The Charting Cluster Construction with VUDS and ORELSE (C3VO) survey is an ongoing campaign designed to provide a nearly complete mapping of the five most significant overdensities detected in VIMOS Ultra–Deep Survey.
The C3VO survey utilizes spectra from observations with both DEIMOS and MOSFIRE on the Keck I/II telescopes and VUDS, and employs the Voronoi Monte-Carlo algorithm for local environment measurement, originally developed within the framework of the ORELSE survey. The keck component of the C3VO survey is designed to target star-forming galaxies of all types to i_AB < 25.3 (or ∼ L*FUV at z ∼ 4.5 and < L*FUV at z ∼ 2.5) and Lyman-α emitting galaxies to fainter magnitudes.
The Massive Ancient Galaxies at z>3 NEar-infrared (MAGAZ3NE) Survey is a multi-semester survey using the MOSFIRE instrument on the Keck telescopes in Hawaii. The project has spectroscopically confirmed the largest sample to date of ultramassive galaxies (stellar masses greater than 100 billion suns) from when the Universe was less than 2 billion years old.
Selection of candidate galaxies was done via analysis of deep multi-wavelength photometric catalogs in the VIDEO-XMM, VIDEO-CDFS, and COSMOS-UltraVISTA fields.
Spectral features including [OII] and [OIII] emission lines, Balmer series absorption, and the D4000 break were critical to putting caps on the ongoing star formation and AGN activity, as well as constraining the average age of stars in a galaxy.
Detailed modeling of the star-formation histories for the MAGAZ3NE sample indicates that these galaxies formed the majority of their stars in bursts forming hundreds to thousands of solar masses per year for several hundred million years.
Roughly half of the sample subsequently had their star formation abruptly truncated, putting constraints on the processes responsible for quenching at these early epochs. These galaxies may have run out of pristine gas with which to form new stars, or activity from a supermassive black hole may have snuffed out further star formation. Either way, the early epoch at which such an event must have occurred challenges current models of early galaxy star formation and quenching.
The most extreme of our sample received significant press coverage on sites such as Scientific American, USA Today, CBC, Fox News, and included an interview for the BBC Newsroom.
Models shown in red. Note the clear Balmer absorption features and lack of emission lines.
The Multi-Object Spectroscopic Emission Line (MOSEL) Survey used the MOSFIRE instrument on the Keck telescope to follow-up a sample of galaxies with strong rest-frame optical emission features at 2.5<z<4 first published in Forrest, et al., 2017.
Spectroscopic confirmation of nearly 50 of these objects revealed low-mass galaxies with large gas fractions and [OIII]5007 equivalent widths. This indicates that the high star formation rates of these object could continue for some time, potentially doubling their stellar masses in several tens of Myr (Tran, et al., 2020).
Kinematic analysis reveals that the more massive of these objects have lower velocity dispersions than similar mass galaxies at lower redshifts, implying that ex situ stellar mass fractions increase with cosmic time (Gupta, et al., 2020).
The FourStar Galaxy Evolution Survey (ZFOURGE) was an international collaboration, with members in Australia, the U.S., and Europe.
With 5 near-infrared medium bandpasses and a deep K-band detection image, ZFOURGE provided precise photometric redshifts for galaxies out to z~4. This enabled a wealth of new scientific discoveries in the field of galaxy evolution.
A list of publications, as well as catalogs, images, and an entertaining data explorer are available on the survey website. The survey is described in detail in Straatman, et al., 2016.
Archival photometric bandpasses in the ZFOURGE fields are shown in gray, while the ZFOURGE medium bands are shown in orange.
