Photometry of transients Gaia17dce and Gaia17dcv

ATel #11044; A. Simon, V. Reshetnyk (Astronomy and Space Physics Department, National Taras Shevchenko University of Kyiv, Ukraine), I. Sokolov (INASAN RAN), V. Godunova (ICAMER Observatory, Ukraine)
on 9 Dec 2017; 07:15 UT
Credential Certification: Andrew Simon (skazhenijandrew@gmail.com)

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We report BVR photometry of transients Gaia17dce and Gaia17dcv performed with the 2-m RCC telescope at the Terskol Observatory.

The bright blue hostless transient Gaia17dce was discovered by Gaia on 2017-11-27 at magnitude G = 16.67. There was no progenitor object on archival images. We detected Gaia17dce on the images taken on 2017-12-01 (MJD 58088.71). Using the AAVSO catalogue for photometric calibration we obtained the following magnitudes of the source (not corrected for the Galactic foreground extinction): B = 17.41 ± 0.07, V = 17.12 ± 0.08, R = 17.13 ± 0.05.

The blue transient Gaia17dcv was detected near the galaxy APMUKS (BJ) B005538.52-120314.2 on 2017-11-30 at magnitude G = 18.93. Follow-up observations of this object started at Terskol on 2017-12-01, just after the alert was published. CCD images were calibrated using NOMAD field stars. The following magnitudes of Gaia17dcv were derived (not corrected for the Galactic foreground extinction):

Filter	MJD	mag	errstat	MJD	mag	errstat
B	58088.757	18.37	0.06	58089.828	18.77	0.20
V	58088.756	18.74	0.05	58089.829	18.73	0.14
R	58088.755	18.85	0.03	58089.831	18.99	0.11

We acknowledge ESA Gaia, DPAC and the Photometric Science Alerts Team (http://gsaweb.ast.cam.ac.uk/alerts).