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GRB 210518A

GCN Circular 30045

Subject

GRB 210518A: Fermi GBM Final Real-time Localization

Date

2021-05-18T13:15:25Z (4 years ago)

From

Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 13:04:09 UT on 18 May 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210518A (trigger 643035854.639946 / 210518545).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 270.0, Dec = 49.6 (J2000 degrees, equivalent to J2000 18h 00m, 49d 36'), with a statistical uncertainty of 1.8 degrees.

The angle from the Fermi LAT boresight is 142.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210518545/quicklook/glg_skymap_all_bn210518545.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210518545/quicklook/glg_healpix_all_bn210518545.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210518545/quicklook/glg_lc_medres34_bn210518545.gif

GCN Circular 30049

Subject

Fermi GRB 210518A: Global MASTER-Net observations report

Date

2021-05-18T19:41:21Z (4 years ago)

From

Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

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) started inspect of the Fermi GRB 210518A ( Fermi GBM team, GCN 30045Loading...
 
 ) errorbox  21119 sec after notice time and 21211 sec after trigger time at 2021-05-18 18:57:41 UT, with upper limit up to  17.5 mag. Observations started at twilight.  The observations began at zenith distance = 48 deg. The sun  altitude  is -16.4 deg. 

MASTER-Kislovodsk robotic telescope  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 210518A errorbox  22517 sec after notice time and 22609 sec after trigger time at 2021-05-18 19:20:59 UT, with upper limit up to  18.9 mag. The observations began at zenith distance = 44 deg. The sun  altitude  is -22.7 deg. 

The galactic latitude b = 28 deg., longitude l = 77 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1615984

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   21242 | 2021-05-18 18:57:41 |      MASTER-Tavrida | (17h 48m 41.51s , +49d 49m 53.4s) |   C |    60 | 14.3 |        
   21321 | 2021-05-18 18:59:00 |      MASTER-Tavrida | (17h 44m 23.63s , +51d 42m 07.4s) |   C |    60 | 17.0 |        
   21401 | 2021-05-18 19:00:20 |      MASTER-Tavrida | (17h 57m 38.57s , +51d 41m 50.7s) |   C |    60 | 17.5 |        
   21482 | 2021-05-18 19:01:41 |      MASTER-Tavrida | (17h 59m 42.95s , +45d 59m 33.9s) |   C |    60 | 17.1 |        
   22181 | 2021-05-18 19:13:20 |      MASTER-Tavrida | (17h 42m 50.03s , +47d 56m 08.8s) |   C |    60 | 16.6 |        
   22260 | 2021-05-18 19:14:40 |      MASTER-Tavrida | (18h 01m 23.46s , +49d 48m 32.6s) |   C |    60 | 16.0 |        
   22340 | 2021-05-18 19:15:59 |      MASTER-Tavrida | (17h 53m 46.00s , +47d 53m 44.4s) |   C |    60 | 15.3 |        
   22419 | 2021-05-18 19:17:19 |      MASTER-Tavrida | (18h 05m 59.67s , +47d 53m 29.1s) |   C |    60 | 17.0 |        
   22499 | 2021-05-18 19:18:38 |      MASTER-Tavrida | (17h 48m 41.80s , +49d 49m 37.4s) |   C |    60 | 15.4 |        
   22578 | 2021-05-18 19:19:57 |      MASTER-Tavrida | (17h 44m 22.63s , +51d 42m 38.2s) |   C |    60 | 15.7 |        
   22640 | 2021-05-18 19:20:59 |   MASTER-Kislovodsk | (18h 21m 01.98s , +50d 40m 53.5s) |   C |    60 | 18.0 |        
   22720 | 2021-05-18 19:22:19 |   MASTER-Kislovodsk | (17h 45m 12.19s , +46d 54m 06.1s) |   C |    60 | 18.1 |        
   22720 | 2021-05-18 19:22:19 |   MASTER-Kislovodsk | (17h 51m 09.20s , +46d 29m 59.0s) |   C |    60 | 18.9 |        
   22737 | 2021-05-18 19:22:37 |      MASTER-Tavrida | (17h 59m 37.58s , +46d 00m 28.9s) |   C |    60 | 14.3 |        
   22960 | 2021-05-18 19:26:20 |   MASTER-Kislovodsk | (17h 39m 32.63s , +50d 19m 41.6s) |   C |    60 | 18.9 |        
   23252 | 2021-05-18 19:31:11 |      MASTER-Tavrida | (17h 42m 55.70s , +47d 55m 10.9s) |   C |    60 | 16.3 |        
   23331 | 2021-05-18 19:32:30 |      MASTER-Tavrida | (18h 01m 17.16s , +49d 47m 37.3s) |   C |    60 | 16.2 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.

GCN Circular 30053

Subject

IPN triangulation of GRB 210518A

Date

2021-05-19T19:18:30Z (4 years ago)

From

Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

I. G. Mitrofanov, D. V. Golovin, A. S. Kozyrev, M. L. Litvak,
and A. B. Sanin, on behalf of the HEND-Odyssey GRB team,

A. Ridnaia, S. Golenetskii, D. Frederiks, D. Svinkin,
A. Lysenko, and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team,

and

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr,
on behalf of the GRS-Odyssey GRB team, report:

The long-duration GRB 210518A
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 30045Loading...
 
 )
was detected by Fermi (GBM trigger 643035854), Konus-Wind,
and Mars-Odyssey (HEND) at about 47050 s UT (13:04:10).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  271.081 (18h 04m 19s) +50.035 (+50d 02' 07")
 Corners:
  288.400 (19h 13m 36s) +51.036 (+51d 02' 11")
  287.357 (19h 09m 26s) +51.489 (+51d 29' 21")
  255.561 (17h 02m 15s) +46.119 (+46d 07' 07")
  256.707 (17h 06m 50s) +46.052 (+46d 03' 09")
 ---------------------------------------------
The error box area is 9.4 sq. deg, and its maximum
dimension is 22.0 deg (the minimum one is 26 arcmin).
The Sun distance was 96 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB210518_T47051/IPN

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.