scholarly journals Clustering with JWST: Constraining galaxy host halo masses, satellite quenching efficiencies, and merger rates at z  = 4−10

2020 ◽  
Vol 493 (1) ◽  
pp. 1178-1196 ◽  
Author(s):  
Ryan Endsley ◽  
Peter Behroozi ◽  
Daniel P Stark ◽  
Christina C Williams ◽  
Brant E Robertson ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Mass Relation ◽  
Relative Role ◽  
Galaxy Clustering ◽  
Redshift Galaxy ◽  
Stellar Halo ◽  
Major Merger ◽  
Halo Masses ◽  
Time Observation

ABSTRACT Galaxy clustering measurements can be used to constrain many aspects of galaxy evolution, including galaxy host halo masses, satellite quenching efficiencies, and merger rates. We simulate JWST galaxy clustering measurements at z ∼ 4–10 by utilizing mock galaxy samples produced by an empirical model, the universemachine. We also adopt the survey footprints and typical depths of the planned joint NIRCam and NIRSpec Guaranteed Time Observation program planned for Cycle 1 to generate realistic JWST survey realizations and to model high-redshift galaxy selection completeness. We find that galaxy clustering will be measured with ≳5σ significance at z ∼ 4–10. Halo mass precisions resulting from Cycle 1 angular clustering measurements will be ∼0.2 dex for faint (−18 ≳ $\mathit {M}_{\mathrm{UV}}^{ }$ ≳ −19) galaxies at z ∼ 4–10 as well as ∼0.3 dex for bright ($\mathit {M}_{\mathrm{UV}}^{ }$ ∼ −20) galaxies at z ∼ 4–7. Dedicated spectroscopic follow-up over ∼150 arcmin2 would improve these precisions by ∼0.1 dex by removing chance projections and low-redshift contaminants. Future JWST observations will therefore provide the first constraints on the stellar–halo mass relation in the epoch of reionization and substantially clarify how this relation evolves at z > 4. We also find that ∼1000 individual satellites will be identifiable at z ∼ 4–8 with JWST, enabling strong tests of satellite quenching evolution beyond currently available data (z ≲ 2). Finally, we find that JWST observations can measure the evolution of galaxy major merger pair fractions at z ∼ 4–8 with ∼0.1–0.2 dex uncertainties. Such measurements would help determine the relative role of mergers to the build-up of stellar mass into the epoch of reionization.

scholarly journals The evolution of sizes and specific angular momenta in hierarchical models of galaxy formation and evolution

2019 ◽  
Vol 487 (4) ◽  
pp. 5649-5665 ◽  
Author(s):  
Anna Zoldan ◽  
Gabriella De Lucia ◽  
Lizhi Xie ◽  
Fabio Fontanot ◽  
Michaela Hirschmann
Keyword(s):  
Galaxy Evolution ◽  
Galaxy Formation ◽  
High Redshift ◽  
Retention Factor ◽  
Mass Relation ◽  
Massive Galaxies ◽  
Star Forming ◽  
Stellar Halo ◽  
Compact Galaxies ◽  
Good Agreement

ABSTRACTWe extend our previous work focused at z ∼ 0, studying the redshift evolution of galaxy dynamical properties using the state-of-the-art semi-analytic model GAEA (GAlaxy Evolution and Assembly): we show that the predicted size–mass relation for discy/star-forming and quiescent galaxies is in good agreement with observational estimates, up to z ∼ 2. Bulge-dominated galaxies have sizes that are offset low with respect to observational estimates, mainly due to our implementation of disc instability at high redshift. At large masses, both quiescent and bulge-dominated galaxies have sizes smaller than observed. We interpret this as a consequence of our most massive galaxies having larger gas masses than observed, and therefore being more affected by dissipation. We argue that a proper treatment of quasar-driven winds is needed to alleviate this problem. Our model compact galaxies have number densities in agreement with observational estimates and they form most of their stars in small and low angular momentum high-z haloes. GAEA predicts that a significant fraction of compact galaxies forming at high-z is bound to merge with larger structures at lower redshifts: therefore they are not the progenitors of normal-size passive galaxies at z = 0. Our model also predicts a stellar–halo size relation that is in good agreement with observational estimates. The ratio between stellar size and halo size is proportional to the halo spin and does not depend on stellar mass but for the most massive galaxies, where active galactic nucleus feedback leads to a significant decrease of the retention factor (from about 80 per cent to 20 per cent).

scholarly journals Quasi-equilibrium models of high-redshift disc galaxy evolution

2020 ◽  
Vol 500 (3) ◽  
pp. 3394-3412
Author(s):  
Steven R Furlanetto
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
High Redshift ◽  
Formation Rate ◽  
New Physics ◽  
Small Scale ◽  
Quasi Equilibrium ◽  
Mass Relation ◽  
Disc Galaxy

ABSTRACT In recent years, simple models of galaxy formation have been shown to provide reasonably good matches to available data on high-redshift luminosity functions. However, these prescriptions are primarily phenomenological, with only crude connections to the physics of galaxy evolution. Here, we introduce a set of galaxy models that are based on a simple physical framework but incorporate more sophisticated models of feedback, star formation, and other processes. We apply these models to the high-redshift regime, showing that most of the generic predictions of the simplest models remain valid. In particular, the stellar mass–halo mass relation depends almost entirely on the physics of feedback (and is thus independent of the details of small-scale star formation) and the specific star formation rate is a simple multiple of the cosmological accretion rate. We also show that, in contrast, the galaxy’s gas mass is sensitive to the physics of star formation, although the inclusion of feedback-driven star formation laws significantly changes the naive expectations. While these models are far from detailed enough to describe every aspect of galaxy formation, they inform our understanding of galaxy formation by illustrating several generic aspects of that process, and they provide a physically grounded basis for extrapolating predictions to faint galaxies and high redshifts currently out of reach of observations. If observations show violations from these simple trends, they would indicate new physics occurring inside the earliest generations of galaxies.

scholarly journals Shedding light on high-redshift galaxies with the 21cm signal

2019 ◽  
Vol 15 (S352) ◽  
pp. 69-69
Author(s):  
Anne Hutter
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Neutral Hydrogen ◽  
First Stars ◽  
High Redshift Galaxies ◽  
Redshift Galaxy ◽  
First Galaxies ◽  
Galaxy Population ◽  
The Impact ◽  
Redshift Galaxies

AbstractReionization represents an important epoch in the history in the Universe, when the first stars and galaxies gradually ionize the neutral hydrogen in the intergalactic medium (IGM). Understanding the nature of the ionizing sources, the associated ionization of the IGM, and its impact on subsequent structure formation and galaxy evolution by means of radiative feedback effects, represent key outstanding questions in current astrophysics. High-redshift galaxy observations and simulations have significantly extended our knowledge on the nature of high-redshift galaxies. However, essential properties such as the escape fraction of ionizing photons from galaxies into the IGM and their dependency on galactic properties remain essentially unknown, but determine significantly the distribution and time evolution of the ionized regions during reionization. Analyzing this ionization topology by means of the neutral hydrogen sensitive 21cm signal with radio interferometers such as SKA offers a complementary and unique opportunity to determine the nature of these first galaxies. I will show results from a self-consistent semi-numerical model of galaxy evolution and reionization, and discuss the potential of inferring galactic properties with the 21cm signal as well as the impact of reionization on the high-redshift galaxy population and its evolution.

scholarly journals Studying the physical properties of tidal features – I. Extracting morphological substructure in CANDELS observations and VELA simulations

2019 ◽  
Vol 486 (2) ◽  
pp. 2643-2659 ◽  
Author(s):  
Kameswara Bharadwaj Mantha ◽  
Daniel H McIntosh ◽  
Cody P Ciaschi ◽  
Rubyet Evan ◽  
Henry C Ferguson ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
Software Tool ◽  
Space Telescope ◽  
Visual Appearance ◽  
James Webb Space Telescope ◽  
Profile Fitting ◽  
Major Merger ◽  
Merger Rate

Abstract The role of major mergers in galaxy evolution remains a key open question. Existing empirical merger identification methods use non-parametric and subjective visual classifications that can pose systematic challenges to constraining merger histories. As a first step towards overcoming these challenges, we develop and share publicly a new python-based software tool that identifies and extracts the flux-wise and area-wise significant contiguous regions from the model-subtracted residual images produced by popular parametric light-profile fitting tools (e.g. galfit). Using Hubble Space Telescope (HST) H-band single-Sérsic residual images of 17 CANDELS galaxies, we demonstrate the tools ability to measure the surface brightness and improve the qualitative identification of a variety of common residual features (disc structures, spiral substructures, plausible tidal features, and strong gravitational arcs). We test our method on synthetic HST observations of a z ∼ 1.5 major merger from the VELA hydrodynamic simulations. We extract H-band residual features corresponding to the birth, growth, and fading of tidal features during different stages and viewing orientations at CANDELS depths and resolution. We find that the extracted features at shallow depths have noisy visual appearance and are susceptible to viewing angle effects. For a VELA z ∼ 3 major merger, we find that James Webb Space Telescope NIRCam observations can probe high-redshift tidal features with considerable advantage over existing HST capabilities. Further quantitative analysis of plausible tidal features extracted with our new software hold promise for the robust identification of hallmark merger signatures and corresponding improvements to merger rate constraints.

scholarly journals The MUSEHubbleUltra Deep Field Survey

2017 ◽  
Vol 608 ◽  
pp. A9 ◽  
Author(s):  
E. Ventou ◽  
T. Contini ◽  
N. Bouché ◽  
B. Epinat ◽  
J. Brinchmann ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Cosmic Time ◽  
Spectral Energy ◽  
Close Pair ◽  
Major Merger ◽  
Stellar Masses ◽  
Good Agreement ◽  
Close Pairs

We provide, for the first time, robust observational constraints on the galaxy major merger fraction up toz≈ 6 using spectroscopic close pair counts. Deep Multi Unit Spectroscopic Explorer (MUSE) observations in theHubbleUltra Deep Field (HUDF) andHubbleDeep Field South (HDF-S) are used to identify 113 secure close pairs of galaxies among a parent sample of 1801 galaxies spread over a large redshift range (0.2 <z< 6) and stellar masses (107−1011M⊙), thus probing about 12 Gyr of galaxy evolution. Stellar masses are estimated from spectral energy distribution (SED) fitting over the extensive UV-to-NIR HST photometry available in these deepHubblefields, addingSpitzerIRAC bands to better constrain masses for high-redshift (z⩾ 3) galaxies. These stellar masses are used to isolate a sample of 54 major close pairs with a galaxy mass ratio limit of 1:6. Among this sample, 23 pairs are identified at high redshift (z⩾ 3) through their Lyαemission. The sample of major close pairs is divided into five redshift intervals in order to probe the evolution of the merger fraction with cosmic time. Our estimates are in very good agreement with previous close pair counts with a constant increase of the merger fraction up toz≈ 3 where it reaches a maximum of 20%. At higher redshift, we show that the fraction slowly decreases down to about 10% atz≈ 6. The sample is further divided into two ranges of stellar masses using either a constant separation limit of 109.5M⊙or the median value of stellar mass computed in each redshift bin. Overall, the major close pair fraction for low-mass and massive galaxies follows the same trend. These new, homogeneous, and robust estimates of the major merger fraction sincez≈ 6 are in good agreement with recent predictions of cosmological numerical simulations.

scholarly journals Hawaii Two-0: high-redshift galaxy clustering and bias

2020 ◽  
Vol 493 (2) ◽  
pp. 2318-2328
Author(s):  
Róbert Beck ◽  
Conor McPartland ◽  
Andrew Repp ◽  
David Sanders ◽  
István Szapudi
Keyword(s):  
High Redshift ◽  
Self Organizing Map ◽  
Redshift Distribution ◽  
Galaxy Clustering ◽  
Photometric Redshift ◽  
Redshift Galaxy ◽  
The Galaxy ◽  
Strategic Program ◽  
Galaxy Bias ◽  
The University

ABSTRACT We perform an analysis of two-point galaxy clustering and galaxy bias using Subaru Hyper-Suprime Cam (HSC) data taken jointly by the Subaru Strategic Program and the University of Hawaii in the Cosmic Evolution Survey (COSMOS) field over an area of 1.8 sq deg. The depth of the data is similar to the ongoing Hawaii Two-0 (H20) optical galaxy survey, thus the results are indicative of future constraints from tenfold area. We measure the angular autopower spectra of the galaxy overdensity in three redshift bins, defined by dropouts from the g, r, and i bands, and compare them to the theoretical expectation from concordance cosmology with linear galaxy bias. We determine the redshift distribution of each bin using a standard template-based photometric redshift method, coupled with a self-organizing map to quantify colour space coverage. We also investigate sources of systematic errors to inform the methodology and requirements for H20. The linear galaxy bias fit results are $b_{\mathrm{gal,g}} = 3.90 \pm 0.33 (\mathrm{stat}) \substack{ +0.64 \\ -0.24 } (\mathrm{sys})$ at redshift z ≃ 3.7, $b_{\mathrm{gal,r}} = 8.44 \pm 0.63 (\mathrm{stat}) \substack{ +1.42 \\ -0.72 } (\mathrm{sys})$ at z ≃ 4.7, and $b_{\mathrm{gal,i}} = 11.94 \pm 2.24 (\mathrm{stat}) \substack{ +1.82 \\ -1.27 } (\mathrm{sys})$ at z ≃ 5.9.

scholarly journals Lyman Break Analogs: Constraints on the Formation of Extreme Starbursts at Low and High Redshift

2010 ◽  
Vol 6 (S277) ◽  
pp. 146-149
Author(s):  
Thiago S. Gonçalves ◽  
Roderik Overzier ◽  
Antara Basu-Zych ◽  
D. Christopher Martin
Keyword(s):  
High Redshift ◽  
Clear Correlation ◽  
Star Forming ◽  
Integral Field Spectroscopy ◽  
Lyman Break Galaxies ◽  
Redshift Galaxy ◽  
Major Merger ◽  
Kinematic Studies ◽  
Galaxy Population ◽  
Kinematic Properties

AbstractLyman Break Analogs (LBAs), characterized by high far-UV luminosities and surface brightnesses as detected by GALEX, are intensely star-forming galaxies in the low-redshift universe (z ~ 0.2), with star formation rates reaching up to 50 times that of the Milky Way. These objects present metallicities, morphologies and other physical properties similar to higher redshift Lyman Break Galaxies (LBGs), motivating the detailed study of LBAs as local laboratories of this high-redshift galaxy population. We present results from our recent integral-field spectroscopy survey of LBAs with Keck/OSIRIS, which shows that these galaxies have the same nebular gas kinematic properties as high-redshift LBGs. We argue that such kinematic studies are not an appropriate diagnostic to rule out merger events as the trigger for the observed starburst. Comparison between the kinematic analysis and morphological indices from HST imaging illustrates the difficulties of properly identifying (minor or major) merger events, with no clear correlation between the results using either of the two methods. Artificial redshifting of our data indicates that this problem becomes even worse at high redshift due to surface brightness dimming and resolution loss. Whether mergers could generate the observed kinematic properties is strongly dependent on gas fractions in these galaxies. We present preliminary results of a CARMA survey for LBAs and discuss the implications of the inferred molecular gas masses for formation models.

scholarly journals The impact of scatter in the galaxy UV luminosity to halo mass relation on Ly α visibility during the epoch of reionization

2020 ◽  
Vol 495 (4) ◽  
pp. 3602-3613 ◽  
Author(s):  
Lily R Whitler ◽  
Charlotte A Mason ◽  
Keven Ren ◽  
Mark Dijkstra ◽  
Andrei Mesinger ◽  
...  
Keyword(s):  
Dark Matter ◽  
High Redshift ◽  
Neutral Hydrogen ◽  
Dark Matter Halo ◽  
Mass Relation ◽  
Lyman Alpha ◽  
Redshift Galaxy ◽  
The Galaxy ◽  
Improved Model ◽  
The Impact

ABSTRACT The reionization of hydrogen is closely linked to the first structures in the Universe, so understanding the timeline of reionization promises to shed light on the nature of these early objects. In particular, transmission of Lyman alpha (Ly α) from galaxies through the intergalactic medium (IGM) is sensitive to neutral hydrogen in the IGM, so can be used to probe the reionization timeline. In this work, we implement an improved model of the galaxy UV luminosity to dark matter halo mass relation to infer the volume-averaged fraction of neutral hydrogen in the IGM from Ly α observations. Many models assume that UV-bright galaxies are hosted by massive dark matter haloes in overdense regions of the IGM, so reside in relatively large ionized regions. However, observations and N-body simulations indicate that scatter in the UV luminosity–halo mass relation is expected. Here, we model the scatter (though we assume the IGM topology is unaffected) and assess the impact on Ly α visibility during reionization. We show that UV luminosity–halo mass scatter reduces Ly α visibility compared to models without scatter, and that this is most significant for UV-bright galaxies. We then use our model with scatter to infer the neutral fraction, $\overline{x}_{\mathrm{ H}\,{\small I}}$, at z ∼ 7 using a sample of Lyman-break galaxies in legacy fields. We infer $\overline{x}_{\mathrm{ H}\,{\small I}} = 0.55_{-0.13}^{+0.11}$ with scatter, compared to $\overline{x}_{\mathrm{ H}\,{\small I}} = 0.59_{-0.14}^{+0.12}$ without scatter, a very slight decrease and consistent within the uncertainties. Finally, we place our results in the context of other constraints on the reionization timeline and discuss implications for future high-redshift galaxy studies.

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