[vsnet-alert 22909] TCP J15472959-0532144: new transient (12.1 mag) in Libra

Sun Dec 30 19:09:05 JST 2018

TCP J15472959-0532144  (UG:)

Discovery details:
R.A. 15h47m29.59s, Decl. -05°32'14.4" (J2000.0)
2018 Dec. 29.8217 UT, 12.1 mag (CCD, unfiltered)
Discoverer: Hideo Nishimura (Shizuoka-ken, Japan)

2018 12 29.822 UT
Discovered by H. Nishimura, Shizuoka-ken, Japan,
on three frames with 30 second exposure using
Canon EOS 6D digital camera + 200-mm f/3.2 lens
under the limiting mag = 15, who writes nothing
is visible at this location on a frame taken on
2018 Dec. 20.867 UT with limit mag.= 13 and
there is a star (mag = 18.5) at this location.
Also S. Kaneko, Shizuoka-ken, reports no star
was visible on two frames (limit mag = 14.4)
taken 2018 Dec. 28.843 UT.

2018 12 30.12 UT
A progenitor candidate from Gaia DR2 is 5" away
at R.A. 15h47m29.838s, Decl. -05°32'18.10"
(equinox J2000.0, epoch 2015.5; Gmag. 17.44,
parallax 2.0059 ± 0.1161 mas, distance ~0.49 kpc).
Other designations are CSS_J154729.8-053218
(Vmag. range 16.8-17.3), USNO-A2.0 0825-08927905
(Bmag. 18.5, Rmag. 17.2), USNO-B1.0 0844-0276155,
PSO J154729.843-053218.154 (gmag. 18.83, rmag.
17.82), GSC2.3 S89H006806 (Fmag. 17.60),
2MASS J15472984-0532182, GALEX J154729.8-053218
(nuv_mag. 21.9), etc.
No previous outbursts were detected by the
ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788
...48S and Kochanek et al. 2017PASP..129j4502K)
at the transient's position between 2012 March 17
and 2018 September 22; complete light curve at
https://asas-sn.osu.edu/light_curves/2308153f-5f15-4fdc-a525-dababb4df431
Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

http://www.cbat.eps.harvard.edu/unconf/followups/J15472959-0532144.html

Precise astrometry, spectroscopy, and multiband
(and time-resolved) photometry are urgently
required.

Clear skies,
Patrick