Swift/XRT follow-up observation of XTE J1810-189

ATel #14009; E. Bozzo (ISDC, Switzerland), J. Wilms (ECAP, Germany), E. Kuulkers (ESA/ESTEC, Netherlands - on behalf of the Galactic bulge monitoring program team), L. Sidoli (INAF-IASF, Italy), C. Sanchez-Fernandez (ESA/ESAC, Spain), A. Paizis (INAF-IASF, Italy), J. Chenevez (DTU, Denmark), C. Ferrigno, V. Savchenko (ISDC, Switzerland), L. Ducci (ISDC, Switzerland; IAAT, Germany)
on 14 Sep 2020; 14:46 UT
Credential Certification: E. Bozzo (enrico.bozzo@unige.ch)

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Following the report of hard X-ray activity from the direction of XTE J1810-189 by INTEGRAL (ATel #13983), a short follow-up observation was triggered with Swift/XRT in order to determine the position of the source down to the arc-second accuracy.

The Swift/XRT observation was carried out on 2020 September 10 at 00:00 UT for a total effective exposure time of 1 ks. A single X-ray source is found within the XRT field of view. The best determined position of the source is at RA=272.58709, DEC=-19.07013 (J2000), with an associated accuracy of 2.2 arcsec at 90% confidence level (we used the XRT on-line tool; see Evans et al. 2009, MNRAS, 397, 1177).

The source spectrum could be well described by a power-law with a photon index of 1.8+/-0.4 and a 0.5-10 keV flux of (3.9+/-0.5)E-10 erg/cm^2/s (not corrected for absorption). The absorption column density in the direction of the source estimated by Swift/XRT is 6.0 (+1.4, -1.2) E22 cm^-2.

The position determined from XRT is compatible with the previous localization of XTE J1810-189 (ATel #1432), thus confirming that the detected enhanced X-ray activity observed by INTEGRAL is coming from this source.

We thank the Swift team for the rapid planning and execution of our requested follow-up observation.