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GCN Circular 37670

Subject
GRB 241001A: Swift-XRT observations
Date
2024-10-02T07:57:26Z (14 days ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
J.P. Osborne (U. Leicester), E. Ambrosi  (INAF-IASFPA) , M. Capalbi
(INAF-IASFPA), M. Perri (SSDC & INAF-OAR), D.N. Burrows (PSU), M. A.
Williams (PSU), S. Dichiara (PSU), K.L. Page (U. Leicester) and P.A.
Evans (U. Leicester) reports on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
SVOM/ECLAIRs-detected burst GRB 241001A, collecting 3.3 ks of Photon
Counting (PC) mode data between T0+6.4 ks and T0+13.6 ks. 

Four uncatalogued X-ray sources have been detected, however none of
them is above the RASS limit or shows definitive signs of fading.
Therefore, at the present time we cannot identify which, if any, is the
afterglow. Details of these sources are given below:

Source 1:
  RA (J2000.0):  20.4336  =  01:21:44.05
  Dec (J2000.0): -43.4616  =  -43:27:41.9
  Error: 7.8 arcsec (radius, 90% conf.)
  Count-rate: (2.09 [+1.25, -0.92])e-3 ct s^-1	 
  Distance: 261 arcsec from SVOM/ECLAIRs position.
  Flux: (6.1 [+3.7, -2.7])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000.0):  20.5530  =  01:22:12.71
  Dec (J2000.0): -43.4752  =  -43:28:30.6
  Error: 3.4 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: 0.0167 [+0.0029, -0.0027] ct s^-1   
  Distance: 397 arcsec from SVOM/ECLAIRs position.
  Flux: (7.1 +/- 1.2)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 3:
  RA (J2000.0):  20.4876  =  01:21:57.02
  Dec (J2000.0): -43.3786  =  -43:22:43.1
  Error: 6.2 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (4.9 [+1.9, -1.5])e-3 ct s^-1   
  Distance: 583 arcsec from SVOM/ECLAIRs position.
  Flux: (4.6 [+1.8, -1.4])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 5:
  RA (J2000.0):  20.5067  =  01:22:1.60
  Dec (J2000.0): -43.4924  =  -43:29:32.5
  Error: 7.6 arcsec (radius, 90% conf.)
  Count-rate: (2.06 [+1.24, -0.91])e-3 ct s^-1	 
  Distance: 262 arcsec from SVOM/ECLAIRs position.
  Flux: (9.9 [+6.0, -4.4])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

We note that Source 2 is spatially consistent with the optical
afterglow candidate reported in Izzo & Malesani, GCN #37667Not found
 
 
, adding
credence to this being the real afterglow.

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/00021719.

This circular is an official product of the Swift-XRT team.