Disentangling the multi-phase circumgalactic medium shared between a dwarf and a massive star-forming galaxy at z~0.4

Abstract

The multi-phase circumgalactic medium (CGM) arises within the complex environment around a galaxy, or collection of galaxies, and possibly originates from a wide range of physical mechanisms. In this paper, we attempt to disentangle the origins of these multi-phase structures and present a detailed analysis of the quasar field Q0122-003 field using Keck/KCWI galaxy observations and HST/COS spectra probing the CGM. Our re-analysis of this field shows that there are two galaxies associated with the absorption. We have discovered a dwarf galaxy, G_27kpc ($M_{\star }=10^{8.7}$ M${}_{\odot }$), at z=0.39863 that is 27 kpc from the quasar sightline. G_27kpc is only +21 km/s from a more massive ($M_{\star }=10^{10.5}$ M${}_{\odot }$) star-forming galaxy, G_163kpc, at an impact parameter of 163 kpc. While G_163kpc is actively forming stars (SFR=6.9 M${}_{\odot }$ yr${}^{-1}$), G_27kpc has a low star-formation rate (SFR=$0.08\pm 0.03$ M${}_{\odot }$ yr${}^{-1}$) and star formation surface density (${\Sigma }_{SFR}=0.006$ M${}_{\odot }$ kpc${}^{-2}$ yr${}^{-1}$), implying no active outflows. By comparing galaxy SFRs, kinematics, masses and distances from the quasar sightline to the absorption kinematics, column densities and metallicities, we have inferred the following: (1) Part of the low-ionization phase has a metallicity and kinematics consistent with being accreted onto G_27kpc. (2) The remainder of the low ionization phase has metallicities and kinematics consistent with being intragroup gas being transferred from G_27kpc to G_163kpc. (3) The high ionization phase is consistent with being produced solely by outflows originating from the massive halo of G_163kpc. Our results demonstrate the complex nature of the multi-phase CGM, especially around galaxy groups, and that detailed case-by-case studies are critical for disentangling its origins.

13 pages, 4 figures, accepted for publication in MNRAS 2020 November 10

References in corpus (28)

• The Circumgalactic Medium
• An ultra-deep near-infrared spectrum of a compact quiescent galaxy at z=2.2
• Ubiquitous outflows in DEEP2 spectra of star-forming galaxies at z=1.4
• Mass, Metal, and Energy Feedback in Cosmological Simulations
• The 2013 Release of Cloudy
• Characterizing the Circumgalactic Medium of Nearby Galaxies with HST/COS and HST/STIS Absorption-Line Spectroscopy
• The COS-Dwarfs Survey: The Carbon Reservoir Around sub-L* Galaxies
• Halo Gas Cross Sections And Covering Fractions of MgII Absorption Selected Galaxies
• MusE GAs FLOw and Wind (MEGAFLOW) II. A study of gas accretion around $z\approx 1$ star-forming galaxies with background quasars
• Quasars Probing Galaxies: I. Signatures of Gas Accretion at Redshift Approximately 0.2
• The large and small scale properties of the intergalactic gas in the Slug Ly-alpha nebula revealed by MUSE HeII emission observations
• Neutral Hydrogen Clouds in the M81/M82 Group
• New Perspective on Galaxy Outflows From the First Detection of Both Intrinsic and Traverse Metal-Line Absorption
• The properties of the cool circumgalactic gas probed with the SDSS, WISE and GALEX surveys
• Multi-phase Circum-Galactic Medium probed with MUSE and ALMA
• Tracing the Cosmic Metal Evolution in the Low-Redshift Intergalactic Medium
• The VLT SINFONI Mg ii Program for Line Emitters (SIMPLE) II: background quasars probing z $\sim$ 1 galactic winds
• Low-metallicity Absorbers Account for Half of the Dense Circumgalactic Gas at z < 1
• Nature of the Absorbing Gas associated with a Galaxy Group at z~0.4
• Galaxy mergers moulding the circum-galactic medium - I. The impact of a major merger
• Slicing the cool circumgalactic medium along the major-axis of a star-forming galaxy at $z=0.7$
• Observational signatures of a warped disk associated with cold-flow accretion
• MUSE-ALMA Halos V: Physical properties and environment of z < 1.4 HI quasar absorbers
• A Giant Intragroup Nebula Hosting a Damped Lya Absorber at z=0.313
• The Highly Ionized Circumgalactic Medium is Kinematically Uniform Around Galaxies
• The Impact of the Group Environment on the OVI Circumgalactic Medium
• Multi-object spectroscopy of the field surrounding PKS 2126-158: Discovery of a z=0.66 galaxy group
• Low Mass Group Environments have no Substantial Impact on the Circumgalactic Medium Metallicity

Cited by in corpus (1)

• Evidence for galaxy quenching in the green valley caused by a lack of a circumgalactic medium