Publication detail

The peak flux of GRB 221009A measured with GRBAlpha

RIPA, J. TAKAHASHI, H. FUKAZAWA, Y. WERNER, N. MUNZ, F. et al.

Original Title

The peak flux of GRB 221009A measured with GRBAlpha

Type

journal article in Web of Science

Language

English

Original Abstract

Context. On 2022 October 9 the brightest gamma-ray burst (GRB) ever observed lit up the high-energy sky. It was detected by a multitude of instruments, attracting the close attention of the GRB community, and saturated many detectors. Aims. GRBAlpha, a nano-satellite with a form factor of a 1U CubeSat, detected this extraordinarily bright long-duration GRB, GRB 221009A, without saturation but a ffected by pile-up. We present light curves of the prompt emission in 13 energy bands, from 80 keV to 950 keV, and performed a spectral analysis to calculate the peak flux and peak isotropic-equivalent luminosity. Methods. Since the satellite's attitude information is not available for the time of this GRB, more than 200 incident directions were probed in order to find the median luminosity and its systematic uncertainty. Results. We find that the peak flux in the 80 800 keV range (observer frame) was F-p (ph) = 1300+1200 200 ph cm (-2) s (-1), or F-p (erg) = 5:7+3:7 0:7 +/- 10 (-4) erg cm (-2) s (-1), and the fluence in the same energy range of the first GRB episode, which lasted 300 s and was observable by GRBAlpha, was S = 2:2+1:4 0:3 +/- 10 (-2) erg cm (-2), or S (bol) = 4:9+0:8 0:5 +/- 10 (-2) erg cm (-2) for the extrapolated range of 0:9 8690 keV. We infer the isotropic-equivalent released energy of the first GRB episode to be E-bol (iso) = 2:8+0:8 0:5 +/- 1054 erg in the 1 10 000 keV band (rest frame at z = 0:15). The peak isotropic-equivalent luminosity in the 92 920 keV range (rest frame) was L-p (iso) = 3 :7+2:5 0:5 +/- 10(52) erg s (-1), and the bolometric peak isotropic-equivalent luminosity was L-p;bol (iso) = 8:4(+2:5) (1:5 Chi) 10(52) erg s 1 (4 s scale) in the 1 10 000 keV range (rest frame). The peak emitted energy is E (*) (p) = E-p(1 + z) = 1120 +/- 470 keV. Our measurement of Lp;bol iso is consistent with the Yonetoku relation. It is possible that, due to the spectral evolution of this GRB and the orientation of GRBAlpha at the peak time, the true values of peak flux, fluence, Liso, and Eiso are even higher.

Keywords

gamma-ray burst: individual: GRB 221009A

Authors

RIPA, J.; TAKAHASHI, H.; FUKAZAWA, Y.; WERNER, N.; MUNZ, F.; et al.

Released

29. 8. 2023

Publisher

EDP SCIENCES S A

Location

17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE

ISBN

0004-6361

Periodical

ASTRONOMY & ASTROPHYSICS

Year of study

677

Number

neuvedeno

State

French Republic

Pages from

1

Pages to

7

Pages count

7

URL

https://www.aanda.org/articles/aa/pdf/2023/09/aa46128-23.pdf

BibTex

@article{BUT185073,
  author="RIPA, J. and TAKAHASHI, H. and FUKAZAWA, Y. and WERNER, N. and MUNZ, F. and et al.",
  title="The peak flux of GRB 221009A measured with GRBAlpha",
  journal="ASTRONOMY & ASTROPHYSICS",
  year="2023",
  volume="677",
  number="neuvedeno",
  pages="1--7",
  doi="10.1051/0004-6361/202346128",
  issn="0004-6361",
  url="https://www.aanda.org/articles/aa/pdf/2023/09/aa46128-23.pdf"
}