| Summary table |
|---|
| Variable |
Value |
Source |
| GRB_name_Fermi |
GRB230911132 |
|
| T0 |
3:09:30.060 UTC |
Fermi_GBM |
| ra |
57.5027° |
GCN_circulars,Swift-XRT Other |
| decl |
-29.8259° |
GCN_circulars,Swift-XRT Other |
| T90 |
35.84 s |
Fermi_GBM |
| T90_error |
1.448 s |
Fermi_GBM |
| T90_start |
3:09:30.060 UTC |
Fermi_GBM |
| fluence |
4.44e-06 erg/cm² |
Fermi_GBM |
| fluence_error |
2.83e-08 erg/cm² |
Fermi_GBM |
| T100 |
35.84 s |
|
| GBM_located |
False |
|
| mjd |
60198.13159791667 |
Fermi_GBM |
| Fermi GBM table |
|---|
| GRB_name_Fermi |
GRB230911132 |
| trigger_name |
bn230911132 |
| ra |
57.5025° |
| decl |
-29.8258° |
| pos_error |
3.96e+00° |
| datum |
2023-09-11 |
| t_trigger |
3:09:32.876 UTC |
| T90 |
35.84 s |
| T90_error |
1.448 s |
| T90_start |
3:09:30.060 UTC |
| fluence |
4.44e-06 erg/cm² |
| fluence_error |
2.83e-08 erg/cm² |
| flux_1024 |
3.68e+00 erg/cm²/s |
| flux_1024_error |
2.27e-01 erg/cm²/s |
| flux_1024_time |
2.05e+00 erg/cm²/s |
| flux_64 |
5.05e+00 erg/cm²/s |
| flux_64_error |
9.95e-01 erg/cm²/s |
| IPN table |
|---|
| GRB_name |
GRB230911A |
| ra |
57.5042° |
| decl |
-29.8333° |
| pos_error |
4.00e+00° |
| GCN 34652 table |
|---|
| GRB_name |
GRB230911A |
| GCN_number |
34652 |
| Detection_method |
Fermi GBM final loc |
| t_trigger |
3:09:32 UTC |
| ra |
59.8000° |
| decl |
-34.4000° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 34652
SUBJECT: GRB 230911A: Fermi GBM Final Real-time Localization
DATE: 23/09/11 03:20:04 GMT
FROM: Fermi GBM Team at MSFC/Fermi-GBM
The Fermi GBM team reports the detection of a likely LONG GRB
At 03:09:32 UT on 11 Sep 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230911A (trigger 716094577.87568 / 230911132).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 59.8, Dec = -34.4 (J2000 degrees, equivalent to J2000 03h 59m, -34d 23'), with a statistical uncertainty of 4.1 degrees.
The angle from the Fermi LAT boresight is 50.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230911132/quicklook/glg_skymap_all_bn230911132.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230911132/quicklook/glg_healpix_all_bn230911132.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230911132/quicklook/glg_lc_medres34_bn230911132.gif
|
| GCN 34681 table |
|---|
| GRB_name |
GRB230911A |
| GCN_number |
34681 |
| Detection_method |
Optical |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 34681
SUBJECT: GRB 230911A: GOTO optical counterpart candidate
DATE: 23/09/13 10:07:56 GMT
FROM: Sergey Belkin at Monash University
S. Belkin; B. P. Gompertz; A. Kumar; K. Ackley; K. Wiersema; D. O’Neill; T. Killestein; R. Starling; M. J. Dyer; J. Lyman; K. Ulaczyk; F. Jimenez-Ibarra; D. Steeghs; D. K. Galloway; V. Dhillon; P. O'Brien; G. Ramsay; K. Noysena; R. Kotak; R. P. Breton; L. K. Nuttall; E. Pall'e and D. Pollacco report on behalf of the GOTO collaboration:
We report on observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) in response to GRB 230911A (Fermi GBM team, GCN 34652). Observations were performed by GOTO North and South between 04:19:47 UT on 2023-09-11 and 17:08:39 UT on 2023-09-12 (1.17 to 37.98 hours after trigger). Each observation consisted of 4x90s exposures in the GOTO L-band (400-700 nm).
Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using recent survey observations of the same pointings. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogues. Human vetting was carried out in real time on any candidates that passed the above checks.
We identify one candidate optical counterpart consistent within the GBM 90% localisation region. We find no evidence of this source prior to the GRB trigger time in previous GOTO observations, the ZTF observations provided by the Lasair broker (Smith et al. 2019), or the ATLAS forced photometry server (Shingles et al. 2021). However, we caution that the last available observation of the field was taken by ATLAS nine days before the GRB trigger.
Name | RA(J2000) | Dec(J2000) | Filter | Mag(AB) | t - trig(hrs)
GOTO23akf | 03:50:00.51 | -29:49:30.66 | L | 19.22 +/- 0.10 | 1.17
This source is seen to decay as a power-law with an index of 0.61 +/- 0.07 across 7 epochs of observations. No object is present at this position in the Legacy Survey (Dey et al. 2019).
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC). |
| GCN 34684 table |
|---|
| GRB_name |
GRB230911A |
| GCN_number |
34684 |
| Detection_method |
Swift Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 34684
SUBJECT: GRB 230911A: Swift ToO observations
DATE: 23/09/13 14:57:43 GMT
FROM: Phil Evans at U of Leicester
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Fermi/GBM GRB 230911A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021622
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/GBM event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a
GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
|
| GCN 34702 table |
|---|
| GRB_name |
GRB230911A |
| GCN_number |
34702 |
| Detection_method |
Swift-XRT Other |
| ra |
57.5027° |
| decl |
-29.8259° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 34702
SUBJECT: GRB 230911A: Swift-XRT afterglow detection
DATE: 23/09/15 06:29:37 GMT
FROM: Phil Evans at U of Leicester
P. D'Avanzo (INAF-OAB), D.N. Burrows (PSU), J. D. Gropp (PSU), S.
Dichiara (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U.
Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) and
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the
Fermi/GBM-detected burst GRB 230911A, collecting 2.8 ks of Photon
Counting (PC) mode data between T0+215.5 ks and T0+326.2 ks.
An uncatalogued X-ray source is detected consistent with the GOTO
position (GCN Circ. 34681) of the fading optical counterpart candidate,
and this is therefore believed to be the afterglow. The position of
this source (astrometrically enhanced by using the XRT-UVOT alignment
and matching UVOT field sources to the USNO-B1 catalogue) is RA,
Dec=57.5027, -29.8259 which is equivalent to:
RA (J2000): 03:50:0.65
Dec(J2000): -29:49:33.2
with an uncertainty of 3.4 arcsec (radius, 90% confidence). Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and
Evans et al. (2009, MNRAS, 397, 177). This position is 3.1 arcsec from
the GOTO position.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00021622.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021622.
This circular is an official product of the Swift-XRT team.
|
| GCN 34720 table |
|---|
| GRB_name |
GRB230911A |
| GCN_number |
34720 |
| Detection_method |
Fermi GBM Det |
| t_trigger |
3:09:32.880 UTC |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 34720
SUBJECT: GRB 230911A: Fermi GBM Observation
DATE: 23/09/17 00:27:58 GMT
FROM: Oliver J Roberts at USRA/NASA
O.J. Roberts (USRA/NASA-MSFC) and C. Meegan (UAH)
report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 03:09:32.88 UT on 11 September 2023, the
Fermi Gamma-ray Burst Monitor (GBM) triggered and located
GRB 230911A (trigger 716094577/230911132), which was also
detected by Swift/XRT (P. D'Avanzo et al. 2023, GCN 34702)
and GOTO (S. Belkin et al. 2023, GCN 34681). The Fermi GBM
Final Real-time Localization reported in GCN 34652 is
consistent with the Swift-XRT and GOTO localizations.
The angle from the Fermi LAT boresight is 54 degrees.
The GBM light curve consists of a single peak with a
duration (T90) of about 36 s (50-300 keV). The time-averaged
spectrum from T0-4 to T0+30 s is best fit by a Band function
with Epeak= 98 +/- 21 keV, alpha = -1.1 +/- 0.1 and
beta = -2.0 +/- 0.1.
The event fluence (10-1000 keV) in this time interval is
(6.2 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.0 s in the 10-1000 keV band is 3.7 +/- 0.2 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" |