Gamma-ray Burst 230707A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 07 Jul 23 03:23:21 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     710392976
GRB_RA:          178.017d {+11h 52m 04s} (J2000),
                 178.317d {+11h 53m 16s} (current),
                 177.380d {+11h 49m 31s} (1950)
GRB_DEC:         -18.117d {-18d 07' 00"} (J2000),
                 -18.248d {-18d 14' 50"} (current),
                 -17.839d {-17d 50' 18"} (1950)
GRB_ERROR:       7.88 [deg radius, statistical plus systematic]
GRB_INTEN:       244 [cnts/sec]
DATA_SIGNIF:     11.40 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        20132 TJD;   188 DOY;   23/07/07
GRB_TIME:        12171.96 SOD {03:22:51.96} UT
GRB_PHI:         269.00 [deg]
GRB_THETA:        70.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.68
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       0,0,0, 1,0,0, 0,1,0, 0,0,0, 0,0,
SUN_POSTN:       106.06d {+07h 04m 14s}  +22.61d {+22d 36' 52"}
SUN_DIST:         81.56 [deg]   Sun_angle= -4.8 [hr] (East of Sun)
MOON_POSTN:      339.31d {+22h 37m 15s}  -13.23d {-13d 13' 57"}
MOON_DIST:       143.36 [deg]
MOON_ILLUM:      81 [%]
GAL_COORDS:      283.64, 42.52 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      185.62,-17.36 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230707141/quicklook/glg_lc_medres34_bn230707141.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 99.85,7.03 [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 07 Jul 23 03:23:30 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     710392976
GRB_RA:          172.567d {+11h 30m 16s} (J2000),
                 172.862d {+11h 31m 27s} (current),
                 171.939d {+11h 27m 45s} (1950)
GRB_DEC:         -19.283d {-19d 16' 59"} (J2000),
                 -19.413d {-19d 24' 46"} (current),
                 -19.007d {-19d 00' 26"} (1950)
GRB_ERROR:       7.55 [deg radius, statistical plus systematic]
GRB_INTEN:       199 [cnts/sec]
DATA_SIGNIF:     19.10 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        20132 TJD;   188 DOY;   23/07/07
GRB_TIME:        12171.96 SOD {03:22:51.96} UT
GRB_PHI:         270.98 [deg]
GRB_THETA:        65.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.98
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic Transient
DETECTORS:       0,0,0, 1,0,0, 0,1,0, 0,0,0, 0,0,
SUN_POSTN:       106.06d {+07h 04m 14s}  +22.61d {+22d 36' 52"}
SUN_DIST:         77.58 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      339.31d {+22h 37m 15s}  -13.23d {-13d 13' 55"}
MOON_DIST:       144.73 [deg]
MOON_ILLUM:      81 [%]
GAL_COORDS:      277.79, 39.59 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      181.18,-20.58 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230707141/quicklook/glg_lc_medres34_bn230707141.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 99.85,7.03 [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 07 Jul 23 03:23:40 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     710392976
GRB_RA:          172.930d {+11h 31m 43s} (J2000),
                 173.226d {+11h 32m 54s} (current),
                 172.301d {+11h 29m 12s} (1950)
GRB_DEC:         -17.980d {-17d 58' 47"} (J2000),
                 -18.110d {-18d 06' 35"} (current),
                 -17.704d {-17d 42' 13"} (1950)
GRB_ERROR:       2.92 [deg radius, statistical only]
DATA_SIGNIF:     19.50 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        20132 TJD;   188 DOY;   23/07/07
GRB_TIME:        12171.96 SOD {03:22:51.96} UT
GRB_PHI:         272.00 [deg]
GRB_THETA:        66.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       106.06d {+07h 04m 14s}  +22.61d {+22d 36' 52"}
SUN_DIST:         77.24 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      339.32d {+22h 37m 16s}  -13.23d {-13d 13' 52"}
MOON_DIST:       145.79 [deg]
MOON_ILLUM:      81 [%]
GAL_COORDS:      277.52, 40.93 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      180.93,-19.26 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230707141/quicklook/glg_lc_medres34_bn230707141.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_710392976.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 07 Jul 23 03:33:08 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     710392976
GRB_RA:          173.910d {+11h 35m 38s} (J2000),
                 174.207d {+11h 36m 50s} (current),
                 173.279d {+11h 33m 07s} (1950)
GRB_DEC:         -17.100d {-17d 06' 00"} (J2000),
                 -17.230d {-17d 13' 48"} (current),
                 -16.823d {-16d 49' 23"} (1950)
GRB_ERROR:       2.52 [deg radius, statistical only]
GRB_DATE:        20132 TJD;   188 DOY;   23/07/07
GRB_TIME:        12171.96 SOD {03:22:51.96} UT
GRB_PHI:         272.00 [deg]
GRB_THETA:        67.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       106.07d {+07h 04m 16s}  +22.61d {+22d 36' 50"}
SUN_DIST:         77.62 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      339.41d {+22h 37m 37s}  -13.19d {-13d 11' 27"}
MOON_DIST:       146.25 [deg]
MOON_ILLUM:      81 [%]
GAL_COORDS:      278.20, 42.10 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      181.44,-18.07 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230707141/quicklook/glg_lc_medres34_bn230707141.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230707141/quicklook/glg_locplot_all_bn230707141.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 #34156
The Fermi GBM team reports the detection of a likely LONG GRB
At 03:22:51 UT on 7 Jul 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230707A (trigger 710392976.959644 / 230707141).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 173.9, Dec = -17.1 (J2000 degrees, equivalent to J2000 11h 35m, -17d 06'), with a statistical uncertainty of 2.5 degrees.
The angle from the Fermi LAT boresight is 67.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230707141/quicklook/glg_skymap_all_bn230707141.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/bn230707141/quicklook/glg_healpix_all_bn230707141.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230707141/quicklook/glg_lc_medres34_bn230707141.gif
GCN Circular #34157
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-OAGH robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 230707A ( Fermi GBM team, GCN 34156) errorbox 174 sec after notice time and 210 sec after trigger time at 2023-07-07 03:26:21 UT, with upper limit up to 18.0 mag. Observations started at twilight. The observations began at zenith distance = 71 deg. The sun altitude is -11.9 deg.
MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 230707A errorbox 804 sec after notice time and 840 sec after trigger time at 2023-07-07 03:36:52 UT, with upper limit up to 12.3 mag. The observations began at zenith distance = 87 deg. The sun altitude is -73.8 deg.
The galactic latitude b = 42 deg., longitude l = 279 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2234493
We obtain a following upper limits.
```
Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     230 | 2023-07-07 03:26:21 |         MASTER-OAGH | (11h 31m 43.96s , -18d 19m 29.8s) |   C |    40 | 16.8 |        
     451 | 2023-07-07 03:29:42 |         MASTER-OAGH | (11h 31m 38.19s , -18d 20m 47.6s) |   C |    80 | 17.2 |        
     916 | 2023-07-07 03:36:42 |         MASTER-OAGH | (11h 35m 36.07s , -17d 26m 31.7s) |   C |   170 | 17.8 |        
     906 | 2023-07-07 03:36:52 |         MASTER-OAFA | (11h 33m 57.32s , -16d 58m 43.3s) |   C |   130 | 12.3 |        
    1251 | 2023-07-07 03:42:12 |         MASTER-OAGH | (11h 35m 36.41s , -17d 28m 18.2s) |   C |   180 | 18.0 |        
    1592 | 2023-07-07 03:47:53 |         MASTER-OAGH | (11h 31m 07.26s , -16d 16m 23.9s) |   C |   180 | 17.7 |        
    1934 | 2023-07-07 03:53:35 |         MASTER-OAGH | (11h 39m 30.22s , -16d 16m 43.2s) |   C |   180 | 18.0 |        
    2274 | 2023-07-07 03:59:15 |         MASTER-OAGH | (11h 31m 16.26s , -16d 16m 40.2s) |   C |   180 | 17.7 |        
    2620 | 2023-07-07 04:05:01 |         MASTER-OAGH | (11h 39m 28.83s , -16d 16m 03.1s) |   C |   180 | 18.0 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #34159
Aaron Tohuvavohu (U Toronto), James DeLaunay (U Alabama), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:
Swift/BAT did not localize GRB 230707A onboard (T0: 2023-07-07T03:22:51 UTC, Fermi/GBM GCN 34156).
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 by this notice, 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 burst is ~15 s in duration as seen by BAT.
In ground analysis of the available data, we find the position of the burst with SNR 10.0 in the image domain. The BAT position is RA, Dec = 171.4759 -21.5125, which is:
```
    RA (J2000)     11h 25m 54.22s
    Dec (J2000)  -21d 30' 45.0"
```
with an estimated uncertainty of 2 arcminutes.
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 #34160
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Swift/BAT-GUANO GRB 230707A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021587
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 #34162
P. Veres and C. Meegan (both UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 03:22:51.96 UT on 07 July 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230707A (trigger 710392976/230707141), which was also detected by the Swift/BAT-GUANO (Tohuvavohu et al. 2023, GCN 34159). The Fermi GBM Final Real-time Localization (GCN 34156) is consistent with the Swift position. The angle from the Fermi LAT boresight is 63 degrees.
The GBM light curve consists of multiple pulses with a duration (T90) of about 29 s (50-300 keV). The time-averaged spectrum from T0-2.8 to T0+30.0 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.77 +/- 0.08 and the cutoff energy, parameterized as Epeak, is 121 +/- 7 keV.
The event fluence (10-1000 keV) in this time interval is (6.9 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.5 s in the 10-1000 keV band is 6.5 +/- 0.3 ph/s/cm^2.
A Band function fits the spectrum equally well with Epeak= 110 +/- 10 keV, alpha = -0.7 +/- 0.1 and beta = -2.5 +/- 0.2.
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 #34168
A. Tohuvavohu (U. Toronto), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), D.N. Burrows (PSU), J. D. Gropp (PSU) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the Swift/BAT-GUANO-detected burst GRB 230707A, collecting 4.7 ks of Photon Counting (PC) mode data between T0+32.7 ks and T0+51.0 ks.
No X-ray sources have been detected consistent with being within 197 arcsec of the Swift/BAT-GUANO position. The 3-sigma upper limit in the field ranges from ~0.002 to ~0.003 ct s^-1, corresponding to a 0.3-10 keV observed flux of 9.4e-14 to 1.3e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).
Three uncatalogued sources were 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/00021587.
This circular is an official product of the Swift-XRT team.
GCN Circular #34205
Aaron Tohuvavohu (U Toronto), Dmitry Svinkin (Ioffe Institute) report:
The prior reporting of the arcminute localization of GRB 230707A (GCN 34159) is incorrect.
The GRB signal detected and localized by BAT-GUANO is real, and correctly localized to arcminute precision in the instrument frame. However, an incorrect spacecraft attitude quaternion was used for conversion from instrument to celestial coordinates.
The corrected BAT position for this burst is: RA, Dec = 173.1992 -16.4121, which is:
```
    RA (J2000)     11h 32m 47.81s
    Dec (J2000)  -16d 24' 43.6"
```
with an estimated uncertainty of 2 arcminutes.
This position is 5.35 degrees from the position reported in GCN 34159. I apologize for the error, and gratefully acknowledge the critical support from IPN teammates in identifying this discrepancy.
The source of the error has been identified and corrections will be implemented. Previous BAT localizations have not been affected by this error.

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Jochen Greiner, last update: 02-Aug-2023 [Disclaimer]