Evidence for late-time feedback from the discovery of multiphase gas in a massive elliptical at z = 0.4

Fakhri S. Zahedy, Hsiao Wen Chen, Erin Boettcher, Michael Rauch, K. Decker French, Ann I. Zabludoff

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


We report the first detection of multiphase gas within a quiescent galaxy beyond z ≈ 0. The observations use the brighter image of doubly lensed QSO HE 0047-1756 to probe the interstellar medium (ISM) of the massive (Mstar ≈ 10 M⊙ 11 ) elliptical lens galaxy at z = 0.408 gal . Using Hubble Space Telescope's Cosmic Origins Spectrograph (COS), we obtain a medium-resolution FUV spectrum of the lensed QSO and identify numerous absorption features from H2 in the lens ISM at projected distance d = 4.6 kpc. The H2 column density is log N(H2)/- cm-2 = - 17.8+ 2 2 0.3 0.1 with a molecular gas fraction of f = 2%-5% H2 , roughly consistent with some local quiescent galaxies. The new COS spectrum also reveals kinematically complex absorption features from highly ionized species O VI and N V with column densities log N(O VI) cm-2 = 15.2 ± 0.1 and log N(N V) cm-2 = 14.6 ± 0.1, among the highest known in external galaxies. Assuming the high-ionization absorption features originate in a transient warm (T∼105 K) phase undergoing radiative cooling from a hot halo surrounding the galaxy, we infer a mass accretion rate of∼0.5-1.5 M⊙ yr-1. The lack of star formation in the lens suggests that the bulk of this flow is returned to the hot halo, implying a heating rate of∼1048 erg yr-1. Continuous heating from evolved stellar populations (primarily SNe Ia but also winds from AGB stars) may suffice to prevent a large accumulation of cold gas in the ISM, even in the absence of strong feedback from an active nucleus.

Original languageEnglish (US)
Article numberabc48d
JournalAstrophysical Journal Letters
Issue number1
StatePublished - Nov 20 2020

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Evidence for late-time feedback from the discovery of multiphase gas in a massive elliptical at z = 0.4'. Together they form a unique fingerprint.

Cite this