Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-11-25
Mon.Not.Roy.Astron.Soc. 349 (2004) 94
Astronomy and Astrophysics
Astrophysics
5 pages, 1 figure, accepted for publication by MNRAS
Scientific paper
10.1111/j.1365-2966.2004.07455.x
We present the analysis of a 35 ksec long Chandra observation of the neutron star soft X-ray transient (SXT) SAX J1810.8-2609. We detect three sources in the field of view. The position of one of them is consistent with the location of the ROSAT error circle of SAX J1810.8-2609. The accurate Chandra position of that source coincides with the position of the proposed optical counterpart, strengthening the identification as the counterpart. We detected the neutron star SXT system in quiescence at an unabsorbed luminosity of ~1x10^32 erg s^-1 (assuming a distance of 4.9 kpc). This luminosity is at the low-end of quiescent luminosities found in other neutron star SXTs. This renders support to the existence of a group of faint soft X-ray transients of which the accreting millisecond X-ray pulsar SAX J1808.4-3658 is the most prominent member. The quiescent spectrum of SAX J1810.8-2609 is well-fit with an absorbed power law with photon index of 3.3+-0.5. With a value of 3.3x10^21 cm^-2 the Galactic absorption is consistent with the value derived in outburst. Since the spectra of quiescent neutron star SXTs are often fit with an absorbed blackbody or neutron star atmosphere plus power-law model we also fitted the spectrum using those fit functions. Both models provide a good fit to the data. If cooling of the neutron star core and/or crust is responsible for the soft part of the spectrum the time averaged mass accretion rate must have been very low (~5.7x10^-13 Msun yr^-1; assuming standard core cooling only) or the neutron star must be massive. We also discuss the possibility that the thermal spectral component in neutron stars in quiescence is produced by residual accretion.
Jonker Peter G.
van der Klis Michiel
Wijnands Rudy
No associations
LandOfFree
The faint neutron star soft X-ray transient SAX J1810.8-2609 in quiescence does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The faint neutron star soft X-ray transient SAX J1810.8-2609 in quiescence, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The faint neutron star soft X-ray transient SAX J1810.8-2609 in quiescence will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-670118