VVV-WIT-04: a likely transient counterpart of the radio source PMN J1515-5559
ATel #8456; R. K. Saito (UFS, Brazil), M. V. da Silva (UFS, Brazil), I. S. Melo (UFS, Brazil), D. Minniti (UNAB, Chile; Vatican Observatory; MAS, Chile), V. D. Ivanov (ESO, Germany), N. Masetti (INAF/IASF Bologna, Italy), A. F. Rojas (UNAB, Chile)
on 23 Dec 2015; 18:21 UT
Credential Certification: Roberto Saito (saito@ufs.br)
Subjects: Radio, Infra-Red, Nova, Transient
We report the discovery of a transient source by the VVV Survey (vvvsurvey.org; Minniti et al. 2010, New Astronomy, 15, 433) likely related to the radio source PMN J1515-5559 (Wright et al. 1994, ApJS, 91, 111).
Observations of the VVV disk area taken during 2010-2013 show a stellar source which increases in brightness by Delta_Ks>2.5 mag during the 2013 season (https://figshare.com/articles/Curva_de_luz_bmp/2056374). The coordinates of VVV-WIT-04 are (RA,DEC)=15:15:12.69,-55:59:32.78, corresponding to (l,b)=-37.869,1.432. VVV-WIT-04 is about 1.8 arcs apart from the radio source PMN J1515-5559 and it is the only source within 2 arcs from its position down to Ks~18 mag.
There are previous entries in the literature for the VVV-WIT-04 position: LQAC 228-055_001 (0.14 arcs apart from the VVV coordinates; Souchay et al. 2015, A&A, 583, A75) and WISE J151512.70-555932.2 (0.54 arcs apart; Cutri et al. 2012, VizieR Online Data Catalog, 2311). The position of VVV-WIT-04 moves about 0.2 arcs mostly along RA while the object increases in brightness, suggesting contamination by a blended source. When VVV-WIT-04 is in the high-stage it dominates the position while the contamination is stronger when VVV-WIT-04 is faint, moving the centroid towards the position of the contaminator.
The data suggest that VVV-WIT-04 could be a Galactic nova with an undetectable progenitor or even a supernova in a background radio-loud galaxy towards the MW disk. Further observations are encouraged in order to confirm the nature of VVV-WIT-04.
VVV-WIT-004 Table of Observations
Date (UT) filter mag flag
2010-03-30.2973 Y 18.547 0.058 -1
2010-03-30.3018 Z 19.708 0.104 +1
2010-04-01.2924 H 15.883 0.018 -2
2010-04-01.2971 Ks 14.704 0.013 -1
2010-04-01.3018 J 17.314 0.033 -2
2010-06-27.1623 Ks 15.874 0.064 -1
2010-08-14.0077 Ks 15.913 0.064 -1
2010-08-15.0662 Ks 15.916 0.066 -1
2010-08-17.0361 Ks 16.051 0.069 +1
2010-08-22.0372 Ks 16.008 0.081 -1
2011-08-30.0393 Ks 16.110 0.079 -2
2011-09-13.9926 Ks 16.196 0.092 +1
2011-09-14.9870 Ks 16.273 0.099 -1
2011-09-15.9880 Ks 16.181 0.088 -1
2011-09-18.0042 Ks 16.174 0.083 +1
2012-05-08.3022 Ks 15.818 0.057 -1
2012-05-21.2887 Ks 16.009 0.073 -1
2013-02-05.3548 Ks 15.618 0.070 +1
2013-03-14.2609 Ks 15.192 0.039 -1
2013-03-20.3482 Ks 14.830 0.030 -1
2013-03-21.2801 Ks 15.104 0.044 -1
2013-03-22.2215 Ks 15.010 0.033 -1
2013-03-23.2747 Ks 15.302 0.064 -1
2013-03-24.2302 Ks 15.288 0.034 -1
2013-03-26.1707 Ks 14.600 0.022 -1
2013-04-06.4126 Ks 14.224 0.015 -1
2013-05-09.3793 Ks 13.425 0.012 -1
2013-05-10.3114 Ks 13.643 0.015 -1
2013-06-15.1027 Ks 13.958 0.013 -1
2013-06-16.0309 Ks 13.997 0.014 -1
2013-06-17.0773 Ks 14.067 0.012 -1
2013-06-18.1928 Ks 13.965 0.016 -1
2013-06-19.2526 Ks 13.747 0.013 -1
2013-06-26.1893 Ks 14.060 0.017 -1
2013-06-27.1297 Ks 14.062 0.013 -1
2013-06-28.0304 Ks 14.067 0.013 -1
2013-06-29.0730 Ks 14.091 0.013 -1
2013-06-30.0201 Ks 13.858 0.010 -1
The VVV data are in the natural VISTA Vegamag system. Photometric flags are described in Saito et al. 2012 (A&A, 537, A107).
Acknowledgments: We gratefully acknowledge use of data from the ESO Public Survey programme ID 179.B-2002 taken with the VISTA telescope, and data products from the Cambridge Astronomical Survey Unit. R.K.S. acknowledges support from CNPq/Brazil.
VVV Ks-band light-curve of VVV-WIT-04
