A Caltech Library Service

GW170817 4.5 Yr After Merger: Dynamical Ejecta Afterglow Constraints

Balasubramanian, Arvind and Corsi, Alessandra and Mooley, Kunal P. and Hotokezaka, Kenta and Kaplan, David L. and Frail, Dale A. and Hallinan, Gregg and Lazzati, Davide and Murphy, Eric J. (2022) GW170817 4.5 Yr After Merger: Dynamical Ejecta Afterglow Constraints. Astrophysical Journal, 938 (1). Art. No. 12. ISSN 0004-637X. doi:10.3847/1538-4357/ac9133.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


GW170817 is the first binary neutron star (NS) merger detected in gravitational waves (GWs) and photons, and so far remains the only GW event of its class with a definitive electromagnetic counterpart. Radio emission from the structured jet associated with GW170817 has faded below the sensitivity achievable via deep radio observations with the most sensitive radio arrays currently in operation. Hence, we now have the opportunity to probe the radio re-brightening that some models predict, which should emerge at late times from the interaction of the dynamically stripped merger ejecta with the interstellar medium. Here we present the latest results from our deep radio observations of the GW170817 field with the Karl G. Jansky Very Large Array (VLA), 4.5 yr after the merger. Our new data at 3 GHz do not show any compelling evidence for emission in excess to the tail of the jet afterglow (<3.3 μJy), confirming our previous results. We thus set new constraints on the dynamical ejecta afterglow models. These constraints favor single-speed ejecta with energies ≲10⁵⁰ erg (for an ejecta speed of β₀ = 0.5), or steeper energy–speed distributions of the kilonova ejecta. Our results also suggest larger values of the cold, nonrotating maximum NS mass in equal-mass scenarios. However, without a detection of the dynamical ejecta afterglow, obtaining precise constraints on the NS equation of state remains challenging.

Item Type:Article
Related URLs:
URLURL TypeDescription
Balasubramanian, Arvind0000-0003-0477-7645
Corsi, Alessandra0000-0001-8104-3536
Mooley, Kunal P.0000-0002-2557-5180
Hotokezaka, Kenta0000-0002-2502-3730
Kaplan, David L.0000-0001-6295-2881
Hallinan, Gregg0000-0002-7083-4049
Lazzati, Davide0000-0002-9190-662X
Murphy, Eric J.0000-0001-7089-7325
Additional Information:A.B. and A.C. acknowledge support from NSF AST-1907975. K.P.M. and G.H. acknowledge support from the National Science Foundation grant AST-1911199. D.L. acknowledges support from NSF grant AST-1907955. D.K. is supported by NSF grant AST-1816492. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
Group:Astronomy Department
Funding AgencyGrant Number
Issue or Number:1
Record Number:CaltechAUTHORS:20221019-343672700.8
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:117494
Deposited By: Research Services Depository
Deposited On:28 Oct 2022 15:48
Last Modified:28 Oct 2022 15:48

Repository Staff Only: item control page