Molecular Gas and Dust in the Brightest Cluster Galaxy of MACS 1931.8-2635

Kevin Fogarty, Marc Postman, Megan Donahue, Yuan Li, Hauyu B. Liu, Helmut Dannerbauer, Italo Balestra, Brenda Frye, Anton Koekemoer, Keiichi Umetsu, Bodo Ziegler

Publications: Contribution to bookContribution to proceedings

Abstract

We present the results of band 3, 6, and 7 ALMA observations obtained of the brightest cluster galaxy (BCG) in MACS 1931.8-2635 over the course of Cycles 4 and 5. MACS 1931 is a massive (M500 = ~5 · 1014 M) cool-core galaxy cluster in the Cluster Lensing and Supernova survey with Hubble (CLASH) with the most actively star-forming BCG in the sample, at ~250 M yr-1. Our observations of the CO (1-0), (3-2) and (4-3) lines reveal a reservoir of molecular gas with a mass of about 2 · 1010 M, on par with the Phoenix cluster, and with a complex dynamical structure. Continuum emission bands 6 and 7 also traces the morphology of cold dust in the BCG. Both the molecular gas and dust morphologies trace ultraviolet knots in the BCG core, along with an Hα-bright tail extending several tens of kpc away to the northwest. We investigate the multiphase nature of material in this system by comparing our observations of CO and dust with measurements of ultraviolet and Hα fluxes previously obtained with CLASH photometry, and discuss the correlations between molecular gas and dust morphologies, and features observed in both radio and X-ray data. We examine possible formation scenarios for dust in the BCG, as well as the implications of the velocity structure, CO line ratios, and limits on the molecular gas velocity dispersion for the mechanism of condensation of the multiphase gas in this system.
Original languageEnglish
Title of host publicationThe 233rd Meeting of the American Astronomical Society
Subtitle of host publicationSeattle, Washington, 6–10 January 2019
Volume233
Publication statusPublished - Jan 2019

Publication series

SeriesAmerican Astronomical Society, AAS Meeting

Austrian Fields of Science 2012

  • 103003 Astronomy
  • 103004 Astrophysics

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