GCN Circular 20978
Subject
GRB 170325A: optical observations, possible OT/host detection
Date
2017-04-04T20:20:06Z (7 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO), P. Minaev
(IKI), E. Klunko (ISTP), A. Volnova (IKI), M. Eselevich (ISTP) report
on behalf of larger GRB follow-up collaboration:
��e followed up the short GRB 170325A (Palmer et al., GCN 20938) with
AZT-33IK telescope of Sayan observatory (Mondy) an ZTSh telescope of
CrAO observatory. The burst was detected by GBM/Fermi (Bissaldi et al.,
GCN 20940) and also detected as 5.5 sigma non-triggered IBAS event of
0.1 s duration of SPI-ACS/INTEGRAL (see
http://grb.rssi.ru/GRB170325A/GRB170325_SPI-ACS.png).
We obtained several images in R-filter on March 26, March 29, and
April 1 and cover all 90% error box of the BAT/Fermi (Palmer et al., GCN
20938). We investigated variability of sources in the BAT/Fermi error
box between the three epochs. One source exhibits marginal fading
between first and second epochs. Preliminary photometry of the source is
following
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2017-03-26 14:10:51 1.28049 R 3600 21.94 0.15 22.2
2017-03-29 21:00:52 4.56314 R 3240 22.27 0.10 23.6
2017-04-01 15:46:59 7.35072 R 4100 22.45 0.25 22.6
the photometry is based on nearby SDSS-DR9 stars
SDSS-DR9_id R(Lupton transformations)
J082954.53+203317.9 18.69
J083002.05+203031.2 16.74
J082950.18+203013.8 18.25
J082949.90+203106.9 16.65
Coordinates of the source are (J2000) 08:29:57.677 +20:30:51.75 with
uncertainty of 0.7 arcsec in both coordinates. The finding chart can be
found in
http://grb.rssi.ru/GRB170325A/GRB170325A_Mondy_170326_2.png
http://grb.rssi.ru/GRB170325A/GRB170325A_CrAO_170329.png
The source is not presented in SDSS-DR9, but clearly visible in
r(=22.59), i(=22.10) filters, barely visible in u-filter (23.1), and not
detected in g and z of SDSS images.
We suggest the source is an afterglow and host candidates of the short
GRB 170325A.