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Title: | Detection of a very low hard X-ray pulse fraction in the bright state of GX 1+4 |
Authors: | Rao, A.R. Paul, Biswajit Chitnis, V.R. Agrawal, P.C. Manchanda, R.K. |
Issue Date: | Sep-1994 |
Publisher: | EDP Sciences |
Citation: | Astronomy and Astrophysics, 1994, Vol.289, pL43-L46 |
Abstract: | We have observed the Galactic center hard X-ray pulsar GX 1+4 on 1993 December 11, in the energy range of 20 - 100 keV with a balloon-borne Xenon filled Multi-cell Proportional Counter (XMPC) telescope. The source was detected in a bright state, the average observed source count rate being 10.1 +/- 0.2/s per detector. X-ray pulsations with a period of 121.0 +/- 0.4 s were detected in the source at a very high significance level. This, compared with the Burst and Transient Source Experiment (BATSE) observations, gives a spin down rate of dot-P = 1.6 +/- 1.4 s/yr. The pulse fraction in the hard X-ray range is low (35%), and the observed spectrum is very hard (power law energy index 0.54 +/- 0.18). The observed source luminosity in the 20 - 100 keV range is 7.9 +/- 0.3 x 1037 erg/s. These properties are similar to those seen during high luminosity spin up state of early 1970s and suggest that the source should revert back to a a spin-up episode. |
Description: | Open Access |
URI: | http://hdl.handle.net/2289/4902 |
ISSN: | 0004-6361 |
Alternative Location: | http://adsabs.harvard.edu/abs/1994A%26A...289L..43R |
Copyright: | 1994 EDP Sciences |
Appears in Collections: | Research Papers (A&A) |
Files in This Item:
File | Description | Size | Format | |
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1994_A&A_V289_p43.pdf Restricted Access | Open Access | 171.71 kB | Adobe PDF | View/Open Request a copy |
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