scholarly journals Infall models of galaxy evolution: a solution to the redshift distribution problem?

1993 ◽  
Vol 263 (1) ◽  
pp. 86-92 ◽  
Author(s):  
S. Phillipps
Keyword(s):  
Galaxy Evolution ◽  
Distribution Problem ◽  
Redshift Distribution

scholarly journals Towards a census of high-redshift dusty galaxies with Herschel

2018 ◽  
Vol 614 ◽  
pp. A33 ◽  
Author(s):  
D. Donevski ◽  
V. Buat ◽  
F. Boone ◽  
C. Pappalardo ◽  
M. Bethermin ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Far Infrared ◽  
Virgo Cluster ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
Redshift Distribution ◽  
Star Forming

Context. Over the last decade a large number of dusty star-forming galaxies has been discovered up to redshift z = 2 − 3 and recent studies have attempted to push the highly confused Herschel SPIRE surveys beyond that distance. To search for z ≥ 4 galaxies they often consider the sources with fluxes rising from 250 μm to 500 μm (so-called “500 μm-risers”). Herschel surveys offer a unique opportunity to efficiently select a large number of these rare objects, and thus gain insight into the prodigious star-forming activity that takes place in the very distant Universe. Aims. We aim to implement a novel method to obtain a statistical sample of 500 μm-risers and fully evaluate our selection inspecting different models of galaxy evolution. Methods. We consider one of the largest and deepest Herschel surveys, the Herschel Virgo Cluster Survey. We develop a novel selection algorithm which links the source extraction and spectral energy distribution fitting. To fully quantify selection biases we make end-to-end simulations including clustering and lensing. Results. We select 133 500 μm-risers over 55 deg2, imposing the criteria: S500 > S350 > S250, S250 > 13.2 mJy and S500 > 30 mJy. Differential number counts are in fairly good agreement with models, displaying a better match than other existing samples. The estimated fraction of strongly lensed sources is 24+6-5% based on models. Conclusions. We present the faintest sample of 500 μm-risers down to S250 = 13.2 mJy. We show that noise and strong lensing have an important impact on measured counts and redshift distribution of selected sources. We estimate the flux-corrected star formation rate density at 4 < z < 5 with the 500 μm-risers and find it to be close to the total value measured in far-infrared. This indicates that colour selection is not a limiting effect to search for the most massive, dusty z > 4 sources.

scholarly journals Reproducing sub-millimetre galaxy number counts with cosmological hydrodynamic simulations

2021 ◽  
Author(s):  
Christopher C Lovell ◽  
James E Geach ◽  
Romeel Davé ◽  
Desika Narayanan ◽  
Qi Li
Keyword(s):  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Formation Rate ◽  
Small Contribution ◽  
Redshift Distribution ◽  
Hydrodynamic Simulation ◽  
Hydrodynamic Simulations ◽  
Multiple Components ◽  
Number Counts ◽  
Good Agreement

Abstract Matching the number counts of high-z sub-millimetre-selected galaxies (SMGs) has been a long standing problem for galaxy formation models. In this paper, we use 3D dust radiative transfer to model the sub-mm emission from galaxies in the Simba cosmological hydrodynamic simulations, and compare predictions to the latest single-dish observational constraints on the abundance of 850 μm-selected sources. We find good agreement with the shape of the integrated 850 μm luminosity function, and the normalisation is within 0.25 dex at &gt;3 mJy, unprecedented for a fully cosmological hydrodynamic simulation, along with good agreement in the redshift distribution of bright SMGs. The agreement is driven primarily by Simba’s good match to infrared measures of the star formation rate (SFR) function between z = 2 − 4 at high SFRs. Also important is the self-consistent on-the-fly dust model in Simba, which predicts, on average, higher dust masses (by up to a factor of 2.5) compared to using a fixed dust-to-metals ratio of 0.3. We construct a lightcone to investigate the effect of far-field blending, and find that 52% of sources are blends of multiple components, which makes a small contribution to the normalisation of the bright-end of the number counts. We provide new fits to the 850 μm luminosity as a function of SFR and dust mass. Our results demonstrate that solutions to the discrepancy between sub-mm counts in simulations and observations, such as a top-heavy IMF, are unnecessary, and that sub-millimetre-bright phases are a natural consequence of massive galaxy evolution.

scholarly journals The VANDELS ESO public spectroscopic survey: Observations and first data release

2018 ◽  
Vol 616 ◽  
pp. A174 ◽  
Author(s):  
L. Pentericci ◽  
R. J. McLure ◽  
B. Garilli ◽  
O. Cucciati ◽  
P. Franzetti ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Spectroscopic Data ◽  
Signal To Noise Ratio ◽  
High Redshift ◽  
Measurement Procedure ◽  
Integration Time ◽  
High Signal ◽  
Redshift Distribution ◽  
Data Set ◽  
Data Release

This paper describes the observations and the first data release (DR1) of the ESO public spectroscopic survey “VANDELS, a deep VIMOS survey of the CANDELS CDFS and UDS fields”. The main targets of VANDELS are star-forming galaxies at redshift 2.4 < z < 5.5, an epoch when the Universe had not yet reached 20% of its current age, and massive passive galaxies in the range 1 < z < 2.5. By adopting a strategy of ultra-long exposure times, ranging from a minimum of 20 h to a maximum of 80 h per source, VANDELS is specifically designed to be the deepest-ever spectroscopic survey of the high-redshift Universe. Exploiting the red sensitivity of the refurbished VIMOS spectrograph, the survey is obtaining ultra-deep optical spectroscopy covering the wavelength range 4800–10 000 Å with a sufficiently high signal-to-noise ratio to investigate the astrophysics of high-redshift galaxy evolution via detailed absorption line studies of well-defined samples of high-redshift galaxies. VANDELS-DR1 is the release of all medium-resolution spectroscopic data obtained during the first season of observations, on a 0.2 square degree area centered around the CANDELS-CDFS (Chandra deep-field south) and CANDELS-UDS (ultra-deep survey) areas. It includes data for all galaxies for which the total (or half of the total) scheduled integration time was completed. The DR1 contains 879 individual objects, approximately half in each of the two fields, that have a measured redshift, with the highest reliable redshifts reaching zspec ~ 6. In DR1 we include fully wavelength-calibrated and flux-calibrated 1D spectra, the associated error spectrum and sky spectrum, and the associated wavelength-calibrated 2D spectra. We also provide a catalog with the essential galaxy parameters, including spectroscopic redshifts and redshift quality flags measured by the collaboration. We present the survey layout and observations, the data reduction and redshift measurement procedure, and the general properties of the VANDELS-DR1 sample. In particular, we discuss the spectroscopic redshift distribution and the accuracy of the photometricredshifts for each individual target category, and we provide some examples of data products for the various target typesand the different quality flags. All VANDELS-DR1 data are publicly available and can be retrieved from the ESO archive. Two further data releases are foreseen in the next two years, and a final data release is currently scheduled for June 2020, which will include an improved rereduction of the entire spectroscopic data set.

scholarly journals Galaxy Evolution Traced by Multiple Galaxies from the BIG Sample

2006 ◽  
Vol 2 (S235) ◽  
pp. 225-225 ◽  
Author(s):  
Areg M. Mickaelian
Keyword(s):  
Galaxy Evolution ◽  
Special Astrophysical Observatory ◽  
Redshift Distribution ◽  
Ir Radiation ◽  
Galaxy Interactions ◽  
Or Groups ◽  
The Galaxy ◽  
Redshift Survey ◽  
Optical Identifications

AbstractOptical identifications of all IRAS PSC sources at high galactic latitudes by means of the First Byurakan Survey (FBS) in the area with +61° < δ < +90° at galactic latitudes |b|>15° have been carried out with a total surface of 1487 deg2. 1577 sources have been optically identified, 1178 sources corresponding to galaxies. The BIG sample (Byurakan-IRAS Galaxies) was constructed of 1178 newly identified galaxies and 789 other IRAS galaxies in the same area, known before, altogether 1967 galaxies. Studies of the BIG objects include: spectroscopic follow-up for the brighter (<18m) objects; discovery and study of new AGN; discovery and study of new ULIRGs; deep imagery of the most interesting objects and the “empty fields”; 2D spectroscopy of interacting/merging systems; search for obscured IRAS galaxies (with the Spitzer Space Telescope), etc. The BIG objects are a rich source for new AGN, high-luminosity IR galaxies (hence, starburst activity), and interacting/merging systems. All these phenomena are crucial for understanding the galaxy evolution and their interrelation, as well as the triggering of the powerful IR radiation. In frame of the redshift survey of these galaxies, spectroscopic observations have been carried out for the BIG objects (including the pairs and multiples) by means of the Byurakan Astrophysical Observatory (BAO, Armenia) 2.6m, Special Astrophysical Observatory (SAO, Russia) 6m, and Observatoire de Haute Provence (OHP, France) 1.93m telescopes. It is shown that, without an exception, all double/multiple BIG systems are physical pairs or groups, and they are mostly interacting and/or merging systems. From the high IR luminosities derived from the observations, one can conclude that perhaps the ULIRG/HLIRG phenomenon is connected with galaxy interactions/merging. We find an evolution in luminosity function of these objects with respect to their redshift distribution.Existence of AGN among the multiple BIG objects provides a chance for study of the galaxy evolution in sense of interrelationship between the three phenomena: starburst, interactions/merging, and nuclear activity. We have shown (Mickaelian et al. 2001) that the maximum IR luminosity of a single spiral galaxy may not be larger than 1012 Solar luminosities. Hence, all high-L IRAS galaxies are interacting pairs/multiples or mergers. But what is the relation of the active nucleus to the starburst (i.e. IR) activity?

scholarly journals Large High Redshift Spectroscopic Surveys

2010 ◽  
Vol 6 (S277) ◽  
pp. 121-127
Author(s):  
Olivier Le Fèvre
Keyword(s):  
Galaxy Evolution ◽  
Mass Density ◽  
High Redshift ◽  
Sample Selection ◽  
Global Perspective ◽  
Observational Cosmology ◽  
Wide Field ◽  
Redshift Distribution ◽  
Redshift Surveys ◽  
Mass Assembly

AbstractDeep spectroscopic redshift surveys have become an important tool for observational cosmology, supported by a new generation of wide field multi-object spectrographs. They bring high redshift accuracy and a wealth of spectral features necessary for precision astrophysics and have led to the outstanding progress in our understanding of the different phases of galaxy evolution. The measurement of the evolution of volume quantities like the luminosity and mass functions or the correlation function, has enabled a deep insight into galaxy evolution since redshifts z ≃ 7. The redshift distribution N(z,m) is a basic property but is still difficult to be reproduced by models. We have now a global perspective on the history of star formation with a peak at z = 1−2 but the decline in SFRD at higher redshifts is still to be confirmed. The evolution of the stellar mass density with a fast growth in red passive galaxies between z = 2 and z = 1 is well established. The contribution to galaxy mass assembly of key physical processes like merging or cold accretion is now well documented. However, the pioneer measurements at the high redshift end z > > 1 remain to be consolidated with robust sample selection and statistical accuracy from large spectroscopic redshift surveys, a challenge for the years to come.

Central kiloparsec of NGC 1326 observed with SINFONI

2020 ◽  
Vol 638 ◽  
pp. A53
Author(s):  
Nastaran Fazeli ◽  
Gerold Busch ◽  
Andreas Eckart ◽  
Françoise Combes ◽  
Persis Misquitta ◽  
...  
Keyword(s):  
Black Hole ◽  
Galaxy Evolution ◽  
Near Infrared ◽  
Velocity Fields ◽  
Molecular Gas ◽  
Nearby Galaxy ◽  
Stellar Content ◽  
Stellar Rotation ◽  
Supermassive Black Hole ◽  
Integral Field Spectrograph

Gas inflow processes in the vicinity of galactic nuclei play a crucial role in galaxy evolution and supermassive black hole growth. Exploring the central kiloparsec of galaxies is essential to shed more light on this subject. We present near-infrared H- and K-band results of the nuclear region of the nearby galaxy NGC 1326, observed with the integral-field spectrograph SINFONI mounted on the Very Large Telescope. The field of view covers 9″ × 9″ (650 × 650 pc2). Our work is concentrated on excitation conditions, morphology, and stellar content. The nucleus of NGC 1326 was classified as a LINER, however in our data we observed an absence of ionised gas emission in the central r ∼ 3″. We studied the morphology by analysing the distribution of ionised and molecular gas, and thereby detected an elliptically shaped, circum-nuclear star-forming ring at a mean radius of 300 pc. We estimate the starburst regions in the ring to be young with dominating ages of < 10 Myr. The molecular gas distribution also reveals an elongated east to west central structure about 3″ in radius, where gas is excited by slow or mild shock mechanisms. We calculate the ionised gas mass of 8 × 105 M⊙ completely concentrated in the nuclear ring and the warm molecular gas mass of 187 M⊙, from which half is concentrated in the ring and the other half in the elongated central structure. The stellar velocity fields show pure rotation in the plane of the galaxy. The gas velocity fields show similar rotation in the ring, but in the central elongated H2 structure they show much higher amplitudes and indications of further deviation from the stellar rotation in the central 1″ aperture. We suggest that the central 6″ elongated H2 structure might be a fast-rotating central disc. The CO(3–2) emission observations with the Atacama Large Millimeter/submillimeter Array reveal a central 1″ torus. In the central 1″ of the H2 velocity field and residual maps, we find indications for a further decoupled structure closer to a nuclear disc, which could be identified with the torus surrounding the supermassive black hole.

Statistical Studies on Galaxy Evolution from IR Observations

2002 ◽  
Vol 4 ◽  
pp. 375-375
Author(s):  
T. T. Takeuchi ◽  
T. T. Ishii ◽  
T. Totani
Keyword(s):  
Galaxy Evolution ◽  
Statistical Studies

The First Galaxies in the Universe

2013 ◽  
Author(s):  
Abraham Loeb ◽  
Steven R. Furlanetto
Keyword(s):  
Galaxy Evolution ◽  
Big Bang ◽  
First Stars ◽  
Distant Galaxies ◽  
Formation And Evolution ◽  
Early Galaxies ◽  
First Galaxies ◽  
Large Telescopes ◽  
New Generation ◽  
The Big Bang

This book provides a comprehensive, self-contained introduction to one of the most exciting frontiers in astrophysics today: the quest to understand how the oldest and most distant galaxies in our universe first formed. Until now, most research on this question has been theoretical, but the next few years will bring about a new generation of large telescopes that promise to supply a flood of data about the infant universe during its first billion years after the big bang. This book bridges the gap between theory and observation. It is an invaluable reference for students and researchers on early galaxies. The book starts from basic physical principles before moving on to more advanced material. Topics include the gravitational growth of structure, the intergalactic medium, the formation and evolution of the first stars and black holes, feedback and galaxy evolution, reionization, 21-cm cosmology, and more.

Hubble Sequence: New Light on Galaxy Evolution

Nature ◽  
1970 ◽  
Vol 226 (5251) ◽  
pp. 1091-1092
Author(s):  
Keyword(s):  
Galaxy Evolution ◽  
Hubble Sequence
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