X-ray flux related timing and spectral features of 2S 1417-62

Download
2004-03-21
Inam, SC
Baykal, Altan
Scott, DM
Finger, M
Swank, J
Rossi X-ray Timing Explorer (RXTE) observations of the X-ray transient pulsar 2S 1417-62 between 1999 November and 2000 August with a total exposure of similar to394 ks have been analysed. Observations include a main outburst followed by a series of mini outbursts. Changes in pulse morphology and pulse fraction were found to be related to the changes in X-ray flux. Particularly low X-ray flux regions were found to have significantly lower pulse fractions with different pulse morphologies. The 3-60 keV Proportional Counter Array (PCA) High-Energy X-ray Timing Experiment (HEXTE) main outburst spectrum was modelled with an absorbed power-law model with high-energy cut-off and a Gaussian iron line complex feature. Using the same spectral model, individual 3-20 keV PCA spectra were found to be softer and less absorbed in low X-ray flux regions between outbursts. Spectral studies showed that hydrogen column density was correlated, and the power-law index was anticorrelated with the 3-20 keV X-ray flux. X-ray flux related spectral and timing features in 2S 1417 62, except for low X-ray flux regions, were interpreted as a sign of disc accretion with a similar accretion geometry with a varying mass accretion rate ((M)over dot), whereas spectral and timing features of the low X-ray flux regions were interpreted as a sign of possible temporary accretion geometry change prior to the next periastron where (M)over dot increases again to restore the original accretion geometry.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

Suggestions

X-ray spectral evolution of Her X-1 in a low state and the following short high state
Inam, SC; Baykal, Altan (Oxford University Press (OUP), 2005-08-21)
We analysed spectral variations of similar to 8.5-d long Rossi X-ray Timing Explorer (RXTE) monitoring observations of Her X-1 in 2001 December. This set of observations enables, for the first time, frequent continuous monitoring (111 pointings in similar to 8.5 d) of the source with RXTE including a similar to 1.7-d-long low state part and the following similar to 6.8-d-long short high state part. We used an absorbed power-law model with an iron line energy complex modelled as a Gaussian to fit both the 3-...
Recent X-ray measurements of the accretion-powered pulsar 4U 1907+09
in't Zand, JJM; Baykal, Altan; Strohmayer, TE (IOP Publishing, 1998-03-20)
X-ray observations of the accreting X-ray pulsar 4U 1907 + 09 obtained during 1996 February with the Proportional Counter Array onboard the Rossi X-Ray Timing Explorer (RXTE) have made possible the first measurement of the intrinsic pulse period (P-pulse) since 1984: P-pulse = 440.341(-0.017)(+0.012) s. 4U pulse 1907 + 09 is in a binary system with a blue supergiant. The orbital parameters have been solved, which enables us to correct a measurement of P-pulse obtained in 1990 with Ginga for orbital delay ef...
Discovery of the orbit of the transient X-ray pulsar SAX J2103.5+4545
Baykal, Altan; Swank, J (IOP Publishing, 2000-12-01)
Using X-ray data from the Rossi X-Ray Timing Explorer (RXTE), we carried out a pulse-timing analysis of the transient X-ray pulsar SAX J2103.5+4545. An outburst was detected by the All-Sky Monitor (ASM) in 1999 October 25 and reached a peak X-ray brightness of 27 mcrab on October 28. Between November 19 and December 27, the RXTE Proportional Counter Array (PCA) carried out pointed observations that provided us with pulse arrival times. These yield an eccentric orbit (e = 0.4 +/- 0.2) with an orbital period ...
X-RAY SPECTRAL AND OPTICAL PROPERTIES OF A ULX IN NGC 4258 (M106)
Avdan, H.; Avdan, S.; AKYÜZ, AYSUN; Balman, Şölen; AKSAKER, NAZIM; AKKAYA ORALHAN, Inci (American Astronomical Society, 2016-09-10)
We study the X-ray and optical properties of the ultraluminous X-ray source (ULX) X-6 in the nearby galaxy NGC 4258 (M106) based on the archival XMM-Newton, Chandra, Swift, and Hubble Space Telescope (HST) observations. The source has a peak luminosity of L-X similar to 2 x 10(39) erg s(-1) in the XMM-Newton observation of 2004 June. Consideration of the hardness ratios and the spectral model parameters shows that the source seems to exhibit possible spectral variations throughout the X-ray observations. In...
X-ray outburst of 4U 0115+634 and ROTSE observations of its optical counterpart V635 Cas
Baykal, Altan; Kiziloglu, N; Balman, S; Inam, SC (EDP Sciences, 2005-09-01)
ROTSE IIId ( The Robotic Optical Transient Experiment) observations of the X-ray binary system 4U 0115+634/V635 Cas obtained during 2004 June and 2005 January make it possible, for the first time, to study the correlation between optical and type II X-ray outbursts. The X-ray outburst sharply enhanced after periastron passage where the optical brightness was reduced by 0.3 mag for a few days. We interpret the sharp reduction of optical brightness as a sign of mass ejection from the outer parts of the disc o...
Citation Formats
S. Inam, A. Baykal, D. Scott, M. Finger, and J. Swank, “X-ray flux related timing and spectral features of 2S 1417-62,” MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, pp. 173–180, 2004, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48369.