arXiv subjects

A. A. Lutovinov

Publications and source records attributed to A. A. Lutovinov.

76 records · Page 5Linked to original sources

arXiv2001

The X-ray Source SLX 1732-304 in the Globular Cluster Terzan 1: The Spectral States and an X-ray Burst

The results of ART-P/Granat observations of the X-ray burster SLX1732-304 in the globular cluster Terzan 1 are presented. The X-ray (3-20 keV) fluxes from the source differed by more than a factor of 4 during the observing sessions on September 8 ($F_{\rm X}\simeq6.95\times10^{-10}$ erg cm$^{-2}$ s$^{-1}$) and October 6, 1990 ($F_{\rm X}\simeq1.64\times10^{-10}$ erg cm$^{-2}$ s$^{-1}$). The intensity variations of SLX1732-304 were apparently accompanied by variations in its hardness: whereas the source in its high state had the spectrum with a distinct exponential cutoff typical of bright low-mass X-ray binaries, its low-state spectrum could be satisfactorily described by a simple power law with a photon index $α\simeq1.7$. During the ART-P observation on September 8, a type I X-ray burst was detected from SLX1732-304.

astro-ph↗

arXiv2001

Low State of the X-ray Burster SLX 1732-304 in the Globular Cluster Terzan 1 According to RXTE Data

Observations of the X-ray burster SLX 1732-304 in the globular cluster Terzan 1 with the PCA/RXTE instrument in April 1997 are presented. The source was in a low state; its flux in the standard X-ray band was half the flux recorded by the ART-P/Granat telescope also during its low state. At the same time, its spectrum was softer than the ART-P spectrum; it was well described by a power law with a photon index of 2.3 without any evidence of a high-energy cutoff.

astro-ph↗

arXiv2000

X-Ray Bursters A1742-294 and SLX1744-299/300 Near the Galactic Center

We present a study of two X-ray bursters in the Galactic Center field with the ART-P telescope onboard GRANAT. During 1990-1992 approximately 100 X-ray bursts were detected from the Galactic Center field and most of them were identified with the two persistent sources, A1742-294 and SLX1744-299/300. The burst recurrence times were found to be ~2.4 and ~4.6 hours, respectively, which is significantly shorter them was previously thought. We calculated the mean and maximum fluxes during the bursts and investigated their time profiles. We found that the shape of A1742-294 bursts correlates with the burst peak flux. The spectral analysis was carried out for the strongest burst, detected from A1742-294 on Oct 18, 1990.

astro-ph↗

arXiv2000

An X-ray burst with strong photospheric radius expansion observed from the source 4U1724-307 in Terzan 2

We present results of the RXTE observations of an extremely intense X-ray burst detected from the source 4U1724-307 in the globular cluster Terzan 2. The burst profile was complex consisting of two precursors and a long primary peak. During the first (strong) precursor the source luminosity, L ~ 3.6 x 10^38 erg/s, was comparable with that measured in the main event. The structure of the profile, its dependence on energy and observed spectral evolution indicated strong photospheric expansion of a neutron star. The effective temperature and radius of the photosphere were estimated from the black body model at different stages of expansion, their correlations and specific features of the profile were analyzed and discussed.

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