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GCN Circular 32767

GRB 221009A: LEIA X-ray Afterglow Detection
2022-10-16T02:21:05Z (2 years ago)
LEIA Team at NAOC/CAS <>
Y. Liu, C. Zhang, Z.X. Ling, H.Q. Cheng, C.Z. Cui, D.W. Fan, H.B. Hu,

M.H. Huang, C.C. Jin, D.Y. Li, H.Y. Liu, H. Sun, H.W. Pan, W.X. Wang,

Y.F. Xu, M. Zhang, W.D. Zhang, D.H. Zhao, and W. Yuan (NAOC, CAS),

report on behalf of the LEIA and Einstein Probe team:


LEIA (Lobster Eye Imager for Astronomy) has performed one

follow-up observation of GRB 221009A detected by Swift/BAT

(Dichiara et al., GCN 32632, Kennea et al., GCN 32635), Fermi-GBM

(Lesage et al., GCN 32642, Veres et al., GCN 32636), Fermi-LAT

(Bissaldi et al. GCN 32637, Pillera et al., GCN 32658), AGILE-MCAL

(Ursi et al., GCN 32650), AGILE-GRID (Piano et al. GCN 32657),

INTEGRAL SPI/ACS (Gotz et al., GCN 32660), Konus-Wind

(Frederiks et al., GCN 32668), HEBS (Liu et al., GCN 32751), at a 

redshift of z = 0.151 (de Ugarte Postigo et al., GCN 32648; 

Castro-Tirado et al., GCN 32686).


The pointed observation was conducted from 2022-10-12T05:31:48

to 2022-10-12T05:51:39 with a net exposure of 1012 s. The X-ray

afterglow of GRB 221009A is detected at a significance of 4.9 sigma.

Assuming an absorbed power-law model with a photon index of 2.0,

a Galactic absorption of 5.4 x 10^21 cm^-2 (Willingale et al. 2013;

GCN #32651), and an intrinsic absorption of 1.1 x 10^22 cm^-2 at a

redshift of 0.151 (GCN #32648), the unabsorbed flux in the 0.5 - 4.0 keV

band is (1.8+/-0.4) x 10^-10 ergs/cm^2/s.


LEIA (Zhang et al, ApJL submitted) is a soft X-ray monitor (0.5 - 4.0 keV)

with a FoV of 340 square degrees aboard the SATech-01 satellite of the CAS,

launched on July 27, 2022. The above result is preliminary and the final

result will be published elsewhere.
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