scholarly journals Galaxy Evolution in a Pilot Survey up toz=1and CDM Halos

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
E. Giraud ◽  
J. Melnick ◽  
Q.-S. Gu ◽  
H. Quintana ◽  
F. Selman ◽  
...  
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Emission Lines ◽  
Pencil Beam ◽  
Spectral Evolution ◽  
Cosmological Time ◽  
Emission Line Galaxies ◽  
Individual Galaxy

We study spectral evolution of galaxies in a magnitude limited sample of 550 galaxies fromz=1down toz=0.3on a pencil beam of≈10′×10′. We concentrate on the large apparent cosmological structures along the line of sight, and we bin our individual galaxy spectra to obtain representative high S/N spectra based upon these structures. We divide the resulting average spectra in three groups to facilitate the analysis:galaxies with pure absorption line spectra, galaxies with emission lines and blue continua, and galaxies with emission lines and red continua. We revisit the question of downsizing in emission-line galaxies betweenz=0.9andz=0.45in our pencil-beam and find the following results: strong star formation in emission line galaxies, aging in emission line galaxies, and aging in absorption systems, are shifting from bright to faint systems as cosmological time increases. Each redshift bin is repopulated in new starbursts. Therefore at redshiftsz⩽1galaxy formation is downsizing both in luminosity and number density. Our observations indicate that atz⩽1star formation and hierarchical structure formation of CDM halos are not in phase.

scholarly journals Low Metallicity Galaxies at z ~ 0.7: Keys to the Origins of Metallicity Scaling Laws

2008 ◽  
Vol 4 (S255) ◽  
pp. 397-401
Author(s):  
David J. Rosario ◽  
Carlos Hoyos ◽  
David Koo ◽  
Andrew Phillips
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Galaxy Evolution ◽  
Scaling Laws ◽  
Temperature Sensitive ◽  
Star Forming ◽  
Low Metallicity ◽  
Emission Line Galaxies ◽  
Halo Masses ◽  
Stellar Masses

AbstractWe present a study of remarkably luminous and unique dwarf galaxies at redshifts of 0.5 < z < 0.7, selected from the DEEP2 Galaxy Redshift survey by the presence of the temperature sensitive [OIII]λ4363 emission line. Measurements of this important auroral line, as well as other strong oxygen lines, allow us to estimate the integrated oxygen abundances of these galaxies accurately without being subject to the degeneracy inherent in the standard R23 system used by most studies. [O/H] estimates range between 1/5–1/10 of the solar value. Not surprisingly, these systems are exceedingly rare and hence represent a population that is not typically present in local surveys such as SDSS, or smaller volume deep surveys such as GOODS.Our low-metallicity galaxies exhibit many unprecedented characteristics. With B-band luminosities close to L*, thse dwarfs lie significantly away from the luminosity-metallicity relationships of both local and intermediate redshift star-forming galaxies. Using stellar masses determined from optical and NIR photometry, we show that they also deviate strongly from corresponding mass-metallicity relationships. Their specific star formation rates are high, implying a significant burst of recent star formation. A campaign of high resolution spectroscopic follow-up shows that our galaxies have dynamical properties similar to local HII and compact emission line galaxies, but mass-to-light ratios that are much higher than average star-forming dwarfs.The low metallicities, high specific star formation rates, and small halo masses of our galaxies mark them as lower redshift analogs of Lyman-Break galaxies, which, at z ~ 2 are evolving onto the metallicity sequence that we observe in the galaxy population of today. In this sense, these systems offer fundamental insights into the physical processes and regulatory mechanisms that drive galaxy evolution in that epoch of major star formation and stellar mass assembly.

scholarly journals Compact Galaxies at Z = 0.2-1.3: Implications for Galaxy Evolution and the Star Formation History of the Universe

1998 ◽  
Vol 11 (1) ◽  
pp. 147-148
Author(s):  
R. Guzman ◽  
A.C. Phillips ◽  
J. Gallego ◽  
D.C. Koo
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Galaxy Evolution ◽  
Young Star ◽  
Star Formation History ◽  
Star Forming ◽  
V Band ◽  
Low Mass ◽  
Compact Galaxies ◽  
Emission Line Galaxies

Abstract We study the global properties of 51 compact field galaxies with redshifts z ~ 0.2 - 1.3 and apparent magnitudes I814 < 23.74 in the flanking fields of the Hubble Deep Field. All these galaxies have angular half-light radii re < 0.5 arcsec. Keck spectra covering ~4000-9000 Å, combined with HST І814 images and Keck V-band images, were used to derive redshifts, V606 - I814 colors, absolute blue magnitudes (MB), linear half-light radii (Re), blue average surface brightnesses within Re (SBe), velocity widths (σ), virial masses (M), mass-to-light ratios (M/L), excitations (O[III]/Hβ), and star formation rates (SFR). The results of this study can be summarized as follows: (i):Only 12% of the 51 compact galaxies have absorption-line dominated spectra, while 88% show strong, narrow emission lines, similar to the so-called CNELGs (e.g., Koo, this volume).(ii):Despite being very luminous (i.e., LB ~ L*; see figure la), compact emission-line galaxies are low-mass stellar sytems (i.e., M ≤ 1010 Mʘ, typically; see figure lb).(iii):Roughly 60% of the compact emission-line galaxies have colors, sizes, surface brightnesses, luminosities, velocity widths, excitations, star formation rates, and mass-to-light ratios characteristic of young, star-forming HII galaxies (see figures 1 and 2). The remaining 40% form a more heterogeneous class of evolved starbursts, similar to local disk starburst galaxies.(iv):Without additional star formation, galaxy evolution models predict that HII-like distant compacts will fade to resemble today’s spheroidal galaxies such as NGC 205 (Koo, this volume).

scholarly journals Emission Line Galaxies at 1 < z < 1.5

1999 ◽  
Vol 186 ◽  
pp. 467-470
Author(s):  
K. Glazebrook ◽  
R.G. Abraham ◽  
C.A. Blake
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Emission Lines ◽  
Redshift Surveys ◽  
First Results ◽  
History Of ◽  
Emission Line Galaxies ◽  
Hubble Deep Field

In this paper we wish to introduce the first results on two new projects aimed at detecting emission lines in galaxies at z > 1. There are two primary motivations for doing this: Firstly to try and measure the cosmic star-formation rate at these redshifts. The combination of z < 1 redshift surveys and the discovery of the z ~ 3 Hubble Deep Field ultraviolet dropout objects has led to a ‘first draft’ history of the cosmic SFR (Fig. 1). These results are based on UV continuum fluxes, it is highly desirably to confirm these studies with line diagnostics and extend the work to the redshift of the inferred peak (z ~ 1.5).

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 In pursuit of giants

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.

scholarly journals Do quasars evolve over cosmological time scales?

1986 ◽  
Vol 119 ◽  
pp. 439-445
Author(s):  
E.J. Wampler ◽  
D. Ponz
Keyword(s):  
Emission Line ◽  
Time Scales ◽  
Line Strength ◽  
Schmidt Telescope ◽  
Spectral Evolution ◽  
General Correlation ◽  
Cosmological Time ◽  
Systematic Biases ◽  
Evolution Laws ◽  
Lower Luminosity

Systematic biases that are redshift dependent can influence the optical discovery of quasars and the evolution laws derived from counts of quasars. New data and their interpretation for quasars brighter than MB = −24 in the Palomar Bright Quasar Survey (BQS) (Schmidt and Green, 1983) are consistent with no evolution. A comparison of BQS quasars with the brightest quasars from the CTIO Schmidt Telescope Survey (Osmer and Smith, 1980) shows that if qo is near zero, the co-moving density of bright quasars in a Friedmann cosmology is about 15 times higher for the CTIO survey quasars (mean z ≈ 2.8) than for the BQS quasars (mean z ≈ 1.8). In this case spectral evolution is also required since the CTIO quasars have stronger CIV λ1548 lines than the BQS quasars of similar luminosity. Alternatively, if qO is taken to be near 1, the CTIO survey quasars would then have lower luminosity than the BQS quasars and these data would be consistent with no evolution. Strong CIV λ1548 lines for the CTIO quasars would then fit the general correlation between absolute quasar luminosity and emission line strength (Wampler, Gaskell, Burke and Baldwin, 1984).

scholarly journals Prediction of H α and [O iii] emission line galaxy number counts for future galaxy redshift surveys

2019 ◽  
Vol 490 (3) ◽  
pp. 3667-3678 ◽  
Author(s):  
Zhongxu Zhai ◽  
Andrew Benson ◽  
Yun Wang ◽  
Gustavo Yepes ◽  
Chia-Hsun Chuang
Keyword(s):  
Emission Line ◽  
Galaxy Formation ◽  
Luminosity Function ◽  
Large Scale ◽  
High Redshift ◽  
Flux Ratio ◽  
Formation Model ◽  
Line Flux ◽  
Emission Line Galaxies ◽  
Number Counts

ABSTRACT We perform a simulation with Galacticus, a semi-analytical galaxy formation model, to predict the number counts of H α and [O iii] emitting galaxies. With a state-of-the-art N-body simulation, UNIT, we first calibrate Galacticus with the current observation of H α luminosity function. The resulting model coupled with a dust attenuation model, can reproduce the current observations, including the H α luminosity function from HiZELS and number density from WISP. We extrapolate the model prediction to higher redshift and the result is found to be consistent with previous investigations. We then use the same galaxy formation model to predict the number counts for [O iii] emitting galaxies. The result provides further validation of our galaxy formation model and dust model. We present number counts of H α and [O iii] emission line galaxies for three different line flux limits: 5 × 10−17erg s−1 cm−2, 1 × 10−16 erg s−1 cm−2 (6.5σ nominal depth for WFIRST GRS), and 2 × 10−16 erg s−1 cm−2 (3.5σ depth of Euclid GRS). At redshift 2 &lt; z &lt; 3, our model predicts that WFIRST can observe hundreds of [O iii] emission line galaxies per square degree with a line flux limit of 1 × 10−16 erg s−1 cm−2. This will provide accurate measurement of large-scale structure to probe dark energy over a huge cosmic volume to an unprecedented high redshift. Finally, we compare the flux ratio of H α/[O iii] within the redshift range of 0 &lt; z &lt; 3. Our results show the known trend of increasing H α/[O iii] flux ratio with H α flux at low redshift, which becomes a weaker trend at higher redshifts.

scholarly journals Slitless Spectroscopy by Photographic and CCD Detectors Across Large Fields

1994 ◽  
Vol 161 ◽  
pp. 709-714
Author(s):  
G. Comte ◽  
C. Surace
Keyword(s):  
Emission Line ◽  
Emission Lines ◽  
Photographic Emulsion ◽  
Subsequent Reduction ◽  
Schmidt Telescope ◽  
Ccd Array ◽  
Objective Prism ◽  
Emission Line Galaxies ◽  
Ccd Detectors

We present a new survey of emission line galaxies, performed with the ESO 1 m Schmidt telescope equipped with the 4° objective prism using IIIa-J photographic emulsion. The plates are digitized with the MAMA microdensitometer. A subsequent reduction of the block scans gives redshifts with a mean accuracy of 160 km/s−1, and spectrophotometric measurements of the intensity and equivalent widths of the principal emission lines. A brief discussion is given of the possible extension of quantitative reduction of slitless spectroscopy to archive plates and future large CCD array frames.

scholarly journals Study of a Complete Sample of Hα Emission–Line Galaxies from the UCM Survey

1996 ◽  
Vol 171 ◽  
pp. 380-380 ◽  
Author(s):  
J. Gallego ◽  
J. Zamorano ◽  
M. Rego ◽  
A.G. Vitores ◽  
O. Alonso
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Energy Output ◽  
University Of Michigan ◽  
Complete Sample ◽  
Star Forming ◽  
The Galaxy ◽  
Hα Emission ◽  
Emission Line Galaxies ◽  
Galaxy Population

The Universidad Complutense de Madrid survey is a long-term project with the aim of finding and analyzing star forming galaxies using the Hα line as the tracer for star formation processes. In order to obtain a representative and complete sample of the population detected, spectroscopic observations were carried out for the full sample of Hα emission-line galaxy (ELG) candidates of the UCM lists 1 and 2. The ELGs types most commonly found (47%) are intermediate to low-luminosity objects with a very intense star-formation region which dominates the optical energy output of the galaxy. This kind of ELGs is similar to the galaxy population detected in the blue objective-prism surveys. And what is more important, a second population (43%) of star-forming galaxies with low ionization or high extinction properties has been found. This ELGs group is detected neither in the blue (University of Michigan survey, Case survey) nor in other surveys (Kiso, IRAS, Markarian) using other selection techniques.

scholarly journals The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: exploring the halo occupation distribution model for emission line galaxies

2020 ◽  
Vol 499 (4) ◽  
pp. 5486-5507 ◽  
Author(s):  
S Avila ◽  
V Gonzalez-Perez ◽  
F G Mohammad ◽  
A de Mattia ◽  
C Zhao ◽  
...  
Keyword(s):  
Emission Line ◽  
Galaxy Formation ◽  
Distribution Model ◽  
Galaxy Formation And Evolution ◽  
Formation And Evolution ◽  
Physical Effects ◽  
Emission Line Galaxies ◽  
Halo Masses ◽  
The Impact ◽  
Halo Occupation Distribution

ABSTRACT We study the modelling of the halo occupation distribution (HOD) for the eBOSS DR16 emission line galaxies (ELGs). Motivated by previous theoretical and observational studies, we consider different physical effects that can change how ELGs populate haloes. We explore the shape of the average HOD, the fraction of satellite galaxies, their probability distribution function (PDF), and their density and velocity profiles. Our baseline HOD shape was fitted to a semi-analytical model of galaxy formation and evolution, with a decaying occupation of central ELGs at high halo masses. We consider Poisson and sub/super-Poissonian PDFs for satellite assignment. We model both Navarro–Frenk–White and particle profiles for satellite positions, also allowing for decreased concentrations. We model velocities with the virial theorem and particle velocity distributions. Additionally, we introduce a velocity bias and a net infall velocity. We study how these choices impact the clustering statistics while keeping the number density and bias fixed to that from eBOSS ELGs. The projected correlation function, wp, captures most of the effects from the PDF and satellites profile. The quadrupole, ξ2, captures most of the effects coming from the velocity profile. We find that the impact of the mean HOD shape is subdominant relative to the rest of choices. We fit the clustering of the eBOSS DR16 ELG data under different combinations of the above assumptions. The catalogues presented here have been analysed in companion papers, showing that eBOSS RSD+BAO measurements are insensitive to the details of galaxy physics considered here. These catalogues are made publicly available.

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