Gamma-ray Burst 200424A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Fri 24 Apr 20 12:07:20 UT
NOTICE_TYPE:    INTEGRAL Wakeup
TRIGGER_NUM:    8606,   Sub_Num: 0
GRB_RA:         307.4812d {+20h 29m 55s} (J2000),
                307.8157d {+20h 31m 16s} (current),
                306.6555d {+20h 26m 37s} (1950)
GRB_DEC:        -39.7222d {-39d 43' 19"} (J2000),
                -39.6531d {-39d 39' 10"} (current),
                -39.8900d {-39d 53' 23"} (1950)
GRB_ERROR:      3.28 [arcmin, radius, statistical only]
GRB_INTEN:      8.09 [sigma]
GRB_TIME:       43630.85 SOD {12:07:10.85} UT
GRB_DATE:       18963 TJD;   115 DOY;   20/04/24
SC_RA:          300.99 [deg] (J2000)
SC_DEC:         -39.12 [deg] (J2000)
SUN_POSTN:       32.50d {+02h 10m 00s}  +13.11d {+13d 06' 39"}
SUN_DIST:        94.32 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      48.79d {+03h 15m 09s}  +14.64d {+14d 38' 27"}
MOON_DIST:      107.64 [deg]
GAL_COORDS:       1.78,-35.21 [deg] galactic lon,lat of the burst
ECL_COORDS:     299.89,-20.09 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=5.0000 and Time_Error=5.0000.  
COMMENTS:       Possibly real GRB event

red DSS finding chart ps-file

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Fri 24 Apr 20 12:07:27 UT
NOTICE_TYPE:    INTEGRAL Refined
TRIGGER_NUM:    8606,   Sub_Num: 1
GRB_RA:         307.5031d {+20h 30m 01s} (J2000),
                307.8376d {+20h 31m 21s} (current),
                306.6775d {+20h 26m 43s} (1950)
GRB_DEC:        -39.7240d {-39d 43' 25"} (J2000),
                -39.6549d {-39d 39' 17"} (current),
                -39.8919d {-39d 53' 30"} (1950)
GRB_ERROR:      2.67 [arcmin, radius, statistical only]
GRB_INTEN:      18.42 [sigma]
GRB_TIME:       43632.82 SOD {12:07:12.82} UT
GRB_DATE:       18963 TJD;   115 DOY;   20/04/24
SC_RA:          300.99 [deg] (J2000)
SC_DEC:         -39.12 [deg] (J2000)
SUN_POSTN:       32.50d {+02h 10m 00s}  +13.11d {+13d 06' 39"}
SUN_DIST:        94.30 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      48.79d {+03h 15m 09s}  +14.64d {+14d 38' 29"}
MOON_DIST:      107.63 [deg]
GAL_COORDS:       1.78,-35.23 [deg] galactic lon,lat of the burst
ECL_COORDS:     299.91,-20.10 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=0.0399 and Time_Error=2.0000.  
COMMENTS:       Possibly real GRB event

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Fri 24 Apr 20 12:08:08 UT
NOTICE_TYPE:    INTEGRAL Refined
TRIGGER_NUM:    8606,   Sub_Num: 2
GRB_RA:         307.5139d {+20h 30m 03s} (J2000),
                307.8484d {+20h 31m 24s} (current),
                306.6885d {+20h 26m 45s} (1950)
GRB_DEC:        -39.7074d {-39d 42' 26"} (J2000),
                -39.6383d {-39d 38' 17"} (current),
                -39.8754d {-39d 52' 30"} (1950)
GRB_ERROR:      2.53 [arcmin, radius, statistical only]
GRB_INTEN:      37.27 [sigma]
GRB_TIME:       43680.85 SOD {12:08:00.85} UT
GRB_DATE:       18963 TJD;   115 DOY;   20/04/24
SC_RA:          300.99 [deg] (J2000)
SC_DEC:         -39.12 [deg] (J2000)
SUN_POSTN:       32.50d {+02h 10m 00s}  +13.11d {+13d 06' 39"}
SUN_DIST:        94.29 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      48.79d {+03h 15m 10s}  +14.64d {+14d 38' 35"}
MOON_DIST:      107.62 [deg]
GAL_COORDS:       1.80,-35.23 [deg] galactic lon,lat of the burst
ECL_COORDS:     299.92,-20.09 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=50.0000 and Time_Error=50.0000.  
COMMENTS:       Possibly real GRB event

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Fri 24 Apr 20 12:10:20 UT
NOTICE_TYPE:    INTEGRAL Refined
TRIGGER_NUM:    8606,   Sub_Num: 3
GRB_RA:         307.5183d {+20h 30m 04s} (J2000),
                307.8528d {+20h 31m 25s} (current),
                306.6929d {+20h 26m 46s} (1950)
GRB_DEC:        -39.7094d {-39d 42' 33"} (J2000),
                -39.6403d {-39d 38' 24"} (current),
                -39.8774d {-39d 52' 38"} (1950)
GRB_ERROR:      2.53 [arcmin, radius, statistical only]
GRB_INTEN:      35.85 [sigma]
GRB_TIME:       43724.85 SOD {12:08:44.85} UT
GRB_DATE:       18963 TJD;   115 DOY;   20/04/24
SC_RA:          300.99 [deg] (J2000)
SC_DEC:         -39.12 [deg] (J2000)
SUN_POSTN:       32.50d {+02h 10m 00s}  +13.11d {+13d 06' 41"}
SUN_DIST:        94.29 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      48.81d {+03h 15m 15s}  +14.65d {+14d 38' 57"}
MOON_DIST:      107.64 [deg]
GAL_COORDS:       1.80,-35.24 [deg] galactic lon,lat of the burst
ECL_COORDS:     299.92,-20.09 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=100.0000 and Time_Error=100.0000.  
COMMENTS:       Possibly real GRB event

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Fri 24 Apr 20 12:54:46 UT
NOTICE_TYPE:    INTEGRAL Offline
TRIGGER_NUM:    8606,   Sub_Num: 3
GRB_RA:         307.5056d {+20h 30m 01s} (J2000),
                307.8400d {+20h 31m 22s} (current),
                306.6802d {+20h 26m 43s} (1950)
GRB_DEC:        -39.6937d {-39d 41' 36"} (J2000),
                -39.6246d {-39d 37' 28"} (current),
                -39.8616d {-39d 51' 41"} (1950)
GRB_ERROR:      1.50 [arcmin, radius, statistical only]
GRB_INTEN:      37.27 [sigma]
GRB_TIME:       43680.85 SOD {12:08:00.85} UT
GRB_DATE:       18963 TJD;   115 DOY;   20/04/24
SC_RA:          300.99 [deg] (J2000)
SC_DEC:         -39.12 [deg] (J2000)
SUN_POSTN:       32.53d {+02h 10m 07s}  +13.12d {+13d 07' 17"}
SUN_DIST:        94.32 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      49.18d {+03h 16m 42s}  +14.77d {+14d 46' 15"}
MOON_DIST:      108.00 [deg]
GAL_COORDS:       1.82,-35.23 [deg] galactic lon,lat of the burst
ECL_COORDS:     299.92,-20.07 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=50.0000 and Time_Error=50.0000.  
COMMENTS:       refined_coordinates_after_offline_analysis

GCN Circular #27634
S.Mereghetti (INAF, IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo, V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC, Versoix), and J.Borkowski (CAMK, Torun) report:
A long gamma ray burst lasting at least 70 s has been detected by IBAS in the IBIS/ISGRI data at 12:07:10 UT of April 24, 2020
The refined coordinates (J2000) are:
```
R.A. = 307.5057   deg
DEC. = -39.6939 deg
```
with an uncertainty of 1.5 arcmin (90% c.l.).
The burst light curve is affected by telemetry saturation due to the burst brightness. Therefore we can provide only a lower limit on its 20-200 keV fluence of 3e-6 erg/cm2 over a 70 s integration time.
A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html
GCN Circular #27636
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the INTEGRAL GRB 200424A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00020989
Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the INTEGRAL event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
GCN Circular #27637
R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration:
We observed INTEGRAL GRB 200424A (Mereghetti et al., GCN 27634) with the LCO 1-m Sinistro instrument at the Siding Spring Observatory, Australia site, on April 24, from 18:48 to 19:23 UT (corresponding to 6.68 to 7.27 hours from the GRB trigger time) with the Bessel I and R filters.
We performed a series of 5x240s exposures in R and 4x240s in I. We do not detect any fading sources in the individual frames (or in stacked images). Using the USNO-B.1 catalog as reference, we obtain the following 3-sigma upper limits:
R > 24.83
I > 22.93
These magnitudes are not corrected for galactic extinction.
R.S. is funded by NSF AST grant #1831682
GCN Circular #27640
M. Perri (ASDC), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the INTEGRAL-detected burst GRB 200424A (Mereghetti et al. GCN Circ. 27634), collecting 5.0 ks of Photon Counting (PC) mode data between T0+13.2 ks and T0+30.7 ks.
One uncatalogued X-ray source has been detected consistent with being within the INTEGRAL position, however it is below the RASS limit and shows no definitive signs of fading. Therefore, at the present time we cannot confirm this as the afterglow. Details of this source are given below:
Source 1:
```
  RA (J2000.0):  307.5055  =  20:30:01.31
  Dec (J2000.0): -39.7001  =  -39:42:00.5
  Error: 3.0 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (8.3 [+1.7, -1.6])e-3 ct s^-1   
  Distance: 22 arcsec from INTEGRAL position.
  Flux: (2.68 [+0.55, -0.52])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
```
Seven uncatalogued sources were also detected too far from the GRB position to be likely afterglow candidates.
The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00020989.
This circular is an official product of the Swift-XRT team.
GCN Circular #27642
S. Gupta, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data showed the detection of a long GRB 200424A, which was also detected by INTEGRAL (Mereghetti S. et al., GCN #27634), Swift(Evans P. et al., GCN #27636) and LCO (Strausbaugh R. et al., GCN #27637).
The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with the strongest peak at 2020-04-24 12:07:18.525 UT. The measured peak count rate associated with the burst is 232 +/- 28 cts/s above the background in the combined data of four quadrants, with a total of 1849 +/- 44 cts. The local mean background count rate was 596 +/- 1 cts/s. Using cumulative rates, we measure a T90 of 43.3 +/- 0.02 s.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.
CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.
GCN Circular #27648
N. P. M. Kuin (UCL-MSSL) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the INTEGRAL GRB 200424A (Mereghetti et al. GCN Circ. 27634) between T0+17 ks and T0+31 ks, where T0 = 2020-04-24 12:06:45 UT. We report here the UOT results for source #1 found by the Swift/XRT (D'Avanzo et al., GCN Circ. 27640).
Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(ks)   T_stop(ks)      Exp(s)         Mag

v                   18           30          236         >19.1
b                   17           30          236         >20.2
u                   17           30          236         >19.9
w1                  17           30          492         >19.9
m2                  17           31         2678         >20.8
w2                  17           30          944         >20.4
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #27676
M. Perri (ASDC), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has conducted further observations of the field of the INTEGRAL-detected burst GRB 200424A (Mereghetti et al. GCN Circ. 27634). The observations now extend from T0+17.1 ks to T0+633.1 ks.
Of the sources reported by Perri et al. (GCN Circ. 27640), "Source 1" is fading with 3-sigma significance, and is therefore likely the GRB afterglow. Using 1970 s of PC mode data and 1 UVOT image, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 307.50547, -39.70013 which is equivalent to:
```
RA (J2000): 20h 30m 01.31s
Dec(J2000): -39d 42' 00.5"
```
with an uncertainty of 3.0 arcsec (radius, 90% confidence). This position is 22 arcsec from the INTEGRAL position. The source is fading with alpha >0.3.
The results of the XRT-team automatic analysis of the likely afterglow are at https://www.swift.ac.uk/ToO_GRBs/00020989/Source1.php. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00020989.
This circular is an official product of the Swift-XRT team.

Back to JG's homepage

Jochen Greiner, last update: 02-May-2020 [Disclaimer]