The formation channels of multiphase gas in nearby early-type galaxies

Ryan Eskenasy, Valeria Olivares, Yuanyuan Su, Yuan Li

Research output: Contribution to journalArticlepeer-review


The processes responsible for the assembly of cold and warm gas in early-type galaxies (ETGs) are not well understood. We report on the multiwavelength properties of 15 non-central, nearby (z ≤ 0.008 89) ETGs primarily through Multi-Unit Spectroscopic Explorer (MUSE) and Chandra X-ray observations, to address the origin of their multiphase gas. The MUSE data reveal that 8/15 sources contain warm ionized gas traced by the H α emission line. The morphology of this gas is found to be filamentary in 3/8 sources: NGC 1266, NGC 4374, and NGC 4684, which is similar to that observed in many group and cluster-centred galaxies. All H α filamentary sources have X-ray luminosities exceeding the expected emission from the stellar population, suggesting the presence of diffuse hot gas, which likely cooled to form the cooler phases. The morphologies of the remaining 5/8 sources are rotating gas discs, not as commonly observed in higher mass systems. Chandra X-ray observations (when available) of the ETGs with rotating H α discs indicate that they are nearly void of hot gas. A mixture of stellar mass-loss and external accretion was likely the dominant channel for the cool gas in NGC 4526 and NGC 4710. These ETGs show full kinematic alignment between their stars and gas, and are fast rotators. The H α features within NGC 4191 (clumpy, potentially star-forming ring), NGC 4643, and NGC 5507 (extended structures) along with loosely overlapping stellar and gas populations allow us to attribute external accretion to be the primary formation channel of their cool gas.

Original languageEnglish
Pages (from-to)1317-1332
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Jan 1 2024

Bibliographical note

Publisher Copyright:
© 2023 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.


  • ISM
  • elliptical and lenticular, cD – galaxies
  • galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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