- GCN Circular #28825
B. Sbarufatti (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU),
N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester)
and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels
Swift Observatory Team:
At 17:33:46 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 201104B (trigger=1004168). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 5.217, 7.820 which is
RA(J2000) = 00h 20m 52s
Dec(J2000) = 07d 49' 12"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). Due to GCN downtime, no BAT light curves are
available at this moment.
The XRT began observing the field at 17:35:28.2 UT, 102 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec = 5.21528, 7.84257 which is equivalent to:
RA(J2000) = 00h 20m 51.7s
Dec(J2000) = +07d 50' 33.3"
with an uncertainty of 5 arcseconds (radius, 90% containment). This
location is 81.5 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.
Due to GCN downtime, no UVOT data are available at this time.
Burst Advocate for this burst is B. Sbarufatti (bxs60 AT psu.edu).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)
- GCN Circular #28826
V. Lipunov, V.Kornilov, E.Gorbovskoy, N.Tiurina, P.Balanutsa,A.Kuznetsov,K.Zhirkov, F.Balakin,
V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, A.Chasovnikov,A.Pozdnyakov,
V.Topolev, D.Cheryasov(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O.A. Gres, N.M. Budnev (Irkutsk State University, API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov, Yu. Sergienko (Blagoveschensk Educational State University)
MASTER-SAAO started GRB 201104B (Sbarufatti et al. GCN 28825, Ttrig=2020-11-04 17:33:46) observation by
MASTER-II (2x4sq.deg.) in 2020-11-04 19:14:43UT (unfiltered, manual pointing)
and by
MASTER very wide field cameras (Lipunov et al. 2010, Advances in Astronomy,vol.2010, 30L),
started at 48deg. altitude in clouds (the sun altitude was -25deg)
There is no OT at Swift-XRT position with mlim=16.1
Observation and reduction will continue.
- GCN Circular #28827
F. E. Marshall (NASA/GSFC), S. R. Oates (U.Warwick) and B. Sbarufatti (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 201104B
56 s after the BAT trigger (Sbarufatti et al., GCN Circ. 28825).
A source consistent with the XRT position
(Sbarufatti et al. GCN Circ. 28825)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 00:20:51.65 = 5.21520 (deg.)
Dec (J2000) = +07:50:29.4 = 7.84150 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).
Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 56 206 147 18.63 +/- 0.06
u 268 459 188 19.45 +/- 0.23
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.045 in the direction of the burst
(Schlegel et al. 1998).
- GCN Circular #28839
A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
B. Sbarufatti (PSU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+302 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 201104B (trigger #1004168)
(Sbarufatti et al., GCN Circ. 28825). The BAT ground-calculated position is
RA, Dec = 5.215, 7.834 deg which is
RA(J2000) = 00h 20m 51.5s
Dec(J2000) = +07d 50' 03.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 53%.
The mask-weighted light curve shows several overlapping pulses that
start at ~T-9 s and end at ~T+1 s. The main peak occurs at ~T-8 s.
T90 (15-350 keV) is 8.66 +- 0.16 sec (estimated error including
systematics).
The time-averaged spectrum from T-8.86 to T+0.88 sec is best fit
by a simple power-law model. The power law index of the time-averaged
spectrum is 1.47 +- 0.07. The fluence in the 15-150 keV band
is 1.8 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from
T-8.52 sec in the 15-150 keV band is 4.1 +- 0.3 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1004168/BA/
- GCN Circular #28840
J.-B. Vielfaure (GEPI, Paris Observatory), D. B. Malesani (DTU Space),
D. A. Kann (HETH/IAA-CSIC), B. Sbarufatti (PSU), N. R. Tanvir (Univ.
Leicester), and D. H. Hartmann (Clemson University) report on behalf of
the Stargate Consortium:
We observed the optical afterglow (Marshall et al., GCN 28827) of GRB
201104B (Sbarufatti et al., GCN 28825) using the ESO VLT UT3 (Melipal)
equipped with the X-shooter spectrograph. Our spectra cover the
wavelength range 3000-21000 AA, and consist of 2 exposures of 1200 s
each. The observation mid-time was 2020 Nov 5.0831 UT (8.431 hr after
the GRB).
In a 60 s image taken with the acquisition camera on Nov 5.0596 UT, we
detect the optical afterglow, for which we measure a magnitude r = 21.01
+/- 0.02 mag (AB magnitude, calibrated against nearby stars from the
Pan-STARRS catalog; Chambers et al. 2016, arXiv:1612.05560).
We clearly detect continuum over the entire wavelength range. A trough
is visible around 3590 AA, which we identify as due to H I. From
detection of multiple absorption features, which we interpret as due to
SiII, CI, CII, SiIV, CIV, FeII, AlII, AlIII, MgII, we infer a redshift z
= 1.954. In particular, fine structure lines from Fe II* are visible,
which confirm the association of the absorption system with the GRB.
Emission lines are also detected, which we interpret as due to [O II],
[O III], ad Halpha at the same redshift.
We acknowledge excellent support from the ESO observing staff in
Paranal, in particular Florian Rodler.
- GCN Circular #28850
J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A.
Melandri (INAF-OAB), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB) and
B. Sbarufatti report on behalf of the Swift-XRT team:
We have analysed 4.9 ks of XRT data for GRB 201104B (Sbarufatti et al.
GCN Circ. 28825), from 105 s to 131.7 ks after the BAT trigger. The
data comprise 347 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. Using 546 s of PC mode data and 3 UVOT
images, we find an enhanced XRT position (using the XRT-UVOT alignment
and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec =
5.21441, +7.84185 which is equivalent to:
RA (J2000): 00h 20m 51.46s
Dec(J2000): +07d 50' 30.7"
with an uncertainty of 2.3 arcsec (radius, 90% confidence).
The light curve can be modelled with an initial power-law decay with an
index of alpha=0.11 (+0.11, -0.12), followed by a break at T+338 s to
an alpha of 1.21 (+0.05, -0.04).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.80 (+/-0.07). The
best-fitting absorption column is 1.12 (+0.30, -0.28) x 10^22 cm^-2,
at a redshift of 1.954, in addition to the Galactic value of 5.7 x
10^20 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 3.7 x 10^-11 (4.5 x 10^-11) erg cm^-2 count^-1.
A summary of the WT-mode spectrum is thus:
Galactic foreground: 5.7 x 10^20 cm^-2
Intrinsic column: 1.12 (+0.30, -0.28) x 10^22 cm^-2 at z=1.954
Photon index: 1.80 (+/-0.07)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01004168.
This circular is an official product of the Swift-XRT team.
- GCN Circular #28851
S. R. Oates (U.Birmingham) and B. Sbarufatti (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 201104B
56 s after the BAT trigger (Sbarufatti et al., GCN Circ. 28825).
A source consistent with the XRT position (Sbarufatti et al. GCN Circ. 28825)
and UVOT position (Marshall et al. GCN Circ. 28827) is detected in the initial UVOT exposures.
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (FC) 56 206 147 17.98 +/- 0.05
white 20890 21385 484 >21.1
b 3718 3777 57 >19.0
u (FC) 268 459 188 18.72 +/- 0.16
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.048 in the direction of the burst
(Schlegel et al. 1998).
- GCN Circular #28852
S. Belkin (IKI), N. Pankov (HSE), I. Reva (FAPHI), A. Pozanenko (IKI)
report on behalf of GRB-IKI-FuN:
We observed the field of GRB 201104B (Sbarufatti et al., GCN 28825)
with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory
starting on Nov. 05 (UT) 12:51:33.
The optical afterglow (Marshall et al., GCN 28827; Vielfaure et al.,
GCN 28840; Oates et al., GCN 28851) at redshift z = 1.954 (Vielfaure
et al., GCN 28840) is detected in stacked image in R-filter. Preliminary
photometry of the afterglow is following.
Date UT start t-T0 Filter Exp. OT Err. UL(3 sigma)
(mid, days) (s)
2020-11-05 12:51:33 0.82641 R 43*90 21.20 0.1 22.2
The photometry is based on nearby USNO-B1.0 stars.
USNO-B1.0_id R2
0979-0003163 17.51
0979-0003223 17.47
We note the presence of a galaxy 3.6" South-East from the afterglow. The
galaxy is clearly visible in Pan-STARRS and SDSS and detected in
USNO-B1.0, PS1 and SDSS DR12 (J002051.50+075026.5).
- GCN Circular #28856
S. Belkin (IKI), A. Zhornichenko (KIAM), A. Pozanenko (IKI), V.
Agletdinov (KIAM), Sh. Ehgamberdiev (UBAI) report on behalf of IKI-GRB-FuN:
We observed the field of GRB 201104B (Sbarufatti et al., GCN 28825)
with Kitab-ISON RC-36 telescope in Clear filter. Observation started
on Nov. 4 (UT) 18:44:28, i.e. 77 minutes after trigger.
The optical afterglow (Marshall et al., GCN 28827; Vielfaure et al.,
GCN 28840; Oates et al., GCN 28851) at redshift z = 1.954 (Vielfaure et
al., GCN 28840) is marginally (S/N = 1.8) detected in stacked image.
Preliminary photometry of the afterglow is following.
Date, UT start, t-T0, Exp., Filter, OT, S/N UL(3 sigma)
(mid, days)
2020-11-04 18:44:28 0.0741 72*60 CR 20.4 1.8 20.0
The photometry is based on nearby USNO-B1.0 stars, R magnitude.
USNO-B1.0_id R2
0979-0003163 17.51
0979-0003223 17.47
- GCN Circular #28860
Rahul Gupta (ARIES), Dimple (ARIES), Amit Kumar (ARIES), Ankur Ghosh (ARIES), Amar Aryan (ARIES), Shubham Kishore (ARIES) , Shashi B. Pandey (ARIES), Kuntal Misra (ARIES), and Alok C. Gupta (ARIES ) report:
We observed the optical afterglow ( Marshall et al., GCN 28827 ; Vielfaure et al., GCN 28840; Oates et al., GCN 28851; and Belkin et al., GCN 28852, GCN 28856) of Swift triggered GRB 201104B (Sbarufatti et al., GCN 28825) using the 1.3m Devasthal Fast Optical Telescope (DFOT) at Devasthal observatory of Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2020-11-05 at 17:44:45 UT . Multiple frames having an exposure time of 60 s were taken in the R filter. We clearly detected the optical counterpart in the stacked images.
The preliminary photometric estimate of the afterglow in the stacked images is the following :
Date Start_UT T_start-T0 (hrs) Filter Exp time (s) Magnitude Mag_err
------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------
2020-11-05 17:44:45 24.18 R 30*60 22.40 0.23
------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------
The magnitude is not corrected for the Galactic and Host extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalog.
This circular may be cited.
- GCN Circular #28870
R. Hosokawa, R. Adachi, K. L. Murata, M. Niwano, F. Ogawa, N.
Nakamura, N. Ito, S. Ogata, H. Takamatsu, H. Hara, Y. Yatsu, and N.
Kawai (TokyoTech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 201104B (B. Sbarufatti et al., GCN
#28825) with the optical three color (g', Rc, and Ic) CCD cameras
attached to the MITSuME 50 cm telescope of Akeno Observatory,
Yamanashi, Japan.
The observation with a series of 60 sec exposures started at
2020-11-05 08:14:33 UT. The first 29 images were heavily affected by
twilight at Akeno Observatory. We marginally detected the point source
at the position consistent with the afterglow detected previously
(Marshall et al., GCN #28827, Vielfaure et al., GCN #28840, Oates et
al., GCN #28851, Belkin et al., GCN #28852, Belkin et al., GCN #28856,
and Gupta et al., GCN #28860).
We measured the magnitudes as follows.
T0+[hour] MID-UT T-EXP[sec] measured magnitudes
------------------------------------------------------------------------------------------------
15.2 2020-11-05 12:59:59 21360 g'=21.5+/-0.3, Rc=20.7+/-0.2, Ic=20.3+/-0.3
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used the PS1 catalog for flux calibration.
The magnitudes are expressed in the AB system.
The images were processed in real-time through the MITSuME GPU
reduction pipeline (Niwano et al.,
https://doi.org/10.1093/pasj/psaa091,
https://arxiv.org/abs/2008.11486; https://github.com/MNiwano/Eclaire).
- GCN Circular #28871
S. Belkin (IKI), A. Kusakin (FAP), N. Pankov (HSE), I. Reva (FAP), A.
Pozanenko (IKI) report on behalf of GRB-IKI-FuN:
We continued observations of the GRB 201104B (Sbarufatti et al., GCN
28825) with Zeiss-1000 1-m telescope of Tien Shan Astronomical
Observatory starting on Nov. 06 (UT) 15:04:58.
The optical afterglow (Marshall et al., GCN 28827; Vielfaure et al.,
GCN 28840; Oates et al., GCN 28851; Belkin et al., GCNs 28852, 28856;
Gupta et al., GCN 28860; Hosokawa et al., GCN 28870) at redshift z =
1.954 (Vielfaure et al., GCN 28840) is detected in stacked image in
R-filter. Preliminary photometry of the afterglow is following.
Date UT start t-T0 Filter Exp. OT Err. UL(3 sigma)
(mid, days) (s)
2020-11-06 15:04:58 1.92271 R 50*90 22.20 0.21 22.4
The photometry is based on nearby USNO-B1.0 stars.
USNO-B1.0_id R2
0979-0003163 17.51
0979-0003223 17.47
- GCN Circular #29198
S. Belkin (IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO), O. Burhonov
(UBAI), Sh. Ehgamberdiev (UBAI) report on behalf of IKI GRB FuN:
We observed GRB 201104B (Sbarufatti et al., GCN 28825) with AZT-22
telescope of Maidanak Observatory and ZTSh telescope of CrAO.
The optical afterglow (Marshall et al., GCN 28827; Vielfaure et al.,
GCN 28840; Oates et al., GCN 28851; Belkin et al., GCNs 28852, 28856,
28871; Gupta et al., GCN 28860; Hosokawa et al., GCN 28870) at redshift
z = 1.954 (Vielfaure et al., GCN 28840) is detected in stacked images.
Preliminary photometry of the afterglow is following.
Date UT start t-T0 Filter Exp. OT Err. UL(3 sigma)
(mid, days) (s)
2020-11-09 15:57:43 4.95413 R 12*300 22.89 0.09 24.3 AZT-22
2020-11-13 19:50:05 9.12784 R 45*120 23.20 0.12 24.0 ZTSh
The photometry is based on nearby USNO-B1.0 stars.
A light curve base on our observations including reported earlier
(Belkin et al., GCNs 28852, 28856, 28871) can be found in
http://grb.rssi.ru/GRB201104B/GRB201104B_LC_R.png
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