GCN Circular 36109
Subject
GRB 240415A: Prompt Swift-XRT observations
Date
2024-04-15T08:00:44Z (23 days ago)
From
P.A. Evans at U. Leicester <pae9@leicester.ac.uk>
Via
email
P.A. Evans (U. Leicester), K.L. Page (U. Leicester) and M. J. Moss (GSFC)
report on behalf of the Swift-XRT team:
The automated Swift slew to GRB 240415A (BAT trigger 1221874; Moss et al.,
GCN Circ. 36108) was delayed due to an Earth limb constraint.
The XRT began observing the field at 07:21:58.2 UT, 3305 seconds
after the BAT trigger. Using promptly downlinked data we find an
uncatalogued X-ray source located at RA, Dec 129.19096 73.14608 which
is equivalent to:
RA(J2000) = 08h 36m 45.83s
Dec(J2000) = +73d 08' 45.9"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This is
105 arcseconds from the BAT position, inside the BAT error circle. This
position may be improved as more data are received; the latest position
is available at https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (2.49 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 6.5
(+3.49/-2.94) x 10^21 cm^-2 (90% confidence).