Galaxy Evolution with SINS/KMOS3D/PHIBSS/NOEMA3D: Witnessing the Growth of Galaxies at z ~ 1–3 through Spatially and Spectrally Resolved Studies
Kinematics are a powerful tool to understand galaxies’ structures and mass composition, as they directly trace a galaxy’s entire mass. This is one of the only ways to probe components that do not emit light, such as the dark matter halo. To decompose a galaxy’s total dynamics into the contributions from the bulge, disk, and halo, it is necessary to have deep observations so the kinematics can be traced to large galactic radii.
However, distant galaxies at the epoch of peak cosmic star formation (“cosmic noon”, z ~ 1–3) are faint, so obtaining such deep data requires large amounts of observing time even on the largest, most sensitive telescopes currently in operation. Initial studies focusing on a handful of individual galaxies (Genzel et al. 2017, Übler et al. 2018) and on stacked galaxy profiles (Lang et al. 2017) provided useful first constraints, but analyses of larger samples of individual galaxy kinematics are necessary to examine widespread trends.
We have compiled a sample of 100 star-forming galaxies at high redshift (z ~ 1–2) with deep, spatially resolved observations from multiple sources, including the KMOS3D, SINS/zC-SINF, and NOEMA3D surveys as well as additional observations with LBT/LUCI. Using these deep data, we are able to perform such mass modeling to detangle the galaxy and dark matter halo profiles (Genzel et al. 2020, Price et al. 2021).
One of the key findings is that galaxies at cosmic noon (z ~ 1–2) are baryon-dominated on galaxy scales, with higher-mass (or higher-mass surface density) galaxies having lower dark matter fractions. Some of these galaxies have such low fDM(Re) that the profiles of their dark matter halos are likely to be cored, in contrast to predictions for more “peaked” halo profiles (i.e., the NFW profile).
Compared to today’s galaxies (z = 0), the RC100 star-forming disk galaxies at z ~ 1 have similar fDM(Re) – Mbaryon values to the star-forming, disky galaxies, while the RC100 galaxies at z ~ 2 are more like today’s quiescent, elliptical galaxies. These z ~ 2 RC100 galaxies probably represent the progenitor population of today’s elliptical galaxies, with the transformation to quiescence possibly happening not long after the observed epoch, given the overlap with quiescent galaxies seen at z = 1.7 (grey region).
With the ongoing NOEMA3D survey, work will continue to expand this kinematic modeling to more galaxies. Furthermore, using existing data and upcoming observations with VLT/ERIS, we will begin to explore signatures of mass transport and outflows, to better understand bulge growth and other physical processes regulating galaxy growth.
Spatially and spectrally resolved information of the rest-frame optical line and continuum emission is proving very powerful in exploring the physical processes that drive the baryonic mass assembly and star formation of distant galaxies. We have carried out our major surveys of near-IR imaging spectroscopy with SINFONI (SINS/zC-SINF) and KMOS (KMOS3D), and will use ERIS at the Very Large Telescope. Together with Hubble Space Telescope imaging and multiline spectroscopic observations with LUCI at the Large Binocular Telescope, we are investigating in detail the resolved gas kinematics, stellar populations and structure, galactic outflows, excitation, and metallicities of young galaxies from two to eight billion years after the Big Bang. Our PHIBSS/PHIBSS2 and NOEMA3D surveys with the IRAM NOEMA millimeter interferometer provide the essential complementary view of the cold molecular gas content, distribution, and kinematics. These surveys are revealing the importance of internal galaxy dynamics in growing early disks and bulges, and the nature and energetics of feedback – pinning down for the first time details of physical processes driving and regulating early galaxy evolution in the emerging "equilibrium growth model."
SINS/zC-SINF took advantage of the unique opportunities afforded by SINFONI at ESO's Very Large Telescope on Cerro Paranal, Chile, a near-infrared integral field unit (IFU) spectrometer combined with an adaptive optics (AO) system that delivers sharp images simultaneously with high-resolution spectral information. KMOS3D, our multiyear survey with the KMOS instrument as part of Guaranteed Time Observations with MPE/OPINAS and USM, has taken the next major step toward a comprehensive and unbiased view of the resolved properties of galaxies at the heyday of massive galaxy formation. It capitalized on the worldwide unique combination of integral field spectroscopy and multiplexing of KMOS, featuring 24 integral field units patrolling a wide field of 7 arcminutes in diameter. KMOS has opened up an entirely new dimension in detailed spatially and spectrally resolved studies of distant galaxies. Our comprehensive and highly successful KMOS3D survey has collected very sensitive and detailed data of 740 individual targeted objects at 0.6 < z < 2.7 (and 45 serendipitous sources), spanning a wide range in galaxy parameter space and probing into regimes unexplored so far with near-IR IFU studies, such as massive galaxies in the process of quenching their star formation activity. The multiplexing capabilities of the LUCI near-IR multislit spectrograph and imager at the Large Binocular Telescope on Mount Graham, near Tucson, Arizona, make surveys of multiple emission lines of large samples up to 20 times more efficient than single-object long-slit instruments. Coupled with the ground-layer AO system ARGOS, which is currently being commissioned, our high-redshift galaxy research will strongly benefit from several factors: the increased sensitivity, the spatially resolved spectroscopy, and the higher spectral resolution that can be uniformly achieved over a wide field up to 4 arcminutes across with the unprecedented combination of multiplexed spectroscopy and AO-assisted angular resolution with LUCI + ARGOS.
The reduced SINFONI+AO data from the SINS/zC-SINF AO survey are available here.
The dedicated KMOS3D survey web pages and public release of the reduced data cubes are accessible here.
The dedicated PHIBSS 1 & 2 survey web pages and public release are accessible here.
We participate in:
- IMPRS: the International Max Planck Research School on Astrophysics
We were also part of:
- DFG Priority Program SPP1177: "Witnesses of Cosmic History"