WFC3 GRISM CONFIRMATION OF THE DISTANT CLUSTER Cl J1449+0856 AT ⟨z⟩ = 2.00: QUIESCENT AND STAR-FORMING GALAXY POPULATIONS

AbstractWe revisit the bimodality of the galaxy population seen in the local universe. We address this issue in terms of physical properties of galaxies, such as mean stellar ages and stellar masses, derived from the application of a spectral synthesis method to galaxy spectra from the SDSS. We show that the mean light-weighted stellar age of galaxies presents the best description of the bimodality seen in the galaxy population. The stellar mass has an additional role since most of the star-forming galaxies present in the local universe are low-mass galaxies. Our results give support to the existence of a ‘downsizing’ in galaxy formation, where nowadays massive galaxies tend to have stellar populations older than those found in less massive objects.

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In pursuit of giants

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038405 ◽

2020 ◽

Vol 644 ◽

pp. A144

Author(s):

D. Donevski ◽

A. Lapi ◽

K. Małek ◽

D. Liu ◽

C. Gómez-Guijarro ◽

...

Keyword(s):

Star Formation ◽

Galaxy Evolution ◽

Galaxy Formation ◽

Main Sequence ◽

Stellar Mass ◽

Starburst Galaxies ◽

Analytical Models ◽

Physical Parameters ◽

Star Forming ◽

Galaxy Populations

The dust-to-stellar mass ratio (Mdust/M⋆) is a crucial, albeit poorly constrained, parameter for improving our understanding of the complex physical processes involved in the production of dust, metals, and stars in galaxy evolution. In this work, we explore trends of Mdust/M⋆ with different physical parameters and using observations of 300 massive dusty star-forming galaxies detected with ALMA up to z ≈ 5. Additionally, we interpret our findings with different models of dusty galaxy formation. We find that Mdust/M⋆ evolves with redshift, stellar mass, specific star formation rates, and integrated dust size, but that evolution is different for main-sequence galaxies than it is for starburst galaxies. In both galaxy populations, Mdust/M⋆ increases until z ∼ 2, followed by a roughly flat trend towards higher redshifts, suggesting efficient dust growth in the distant universe. We confirm that the inverse relation between Mdust/M⋆ and M⋆ holds up to z ≈ 5 and can be interpreted as an evolutionary transition from early to late starburst phases. We demonstrate that the Mdust/M⋆ in starbursts reflects the increase in molecular gas fraction with redshift and attains the highest values for sources with the most compact dusty star formation. State-of-the-art cosmological simulations that include self-consistent dust growth have the capacity to broadly reproduce the evolution of Mdust/M⋆ in main-sequence galaxies, but underestimating it in starbursts. The latter is found to be linked to lower gas-phase metallicities and longer dust-growth timescales relative to observations. The results of phenomenological models based on the main-sequence and starburst dichotomy as well as analytical models that include recipes for rapid metal enrichment are consistent with our observations. Therefore, our results strongly suggest that high Mdust/M⋆ is due to rapid dust grain growth in the metal-enriched interstellar medium. This work highlights the multi-fold benefits of using Mdust/M⋆ as a diagnostic tool for: (1) disentangling main-sequence and starburst galaxies up to z ∼ 5; (2) probing the evolutionary phase of massive objects; and (3) refining the treatment of the dust life cycle in simulations.

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Jansky VLA S-band view of Hα emitters (HAEs) associated with a protocluster 4C23.56 at z = 2.5

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314009892 ◽

2014 ◽

Vol 10 (S309) ◽

pp. 287-288

Author(s):

Minju Lee ◽

Kenta Suzuki ◽

Kotaro Kohno ◽

Yoichi Tamura ◽

Daisuke Iono ◽

...

Keyword(s):

Galaxy Formation ◽

Narrow Band ◽

Narrow Band Imaging ◽

Large Array ◽

Dense Region ◽

Very Large Array ◽

Star Forming ◽

Dust Extinction ◽

The Galaxy ◽

Galaxy Populations

AbstractWe present recent results on Karl Jansky Very Large Array (JVLA) deep S-band (2-4 GHz) observation towards a protocluster 4C23.56 at redshift z ∼ 2.5. The protocluster 4C23.56 is known to have a significant over density (∼ 5 times) of star-burst galaxies selected to be Hα line-bright by a Subaru narrow band imaging. Now we have found 25 HAEs associated with the protocluster. These starburst HAEs are likely to become massive ellipticals at z = 0 in a cluster. Various other galaxy populations also reside in this field and the fact makes the field very unique as a tool to understand galaxy formation in a over dense region. Subsequent deep 1100-μm continuum surveys by the ASTE 10-m dish have discovered that several submillimeter bright galaxies (SMGs) coincide with HAEs, suggesting HAEs undergoing dusty starbursts. As star formation rates (SFRs) of HAEs might have been underestimated, we use radio being resistant to dust extinction. We investigate the correlation between SFR1.4 GHz and SFRHα for radio index α = 0.8 to see if the correlation holds for the sources and to check the number of dusty star forming galaxies. Our final results will allow us to evaluate quantitatively how the galaxy formation channel may be different under the condition of over-densities.

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Into the Ly α jungle: exploring the circumgalactic medium of galaxies at z ∼ 4−5 with MUSE

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa546 ◽

2020 ◽

Vol 493 (4) ◽

pp. 5336-5356

Author(s):

Richard M Bielby ◽

Michele Fumagalli ◽

Matteo Fossati ◽

Marc Rafelski ◽

Benjamin Oppenheimer ◽

...

Keyword(s):

Absorption Line ◽

Surface Brightness ◽

High Redshift ◽

Radial Profile ◽

Clear Correlation ◽

Star Forming ◽

Wide Range ◽

The Galaxy ◽

Galaxy Environment ◽

Galaxy Populations

ABSTRACT We present a study of the galaxy environment of nine strong H i + C iv absorption line systems (16.2 < log(N(HI)) < 21.2) spanning a wide range in metallicity at z ∼ 4−5, using MUSE integral field and X-Shooter spectroscopic data collected in a z ≈ 5.26 quasar field. We identify galaxies within a 250 kpc and ±1000 km s−1 window for six out of the nine absorption systems, with two of the absorption line systems showing multiple associated galaxies within the MUSE field of view. The space density of Ly α emitting galaxies (LAEs) around the H i and C iv systems is ≈10−20 times the average sky density of LAEs given the flux limit of our survey, showing a clear correlation between the absorption and galaxy populations. Further, we find that the strongest C iv systems in our sample are those that are most closely aligned with galaxies in velocity space, i.e. within velocities of ±500 km s−1. The two most metal-poor systems lie in the most dense galaxy environments, implying we are potentially tracing gas that is infalling for the first time into star-forming groups at high redshift. Finally, we detect an extended Ly α nebula around the z ≈ 5.26 quasar, which extends up to ≈50 kpc at the surface brightness limit of 3.8 × 10−18 erg s−1 cm−2 arcsec−2. After scaling for surface brightness dimming, we find that this nebula is centrally brighter, having a steeper radial profile than the average for nebulae studied at z ∼ 3 and is consistent with the mild redshift evolution seen from z ≈ 2.

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Molecular gas in distant brightest cluster galaxies

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936148 ◽

2020 ◽

Vol 635 ◽

pp. A32 ◽

Cited By ~ 2

Author(s):

G. Castignani ◽

F. Combes ◽

P. Salomé ◽

J. Freundlich

Keyword(s):

Star Formation ◽

Stellar Mass ◽

Star Formation History ◽

Gas Content ◽

Molecular Gas ◽

Distant Cluster ◽

Cluster Galaxies ◽

Star Forming ◽

Distant Star ◽

Brightest Cluster Galaxies

The mechanisms governing the stellar mass assembly and star formation history of brightest cluster galaxies (BCGs) are still being debated. By means of new and archival molecular gas observations we investigate the role of dense megaparsec-scale environments in regulating the fueling of star formation in distant BCGs, through cosmic time. We observed in CO with the IRAM 30 m telescope two star-forming BCGs belonging to SpARCS clusters, namely, 3C 244.1 (z = 0.4) and SDSS J161112.65+550823.5 (z = 0.9), and compared their molecular gas and star formation properties with those of a compilation of ∼100 distant cluster galaxies from the literature, including nine additional distant BCGs at z ∼ 0.4 − 3.5. We set robust upper limits of MH2 < 1.0 × 1010 M⊙ and < 2.8 × 1010 M⊙ to their molecular gas content, respectively, and to the ratio of molecular gas to stellar mass M(H2)/M⋆ ≲ 0.2 and depletion time τdep ≲ 40 Myr of the two targeted BCGs. They are thus among the distant cluster galaxies with the lowest gas fractions and shortest depletion times. The majority (64%±15% and 73%±18%) of the 11 BCGs with observations in CO have lower M(H2)/M⋆ values and τdep, respectively, than those estimated for main sequence galaxies. Statistical analysis also tentatively suggests that the values of M(H2)/M⋆ and τdep for the 11 BCGs deviates, with a significance of ∼2σ, from those of the comparison sample of cluster galaxies. A morphological analysis for a subsample of seven BCGs with archival HST observations reveals that 71%±17% of the BCGs are compact or show star-forming components or substructures. Our results suggest a scenario where distant star-forming BCGs assemble a significant fraction ∼16% of their stellar mass on the relatively short timescale ∼τdep, while environmental mechanisms might prevent the replenishment of gas feeding the star formation. We speculate that compact components also favor the rapid exhaustion of molecular gas and ultimately help to quench the BCGs. Distant star-forming BCGs are excellent targets for ALMA and for next-generation telescopes such as the James Webb Space Telescope.

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It takes a supercluster to raise a galaxy

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316010280 ◽

2014 ◽

Vol 11 (S308) ◽

pp. 412-415

Author(s):

Heidi Lietzen ◽

Maret Einasto

Keyword(s):

Large Scale ◽

Spiral Galaxies ◽

Local Environment ◽

Elliptical Galaxies ◽

Groups Of Galaxies ◽

Star Forming ◽

Blue Star ◽

Galaxy Populations ◽

Filament Type

AbstractThe properties of galaxies depend on their environment: red, passive elliptical galaxies are usually located in denser environments than blue, star-forming spiral galaxies. This difference in galaxy populations can be detected at all scales from groups of galaxies to superclusters. In this paper, we will discuss the effect of the large-scale environment on galaxies. Our results suggest that galaxies in superclusters are more likely to be passive than galaxies in voids even when they belong to groups with the same richness. In addition, the galaxies in superclusters are also affected by the morphology of the supercluster: filament-type superclusters contain relatively more red, passive galaxies than spider-type superclusters. These results suggest that the evolution of a galaxy is not determined by its local environment alone, but the large-scale environment also affects.

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Bubble mapping with the Square Kilometre Array – I. Detecting galaxies with Euclid, JWST, WFIRST, and ELT within ionized bubbles in the intergalactic medium at z > 6

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa098 ◽

2020 ◽

Vol 493 (1) ◽

pp. 855-870

Author(s):

Erik Zackrisson ◽

Suman Majumdar ◽

Rajesh Mondal ◽

Christian Binggeli ◽

Martin Sahlén ◽

...

Keyword(s):

Near Infrared ◽

Intergalactic Medium ◽

Detection Threshold ◽

Line Of Sight ◽

Bubble Volume ◽

Square Kilometre Array ◽

Star Forming ◽

Multiband Imaging ◽

Galaxy Populations ◽

Infrared Telescopes

ABSTRACT The Square Kilometre Array (SKA) is expected to provide the first tomographic observations of the neutral intergalactic medium at redshifts z > 6 and pinpoint the locations of individual ionized bubbles during early stages of cosmic reionization. In scenarios where star-forming galaxies provide most of the ionizing photons required for cosmic reionization, one expects the first ionized bubbles to be centred on overdensities of such galaxies. Here, we model the properties of galaxy populations within isolated, ionized bubbles that SKA-1 should be able to resolve at z ≈ 7–10, and explore the prospects for galaxy counts within such structures with various upcoming near-infrared telescopes. We find that, for the bubbles that are within reach of SKA-1 tomography, the bubble volume is closely tied to the number of ionizing photons that have escaped from the galaxies within. In the case of galaxy-dominated reionization, galaxies are expected to turn up above the spectroscopic detection threshold of JWST and ELT in even the smallest resolvable bubbles at z ≤ 10. The prospects of detecting galaxies within these structures in purely photometric surveys with Euclid, WFIRST, JWST, or ELT are also discussed. While spectroscopy is preferable towards the end of reionization to provide a robust sample of bubble members, multiband imaging may be a competitive option for bubbles at z ≈ 10, due to the very small number of line-of-sight interlopers expected at these redshifts.

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AGN-host connection at 0.5 < z < 2.5: A rapid evolution of AGN fraction in red galaxies during the last 10 Gyr

Astronomy and Astrophysics ◽

10.1051/0004-6361/201526645 ◽

2017 ◽

Vol 601 ◽

pp. A63 ◽

Cited By ~ 26

Author(s):

Tao Wang ◽

D. Elbaz ◽

D. M. Alexander ◽

Y. Q. Xue ◽

J. M. Gabor ◽

...

Keyword(s):

High Redshift ◽

Rapid Evolution ◽

Far Infrared ◽

Stellar Mass ◽

Power Law Distribution ◽

X Ray ◽

Star Forming ◽

Blue Galaxies ◽

Galaxy Populations ◽

Red Galaxies

We explore the dependence of the incidence of moderate-luminosity (L0.5−8 keV = 1041.9−43.7 erg s-1) active galactic nuclei (AGNs) and the distribution of their accretion rates on host color at 0.5 <z < 2.5. Based on the deepest X-ray and UV-to-far-infrared data in the two The Great Observatories Origins Deep Survey (GOODS) fields, we identify 221 AGNs within a mass-complete parent galaxy sample down to M∗ > 1010 M⊙. We use extinction-corrected rest-frame U−V colors to divide both AGN hosts and non-AGN galaxies into red sequence (red), green valley (green), and blue cloud (blue) populations. We find that the fraction of galaxies hosting an AGN at fixed X-ray luminosity increases with stellar mass and redshift for all the three galaxy populations, independent of their colors. However, both the AGN fraction at fixed stellar mass and its evolution with redshift are clearly dependent on host colors. Most notably, red galaxies have the lowest AGN fraction (~5%) at z ~ 1 yet with most rapid evolution with redshift, increasing by a factor of ~5 (24%) at z ~ 2. Green galaxies exhibit the highest AGN fraction across all redshifts, which is most pronounced at z ~ 2 with more than half of them hosting an AGN at M∗ > 1010.6 M⊙. Together with the high AGN fraction in red galaxies at z ~ 2, this indicates that (X-ray) AGNs could be important in both transforming (quenching) star-forming galaxies into quiescent ones and subsequently maintaining their quiescence at high redshift. Furthermore, consistent with previous studies at lower redshifts, we show that the probability of hosting an AGN for the total galaxy population can be characterized by a universal Eddington ratio (as approximated by LX/M∗) distribution (p(λEdd) ~ λEdd-0.4), which is independent on host mass. Yet consistent with their different AGN fractions, galaxies with different colors appear to also have different p(λEdd) with red galaxies exhibiting more rapid redshift evolution compared with that for green and blue galaxies. Evidence for a steeper power-law distribution of p(λEdd) in red galaxies (p(λEdd) ~ λEdd-0.6) is also presented, though larger samples are needed to confirm. These results suggest that the AGN accretion or the growth of supermassive black holes is related to their host properties, and may also influence their hosts in a different mode dependent on the host color.

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AMICO galaxy clusters in KiDS-DR3: Evolution of the luminosity function between z = 0.1 and z = 0.8

Astronomy and Astrophysics ◽

10.1051/0004-6361/202039259 ◽

2020 ◽

Vol 645 ◽

pp. A9

Author(s):

E. Puddu ◽

M. Radovich ◽

M. Sereno ◽

S. Bardelli ◽

M. Maturi ◽

...

Keyword(s):

Luminosity Function ◽

Total Population ◽

Mass Range ◽

Density Parameter ◽

Redshift Range ◽

Star Forming ◽

Cluster Sample ◽

The Rich ◽

Galaxy Populations ◽

Blue Galaxy

Aims. By means of the r-band luminosity function (LF) of galaxies in a sample of about 4000 clusters detected by the cluster finder AMICO in the KiDS-DR3 area of about 400 deg2, we studied the evolution with richness and redshift of the passive evolving (red), star-forming (blue), and total galaxy populations. This analysis was performed for clusters in the redshift range [0.1, 0.8] and in the mass range [1013 M⊙, 1015 M⊙]. Methods. To compute LFs, we binned the luminosity distribution in magnitude and statistically subtracted the background. Then, we divided the cluster sample in bins of both redshift and richness/mass. We stacked LF counts in each 2D bin for the total, red, and blue galaxy populations; finally, we fitted the stacked LF with a Schechter function and studied the trend of its parameters with redshift and richness/mass. Results. We found a passive evolution with z for the bright part of the LF for the red and total populations and no significant trends for the faint galaxies. The mass/richness dependence is clear for the density parameter Φ⋆, increasing with richness, and for the total population faint end, which is shallower in the rich clusters.

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The XXL Survey

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834970 ◽

2019 ◽

Vol 625 ◽

pp. A112 ◽

Cited By ~ 6

Author(s):

V. Guglielmo ◽

B. M. Poggianti ◽

B. Vulcani ◽

S. Maurogordato ◽

J. Fritz ◽

...

Keyword(s):

Star Formation ◽

Stellar Population ◽

Main Sequence ◽

Formation Rate ◽

Local Environment ◽

Star Forming ◽

Blue Galaxies ◽

Galaxy Populations ◽

Definition Of ◽

Star Formation Histories

Exploiting a sample of galaxies drawn from the XXL-North multiwavelength survey, we present an analysis of the stellar population properties of galaxies at 0.1 ≤ z ≤ 0.5, by studying galaxy fractions and the star formation rate (SFR)–stellar mass (M⋆) relation. Furthermore, we exploit and compare two parametrisations of environment. When adopting a definition of “global” environment, we consider separately cluster virial (r ≤ 1r200) and outer (1r200 < r ≤ 3r200) members and field galaxies. We also distinguish between galaxies that belong or do not belong to superclusters, but never find systematic differences between the two subgroups. When considering the “local” environment, we take into account the projected number density of galaxies in a fixed aperture of 1 Mpc in the sky. We find that regardless of the environmental definition adopted, the fraction of blue or star-forming galaxies is the highest in the field or least dense regions and the lowest in the virial regions of clusters or highest densities. Furthermore, the fraction of star-forming galaxies is higher than the fraction of blue galaxies, regardless of the environment. This result is particularly evident in the virial cluster regions, most likely reflecting the different star formation histories of galaxies in different environments. Also the overall SFR–M⋆ relation does not seem to depend on the parametrisation adopted. Nonetheless, the two definitions of environment lead to different results as far as the fraction of galaxies in transition between the star-forming main sequence and the quenched regime is concerned. In fact, using the local environment the fraction of galaxies below the main sequence is similar at low and high densities, whereas in clusters (and especially within the virial radii) a population with reduced SFR with respect to the field is observed. Our results show that the two parametrisations adopted to describe the environment have different physical meanings, i.e. are intrinsically related to different physical processes acting on galaxy populations and are able to probe different physical scales.

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