Gamma-ray Burst 200919A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 19 Sep 20 01:53:04 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     996503,   Seg_Num: 0
GRB_RA:          168.916d {+11h 15m 40s} (J2000),
                 169.195d {+11h 16m 47s} (current),
                 168.240d {+11h 12m 58s} (1950)
GRB_DEC:         +32.457d {+32d 27' 25"} (J2000),
                 +32.344d {+32d 20' 37"} (current),
                 +32.730d {+32d 43' 47"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       11834 [cnts]    Image_Peak=379 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   298     E_range: 25-100 keV
BKG_INTEN:       98883 [cnts]
BKG_TIME:        6686.34 SOD {01:51:26.34} UT
BKG_DUR:         40 [sec]
GRB_DATE:        19111 TJD;   263 DOY;   20/09/19
GRB_TIME:        6740.93 SOD {01:52:20.93} UT
GRB_PHI:         -120.97 [deg]
GRB_THETA:        25.26 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     14.45 [sigma]
IMAGE_SIGNIF:    9.51 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +2  +0 -100  +0 -84  +0 
SUN_POSTN:       176.88d {+11h 47m 30s}   +1.35d {+01d 21' 10"}
SUN_DIST:         31.82 [deg]   Sun_angle= 0.5 [hr] (West of Sun)
MOON_POSTN:      199.52d {+13h 18m 05s}   -3.34d {-03d 20' 19"}
MOON_DIST:        45.83 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      192.73, 68.60 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      156.37, 25.33 [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 = 127.69,18.89 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 19 Sep 20 01:56:32 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     996503,   Seg_Num: 0
GRB_RA:          168.916d {+11h 15m 40s} (J2000),
                 169.195d {+11h 16m 47s} (current),
                 168.240d {+11h 12m 58s} (1950)
GRB_DEC:         +32.457d {+32d 27' 25"} (J2000),
                 +32.344d {+32d 20' 37"} (current),
                 +32.730d {+32d 43' 47"} (1950)
GRB_DATE:        19111 TJD;   263 DOY;   20/09/19
GRB_TIME:        6740.93 SOD {01:52:20.93} UT
TRIGGER_INDEX:   298
GRB_PHI:         -120.97 [deg]
GRB_THETA:        25.26 [deg]
DELTA_TIME:      -18.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     14.45 [sigma]
IMAGE_SIGNIF:    9.51 [sigma]
LC_URL:          sw00996503000msb.lc
SUN_POSTN:       176.88d {+11h 47m 31s}   +1.35d {+01d 21' 06"}
SUN_DIST:         31.83 [deg]   Sun_angle= 0.5 [hr] (West of Sun)
MOON_POSTN:      199.55d {+13h 18m 13s}   -3.35d {-03d 21' 13"}
MOON_DIST:        45.86 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      192.73, 68.60 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      156.37, 25.33 [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 = 127.69,18.89 [deg].

GCN Circular #28454
T. N. Ukwatta (LANL), D. N. Burrows (PSU), V. D'Elia (SSDC), S. Laha (GSFC/UMBC/CRESST), D. M. Palmer (LANL), B. Sbarufatti (PSU) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team:
At 01:52:20 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200919A (trigger=996503). Swift did not slew due to an observing constraint. The BAT on-board calculated location is RA, Dec 168.916, +32.457 which is
```
   RA(J2000) = 11h 15m 40s
   Dec(J2000) = +32d 27' 25"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single complex peak structure with a duration of about 40 sec. The peak count rate was ~1600 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 05:40 UT on 2020 October 10. There will thus be no XRT or UVOT data for this trigger before this time.
Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). 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 #28455
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 GRB200919.08 (trigger No 996503,11h 15m 39.84s , +32d 27m 25.2s, R=0.05) errorbox 15 sec after notice time and 83 sec after trigger time at 2020-09-19 01:53:44 UT, with upper limit up to 17.1 mag. The observations began at zenith distance = 79 deg. The sun altitude is -17.1 deg.
The galactic latitude b = 69 deg., longitude l = 193 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1444350
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

      93 |      MASTER-Tavrida |   C |    20 | 16.3 |        
     118 |      MASTER-Tavrida |   C |    70 | 16.9 |  Coadd 
     134 |      MASTER-Tavrida |   C |    20 | 16.3 |        
     179 |      MASTER-Tavrida |   C |    30 | 16.3 |        
     235 |      MASTER-Tavrida |   C |    40 | 16.8 |        
     300 |      MASTER-Tavrida |   C |    50 | 16.9 |        
     381 |      MASTER-Tavrida |   C |    70 | 17.1 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #28458
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 200919A (trigger #996503) (Ukwatta et al., GCN Circ. 28454). The BAT ground-calculated position is RA, Dec = 168.899, 32.456 deg which is
```
   RA(J2000)  =  11h 15m 35.7s
   Dec(J2000) = +32d 27' 21.8"
```
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 62%.
The mask-weighted light curve shows several overlapping pulses that start at ~T-60 s and end at ~T+25 s. The main peak occurs at ~T+5 s. T90 (15-350 keV) is 76.0 +- 6.9 sec (estimated error including systematics).
The time-averaged spectrum from T-61.47 to T+24.54 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.13 +- 0.14. The fluence in the 15-150 keV band is 1.8 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+4.30 sec in the 15-150 keV band is 1.2 +- 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/996503/BA/
GCN Circular #28460
S. Belkin (IKI), V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of IKI-GRB-FuN:
We observed the GRB 200919A (Ukwatta et al., GCN 28454) with ZTSH 2.6m telescope of CrAO observatory starting on 2020-09-19 (UT) 02:26:25. We do not detect any new evident object in the BAT GRB 200919A localization field (Ukwatta et al., GCN 28454). Preliminary photometry of the field is following
```
Date       UT start  t-T0    Filter Exp.   OT    Err. UL
                     (mid, days)     (s)
2020-09-19 02:26:25  0.02541 R      30*10  n/d   n/d 19.8
```
The photometry is based on nearby USNO-B1.0 stars
```
USNO-B1.0_id R2
1224-0243383 15.75
1224-0243414 15.12
```

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Jochen Greiner, last update: 19-Sep-2020 [Disclaimer]