Preliminary results from a new analysis method for EGRET data

Thompson, D. J.; Bertsch, D. L.; Hunter, S. D.; Deines-Jones, P.; Dingus, B. L.; Kniffen, D. A.; Sreekumar, P.
April 2000
AIP Conference Proceedings;2000, Vol. 510 Issue 1, p606
Academic Journal
In order to extend the life of EGRET, the gas in the spark chamber was allowed to deteriorate more than was originally planned for the nominal two year Compton Observatory mission. Gamma ray events are lost because the pattern recognition analysis rules are not optimized for the poorer quality data. By changing the rules used by the data analysts, we can recover a significant fraction of the lost events, allowing improved statistics for detection and study of sources. Preliminary results from the Crab, Geminga, and BL Lacertae indicate the feasibility of this analysis. © 2000 American Institute of Physics.


Related Articles

  • EGRET unidentified sources. Grenier, Isabelle A. // AIP Conference Proceedings;2000, Vol. 515 Issue 1, p261 

    Nearly 60% of the EGRET sources are still defeating our attempts at identifying them. The present strategy to elucidate their nature is three-fold: search for counterparts at other wavelengths; search for temporal signatures characteristic of pulsars, binaries or flaring sources; correlation...

  • Could the unidentified EGRET sources in the Gould Belt be of pulsar origin? Zhang, Bing; Harding, Alice K. // AIP Conference Proceedings;2001, Vol. 558 Issue 1, p767 

    We explore the possibility, within the polar cap model, that at least some of the recently identified new population of EGRET sources in the Gould Belt sources are γ-ray pulsars, viewed at large angles to the magnetic axis, such that the line-of-sight misses both the bright gamma-ray double...

  • Gamma-rays from unshocked pulsar winds. Bogovalov, S.; Aharonian, F. // AIP Conference Proceedings;2001, Vol. 558 Issue 1, p127 

    Recently we have shown that the unshocked winds of pulsars could be directly observed through its inverse Compton (IC) γ-ray emission caused by illumination of the wind by low-frequency photons emitted by the surface of the neutron star or by the pulsar's magnetosphere. Limitations imposed by...

  • Ultrahigh-Energy Gamma-Ray Emission from the Geminga Pulsar. Neshpor, Yu. I.; Stepanyan, A. A.; Zyskin, Yu. L.; Kalekin, O. R.; Fomin, V. P.; Chalenko, N. N.; Shitov, V. G. // Astronomy Letters;Apr2001, Vol. 27 Issue 4, p228 

    In 1996-1997, the Geminga pulsar was observed at the Crimean Astrophysical Observatory with a ground-based gamma-ray telescope. An analysis of the observational data suggests that this object is a source of ultrahigh-energy gamma rays. An analysis of the temporal distribution of gamma-ray...

  • Artifact sources near bright EGRET pulsars. Thompson, D. J.; Bertsch, D. L.; Hartman, R. C. // AIP Conference Proceedings;2001, Vol. 587 Issue 1, p668 

    As noted in the Third EGRET Catalog, six sources near the bright Vela pulsar are thought to be artifacts: 3EG J0824-4610, 3EG J0827-4247, 3EG J0828-4954, 3EG J0841- 4356, 3EG J0848-4429, and 3EG J0859-4257. This conclusion is based on analysis of phase-resolved maps of the pulsar region. The...

  • Multiwavelength studies of the peculiar gamma-ray source 3EG J1835+5918. Reimer, O.; Brazier, K. T. S.; Carramin˜ana, A.; Kanbach, G.; Nolan, P. L.; Thompson, D. J. // AIP Conference Proceedings;2000, Vol. 510 Issue 1, p489 

    The source 3EG J1835+5918 was discovered early in the CGRO mission by EGRET as a bright unidentified γ-ray source outside the galactic plane. Especially remarkable, it has not been possible to identify this object with any known counterpart in any other wavelengths band since then. Analyzing...

  • Gamma ray pulsar luminosities. McLaughlin, Maura A.; Cordes, James M. // AIP Conference Proceedings;2000, Vol. 510 Issue 1, p267 

    We apply a likelihood analysis to pulsar detections, pulsar upper limits, and diffuse background measurements from OSSE and EGRET to constrain the γ-ray pulsar luminosity law. We find a steeper dependence on period and magnetic field at OSSE than at EGRET energies. We also find that pulsars...

  • Observation of the millisecond pulsar PSR J0218+4232 by EGRET. Hermsen, W.; Kuiper, L.; Verbunt, F.; Lyne, A.; Stairs, I.; Thompson, D. J.; Cusumano, G. // AIP Conference Proceedings;2000, Vol. 510 Issue 1, p257 

    We report on the likely detection of pulsed high-energy γ-rays from the binary millisecond pulsar PSR J0218+4232 in 100–1000 MeV data from CGRO EGRET. Imaging analysis demonstrates that the highly significant γ-ray source 2EG J0220+4228 (∼10σ) is for energies >100 MeV...

  • The Magnetar Connection. Schilling, Govert // Sky & Telescope;Jan2003, Vol. 105 Issue 1, p19 

    Reports on the similarity of the anomalous X-ray pulsars and soft gamma repeaters as extremely magnetized neutron stars. Production of brief bursts of energetic x-rays; Production of less-energetic radiation; Nature of the bursts results from powerful quakes.


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics