Loading...
Please wait, while we are loading the content...
Similar Documents
A Frequency Glitch in an Accreting Pulsar
| Content Provider | Semantic Scholar |
|---|---|
| Author | Galloway, Duncan K. Morgan, Edward H. Levine, Alan M. |
| Copyright Year | 2004 |
| Abstract | Frequency glitches have been observed so far only in radio pulsars and anomalous X-ray pulsars. Here we present evidence of a glitch in a neutron star accreting from a Be companion. The transient KS 1947+300 reappeared in 2000 October as a moderately strong X-ray source that exhibited 18.7 s pulsations, leading to an identification with the BATSE source GRO J1948+32, last detected in 1994. We have analyzed Rossi X-ray Timing Explorer observations taken during the 2000–01 outburst, as well as additional observations taken during a smaller outburst in July 2002. Orbital Doppler shifts are apparent in the temporal variation of the pulse frequency. A joint fit of the RXTE data together with BATSE measurements from an outburst in 1994 yields the orbital period Porb = 40.415±0.010 d, the projected orbital radius ax sin i = 137± 3 lt-s, and the eccentricity e = 0.033± 0.013. This degree of eccentricity is unexpectedly low for such a wide orbit. Pulse timing results also show that the intrinsic pulse frequency increased from 53.30 to 53.47 mHz at a rate approximately proportional to the X-ray flux. This is about the degree of spin up expected from the accretion torques that must be present when the X-ray luminosity reaches ∼ 10 ergs s. On one occasion during the 2000–01 outburst, the pulse frequency increased by ∼ 1.8×10 Hz in . 10 hr over and above the mean trend seen around that time, without any indication of a correspondingly large increase in X-ray flux. The fractional change in frequency of 3.7 × 10 during this event is significantly larger than the values observed in the glitches in radio pulsars and anomalous X-ray pulsars. We discuss other similarities and differences between these events. Subject headings: accretion — pulsars: general — pulsars: individual (KS 1947+300) — X-rays: stars |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/astro-ph/0401476v1.pdf |
| Alternate Webpage(s) | http://arxiv.org/pdf/astro-ph/0401476v2.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Amoxicillin Diagnostic radiologic examination Distance (graph theory) GUCY2C protein, human Glitch Hertz (Hz) Large Medical Subject Headings Moderate Response Molecular orbital Neutrons Orbital magnetization PULSAR: Lost Colony Projections and Predictions Rajiformes Small Stars, Celestial |
| Content Type | Text |
| Resource Type | Article |
