TY - JOUR
T1 - MUSE searches for galaxies near very metal-poor gas clouds at z ~ 3
T2 - New constraints for cold accretion models
AU - Fumagalli, Michele
AU - Cantalupo, Sebastiano
AU - Dekel, Avishai
AU - Morris, Simon L.
AU - O'Meara, John M.
AU - Prochaska, J. Xavier
AU - Theuns, Tom
N1 - Publisher Copyright:
© 2016 The Authors.
PY - 2016/10/21
Y1 - 2016/10/21
N2 - We report on the search for galaxies in the proximity of two very metal-poor gas clouds at z ~ 3 towards the quasar Q0956+122. With a 5-hour Multi-Unit Spectroscopic Explorer (MUSE) integration in a ~500 × 500 kpc2 region centred at the quasar position, we achieve a ≥ 80 per cent complete spectroscopic survey of continuum-detected galaxies with mR ≤ 25 mag and Lyα emitters with luminosity LLyα ≥ 3 × 1041 erg s-1. We do not identify galaxies at the redshift of a z ~ 3.2 Lyman limit system (LLS) with log Z/Z⊙ = -3.35 ± 0.05, placing this gas cloud in the intergalactic medium or circumgalactic medium of a galaxy below our sensitivity limits. Conversely, we detect five Lyα emitters at the redshift of a pristine z ~ 3.1 LLS with log Z/Z⊙≤-3.8, while~0.4 sources were expected given the z~3Lyα luminosity function. Both this high detection rate and the fact that at least three emitters appear aligned in projection with the LLS suggest that this pristine cloud is tracing a gas filament that is feeding one or multiple galaxies. Our observations uncover two different environments for metal-poor LLSs, implying a complex link between these absorbers and galaxy haloes, which ongoing MUSE surveys will soon explore in detail. Moreover, in agreement with recent MUSE observations, we detected a ~90 kpc Lyα nebula at the quasar redshift and three Lyα emitters reminiscent of a 'dark galaxy' population.
AB - We report on the search for galaxies in the proximity of two very metal-poor gas clouds at z ~ 3 towards the quasar Q0956+122. With a 5-hour Multi-Unit Spectroscopic Explorer (MUSE) integration in a ~500 × 500 kpc2 region centred at the quasar position, we achieve a ≥ 80 per cent complete spectroscopic survey of continuum-detected galaxies with mR ≤ 25 mag and Lyα emitters with luminosity LLyα ≥ 3 × 1041 erg s-1. We do not identify galaxies at the redshift of a z ~ 3.2 Lyman limit system (LLS) with log Z/Z⊙ = -3.35 ± 0.05, placing this gas cloud in the intergalactic medium or circumgalactic medium of a galaxy below our sensitivity limits. Conversely, we detect five Lyα emitters at the redshift of a pristine z ~ 3.1 LLS with log Z/Z⊙≤-3.8, while~0.4 sources were expected given the z~3Lyα luminosity function. Both this high detection rate and the fact that at least three emitters appear aligned in projection with the LLS suggest that this pristine cloud is tracing a gas filament that is feeding one or multiple galaxies. Our observations uncover two different environments for metal-poor LLSs, implying a complex link between these absorbers and galaxy haloes, which ongoing MUSE surveys will soon explore in detail. Moreover, in agreement with recent MUSE observations, we detected a ~90 kpc Lyα nebula at the quasar redshift and three Lyα emitters reminiscent of a 'dark galaxy' population.
KW - Galaxies: formation
KW - Galaxies: haloes
KW - Galaxies: high-redshift
KW - Intergalactic medium
KW - Quasars: absorption lines
KW - Quasars: individual: Q0956+122
UR - http://www.scopus.com/inward/record.url?scp=84988874539&partnerID=8YFLogxK
U2 - 10.1093/mnras/stw1782
DO - 10.1093/mnras/stw1782
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AN - SCOPUS:84988874539
SN - 0035-8711
VL - 462
SP - 1978
EP - 1988
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -