The ALMA Fornax Cluster Survey I: Stirring and stripping of the molecular gas in cluster galaxies

Nikki Zabel*, Timothy A. Davis, Matthew W. L. Smith, Natasha Maddox, George J. Bendo, Reynier Peletier, Enrichetta Iodice, Aku Venhola, Maarten Baes, Jonathan I. Davies, Ilse de Looze, Haley Gomez, Marco Grossi, Jeffrey D. P. Kenney, Paolo Serra, Freeke van de Voort, Catherine Vlahakis, Lisa M. Young

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

We present the first results of the ALMA Fornax Cluster Survey: a complete ALMA survey of all members of the Fornax galaxy cluster that were detected in H I or in the far-infrared with Herschel. The sample consists of a wide variety of galaxy types, ranging from giant ellipticals to spiral galaxies and dwarfs, located in all (projected) areas of the cluster. It spans a mass range of 10̃8.5-11 M. The CO(1-0) line was targeted as a tracer for the cold molecular gas, along with the associated 3 mm continuum. CO was detected in 15 of the 30 galaxies observed. All 8 detected galaxies with stellar masses below 3 × 109 M have disturbed molecular gas reservoirs; only 7 galaxies are regular/undisturbed. This implies that Fornax is still a very active environment, having a significant impact on its members. Both detections and non-detections occur at all projected locations in the cluster. Based on visual inspection, and the detection of molecular gas tails in alignment with the direction of the cluster centre, in some cases ram pressure stripping is a possible candidate for disturbing the molecular gas morphologies and kinematics. Derived gas fractions in almost all galaxies are lower than expected for field objects with the same mass, especially for the galaxies with disturbed molecular gas, with differences of sometimes more than an order of magnitude. The detection of these disturbed molecular gas reservoirs reveals the importance of the cluster environment for even the tightly bound molecular gas phase.
Original languageEnglish
Pages (from-to)2251-2268
Number of pages18
JournalMonthly Notices of the Royal Astronomical Society
Volume483
Issue number2
DOIs
Publication statusPublished - 1-Feb-2019

Keywords

  • galaxies: clusters: general
  • galaxies: clusters: individual: Fornax
  • galaxies: evolution
  • galaxies: ISM
  • HERSCHEL VIRGO CLUSTER
  • DIGITAL SKY SURVEY
  • DWARF GALAXIES
  • STAR-FORMATION
  • RAM-PRESSURE
  • ATLAS(3D) PROJECT
  • NEUTRAL HYDROGEN
  • REDSHIFT SURVEY
  • HI CONTENT
  • NGC 1427A

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