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Candidate LBV stars in galaxy NGC 7793 found via HST photometry + MUSE spectroscopy

Wofford, Aida and Ramírez, Vanesa and Lee, Janice C. and Thilker, David A. and Della Bruna, Lorenza and Adamo, Angela and Van Dyk, Schuyler D. and Herrero, Artemio and Kim, Hwihyun and Aloisi, Alessandra and Calzetti, Daniela and Chandar, Rupali and Dale, Daniel A. and de Mink, Selma E. and Gallagher, John S. and Gouliermis, Dimitrios A. and Grasha, Kathryn and Grebel, Eva K. and Sacchi, E. and Smith, Linda J. and Ubeda, Leonardo and Walterbos, Rene A. M. and Hannon, Stephen and Messa, Matteo (2020) Candidate LBV stars in galaxy NGC 7793 found via HST photometry + MUSE spectroscopy. Monthly Notices of the Royal Astronomical Society, 493 (2). pp. 2410-2428. ISSN 0035-8711. doi:10.1093/mnras/staa290.

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Only about 19 Galactic and 25 extragalactic bonafide luminous blue variables (LBVs) are known to date. This incomplete census prevents our understanding of this crucial phase of massive star evolution which leads to the formation of heavy binary black holes via the classical channel. With large samples of LBVs one could better determine the duration and maximum stellar luminosity which characterize this phase. We search for candidate LBVs (cLBVs) in a new galaxy, NGC 7793. For this purpose, we combine high spatial resolution images from two Hubble Space Telescope (HST) programs with optical spectroscopy from the Multi Unit Spectroscopic Explorer (MUSE). By combining PSF-fitting photometry measured on F547M, F657N, and F814W images, with restrictions on point-like appearance (at HST resolution) and H α luminosity, we find 100 potential cLBVs, 36 of which fall in the MUSE fields. Five of the latter 36 sources are promising cLBVs which have MV ≤ −7 and a combination of: H α with a P-Cygni profile; no [O I]λ6300 emission; weak or no [O III]λ5007 emission; large [N II]/H α relative to H II regions; and [S II]λ6716/[S II]λ6731∼1⁠. It is not clear if these five cLBVs are isolated from O-type stars, which would favour the binary formation scenario of LBVs. Our study, which approximately covers one fourth of the optical disc of NGC 7793, demonstrates how by combining the above HST surveys with multi-object spectroscopy from 8-m class telescopes, one can efficiently find large samples of cLBVs in nearby galaxies.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ramírez, Vanesa0000-0002-2464-2273
Lee, Janice C.0000-0002-2278-9407
Thilker, David A.0000-0002-8528-7340
Adamo, Angela0000-0002-8192-8091
Van Dyk, Schuyler D.0000-0001-9038-9950
Kim, Hwihyun0000-0003-4770-688X
Aloisi, Alessandra0000-0003-4137-882X
Calzetti, Daniela0000-0002-5189-8004
Dale, Daniel A.0000-0002-5782-9093
Gallagher, John S.0000-0001-8608-0408
Gouliermis, Dimitrios A.0000-0002-2763-0075
Grasha, Kathryn0000-0002-3247-5321
Grebel, Eva K.0000-0002-1891-3794
Sacchi, E.0000-0001-5618-0109
Smith, Linda J.0000-0002-0806-168X
Hannon, Stephen0000-0001-9628-8958
Messa, Matteo0000-0003-1427-2456
Additional Information:© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2020 January 24. Received 2020 January 10; in original form 2019 November 29. Based on observations made with the NASA/ESA HubbleSpace Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universitiesfor Research in Astronomy, under NASA Contract NAS5-26555. These observations are associated with Program 13364. Support for Program 13364 was provided by NASA through a grant from the Space Telescope Science Institute. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet PropulsionLaboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. AW and VR acknowledge funding from Universidad Nacional Autónoma de México (Proyectos de Investigación e Innovación Tecnológica, PAPIIT IA105018). SdM acknowledges funding from the European Research Council (ERC) grant no. 715063, and the Netherlands Organisation for Scientific Research (NWO) through a VIDI grant no. 639.042.728. DAG acknowledges support by the German Aerospace Center (DLR) and the Federal Ministry for Economic Affairs and Energy (BMWi) through program 50OR1801 ‘MYSST: Mapping Young Stars in Space and Time’. We thank the referee for his careful revision of the manuscript.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Universidad Nacional Autónoma de México (UNAM)PAPIIT IA10501
European Research Council (ERC)715063
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)639.042.728
Deutsches Zentrum für Luft- und Raumfahrt (DLR)UNSPECIFIED
Bundesministerium für Wirtschaft und Energie (BMWi)50OR1801
Subject Keywords:catalogues, stars: massive, stars: variables: S Doradus, galaxies: individual: NGC 7793
Issue or Number:2
Record Number:CaltechAUTHORS:20200430-151241795
Persistent URL:
Official Citation:Aida Wofford, Vanesa Ramírez, Janice C Lee, David A Thilker, Lorenza Della Bruna, Angela Adamo, Schuyler D Van Dyk, Artemio Herrero, Hwihyun Kim, Alessandra Aloisi, Daniela Calzetti, Rupali Chandar, Daniel A Dale, Selma E de Mink, John S Gallagher, Dimitrios A Gouliermis, Kathryn Grasha, Eva K Grebel, E Sacchi, Linda J Smith, Leonardo Úbeda, Rene A M Walterbos, Stephen Hannon, Matteo Messa, Candidate LBV stars in galaxy NGC 7793 found via HST photometry + MUSE spectroscopy, Monthly Notices of the Royal Astronomical Society, Volume 493, Issue 2, April 2020, Pages 2410–2428,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:102952
Deposited By: George Porter
Deposited On:01 May 2020 18:23
Last Modified:16 Nov 2021 18:17

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