Deep MUSE observations in the HDFS

Abstract

Aims. Whereas the evolution of gas kinematics of massive galaxies is now relatively well established up to redshift z ∼ 3, little is known about the kinematics of lower mass (M ≤ 10 10 M ) galaxies. We use MUSE, a powerful wide-field, optical integral-field spectrograph (IFS) recently mounted on the VLT, to characterize this galaxy population at intermediate redshift.Methods. We made use of the deepest MUSE observations performed so far on the Hubble Deep Field South (HDFS). This data cube, resulting from 27 h of integration time, covers a one arcmin 2 field of view at an unprecedented depth (with a 1σ emission-line surface brightness limit of 1×10 −19 erg s −1 cm −2 arcsec −2 ) and a final spatial resolution of ≈0.7 . We identified a sample of 28 resolved emission-line galaxies, extending over an area that is at least twice the seeing disk, spread over a redshift interval of 0.2 < z < 1.4. More than half of the galaxies are at z ∼ 0.3−0.7, which is a redshift range poorly studied so far with IFS kinematics. We used the public HST images and multiband photometry over the HDFS to constrain the stellar mass and star formation rate (SFR) of the galaxies and to perform a morphological analysis using Galfit, providing estimates of the disk inclination, disk scale length, and position angle of the major axis. We derived the resolved ionized gas properties of these galaxies from the MUSE data and model the disk (both in 2D and in 3D with GalPaK 3D ) to retrieve their intrinsic gas kinematics, including the maximum rotation velocity and velocity dispersion. Results. We build a sample of resolved emission-line galaxies of much lower stellar mass and SFR (by ∼1−2 orders of magnitude) than previous IFS surveys. The gas kinematics of most of the spatially resolved MUSE-HDFS galaxies is consistent with disk-like rotation, but about 20% have velocity dispersions that are larger than the rotation velocities and 30% are part of a close pair and/or show clear signs of recent gravitational interactions. These fractions are similar to what has been found in previous IFS surveys of more massive galaxies, indicating that the dynamical state of the ionized gas and the level of gravitational interactions of star-forming galaxies is not a strong function of their stellar mass. In the high-mass regime, the MUSE-HDFS galaxies follow the Tully-Fisher relation defined from previous IFS surveys in a similar redshift range. This scaling relation also extends to lower masses/velocities but with a higher dispersion. We find that 90% of the MUSE-HDFS galaxies with stellar masses below 10 9.5 M have settled gas disks. The MUSE-HDFS galaxies follow the scaling relations defined in the local Universe between the specific angular momentum and stellar mass. However, we find that intermediate-redshift, star-forming galaxies fill a continuum transition from the spiral to elliptical local scaling relations, according to the dynamical state (i.e., rotation-or dispersion-dominated) of the gas. This indicates that some galaxies may lose their angu...

The MUSEHubbleUltra Deep Field Survey

“…(SED) of galaxies based on the HST photometry, as described in Contini et al (2016) for the HDF-S galaxies. For UDF-Mosaic and udf-10, we used the extended UV-to-NIR ACS and WFC3 photometry of Rafelski et al (2015).…”

X-ray-emitting active galactic nuclei fromz= 0.6 to 1.3 in the intermediate- and high-density environments of the ORELSE survey

“…To investigate a connection between AGN triggering and galaxy interactions, we can locate close kinematic pairs (CKPs), which we define as two galaxies within 70 h −1 kpc on the sky and within 350 km s −1 , typical values for identifying close pairs (See, e.g., Nazaryan et al 2014;Robotham et al 2014;Barrera-Ballesteros et al 2015;Wisnioski et al 2015;Contini et al 2016), using our spectroscopic sample. While galaxies that have recently undergone a merger may not have a close kinematic pair, as the two galaxies may have coalesced, or they may still be too close together to resolve, galaxies that have recently had a more minor interaction should be more likely to lie in close proximity, as should galaxies that will soon undergo interactions.…”

Using photo-ionisation models to derive carbon and oxygen gas-phase abundances in the rest UV

“…These and other followup spectroscopy of galaxies in deep fields (e.g. Erb et al 2010;Karman et al 2015;Contini et al 2016), in particular gravitationally lensed systems (e.g. Christensen et al 2012;James et al 2014;Stark et al 2014;Vanzella et al 2016a), are pushing now UV studies towards the low-luminosity (mass) regime out to redshift z ∼ 3.5 (e.g.…”