Gamma-ray Burst 200909B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 09 Sep 20 23:17:28 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     995288,   Seg_Num: 0
GRB_RA:          175.176d {+11h 40m 42s} (J2000),
                 175.435d {+11h 41m 44s} (current),
                 174.550d {+11h 38m 12s} (1950)
GRB_DEC:         -31.179d {-31d 10' 43"} (J2000),
                 -31.294d {-31d 17' 37"} (current),
                 -30.902d {-30d 54' 05"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       3107 [cnts]    Image_Peak=129 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   148     E_range: 25-100 keV
BKG_INTEN:       19605 [cnts]
BKG_TIME:        83814.39 SOD {23:16:54.39} UT
BKG_DUR:         8 [sec]
GRB_DATE:        19101 TJD;   253 DOY;   20/09/09
GRB_TIME:        83830.45 SOD {23:17:10.45} UT
GRB_PHI:         -48.19 [deg]
GRB_THETA:        37.53 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     13.15 [sigma]
IMAGE_SIGNIF:    7.51 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  -2 -100  +0 -80  +0 
SUN_POSTN:       168.71d {+11h 14m 50s}   +4.85d {+04d 51' 04"}
SUN_DIST:         36.71 [deg]   Sun_angle= -0.4 [hr] (East of Sun)
MOON_POSTN:       71.59d {+04h 46m 22s}  +21.33d {+21d 20' 03"}
MOON_DIST:       112.30 [deg]
MOON_ILLUM:      54 [%]
GAL_COORDS:      285.59, 29.30 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      189.32,-30.24 [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 = 109.86,-18.66 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 09 Sep 20 23:20:56 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     995288,   Seg_Num: 0
GRB_RA:          175.176d {+11h 40m 42s} (J2000),
                 175.435d {+11h 41m 44s} (current),
                 174.550d {+11h 38m 12s} (1950)
GRB_DEC:         -31.179d {-31d 10' 43"} (J2000),
                 -31.294d {-31d 17' 37"} (current),
                 -30.902d {-30d 54' 05"} (1950)
GRB_DATE:        19101 TJD;   253 DOY;   20/09/09
GRB_TIME:        83830.45 SOD {23:17:10.45} UT
TRIGGER_INDEX:   148
GRB_PHI:         -48.19 [deg]
GRB_THETA:        37.53 [deg]
DELTA_TIME:      -5.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     13.15 [sigma]
IMAGE_SIGNIF:    7.51 [sigma]
LC_URL:          sw00995288000msb.lc
SUN_POSTN:       168.71d {+11h 14m 50s}   +4.85d {+04d 51' 00"}
SUN_DIST:         36.71 [deg]   Sun_angle= -0.4 [hr] (East of Sun)
MOON_POSTN:       71.62d {+04h 46m 29s}  +21.34d {+21d 20' 26"}
MOON_DIST:       112.27 [deg]
MOON_ILLUM:      54 [%]
GAL_COORDS:      285.59, 29.30 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      189.32,-30.24 [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 = 109.86,-18.66 [deg].

GCN Circular #28406
A. Melandri (INAF-OAB), M. G. Bernardini (INAF-OAB), J. A. Kennea (PSU), N. J. Klingler (PSU), N. P. M. Kuin (UCL-MSSL), K. L. Page (U Leicester), D. M. Palmer (LANL) and T. Sbarrato (INAF-OAB) report on behalf of the Neil Gehrels Swift Observatory Team:
At 23:17:10 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200909B (trigger=995288). Swift did not slew to the location due to an observing constraint. The BAT on-board calculated location is RA, Dec 175.176, -31.179 which is
```
   RA(J2000) = 11h 40m 42s
   Dec(J2000) = -31d 10' 43"
```
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 ~1500 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 03:23 UT on 2020 November 09. There will thus be no XRT or UVOT data for this trigger before this time.
Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.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 #28407
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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB200909.97 (trigger No 995288,11h 40m 42.24s , -31d 10m 44.4s, R=0.05) errorbox 28 sec after notice time and 49 sec after trigger time at 2020-09-09 23:18:00 UT, with upper limit up to 15.9 mag. Observations started at twilight. The observations began at zenith distance = 79 deg. The sun altitude is -12.4 deg.
The galactic latitude b = 29 deg., longitude l = 286 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1437483
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

      55 |         MASTER-OAFA |   C |    10 | 15.0 |        
      84 |         MASTER-OAFA |   C |    10 | 15.0 |        
     122 |         MASTER-OAFA |   C |    20 | 15.3 |        
     166 |         MASTER-OAFA |   C |    30 | 15.5 |        
     220 |         MASTER-OAFA |   C |    40 | 15.7 |        
     285 |         MASTER-OAFA |   C |    50 | 15.9 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #28408
S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), A. Melandri (INAF-OAB), 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-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 200909B (trigger #995288) (Melandri, et al., GCN Circ. 28406). The BAT ground-calculated position is RA, Dec = 175.171, -31.199 deg which is
```
    RA(J2000)  =  11h 40m 41.1s
    Dec(J2000) = -31d 11' 54.7"
```
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%.
The mask-weighted light curve shows a single peak that stars at T-6 sec, peaks at T+1 sec, and ends at T+20 sec. A hint of an extended emission is visible until T+40 sec. T90 (15-350 keV) is 16.9 +- 2.2 sec (estimated error including systematics).
The time-averaged spectrum from T-5.6 to T+14.2 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.60 +- 0.14. The fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.44 sec in the 15-150 keV band is 1.3 +- 0.3 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/995288/BA/

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Jochen Greiner, last update: 15-Oct-2020 [Disclaimer]