Abstract
| Original language | English |
|---|---|
| Article number | 88 |
| Number of pages | 8 |
| Journal | Astrophysical Journal |
| Volume | 833 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 8 Dec 2016 |
Fingerprint
Keywords
- astro-ph.HE
Cite this
A Reverse Shock in GRB 160509A. / Laskar, Tanmoy; Alexander, Kate D.; Berger, Edo; Fong, Wen-fai; Margutti, Raffaella; Shivvers, Isaac; Williams, Peter K. G.; Kopac, Drejc; Kobayashi, Shiho; Mundell, Carole; Gomboc, Andreja; Zheng, WeiKang; Menten, Karl M.; Graham, Melissa L.; Filippenko, Alexei V.
In: Astrophysical Journal, Vol. 833, No. 1, 88, 08.12.2016.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A Reverse Shock in GRB 160509A
AU - Laskar, Tanmoy
AU - Alexander, Kate D.
AU - Berger, Edo
AU - Fong, Wen-fai
AU - Margutti, Raffaella
AU - Shivvers, Isaac
AU - Williams, Peter K. G.
AU - Kopac, Drejc
AU - Kobayashi, Shiho
AU - Mundell, Carole
AU - Gomboc, Andreja
AU - Zheng, WeiKang
AU - Menten, Karl M.
AU - Graham, Melissa L.
AU - Filippenko, Alexei V.
PY - 2016/12/8
Y1 - 2016/12/8
N2 - We present the second multi-frequency radio detection of a reverse shock in a $\gamma$-ray burst. By combining our extensive radio observations of the Fermi-LAT GRB 160509A at $z = 1.17$ up to $20$ days after the burst with Swift X-ray observations and ground-based optical and near-infrared data, we show that the afterglow emission comprises distinct reverse shock and forward shock contributions: the reverse shock emission dominates in the radio band at $\lesssim10~$days, while the forward shock emission dominates in the X-ray, optical, and near-infrared bands. Through multi-wavelength modeling, we determine a circumburst density of $n_0\approx10^{-3}~$cm$^{-3}$, supporting our previous suggestion that a low-density circumburst environment is conducive to the production of long-lasting reverse shock radiation in the radio band. We infer the presence of a large excess X-ray absorption column, $N_{\rm H} \approx 1.5\times10^{22}~$cm$^{-2}$, and a high rest-frame optical extinction, $A_{\rm V}\approx3.4~$mag. We identify a jet break in the X-ray light curve at $t_{\rm jet}\approx6~$d, and thus derive a jet opening angle of $\theta_{\rm jet}\approx4~$deg, yielding a beaming-corrected kinetic energy and radiated $\gamma$-ray energy of $E_{\rm K}\approx4\times10^{50}~$erg and $E_{\gamma}\approx1.3\times10^{51}~$erg ($1$-$10^4~$keV, rest frame), respectively. Consistency arguments connecting the forward and reverse shocks suggest a deceleration time of $t_{\rm dec} \approx 460~$s$~\approx T_{90}$, a Lorentz factor of $\Gamma(t_{\rm dec})\approx330$, and a reverse shock to forward shock fractional magnetic energy density ratio of $R_{\rm B}\equiv\epsilon_{\rm B,RS}/\epsilon_{\rm B,FS}\approx8$.
AB - We present the second multi-frequency radio detection of a reverse shock in a $\gamma$-ray burst. By combining our extensive radio observations of the Fermi-LAT GRB 160509A at $z = 1.17$ up to $20$ days after the burst with Swift X-ray observations and ground-based optical and near-infrared data, we show that the afterglow emission comprises distinct reverse shock and forward shock contributions: the reverse shock emission dominates in the radio band at $\lesssim10~$days, while the forward shock emission dominates in the X-ray, optical, and near-infrared bands. Through multi-wavelength modeling, we determine a circumburst density of $n_0\approx10^{-3}~$cm$^{-3}$, supporting our previous suggestion that a low-density circumburst environment is conducive to the production of long-lasting reverse shock radiation in the radio band. We infer the presence of a large excess X-ray absorption column, $N_{\rm H} \approx 1.5\times10^{22}~$cm$^{-2}$, and a high rest-frame optical extinction, $A_{\rm V}\approx3.4~$mag. We identify a jet break in the X-ray light curve at $t_{\rm jet}\approx6~$d, and thus derive a jet opening angle of $\theta_{\rm jet}\approx4~$deg, yielding a beaming-corrected kinetic energy and radiated $\gamma$-ray energy of $E_{\rm K}\approx4\times10^{50}~$erg and $E_{\gamma}\approx1.3\times10^{51}~$erg ($1$-$10^4~$keV, rest frame), respectively. Consistency arguments connecting the forward and reverse shocks suggest a deceleration time of $t_{\rm dec} \approx 460~$s$~\approx T_{90}$, a Lorentz factor of $\Gamma(t_{\rm dec})\approx330$, and a reverse shock to forward shock fractional magnetic energy density ratio of $R_{\rm B}\equiv\epsilon_{\rm B,RS}/\epsilon_{\rm B,FS}\approx8$.
KW - astro-ph.HE
UR - https://doi.org/10.3847/1538-4357/833/1/88
U2 - 10.3847/1538-4357/833/1/88
DO - 10.3847/1538-4357/833/1/88
M3 - Article
VL - 833
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 88
ER -