Localization of EXO 1846-031 by Swift/XRT

ATel #12969; I. A. Mereminskiy(1), R. A. Krivonos(1), P. S. Medvedev(1), S. A. Grebenev(1) (1: IKI RAS, Moscow, Russia)
on 31 Jul 2019; 12:01 UT
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Credential Certification: Ilya Mereminskiy (i.a.mereminskiy@gmail.com)

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Using Swift/XRT observation we obtained localization of EXO 1846-031, ultra-soft X-ray transient which recently went into the outburst (ATel #12968). Enhanced position (Goad et al., 2007) is 282.32081, -3.06538 with 2" error radius (90%), which is remarkable close to the initial position reported by Parmar et al, 1993 - less then 2".
We also extracted XRT spectrum using online tool (Evans et al., 2009). It could be adequately described (chi²_red~1.5) by absorbed powerlaw (tbabs*power) model, with N_H~5x10²² cm^-2, and power-law slope of 0.9(±0.25). Total (absorbed) flux in 0.5-10 keV band is about 5x10^-9 erg/cm²/s.
We found two probable candidates in UKIDSS survey (Lucas et al, 2012): UKIDSS J184917.09-030355.9 at 1.7" offset - relatively bright source, with Kmag = 11.6. SED of the source show strong reddening, consistent with previously reported absorption column thickness of ~10²² cm^-2. We propose this source as a candidate counterpart. There is also source at 2.1" offset, just outside the error circle - UKIDSS J184916.87-030354.3 which is fainter, Kmag = 16.6.
IR and X-ray observations are encouraged in order to identify the optical counterpart.