Late-time HST and JWST Observations of GRB 221009A: Evidence for a Break in the Light Curve at 50 Days

Fuente: arXiv
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Autori principali: Sears, Huei, Chornock, Ryan, Blanchard, Peter, Margutti, Raffaella, Villar, V. Ashley, Pierel, Justin, Vallely, Patrick J., Alexander, Kate D., Berger, Edo, Eftekhari, Tarraneh, Jacobson-Galan, Wynn V., Laskar, Tanmoy, LeBaron, Natalie, Metzger, Brian D., Milisavljevic, Dan
Natura: Preprint
Pubblicazione: 2024
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author Sears, Huei
Chornock, Ryan
Blanchard, Peter
Margutti, Raffaella
Villar, V. Ashley
Pierel, Justin
Vallely, Patrick J.
Alexander, Kate D.
Berger, Edo
Eftekhari, Tarraneh
Jacobson-Galan, Wynn V.
Laskar, Tanmoy
LeBaron, Natalie
Metzger, Brian D.
Milisavljevic, Dan
author_facet Sears, Huei
Chornock, Ryan
Blanchard, Peter
Margutti, Raffaella
Villar, V. Ashley
Pierel, Justin
Vallely, Patrick J.
Alexander, Kate D.
Berger, Edo
Eftekhari, Tarraneh
Jacobson-Galan, Wynn V.
Laskar, Tanmoy
LeBaron, Natalie
Metzger, Brian D.
Milisavljevic, Dan
contents GRB 221009A is one of the brightest transients ever observed with the highest peak gamma-ray flux for a gamma-ray burst (GRB). A type Ic-BL supernova (SN), SN 2022xiw, was definitively detected in late-time JWST spectroscopy (t = 195 days, observer-frame). However, photometric studies have found SN 2022xiw to be less luminous (10-70%) than the canonical GRB-SN, SN 1998bw. We present late-time Hubble Space Telescope (HST)/WFC3 and JWST/NIRCam imaging of the afterglow and host galaxy of GRB 221009A at t ~ 185, 277, and 345 days post-trigger. Our joint archival ground, HST, and JWST light curve fits show strong support for a break in the light curve decay slope at t = 50 +/- 10 days (observer-frame) and a supernova at $< 1.5 \times$ the optical/NIR flux of SN 1998bw. This break is consistent with an interpretation as a jet break when requiring slow-cooling electrons in a wind medium with the electron energy spectral index, p > 2, and $ν_m < ν_c$. Our light curve and joint HST/JWST spectral energy distribution (SED) also show evidence for the late-time emergence of a bluer component in addition to the fading afterglow and supernova. We find consistency with the interpretations that this source is either a young, massive, low-metallicity star cluster or a scattered light echo of the afterglow with a SED shape of $f_ν \propto ν^{2.0\pm1.0}$.
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id arxiv_https___arxiv_org_abs_2412_02663
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Late-time HST and JWST Observations of GRB 221009A: Evidence for a Break in the Light Curve at 50 Days
Sears, Huei
Chornock, Ryan
Blanchard, Peter
Margutti, Raffaella
Villar, V. Ashley
Pierel, Justin
Vallely, Patrick J.
Alexander, Kate D.
Berger, Edo
Eftekhari, Tarraneh
Jacobson-Galan, Wynn V.
Laskar, Tanmoy
LeBaron, Natalie
Metzger, Brian D.
Milisavljevic, Dan
High Energy Astrophysical Phenomena
GRB 221009A is one of the brightest transients ever observed with the highest peak gamma-ray flux for a gamma-ray burst (GRB). A type Ic-BL supernova (SN), SN 2022xiw, was definitively detected in late-time JWST spectroscopy (t = 195 days, observer-frame). However, photometric studies have found SN 2022xiw to be less luminous (10-70%) than the canonical GRB-SN, SN 1998bw. We present late-time Hubble Space Telescope (HST)/WFC3 and JWST/NIRCam imaging of the afterglow and host galaxy of GRB 221009A at t ~ 185, 277, and 345 days post-trigger. Our joint archival ground, HST, and JWST light curve fits show strong support for a break in the light curve decay slope at t = 50 +/- 10 days (observer-frame) and a supernova at $< 1.5 \times$ the optical/NIR flux of SN 1998bw. This break is consistent with an interpretation as a jet break when requiring slow-cooling electrons in a wind medium with the electron energy spectral index, p > 2, and $ν_m < ν_c$. Our light curve and joint HST/JWST spectral energy distribution (SED) also show evidence for the late-time emergence of a bluer component in addition to the fading afterglow and supernova. We find consistency with the interpretations that this source is either a young, massive, low-metallicity star cluster or a scattered light echo of the afterglow with a SED shape of $f_ν \propto ν^{2.0\pm1.0}$.
title Late-time HST and JWST Observations of GRB 221009A: Evidence for a Break in the Light Curve at 50 Days
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2412.02663