Ionised gas structure of 100 kpc in an over-dense region of the galaxy group COSMOS-Gr30 at z ~ 0.7

Abstract

We report the discovery of a 10^4 kpc^2 gaseous structure detected in [OII] in an over-dense region of the COSMOS-Gr30 galaxy group at z~0.725 thanks to deep MUSE Guaranteed Time Observations. We estimate the total amount of diffuse ionised gas to be of the order of (~5+-3)x10^10 Msun and explore its physical properties to understand its origin and the source(s) of the ionisation. The MUSE data allow the identification of a dozen of group members embedded in this structure from emission and absorption lines. We extracted spectra from small apertures defined for both the diffuse ionised gas and the galaxies. We investigated the kinematics and ionisation properties of the various galaxies and extended gas regions thanks to line diagnostics (R23, O32 and [OIII]/Hβ) available within the MUSE wavelength range. We compared these diagnostics to photo-ionisation models and shock models. The structure is divided in two kinematically distinct sub-structures. The most extended sub-structure of ionised gas is likely rotating around a massive galaxy and displays filamentary patterns linking some galaxies. The second sub-structure links another massive galaxy hosting an Active Galactic Nucleus to a low mass galaxy but also extends orthogonally to the AGN host disk over ~35 kpc. This extent is likely ionised by the AGN itself. The location of small diffuse regions in the R23 vs. O32 diagram is compatible with photo-ionisation. However, the location of three of these regions in this diagram (low O32, high R23) can also be explained by shocks, which is supported by their large velocity dispersions. One edge-on galaxy shares the same properties and may be a source of shocks. Whatever the hypothesis, the extended gas seems to be non primordial. We favour a scenario where the gas has been extracted from galaxies by tidal forces and AGN triggered by interactions between at least the two sub-structures.

21 pages, 12 figures, 3 tables, accepted for publication in A&A (27 October 2017)

References in corpus (32)

• The Host Galaxies and Classification of Active Galactic Nuclei
• Mass and environment as drivers of galaxy evolution in SDSS and zCOSMOS and the origin of the Schechter function
• The Cosmic Evolution Survey (COSMOS) -- Overview
• Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory
• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• Heating Hot Atmospheres with Active Galactic Nuclei
• COSMOS Photometric Redshifts with 30-bands for 2-deg2
• An ultra-deep near-infrared spectrum of a compact quiescent galaxy at z=2.2
• The MAPPINGS III Library of Fast Radiative Shock Models
• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• The MUSE Hubble Ultra Deep Field Survey: I. Survey description, data reduction and source detection
• Quasar Quartet Embedded in Giant Nebula Reveals Rare Massive Structure in Distant Universe
• The MUSE 3D view of the Hubble Deep Field South
• The COS-Halos Survey: Origins of the Highly Ionized Circumgalactic Medium of Star-Forming Galaxies
• The MUSE Hubble Ultra Deep Field Survey: II. Spectroscopic redshifts and comparisons to color selections of high-redshift galaxies
• The VIMOS VLT Deep Survey: The build-up of the colour-density relation
• Magnetic support of the optical emission line filaments in NGC 1275
• Powerful High Velocity-Dispersion Molecular Hydrogen Associated with an Intergalactic Shock Wave in Stephan's Quintet
• Collisional heating as the origin of filament emission in galaxy clusters
• The Spiderweb galaxy: a forming massive cluster galaxy at z~2
• The zCOSMOS 20k Group Catalog
• Molecular Gas in the Halo Fuels the Growth of a Massive Cluster Galaxy at High Redshift
• On the HI content, dust-to-gas ratio and nature of MgII absorbers
• The MUSE Hubble Ultra Deep Field Survey VIII : Extended Lyman-alpha haloes around high-redshift star-forming galaxies
• Diffuse UV light associated with the Spiderweb Galaxy: evidence for in-situ star formation outside galaxies
• Integral field spectroscopy of ionized and molecular gas in cool cluster cores: evidence for cold feedback?
• The MUSE Hubble Ultra Deep Field Survey: V. Spatially resolved stellar kinematics of galaxies at redshift $0.2\lesssim z\lesssim 0.8$
• A study of the ionized gas in Stephan's Quintet from integral field spectroscopy observations
• MUSE-inspired view of the quasar Q2059-360, its Lyman alpha blob, and its neighborhood
• SDSS IV MaNGA: Discovery of an $H_{\alpha }$ blob associated with a dry galaxy pair -- ejected gas or a `dark' galaxy candidate?
• SDSS-IV MaNGA: A serendipitous observation of a potential gas accretion event
• MOSFIRE and LDSS3 Spectroscopy for an [OII] Blob at z=1.18: Gas Outflow and Energy Source

Cited by in corpus (24)

• A 100-kiloparsec wind feeding the circumgalactic medium of a massive compact galaxy
• A Complete Census of Circumgalactic MgII at Redshift z<~ 0.5
• MusE GAs FLOw and Wind (MEGAFLOW) VIII. Discovery of a MgII emission halo probed by a quasar sightline
• Exploring HeII$\lambda$1640 emission line properties at $z\sim 2-4$
• A Giant Intragroup Nebula Hosting a Damped Lya Absorber at z=0.313
• The MUSE eXtremely Deep Field: Individual detections of Lyα haloes around rest-frame UV-selected galaxies at z~2.9-4.4
• Metal line emission from galaxy haloes at z~1
• The MUSE Extremely Deep Field: a first panoramic view of an Mg II emitting intragroup medium
• Cool circumgalactic gas of passive galaxies from cosmological inflow
• Physical Properties of Massive Compact Starburst Galaxies with Extreme Outflows
• MUSE-ALMA Haloes VIII: Statistical Study of Circumgalactic Medium Gas
• Directly tracing cool filamentary accretion over >100 kpc into the interstellar medium of a quasar host at z=1
• MUSE-ALMA Haloes VII: Survey Science Goals & Design, Data Processing and Final Catalogues
• Discovery and origins of giant optical nebulae surrounding quasar PKS 0454-22
• The Tully-Fisher relation in dense groups at $z\sim 0.7$ in the MAGIC survey
• MUSE-ALMA Halos XI: Gas flows in the circumgalactic medium
• MAGIC: Muse gAlaxy Groups In Cosmos -- A survey to probe the impact of environment on galaxy evolution over the last 8 Gyr
• Scaling relations of z~0.25-1.5 galaxies in various environments from the morpho-kinematic analysis of the MAGIC sample
• Outlying H$\alpha$ emitters in SDSS IV MaNGA
• The leakage of Lyman-continuum photons from a major merger at $z\sim 1$
• Metal line emission around z<1 galaxies
• Origin of Weak MgII and Higher Ionization Absorption Lines in an Outflow from an Intermediate-Redshift Dwarf Satellite Galaxy
• Modelling gas around galaxy pairs and groups using the Q0107 quasar triplet
• The BLOBs: Enigmatic Diffuse Ionized Gas Structures in a Cluster of Galaxies near Cosmic Noon