Abstract
The use of background quasars provides a powerful tool to probe the cool gas in the circum-galactic medium of foreground galaxies. Here, we present new observations with SINFONI and X-Shooter of absorbing-galaxy candidates at z=0.7-1. We report the detection with both instruments of the H-alpha emission line of one sub-DLA at z_abs=0.94187 with log N(HI)=19.38^+0.10_-0.15 towards SDSS J002133.27+004300.9. We estimate the star formation rate: SFR=3.6+/-2.2 solar masses per year in that system. A detailed kinematic study indicates a dynamical mass M_dyn=10^9.9+/-0.4 solar masses and a halo mass M_halo=10^11.9+/-0.5 solar masses. In addition, we report the OII detection with X-Shooter of another DLA at z_abs=0.7402 with log N(HI)=20.4+/-0.1 toward Q0052+0041 and an estimated SFR of 5.3+/-0.7 solar masses per year. Three other objects are detected in the continuum with X-Shooter but the nature and redshift of two of these objects are unconstrained due to the absence of emission lines, while the third object might be at the redshift of the quasar. We use the objects detected in our whole N(HI)-selected SINFONI survey to compute the metallicity difference between the galaxy and the absorbing gas, delta_HI(X), where a positive (negative) value indicates infall (outflow). We compare this quantity with the quasar line of sight alignment with the galaxy's major (minor) axis, another tracer of infall (outflow). We find that these quantities do not correlate as expected from simple assumptions. Additional observations are necessary to relate these two independent probes of gas flows around galaxies.
Highlights
While the large-scale intergalactic medium (IGM) and small-scale processes within the galaxies are better un- Quasara CoordinatesaV Mag zquasar zabs N (H I) b b [”] [kpc] Inst
In the NIR arm of our X-Shooter observation, we report a faint continuum at the expected position of the absorbinggalaxy candidate
The black crosses refer to z∼1 targets observed in J-band with SINFONI, while the red crosses are objects lying at z∼2 observed in K-band
Summary
Observations of the IGM indicate significant quantities of metals at all redshifts (Pettini 2003; Ryan-Weber et al 2009; Tumlinson et al 2011; Cooksey et al 2013; Werk et al 2013; Shull, Danforth & Tilton 2014) The presence of these metals is interpreted as a signature of strong galactic outflows in various models (Aguirre et al 2001; Oppenheimer & Dave 2006; Pieri, Martel & Grenon 2007). A sample of Mg ii absorbers was used to study winds and infall near galaxies at z∼1 and z∼2 (Bouche et al 2007, 2013; Schroetter et al 2015), up to a redshift close to the peak of cosmic star formation activity. Throughout this paper, we assume a cosmology with H0=71 km/s/Mpc, ΩM =0.27 and ΩΛ=0.73
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