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The Panchromatic Afterglow of GW170817: The full uniform dataset, modeling, comparison with previous results and implications

Makhathini, Sphesihle and Mooley, Kunal P. and Brightman, Murray and Hotokezaka, Kenta and Nayana, A. J. and Intema, Huib T. and Dobie, Dougal and Lenc, E. and Perley, Daniel A. and Fremling, Christoffer and Moldon, Javier and Lazzati, Davide and Kaplan, David L. and Balasubramanian, Arvind and Brown, Ian and Carbone, Dario and Chandra, Poonam and Corsi, Alessandra and Camilo, Fernando and Deller, Adam T. and Frail, Dale A. and Murphy, Tara and Murphy, Eric J. and Nakar, Ehud and Smirnov, Oleg and Beswick, Robert and Fender, Rob and Hallinan, Gregg and Heywood, Ian and Kasliwal, Mansi M. and Lee, Bomee and Lu, Wenbin and Rana, Javed and Perkins, S. J. and White, Sarah V. and Jozsa, Gyula I. and Hugo, Benjamin and Kamphuis, Peter (2020) The Panchromatic Afterglow of GW170817: The full uniform dataset, modeling, comparison with previous results and implications. . (Unpublished)

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We present the full panchromatic afterglow light curve data of GW170817, including new radio data as well as archival optical and X-ray data, between 0.5 and 940 days post-merger. By compiling all archival data, and reprocessing a subset of it, we have ensured that the panchromatic dataset is uniform and therefore immune to the differences in data processing or flux determination methods used by different groups. Simple power-law fits to the uniform afterglow light curve indicate a t^(0.86±0.04) rise, a t^(−1.90±0.12) decline, and a peak occurring at 155±4 days. The afterglow is optically thin throughout its evolution, consistent with a single spectral index (−0.569±0.002) across all epochs. This gives a precise and updated estimate of the electron power-law index, p=2.138±0.004. By studying the diffuse X-ray emission from the host galaxy, we place a conservative upper limit on the hot ionized ISM density, <0.01 cm⁻³, consistent with previous afterglow studies. Using the late-time afterglow data we rule out any long-lived neutron star remnant having magnetic field strength between 10^(10.4) G and 10¹⁶ G. Our fits to the afterglow data using an analytical model that includes VLBI proper motion from Mooley et al (2018), and a structured jet model that ignores the proper motion, indicates that the proper motion measurement needs to be considered while seeking an accurate estimate of the viewing angle.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Mooley, Kunal P.0000-0002-2557-5180
Brightman, Murray0000-0002-8147-2602
Hotokezaka, Kenta0000-0002-2502-3730
Intema, Huib T.0000-0002-5880-2730
Dobie, Dougal0000-0003-0699-7019
Lenc, E.0000-0002-9994-1593
Perley, Daniel A.0000-0001-8472-1996
Fremling, Christoffer0000-0002-4223-103X
Lazzati, Davide0000-0002-9190-662X
Kaplan, David L.0000-0001-6295-2881
Carbone, Dario0000-0002-6575-4642
Chandra, Poonam0000-0002-0844-6563
Camilo, Fernando0000-0002-1873-3718
Deller, Adam T.0000-0001-9434-3837
Murphy, Tara0000-0002-2686-438X
Murphy, Eric J.0000-0001-7089-7325
Nakar, Ehud0000-0002-4534-7089
Hallinan, Gregg0000-0002-7083-4049
Kasliwal, Mansi M.0000-0002-5619-4938
Lee, Bomee0000-0003-1954-5046
Lu, Wenbin0000-0002-1568-7461
Rana, Javed0000-0001-5605-1809
Additional Information:The MeerKAT telescope is operated by the South African Radio Astronomy Observatory, which is a facility of the National Research Foundation, an agency of the Department of Science and Innovation. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The authors thank the NRAO staff, especially Mark Claussen and Amy Mioduszewski, for scheduling the VLA observations. The Australia Telescope is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. We thank the staff of the GMRT that made these observations possible. GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. The MeerKAT telescope is operated by the South African Radio Astronomy Observatory, (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology. The authors are grateful to Schuyler van Dyk for helpful discussions. KPM is a Jansky Fellow of the National Radio Astronomy Observatory. DD is supported by an Australian Government Research Training Program Scholarship. TM acknowledges the support of the Australian Research Council through grant DP190100561. Parts of this research were conducted by the Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav), project number CE170100004. We acknowledge support by the GROWTH (Global Relay of Observatories Watching Transients Happen) project funded by the National Science Foundation PIRE (Partnership in International Research and Education) program under Grant No 1545949. DL acknowledges support from NASA grants 80NSSC18K1729 (Fermi) and NNX17AK42G (ATP), Chandra grant TM9-20002X, and NSF grant AST-1907955. This research has made use of NASA's Astrophysics Data System Bibliographic Services. CF gratefully acknowledges support of his research by the Heising-Simons Foundation. JM acknowledges financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709) and from the grant RTI2018-096228-B-C31 (MICIU/FEDER, EU). DLK was supported by NSF grant AST-1816492 PK is partially supported by the BMBF project 05A17PC2 for D-MeerKAT. Facility: VLA, ATCA, uGMRT, MeerKAT, eMERLIN, HST, Chandra, XMM-Newton Software: MIRIAD (Sault et al. 1995), CASA (McMullin et al. 2007), emcee (Foreman-Mackey et al. 2013), corner (Foreman-Mackey 2016) , CARACal (Ramatsoku et al. 2020), AOFlagger (Offringa et al. 2010), WSClean (Offringa et al. 2014), CubiCal (Kenyon et al. 2018), MeqTrees (Noordam & Smirnov 2010)
Group:Astronomy Department, Infrared Processing and Analysis Center (IPAC), Space Radiation Laboratory, NuSTAR
Funding AgencyGrant Number
National Research Foundation (South Africa)UNSPECIFIED
Department of Science and Innovation (South Africa)UNSPECIFIED
National Radio Astronomy ObservatoryUNSPECIFIED
Commonwealth Scientific and Industrial Research Organisation (CSIRO)UNSPECIFIED
Tata Institute of Fundamental ResearchUNSPECIFIED
South African Radio Astronomy Observatory (SARAO)UNSPECIFIED
Jansky FellowshipUNSPECIFIED
Australian Research CouncilDP190100561
Australian Research CouncilCE170100004
Heising-Simons FoundationUNSPECIFIED
Severo OchoaSEV-2017-0709
Ministerio de Ciencia, Innovación y Universidades (MICIU)RTI2018-096228-B-C31
Fondo Europeo de Desarrollo Regional (FEDER)UNSPECIFIED
Bundesministerium für Bildung und Forschung (BMBF)05A17PC2
Subject Keywords:gravitational waves - stars: neutron - radio continuum: stars - X-rays: stars - infrared: stars
Record Number:CaltechAUTHORS:20200604-151511891
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103720
Deposited By: George Porter
Deposited On:05 Jun 2020 14:09
Last Modified:05 Jun 2020 14:09

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