@article{momose_catch_2021,
	title = {Catch {Me} if {You} {Can}: {Biased} {Distribution} of {Ly}\${\textbackslash}alpha\$-emitting {Galaxies} according to the {Viewing} {Direction}},
	volume = {2104},
	shorttitle = {Catch {Me} if {You} {Can}},
	url = {http://adsabs.harvard.edu/abs/2021arXiv210410580M},
	abstract = {We report that Ly\${\textbackslash}alpha\$-emitting galaxies (LAEs) may not faithfully 
trace the cosmic web of neutral hydrogen (HI), but their distribution is
likely biased depending on the viewing direction. We calculate the
cross-correlation (CCF) between galaxies and Ly\${\textbackslash}alpha\$ forest
transmission fluctuations on the near and far sides of the galaxies
separately, for three galaxy samples at \$z{\textbackslash}sim2\$: LAEs, [OIII] emitters
(O3Es), and continuum-selected galaxies. We find that only LAEs have
anisotropic CCFs, with the near side one showing lower signals up to
\$r=3-4{\textasciitilde}h{\textasciicircum}\{-1\}\$ comoving Mpc. This means that the average HI density on
the near side of LAEs is lower than that on the far-side by a factor of
\$2.1\$ under the Fluctuating Gunn-Peterson Approximation. Mock LAEs
created by assigning Ly\${\textbackslash}alpha\$ equivalent width
(\$EW\_{\textbackslash}text\{Ly\${\textbackslash}alpha\$\}{\textasciicircum}{\textbackslash}text\{obs\}\$) values to O3Es with an empirical
relation also show similar, anisotropic CCFs if we use only objects with
higher \$EW\_{\textbackslash}text\{Ly\${\textbackslash}alpha\$\}{\textasciicircum}{\textbackslash}text\{obs\}\$ than a certain threshold. These
results indicate that galaxies on the far side of a dense region are
more difficult to be detected ("hidden") in Ly\${\textbackslash}alpha\$ because
Ly\${\textbackslash}alpha\$ emission toward us is absorbed by dense neutral hydrogen. If
the same region is viewed from a different direction, a different set of
LAEs will be selected as if galaxies are playing hide-and-seek using HI
gas. Care is needed when using LAEs to search for overdensities.},
	urldate = {2021-05-04},
	journal = {arXiv e-prints},
	author = {Momose, Rieko and Shimasaku, Kazuhiro and Nagamine, Kentaro and Shimizu, Ikkoh and Kashikawa, Nobunari and Ando, Makoto and Kusakabe, Haruka},
	month = apr,
	year = {2021},
	keywords = {Astrophysics - Astrophysics of Galaxies},
	pages = {arXiv:2104.10580},
}

{"_id":"QQGhjH2tormPyC4Ph","bibbaseid":"momose-shimasaku-nagamine-shimizu-kashikawa-ando-kusakabe-catchmeifyoucanbiaseddistributionoflytextbackslashalphaemittinggalaxiesaccordingtotheviewingdirection-2021","author_short":["Momose, R.","Shimasaku, K.","Nagamine, K.","Shimizu, I.","Kashikawa, N.","Ando, M.","Kusakabe, H."],"bibdata":{"bibtype":"article","type":"article","title":"Catch Me if You Can: Biased Distribution of Ly\\${\\textbackslash}alpha\\$-emitting Galaxies according to the Viewing Direction","volume":"2104","shorttitle":"Catch Me if You Can","url":"http://adsabs.harvard.edu/abs/2021arXiv210410580M","abstract":"We report that Ly\\${\\textbackslash}alpha\\$-emitting galaxies (LAEs) may not faithfully trace the cosmic web of neutral hydrogen (HI), but their distribution is likely biased depending on the viewing direction. We calculate the cross-correlation (CCF) between galaxies and Ly\\${\\textbackslash}alpha\\$ forest transmission fluctuations on the near and far sides of the galaxies separately, for three galaxy samples at \\$z{\\textbackslash}sim2\\$: LAEs, [OIII] emitters (O3Es), and continuum-selected galaxies. We find that only LAEs have anisotropic CCFs, with the near side one showing lower signals up to \\$r=3-4{\\textasciitilde}h{\\textasciicircum}\\{-1\\}\\$ comoving Mpc. This means that the average HI density on the near side of LAEs is lower than that on the far-side by a factor of \\$2.1\\$ under the Fluctuating Gunn-Peterson Approximation. Mock LAEs created by assigning Ly\\${\\textbackslash}alpha\\$ equivalent width (\\$EW_{\\textbackslash}text\\{Ly\\$\\textbackslashalpha\\$\\}{\\textasciicircum}{\\textbackslash}text\\{obs\\}\\$) values to O3Es with an empirical relation also show similar, anisotropic CCFs if we use only objects with higher \\$EW_{\\textbackslash}text\\{Ly\\$\\textbackslashalpha\\$\\}{\\textasciicircum}{\\textbackslash}text\\{obs\\}\\$ than a certain threshold. These results indicate that galaxies on the far side of a dense region are more difficult to be detected (\"hidden\") in Ly\\${\\textbackslash}alpha\\$ because Ly\\${\\textbackslash}alpha\\$ emission toward us is absorbed by dense neutral hydrogen. If the same region is viewed from a different direction, a different set of LAEs will be selected as if galaxies are playing hide-and-seek using HI gas. Care is needed when using LAEs to search for overdensities.","urldate":"2021-05-04","journal":"arXiv e-prints","author":[{"propositions":[],"lastnames":["Momose"],"firstnames":["Rieko"],"suffixes":[]},{"propositions":[],"lastnames":["Shimasaku"],"firstnames":["Kazuhiro"],"suffixes":[]},{"propositions":[],"lastnames":["Nagamine"],"firstnames":["Kentaro"],"suffixes":[]},{"propositions":[],"lastnames":["Shimizu"],"firstnames":["Ikkoh"],"suffixes":[]},{"propositions":[],"lastnames":["Kashikawa"],"firstnames":["Nobunari"],"suffixes":[]},{"propositions":[],"lastnames":["Ando"],"firstnames":["Makoto"],"suffixes":[]},{"propositions":[],"lastnames":["Kusakabe"],"firstnames":["Haruka"],"suffixes":[]}],"month":"April","year":"2021","keywords":"Astrophysics - Astrophysics of Galaxies","pages":"arXiv:2104.10580","bibtex":"@article{momose_catch_2021,\n\ttitle = {Catch {Me} if {You} {Can}: {Biased} {Distribution} of {Ly}\\${\\textbackslash}alpha\\$-emitting {Galaxies} according to the {Viewing} {Direction}},\n\tvolume = {2104},\n\tshorttitle = {Catch {Me} if {You} {Can}},\n\turl = {http://adsabs.harvard.edu/abs/2021arXiv210410580M},\n\tabstract = {We report that Ly\\${\\textbackslash}alpha\\$-emitting galaxies (LAEs) may not faithfully \ntrace the cosmic web of neutral hydrogen (HI), but their distribution is\nlikely biased depending on the viewing direction. We calculate the\ncross-correlation (CCF) between galaxies and Ly\\${\\textbackslash}alpha\\$ forest\ntransmission fluctuations on the near and far sides of the galaxies\nseparately, for three galaxy samples at \\$z{\\textbackslash}sim2\\$: LAEs, [OIII] emitters\n(O3Es), and continuum-selected galaxies. We find that only LAEs have\nanisotropic CCFs, with the near side one showing lower signals up to\n\\$r=3-4{\\textasciitilde}h{\\textasciicircum}\\{-1\\}\\$ comoving Mpc. This means that the average HI density on\nthe near side of LAEs is lower than that on the far-side by a factor of\n\\$2.1\\$ under the Fluctuating Gunn-Peterson Approximation. Mock LAEs\ncreated by assigning Ly\\${\\textbackslash}alpha\\$ equivalent width\n(\\$EW\\_{\\textbackslash}text\\{Ly\\${\\textbackslash}alpha\\$\\}{\\textasciicircum}{\\textbackslash}text\\{obs\\}\\$) values to O3Es with an empirical\nrelation also show similar, anisotropic CCFs if we use only objects with\nhigher \\$EW\\_{\\textbackslash}text\\{Ly\\${\\textbackslash}alpha\\$\\}{\\textasciicircum}{\\textbackslash}text\\{obs\\}\\$ than a certain threshold. These\nresults indicate that galaxies on the far side of a dense region are\nmore difficult to be detected (\"hidden\") in Ly\\${\\textbackslash}alpha\\$ because\nLy\\${\\textbackslash}alpha\\$ emission toward us is absorbed by dense neutral hydrogen. If\nthe same region is viewed from a different direction, a different set of\nLAEs will be selected as if galaxies are playing hide-and-seek using HI\ngas. Care is needed when using LAEs to search for overdensities.},\n\turldate = {2021-05-04},\n\tjournal = {arXiv e-prints},\n\tauthor = {Momose, Rieko and Shimasaku, Kazuhiro and Nagamine, Kentaro and Shimizu, Ikkoh and Kashikawa, Nobunari and Ando, Makoto and Kusakabe, Haruka},\n\tmonth = apr,\n\tyear = {2021},\n\tkeywords = {Astrophysics - Astrophysics of Galaxies},\n\tpages = {arXiv:2104.10580},\n}\n\n","author_short":["Momose, R.","Shimasaku, K.","Nagamine, K.","Shimizu, I.","Kashikawa, N.","Ando, M.","Kusakabe, H."],"key":"momose_catch_2021","id":"momose_catch_2021","bibbaseid":"momose-shimasaku-nagamine-shimizu-kashikawa-ando-kusakabe-catchmeifyoucanbiaseddistributionoflytextbackslashalphaemittinggalaxiesaccordingtotheviewingdirection-2021","role":"author","urls":{"Paper":"http://adsabs.harvard.edu/abs/2021arXiv210410580M"},"keyword":["Astrophysics - Astrophysics of Galaxies"],"metadata":{"authorlinks":{}}},"bibtype":"article","biburl":"https://bibbase.org/zotero/polyphant","dataSources":["7gvjSdWrEu7z5vjjj"],"keywords":["astrophysics - astrophysics of galaxies"],"search_terms":["catch","biased","distribution","textbackslash","alpha","emitting","galaxies","according","viewing","direction","momose","shimasaku","nagamine","shimizu","kashikawa","ando","kusakabe"],"title":"Catch Me if You Can: Biased Distribution of Ly\\${\\textbackslash}alpha\\$-emitting Galaxies according to the Viewing Direction","year":2021}