On the detectability of visible-wavelength line emission from the local circumgalactic and intergalactic medium

Abstract

We describe a new approach to studying the intergalactic and circumgalactic medium in the local Universe: direct detection through narrow-band imaging of ultra-low surface brightness visible-wavelength line emission. We use the hydrodynamical cosmological simulation EAGLE to investigate the expected brightness of this emission at low redshift ($z$ $\lesssim$ 0.2). H$\alpha$ emission in extended halos (analogous to the extended Ly$\alpha$ halos/blobs detected around galaxies at high redshifts) has a surface brightness of $\gtrsim 700$ photons cm${}^{-2}$ sr${}^{-1}$ s${}^{-1}$ out to $\sim$100 kpc. Mock observations show that the Dragonfly Telephoto Array, equipped with state-of-the-art narrow-band filters, could directly image these structures in exposure times of $\sim$10 hours. H$\alpha$ fluorescence emission from this gas can be used to place strong constraints on the local ultra-violet background, and on gas flows around galaxies. Detecting H$\alpha$ emission from the diffuse intergalactic medium (the "cosmic web") is beyond current capabilities, but would be possible with a hypothetical 1000-lens Dragonfly array.

18 pages, 12 figures. Accepted for publication in ApJ

References in corpus (22)

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• Cold streams in early massive hot haloes as the main mode of galaxy formation
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• The Circumgalactic Medium
• The effect of photo-ionization on the cooling rates of enriched, astrophysical plasmas
• The MUSE second-generation VLT instrument
• A New Calculation of the Ionizing Background Spectrum and the Effects of HeII Reionization
• The COS-Halos Survey: Physical Conditions and Baryonic Mass in the Low-Redshift Circumgalactic Medium
• An H-alpha Imaging Survey of Galaxies in the Local 11 Mpc Volume
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• Characterizing the Circumgalactic Medium of Nearby Galaxies with HST/COS and HST/STIS Absorption-Line Spectroscopy
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• Through Thick and Thin - HI Absorption in Cosmological Simulations
• Inspiraling Halo Accretion Mapped in Lyman-$\alpha$ Emission around a $z\sim 3$ Quasar
• Morphological evolution of galaxies from ultradeep HST WFC3 imaging: the Hubble sequence at z~2
• A measurement of the z = 0 UV background from H$\alpha$ fluorescence
• Halpha Imaging of the Herschel Reference Survey. The star formation properties of a volume-limited, K-band-selected sample of nearby late-type galaxies
• Numerical simulations of the Warm-Hot Intergalactic Medium
• Tracing dense and diffuse neutral hydrogen in the halo of the Milky Way

Cited by in corpus (10)

• The cold circumgalactic medium in emission: MgII halos in TNG50
• Metal line emission from galaxy haloes at z~1
• Revealing the physical properties of gas accreting to haloes in the EAGLE simulations
• A giant shell of ionized gas discovered near M82 with the Dragonfly Spectral Line Mapper pathfinder
• A Nascent Tidal Dwarf Galaxy Forming within the Northern HI Streamer of M82
• 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
• Absorption-based Circumgalactic Medium Line Emission Estimates
• The pathfinder Dragonfly Spectral Line Mapper: Pushing the limits for ultra-low surface brightness spectroscopy
• Imaging reionization's last phases with I-front Lyman-$\alpha$ emissions
• Wide-field ultra-narrow-bandpass imaging with the Dragonfly Telephoto Array