BVRI Photometry on MASTER OT in NGC 2748
ATel #10686; J. Vinko, K. Sarneczky, O. Hanyecz, A. Sodor (Konkoly Observatory)
on 30 Aug 2017; 20:21 UT
Credential Certification: Jozsef Vinko (vinko@astro.as.utexas.edu)
Subjects: Optical, Supernovae, Transient
We report photometric observations of the recently discovered
optical transient MASTER OT J091344.71+762842.4 in NGC 2748
(ATel #10667), a possible supernova. The data were taken
with the 60/90 cm Schmidt telescope through Bessell B,V,R,I filters
at Konkoly Observatory, Piszkesteto, Hungary between Aug 25 and 29,
2017.
The transient is clearly present on all images at the following
position: R.A. = 09:13:44.666, Dec. = +76:28:44.51, which is
about 2" North from the position announced by Balanutsa et al.
in ATel #10667.
PSF-photometry of the OT source and several local comparison
stars, whose magnitudes were tied to their
PS1-photometry after
transforming the PS1 griz magnitudes to the Johnson-Cousins BVRI system
(Magnier et al. arXiv:1612.05242),
was computed with IRAF/DAOPHOT.
The following Vega-magnitudes have been obtained for MASTER OT in NGC 2748:
MJD B eB V eV R eR I eI
57990.79 17.26 0.14 16.38 0.11 15.77 0.12 15.30 0.11
57991.79 17.25 0.14 16.29 0.10 15.70 0.12 15.21 0.11
57993.95 16.73 0.08 15.92 0.05 15.34 0.06 14.97 0.06
57994.79 16.81 0.09 15.91 0.07 15.32 0.07 14.94 0.07
The transient appears to be brightening rapidly, consistent with a
supernova several days before maximum light. Adopting D = 19.6 Mpc distance
for the host galaxy,
NGC 2748, from NED, the latest extinction-corrected absolute magnitudes
of the OT are M_B = -14.73 (+/- 0.10), M_V = -15.63 (0.07),
M_R = -16.20 (0.08) and M_I = -16.55 (0.08). These data suggest that
the transient is probably heavily reddened by dust within its host.
Spectroscopic observations on this young transient are encouraged.
