The likely progenitor of Nova ASASSN-17hx (=ASASSN-17ib) detected by the VVVX Survey
ATel #10552; R. K. Saito (Universidade Federal de Santa Catarina), M. Hempel (Pontificia Universidad Catolica de Chile, Millennium Institute of Astrophysics), D. Minniti (Universidad Andres Bello, Millennium Institute of Astrophysics, Vatican Observatory)
on 2 Jul 2017; 04:05 UT
Credential Certification: Roberto Saito (email@example.com)
Subjects: Infra-Red, Cataclysmic Variable, Nova
Stanek et al. (ATel #10523) recently reported on the rise of a likely Galactic Nova in the Milky Way disk, confirmed by spectroscopic observations (ATel #10527, #10542). Nova ASASSN-17hx is located at coordinates RA, DEC (J2000) = 18:31:45.918, -14:18:55.57, corresponding to l,b = 17.969, -2.232, within the area covered by the ESO VISTA Variables in the Via Lactea eXtended Survey (VVVX).
VVVX Ks-band observations taken during July and August 2016 show the presence of a faint source 0.84 arcsec apart from the reported target position. The likely progenitor of Nova ASASSN-17hx shows no significant variation in brightness with mean_Ks=16.71+/-0.11, which is within the VVVX photometric errors at these magnitudes. This is the only source down to the limiting magnitude of Ks=17.6 in the field and coincides within 0.65 arcs with the position of the G=19.10 mag Gaia source cited in Kurtenkov, Tomov and Pessev (ATel #10542). Also the coadded VVVX images show a source at these coordinates. Other nearby sources found in the VVVX data are 3 arcs apart from the reported target position.
According to Schlafly et al. (2011, ApJ 737, 103S) the mean extinction for the region around the source position is A_V=4.92 mag, corresponding to A_K=0.58 mag, assuming the Cardelli et al. (1989, ApJ, 345, 245)
The VVVX coordinates and Ks-band light-curve for the likely progenitor of Nova ASASSN-17hx are listed below. We note that the photometric flags indicate a stellar source in only two of the observed epochs, probably due to the contamination by an undetected blended source.
VVVX ID: VVVX J183145.86-141855.4
RA, DEC (J2000) = 18:31:45.86, -14:18:55.4
L,B = 17.97261, -2.22426
VVVX Ks-band variability data
MJD Ks-mag flag
57578.11448876 16.833+/-0.170 +1
57590.08239123 16.679+/-0.146 +1
57591.29292707 16.742+/-0.173 +1
57592.22676851 16.581+/-0.136 +1
57596.09545291 16.621+/-0.141 +1
57597.10955365 no detection
57607.05180765 16.706+/-0.155 +1
57607.14174894 16.953+/-0.193 -1
57609.03246557 16.702+/-0.141 +1
57609.05673931 16.667+/-0.133 +1
57624.06533986 16.621+/-0.136 -1
57625.12911430 no detection
The VVVX data are in the natural VISTA Vegamag system. Photometric flags are similar to those found in the VVV data as described in Saito et al. 2012 (A&A, 537, A107): -1 corresponds to a stellar object, whereas +1 to a non-stellar source.
We gratefully acknowledge use of data from the ESO Public Survey programme ID 198.B-2004 taken with the VISTA telescope, and data products from the Cambridge Astronomical Survey Unit. R.K.S. acknowledges support from CNPq/Brazil.