Rennie, Thomas J. and Harper, Stuart E. and Dickinson, Clive and Philip, Liju and Cleary, Kieran A. and Bond, Richard J. and Borowska, Jowita and Breysse, Patrick C. and Catha, Morgan and Cepeda-Arroita, Roke and Chung, Dongwoo T. and Church, Sarah E. and Dunne, Delaney A. and Eriksen, Hans Kristian and Foss, Marie Kristine and Gaier, Todd and Gundersen, Joshua Ott and Harris, Andrew I. and Hensley, Brandon and Hobbs, Richard and Ihle, Håvard T. and Lamb, James W. and Lawrence, Charles R. and Lunde, Jonas G. S. and Paladini, Roberta and Pearson, Timothy J. and Rasmussen, Maren and Readhead, Anthony C. S. and Stutzer, Nils-Ole and Watts, Duncan J. and Wehus, Ingunn Kathrine and Woody, David P. (2022) COMAP Early Science. VI. A First Look at the COMAP Galactic Plane Survey. Astrophysical Journal, 933 (2). Art. No. 187. ISSN 0004-637X. doi:10.3847/1538-4357/ac63c8. https://resolver.caltech.edu/CaltechAUTHORS:20220725-157003000
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Abstract
We present early results from the CO Mapping Array Project (COMAP) Galactic Plane Survey conducted between 2019 June and 2021 April, spanning 20° ℓ b∣ ii regions and supernova remnants (SNRs). Using low- and high-frequency surveys to constrain free–free and thermal dust emission contributions, we find evidence of excess flux density at 30 GHz in six regions, which we interpret as anomalous microwave emission. Furthermore we model ultracompact H ii contributions using data from the 5 GHz CORNISH catalog and reject these as the cause of the 30 GHz excess. Six known SNRs are detected at 30 GHz, and we measure spectral indices consistent with the literature or show evidence of steepening. The flux density of the SNR W44 at 30 GHz is consistent with a power-law extrapolation from lower frequencies with no indication of spectral steepening in contrast with recent results from the Sardinia Radio Telescope. We also extract five hydrogen radio recombination lines (RRLs) to map the warm ionized gas, which can be used to estimate electron temperatures or to constrain continuum free–free emission. The full COMAP Galactic Plane Survey, to be released in 2023/2024, will span ℓ ∼ 20°–220° and will be the first large-scale radio continuum and RRL survey at 30 GHz with 4.′5 resolution.
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| Additional Information: | © 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2021 November 19; revised 2022 February 24; accepted 2022 March 6; published 2022 July 13. Focus on Early Science Results from the CO Mapping Array Project (COMAP). This material is based on work supported by the National Science Foundation (NSF) under grant Nos. 1517108, 1517288, 1517598, 1518282, and 1910999, and by the Keck Institute for Space Studies under "The First Billion Years: A Technical Development Program for Spectral Line Observations." D.T.C. is supported by a CITA/Dunlap Institute postdoctoral fellowship. The Dunlap Institute is funded through an endowment established by the David Dunlap family and the University of Toronto. C.D. acknowledges support from an STFC Consolidated Grant (ST/P000649/1). Work at the University of Oslo is supported by the Research Council of Norway through grants 251328 and 274990, and by the European Research Council under the Horizon 2020 Research and Innovation Program (grant agreement No. 819478, Cosmoglobe). J.O.G. acknowledges support from the University of Miami and is grateful to Hugh Medrano for his assistance with cryostat design. S.E.H. acknowledges support from an STFC Consolidated Grant (ST/P000649/1). We thank Isu Ravi for her contributions to the warm electronics and antenna drive characterization. Part of this research was carried out at the Jet Propulsion Laboratory (JPL), California Institute of Technology, under a contract with the National Aeronautics and Space Administration. At JPL, we are grateful to Mary Soria for her assembly work on the amplifier modules and to Jose Velasco, Ezra Long, and Jim Bowen for the use of their amplifier test facilities. We would like to thank Ivayla Kalcheva for discussions on source classification in the CORNISH UCHii survey. We would also like to thank Eugenio Schisano for providing the Hi-GAL maps used to closely examine the sources presented in this work. The scientific color maps roma and romaO (Crameri 2018) are used in this study to prevent visual distortion of the data and exclusion of readers with color-vision deficiencies (Crameri et al. 2020). We thank the anonymous referee, whose comments and suggestions have helped to improve and clarify this manuscript. Facility: CO Mapping Array Project: Pathfinder - Software: Astropy (The Astropy Collaboration et al. 2013,2018), emcee (Foreman-Mackey et al. 2013b), h5py (Collette et al. 2021), healpy (Zonca et al. 2020), Matplotlib (Hunter 2007), NumPy (Harris et al. 2020), SciPy (Virtanen et al. 2020), Source Extractor Python (Bertin & Arnouts 1996; Barbary 2016). | ||||||||||||||||||||||||||||||||||||||||||||||||
| Group: | Astronomy Department, Infrared Processing and Analysis Center (IPAC), Owens Valley Radio Observatory (OVRO), Keck Institute for Space Studies | ||||||||||||||||||||||||||||||||||||||||||||||||
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| Subject Keywords: | Surveys; H II regions; Supernova remnants; Interstellar medium; Milky Way Galaxy; Radio continuum emission | ||||||||||||||||||||||||||||||||||||||||||||||||
| Issue or Number: | 2 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Classification Code: | Unified Astronomy Thesaurus concepts: Surveys (1671); H II regions (694); Supernova remnants (1667); Interstellar medium (847); Milky Way Galaxy (1054); Radio continuum emission (1340) | ||||||||||||||||||||||||||||||||||||||||||||||||
| DOI: | 10.3847/1538-4357/ac63c8 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Record Number: | CaltechAUTHORS:20220725-157003000 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20220725-157003000 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Official Citation: | Thomas J. Rennie et al 2022 ApJ 933 187 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | ||||||||||||||||||||||||||||||||||||||||||||||||
| ID Code: | 115836 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Collection: | CaltechAUTHORS | ||||||||||||||||||||||||||||||||||||||||||||||||
| Deposited By: | George Porter | ||||||||||||||||||||||||||||||||||||||||||||||||
| Deposited On: | 27 Jul 2022 16:33 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Last Modified: | 27 Jul 2022 16:33 |
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