GRB 221027B
GCN Circular 32867
Subject
GRB 221027B: Swift detection of a burst
Date
2022-10-27T19:32:47Z (3 years ago)
From
Jamie Kennea at Penn State U <jak51@psu.edu>
A. Y. Lien (U Tampa), E. Ambrosi (INAF-IASFPA), A. D'Ai (INAF-IASFPA),
V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU), N. J. Klingler (GSFC/UMBC/CRESSTII),
H. A. Krimm (NSF), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL),
T. M. Parsotan (GSFC/UMBC/CRESSTII) and B. Sbarufatti (INAF-OAB)
report on behalf of the Neil Gehrels Swift Observatory Team:
At 19:13:38 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 221027B (trigger=1131397). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 225.603, +47.448 which is
RA(J2000) = 15h 02m 25s
Dec(J2000) = +47d 26' 53"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multi-peaked
structure with a duration of about 15 sec. The peak count rate
was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 19:15:44.9 UT, 126.2 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 225.62105,
47.44193 which is equivalent to:
RA(J2000) = 15h 02m 29.05s
Dec(J2000) = +47d 26' 30.9"
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This
location is 49 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (2.88 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.4
(+1.76/-1.55) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 130 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag.
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.033.
Burst Advocate for this burst is A. Y. Lien (yarleen AT gmail.com).
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 32868
Subject
GRB 221027B: Enhanced Swift-XRT position
Date
2022-10-27T23:17:15Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1519 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 221027B, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 225.62095, +47.44205 which is equivalent
to:
RA (J2000): 15h 02m 29.03s
Dec (J2000): +47d 26' 31.4"
with an uncertainty of 2.2 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 32869
Subject
GRB 221027B: BOOTES-1 optical upper limit
Date
2022-10-28T00:02:43Z (3 years ago)
From
Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>
Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado, M. D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco, A. Reina (Univ. de Malaga) and F. Rendon (IAA-CSIC and INTA-CEDEA) on behalf of a larger collaboration, report:
Following the detection of GRB 221027B by Swift (Lien et al., GCNC 32867), the 0.3m BOOTES-1B robotic telescope in Mazagon (Huelva), southern Spain, automatically responded to this burst on Oct 27 at 19:19:30 UT (~6 min after trigger). In the co-added frame (20 x 10 s, clear filter), no source is detected within the enhanced XRT error position (Beardmore et al., GCNC 32868) down to 17.3 mag, which is consistent with the non-detection reported by UVOT (Lien et al., GCNC 32867).
We thank the staff at INTA-CEDEA for their excellent support.
GCN Circular 32870
Subject
GRB 221027B: Swift-XRT refined Analysis
Date
2022-10-28T04:26:06Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), A. Tohuvavohu
(U. Toronto), D.N. Burrows (PSU), J. D. Gropp (PSU), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), B.
Sbarufatti (INAF-OAB) and A.Y. Lien report on behalf of the Swift-XRT
team:
We have analysed 7.1 ks of XRT data for GRB 221027B (Lien et al. GCN
Circ. 32867), from 109 s to 24.9 ks after the BAT trigger. The data
comprise 8 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Beardmore et al. (GCN Circ.
32868).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.77 (+/-0.04).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.95 (+/-0.16). The
best-fitting absorption column is 1.3 (+0.5, -0.4) x 10^21 cm^-2, in
excess of the Galactic value of 2.9 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 3.5 x 10^-11 (4.3 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.3 (+0.5, -0.4) x 10^21 cm^-2
Galactic foreground: 2.9 x 10^20 cm^-2
Excess significance: 3.7 sigma
Photon index: 1.95 (+/-0.16)
If the light curve continues to decay with a power-law decay index of
0.77, the count rate at T+24 hours will be 0.015 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.2 x
10^-13 (6.5 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01131397.
This circular is an official product of the Swift-XRT team.
GCN Circular 32871
Subject
Swift GRB 221027B: Global MASTER-Net observations report
Date
2022-10-28T07:12:31Z (3 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko,
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin
(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),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov
(Blagoveschensk Educational State University)
MASTER-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB 221027B ( A. Y. Lien et al., GCN 32867) errorbox 21757 sec after notice time and 22094 sec after trigger time at 2022-10-28 01:21:53 UT, with upper limit up to 18.5 mag. The observations began at zenith distance = 79 deg. The sun altitude is -31.2 deg.
The galactic latitude b = 57 deg., longitude l = 80 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2136676
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
22185 | MASTER-Tavrida | C | 180 | 17.6 |
22185 | MASTER-Tavrida | C | 180 | 15.2 |
22376 | MASTER-Tavrida | C | 180 | 17.9 |
22376 | MASTER-Tavrida | C | 180 | 15.1 |
22662 | MASTER-Tavrida | C | 180 | 18.3 |
22662 | MASTER-Tavrida | C | 180 | 15.4 |
23028 | MASTER-Tavrida | C | 180 | 18.3 |
23028 | MASTER-Tavrida | C | 180 | 16.0 |
23985 | MASTER-Tavrida | C | 180 | 18.5 |
23985 | MASTER-Tavrida | C | 180 | 18.0 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 32873
Subject
GRB 221027B: FRAM-ORM and Ondrejov SBT optical limits
Date
2022-10-28T12:45:08Z (3 years ago)
From
Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>
Martin Jelinek, Jan Strobl, Rene Hudec and Cyril Polasek
(ASU CAS Ondrejov, CZ),
Sergey Karpov, Martin Masek, Petr Janecek, Jakub Jurysek,
Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza
(Institute of Physics, Prague, CZ)
report:
The 2x20cm robotic telescope BART-SBT in Ondrejov (CZ) reacted robotically
to the Swift alert of GRB221027B (Lien et al., GCNC 32867 and Perri et al.
GCNC 32870, GCNC 29119 and 29124), obtaining a series of 12s unfiltered
frames at 19:19:46 UT, i.e. 367s post trigger.
The 25cm robotic telescope FRAM-ORM at La Palma (Spain) reacted to the same
alert, providing a series of 60s unfiltered images from 19:28:20 UT, i.e.
882s post trigger.
Similarly to Hu et al. (GCNC 32869) and Lipunov et al. (GCNC 32871), we do
not detect any new or strongly variable source neither in single or in
combined frames with the following limits:
Tel. T-T0[mid,s] Texp[s] Limit[ABmag] Note
SBT 374 12 <15.5 (similar during the following
30 min)
SBT 494 240 <17.0
SBT 674 600 <17.3
SBT 1574 2400 <17.7
FRAM 912 60 <17.0 (similar next 60 minutes)
FRAM 1238 10x60 <18.0
GCN Circular 32875
Subject
GRB 221027B: Swift/UVOT Upper Limits
Date
2022-10-28T15:11:15Z (3 years ago)
From
Alexander Belles at PSU/Swift <aub1461@psu.edu>
A. Belles (PSU) and A. Y. Lien (U. Tampa)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 221027B
131 s after the BAT trigger (Lien et al., GCN Circ. 32867).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 32868)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 131 281 147 >21.1
u_FC 344 594 246 >20.2
white 131 1544 392 >21.5
v 673 1594 117 >19.2
b 599 1520 97 >19.4
u 344 1661 335 >20.4
w1 722 1644 97 >18.8
m2 698 718 19 >17.6
w2 111 841 30 >19.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.033 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 32880
Subject
GRB 221027B: COATLI Upper Limits
Date
2022-10-28T18:36:57Z (3 years ago)
From
Rosa Leticia Becerra Godinez at Inst. de Astronoma,UNAM <rbecerra@astro.unam.mx>
Rosa L. Becerra (UNAM), Alan M. Watson (UNAM), Nat Butler (ASU), Simone
Dichiara (PSU), Tzveti Dimitrova (ASU), Oc��lotl L��pez (UNAM), Diego
Gonz��lez (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Margarita
Pereyra (UNAM), Eleonora Troja (UTV/ASU) and report:
We observed the field of the GRB 221027B (Lien et al., GCN Circ. 32867)
with the COATLI 50-cm telescope and HUITZI f/8 imager at the Observatorio
Astron��mico Nacional on the Sierra de San Pedro M��rtir (
http://coatli.astroscu.unam.mx) from 2022-10-28 01:47 UTC to 02:13 UTC (6.6
hours after the trigger), obtaining a total of 750 seconds of exposure in
the r filter.
We do not detect any uncataloged sources within the XRT error region
(Beardmore et al., GCN Circ. 32868) to a 3-sigma limit of r > 21.4 mag.
Our photometry is calibrated against the Pan-STARRS1 catalog, is on an
approximate AB system, and is not corrected for Galactic extinction in the
direction of the GRB.
We thank the COATLI/HUITZI technical team and the staff of the Observatorio
Astron��mico Nacional.
GCN Circular 32892
Subject
GRB 221027B: Swift-BAT refined analysis
Date
2022-10-30T16:03:48Z (3 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), D. M. Palmer (LANL),
T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 221027B (trigger #1131397)
(Lien et al., GCN Circ. 32867). The BAT ground-calculated position is
RA, Dec = 225.601, 47.451 deg which is
RA(J2000) = 15h 02m 24.2s
Dec(J2000) = +47d 27' 04.4"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 45%.
The mask-weighted light curve shows a structure with two pulses that start
at ~T-6 s and end at ~T+4 s. The first weaker peak occurs at ~T-5 s,
followed by the main peak that occurs at ~T0. T90 (15-350 keV)
is 8.66 +- 1.10 sec (estimated error including systematics).
The time-averaged spectrum from T-5.98 to T+4.20 sec is best fit
by a simple power-law model. The power law index of the
time-averaged spectrum is 2.39 +- 0.19. The fluence in
the 15-150 keV band is 5.8 +- 0.6 x 10^-7 erg/cm2. The 1-sec peak
photon flux measured from T-0.08 sec in the 15-150 keV band
is 3.4 +- 0.4 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/1131397/BA/
GCN Circular 32905
Subject
GRB 221027B: GRANDMA observations
Date
2022-11-03T14:53:01Z (3 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
N. Kochiashvili (AbAO), Z. Vidadi (ShAO), D. A. Kann (Goethe Univ.),
P. Gokuldass (Florida Tech.), S. Beradze (AbAO), Sh. Aghayeva (ShAO),
R. Le Montagner (IJCLab), C. Rinner, Z. Benkhaldoun (OUCA),
S. Antier (OCA/Artemis), J. Ali, A. Kaouech (OUCA/KNC), and Sergey
Karpov
(FZU) report on behalf of the GRANDMA collaboration:
The GRANDMA telescope network responded to the Swift-BAT alert of
GRB 221027B (Lien et al., GCN 32867, Beardmore et al., GCN 32868,
Perri et al., GCN 32870, Markwardt et al., GCN 32892). No optical
afterglow consistent with the XRT position (Beardmore et al., GCN
32868) is detected by Swift in the initial UVOT exposures (Belles &
Lien, GCN 32875).
The first observations started 23.8 hours after the BAT trigger time.
The optical counterpart of the afterglow was not detected in our
observations.
In the following table we report the preliminary photometry of our
observations. Upper limits are reported at the 5-sigma limit,
in the AB system.
T-T0 (hr)| MJD | Obser. |Exposure | Filter | Upp.Lim.
-----------------------------------------------------------------
23.7956 | 59880.79262 | KNC-HAO | 15 x 120 s | L | 20.5
HAO data have been calibrated with PS1 catalog. Values are
not corrected for the Galactic extinction E(B-V) = 0.0262 mag
(Schlafly & Finkbeiner 2011).
Our upper limits are in agreement with other non-detections from
Swift UVOT (Belles & Lien, GCN 32875), BOOTES-1 (Hu et al., GCN
32869), MASTER (Lipunov et al., GCN 32871), BART-SBT and FRAM-ORM
(Jelinek et al., GCN 32873), and COATLI (Becerra et al., GCN 32880).
GRANDMA is a worldwide coordinated telescope network
(grandma.ijclab.in2p3.fr) devoted to the observation of transients
in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS
497, 5518). Kilonova-Catcher (KNC) is the citizen science program of
GRANDMA (http://kilonovacatcher.in2p3.fr/).