Bibcode
Armas Padilla, M.; Degenaar, N.; Patruno, A.; Russell, D. M.; Linares, M.; Maccarone, T. J.; Homan, J.; Wijnands, R.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 417, Issue 1, pp. 659-665.
Advertised on:
10
2011
Citations
33
Refereed citations
31
Description
The X-ray transient XTE J1719-291 was discovered with Rossi X-ray Timing
Explorer/Proportional Counter Array (RXTE/PCA) during its outburst in
2008 March, which lasted at least 46 d. Its 2-10 keV peak luminosity is
7 × 1035 erg s-1 assuming a distance of 8
kpc, which classifies the system as a very faint X-ray transient. The
outburst was monitored with Swift, RXTE, Chandra and XMM-Newton. We
analysed the X-ray spectral evolution during the outburst. We fitted the
overall data with a simple power-law model corrected for absorption and
found that the spectrum softened with decreasing luminosity. However,
the XMM-Newton spectrum cannot be fitted with a simple one-component
model, but it can be fitted with a thermal component (blackbody or disc
blackbody) plus a power-law model affected by absorption. Therefore, the
softening of the X-ray spectrum with decreasing X-ray luminosity might
be due to a change in photon index or alternatively it might be due to a
change in the properties of the soft component. Assuming that the system
is an X-ray binary, we estimated a long-term time-averaged mass
accretion rate of ?˜ 7.7 × 10-13
M&sun; yr-1 for a neutron star as a compact object
and ?˜ 3.7 × 10-13 M&sun;
yr-1 in the case of a black hole. Although no conclusive
evidence is available about the nature of the accretor, based on the
X-ray/optical luminosity ratio we tentatively suggest that a neutron
star is present in this system.