rossi X-ray Timing Explorer. The spectra of the peak of the pulsed component (radio phase