GCN Circular 20862
Subject
LIGO/Virgo G270580: optical observations and classification of PS and MASTER sources
Date
2017-03-14T01:28:57Z (8 years ago)
From
Alexei Pozanenko at IKI,Moscow <grbgw.iki@gmail.com>
A. Pozanenko (IKI), A. Volnova (IKI), E. Mazaeva (IKI), E. Klunko
(ISTP), A. Kusakin (AFIF), I. Reva (AFIF), V. Rumyantsev (CrAO), R.
Inasaridze (AbAO), T. Movsisyan (BAO), A. Sergeev (IRA NASU) on behalf
of IKI-GW follow-up collaboration:
We report results of photometric observations and possible
classifications of the bright SN PS17yt, PS orphan sources PS17lk,
PS17nv, PS17qk, PS17pv, PS17rc and MASTER J090737.22+611200.5 in the
field of the LIGO G270580 localizations (LIGO Scientific Collaboration
GCN 20486). Observations were conducted using telescopes/observatories
AZT-33IK/Mondy, Zeiss-1000/TSHAO, ZTSh2.6/CrAO, AS-32/AbAO, ZTA2.6/BAO
and Zeiss-1000/Koshka.
===============
PS17lk RA 09 29 58.27 Dec +15 11 58.5
We observed the source PS17lk (Huber et al., GCN 20518) taking 6
observational sets in different epochs between Jan 25 and Feb 18. All
observations were performed with filter R. We clearly detected the
source in all but one epochs. The photometry is based on nearby SDSS stars.
Observations
date Filter MJD mid Mag(Vega) err
2017-01-25 R 57778.72969 20.92 0.16
2017-01-29 R 57782.74483 >22.5 (3 sigma uplim)
2017-01-30 R 57783.70939 21.10 0.11
2017-01-31 R 57784.69874 21.22 0.12
2017-02-07 R 57791.93095 21.60 0.40
2017-02-18 R 57802.73167 21.89 0.24
The source is not detected in any SDSS frames up to the limit of r~23.1,
i~22.8. Also there is no any source in the SDSS stacked ugriz frame. We
should note, that PS17lk is located near the ecliptic plane (ecliptic
coordinates lambda = 139.955198 deg, beta = 0.391980 deg). Upper limit
on possible proper motion of the source during 25 days of observations
is 0.6 arcsec.
===============
PS17nv 09 57 41.01 +17 49 33.4
We observed the localization of the source PS17nv (Huber et al., GCN
20518) taking 3 observational sets in different nights between Jan 25
and Jan 31. All observations were performed with filter R. We did not
detect any source no one night. The photometry is based on nearby SDSS
stars.
Observations
date Filter MJD mid 3 sigma uplim
2017-01-25 R 57778.74557 >22.2
2017-01-27 R 57780.82339 >22.2
2017-01-31 R 57784.03700 >23.4
The source is not detected in any SDSS frames up to the limit of r~23.0,
i~22.4. Also there is no any source in the SDSS stacked ugriz frame. The
source is not detected neither before the discovery (SDSS frames), nor a
few days after (our observational epochs). The PS17nv is located near
the ecliptic plane (ecliptic coordinates lambda = 145.362711 deg, beta =
5.060578 deg) and might be an uncataloged asteroid.
===============
PS17pv 09 25 07.35 +50 12 28.9
We observed the source PS17pv (Huber et al., GCN 20518) taking 3
observational sets in different epochs between Jan 25 and Jan 30. All
observations were performed with filter R. We detected the source only
on Jan 30. The photometry is based on nearby SDSS stars.
Observations
date Filter MJD mid Mag(Vega) err
2017-01-25 R 57778.82847 >20.5
2017-01-28 R 57781.86958 >22.4
2017-01-30 R 57783.80134 20.74 0.11
The source is not detected in any SDSS frames up to the limit of r~23.1,
i~22.5. Also there is no any source in the SDSS stacked ugriz frame.
===============
PS17qk 09 29 12.15 +25 49 06.4
We observed the source PS17qk (Huber et al., GCN 20518) taking 8
observational sets in different epochs between Jan 25 and Feb 18. We
performed observations with filter R and in one case in filter B. We
clearly detected the source in all our observations. The photometry is
based on nearby USNO-B1.0 stars.
Observations
date Filter MJD mid Mag(Vega) err
2017-01-25 R 57778.77275 21.01 0.12
2017-01-29 R 57782.78859 20.61 0.11
2017-01-30 R 57783.74301 20.46 0.06
2017-01-31 R 57784.73083 20.36 0.05
2017-01-31 R 57784.84479 20.50 0.03
2017-01-31 B 57784.85668 20.87 0.04
2017-02-01 R 57785.77138 20.17 0.05
2017-02-18 R 57802.75716 20.55 0.07
2017-03-06 CR 57818.86623 20.53 0.09
There is no data for this region in the SDSS latest release. We did not
find any source at the position in the archival DSS2 B and R plates up
to B~21.0, R~20.5. B-R magnitude for the source is ~0.4 mag at the epoch
Jan 31 (MJD = 57784.8). The source is unlikely a Supernova.
===============
PS17rc 09 32 19.16 +47 03 38.3
We observed the source PS17rc (Huber et al., GCN 20518) taking 5
observational sets in different epochs between Jan 25 and Feb 1. We
performed observations with filter R and in one case in filter B. We
clearly detected the source in all epochs. The photometry is based on
nearby SDSS stars.
Observations
date Filter MJD mid Mag(Vega) err
2017-01-25 R 57778.81470 20.96 0.15
2017-01-30 R 57783.77229 21.04 0.10
2017-01-31 R 57784.76358 21.13 0.11
2017-01-31 R 57784.88885 21.28 0.05
2017-01-31 B 57784.87345 23.57 0.24
2017-02-01 R 57785.80742 21.28 0.09
The source is not detected in any SDSS frames as well as in stacked
ugriz. In our observations the source is red: B-R color is ~2.3 mag at
the epoch of 2017-01-3 (MJD = 57784.9). It might be a SN well after
maximum and not related to the LIGO G270580.
===============
We observed the bright SN PS17yt (Chambers et al., GCN 20512; Huber et
al., GCN 20518) between Jan. 24 and Mar. 08 in BVR filters. We clearly
detected the source in all epochs. The preliminary light curve of the SN
may be found at http://grb.rssi.ru/PS17yt/PS17yt_lc_v7.png
The photometry is based on nearby SDSS stars.
The observed maximum of the SN in B-filter is approximately at the epoch
MJD = 57788 (B=18.09 +/-0.05 at MJD=57789.74, not corrected for Galaxy
extinction).
Riess et al. (1999, AJ 118, 2668) found that for low-redshift SNs Ia the
average rise time is t_r = 19.98 +/- 0.15 days in the rest frame for
B-band light curve. Taking into account the low redshift of the SN
PS17yt z = 0.067 (Chambers et al., GCN 20512; Malesani GCN 20527), we
may conclude that the time of the SN explosion could be at MJD = 57767 -
57768, i.e. Jan. 14-15, and most probably not related to the LIGO G270580.
===============
MASTER OT J090737.22+611200.5 09 07 37.22 +61 12 00.5
We observed the source MASTER OT J090737.22+611200.5 (Lipunov et al..
LVC 20488) taking 3 observational sets in different epochs between Jan
21 and 23. We performed observations with filter R. We clearly detected
the source in all epochs. The photometry is based on nearby SDSS stars.
Observations
date Filter MJD mid Mag(Vega) err
2017-01-21 R 57774.62327 19.07 0.01
2017-01-22 R 57775.64491 19.10 0.02
2017-01-23 R 57776.63227 19.18 0.03
The source is coincident with the SDSS QSO J090737.15+611200.7 (r =
19.75 +/- 0.02) with the redshift z = 3.751227.