Gamma-ray Burst 190424A

(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 24 Apr 19 10:01:01 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     900285,   Seg_Num: 0
GRB_RA:           48.681d {+03h 14m 43s} (J2000),
                  48.958d {+03h 15m 50s} (current),
                  47.964d {+03h 11m 51s} (1950)
GRB_DEC:         +20.233d {+20d 14' 00"} (J2000),
                 +20.304d {+20d 18' 15"} (current),
                 +20.048d {+20d 02' 54"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2700 [cnts]    Image_Peak=111 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   148     E_range: 25-100 keV
BKG_INTEN:       15713 [cnts]
BKG_TIME:        36025.20 SOD {10:00:25.20} UT
BKG_DUR:         8 [sec]
GRB_DATE:        18597 TJD;   114 DOY;   19/04/24
GRB_TIME:        36043.19 SOD {10:00:43.19} UT
GRB_PHI:         -74.86 [deg]
GRB_THETA:        33.71 [deg]
SOLN_STATUS:     0x83
RATE_SIGNIF:     15.16 [sigma]
IMAGE_SIGNIF:    6.72 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  -3 -100  +0 -95  +0 
SUN_POSTN:        31.70d {+02h 06m 49s}  +12.83d {+12d 49' 60"}
SUN_DIST:         18.13 [deg]   Sun_angle= -1.2 [hr] (East of Sun)
MOON_POSTN:      276.39d {+18h 25m 35s}  -22.02d {-22d 00' 58"}
MOON_DIST:       135.91 [deg]
MOON_ILLUM:      74 [%]
GAL_COORDS:      162.92,-31.29 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       51.69,  2.12 [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:        Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.  
COMMENTS:        This trigger occurred at longitude,latitude = 93.12,4.10 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 24 Apr 19 10:05:10 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     900285,   Seg_Num: 0
GRB_RA:           48.681d {+03h 14m 43s} (J2000),
                  48.958d {+03h 15m 50s} (current),
                  47.964d {+03h 11m 51s} (1950)
GRB_DEC:         +20.233d {+20d 14' 00"} (J2000),
                 +20.304d {+20d 18' 15"} (current),
                 +20.048d {+20d 02' 54"} (1950)
GRB_DATE:        18597 TJD;   114 DOY;   19/04/24
GRB_TIME:        36043.19 SOD {10:00:43.19} UT
TRIGGER_INDEX:   148
GRB_PHI:         -74.86 [deg]
GRB_THETA:        33.71 [deg]
DELTA_TIME:      -37.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x83
RATE_SIGNIF:     15.16 [sigma]
IMAGE_SIGNIF:    6.72 [sigma]
LC_URL:          sw00900285000msb.lc
SUN_POSTN:        31.71d {+02h 06m 49s}  +12.83d {+12d 50' 03"}
SUN_DIST:         18.13 [deg]   Sun_angle= -1.2 [hr] (East of Sun)
MOON_POSTN:      276.43d {+18h 25m 44s}  -22.02d {-22d 01' 03"}
MOON_DIST:       135.87 [deg]
MOON_ILLUM:      74 [%]
GAL_COORDS:      162.92,-31.29 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       51.69,  2.12 [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:        Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.  
COMMENTS:        This trigger occurred at longitude,latitude = 93.12,4.10 [deg].

GCN Circular #24163
J.D. Gropp (PSU), N. J. Klingler (PSU), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team:
At 10:00:43 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 190424A (trigger=900285). Swift did not slew to the burst due to an observing constraint. The BAT on-board calculated location is RA, Dec 48.681, +20.233 which is
```
   RA(J2000) = 03h 14m 43s
   Dec(J2000) = +20d 14' 00"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single FRED peak structure with a duration of about 20 sec. The peak count rate was ~900 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 17:34 UT on 2019 June 30. There will thus be no XRT or UVOT data for this trigger before this time.
Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu). 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 #24164
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), J.D. Gropp (PSU), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), 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 190424A (trigger #900285) (Group, et al., GCN Circ. 24163). The BAT ground-calculated position is RA, Dec = 48.693, 20.239 deg which is
```
   RA(J2000)  =  03h 14m 46.2s
   Dec(J2000) = +20d 14' 19.9"
```
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 41%.
The mask-weighted light curve shows a single, fairly symmetrical pulse starting at T-2 seconds, peaking at T+2 sec, and declining to background by T+12 sec. The spacecraft slewed away from the burst location at T+80 sec. T90 (15-350 keV) is 10.6 +- 2.3 sec (estimated error including systematics).
The time-averaged spectrum from T-1.31 to T+12.04 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.45 +- 0.13. 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+1.10 sec in the 15-150 keV band is 2.0 +- 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/900285/BA/

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Jochen Greiner, last update: 24-Apr-2019 [Disclaimer]