////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  24163
SUBJECT: GRB 190424A: Swift detection of a burst
DATE:    19/04/24 10:13:57 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

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/)

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  24164
SUBJECT: GRB 190424A: Swift-BAT refined analysis
DATE:    19/04/24 21:26:50 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

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/