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| DC Field | Value | Language |
|---|---|---|
| dc.contributor.author | Mukerjee, K. | - |
| dc.contributor.author | Agrawal, P.C. | - |
| dc.contributor.author | Paul, Biswajit | - |
| dc.contributor.author | Rao, A.R. | - |
| dc.contributor.author | Yadav, J.S. | - |
| dc.contributor.author | Seetha, S. | - |
| dc.contributor.author | Kasturirangan, K. | - |
| dc.date.accessioned | 2012-07-17T04:17:53Z | - |
| dc.date.available | 2012-07-17T04:17:53Z | - |
| dc.date.issued | 2001-02 | - |
| dc.identifier.citation | Astrophysical Journal, 2001, Vol. 548, p368-376 | en |
| dc.identifier.issn | 0004-6256 | - |
| dc.identifier.issn | 1538-3881(Online) | - |
| dc.identifier.uri | http://hdl.handle.net/2289/4951 | - |
| dc.description | Restricted Access | en |
| dc.description.abstract | The X-ray pulsar 4U 1907+09 was observed in the 2-18 keV energy band with the Indian X-Ray Astronomy Experiment (IXAE) during 1996 August and again in 1998 June. From the timing measurements, the spin-down rate of the neutron star is measured to be +0.23+/-0.01 s yr-1. A straight-line fit to the historical pulse period data indicates that the pulsar has been in a monotonic phase of spin-down since its discovery. The day-to-day pulse profile indicates some variations during its 8.4 day binary period. The average profile obtained from these observations shows a double-pulse shape with a pronounced asymmetric primary separated by a dip from a relatively weaker but broad secondary. These profiles show a closer resemblance to the pulse shape obtained with the recent observations with the Rossi X-Ray Timing Explorer (RXTE) during 1996 February, as compared to the earlier observations carried out six to 13 years earlier. A secondary flare of 88 mcrab intensity was detected during the IXAE observations in 1996 August. A detailed analysis of the flare data shows the presence of transient 14.4 s oscillations, which may be quasi-periodic during the flaring activity but have a period different from the earlier reported oscillations of 18.2 s as detected by RXTE during the flare of 1996 February. These results, therefore, strengthen the evidence for the presence of a transient accretion disk around the neutron star during the flare, which may be responsible for the continuous slowing down of the pulsar. The studies of such transient quasi-periodic oscillations during flaring activities of 4U 1907+09 thus provide opportunities for understanding the transient behavior of the accretion disk and its physical characteristics. | en |
| dc.language.iso | en | en |
| dc.publisher | IOP Publishing Ltd. | en |
| dc.relation.uri | http://adsabs.harvard.edu/abs/2001ApJ...548..368M | en |
| dc.relation.uri | http://dx.doi.org/10.1086/318655 | en |
| dc.rights | 2001 The American Astronomical Society | en |
| dc.title | Pulse characteristics of the X-Ray pulsar 4U 1907+09 | en |
| dc.type | Article | en |
| Appears in Collections: | Research Papers (A&A) | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 2001_APJ_V548_p368.pdf Restricted Access | Restricted Access | 181.47 kB | Adobe PDF | View/Open Request a copy |
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