Abstract
We present 1-12 GHz Karl G. Jansky Very Large Array observations of nine off-nuclear persistent radio sources (PRSs) in nearby (z ≲ 0.055) dwarf galaxies, along with high-resolution European VLBI Network observations for one of them at 1.7 GHz. We explore the plausibility that these PRSs are associated with fast radio burst (FRB) sources by examining their properties—physical sizes, host-normalized offsets, spectral energy distributions (SEDs), radio luminosities, and light curves—and compare them to those of the PRSs associated with FRB 20121102A and FRB 20190520B, two known active galactic nuclei (AGN), and one likely AGN in our sample with comparable data, as well as other radio transients exhibiting characteristics analogous to FRB-PRSs. We identify a single source in our sample, J1136+2643, as the most promising FRB-PRS, based on its compact physical size and host-normalized offset. We further identify two sources, J0019+1507 and J0909+5655, with physical sizes comparable to FRB-PRSs, but which exhibit large offsets and flat spectral indices potentially indicative of a background AGN origin. We test the viability of neutron star wind nebula and hypernebula models for J1136+2643 and find that the physical size, luminosity, and SED of J1136+2643 are broadly consistent with these models. Finally, we discuss the alternative interpretation that the radio sources are instead powered by accreting massive black holes, and we outline future prospects and follow-up observations for differentiating between these scenarios.
Original language | English (US) |
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Article number | 133 |
Journal | Astrophysical Journal |
Volume | 973 |
Issue number | 2 |
DOIs | |
State | Published - Oct 1 2024 |
Funding
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The European VLBI Network is a joint facility of independent European, African, Asian, and North American radio astronomy institutes. Scientific results from data presented in this publication are derived from the following EVN project code(s): EO018. W. M. Keck Observatory and MMT Observatory access was supported by Northwestern University and the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. The authors are grateful for the helpful discussions with Dillon Dong and Joseph Michail. Y.D. is supported by the National Science Foundation Graduate Research Fellowship under grant No. DGE-1842165. The Fong Group at Northwestern acknowledges support by the National Science Foundation under grant Nos. AST-2206494 and AST-2308182 and CAREER grant No. AST-2047919. T.E. is supported by NASA through the NASA Hubble Fellowship grant HST-HF2-51504.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. S.B. is supported by the Dutch Research Council (NWO) Veni Fellowship (VI.Veni.212.058). Research by the AstroFlash group at the University of Amsterdam, ASTRON, and JIVE is supported in part by a Vici grant from the Dutch Scientific Research Council (Nederlandse Oranisatie voor Wetenschappelijk Onderzoek or NWO; PI Hessels; VI.C.192.045), as well as the European Union\u2019s Horizon 2020 research and innovation program through the ERC Advanced Grant \u201CEuroFlash\u201D (PI Hessels; grant agreement No. 101098079). W.F. gratefully acknowledges support by the David and Lucile Packard Foundation, the Alfred P. Sloan Foundation, and the Research Corporation for Science Advancement through Cottrell Scholar Award No. 28284. N.S. acknowledges the support from NASA (grant No. 80NSSC22K0332), NASA FINESST (grant No. 80NSSC22K1597), a Columbia University Dean\u2019s fellowship, and a grant from the Simons Foundation. A.E.R. acknowledges support provided by the NSF through CAREER award 2235277 and NASA through EPSCoR grant No. 80NSSC20M0231. B.M. acknowledges financial support from the State Agency for Research of the Spanish Ministry of Science and Innovation under grant PID2019-105510GB-C31/AEI/10.13039/501100011033 and through the Unit of Excellence Mar\u00EDa de Maeztu 2020\u20132023 award to the Institute of Cosmos Sciences (CEX2019-000918-M). The Berger Time-Domain Group at Harvard is supported by NSF and NASA grants.
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science