MAXI J1834-021 (ATel 15932)

ATEL #15932 ATEL #15932

Title: MAXI J1834-021: Swift/XRT detection and localization Author: J. A. Kennea (PSU), K. L. Page (Leicester) and H. Negoro (Nihon U) Queries: jak51@psu.edu Posted: 6 Mar 2023; 21:54 UT Subjects:X-ray, Transient

MAXI reported a new X-ray transient, MAXI J1834-021 (ATEL #15929), first seen around February 5th, 2023. On March 6th, 2023 Swift performed a target of opportunity observation, consisting of 7 pointings of 300s each with XRT in Photon Counting mode, in order to cover the MAXI error region. We find a single bright, uncatalogued point source inside the MAXI error region at the following coordinates: RA/Dec(J2000) = 279.0362, -2.2872, which is equivalent to:

RA(J2000) =18h 36m 08.70s,

Dec(J2000) = -02d 17m 13.9s,

with an error radius 3.5 arc-seconds (90% confidence). This position does not much the position of any known X-ray transient, therefore we consider this the likely counterpart of MAXI J1834-021, and confirm that this is a new transient. The position is coincident with two stars in the Gaia EDR3 catalog, Gaia EDR3 4259671048608866560 and Gaia EDR3 4259671052930848384, with magnitudes G=15.84 and G=20.79 respectively. It$B!G(Bs not possible to rule out either counterpart based on the XRT position.

The source is bright, with a pile-up corrected count rate of 4.4 +/- 0.6 count/s. The spectrum is well described by an absorbed power-law model, with N_H = 1.46 x 10^22 cm^-2, photon index = 2.2 +/- 1.0 and an observed flux of 2.2 +/- 0.9 x 10^-10 erg/s/cm^2 (0.3-10 keV).

We encourage follow-up to identify this new transient.