GCN Circular 18494

V.M. Lipunov (Lomonosov Moscow State University, SAI MSU), E.S. Gorbovskoy
(SAI Lomonosow MSU), R.Rebolo (IAC), N.Budnev (API Irkutsk State Uni),
A.Tlatov (Kislovodsk Solar Station, Pulkovo), V.V.Yurkov (Blagoveschensk
State Pedagogical University)
 and D. Buckley(SAAO) behalf MASTER-team.

MASTER-Net of robotic telescope spent a great sky survey for research LVC
trigger G194575.
We have not received an automatic socket messages through GCN.
Therefore, we were not able to immediately start automatically survey
inside error box  and began  it in the manual mode at 2015-10-22 23:17:52
on the MASTER-Kislovodsk telescope,
which at that time had suitable weather condition. In the subsequent time
MASTER-II  telescopes SAAO (South Africa), IAC (Tenerife), Tunka (Baykal),
Blagoveschensk and Kislovodsk  cover approximately 9000 sq. degree of sky
due to very flat probability distributuion (which actually includes all the
sky).  The observations inside on the lobe nead 1 h RA  were greatly
complicated by the proximity of the moon. It was finally covered 87% of the
lobe nead 1 h RA and 14% of full probability. The remaining 13% of 1h lobo
are overexposed background light of the moon. 3 sigma upper limit in our
survey ranged from 17 to 20 depending on the distance to the moon and
weather conditions. The best limit, which is obtained in our survey shows
a color on a coverage map:

http://master.sai.msu.ru/static/G194575/limits2.png

We found following transitents during this survey:



1) MASTER OT J194142.51-563815.7 discovery ��� dwarf nova outburst, Amplitude
more then 4.9m.

MASTER-SAAO auto-detection system discovered OT source at (RA, Dec) = 19h
41m 42.51s -56d 38m 15.7s on 2015-10-25.80803 UT.
The OT unfiltered magnitude is m_OT=17.1 (the limit is 18.5m, 6 images),
m_OT=17.4 on 2015-10-26 18:38:50.366UT(2 images). There is no minor planet
at this place. We have reference image without OT on 2015-03-23.04023 UT
with unfiltered magnitude limit 20.2m.
There is no known optical source at this place (VIZIER database, POSS limit
is 22m). There is only Allwise source with W1=17.109, W2=17.373, W3=12.745.
So there is a dwarf nova outburst with Amplitude more then 4.9m.

The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/194142.51-563815.7_1.png

2) MASTER OT J184709.24-495633.9 discovery ��� dwarf nova outburst with
Amplitude more then 3.4m

MASTER-SAAO auto-detection system discovered OT source at (RA, Dec) = 18h
47m 09.24s -49d 56m 33.9s on 2015-10-25.79044 UT.
The OT unfiltered magnitude is 17.2m (limit is 18.3m, 4 images). There is
no minor planet at this place.
MASTER-SAAO reobserved it on 2015-10-26 18:06:20.857 , m_OT=17.7 (2
images). We have reference image without OT on 2015-02-17.102UT with
unfiltered magnitude limit 19.4m. There is USNO B1 star with B2=20.83,
R2=20.58. So there is classic dwarf nova outburst with amplitude more then
3.4m.
The discovery and reference images are available at
http://master.sai.msu.ru/static/OT/184709.24-495633.9.png


3) MASTER OT J020836.79-104018.8 discovery

MASTER-IAC auto-detection system discovered OT source at (RA, Dec) = 02h
08m 36.79s -10d 40m 18.8s on 2015-10-23.07405 UT.
The OT magnitude in I-band is 17.0m (limit 18.4m). The OT is seen in 3
images. There is no minor planet at this place. We have reference image
without OT on 2015-10-21.07257 UT with unfiltered magnitude limit 21.1m.

There is 2MASS and WISE source with J=14.873, H=14.243, K=13.851
http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=&-out.add=_r&-out.add=_RAJ%2C_DEJ&-sort=_r&-to=&-out.max=20&-meta.ucd=2&-meta.foot=1&-c=32.153291666667+-10.671888888889&-c.rs=5

The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/020836.79-104018.8.png


4). MASTER OT J060553.93+283325.6 discovery  -dwarf nova outburst with
Amplitude more then 3.9m

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 06h
05m 53.93s +28d 33m 25.6s on 2015-10-25.75079 UT.
The OT unfiltered (W=0.2B+0.8R, calibrated to USNO-B) magnitude is 15.5m
(the limit is 18.0m).
The OT is seen in 9 images.
We have reference image without OT on 2013-12-01.66689 UT with unfiltered
magnitude limit 18.9m.
There is USNO-B1 star with B2=20.53,R2=19.10,I=17.9, no JHK, so this OT is
dwarf nova outburst with Amplitude more then 3.9m.

Spectral observations are required. The discovery and reference images are
available at
http://master.sai.msu.ru/static/OT/MASTEROTJ060553.93+283325.6.jpg


5). MASTER-IAC automaticaly found the QUEST optical transient reported by
GCN Circ.18473
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  (Rabinovich et al.) inside the LIGO error region for trigger
G194575.

MASTER-IAC auto-detection system detected OT source at (RA, Dec) = 00h 11m
27.62s -06d 25m 38.0s on 2015-10-26.97009 UT  with unfiltered magnitude
m_OT= 17.0 m +-0.3 (W=0.2B+0.8R calibrated to USNO-B1). Photometry is not
very good because proximity of the Moon.

The OT is seen in 5 images. There is no minor planet at this place. We have
reference image without OT on 2015-10-09.09056 UT with 19.9 unfiltered
magnitude limit.