Recent timing studies on RXTE observations of 4U 1538-52

Download
2006-07-01
Baykal, Altan
Beklen, E.
The high mass X-ray binary pulsar 4U 1538-52 was observed between July 31 and August 7, 2003. Using these observations, we determined new orbital epochs for both circular and elliptical orbit models. The orbital epochs for both orbit solutions agreed with each other and yielded an orbital period derivative. P/P = (0.4 +/- 1.8) x 10(-6) yr(-1). This value is consistent with the earlier measurement P/P = (2.9 +/- 2.1) x 10(-6) yr(-1) at the 1 sigma level and gives only an upper limit to the orbital period decay. Our determination of the pulse frequency showed that the source spun up at an average rate of 2.76 x 10(-1)4 Hz s(-1) between 1991 and 2003.
ASTRONOMY & ASTROPHYSICS

Suggestions

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...
Upper limits to the SN1006 multi-TeV gamma-ray flux from HESS observations
Aharonian, F; et. al. (EDP Sciences, 2005-07-01)
Observations of the shell-type supernova remnant SN1006 have been carried out with the HESS system of Cherenkov telescopes during 2003 (18.2 h with two operating telescopes) and 2004 (6.3 h with all four telescopes). No evidence for TeV gamma-ray emission from any compact or extended region associated with the remnant is seen and resulting upper limits at the 99.9% confidence level are up to a factor 10 lower than previously-published fluxes from CANGAROO. For SN1006 at its current epoch of evolution we def...
Frequency-resolved spectroscopy of XB1323-619 using XMM-Newton data: detection of a reflection region in the disc
Balman, Şölen (Oxford University Press (OUP), 2010-09-21)
We present the frequency-resolved energy spectra (FRS) of the low-mass X-ray binary dipper XB1323-619 during persistent emission in four different frequency bands using an archival XMM-Newton observation. FRS method helps to probe the inner zones of an accretion disc. XB1323-619 is an Atoll source and a type-I burster. We find that the FRS is well described by a single blackbody component with kT in a range 1.0-1.4 keV responsible for the source variability in the frequency ranges of 0.002-0.04 and 0.07-0.3...
Optical observations of the Be/X-ray transient system KS 1947+300
Kiziloglu, U.; Baykal, Altan; Kiziloglu, N. (Wiley, 2007-01-01)
ROTSE-IIId observations of the Be/X-ray transient system KS 1947+300 obtained between September 2004 and December 2005 make it possible to study the correlation between optical and X-ray activity. The optical outburst of 0.1 mag was accompanied by an increase of the X-ray flux in the 2004 observations. A strong correlation between the optical and X-ray light curves suggests that the neutron star directly accretes from the outflowing material of the Be star. The nearly zero time lag between X-ray and optical...
Very high energy gamma rays from the composite SNR G0.9+0.1
Aharonian, F; et. al. (EDP Sciences, 2005-03-01)
Very high energy (> 100 GeV) gamma-ray emission has been detected for the first time from the composite supernova remnant G0.9+ 0.1 using the HESS instrument. The source is detected with a significance of approximate to 13sigma, and a photon flux above 200 GeV of ( 5.7 +/- 0.7(stat) +/- 1.2(sys)) x 10(-12) cm(-2) s(-1), making it one of the weakest sources ever detected at TeV energies. The photon spectrum is compatible with a power law ( dN/dE proportional to E-Gamma) with photon index Gamma = 2.40 +/- 0.1...
Citation Formats
A. Baykal and E. Beklen, “Recent timing studies on RXTE observations of 4U 1538-52,” ASTRONOMY & ASTROPHYSICS, pp. 1037–1040, 2006, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/38939.