GRB 210210A
GCN Circular 29517
Subject
GRB 210210A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
Date
2021-02-17T14:49:35Z (5 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, S. Golenetskii, A.Lysenko, D. Svinkin, A. Ridnaya,
A. Tsvetkova, M. Ulanov, T. Cline, on behalf of the Konus-Wind team,
and A. Lien (GSFC/UMBC), report:
The long GRB 210210A (Swift-BAT trigger #1031728, T0 = T0(BAT)= 02:00:27.920 UT:
Laha et al., GCN 29444; Lien et al., GCN 29467)
was detected by Konus-Wind (KW) in the waiting mode.
A Bayesian block analysis of the KW waiting mode data in the 20-400 keV band
reveals a ~11 sigma count rate increase over background in the interval
from ~T0(BAT)-1.7 s to ~T0(BAT)+7.1 s.
The KW light curve of this burst is available
at http://www.ioffe.ru/LEA/GRBs/GRB210210A/
To derive the broad-band spectral parameters of this burst, we performed
a joint spectral analysis of the Swift/BAT data (15-150 keV) and the Konus-Wind
3-channel spectral data, which cover the energy range from ~20 keV to ~1.5 MeV.
The time-averaged spectrum, measured from T0(BAT)-1.685 s to T0(BAT)+7.147 s,
is best fit in the 15 keV - 1.5 MeV range by a power law with an exponential cutoff.
This fit gives a photon index alpha -1.68 (-0.23,+0.25), and Ep of 16.6 (-10.7,+7.2) keV
(chi^2 = 47.5/ 58 dof).
A fit to a simple power law gives a photon index of (2.52 �� 0.07), chi^2 = 58.4/ 59 dof.
The joint fit results are consistent with the Swift-BAT refined analysis (GCN 29467).
In the 15-1500 keV band, the total burst fluence, estimated from the CPL model,
is (1.2 �� 0.1)x10^-6 erg/cm^2, and the 2.944 s peak energy flux is (2.4 �� 0.2)x10^-7 erg/cm^2.
Assuming the redshift z=0.715 (de Ugarte Postigo et al., GCN 29450)
and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315,
and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the isotropic energy release E_iso to ~1.7x10^51 erg,
the isotropic luminosity L_iso to ~5.9x10^50 erg/s,
and the rest-frame peak energy of the time-integrated spectrum Ep,z to ~29 keV.
With these values, GRB 210210A is within 90% prediction bands
for both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW GRBs
with known redshifts (part II: Tsvetkova et al., ApJ, in press),
see http://www.ioffe.ru/LEA/GRBs/GRB210210A/GRB210210A_rest_frame.pdf
All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.
GCN Circular 29502
Subject
GRB 210210A: CAHA 2nd epoch and jet break confirmation
Date
2021-02-13T11:21:45Z (5 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC,
DARK/NBI), C. C. Thoene, M. Blazek, J. F. Agui Fernandez (all
HETH/IAA-CSIC), P. Minguez, and S. Pedraz (both CAHA) report:
We again observed the afterglow (Laha et al., GCN #29444, Lipunov et
al., GCN #29447, de Ugarte Postigo et al., GCN #29450, Breeveld & Laha,
GCN #29457, Strausbaugh & Cucchiara, GCN #29459, Jelinek et al., GCN
#29469, Kann et al., GCN #29476, Dimple et al., GCN #2948 of GRB 210210A
(Laha et al., GCN #29444) with CAFOS mounted on the 2.2m Calar Alto
telescope (Almeria, Spain). We obtained 6 x 600 s image in Rc. We detect
the optical afterglow faintly in the stacked Rc image.
Using the same comparison star used by de Ugarte Postigo et al., and
transforming to Rc following the equations of Lupton (2005), then
transforming back to AB magnitudes, we derive a preliminary magnitude:
Rc = 23.05 +/- 0.14 mag at 3.129261 days after the trigger.
Using the R-band magnitudes from the GCNs listed above, now also
including Dimple et al., GCN #29488, we confirm the steeper decay found
by Kann et al., GCN #29476, finding, with a host-galaxy magnitude as a
free parameter:
alpha_1 = 1.06 +/- 0.18,
alpha_1 = 2.50 +/- 0.90,
t_b = 0.45 +/- 0.23 days,
m_h = 23.19 +/- 0.27 mag (AB).
This fit can be improved with a dedicated host-galaxy observation. We
note that the X-ray light curve also shows evidence for a possible jet
break at 0.35 +0.27 -0.13 days, in agreement with our result.
GCN Circular 29488
Subject
GRB 210210A : 1.3m DFOT optical observations
Date
2021-02-12T10:22:31Z (5 years ago)
From
Dimple Panchal at ARIES, India <dimplepanchal96@gmail.com>
Dimple (ARIES), A. Ghosh (ARIES), R. Gupta (ARIES), A. Kumar (ARIES), A.
Panchal (ARIES), K. Misra (ARIES), S.B. Pandey (ARIES), Y. C. Joshi (ARIES)
report:
We observed the afterglow (Laha et al. GCN #29444, Lipunov et al. GCN
#29447, de Ugarte Postigo et al. GCN #29450, Breeveld & Laha, GCN
#29457, Strausbaugh & Cucchiara, GCN #29459, Jelinek et al. GCN
#29469, D. A. Kann et al. GCN #29476) of the GRB 210210A (Laha et al.
GCN #29444