Gamma-ray Burst 220909A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 09 Sep 22 06:52:42 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     684399138
GRB_RA:           70.267d {+04h 41m 04s} (J2000),
                  70.415d {+04h 41m 40s} (current),
                  69.941d {+04h 39m 46s} (1950)
GRB_DEC:         -50.183d {-50d 10' 59"} (J2000),
                 -50.141d {-50d 08' 26"} (current),
                 -50.278d {-50d 16' 40"} (1950)
GRB_ERROR:       15.88 [deg radius, statistical plus systematic]
GRB_INTEN:       62 [cnts/sec]
DATA_SIGNIF:     4.70 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        19831 TJD;   252 DOY;   22/09/09
GRB_TIME:        24733.82 SOD {06:52:13.82} UT
GRB_PHI:          45.00 [deg]
GRB_THETA:       160.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.73
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      58%  GRB
2nd_MOST_LIKELY:  40%  Distant Particles
DETECTORS:       1,0,1, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       167.66d {+11h 10m 38s}   +5.29d {+05d 17' 33"}
SUN_DIST:         98.70 [deg]   Sun_angle= 6.5 [hr] (West of Sun)
MOON_POSTN:      335.05d {+22h 20m 12s}  -15.55d {-15d 32' 54"}
MOON_DIST:        81.49 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:      257.22,-41.09 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       48.86,-70.82 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220909286/quicklook/glg_lc_medres34_bn220909286.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 146.85,-24.90 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 09 Sep 22 06:52:52 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     684399138
GRB_RA:          222.717d {+14h 50m 52s} (J2000),
                 223.038d {+14h 52m 09s} (current),
                 222.011d {+14h 48m 03s} (1950)
GRB_DEC:         -19.300d {-19d 18' 00"} (J2000),
                 -19.393d {-19d 23' 32"} (current),
                 -19.094d {-19d 05' 38"} (1950)
GRB_ERROR:       11.98 [deg radius, statistical plus systematic]
GRB_INTEN:       240 [cnts/sec]
DATA_SIGNIF:     10.60 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        19831 TJD;   252 DOY;   22/09/09
GRB_TIME:        24733.82 SOD {06:52:13.82} UT
GRB_PHI:          68.00 [deg]
GRB_THETA:        55.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.52
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       1,0,1, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       167.66d {+11h 10m 38s}   +5.29d {+05d 17' 33"}
SUN_DIST:         59.80 [deg]   Sun_angle= -3.7 [hr] (East of Sun)
MOON_POSTN:      335.05d {+22h 20m 12s}  -15.55d {-15d 32' 52"}
MOON_DIST:       104.57 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:      338.08, 35.29 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      226.03, -2.78 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220909286/quicklook/glg_lc_medres34_bn220909286.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 146.85,-24.90 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 09 Sep 22 06:53:00 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     684399138
GRB_RA:          216.880d {+14h 27m 31s} (J2000),
                 217.205d {+14h 28m 49s} (current),
                 216.165d {+14h 24m 40s} (1950)
GRB_DEC:         -24.250d {-24d 15' 00"} (J2000),
                 -24.351d {-24d 21' 02"} (current),
                 -24.026d {-24d 01' 34"} (1950)
GRB_ERROR:       6.40 [deg radius, statistical only]
DATA_SIGNIF:     11.80 [sigma]
DATA_INTERVAL:   1.024 [sec]
GRB_DATE:        19831 TJD;   252 DOY;   22/09/09
GRB_TIME:        24733.82 SOD {06:52:13.82} UT
GRB_PHI:          63.00 [deg]
GRB_THETA:        61.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       167.66d {+11h 10m 38s}   +5.29d {+05d 17' 33"}
SUN_DIST:         56.59 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      335.05d {+22h 20m 12s}  -15.55d {-15d 32' 50"}
MOON_DIST:       107.42 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:      329.41, 33.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      222.38, -9.16 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220909286/quicklook/glg_lc_medres34_bn220909286.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_684399138.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 09 Sep 22 07:01:30 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     684399138
GRB_RA:          212.350d {+14h 09m 24s} (J2000),
                 212.662d {+14h 10m 39s} (current),
                 211.663d {+14h 06m 39s} (1950)
GRB_DEC:         -17.710d {-17d 42' 35"} (J2000),
                 -17.817d {-17d 48' 58"} (current),
                 -17.474d {-17d 28' 25"} (1950)
GRB_ERROR:       6.34 [deg radius, statistical only]
GRB_DATE:        19831 TJD;   252 DOY;   22/09/09
GRB_TIME:        24733.82 SOD {06:52:13.82} UT
GRB_PHI:          56.00 [deg]
GRB_THETA:        56.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       167.66d {+11h 10m 39s}   +5.29d {+05d 17' 25"}
SUN_DIST:         50.05 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:      335.13d {+22h 20m 32s}  -15.51d {-15d 30' 51"}
MOON_DIST:       114.25 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:      327.98, 41.34 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      216.19, -4.38 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220909286/quicklook/glg_lc_medres34_bn220909286.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220909286/quicklook/glg_locplot_all_bn220909286.png
COMMENTS:        Fermi-GBM Final Position.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file should be available by the time this FINAL notice is produced.  
COMMENTS:        This notice was generated completely by automated pipeline processing.  
COMMENTS:        This is likely a Long GRB.

GCN Circular #32539
The Fermi GBM team reports the detection of a likely LONG GRB
At 06:52:13 UT on 9 Sep 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220909A (trigger 684399138.822486 / 220909286).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 212.4, Dec = -17.7 (J2000 degrees, equivalent to J2000 14h 09m, -17d 41'), with a statistical uncertainty of 6.3 degrees.
The angle from the Fermi LAT boresight is 56.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220909286/quicklook/glg_skymap_all_bn220909286.png
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220909286/quicklook/glg_healpix_all_bn220909286.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220909286/quicklook/glg_lc_medres34_bn220909286.gif
GCN Circular #32543
Gayathri Raman (PSU), James DeLaunay (UAlabama), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), report:
Swift/BAT did not localize GRB 220909A onboard (T0: 2022-09-09T06:52:13 UTC, Fermi/GBM GCN 32539).
The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1).
Upon trigger, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.
The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu, arXiv:2111.01769), detects the burst with a sqrt(TS) of 8.9 in a 4.096 s analysis time bin.
NITRATES results, independently, are ambiguous with respect to whether this burst originates from in or outside the BAT FOV, with a borderline DeltaLLHOut of 6.7 and a marginally preferred arcminute location with DeltaLLHPeak of 2.
See Section 9.1 and Figure 20 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.
The BAT candidate position is RA, Dec = 216.0448, -8.8551 deg which is
```
   RA(J2000)  = 14h 24m 10.75s
   Dec(J2000) = -8d 51′ 18.4″
```
with an estimated uncertainty of 3 arcmin.
This position is consistent with the Fermi/GBM localization (GCN 32539). Independent spectral and/or fluence measurements of this burst from other instruments could help determine the preferred spatial origin.
XRT and UVOT follow-up has been requested. Results of follow-up observations will be reported in future circulars.
GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
GCN Circular #32544
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Swift/BAT-GUANO GRB 220909A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021513
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 Swift/BAT-GUANO 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 Circular #32547
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), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the Swift/BAT-GUANO-detected burst GRB 220909A, collecting 5.5 ks of Photon Counting (PC) mode data between T0+216.5 ks and T0+235.1 ks.
One uncatalogued X-ray source has been detected consistent with being within 296 arcsec of the Swift/BAT-GUANO position (Raman et al, GCN Circ. 32543), it is below the RASS limit and shows no definitive signs of fading. Therefore, at the present time we cannot confirm this as the afterglow. Details of this source are given below:
Source 5:
```
  RA (J2000.0):  216.0407  =  14:24:9.76
  Dec (J2000.0): -8.8439  =  -08:50:37.9
  Error: 7.3 arcsec (radius, 90% conf.)
  Count-rate: (1.12 [+0.72, -0.53])e-3 ct s^-1	 
  Distance: 43 arcsec from Swift/BAT-GUANO position.
```
Seven uncatalogued sources were also detected too far from the GRB position to be likely afterglow candidates.
The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00021513.
This circular is an official product of the Swift-XRT team.
GCN Circular #32556
C. Malacaria (ISSI) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 06:52:13.82 UT on 9 September 2022, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 220909A (trigger 684399138 / 220909286), which was also detected by Swift/GUANO (Raman et al. 2022, GCN 32543). The Fermi GBM Final Real-time Localization (GCN 32539) is consistent with the Swift-BAT GUANO position.
The angle from the Fermi LAT boresight at the GBM trigger time is 46 degrees.
The GBM light curve shows a peak with a duration (T90) of about 14.6 s (50-300 keV). The time-averaged spectrum from T0-1.5 s to T0+6.7 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.8 +/- 0.2 and the cutoff energy, parameterized as Epeak, is 154 +/- 25 keV.
The event fluence (10-1000 keV) in this time interval is (1.4 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+2.69 s in the 10-1000 keV band is 3.6 +/- 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/"

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Jochen Greiner, last update: 14-Sep-2022 [Disclaimer]