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SALT spectroscopic classification of transient Gaia17bur as a likely dwarf nova

ATel #10610; M. Gromadzki, L. Wyrzykowski, P. Mroz, A. Hamanowicz (Warsaw University Astronomical Observatory, Poland), Z. Kostrzewa-Rutkowska (SRON, Radboud University Nijmegen), D. A.H. Buckley, E. Romero-Colmenero (South African Astronomical Observatory)
on 1 Aug 2017; 21:25 UT
Credential Certification: Lukasz Wyrzykowski (wyrzykow@astrouw.edu.pl)

Subjects: Optical, Cataclysmic Variable

The optical transient Gaia17bur (13:44:00.73, -40:28:44.22) was discovered on 2017-07-19 with G=18.8 by Gaia Science Alerts programme. Archival observations of this object by the Gaia mission shows brightness variations around G=20. This suggests the amplitude was around 1 magnitude.

A low resolution (R = 350) SALT/RSS spectrum was taken on 2017-07-28 at 18:46:55 UT, under the SALT Large Programme on transients (2016-2-LSP-001), revealing a steep blue continuum (Tbb~10,000K) with broad Balmer emission lines with FWHM of around 1400 km/s. This spectrum is typical of a cataclysmic variable and in particular a dwarf nova in quiescence.

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