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http://hdl.handle.net/2289/3917Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.author | Jain, Chetana | - |
| dc.contributor.author | Paul, Biswajit | - |
| dc.contributor.author | Dutta, Anjan | - |
| dc.date.accessioned | 2010-07-22T04:55:29Z | - |
| dc.date.available | 2010-07-22T04:55:29Z | - |
| dc.date.issued | 2010-04 | - |
| dc.identifier.citation | Monthly Notices of the Royal Astronomical Society, 2010, Vol.403, p920 | en |
| dc.identifier.issn | 1365-2966 -(Online) | - |
| dc.identifier.issn | 0035-8711 | - |
| dc.identifier.uri | http://hdl.handle.net/2289/3917 | - |
| dc.description | Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations) | en |
| dc.description.abstract | 4U 1626− 67 is an accretion powered X-ray pulsar that shows remarkably stable X-ray luminosity above a time-scale of hours and gradual intensity variation on a time-scale of a few years. Unlike the other high magnetic field binary X-ray pulsars, the spin-up or spin-down rate of the neutron star is also very stable on time-scales up to several years. Here, we report a significant increase in the X-ray intensity in the long-term Rossi X-ray Timing Explorer (RXTE) All Sky Monitor light curve of 4U 1626− 67. Similar enhancement in the X-ray flux has also been detected in the Swift Burst Alert Telescope light curve. The increase in the X-ray flux took place over a long period of about 100 d and there appear to be two episodes of flux enhancement. We have investigated the spectral and timing features of 4U 1626− 67 during its current state of enhanced flux emission with data obtained from the Proportional Counter Array and the High-Energy X-ray Timing Explorer on board RXTE. We report the detection of a torque reversal to spin-up in 4U 1626− 67. The source has entered a new spin-up phase with a spin-up rate of 4.02(5) × 10−13 Hz s−1 . The present spin-up rate is almost half of the earlier spin-up and spin-down trends. A significant excess in soft X-ray photon emission is observed during the enhanced flux state, which is similar to the energy spectrum obtained during the spin-up era of the pulsar before 1990. 4U 1626− 67 is a unique accretion powered X-ray pulsar in which quasi-periodic oscillations have been consistently observed over the past ∼20 years. During the recent observations, however, we did not detect a quasi-periodic oscillation at frequencies as seen in earlier observations. Instead, we report detection of a significant broadening in the wings of the 130 mHz peak and a change in the shape of the continuum of the power spectrum. These results indicate that the flux enhancement is not a simple case of increased mass accretion rate, but there is also a change in the accretion geometry in the vicinity of the neutron star. | en |
| dc.language.iso | en | en |
| dc.publisher | Wiley Interscience for the RAS | en |
| dc.relation.uri | http://adsabs.harvard.edu/abs/2010MNRAS.403..920J | en |
| dc.relation.uri | http://arxiv.org/abs/0906.4169 | en |
| dc.relation.uri | http://dx.doi.org/10.1111/j.1365-2966.2009.16170.x | en |
| dc.rights | 2010 The Royal Astronomical Society | en |
| dc.subject | Pulsars | en |
| dc.subject | X-ray binaries | en |
| dc.subject | X-ray pulsar | en |
| dc.subject | X-ray:stars | en |
| dc.title | Spectral and temporal changes associated with flux enhancement in 4U 1626-67 | en |
| dc.type | Article | en |
| Appears in Collections: | Research Papers (A&A) | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 2010_MNRAS_403_920.pdf Restricted Access | Restricted Access | 699.39 kB | Adobe PDF | View/Open Request a copy |
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