Search

The Charting Cluster Construction with VUDS and ORELSE (C3VO) survey is an ongoing imaging and spectroscopic campaign aiming to map out the growth of structure up to $z\sim5$ and was born from the combination of the VIMOS Ultra Deep Survey (VUDS) and the Observations of Redshift Evolution in Large-Scale Environments (ORELSE) survey. As we previously accomplished with the ORELSE survey, we apply our technique known as Voronoi tessellation Monte-Carlo (VMC) mapping to search for serendipitous galaxy overdensities at $2 14$. In the C3VO fields, we were able to recover many of the previously known structures in the literature as well as find hundreds of new overdensity candidates, once again demonstrating the powerful capabilities of VMC mapping when applied to wide-field optical and infrared galaxy evolution surveys at ever higher redshifts., Comment: 36 pages, 16 figures, 5 tables, submitted to ApJ

We conduct a study on the relationship between galaxy environments and their active galactic nuclei (AGN) activity at high redshifts ($2.010^{12.8}M_\odot$) overdense ($\sigma_\delta>5.0$) peak, normalized with respect to the size of the peak. These findings indicate that the prevalence of AGN activity is highly dependent on the environment in which a host galaxy resides, even at early times in the formation history of the Universe., Comment: 15 pages, 11 figures, submitted to A&A, comments welcome

We present an analysis of the number density of galaxies as a function of stellar mass (i.e., the stellar mass function, SMF) in the COSMOS field at z~3.3, making a comparison between the SMF in overdense environments and the SMF in the coeval field. In particular, this region contains the Elent\'ari proto-supercluster, a system of 6 extended overdensities spanning ~70 cMpc on a side. A clear difference is seen in the high-mass slope of these SMFs, with overdense regions showing an increase in the ratio of high-mass galaxies to low-mass galaxies relative to the field, indicating a more rapid build-up of stellar mass in overdense environments. This result qualitatively agrees with analyses of clusters at z~1, though the differences between protocluster and field SMFs at z~3.3 are smaller. While this is consistent with overdensities enhancing the evolution of their member galaxies, potentially through increased merger rates, whether this enhancement begins in protocluster environments or even earlier in group environments is still unclear. Though the measured fractions of quiescent galaxies between the field and overdense environments do not vary significantly, implying that this stellar mass enhancement is ongoing and any starbursts triggered by merger activity have not yet quenched, we note that spectroscopic observations are biased towards star-forming populations, particularly for low-mass galaxies. If mergers are indeed responsible, high resolution imaging of Elent\'ari and similar structures at these early epochs should then reveal increased merger rates relative to the field. Larger samples of well-characterized overdensities are necessary to draw broader conclusions in these areas., Comment: 15 pages, 8 figures, plus references and appendices. Submitted to ApJ, posted after responding to referee comments. Further comments welcome

Recent James Webb Space Telescope (JWST) observations have revealed a surprisingly abundant population of faint, dusty active galactic nuclei (AGNs) at z~4-7. Together with the presence of supermassive black holes (SMBHs) at z>6, this raises questions about the formation and growth histories of early black holes. Current theories for the formation of seed black holes from the death of the first stars (i.e. light seeds) and/or the direct collapse of primordial gas clouds (i.e. heavy seeds) still lack observational confirmation. Here, we present LID-568, a low-mass (7.2e6Msun) black hole hosting powerful outflows that is observed in an extreme phase of rapid growth at z~4. This object is similar to other JWST-discovered faint AGN populations, but is bright in X-ray emission and accreting at more than 4000% of the limit at which radiation pressure exceeds the force of gravitational attraction of the black hole (i.e. super-Eddington accretion). Analysis of JWST NIRSpec/IFU data reveals spatially extended Ha emission with velocities of ~ -600 - -500 km/s relative to the central black hole, indicative of robust nuclear-driven outflows. LID-568 represents an elusive low-mass black hole experiencing super-Eddington accretion as invoked by models of early black hole formation. This discovery showcases a previously undiscovered key parameter space and offers crucial insights into rapid black hole growth mechanisms in the early universe., Comment: Submitted

Simulations predict that the galaxy populations inhabiting protoclusters may contribute considerably to the total amount of stellar mass growth of galaxies in the early universe. In this study, we test these predictions observationally, focusing on the Taralay protocluster (formerly PCl J1001+0220) at $z \sim 4.57$ in the COSMOS field. Leveraging data from the Charting Cluster Construction with VUDS and ORELSE (C3VO) survey, we spectroscopically confirmed 44 galaxies within the adopted redshift range of the protocluster ($4.48 < z < 4.64$) and incorporate an additional 18 such galaxies from ancillary spectroscopic surveys. Using a density mapping technique, we estimate the total mass of Taralay to be $\sim 1.7 \times 10^{15}$ M$_\odot$, sufficient to form a massive cluster by the present day. By comparing the star formation rate density (SFRD) within the protocluster (SFRD$_\text{pc}$) to that of the coeval field (SFRD$_\text{field}$), we find that SFRD$_\text{pc}$ surpasses the SFRD$_\text{field}$ by $\Delta$log(SFRD/$M_\odot$ yr$^{-1}$ Mpc$^{-3}$) = $1.08 \pm 0.32$ (or $\sim$ 12$\times$). The observed contribution fraction of protoclusters to the cosmic SFRD adopting Taralay as a proxy for typical protoclusters is $33.5\%^{+8.0\%}_{-4.3\%}$, a value $\sim$2$\sigma$ in excess of the predictions from simulations. Taralay contains three peaks that are $5\sigma$ above the average density at these redshifts. Their SFRD is $\sim$0.5 dex higher than the value derived for the overall protocluster. We show that 68% of all star formation in the protocluster takes place within these peaks, and that the innermost regions of the peaks encase $\sim 50\%$ of the total star formation in the protocluster. This study strongly suggests that protoclusters drive stellar mass growth in the early universe and that this growth may proceed in an inside-out manner., Comment: 26 pages, 14 figures, 10 tables

We present six spectroscopically confirmed massive protostructures, spanning a redshift range of $2.59000$\thinspace cMpc$^3$) of more than $2.5\sigma_{\delta}$ above the field density levels at these redshifts, have a total mass $M_{tot}\ge10^{14.8}M_\odot$ and one or more highly overdense (overdensity$\thinspace>5\sigma_{\delta}$) peaks. One of the most complex protostructures discovered is a massive ($M_{tot}=10^{15.1}M_\odot$) system at $z\sim3.47$ that contains six peaks and 55 spectroscopic members. We also discover protostructures at $z\sim3.30$ and $z\sim3.70$ that appear to at least partially overlap on sky with the protostructure at $z\sim3.47$, suggesting a possible connection. We additionally report on the discovery of three massive protostructures at $z=2.67$, 2.80, and 4.14 and discuss their properties. Finally, we discuss the relationship between star formation rate and environment in the richest of these protostructures, finding an enhancement of star formation activity in the densest regions. The diversity of the protostructures reported here provide an opportunity to study the complex effects of dense environments on galaxy evolution over a large redshift range in the early universe., Comment: 10 pages, 4 figures, 1 table

We attempt to a detect signal of Yarkovsky-related acceleration in the orbits of 134 main belt asteroids (MBAs) we observed with the University of Hawai'i 88 inch telescope, supplemented with observations publicly available from the Minor Planet Center and Gaia Data Release 3. We estimated expected Yarkovsky acceleration values based on parameters derived through thermophysical modeling, but we were not able to find any reliable detections of Yarkovsky in our sample. Through tests with synthetic observations however, we estimated the minimum observational arc length needed to detect the Yarkovsky effect for all of our sample MBAs, which in nearly every case exceeded the current arc length of the existing observations. We find that the Yarkovsky effect could be detectable within a couple of decades of discovery for a 100 m MBA assuming 0.1" astrometric accuracy, which is at the size range detectable by the upcoming Vera Rubin Observatory Legacy Survey of Space and Time., Comment: 28 pages, 6 figures, 6 tables, accepted by PSJ

Motivated by spectroscopic confirmation of three overdense regions in the COSMOS field at $z\sim3.35$, we analyze the uniquely deep multi-wavelength photometry and extensive spectroscopy available in the field to identify any further related structure. We construct a three dimensional density map using the Voronoi tesselation Monte Carlo method and find additional regions of significant overdensity. Here we present and examine a set of six overdense structures at $3.205\sigma$ overdensity separated by up to 70 cMpc, suggestive of a proto-supercluster similar to the Hyperion system at $z\sim2.45$. Upcoming photometric surveys with JWST such as COSMOS-Web, and further spectroscopic follow-up will enable more extensive analysis of the evolutionary effects that such an environment may have on its component galaxies at these early times., Comment: Accepted for publication in MNRAS. 7 pages, 3 figures, 3 tables

Long-period comet C/2018 F4 (PANSTARRS) was observed to show duplicity of its inner region in 2020 September, suggestive of a splitting event. We here present analyses of our observations of the comet taken from the LOOK project and the University of Hawaii 2.2 m telescope after the discovery of the splitting. The two fragments Components A and B, estimated to be $\sim\!60$ m to 4 km in radius, remained highly similar to each other in terms of brightness, colour, and dust morphology throughout our observing campaign from 2020 September to 2021 December. Our fragmentation model yielded that the two components split at a relative speed of $3.00 \pm 0.18$ m s$^{-1}$ in 2020 late April, implying a specific energy change of $\left(5.3 \pm 2.8 \right) \times 10^3$ J kg$^{-1}$, and that Component B was subjected to a stronger nongravitational acceleration than Component A in both the radial and normal directions of the orbit. The obtained splitting time is broadly consistent with the result from the dust morphology analysis, which further suggested that the dominant dust grains were millimeter-sized and ejected at speed $\sim\!2$ m s$^{-1}$. We postulate that the pre-split nucleus of the comet consisted of two lobes resembling the one of 67P, or that the comet used to be a binary system like main-belt comet 288P. Regardless, we highlight the possibility of using observations of split comets as a feasible manner to study the bilobate shape or binarity fraction of cometary nuclei., Comment: Accepted to AJ for publication

We present the radio properties of 66 spectroscopically-confirmed normal star-forming galaxies (SFGs) at $4.4

We present new thermophysical model (TPM) fits of 1,847 asteroids, deriving thermal inertia, diameter, and Bond and visible geometric albedo. We use thermal flux measurements obtained by the Wide-field Infrared Survey Explorer (WISE; Wright et al. 2010; Mainzer et al. 2011) during its fully cryogenic phase, when both the 12$\mu$m (W3) and 22$\mu$m (W4) bands were available. We take shape models and spin information from the Database of Asteroid Models from Inversion Techniques (DAMIT; \v{D}urech et al. 2010) and derive new shape models through lightcurve inversion and combining WISE photometry with existing DAMIT lightcurves. When we limit our sample to the asteroids with the most reliable shape models and thermal flux measurements, we find broadly consistent thermal inertia relations with recent studies. We apply fits to the diameters $D$ (km) and thermal inertia $\Gamma$ (J m$^{-2}$ s$^{-0.5}$ K$^{-1}$) normalized to 1 au with a linear relation of the form $\log[\Gamma]=\alpha+\beta\log[D]$, where we find $\alpha = 2.667 \pm 0.059$ and $\beta = -0.467 \pm 0.044$ for our sample alone and $\alpha = 2.509 \pm 0.017$ and $\beta = -0.352 \pm 0.012$ when combined with other literature estimates. We find little evidence of any correlation between rotation period and thermal inertia, owing to the small number of slow rotators to consider in our sample. While the large uncertainties on the majority of our derived thermal inertia only allow us to identify broad trends between thermal inertia and other physical parameters, we can expect a significant increase in high-quality thermal flux measurements and asteroid shape models with upcoming infrared and wide-field surveys, enabling even more thermophysical modeling of higher precision in the future., Comment: 86 pages, 17 figures, 6 tables, accepted by PSJ with proof corrections. Table 5, now corrected, was erroneously published with a different definition for "dense lightcurve", using 15 data points as a minimum rather than 30, so several asteroids had higher numbers of dense lightcurves than presented elsewhere in the paper

Radio Active Galactic Nuclei (RAGNs) are mainly found in dense structures (i.e., clusters/groups) at redshifts of z$<$2 and are commonly used to detect protoclusters at higher redshift. Here, we attempt to study the host and environmental properties of two relatively faint ($\mathrm L_\mathrm{1.4GHz} \sim10^{25}$ W Hz$^{-1}$) RAGNs in a known protocluster at z=3.3 in the PCl J0227-0421 field, detected using the latest radio observation obtained as part of the Observations of Redshift Evolution in Large-Scale Environments (ORELSE) Survey. Using new spectroscopic observations obtained from Keck/MOSFIRE as part of the Charting Cluster Construction with the VIMOS Ultra-Deep Survey (VUDS) and ORELSE (C3VO) survey and previous spectroscopic data obtained as part of the VIMOS-VLT Deep Survey (VVDS) and VUDS, we revise the three-dimensional overdensity field around this protocluster. The protocluster is embedded in a large scale overdensity protostructure. This protostructure has an estimated total mass of $\sim$2.6$\times10^{15} M_\odot$ and contains several overdensity peaks. Both RAGNs are hosted by very bright and massive galaxies, while their hosts show extreme differences color, indicating that they have different ages and are in different evolutionary stages. Furthermore, we find that they are not in the most locally dense parts of the protostructure, but are fairly close to the centers of their parent overdensity peaks. We propose a scenario where merging might already have happened in both cases, which lowered the local density of their surrounding area and boosted their stellar mass. This work is the first time that two RAGNs at low luminosity have been found and studied within a high redshift protostructure., Comment: 23 pages, 11 figures, 4 tables, accepted by ApJ

Recent hydrodynamic simulations and observations of radio jets have shown that the surrounding environment has a large effect on their resulting morphology. To investigate this we use a sample of 50 Extended Radio Active Galactic Nuclei (ERAGN) detected in the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey. These sources are all successfully cross-identified to galaxies within a redshift range of $0.55 \leq z \leq 1.35$, either through spectroscopic redshifts or accurate photometric redshifts. We find that ERAGN are more compact in high-density environments than those in low-density environments at a significance level of 4.5$\sigma$. Among a series of internal properties under our scrutiny, only the radio power demonstrates a positive correlation with their spatial extent. After removing the possible radio power effect, the difference of size in low- and high-density environments persists. In the global environment analyses, the majority (86\%) of high-density ERAGN reside in the cluster/group environment. In addition, ERAGN in the cluster/group central regions are preferentially compact with a small scatter in size, compared to those in the cluster/group intermediate regions and fields. In conclusion, our data appear to support the interpretation that the dense intracluster gas in the central regions of galaxy clusters plays a major role in confining the spatial extent of radio jets.

We present a study of interstellar comet 2I/2019 Q4 (Borisov) using both preperihelion and postperihelion observations spanning late September 2019 through late January 2020. The intrinsic brightness of the comet was observed to continuously decline throughout the timespan, likely due to the decreasing effective scattering cross-section as a result of volatile sublimation with a slope of $-0.43 \pm 0.02$ km$^{2}$ d$^{-1}$. We witnessed no significant change in the slightly reddish colour of the comet, with mean values of $\left \langle g - r \right \rangle = 0.68 \pm 0.04$, $\left \langle r - i \right \rangle = 0.23 \pm 0.03$, and the normalised reflectivity gradient across the $g$ and $i$ bands $\overline{S'} \left(g,i\right) = \left(10.6 \pm 1.4\right)$ % per $10^3$ \AA, all unremarkable in the context of solar system comets. Using the available astrometric observations, we confidently detect the nongravitational acceleration of the comet following a shallow heliocentric distance dependency of $r_{\rm H}^{-1 \pm 1}$. Accordingly, we estimate that the nucleus is most likely $\lesssim$0.4 km in radius, and that a fraction of $\gtrsim$0.2% of the total nucleus in mass has been eroded due to the sublimation activity since the earliest observation of the comet in 2018 December by the time of perihelion. Our morphology simulation suggests that the dust ejection speed increased from $\sim$4 m s$^{-1}$ in September 2019 to $\sim$7 m s$^{-1}$ around perihelion for the optically dominant dust grains of $\beta \sim 0.01$, and that the observable dust grains are no smaller than micron size., Comment: Accepted for publication in Astronomical Journal

In this study we investigate 179 radio-IR galaxies drawn from a sample of spectroscopically-confirmed galaxies that are detected in radio and mid-infrared (MIR) in the redshift range of $0.55 \leq z \leq 1.30$ in the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey. We constrain the Active Galactic Nuclei (AGN) contribution in the total IR luminosity (f$_{\text{AGN}}$), and estimate the AGN luminosity (L$_{\text{AGN}}$) and the star formation rate (SFR) using the CIGALE Spectral Energy Distribution (SED) fitting routine. Based on the f$_{\text{AGN}}$ and radio luminosity, radio-IR galaxies are split into: galaxies that host either high or low f$_{\text{AGN}}$ AGN (high-/low-f$_{\text{AGN}}$), and star forming galaxies with little to no AGN activity (SFGs). We study the colour, stellar mass, radio luminosity, L$_{\text{AGN}}$ and SFR properties of the three radio-IR sub-samples, comparing to a spec-IR sample drawn from spectroscopically-confirmed galaxies that are also detected in MIR. No significant difference between radio luminosity of these sub-samples was found, which could be due to the combined contribution of radio emission from AGN and star formation. We find a positive relationship between L$_{\text{AGN}}$and specific SFR (sSFR) for both AGN sub-samples, strongly suggesting a co-evolution scenario of AGN and SF in these galaxies. A toy model is designed to demonstrate this co-evolution scenario, where we find that, in almost all cases, a rapid quenching timescale is required, which we argue is a signature of AGN quenching. The environmental preference for intermediate/infall regions of clusters/groups remains across the co-evolution scenario, which suggests that galaxies might be in an orbital motion around the cluster/group during the scenario.

We present a study of the star-formation rate (SFR)-density relation at z ~ 0.9 using data drawn from the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey. We find that SFR does depend on environment, but only for intermediate-stellar mass galaxies (10^10.1 < M* / Msol < 10^10.8) wherein the median SFR at the highest densities is 0.2-0.3 dex less than at lower densities at a significance of 4 sigma. Interestingly, mass does not drive SFR; galaxies that are more/less massive have SFRs that vary at most by ~20% across all environments showing no statistically significant dependence. We further split galaxies into low-redshift (z ~ 0.8) and high-redshift (z ~ 1.05) subsamples and observe nearly identical behavior. We devise a simple toy model to explore possible star-formation histories (SFHs) for galaxies evolving between these redshifts. The key assumption in this model is that star-forming galaxies in a given environment-stellar mass bin can be described as a superposition of two exponential timescales (SFR ~ e^(-t/tau)): a long-tau timescale with tau = 4 Gyr to simulate "normal" star-forming galaxies, and a short-tau timescale with free tau (between 0.3 < tau/Gyr < 2) to simulate galaxies on a quenching trajectory. In general we find that galaxies residing in low/high environmental densities are more heavily weighted to the long-tau/short-tau pathways respectively, which we argue is a signature of environmental quenching. Furthermore, for intermediate-stellar mass galaxies this transition begins at intermediate-density environments suggesting that environmental quenching is relevant in group-like halos and/or cluster infall regions., Comment: 17 pages, 7 figures

Using ~5000 spectroscopically-confirmed galaxies drawn from the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey we investigate the relationship between color and galaxy density for galaxy populations of various stellar masses in the redshift range $0.55 \le z \le 1.4$. The fraction of galaxies with colors consistent with no ongoing star formation ($f_q$) is broadly observed to increase with increasing stellar mass, increasing galaxy density, and decreasing redshift, with clear differences observed in $f_q$ between field and group/cluster galaxies at the highest redshifts studied. We use a semi-empirical model to generate mock group/cluster galaxies unaffected by environmental processes and compare them to observed populations to constrain the environmental quenching efficiency ($\Psi_{convert}$). High-density environments from $0.55 \le z \le 1.4$ appear capable of efficiently quenching galaxies with $\log(M_{\ast}/M_{\odot})>10.45$. Lower stellar mass galaxies also appear efficiently quenched at the lowest redshifts, but this efficiency drops precipitously with increasing redshift. Quenching efficiencies, combined with simulated group/cluster accretion histories and results from a companion ORELSE study, are used to constrain the average time from group/cluster accretion to quiescence and the time between accretion and the inception of quenching. These timescales were constrained to be <$t_{convert}$>=$2.4\pm0.3$ and <$t_{delay}$>=$1.3\pm0.4$ Gyr, respectively, for galaxies with $\log(M_{\ast}/M_{\odot})>10.45$ and <$t_{convert}$>=$3.3\pm0.3$ and <$t_{delay}$>=$2.2\pm0.4$ Gyr for lower stellar mass galaxies. These quenching efficiencies and associated timescales are used to rule out certain environmental mechanisms as being those primarily responsible for transforming the star-formation properties of galaxies over this 4 Gyr window in cosmic time., Comment: 26 pages, 8 Figures, 4 Tables. Updated with the accepted MNRAS version that includes minor changes to the analysis and text