Linking Mg II and [O II] spatial distribution to ionizing photon escape in confirmed LyC leakers and non-leakers

Abstract

The geometry of the neutral gas in and around galaxies is a key regulator of the escape of ionizing photons. We present the first statistical study aiming at linking the neutral and ionized gas distributions to the Lyman continuum (LyC) escape fraction (fesc(LyC)) in a sample of 22 confirmed LyC leakers and non-leakers at z~0.35 using the Keck Cosmic Web Imager (Keck/KCWI) and the Low Resolution Spectrograph 2 (HET/LRS2). Our integral field unit data enable the detection of neutral and low-ionization gas, as traced by Mg II, and ionized gas, as traced by [O II], extending beyond the stellar continuum for 7 and 10 objects, respectively. All but one object with extended Mg II emission also shows extended [O II] emission; in this case, Mg II emission is always more extended than [O II] by a factor 1.3 on average. Most of the galaxies with extended emission are non or weak LyC leakers (fesc(LyC) < 5%), but we find a large diversity of neutral gas configurations around these weakly LyC-emitting galaxies. Conversely, the strongest leakers (fesc(LyC) > 10%) appear uniformly compact in both Mg II and [O II] with exponential scale lengths <1 kpc. We also find a trend between fesc(LyC) and the spatial offsets of the nebular gas and the stellar continuum emission. Moreover, we find significant anti-correlations between the spatial extent of the neutral gas and the [O III]/[O II] ratio, and H$\beta$ equivalent width, as well as positive correlations with metallicity and UV size, suggesting that galaxies with more compact neutral gas sizes are more highly ionized. The observations suggest that strong LyC emitters do not have extended neutral gas halos and ionizing photons may be emitted in many directions. Combined with high ionization diagnostics, we propose the Mg II, and potentially [O II], spatial compactness are indirect indicators of LyC emitting galaxies at high-redshift.

31 pages, 24 figures, 4 tables, submitted to A&A

References in corpus (63)

• The Circumgalactic Medium
• Cosmic Reionization and Early Star-Forming Galaxies: A Joint Analysis of New Constraints from Planck and Hubble Space Telescope
• The MUSE second-generation VLT instrument
• Two Remarkably Luminous Galaxy Candidates at $z\approx 10-12$ Revealed by JWST
• JADES NIRSpec Spectroscopy of GN-z11: Lyman-$\alpha$ emission and possible enhanced nitrogen abundance in a $z=10.60$ luminous galaxy
• Conditions for Reionizing the Universe with A Low Galaxy Ionizing Photon Escape Fraction
• Hydrogen reionisation ends by $z=5.3$: Lyman-$\alpha$ optical depth measured by the XQR-30 sample
• Identification and properties of intense star-forming galaxies at redshifts z>10
• Galaxy Formation and Reionization: Key Unknowns and Expected Breakthroughs by the James Webb Space Telescope
• Lyman-alpha spectral properties of five newly discovered Lyman continuum emitters
• A Local Clue to the Reionization of the Universe
• The Low-Redshift Lyman Continuum Survey I: New, Diverse Local Lyman-Continuum Emitters
• JADES: Probing interstellar medium conditions at $z\sim 5.5-9.5$ with ultra-deep JWST/NIRSpec spectroscopy
• The Low-Redshift Lyman Continuum Survey II: New Insights into LyC Diagnostics
• The HETDEX Instrumentation: Hobby-Eberly Telescope Wide Field Upgrade and VIRUS
• New perspectives on strong z=0.5 MgII absorbers: are halo-mass and equivalent width anti-correlated?
• Lyman continuum leakage from low-mass galaxies with Mstar < 1.E8 Msun
• UV Luminosity Density Results at z>8 from the First JWST/NIRCam Fields: Limitations of Early Data Sets and the Need for Spectroscopy
• The Lyman alpha Reference Sample: Extended Lyman alpha Halos Produced at Low Dust Content
• MusE GAs FLOw and Wind (MEGAFLOW) II. A study of gas accretion around $z\approx 1$ star-forming galaxies with background quasars
• The Lyman-alpha Reference Sample: I. Survey outline and first results for Markarian 259
• The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) Survey Design, Reductions, and Detections
• Quasars Probing Galaxies: I. Signatures of Gas Accretion at Redshift Approximately 0.2
• The origin of the escape of Lyman alpha and ionizing photons in Lyman Continuum Emitters
• A 100-kiloparsec wind feeding the circumgalactic medium of a massive compact galaxy
• EPOCHS VI: The Size and Shape Evolution of Galaxies since z ~ 8 with JWST Observations
• MUSE Analysis of Gas around Galaxies (MAGG) -- II: Metal-enriched halo gas around z~1 galaxies
• The SINFONI MgII Program for Line Emitters (SIMPLE): Discovering starbursts near QSO sight-lines
• Optically-Thin Spatially-Resolved Mg II Emission Maps the Escape of Ionizing Photons
• The Low-Redshift Lyman Continuum Survey. Unveiling the ISM properties of low-$z$ Lyman continuum emitters
• Closing in on the sources of cosmic reionization: first results from the GLASS-JWST program
• Do galaxies that leak ionizing photons have extreme outflows?
• Morphologies of Galaxies at $z\gtrsim 9$ Uncovered by JWST/NIRCam Imaging: Cosmic Size Evolution and an Identification of an Extremely Compact Bright Galaxy at $z\sim 12$
• Early results from GLASS-JWST. V: the first rest-frame optical size-luminosity relation of galaxies at $z>7$
• MusE GAs FLOw and Wind (MEGAFLOW) VIII. Discovery of a MgII emission halo probed by a quasar sightline
• Kinematics and Optical Depth in the Green Peas: Suppressed Superwinds in Candidate LyC Emitters
• Nature of the Absorbing Gas associated with a Galaxy Group at z~0.4
• GA-NIFS: The core of an extremely massive proto-cluster at the Epoch of Reionization probed with JWST/NIRSpec
• Quantifying Distributions of Lyman Continuum Escape Fraction
• An extreme blue nugget, UV-bright starburst at z=3.613 with ninety per cent of Lyman continuum photon escape
• MIDIS: Strong (Hb + [OIII]) and Ha emitters at redshift $z\simeq 7-8$ unveiled with JWST/NIRCam and MIRI imaging in the Hubble eXtreme Deep Field (XDF)
• Lyman-$\alpha$ as a tracer of cosmic reionisation in the SPHINX radiation-hydrodynamics cosmological simulation
• UV absorption lines and their potential for tracing the Lyman continuum escape fraction
• Observational signatures of a warped disk associated with cold-flow accretion
• The UV-brightest Lyman continuum emitting star-forming galaxy
• New Methods for Identifying Lyman Continuum Leakers and Reionization-Epoch Analogues
• The cold circumgalactic medium in emission: MgII halos in TNG50
• Tracing Lyman-alpha and Lyman Continuum Escape in Galaxies with Mg II Emission
• Ubiquitous broad-line emission and the relation between ionized gas outflows and Lyman continuum escape in Green Pea galaxies
• Bipolar Outflows out to 10~kpc for Massive Galaxies at Redshift $z\approx 1$
• The MUSE Hubble Ultra Deep Field Survey: VII. FeII* Emission in Star-Forming Galaxies
• Lyman alpha and Lyman continuum emission of MgII-selected star-forming galaxies
• The Lensed Lyman-Alpha MUSE Arcs Sample (LLAMAS) : I. Characterisation of extended Lyman-alpha haloes and spatial offsets
• Metal line emission from galaxy haloes at z~1
• The Geometry of Cold, Metal-Enriched Gas Around Galaxies at $z\sim 1.2$
• The MUSE Extremely Deep Field: a first panoramic view of an Mg II emitting intragroup medium
• The space density of ultra-luminous QSOs at the end of reionization epoch by the QUBRICS Survey and the AGN contribution to the hydrogen ionizing background
• The Low-Redshift Lyman Continuum Survey: Optically Thin and Thick Mg II Lines as Probes of Lyman Continuum Escape
• The Effect of Bi-conical Outflows on Ly$\alpha$ Escape From Green Peas
• The Atomic Gas Mass of Green Pea Galaxies
• A 30 kpc Spatially Extended Clumpy and Asymmetric Galactic Outflow at z $\sim$ 1.7
• On the evolution of the size of Lyman alpha halos across cosmic time: no change in the circumgalactic gas distribution when probed by line emission
• The Lyman Alpha Reference Sample XII: Morphology of extended Lyman alpha emission in star-forming galaxies

Cited by in corpus (9)

• Anatomy of an ionized bubble: NIRCam grism spectroscopy of the $z=6.6$ double-peaked Lyman-$\alpha$ emitter COLA1 and its environment
• A galactic outflow traced by its extended Mg II emission out to a $\sim 30$ kpc radius in the Hubble Ultra Deep Field with MUSE
• The Lyman-alpha and Continuum Origins Survey. I. Survey description and Ly$\alpha$ imaging
• The Lyman-alpha and Continuum Origins Survey II: the connection between the escape of ionizing radiation and Lyman-alpha halos in star-forming galaxies
• Ionizing Radiation Escape from Low-Redshift Galaxies and Its Connection to Cosmic Reionization
• A public grid of radiative transfer simulations for Lyman-alpha and metal lines in idealised galactic outflows
• Metal line emission around z<1 galaxies
• The Ly$\alpha$ and Continuum Origins Survey. III. Investigating the Link between Galaxy Morphology, Merger Properties and LyC Escape
• The 21cm-galaxy cross-correlation: Realistic forecast for 21cm signal detection and reionisation constraints