The Strong Gravitationally Lensed Herschel Galaxy HLock01: Optical Spectroscopy Reveals a Close Galaxy Merger with Evidence of Inflowing Gas

Abstract

Citation for published item:w rquesEgh vesD ui nd ¡ erezEpournonD ssm el nd q v zziD ph el nd w rt¡ %nezEx v j sD lom sF nd ie hersD hominik nd igopoulouD himitr nd g rer Ev versD entonio nd glementsD h vid vF nd goor yD es nth nd p rr hD hun n nd svisonD o tF nd tim¡ enezE ¡ engelD g milo iF nd x yyeriD roosh ng nd yliverD e nd ymontD el in nd ottD hougl s nd huD iping nd rdlowD tulie @PHIVA 9 he strong gr vit tion lly lensed rers hel q l xy rvo kHI X opti l spe tros opy reve ls lose g l xy merger with eviden e of in)owing g sF9D estrophysi l journ lFD VSR @PAF pF ISIF Further information on publisher's website: Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThe 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×10 11 M e ), with a highly extinguished stellar component (A V ;4.3 ), the LBG is a young, lower-mass (M * ;1×10 10 M e ), but still luminous ( L 10 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.

Discovery of a giant and luminous Lyα+C IV+He II nebula at z = 3.326 with extreme emission line ratios

“…In Marques-Chaves et al (2018) we reported the serendipitous detection of a bright asymmetric line at 5264 Å close to the strong gravitational lensed system HLock01 (z 2.96), consistent with Lyα emission at z ∼ 3.3. The Lyα line was detected in different spatial positions 15 SW from HLock01 (see Figure 1) in two long-slit spectroscopic observations with the Gran Telescopio Canarias (GTC).…”

“…HLock01-LAB shows extended emission over ∼ 100 kpc in the Lyα, C iv, and He ii lines, and presents one of the highest values of Lyα/C iv and Lyα/He ii measured to date. It is located close in projection (∼ 15 ), but physically unrelated to the strong gravitationally lensed Herschel galaxy HLock01 at z 2.96 already discussed in several works Riechers et al 2011;Gavazzi et al 2011;Scott et al 2011;Bussmann et al 2013;Calanog et al 2014;Marques-Chaves et al 2018;Rigopoulou et al 2018).…”

Rest-frame UV properties of luminous strong gravitationally lensed Lyα emitters from the BELLS GALLERY Survey

“…In panel c) of Figure 10 we compare the velocity offset of the ISM absorption lines relative to the systemic redshift and the absolute magnitudes of our LAEs. We also show these quantities measured in other lensed LBGs with damped Lyα absorption (Pettini et al 2000;Dessauges-Zavadsky et al 2010;Quider et al 2010;Marques-Chaves et al 2018) or weak emission (EW 0 < 20Å: Quider et al 2009;Patrício et al 2016). These LBGs also present similar range of UV absolute magnitudes as our LAEs, from −21 to −23.4 (AB).…”

“…where f osc and λ are the ion oscillator strength (Morton 1991) and the transition wavelength (Å). However, ISM lines in LBGs and LAEs present typically saturated profiles when observed with high spectral resolution (e.g., Pettini et al 2002;Dessauges-Zavadsky et al 2010;Jones et al 2012Jones et al , 2013Marques-Chaves et al 2018). To test if some of these lines are saturated or not, we consider the linear part of the curve of growth and use the ratios of EW 0 of different transitions of a given ion.…”

Starburst to Quiescent from HST/ALMA: Stars and Dust Unveil Minor Mergers in Submillimeter Galaxies at z ∼ 4.5

“…In Section 5, we discuss the stellar mass estimates for the different components of each source. Being able to distinguish the components in the lower-resolution data sets, especially in the case of the IRAC bands that trace the rest-frame optical, we obtain stellar masses that are large enough to support the merger scenario, as opposed to patches of a single disk or other form of highly extincted single structure (Marques-Chaves et al 2018).…”