Gamma-ray Burst 200903A

(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:     Thu 03 Sep 20 00:56:55 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     994389,   Seg_Num: 0
GRB_RA:          164.311d {+10h 57m 15s} (J2000),
                 164.613d {+10h 58m 27s} (current),
                 163.577d {+10h 54m 18s} (1950)
GRB_DEC:         +50.501d {+50d 30' 02"} (J2000),
                 +50.390d {+50d 23' 23"} (current),
                 +50.768d {+50d 46' 05"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5081 [cnts]    Image_Peak=573 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       20876 [cnts]
BKG_TIME:        2646.43 SOD {00:44:06.43} UT
BKG_DUR:         8 [sec]
GRB_DATE:        19095 TJD;   247 DOY;   20/09/03
GRB_TIME:        2662.43 SOD {00:44:22.43} UT
GRB_PHI:         -45.30 [deg]
GRB_THETA:        26.79 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     43.72 [sigma]
IMAGE_SIGNIF:    17.74 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +5 -100  +0 -73  +0 
SUN_POSTN:       162.47d {+10h 49m 52s}   +7.44d {+07d 26' 24"}
SUN_DIST:         42.99 [deg]   Sun_angle= -0.1 [hr] (East of Sun)
MOON_POSTN:      352.92d {+23h 31m 41s}   -8.46d {-08d 27' 49"}
MOON_DIST:       137.51 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      158.07, 58.12 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      142.80, 39.76 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
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 = 261.61,16.81 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(3.0<100sec) coincident with the FERMI_GBM event (trignum=620786664).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 03 Sep 20 00:44:43 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     620786664
GRB_RA:          172.983d {+11h 31m 56s} (J2000),
                 173.259d {+11h 33m 02s} (current),
                 172.313d {+11h 29m 15s} (1950)
GRB_DEC:         +39.450d {+39d 27' 00"} (J2000),
                 +39.336d {+39d 20' 09"} (current),
                 +39.726d {+39d 43' 34"} (1950)
GRB_ERROR:       13.47 [deg radius, statistical plus systematic]
GRB_INTEN:       202 [cnts/sec]
DATA_SIGNIF:     8.80 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        19095 TJD;   247 DOY;   20/09/03
GRB_TIME:        2659.25 SOD {00:44:19.25} UT
GRB_PHI:           0.00 [deg]
GRB_THETA:        70.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.00
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:     100%  Below horizon
2nd_MOST_LIKELY:   0%  n/a
DETECTORS:       0,1,0, 1,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       162.46d {+10h 49m 50s}   +7.44d {+07d 26' 35"}
SUN_DIST:         33.34 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      352.83d {+23h 31m 18s}   -8.50d {-08d 30' 13"}
MOON_DIST:       149.17 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      171.17, 69.39 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      156.12, 33.06 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200903031/quicklook/glg_lc_medres34_bn200903031.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 344.87,19.10 [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 03 Sep 20 00:44:55 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      59
TRIGGER_NUM:     620786664
GRB_RA:          155.400d {+10h 21m 36s} (J2000),
                 155.729d {+10h 22m 55s} (current),
                 154.600d {+10h 18m 24s} (1950)
GRB_DEC:         +53.400d {+53d 23' 60"} (J2000),
                 +53.295d {+53d 17' 43"} (current),
                 +53.652d {+53d 39' 08"} (1950)
GRB_ERROR:       11.70 [deg radius, statistical plus systematic]
GRB_INTEN:       157 [cnts/sec]
DATA_SIGNIF:     13.70 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        19095 TJD;   247 DOY;   20/09/03
GRB_TIME:        2659.25 SOD {00:44:19.25} UT
GRB_PHI:         343.00 [deg]
GRB_THETA:        60.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      1.21
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      93%  GRB
2nd_MOST_LIKELY:   4%  Solar Flare
DETECTORS:       0,1,0, 1,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       162.46d {+10h 49m 50s}   +7.44d {+07d 26' 35"}
SUN_DIST:         46.18 [deg]   Sun_angle= 0.4 [hr] (West of Sun)
MOON_POSTN:      352.83d {+23h 31m 19s}   -8.50d {-08d 30' 11"}
MOON_DIST:       133.12 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      158.95, 51.93 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      134.74, 39.63 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200903031/quicklook/glg_lc_medres34_bn200903031.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 344.87,19.10 [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 03 Sep 20 00:53:48 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     620786664
GRB_RA:          159.040d {+10h 36m 10s} (J2000),
                 159.363d {+10h 37m 27s} (current),
                 158.255d {+10h 33m 01s} (1950)
GRB_DEC:         +54.910d {+54d 54' 36"} (J2000),
                 +54.802d {+54d 48' 09"} (current),
                 +55.169d {+55d 10' 09"} (1950)
GRB_ERROR:       3.56 [deg radius, statistical only]
GRB_DATE:        19095 TJD;   247 DOY;   20/09/03
GRB_TIME:        2659.25 SOD {00:44:19.25} UT
GRB_PHI:         345.00 [deg]
GRB_THETA:        58.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       162.46d {+10h 49m 51s}   +7.44d {+07d 26' 27"}
SUN_DIST:         47.43 [deg]   Sun_angle= 0.2 [hr] (West of Sun)
MOON_POSTN:      352.90d {+23h 31m 35s}   -8.47d {-08d 28' 26"}
MOON_DIST:       132.43 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      155.01, 52.95 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      136.24, 41.98 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200903031/quicklook/glg_lc_medres34_bn200903031.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200903031/quicklook/glg_locplot_all_bn200903031.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:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the CALET_GBM event (trignum=1283129005).

GCN NOTICE

 
TITLE:           GCN/SWIFT NOTICE 
NOTICE_DATE:     Thu 03 Sep 20 00:57:26 UT 
NOTICE_TYPE:     Swift-BAT GRB Lightcurve 
TRIGGER_NUM:     994389,   Seg_Num: 0 
GRB_RA:          164.311d {+10h 57m 15s} (J2000), 
                 164.613d {+10h 58m 27s} (current), 
                 163.577d {+10h 54m 18s} (1950) 
GRB_DEC:         +50.501d {+50d 30' 02"} (J2000), 
                 +50.390d {+50d 23' 23"} (current), 
                 +50.768d {+50d 46' 05"} (1950) 
GRB_DATE:        19095 TJD;   247 DOY;   20/09/03 
GRB_TIME:        2662.43 SOD {00:44:22.43} UT 
TRIGGER_INDEX:   146 
GRB_PHI:         -45.30 [deg] 
GRB_THETA:        26.79 [deg] 
DELTA_TIME:      0.00 [sec] 
TRIGGER_DUR:     1.024 [sec]  
SOLN_STATUS:     0x3 
RATE_SIGNIF:     43.72 [sigma] 
IMAGE_SIGNIF:    17.74 [sigma] 
LC_URL:          sw00994389000msb.lc 
SUN_POSTN:       162.47d {+10h 49m 52s}   +7.44d {+07d 26' 24"} 
SUN_DIST:         42.99 [deg]   Sun_angle= -0.1 [hr] (East of Sun) 
MOON_POSTN:      352.93d {+23h 31m 42s}   -8.46d {-08d 27' 42"} 
MOON_DIST:       137.51 [deg] 
MOON_ILLUM:      99 [%] 
GAL_COORDS:      158.07, 58.12 [deg] galactic lon,lat of the burst (or transient) 
ECL_COORDS:      142.80, 39.76 [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 = 261.61,16.81 [deg].

GCN Circular #28349
The Fermi GBM team reports the detection of a likely LONG GRB
At 00:44:19 UT on 3 Sep 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and loca\ ted GRB 200903A (trigger 620786664.250206 / 200903031).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 159.0, Dec \ = 54.9 (J2000 degrees, equivalent to J2000 10h 35m, 54d 53'), with a statistical uncerta\ inty of 3.6 degrees.
The angle from the Fermi LAT boresight is 58.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200903031/quicklook/glg\ _skymap_all_bn200903031.png
The HEALPix FITS file, including the estimated localization systematic, can be found her\ e: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200903031/quicklook/glg\ _healpix_all_bn200903031.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200903031/quicklook/glg\ _lc_medres34_bn200903031.gif
GCN Circular #28350
A. P. Beardmore (U Leicester), J.D. Gropp (PSU), A. Y. Lien (GSFC/UMBC), M. J. Moss (GWU), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team:
At 00:44:22 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200903A (trigger=994389). Swift did not slew immediately due to an observing constraint. The BAT on-board calculated location is RA, Dec 164.311, +50.501 which is
```
   RA(J2000) = 10h 57m 15s
   Dec(J2000) = +50d 30' 02"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 30 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to a Sun observing constraint, Swift cannot slew to the BAT position until 14:33 UT on 2020 September 12. There will thus be no XRT or UVOT data for this trigger before this time.
Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). 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 #28351
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (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, O.Ershova (Irkutsk State University, API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University)
MASTER-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB200903.03 (trigger No 994389,10h 57m 14.64s , +50d 30m 03.6s, R=0.05) errorbox 33 sec after notice time and 788 sec after trigger time at 2020-09-03 00:57:31 UT, with upper limit up to 14.0 mag. The observations began at zenith distance = 77 deg. The sun altitude is -22.2 deg.
The galactic latitude b = 59 deg., longitude l = 158 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1432852
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

     869 |      MASTER-Tavrida |   C |   160 | 14.0 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #28357
Y. Shimizu (Kanagawa U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration:
The long soft GRB 200903A (Swift detection: Beardmore et al., GCN Circ. 28350; https://gcn.gsfc.nasa.gov/other/200903A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 00:44:17.477 UTC on 3 September 2020 (http://cgbm.calet.jp/cgbm_trigger/flight/1283129005/). The burst signal was seen by all CGBM detectors.
The burst light curve shows a multi-peaked structure which starts at T+1.5 sec, peaks at T+5.9 sec, and ends at T+10.5 sec. The T90 and T50 durations measured by the SGM data are 8.2 +- 0.8 sec and 4.2 +- 0.8 sec (40-1000 keV), respectively.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1283129005/
The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN Circular #28360
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), 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 200903A (trigger #994389) (Beardmore et al., GCN Circ. 28350). The BAT ground-calculated position is RA, Dec = 164.313, 50.488 deg which is
```
   RA(J2000)  =  10h 57m 15.1s
   Dec(J2000) = +50d 29' 15.7"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 67%.
The mask-weighted light curve shows a precursor at ~T-19 s, followed by the main structure with several overlapping pulses that starts at ~T-5 s and ends at ~T+20 s. The burst went out of the BAT FOV at T+64 s. T90 (15-350 keV) is 24.15 +- 7.68 sec (estimated error including systematics).
The time-averaged spectrum from T-19.18 to T+22.13 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.15 +- 0.28, and Epeak of 107.4 +- 65.8 keV (chi squared 45.20 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 2.8 +- 0.1 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+0.14 sec in the 15-150 keV band is 3.8 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.56 +- 0.07 (chi squared 51.88 for 57 d.o.f.). 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/994389/BA/
GCN Circular #28362
S. Lesage (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 00:44:19.25 UT on 3 September 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200903A (trigger 620786664 / 200903031) which was also detected by the Swift/BAT (A. P. Beardmore et al. 2020, GCN 28350). The Fermi GBM Final Real-time Localization (GCN 28349) is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is ~61 degrees.
The GBM light curve shows a single bright peak with a duration (T90) of about 26.9 s (50-300 keV). The time-averaged spectrum from T0-5.4 s to T0+21.5 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.9 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 111.4 +/- 8.9 keV.
The event fluence (10-1000 keV) in this time interval is (4.6 +/- 0.2)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+3.3 s in the 10-1000 keV band is 6.03 +/- 0.24 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: 04-Sep-2020 [Disclaimer]