Gamma-ray Burst 191031A

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 31 Oct 19 00:37:07 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     932435,   Seg_Num: 0
GRB_RA:          233.470d {+15h 33m 53s} (J2000),
                 233.715d {+15h 34m 52s} (current),
                 232.854d {+15h 31m 25s} (1950)
GRB_DEC:          +6.144d {+06d 08' 37"} (J2000),
                  +6.078d {+06d 04' 41"} (current),
                  +6.311d {+06d 18' 38"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5538 [cnts]    Image_Peak=175 [image_cnts]
TRIGGER_DUR:     2.048 [sec] 
TRIGGER_INDEX:   264     E_range: 25-100 keV
BKG_INTEN:       53853 [cnts]
BKG_TIME:        2160.16 SOD {00:36:00.16} UT
BKG_DUR:         24 [sec]
GRB_DATE:        18787 TJD;   304 DOY;   19/10/31
GRB_TIME:        2193.69 SOD {00:36:33.69} UT
GRB_PHI:         -99.83 [deg]
GRB_THETA:        26.36 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     12.48 [sigma]
IMAGE_SIGNIF:    7.26 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +2  -3 -100  +0 -88  +0 
SUN_POSTN:       214.95d {+14h 19m 47s}  -13.95d {-13d 56' 43"}
SUN_DIST:         27.35 [deg]   Sun_angle= -1.3 [hr] (East of Sun)
MOON_POSTN:      254.38d {+16h 57m 31s}  -20.50d {-20d 30' 14"}
MOON_DIST:        33.45 [deg]
MOON_ILLUM:      11 [%]
GAL_COORDS:       11.89, 46.10 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      229.40, 24.58 [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:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 211.75,18.37 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(2.0<100sec) coincident with the FERMI_GBM event (trignum=594175000).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 31 Oct 19 00:37:00 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     594175000
GRB_RA:          247.100d {+16h 28m 24s} (J2000),
                 247.348d {+16h 29m 24s} (current),
                 246.475d {+16h 25m 54s} (1950)
GRB_DEC:          +3.333d {+03d 19' 60"} (J2000),
                  +3.291d {+03d 17' 26"} (current),
                  +3.443d {+03d 26' 35"} (1950)
GRB_ERROR:       28.22 [deg radius, statistical plus systematic]
GRB_INTEN:       69 [cnts/sec]
DATA_SIGNIF:     5.90 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        18787 TJD;   304 DOY;   19/10/31
GRB_TIME:        2195.61 SOD {00:36:35.61} UT
GRB_PHI:         330.00 [deg]
GRB_THETA:        85.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.85
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      55%  GRB
2nd_MOST_LIKELY:  42%  Distant Particles
DETECTORS:       0,0,0, 0,1,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       214.95d {+14h 19m 47s}  -13.95d {-13d 56' 43"}
SUN_DIST:         36.46 [deg]   Sun_angle= -2.2 [hr] (East of Sun)
MOON_POSTN:      254.38d {+16h 57m 30s}  -20.50d {-20d 30' 13"}
MOON_DIST:        24.77 [deg]
MOON_ILLUM:      11 [%]
GAL_COORDS:       18.12, 33.07 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      244.67, 24.78 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031025/quicklook/glg_lc_medres34_bn191031025.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 287.55,24.53 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 31 Oct 19 00:37:16 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     594175000
GRB_RA:          242.050d {+16h 08m 12s} (J2000),
                 242.289d {+16h 09m 09s} (current),
                 241.449d {+16h 05m 48s} (1950)
GRB_DEC:          +9.050d {+09d 03' 00"} (J2000),
                  +8.998d {+08d 59' 54"} (current),
                  +9.182d {+09d 10' 54"} (1950)
GRB_ERROR:       13.70 [deg radius, statistical only]
DATA_SIGNIF:     6.50 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        18787 TJD;   304 DOY;   19/10/31
GRB_TIME:        2195.61 SOD {00:36:35.61} UT
GRB_PHI:         327.00 [deg]
GRB_THETA:        92.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       214.95d {+14h 19m 47s}  -13.95d {-13d 56' 43"}
SUN_DIST:         35.53 [deg]   Sun_angle= -1.8 [hr] (East of Sun)
MOON_POSTN:      254.38d {+16h 57m 31s}  -20.50d {-20d 30' 15"}
MOON_DIST:        31.81 [deg]
MOON_ILLUM:      11 [%]
GAL_COORDS:       21.27, 40.25 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      237.90, 29.43 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031025/quicklook/glg_lc_medres34_bn191031025.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_594175000.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.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the SWIFT_BAT event (trignum=932435).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 31 Oct 19 00:45:53 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     594175000
GRB_RA:          247.340d {+16h 29m 22s} (J2000),
                 247.553d {+16h 30m 13s} (current),
                 246.804d {+16h 27m 13s} (1950)
GRB_DEC:         +22.130d {+22d 07' 48"} (J2000),
                 +22.088d {+22d 05' 16"} (current),
                 +22.238d {+22d 14' 18"} (1950)
GRB_ERROR:       12.95 [deg radius, statistical only]
GRB_DATE:        18787 TJD;   304 DOY;   19/10/31
GRB_TIME:        2195.61 SOD {00:36:35.61} UT
GRB_PHI:         313.00 [deg]
GRB_THETA:        93.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       214.95d {+14h 19m 49s}  -13.95d {-13d 56' 50"}
SUN_DIST:         48.17 [deg]   Sun_angle= -2.2 [hr] (East of Sun)
MOON_POSTN:      254.47d {+16h 57m 52s}  -20.52d {-20d 31' 09"}
MOON_DIST:        43.14 [deg]
MOON_ILLUM:      11 [%]
GAL_COORDS:       39.73, 40.60 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      240.64, 43.29 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031025/quicklook/glg_lc_medres34_bn191031025.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031025/quicklook/glg_locplot_all_bn191031025.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.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the SWIFT_BAT event (trignum=932435).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 31 Oct 19 00:41:16 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     932435,   Seg_Num: 0
GRB_RA:          233.470d {+15h 33m 53s} (J2000),
                 233.715d {+15h 34m 52s} (current),
                 232.854d {+15h 31m 25s} (1950)
GRB_DEC:          +6.144d {+06d 08' 37"} (J2000),
                  +6.078d {+06d 04' 41"} (current),
                  +6.311d {+06d 18' 38"} (1950)
GRB_DATE:        18787 TJD;   304 DOY;   19/10/31
GRB_TIME:        2193.69 SOD {00:36:33.69} UT
TRIGGER_INDEX:   264
GRB_PHI:         -99.83 [deg]
GRB_THETA:        26.36 [deg]
DELTA_TIME:      6.00 [sec]
TRIGGER_DUR:     2.048 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     12.48 [sigma]
IMAGE_SIGNIF:    7.26 [sigma]
LC_URL:          sw00932435000msb.lc
SUN_POSTN:       214.95d {+14h 19m 48s}  -13.95d {-13d 56' 46"}
SUN_DIST:         27.35 [deg]   Sun_angle= -1.3 [hr] (East of Sun)
MOON_POSTN:      254.42d {+16h 57m 41s}  -20.51d {-20d 30' 40"}
MOON_DIST:        33.48 [deg]
MOON_ILLUM:      11 [%]
GAL_COORDS:       11.89, 46.10 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      229.40, 24.58 [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:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 211.75,18.37 [deg].

GCN Circular #26101
A. D'Ai (INAF-IASFPA), E. Ambrosi (INAF-IASFPA), V. D'Elia (SSDC), J. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), M. H. Siegel (PSU) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team:
At 00:36:33 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 191031A (trigger=932435). Swift did not slew due to an observing constraint. The BAT on-board calculated location is RA, Dec 233.470, +6.144 which is
```
   RA(J2000) = 15h 33m 53s
   Dec(J2000) = +06d 08' 37"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 50 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~2 sec after the trigger.
Due to a Sun observing constraint, Swift cannot slew to the BAT position until 23:18 UT on 2019 December 22. There will thus be no XRT or UVOT data for this trigger before this time.
Burst Advocate for this burst is A. D'Ai (antonino.dai 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 #26102
The Fermi GBM team reports the detection of a likely LONG GRB
At 00:36:35 UT on 31 Oct 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191031A (trigger 594175000.608294 / 191031025).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 247.3, Dec = 22.1 (J2000 degrees, equivalent to J2000 16h 29m, 22d 06'), with a statistical uncertainty of 12.9 degrees.
The angle from the Fermi LAT boresight is 93.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031025/quicklook/glg_skymap_all_bn191031025.png
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031025/quicklook/glg_healpix_all_bn191031025.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031025/quicklook/glg_lc_medres34_bn191031025.gif
GCN Circular #26103
Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Diego González (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Margarita Pereyra (UNAM), and Eleonora Troja (GSFC) report:
We observed the field of GRB 191031A (D'Ai et al., GCN Circ. 26101; Fermi GBM Team, GCN Circ. 26102) with the COATLI 50-cm telescope and interim imager at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir (http://coatli.astroscu.unam.mx) from 2019-10-31 02:14 UTC (1.63 hours after the trigger) to 02:25, obtaining a total of 540 seconds of exposure in the w filter. The observations were taken at airmasses between 6.4 and 8.3.
We do not detetect any uncataloged sources in the BAT error region to a 10-sigma limit of w = 18.75.
Our w magnitudes are calibrated against the Pan-STARRS1 catalog, are on an approximate AB system (Becerra et al., 2019, ApJ, 872, 118), and are not corrected for Galactic extinction in the direction of the GRB.
We thank the COATLI technical team and the staff of the Observatorio Astronómico Nacional.
GCN Circular #26116
S. Lesage (UAH), R. Hamburg (UAH), and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 00:36:35.61 UT on 31 October 2019, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 191031A (trigger 594175000 / 191031025) which was also detected by the Swift/BAT (D'Ai et al. 2019, GCN 26101) The Fermi GBM Final Real-time Localization (GCN 26102) is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 106 degrees.
The GBM light curve shows two pulses with a duration (T90) of about 200 s (50-300 keV). The time-averaged spectrum of the first pulse from T0-10.24 s to T0+10.24 s is best fit by a power law with an exponential high-energy cutoff. The power law index is -0.9 +/- 0.2 and the cutoff energy, parameterized as Epeak, is 218 +/- 57 keV. The time-averaged spectrum of the second pulse from T+174.08 to T0+197.64 is best fit by the same function with an index of -1.1 +/- 0.1 and an Epeak of 242 +/- 48 keV.
The event fluence (10-1000 keV) in the time interval of the two pulses is (6.6 +/- 0.6)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+175.56 s in the 10-1000 keV band is 2.5 +/- 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 #26131
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), A. D'Ai (INAF-IASFPA), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-61 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 191031A (trigger #932435) (D'Ai, et al., GCN Circ. 26101). The BAT ground-calculated position is RA, Dec = 233.490, 6.109 deg which is
```
 RA(J2000)  =  15h 33m 57.7s 
 Dec(J2000) = +06d 06' 32.9" 
```
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 46%.
The mask-weighted light curve shows a single pulse with some overlying structure. The emission starts at ~T-8 sec, peaks at T+3 sec, and decays to background by ~T+18 sec. A pre-planned spacecraft slew took the burst location out of the field of view by T+95 sec. T90 (15-350 keV) is 19.1 +- 6.3 sec (estimated error including systematics).
The time-averaged spectrum from T-11.08 to T+16.87 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.38 +- 0.19. The fluence in the 15-150 keV band is 9.0 +- 1.1 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+3.48 sec in the 15-150 keV band is 1.0 +- 0.2 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/932435/BA/

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Jochen Greiner, last update: 01-Nov-2019 [Disclaimer]