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Imaging Spectroscopy of CME-associated Solar Radio Bursts using OVRO-LWA

Chhabra, Sherry and Gary, Dale E. and Hallinan, Gregg and Anderson, Marin M. and Chen, Bin and Greenhill, Lincoln J. and Price, Danny C. (2021) Imaging Spectroscopy of CME-associated Solar Radio Bursts using OVRO-LWA. Astrophysical Journal, 906 (2). Art. No. 132. ISSN 1538-4357. https://resolver.caltech.edu/CaltechAUTHORS:20210119-143307882

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Abstract

We present the first results of a solar radio event observed with the Owens Valley Radio Observatory Long Wavelength Array at metric wavelengths. We examine a complex event consisting of multiple radio sources/bursts associated with a fast coronal mass ejection (CME) and an M2.1 GOES soft X-ray flare from 2015 September 20. Images of 9 s cadence are used to analyze the event over a 120 minute period, and solar emission is observed out to a distance of ≈3.5 R -⊙, with an instantaneous bandwidth covering 22 MHz within the frequency range of 40–70 MHz. We present our results from the investigation of the radio event, focusing particularly on one burst source that exhibits outward motion, which we classify as a moving type IV burst. We image the event at multiple frequencies and use the source centroids to obtain the velocity for the outward motion. Spatial and temporal comparison with observations of the CME in white light from the C2 coronagraph of the Large Angle and Spectrometric COronagraph, indicates an association of the outward motion with the core of the CME. By performing graduated-cylindrical-shell reconstruction of the CME, we constrain the density in the volume. The electron plasma frequency obtained from the density estimates do not allow us to completely dismiss plasma emission as the underlying mechanism. However, based on source height and smoothness of the emission in frequency and time, we argue that gyrosynchrotron is the more plausible mechanism. We use gyrosynchrotron spectral-fitting techniques to estimate the evolving physical conditions during the outward motion of this burst source.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3847/1538-4357/abc94bDOIArticle
https://arxiv.org/abs/2011.06073arXivDiscussion Paper
ORCID:
AuthorORCID
Chhabra, Sherry0000-0001-7754-0804
Gary, Dale E.0000-0003-2520-8396
Hallinan, Gregg0000-0002-7083-4049
Anderson, Marin M.0000-0003-2238-2698
Chen, Bin0000-0002-0660-3350
Greenhill, Lincoln J.0000-0003-4912-5974
Price, Danny C.0000-0003-2783-1608
Alternate Title:Imaging Spectroscopy of CME-Associated Solar Radio Bursts
Additional Information:© 2021. The American Astronomical Society. Received 2020 July 1; revised 2020 November 6; accepted 2020 November 9; published 2021 January 18. S.C. thanks Robin Colaninno and Angelos Vourlidas for their helpful discussions in understanding the CME morphology. S.C. also thanks Camilia Scolini for sharing her insights on the GCS reconstruction method. This work was supported in part by the NSF grants AST-1615807, AGS-1654382, and AST-19010354 and by NASA grants 80NSSC18K1128 and 80NSSC17K0660 to New Jersey Institute of Technology. G.H. acknowledges support by NSF grants AST-1654815, AST-1828784. L.G. acknowledges support by NSF grants PHY-0835713, OIA-1125087, AST-1106059 and AST-1616709. The CME catalog is generated and maintained at the CDAW Data Center by NASA and The Catholic University of America in cooperation with the Naval Research Laboratory. SOHO is a project of international cooperation between ESA and NASA.
Group:Astronomy Department
Funders:
Funding AgencyGrant Number
NSFAST-1615807
NSFAGS-1654382
NSFAST-19010354
NAASA80NSSC18K1128
NASA80NSSC17K0660
NSFAST-1654815
NSFAST-1828784
NSFPHY-0835713
NSFOIA-1125087
NSFAST-1106059
NSFAST-1616709
Subject Keywords:Radio continuum emission ; Solar radio emission ; Solar coronal mass ejections ; Solar radio flares
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Radio continuum emission (1340); Solar radio emission (1522); Solar coronal mass ejections (310); Solar radio flares (1342)
Record Number:CaltechAUTHORS:20210119-143307882
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210119-143307882
Official Citation:Sherry Chhabra et al 2021 ApJ 906 132
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107561
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:19 Jan 2021 23:01
Last Modified:03 Feb 2021 22:22

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