Recent Spin Rate Measurements of 4U 1907+09

Sahiner, S.
Baykal, Altan
In this study, X-ray spectral and pulse timing analysis of the high mass X-ray binary (HMXB) pulsar 4U 1907+09, based on the observations with RXTE are presented. Spin rate measurements indicate a new spin-down episode with a rate close to the previous steady spin-down rate. Orbital phase resolved spectroscopy reveals that the Hydrogen column density varies through the orbit reaching to its maximum value just after periastron. A slight spectral softening with increasing luminosity is aslo observed.


The Spectral and temporal properties of MAXI J1409-619
Dönmez, Çağatay Kerem; Baykal, Altan; Department of Physics (2019)
In this thesis, spectral and timing analysis of the transient high-mass X-ray binary (HMXB) pulsar MAXI J1409-619 are presented. MAXI J1409-619 was discovered in October 2010, and went into an outburst in early December 2010 until February 2011. Observations of Swift and RXTE throughout this period are used in the thesis. The analysis results are in line with the assertion that MAXI J1409-619 is an accretion-powered pulsar. Time-resolved energy spectra of RXTE and Swift data confirm the previously reported ...
Timing and spectral analysis of 2S 1417-624 during its 2018 outburst
Serim, Muhammed Miraç; Ozudogru, O. C.; Donmez, C. K.; Sahiner, S.; Serim, D.; Baykal, Altan; Inam, S. C. (2022-02-01)
We investigate timing and spectral characteristics of the transient X-ray pulsar 2S 1417-624 during its 2018 outburst with NICER follow up observations. We describe the spectra with high-energy cut-off and partial covering fraction absorption (PCFA) model and present flux-dependent spectral changes of the source during the 2018 outburst. Utilizing the correlation-mode switching of the spectral model parameters, we confirm the previously reported sub-critical to critical regime transitions and we argue that ...
Pulse frequency changes of 1E 2259+586 and the binary interpretation
Baykal, Altan (1996-03-20)
Pulse frequencies from the archival ROSAT observations of 1E 2259+586 are presented. A short-term spin-up episode superposed on the secular spin-down trend is observed. Combining the previously published pulse frequencies, we estimate the variance of the angular velocity over a 15 yr span of observations. The level of fluctuations in angular velocity is similar to that of established accreting binary neutron stars. These results favor accretion by a neutron star from a very low mass companion as the source ...
X-ray and optical observations of high mass x-ray binaries
Beklen, Elif; Baykal, Altan; İnam, Çağdaş; Department of Physics (2010)
In this thesis, X-ray and optical observations of accretion powered pulsars are presented. By using archival RXTE observations we work on the X-ray spectral and pulse timing analysis of 4U 1538-52, 4U 1907+09, SMC X-1 to have more detailed information about their orbital and spin parameters. For 4U 1538-52 and SMC X-1, we determined new orbital epochs. By using long term pulse history of 4U 1907+09, we were able to work spin-down trend of the system and also calculate the change in the spin-down rate. Using...
X-ray timing properties of four anomalous x-ray pulsars: 4u 0142+61, 1e 2259+586, 1rxs j170849.0_400910, and 1e 1841_045
Çerri, Danjela; Baykal, Altan; İnam, Sıtkı Çağdaş; Department of Physics (2015)
In this thesis, the detailed X-ray timing characteristics of four Anomalous X-Ray Pulsars (AXPs); 4U 0142+61, 1E 2259+586, 1RXS J170849.0 -400910, and 1E 1841- 045 are presented for glitch free time intervals using data taken by Rossi X-Ray Timing Explorer (RXTE). The pulse arrival times of these AXPs are evaluated by phase coherent timing method. After the removal of the spin-down trend from pulse arrivals, remaining residuals are used for estimation of their noise strengths. Possible correlation of the no...
Citation Formats
S. Sahiner, S. Ç. İNAM, and A. Baykal, “Recent Spin Rate Measurements of 4U 1907+09,” 2010, vol. 1379, Accessed: 00, 2020. [Online]. Available: