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TY - JOUR
T1 - The Strong Gravitationally Lensed Herschel Galaxy HLock01
T2 - Optical Spectroscopy Reveals a Close Galaxy Merger with Evidence of Inflowing Gas
AU - Marques-Chaves, Rui
AU - Pérez-Fournon, Ismael
AU - Gavazzi, Raphael
AU - Martínez-Navajas, Paloma I.
AU - Riechers, Dominik
AU - Rigopoulou, Dimitra
AU - Cabrera-Lavers, Antonio
AU - Clements, David L.
AU - Cooray, Asantha
AU - Farrah, Duncan
AU - Ivison, Rob J.
AU - Jiménez-Ángel, Camilo E.
AU - Nayyeri, Hooshang
AU - Oliver, Seb
AU - Omont, Alain
AU - Scott, Douglas
AU - Shu, Yiping
AU - Wardlow, Julie
N1 - © 2018. The American Astronomical Society. All rights reserved.
PY - 2018/2/21
Y1 - 2018/2/21
N2 - The submillimeter galaxy (SMG) HERMES J105751.1+573027 (hereafter HLock01) at z = 2.9574 ± 0.0001 is one of the brightest gravitationally lensed sources discovered in the Herschel Multi-tiered Extragalactic Survey. Apart from the high flux densities in the far-infrared, it is also extremely bright in the rest-frame ultraviolet (UV), with a total apparent magnitude m UV ≃ 19.7 mag. We report here deep spectroscopic observations with the Gran Telescopio Canarias of the optically bright lensed images of HLock01. Our results suggest that HLock01 is a merger system composed of the Herschel-selected SMG and an optically bright Lyman break-like galaxy (LBG), separated by only 3.3 kpc in projection. While the SMG appears very massive (M * ≃ 5 × 1011 M ⊙), with a highly extinguished stellar component (A V ≃ 4.3 ), the LBG is a young, lower-mass (M * ≃ 1 × 1010 M ⊙), but still luminous (10× {L}UV}* ) satellite galaxy. Detailed analysis of the high signal-to-noise ratio (S/N) rest-frame UV spectrum of the LBG shows complex kinematics of the gas, exhibiting both blueshifted and redshifted absorption components. While the blueshifted component is associated with strong galactic outflows from the massive stars in the LBG, as is common in most star-forming galaxies, the redshifted component may be associated with gas inflow seen along a favorable sightline to the LBG. We also find evidence of an extended gas reservoir around HLock01 at an impact parameter of 110 kpc, through the detection of C II λλ1334 absorption in the red wing of a bright Lyα emitter at z ≃ 3.327. The data presented here highlight the power of gravitational lensing in high S/N studies to probe deeply into the physics of high-z star-forming galaxies.
AB - The submillimeter galaxy (SMG) HERMES J105751.1+573027 (hereafter HLock01) at z = 2.9574 ± 0.0001 is one of the brightest gravitationally lensed sources discovered in the Herschel Multi-tiered Extragalactic Survey. Apart from the high flux densities in the far-infrared, it is also extremely bright in the rest-frame ultraviolet (UV), with a total apparent magnitude m UV ≃ 19.7 mag. We report here deep spectroscopic observations with the Gran Telescopio Canarias of the optically bright lensed images of HLock01. Our results suggest that HLock01 is a merger system composed of the Herschel-selected SMG and an optically bright Lyman break-like galaxy (LBG), separated by only 3.3 kpc in projection. While the SMG appears very massive (M * ≃ 5 × 1011 M ⊙), with a highly extinguished stellar component (A V ≃ 4.3 ), the LBG is a young, lower-mass (M * ≃ 1 × 1010 M ⊙), but still luminous (10× {L}UV}* ) satellite galaxy. Detailed analysis of the high signal-to-noise ratio (S/N) rest-frame UV spectrum of the LBG shows complex kinematics of the gas, exhibiting both blueshifted and redshifted absorption components. While the blueshifted component is associated with strong galactic outflows from the massive stars in the LBG, as is common in most star-forming galaxies, the redshifted component may be associated with gas inflow seen along a favorable sightline to the LBG. We also find evidence of an extended gas reservoir around HLock01 at an impact parameter of 110 kpc, through the detection of C II λλ1334 absorption in the red wing of a bright Lyα emitter at z ≃ 3.327. The data presented here highlight the power of gravitational lensing in high S/N studies to probe deeply into the physics of high-z star-forming galaxies.
KW - cosmology: observations
KW - galaxies: evolution
KW - galaxies: individual: HLock01
KW - galaxies: starburst
KW - gravitational lensing: strong
U2 - 10.3847/1538-4357/aaabb7
DO - 10.3847/1538-4357/aaabb7
M3 - Journal article
VL - 854
JO - The Astrophysical Journal
JF - The Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 151
ER -