Behrens, Christoph

[["dc.bibliographiccitation.firstpage","A31"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.volume","614"],["dc.contributor.author","Behrens, Christoph"],["dc.contributor.author","Byrohl, Chris"],["dc.contributor.author","Saito, Shun"],["dc.contributor.author","Niemeyer, Jens C."],["dc.date.accessioned","2020-07-01T08:28:01Z"],["dc.date.available","2020-07-01T08:28:01Z"],["dc.date.issued","2017"],["dc.description.abstract","Lyman-$\\alpha$ emitters (LAEs) are a promising probe of the large-scale structure at high redshift, \\gtrsim 2$. In particular, the Hobby-Eberly Telescope Dark Energy Experiment aims at observing LAEs at 1.9 $<z<$ 3.5 to measure the Baryon Acoustic Oscillation (BAO) scale and the Redshift-Space Distortion (RSD). However, Zheng et al. (2011) pointed out that the complicated radiative transfer (RT) of the resonant Lyman-$\\alpha$ emission line generates an anisotropic selection bias in the LAE clustering on large scales, \\gtrsim 10$ Mpc. This effect could potentially induce a systematic error in the BAO and RSD measurements. Also, Croft et al. (2016) claims an observational evidence of the effect in the Lyman-$\\alpha$ intensity map, albeit statistically insignificant. We aim at quantifying the impact of the Lyman-$\\alpha$ RT on the large-scale galaxy clustering in detail. For this purpose, we study the correlations between the large-scale environment and the ratio of an apparent Lyman-$\\alpha$ luminosity to an intrinsic one, which we call the 'observed fraction', at <z<6$. We apply our Lyman-$\\alpha$ RT code by post-processing the full Illustris simulations. We simply assume that the intrinsic luminosity of the Lyman-$\\alpha$ emission is proportional to the star formation rate of galaxies in Illustris, yielding a sufficiently large sample of LAEs to measure the anisotropic selection bias. We find little correlations between large-scale environment and the observed fraction induced by the RT, and hence a smaller anisotropic selection bias than what was claimed by Zheng et al. (2011). We argue that the anisotropy was overestimated in the previous work due to the insufficient spatial resolution: it is important to keep the resolution such that it resolves the high density region down to the scale of the interstellar medium, $\\sim1$ physical kpc. (abridged)"],["dc.identifier.arxiv","1710.06171v2"],["dc.identifier.doi","10.1051/0004-6361/201731783"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/66816"],["dc.language.iso","en"],["dc.relation.eissn","1432-0746"],["dc.relation.issn","0004-6361"],["dc.title","The impact of Lyman-$α$ radiative transfer on large-scale clustering in the Illustris simulation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5129"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Monthly Notices of the Royal Astronomical Society"],["dc.bibliographiccitation.lastpage","5152"],["dc.bibliographiccitation.volume","506"],["dc.contributor.author","Byrohl, Chris"],["dc.contributor.author","Nelson, Dylan"],["dc.contributor.author","Behrens, Christoph"],["dc.contributor.author","Kostyuk, Ivan"],["dc.contributor.author","Glatzle, Martin"],["dc.contributor.author","Pillepich, Annalisa"],["dc.contributor.author","Hernquist, Lars"],["dc.contributor.author","Marinacci, Federico"],["dc.contributor.author","Vogelsberger, Mark"],["dc.date.accessioned","2021-12-01T09:23:50Z"],["dc.date.available","2021-12-01T09:23:50Z"],["dc.date.issued","2021"],["dc.description.abstract","ABSTRACT Extended Lyman alpha emission is now commonly detected around high-redshift galaxies through stacking and even on individual basis. Despite recent observational advances, the physical origin of these Lyman alpha haloes (LAHs), as well as their relationships to galaxies, quasars, circumgalactic gas, and other environmental factors remains unclear. We present results from our new Lyman alpha full radiative transfer code voroiltis which runs directly on the unstructured Voronoi tessellation of cosmological hydrodynamical simulations. We make use of the TNG50 simulation and simulate LAHs from redshift z = 2 to z = 5, focusing on star-forming galaxies with .0 \\lt \\log _{10}{(M_\\star /\\rm {M}_\\odot)} \\lt 10.5$. While TNG50 does not directly follow ionizing radiation, it includes an on-the-fly treatment for active galactic nuclei (AGNs) and ultraviolet background radiation with self-shielding, which are important processes impacting the cooling and ionization of the gas. Based on this model, we present the predictions for the stacked radial surface brightness profiles of Ly α as a function of galaxy mass and redshift. Comparison with data from the MUSE UDF at z > 3 reveals a promising level of agreement. We measure the correlations of LAH size and central brightness with galaxy properties, finding that at the masses of .5 \\le \\log _{10} \\left(M_\\star /\\rm {M}_\\odot \\right) \\le 9.5$, physical LAH sizes roughly double from z = 2 to z = 5. Finally, we decompose the profiles into contributions from diffuse emission and scattered photons from star-forming regions. In our simulations, we find rescattered photons from star-forming regions to be the major source in observed LAHs. Unexpectedly, we find that the flattening of LAH profiles at large radii becomes dominated by photons originating from other nearby haloes rather than diffuse emission itself."],["dc.description.abstract","ABSTRACT Extended Lyman alpha emission is now commonly detected around high-redshift galaxies through stacking and even on individual basis. Despite recent observational advances, the physical origin of these Lyman alpha haloes (LAHs), as well as their relationships to galaxies, quasars, circumgalactic gas, and other environmental factors remains unclear. We present results from our new Lyman alpha full radiative transfer code voroiltis which runs directly on the unstructured Voronoi tessellation of cosmological hydrodynamical simulations. We make use of the TNG50 simulation and simulate LAHs from redshift z = 2 to z = 5, focusing on star-forming galaxies with .0 \\lt \\log _{10}{(M_\\star /\\rm {M}_\\odot)} \\lt 10.5$. While TNG50 does not directly follow ionizing radiation, it includes an on-the-fly treatment for active galactic nuclei (AGNs) and ultraviolet background radiation with self-shielding, which are important processes impacting the cooling and ionization of the gas. Based on this model, we present the predictions for the stacked radial surface brightness profiles of Ly α as a function of galaxy mass and redshift. Comparison with data from the MUSE UDF at z > 3 reveals a promising level of agreement. We measure the correlations of LAH size and central brightness with galaxy properties, finding that at the masses of .5 \\le \\log _{10} \\left(M_\\star /\\rm {M}_\\odot \\right) \\le 9.5$, physical LAH sizes roughly double from z = 2 to z = 5. Finally, we decompose the profiles into contributions from diffuse emission and scattered photons from star-forming regions. In our simulations, we find rescattered photons from star-forming regions to be the major source in observed LAHs. Unexpectedly, we find that the flattening of LAH profiles at large radii becomes dominated by photons originating from other nearby haloes rather than diffuse emission itself."],["dc.identifier.doi","10.1093/mnras/stab1958"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/94771"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-478"],["dc.relation.eissn","1365-2966"],["dc.relation.issn","0035-8711"],["dc.rights.uri","http://creativecommons.org/licenses/by/4.0/"],["dc.title","The physical origins and dominant emission mechanisms of Lyman alpha haloes: results from the TNG50 simulation in comparison to MUSE observations"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]