LBT/ARGOS adaptive optics observations of z ∼ 2 lensed galaxies

Abstract

Aims. Gravitationally lensed systems allow a detailed view of galaxies at high redshift. High spatial-and spectral-resolution measurements of arc-like structures can offer unique constraints on the physical and dynamical properties of high-z systems. Methods. We present near-infrared spectra centred on the gravitational arcs of six known z ∼ 2 lensed star-forming galaxies of stellar masses of 10 9−11 M and star formation rate (SFR) in the range between 10 and 400 M /yr. Ground layer adaptive optics (AO)assisted observations are obtained at the Large Binocular Telescope (LBT) with the LUCI spectrographs during the commissioning of the ARGOS facility. We used MOS masks with curved slits to follow the extended arched structures and study the diagnostic emission lines. LBT observations are used to demonstrate the spectroscopic capabilities of ARGOS. Results. Combining spatially resolved kinematic properties across the arc-like morphologies, emission line diagnostics and archival information, we distinguish between merging and rotationally supported systems, and reveal the possible presence of ejected gas. For galaxies that have evidence for outflows, we derive outflow energetics and mass-loading factors compatible with those observed for stellar winds in local and high-z galaxies. We also use flux ratio diagnostics to derive gas-phase metallicities. The low signal-to-noise ratio in the faint Hβ and nitrogen lines allows us to derive an upper limit of ≈ 0.15 dex for the spatial variations in metallicity along the slit for the lensed galaxy J1038. Conclusions. Analysed near-infrared spectra presented here represent the first scientific demonstration of performing AO-assisted multi-object spectroscopy with narrow curved-shape slits. The increased angular and spectral resolution, combined with the binocular operation mode with the 8.4-m-wide eyes of LBT, will allow the characterisation of kinematic and chemical properties of a large sample of galaxies at high-z in the near future.

MUSE view of Arp220: Kpc-scale multi-phase outflow and evidence for positive feedback

“…Chevalier 1974;Schneider et al 2020). Similarly, the mass-loading factor µ = Ṁout /SFR = 0.2 is similar to those measured in other local ULIRGs (Arribas et al 2014;Chisholm et al 2017;Cresci et al 2017) and high-z star-forming galaxies (Genzel et al 2014;Newman et al 2012;Perna et al 2018) with SB-driven outflows. However, the momentum rate generally observed in SB-driven outflows is 10 times smaller than the one derived for Arp220 (see e.g.…”

Molecular gas content in obscured AGN at z > 1

“…All lensed galaxy luminosities have been therefore corrected for lens magnification factors, which may be affected by large uncertainties (see e.g. Feruglio et al 2014;Perna et al 2018). We are confident, however, that the L IR we report in this work are generally a good approximation of the dustemission related to SF.…”

Physics of ULIRGs with MUSE and ALMA: The PUMA project

“…From an observational point of view, ordered disk-like kinematics are generally observed in merger systems, both at low z (Bellocchi et al 2013;Medling et al 2014;Ueda et al 2014;Barrera-Ballesteros et al 2015;Perna et al 2019) and at high z (up to z 4; e.g. Hammer et al 2009;Alaghband-Zadeh et al 2012;Harrison et al 2012;Perna et al 2018;Leung et al 2019;Tadaki et al 2020;Cochrane et al 2021).…”