Roman-Cosmic Noon: A Legacy Spectroscopic Survey of Massive Field and Protocluster Galaxies at 2<z<32<z<3

Protoclusters are the densest regions in the distant universe ($z>2$) and are the progenitors of massive galaxy clusters ($M_{halo}>10^{14}{\rm M}_\odot$) in the local universe. They undoubtedly play a key role in early massive galaxy evolution and they may host the earliest sites of galaxy quenching or even induce extreme states of star formation. Studying protoclusters therefore not only gives us a window into distant galaxy formation but also provides an important link in our understanding of how dense structures grow over time and modify the galaxies within them. Current protocluster samples are completely unable to address these points because they are small and selected in a heterogeneous way. We propose the Roman-Cosmic Noon survey, whose centerpiece is an extremely deep (30ksec) and wide area (10 deg$^2$) prism slitless spectroscopy survey to identify the full range of galaxy structures at $2<z<3$. This survey will include 1500 uniformly selected protoclusters, their surrounding cosmic web environments, and at least 15,000 protocluster galaxies with $M_\star>10^{10.5} {\rm M}_\odot$ across the full range of star formation histories as well as many more lower mass star-forming galaxies. The survey will also contain field galaxies to much lower masses than in the High Latitude Wide Area Survey, but over an area dwarfing any current or planned deep spectroscopy probe at $z>2$. With the prism spectroscopy and some modest additional imaging this survey will measure precise stellar mass functions, quenched fractions, galaxy and protocluster morphologies, stellar ages, emission-line based SFRs, and metallicities. It will have extensive legacy value well beyond the key protocluster science goals.Comment: Submitted to the 2023 call for White Papers regarding the Roman Mission Core Community Surveys, 6 pages, 3 figure

Hα star formation main sequence in cluster and field galaxies at z ∼ 1.6

We calculate Hα-based star formation rates and determine the star formation rate–stellar mass relation for members of three Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS) clusters at z ∼ 1.6 and serendipitously identified field galaxies at similar redshifts to the clusters. We find similar star formation rates in cluster and field galaxies throughout our range of stellar masses. The results are comparable to those seen in other clusters at similar redshifts, and consistent with our previous photometric evidence for little quenching activity in clusters. One possible explanation for our results is that galaxies in our z ∼ 1.6 clusters have been accreted too recently to show signs of environmental quenching. It is also possible that the clusters are not yet dynamically mature enough to produce important environmental quenching effects shown to be important at low redshift, such as ram-pressure stripping or harassment

The GOGREEN Survey: A deep stellar mass function of cluster galaxies at 1.0 < z < 1.4 and the complex nature of satellite quenching

We study the stellar mass functions (SMFs) of star-forming and quiescent galaxies in 11 galaxy clusters at 1.0 < z < 1.4 drawn from the Gemini Observations of Galaxies in Rich Early ENvironments (GOGREEN) survey. Based on more than 500 h of Gemini/GMOS spectroscopy and deep multi-band photometry taken with a range of observatories, we probe the SMFs down to a stellar mass limit of 109.7 M⊙ (109.5 M⊙ for star-forming galaxies). At this early epoch, the fraction of quiescent galaxies is already highly elevated in the clusters compared to the field at the same redshift. The quenched fraction excess (QFE) represents the fraction of galaxies that would be star-forming in the field but are quenched due to their environment. The QFE is strongly mass dependent, and increases from ∼30% at M⋆ = 109.7 M⊙ to ∼80% at M⋆ = 1011.0 M⊙. Nonetheless, the shapes of the SMFs of the two individual galaxy types, star-forming and quiescent galaxies, are identical between cluster and field to high statistical precision. Nevertheless, along with the different quiescent fractions, the total galaxy SMF is also environmentally dependent, with a relative deficit of low-mass galaxies in the clusters. These results are in stark contrast with findings in the local Universe, and therefore require a substantially different quenching mode to operate at early times. We discuss these results in light of several popular quenching models.G.R. acknowledges support from the National Science Foundation grants AST-1517815, AST-1716690, and AST-1814159 and NASA HST grant AR-14310.. R.D. gratefully acknowledges support from the Chilean Centro de Excelencia en Astrofísica y Tecnologías Afines (CATA) BASAL grant AFB-170002.P.C. acknowledges the support of the ALMACONICYT grant no 31180051. This work is supported by the National Science Foundation through grant AST-1517863, by HST program number GO-15294, and by grant number 80NSSC17K0019 issued through the NASA Astrophysics Data Analysis Program (ADAP)This work was supported in part by NSF grants AST-1815475 and AST-1518257. Additional support was provided by NASA through grant AR-14289 from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 769130). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 833824). BV acknowledges financial contribution from the grant PRIN MIUR 2017 n.20173ML3WW_001 (PI Cimatti) and from the INAF main-stream funding programme (PI Vulcani). Based on observations obtained at the Gemini Observatory (GS LP-1 and GN LP-4), which is operated by the Association of Universities for Research in Astronom

The GOGREEN Survey: Evidence of an excess of quiescent disks in clusters at 1.0<z<1.41.0<z<1.4

We present results on the measured shapes of 832 galaxies in 11 galaxy clusters at 1.0 < z <1.4 from the GOGREEN survey. We measure the axis ratio ($q$), the ratio of the minor to the major axis, of the cluster galaxies from near-infrared Hubble Space Telescope imaging using S\'ersic profile fitting and compare them with a field sample. We find that the median $q$ of both star-forming and quiescent galaxies in clusters increases with stellar mass, similar to the field. Comparing the axis ratio distributions between clusters and the field in four mass bins, the distributions for star-forming galaxies in clusters are consistent with those in the field. Conversely, the distributions for quiescent galaxies in the two environments are distinct, most remarkably in $10.1\leq\log(M/{\rm M}_{\odot})<10.5$ where clusters show a flatter distribution, with an excess at low $q$. Modelling the distribution with oblate and triaxial components, we find that the cluster and field sample difference is consistent with an excess of flattened oblate quiescent galaxies in clusters. The oblate population contribution drops at high masses, resulting in a narrower $q$ distribution in the massive population than at lower masses. Using a simple accretion model, we show that the observed $q$ distributions and quenched fractions are consistent with a scenario where no morphological transformation occurs for the environmentally quenched population in the two intermediate mass bins. Our results suggest that environmental quenching mechanism(s) likely produce a population that has a different morphological mix than those resulting from the dominant quenching mechanism in the field.Comment: Accepted for publication in ApJ. 25 pages, 15 figure

Gogreen : A critical assessment of environmental trends in cosmological hydrodynamical simulations at z approximate to 1

Peer reviewe

Gemini Observations of Galaxies in Rich Early Environments (GOGREEN) I : survey description

We describe a new Large Program in progress on the Gemini North and South telescopes: Gemini Observations of Galaxies in Rich Early Environments (GOGREEN). This is an imaging and deep spectroscopic survey of 21 galaxy systems at 1 10 in halo mass. The scientific objectives include measuring the role of environment in the evolution of low-mass galaxies, and measuring the dynamics and stellar contents of their host haloes. The targets are selected from the SpARCS, SPT, COSMOS, and SXDS surveys, to be the evolutionary counterparts of today's clusters and groups. The new red-sensitive Hamamatsu detectors on GMOS, coupled with the nod-and-shuffle sky subtraction, allow simultaneous wavelength coverage over lambda similar to 0.6-1.05 mu m, and this enables a homogeneous and statistically complete redshift survey of galaxies of all types. The spectroscopic sample targets galaxies with AB magnitudes z' <24.25 and [3.6] mu m <22.5, and is therefore statistically complete for stellar masses M* greater than or similar to 10(10.3) M-circle dot, for all galaxy types and over the entire redshift range. Deep, multiwavelength imaging has been acquired over larger fields for most systems, spanning u through K, in addition to deep IRAC imaging at 3.6 mu m. The spectroscopy is similar to 50 per cent complete as of semester 17A, and we anticipate a final sample of similar to 500 new cluster members. Combined with existing spectroscopy on the brighter galaxies from GCLASS, SPT, and other sources, GOGREEN will be a large legacy cluster and field galaxy sample at this redshift that spectroscopically covers a wide range in stellar mass, halo mass, and clustercentric radius.Peer reviewe

The stellar mass function of quiescent galaxies in 2 < z < 2.5 protoclusters

We present an analysis of the galaxy stellar mass function (SMF) of 14 known protoclusters between 2.0 10 10.5 M⊙) quiescent galaxies by a factor ≳ 2. However, we find that at lower masses (⁠⁠M* < 10 10.5 M⊙), no additional environmental quenching is required