MAXI J1828-249: REM optical/NIR observations
ATel #5559; P. D'Avanzo, S. Campana, S. Covino (INAF-OAB), P. Goldoni (APC/Univ. of Paris 7, CEA/Irfu), T. Munoz-Darias (Univ. of Oxford), N. Masetti, E. Palazzi (INAF-IASFBo)
on 8 Nov 2013; 09:00 UT
Credential Certification: Paolo D'Avanzo (paolo.davanzo@brera.inaf.it)
Subjects: Infra-Red, Optical, Binary, Transient
We observed the field of the X-ray transient MAXI J1828-249 (ATels #5474, #5476, #5478) with the 60cm REM robotic telescope located in La Silla (Chile). Observations were carried out simultaneously in the optical and near-infrared (NIR) on 2013 Oct 19 from 00:00:26 UT to 00:36:42 UT (MJD 56584.0003 - 56584.0255).
The optical/NIR counterpart (ATel #5479, #5482) is clearly detected with the following AB magnitudes (not corrected for Galactic reddening):
g = 17.3 +/- 0.1
r = 17.1 +/- 0.1
i = 17.3 +/- 0.1
z = 17.1 +/- 0.1
J = 17.0 +/- 0.1
H = 17.3 +/- 0.1
We could not detect the source in the Ks band down to a magnitude of 17.4 (3-sigma confidence level). The photometric calibration was carried out against Landolt standard stars and the 2MASS catalogue for the optical and NIR bands, respectively.
Once corrected for the Galactic reddening E(B-V)~0.34 mag (Schlafly et al. 2011), the nu vs. f(nu) optical/NIR spectral energy distribution can be satisfactorily fitted by a simple power-law with index = 0.8 +/- 0.2.
Compared with the values reported by Rau et al. (ATel #5482) our photometry shows evidence of a bluer spectrum and moderate fading, further strengthening the identification of this source as the optical/NIR counterpart of MAXI J1828-249.
