GRB 190829A
GCN Circular 25682
Subject
GRB 190829A observations in CrAO, photometry of the SN
Date
2019-09-07T10:59:13Z (7 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (IKI), V. Rumyantsev (CrAO), A. Pozanenko (IKI), S. Belkin
(IKI), E. Mazaeva (IKI) report on behalf of IKI GRB FuN collaboration:
We are observing the optical afterglow (Xu et al., GCN 25555; Lipunov
et al., GCN 25558; Kumar et al. GCNC 25560) of GRB 190829A (Fermi team,
GCN 25551; Dichiara et al., GCN 25552) at 0.0785 (Valeev et al., GCN
25565). Observations of the OA with ZTSh 2.6m telescope of CrAO started
on Aug. 30 and continued up to Sep. 6 in B and R filters.
Using masked subtraction we can compare the brightness of the OA in
different epochs. The OA is steady fading between Aug. 30 and Sep. 2.
Between the two epochs (2019-09-02T00:46:30 and 2019-09-06T00:40:50) we
clearly observe brightening of the OA (by 1.8 magnitude in R-filter)
which corresponds to the rising Supernova (Bolmer et al., GCN 25651;
Perley et al., GCN 25657; Terreran et al., GCN 25664; de Ugarte Postigo
et al., GCN 25677).
GCN Circular 25677
Subject
GRB 190829A: GTC confirmation of an associated Type Ic-BL Supernova
Date
2019-09-06T14:47:37Z (7 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), L. Izzo (DARK/NBI), C. C
Thoene, M. Blazek, K. Bensch, J. F. Agui, D. A. Kann (all
HETH/IAA-CSIC), A. L. Cabrera Lavers, N. Castro-Rodriguez (both IAC,
Grantecan), and A. Tejero Caro (Grantecan) report:
We obtained spectroscopy of GRB 190829A (Fermi GBM team, GCN #25551;
Dichiara et al., GCN #25552) with OSIRIS on the 10.4 m Gran Telescopio
Canarias on La Palma, Spain, based on Director's Discretionary Time
proposal GTC02-19BDDT. We obtained 3 x 600 s exposures each in two
grisms, R1000B and R1000R, yielding a total wavelength coverage from
3700 to 10000 AA. Observations began at 03:57 UT on 06 September 2019,
7.35 days after the trigger.
After correcting for the large amount of host-galaxy reddening, using
A_V = 1.5 mag and an SMC-like extinction curve, we find a spectrum
showing broad undulations. An excellent match is obtained vs. an
X-shooter spectrum of SN 2010bh at a similar epoch (Bufano et al., ApJ,
753, 67), especially above 5000 AA (see
https://www.iaa.csic.es/~deugarte/GRBs/190829A/GRB190829A_SN.png). We
further find a good match to a spectrum of SN 1998bw (Patat et al. 2001,
ApJ, 555, 900) taken 6.6 days before peak light (and ~ 8 days post-GRB),
but a less good match for SN 2006aj at a similar time after the GRB.
We find evidence for broad absorption lines of SiII 6355, OI 7775, and
CaII 8490, with the expansion speed of SiII being ~ 30,000 km/s, very
similar to SN 1998bw at this time after trigger. This fully confirms the
results of Terreran et al. (GCN #25664