Gamma-ray Burst 221024A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Oct 22 13:01:03 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1131029,   Seg_Num: 0
GRB_RA:          169.718d {+11h 18m 52s} (J2000),
                 170.025d {+11h 20m 06s} (current),
                 169.044d {+11h 16m 11s} (1950)
GRB_DEC:         +33.041d {+33d 02' 28"} (J2000),
                 +32.916d {+32d 54' 58"} (current),
                 +33.315d {+33d 18' 53"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       7588 [cnts]    Image_Peak=292 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   298     E_range: 25-100 keV
BKG_INTEN:       61526 [cnts]
BKG_TIME:        46769.90 SOD {12:59:29.90} UT
BKG_DUR:         40 [sec]
GRB_DATE:        19876 TJD;   297 DOY;   22/10/24
GRB_TIME:        46827.12 SOD {13:00:27.12} UT
GRB_PHI:         -128.57 [deg]
GRB_THETA:        34.47 [deg]
SOLN_STATUS:     0x20002003
RATE_SIGNIF:     14.31 [sigma]
IMAGE_SIGNIF:    10.22 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +2  +0  +0  +0 -52  +0 
SUN_POSTN:       208.96d {+13h 55m 51s}  -11.85d {-11d 51' 16"}
SUN_DIST:         58.17 [deg]   Sun_angle= 2.6 [hr] (West of Sun)
MOON_POSTN:      198.90d {+13h 15m 36s}   -5.61d {-05d 36' 43"}
MOON_DIST:        47.28 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      190.83, 69.17 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      156.76, 26.15 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        There is a bright star (mag=3.48) 5.90 arcmin from this position.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 245.63,-3.54 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(1.0<100sec) coincident with the FERMI_GBM event (trignum=688309233).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Oct 22 13:02:52 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1131029,   Seg_Num: 0
POINT_RA:        169.695d {+11h 18m 47s} (J2000)
POINT_DEC:       +33.069d {+33d 04' 10"} (J2000)
IMG_START_DATE:  19876 TJD;   297 DOY;   22/10/24
IMG_START_TIME:  46956.58 SOD {13:02:36.58} UT,   129.5 [sec] since BAT Trigger Time
COUNTS:          3    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Oct 22 13:04:14 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1131029,   Seg_Num: 0
GRB_RA:          169.718d {+11h 18m 52s} (J2000),
                 170.025d {+11h 20m 06s} (current),
                 169.044d {+11h 16m 11s} (1950)
GRB_DEC:         +33.041d {+33d 02' 28"} (J2000),
                 +32.916d {+32d 54' 58"} (current),
                 +33.315d {+33d 18' 53"} (1950)
GRB_DATE:        19876 TJD;   297 DOY;   22/10/24
GRB_TIME:        46827.12 SOD {13:00:27.12} UT
TRIGGER_INDEX:   298
GRB_PHI:         -128.57 [deg]
GRB_THETA:        34.47 [deg]
DELTA_TIME:      38.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x2003
RATE_SIGNIF:     14.31 [sigma]
IMAGE_SIGNIF:    10.22 [sigma]
LC_URL:          sw01131029000msb.lc
SUN_POSTN:       208.96d {+13h 55m 52s}  -11.86d {-11d 51' 19"}
SUN_DIST:         58.17 [deg]   Sun_angle= 2.6 [hr] (West of Sun)
MOON_POSTN:      198.93d {+13h 15m 42s}   -5.63d {-05d 37' 31"}
MOON_DIST:        47.30 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      190.83, 69.17 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      156.76, 26.15 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        There is a bright star (mag=3.48) 5.90 arcmin from this position.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 245.63,-3.54 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Oct 22 13:07:14 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1131029,   Seg_Num: 0
POINT_RA:        169.695d {+11h 18m 47s} (J2000)
POINT_DEC:       +33.069d {+33d 04' 10"} (J2000)
POINT_ROLL:      133.386d
IMG_START_DATE:  19876 TJD;   297 DOY;   22/10/24
IMG_START_TIME:  46954.21 SOD {13:02:34.21} UT,   127.1 [sec] since BAT Trigger Time
FILTER:          2, UVW2
BKG_MEAN:        0.165
N_STARS:         190
X_OFFSET:        475 [pixels]
Y_OFFSET:        236 [pixels]
X_MAX:           1914 [pixels]
Y_MAX:           1675 [pixels]
DET_THRESH:      4
PHOTO_THRESH:    2
SL_URL:          sw01131029000msufc0127.fits
SUN_POSTN:       208.97d {+13h 55m 52s}  -11.86d {-11d 51' 21"}
SUN_DIST:         58.21 [deg]   Sun_angle= 2.6 [hr] (West of Sun)
MOON_POSTN:      198.95d {+13h 15m 48s}   -5.64d {-05d 38' 17"}
MOON_DIST:        47.36 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      190.76, 69.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      156.73, 26.17 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Oct 22 13:07:27 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1131029,   Seg_Num: 0
POINT_RA:        169.695d {+11h 18m 47s} (J2000)
POINT_DEC:       +33.069d {+33d 04' 10"} (J2000)
POINT_ROLL:      133.386d
IMG_START_DATE:  19876 TJD;   297 DOY;   22/10/24
IMG_START_TIME:  46954.21 SOD {13:02:34.21} UT,   127.1 [sec] since BAT Trigger Time
FILTER:          2, UVW2
BKG_MEAN:        0.165
N_STARS:         190
X_OFFSET:        475 [pixels]
Y_OFFSET:        236 [pixels]
X_MAX:           1914 [pixels]
Y_MAX:           1675 [pixels]
DET_THRESH:      4
PHOTO_THRESH:    2
SL_URL:          sw01131029000msufc0127.fits
SUN_POSTN:       208.97d {+13h 55m 52s}  -11.86d {-11d 51' 22"}
SUN_DIST:         58.21 [deg]   Sun_angle= 2.6 [hr] (West of Sun)
MOON_POSTN:      198.95d {+13h 15m 49s}   -5.64d {-05d 38' 20"}
MOON_DIST:        47.36 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      190.76, 69.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      156.73, 26.17 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Oct 22 13:08:41 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1131029,   Seg_Num: 0
POINT_RA:        169.695d {+11h 18m 47s} (J2000)
POINT_DEC:       +33.069d {+33d 04' 10"} (J2000)
ROLL:            133.386d
IMG_START_DATE:  19876 TJD;   297 DOY;   22/10/24
IMG_START_TIME:  46954.21 SOD {13:02:34.21} UT,   127.1 [sec] since BAT Trigger Time
FILTER:          2, UVW2
EXPOSURE_ID:     688309384
X_OFFSET:        1034 [pixels]
Y_OFFSET:        795 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1194
Y_GRB_POS:       955
BINNING_INDEX:   1
IM_URL:          sw01131029000msuni0158.fits
SUN_POSTN:       208.97d {+13h 55m 52s}  -11.86d {-11d 51' 23"}
SUN_DIST:         58.21 [deg]   Sun_angle= 2.6 [hr] (West of Sun)
MOON_POSTN:      198.96d {+13h 15m 51s}   -5.64d {-05d 38' 39"}
MOON_DIST:        47.37 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      190.76, 69.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      156.73, 26.17 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Oct 22 13:08:56 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1131029,   Seg_Num: 0
POINT_RA:        169.695d {+11h 18m 47s} (J2000)
POINT_DEC:       +33.069d {+33d 04' 10"} (J2000)
ROLL:            133.386d
IMG_START_DATE:  19876 TJD;   297 DOY;   22/10/24
IMG_START_TIME:  46954.21 SOD {13:02:34.21} UT,   127.1 [sec] since BAT Trigger Time
FILTER:          2, UVW2
EXPOSURE_ID:     688309384
X_OFFSET:        1034 [pixels]
Y_OFFSET:        795 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1194
Y_GRB_POS:       955
BINNING_INDEX:   1
IM_URL:          sw01131029000msuni0158.fits
SUN_POSTN:       208.97d {+13h 55m 52s}  -11.86d {-11d 51' 23"}
SUN_DIST:         58.21 [deg]   Sun_angle= 2.6 [hr] (West of Sun)
MOON_POSTN:      198.97d {+13h 15m 52s}   -5.65d {-05d 38' 43"}
MOON_DIST:        47.38 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      190.76, 69.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      156.73, 26.17 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Oct 22 13:17:32 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1131029,   Seg_Num: 0
GRB_RA:          169.7413d {+11h 18m 57.91s} (J2000),
                 170.0481d {+11h 20m 11.53s} (current),
                 169.0673d {+11h 16m 16.15s} (1950)
GRB_DEC:         +33.0419d {+33d 02' 30.8"} (J2000),
                 +32.9169d {+32d 55' 00.7"} (current),
                 +33.3156d {+33d 18' 56.0"} (1950)
GRB_ERROR:       5.1 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19876 TJD;   297 DOY;   22/10/24
IMG_START_TIME:  47212.00 SOD {13:06:52.00} UT,   384.9 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       208.97d {+13h 55m 54s}  -11.86d {-11d 51' 30"}
SUN_DIST:         58.17 [deg]   Sun_angle= 2.6 [hr] (West of Sun)
MOON_POSTN:      199.04d {+13h 16m 09s}   -5.68d {-05d 40' 54"}
MOON_DIST:        47.40 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      190.82, 69.19 [deg] galactic lon,lat of the burst
ECL_COORDS:      156.78, 26.16 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        There is a bright star (mag=3.48) 6.88 arcmin from the XRT position.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.11% < P(seren) < 0.58%.

GCN Circular #32827
R. Brivio (INAF-OAB), P. D'Avanzo (INAF-OAB), M. Ferro (INAF-OAB), J.D. Gropp (PSU), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), S. Laha (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. M. Parsotan (GSFC/UMBC/CRESSTII), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M. H. Siegel (PSU) and M. A. Williams (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 13:00:27 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 221024A (trigger=1131029). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 169.718, +33.041 which is
```
   RA(J2000) = 11h 18m 52s
   Dec(J2000) = +33d 02' 28"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 30 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 13:02:36.5 UT, 129.5 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 169.74060, 33.04207 which is equivalent to:
```
   RA(J2000)  = 11h 18m 57.74s
   Dec(J2000) = +33d 02' 31.5"
```
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This location is 68 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 (2.86 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 4 (+2.22/-1.98) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 250 seconds with the UVW2 filter starting 127 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image processing failed because there is no aspect solution due to a nearby very bright star. Results from the list of sources generated on-board are not available at this time.
Burst Advocate for this burst is R. Brivio (riccardo.brivio AT inaf.it). 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 #32835
J. Wood (NASA/MSFC) reports on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 13:00:28.98 UT on 24 October 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 221024A (trigger 688309233 / 221024542). which was also detected by Swift BAT (R. Brivio et al. 2022, GCN 32827). The Fermi GBM on-ground location is consistent with the Swift BAT position.
The on-ground calculated location, using the GBM trigger data, is RA = 178.77, DEC = +38.70 (J2000 degrees, equivalent to 11h 55m, +38d 42'), with an uncertainty of 6.4 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a core-plus-tail model, with 90% of GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32]).
The angle from the Fermi LAT boresight is 84 degrees.
The GBM light curve consists of a single pulse with a duration (T90) of about 26 s (50-300 keV). The time-averaged spectrum from T0-4.1 to T0+23.6 s is adequately fit by a simple power law function with index -1.30 +/- 0.03. However, we note that there was also solar activity detected contemporaneously by GBM at this time, which impacts the fitted spectral parameters.
The event fluence (10-1000 keV) in this time interval is (3.8 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.8 s in the 10-1000 keV band is 2.8 +/- 0.3 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/"
GCN Circular #32838
Jan Strobl, Martin Jelinek, Rene Hudec, Cyril Polasek Astronomical Institute of the Academy of Sciences (ASU CAS), Ondrejov
report
With the 0.5m robotic telescope located in Ondrejov, we observed the position of the Swift rigger 1131029 or GRB 221024A (Brivio et al, 32827), starting at October 25, 3:18UT, i.e. 14.25h post GRB. In the series of unfiltered 60s exposures, we detect an uncatalogued source inside the XRT error box. The preliminary magnitude of this source is ~19.1+-0.1, the photometry is complicated by the presence of the star nu UMa in the proximity of the field.
GCN Circular #32839
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 3710 s of XRT Photon Counting mode data and 3 UVOT images for GRB 221024A, 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 = 169.74062, +33.04199 which is equivalent to:
```
RA (J2000): 11h 18m 57.75s
Dec (J2000): +33d 02' 31.2"
```
with an uncertainty of 2.6 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 #32841
V. Swain (IITB), H. Kumar (IITB), A. Kaysang (IAO), V. Bhalerao (IITB), G. C. Anupama(IIA) and S. Barway (IIA) report on behalf of the GIT team:
We observed GRB 221024A detected by Swift-BAT (R. Brivio et al., GCN #32827) with 0.7m GROWTH-India Telescope (GIT). We obtained multiple 300s exposures in the r' filter and clearly detected the afterglow in our image at R.A.= 11:18:57.78 DEC = +33:02:30.64. The photometric results follow as:
--------------------------------------------------------------------
JD (Start) | T_Start-T0(hrs) | Filter | Magnitude (AB) |
--------------------------------------------------------------------
2459877.42179 | 9.12 | r' | 18.36 +/- 0.05 |
2459877.45883 | 10.00 | r' | 18.50 +/- 0.1 |
--------------------------------------------------------------------
GIT photometry and results from Jan Strobl et al. (GCN #32838) conclude that the source is fading and is an afterglow of GRB 221024A. The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.
The GROWTH India Telescope (GIT; Kumar et al. 2022 <https://iopscience.iop.org/article/10.3847/1538-3881/ac7bea>) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
GCN Circular #32846
M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester) and R. Brivio report on behalf of the Swift-XRT team:
We have analysed 6.0 ks of XRT data for GRB 221024A (Brivio et al. GCN Circ. 32827), from 114 s to 52.5 ks after the BAT trigger. The data comprise 248 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 32839).
The late-time light curve (from T0+11.3 ks) can be modelled with a power-law decay with a decay index of alpha=1.61 (+0.20, -0.21).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.53 (+/-0.04). The best-fitting absorption column is 5.4 (+/-1.1) x 10^20 cm^-2, in excess of the Galactic value of 2.9 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.96 (+0.14, -0.13) and a best-fitting absorption column of 6.0 (+3.2, -2.9) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (3.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     6.0 (+3.2, -2.9) x 10^20 cm^-2
Galactic foreground: 2.9 x 10^20 cm^-2
Excess significance: 1.7 sigma
Photon index:	     1.96 (+0.14, -0.13)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01131029.
This circular is an official product of the Swift-XRT team.
GCN Circular #32848
N. P. M. Kuin and R. Brivio report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB221024A 127 seconds after the BAT trigger (Brivio et al., GCN Circ. 32827). The UVOT could not observe in the u,b,v or white filters due to the nearby bright star nu uMa (V=3.49, U=6.44). A source detection has been reported by Strobl et al. (GCN Circ. 32838) and by Swain et al. (GCN Circ. 32841) with r' = 18.36 at 9.12 hours after the Trigger.
UVOT obtained images in uvw1, uvm2 and uvw2. Visual inspection shows no credible source in the initial images with upper limits of 19.7 mag.
In the uvm2 filter which has no red leak we obtained deeper limits:
```
filter   tstart(s)   tstop(s) exposure 3-sigma UL
uvm2     23992       36065      609      >21.3
uvm2     51885       52503     3306      >20.3
```
The limits in the UV are about 3 mag. below the reported detections in r', which may suggest a redshift larger than 1.5.
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #32854
A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC), R. Brivio (INAF-OAB), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC), 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-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 221024A (trigger #1131029) (Brivio, et al., GCN Circ. 32827). The BAT ground-calculated position is RA, Dec = 169.702, 33.068 deg which is
```
   RA(J2000)  =  11h 18m 48.6s
   Dec(J2000) = +33d 04' 04.9"
```
with an uncertainty of 2.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%.
The mask-weighted light curve shows a rather weak pulse starting at the trigger time, peaking around T+5 seconds and decaying to baseline by about T+40 seconds. There is some low-level emission following this peak, including a possible peak In the low-energy bands at approximately T+200 seconds. The pipeline-calculated T90 (15-350 keV) is 120+-111 sec (estimated error including systematics), with the large stated error due to uncertainty in whether the possible T+200 peak contains at least 5% of the burst fluence.
The time-averaged spectrum from T+0.00 to T+221.28 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.39 +- 0.25. The fluence in the 15-150 keV band is 1.5 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+2.93 sec in the 15-150 keV band is 1.5 +- 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/1131029/BA/
GCN Circular #32859
C. Andrade (UMN), A. Iskandar (XAO), A. Klotz (IRAP-OMP), H. Peng (THU), T. Sadibekova (AIM-CEA), M.Trevor (UMD), M. Freeberg (KNC), D. Turpin (CEA), S. Antier (OCA/Artemis), A. Benkhaldoun (HAO), S. Alishov(ShAO), E. Gurbanov(ShAO), E. Hesenov (ShAO), A. Kaeouach (HAO), N. Kochiashvili (ShAO) K. Noysena (TRT), F.Guo(THU), Y.Rajabov (UBAI), N. Sasaki (OPD), Z. Vidadi (ShAO), report on behalf of the GRANDMA collaboration:
The GRANDMA telescope network responded to the Swift-BAT alert of GRB 221024A (R. Brivio et al., GCN 32827, J.P. Osborne et al. GCN 32839, M. Capalbi et al. GCN 32846, A. Y. Lien et al. GCN 32854), which is also detected by Fermi (J. Wood et al. GCN 32835).
The first observations started 22 hours after the BAT trigger time. The afterglow was reported detected within the XRT enhanced error region by different teams: J. Strobl et al. (GCN 32838) D50-telescope from ASU CAS; V. Swain et al. (GCN 32841) 0.7m GROWTH India Telescope; including UVOT observations and N. P. M. Kuin et al. (GCN 32848).
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    |  Observatory| Filter    | Upp.Mag.
____________________________________________________
22.11   |59877.463197| KNC-NMSkies | ps1/r     | 19.7
```
Most of the sites were limited by the sky visibility and the weather conditions. There is also light pollution from the nearby bright star (Nu UMa, apparent mag (V) +3.490) located at ~6' from the XRT position. Only one observation was successfully performed in the context of the Kilonova-Catcher programme (KNC), a professional-amateur collaboration within the GRANDMA project, by the T21 New Mexico skies iTelescope using filter ps1/r. The KNC image have been processed using the STDpipe and photometry was performed using field stars from the PanSTARRS1-r catalogue as reference.
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/).
GCN Circular #32863
S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), N. Pankov (HSE) report on behalf of IKI-GRB-FuN:
We observed the field of GRB 221024A (Swift: Brivio et al., GCN 32827; Fermi: J. Wood et al. GCN 32835 ) with AZT-33IK telescope of Mondy observatory starting on Oct. 26 (UT) 21:03:08. In the stacked image we detected the optical counterpart (Strobl et al., GCN 32838, Swain et al., GCN 32841, Andrade et al., GCN 32859) in coordinates (J2000) 11:18:57.58, +33:02:32.1 with uncertainities of 0.14 arcsec in both coordinates. The position of the optical counterpart is 2.3" apart from the center and within of the enhanced XRT position (Osborne et al., GCN 32839). Preliminary photometry of the field is following.
```
Date       UT start t-T0 Filter Exp. OT Err. UL(3sigma)
                    (mid, days) (s)

2022-10-26 21:03:08 2.35534 R 29*120 21.0 0.1 22.5
```
Photometry is based on the USNO-B2.0 nearby stars.
```
USNO-B1.0
RA DEC R2
11:18:51.3907200 +32:59:13.401600 16.52
11:19:04.3800000 +32:58:07.082400 17.00
```

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Jochen Greiner, last update: 27-Oct-2022 [Disclaimer]