%0 Generic %1 lokhorst2019detectability %A Lokhorst, Deborah %A Abraham, Roberto %A van Dokkum, Pieter %A Wijers, Nastasha %A Schaye, Joop %D 2019 %K library %T On the detectability of visible-wavelength line emission from the local circumgalactic and intergalactic medium %U http://arxiv.org/abs/1904.07874 %X 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 ($z$ $łesssim$ 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 $\gtrsim700$ 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.

@misc{lokhorst2019detectability, 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 $\gtrsim700$ 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.}, added-at = {2019-04-18T04:59:41.000+0200}, author = {Lokhorst, Deborah and Abraham, Roberto and van Dokkum, Pieter and Wijers, Nastasha and Schaye, Joop}, biburl = {https://www.bibsonomy.org/bibtex/269babf7381869033f9b5c4e781e2bd21/gpkulkarni}, description = {On the detectability of visible-wavelength line emission from the local circumgalactic and intergalactic medium}, interhash = {f07b61fc84749b86616f80843a1e530a}, intrahash = {69babf7381869033f9b5c4e781e2bd21}, keywords = {library}, note = {cite arxiv:1904.07874Comment: 18 pages, 12 figures. Accepted for publication in ApJ}, timestamp = {2019-04-18T04:59:41.000+0200}, title = {On the detectability of visible-wavelength line emission from the local circumgalactic and intergalactic medium}, url = {http://arxiv.org/abs/1904.07874}, year = 2019 }