scholarly journals Resolution-independent modelling of environmental effects in semi-analytic models of galaxy formation that include ram-pressure stripping of both hot and cold gas

2016 ◽  
Vol 458 (1) ◽  
pp. 366-378 ◽  
Author(s):  
Yu Luo ◽  
Xi Kang ◽  
Guinevere Kauffmann ◽  
Jian Fu
Keyword(s):  
Galaxy Formation ◽  
Environmental Effects ◽  
Ram Pressure ◽  
Analytic Models ◽  
Cold Gas

Radial resolved galaxy disks models based on semi-analytic models of galaxy formation

2019 ◽  
Vol 15 (S341) ◽  
pp. 273-274
Author(s):  
Jian Fu
Keyword(s):  
Galaxy Formation ◽  
Scaling Relations ◽  
Chemical Enrichment ◽  
Galaxy Disk ◽  
Analytic Models ◽  
Cold Gas

AbstractWe show our work on the L-Galaxies semi-analytic models of galaxy formation, which includes the radial resolved distribution of star, gas, SFR and metallicity on each galaxy disk. The newest version of the codes include the H22-to-HI gas transition prescriptions and the chemical enrichment of various elements. Our revised model can give results on cold gas components, radial metallicity gradients and scaling relations, which can fit the recent observations.

scholarly journals Global H i asymmetries in IllustrisTNG: a diversity of physical processes disturb the cold gas in galaxies

2020 ◽  
Vol 499 (4) ◽  
pp. 5205-5219
Author(s):  
Adam B Watts ◽  
Chris Power ◽  
Barbara Catinella ◽  
Luca Cortese ◽  
Adam R H Stevens
Keyword(s):  
Galaxy Formation ◽  
Atomic Hydrogen ◽  
Physical Processes ◽  
Low Velocity ◽  
Ram Pressure ◽  
Asymmetric Shape ◽  
Satellite Galaxies ◽  
Large Groups ◽  
Disc Galaxies ◽  
Cold Gas

ABSTRACT Observations of the cold neutral atomic hydrogen (H i) in and around disc galaxies have revealed that spatial and kinematic asymmetries are common place, and are reflected in the global H i spectra. We use the TNG100 box from the IllustrisTNG suite of cosmological simulations to study the conditions under which these asymmetries may arise in current theoretical galaxy formation models. We find that more than 50 per cent of the sample has at least a 10 per cent difference in integrated flux between the high- and low-velocity half of the spectrum, thus the typical TNG100 galaxy has an H i profile that is not fully symmetric. We find that satellite galaxies are a more asymmetric population than centrals, consistent with observational results. Using halo mass as a proxy for environment, this trend appears to be driven by the satellite population within the virial radius of haloes more massive than 1013 M⊙, typical of medium/large groups. We show that, while the excess of H i asymmetry in group satellites is likely driven by ram pressure, the bulk of the asymmetric H i profiles observed in TNG100 are driven by physical processes able to affect both the central and satellite populations. Our results highlight how asymmetries are not driven solely by environment, and multiple physical processes can produce the same asymmetric shape in global H i spectra.

scholarly journals The atomic gas in outer disks in semi-analytic models of galaxy formation

2016 ◽  
Vol 11 (S321) ◽  
pp. 131-131
Author(s):  
Jian Fu ◽  
Yu Luo
Keyword(s):  
Galaxy Formation ◽  
Surface Density ◽  
Mass Relation ◽  
Gas Stripping ◽  
Density Region ◽  
Radial Profiles ◽  
Gas Accretion ◽  
Analytic Models ◽  
Gas Component ◽  
Cold Gas

AbstractWe use semi-analytic models of galaxy formation L-Galaxies based on ΛCDM cosmology to study the HI gas component in galaxy outskirts. We adopt the radially-resolved version of the models by Fu et al. (2013), which includes both atomic and molecular gas component in interstellar medium. This model has been recently updated by Luo et al. (2016) to include cold gas stripping in the outer disk regions of the satellite galaxies by ram pressure. In our models, we can perfectly reproduce the HI size-mass relation, which is discovered by Broeils & Rhee (1997) and confirmed by many subsequent observations. In our model, the reason for such tight correlation between HI size and mass is atomic-molecular phase conversion in high gas surface density regions while HI ionization in low gas surface density region, which leads to very narrow distribution of HI mean surface density. The models also reproduce the universal exponential HI radial profiles in galaxy outskirts found by Bluedisk (Wang et al. 2013), which arises from cold gas accretion onto the galaxy disks in exponentially profiles.

scholarly journals The influence of environment on satellite galaxies in the GAEA semi-analytic model

2020 ◽  
Vol 498 (3) ◽  
pp. 4327-4344 ◽  
Author(s):  
Lizhi Xie ◽  
Gabriella De Lucia ◽  
Michaela Hirschmann ◽  
Fabio Fontanot
Keyword(s):  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Analytic Model ◽  
Gas Stripping ◽  
Hot Gas ◽  
Ram Pressure ◽  
Low Mass ◽  
Quenching Mechanisms ◽  
Satellite Galaxies ◽  
Cold Gas

ABSTRACT Reproducing the observed quenched fraction of satellite galaxies has been a long-standing issue for galaxy formation models. We modify the treatment of environmental effects in our state-of-the-art GAlaxy Evolution and Assembly (GAEA) semi-analytic model to improve our modelling of satellite galaxies. Specifically, we implement gradual stripping of hot gas, ram-pressure stripping of cold gas, and an updated algorithm to account for angular momentum exchanges between the gaseous and stellar disc components of model galaxies. Our updated model predicts quenched fractions that are in good agreement with local observational measurements for central and satellite galaxies, and their dependencies on stellar mass and halo mass. We also find consistency between model predictions and observational estimates of quenching times for satellite galaxies, H i, H2 fractions of central galaxies, and deficiencies of H i, H2, SFR of galaxies in cluster haloes. In the framework of our updated model, the dominant quenching mechanisms are hot gas stripping for low-mass satellite galaxies, and AGN feedback for massive satellite galaxies. The ram-pressure stripping of cold gas only affects the quenched fraction in massive haloes with Mh > 1013.5 M⊙, but is needed to reproduce the observed H i deficiencies.

scholarly journals Environmental Effects on Evolution of Cluster Galaxies

2003 ◽  
Vol 208 ◽  
pp. 435-436
Author(s):  
Takashi Okamoto ◽  
Masahiro Nagashima
Keyword(s):  
Star Formation ◽  
Structure Formation ◽  
Hierarchical Structure ◽  
Galaxy Formation ◽  
Environmental Effects ◽  
Formation Model ◽  
Cluster Galaxies ◽  
Hot Gas ◽  
Ram Pressure ◽  
The Hierarchical Structure

Using a combination of a cosmological N-body simulation and a semi-analytic galaxy formation model, we investigate environmental effects on cluster galaxies with the ACDM cosmology. We find that stripping of hot gas from galacitc halos as they infall into larger objects sufficiently suppresses star formation in the cluster and successfully reproduces the observed gradients of SFR when we normalize our model to reproduce the observed properties of local galaxies. Consequently, the effect of ram-pressure stripping of cold gas from galactic disks becomes quite small and it is observationally negligible. Therefore, the deficiency of galaxies with intermediate bulge-to-disk luminosity ratios under the hierarchical structure formation cannot be resolved even if we include the ram-pressure stripping in our modeling.

scholarly journals Effects of environment on the properties of cluster galaxies via ram pressure stripping

2009 ◽  
Vol 5 (H15) ◽  
pp. 294-294
Author(s):  
T. E. Tecce ◽  
S. A. Cora ◽  
P. B. Tissera ◽  
M. G. Abadi
Keyword(s):  
Star Formation ◽  
Galaxy Clusters ◽  
Galaxy Formation ◽  
Gas Content ◽  
Analytic Model ◽  
Cluster Galaxies ◽  
Ram Pressure ◽  
Cold Gas

AbstractWe study the effect of ram pressure stripping (RPS) on the colours, cold gas content and star formation of galaxies in clusters, using a combination of N-Body/SPH simulations of galaxy clusters and a semi-analytic model of galaxy formation that includes the effect of RPS.

scholarly journals A New Catalog of Isolated Galaxies

2009 ◽  
Vol 5 (S267) ◽  
pp. 464-464
Author(s):  
J. A. Vázquez-Mata ◽  
H. M. Hernández-Toledo ◽  
Changbom Park ◽  
Yun-Young Choi
Keyword(s):  
Galaxy Formation ◽  
Environmental Effects ◽  
Comparative Studies ◽  
Sloan Digital Sky Survey ◽  
Selection Algorithm ◽  
Isolated Galaxies ◽  
Galaxy Formation And Evolution ◽  
Sky Survey ◽  
Data Release ◽  
Formation And Evolution

We present a new catalog of isolated galaxies (coined as UNAM–KIAS) obtained through an automated systematic search. The 1520 isolated galaxies were found in ~ 1.4 steradians of the sky in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5) photometry. The selection algorithm was implemented from a variation of the criteria developed by Karachentseva (1973), with full redshift information. This new catalog is aimed to carry out comparative studies of environmental effects and constraining the currently competing scenarios of galaxy formation and evolution.

scholarly journals ESTIMATING THE PROPAGATION OF A UNIFORMLY ACCELERATED JET

2021 ◽  
Vol 57 (2) ◽  
pp. 297-309
Author(s):  
J. I. Castorena ◽  
A. C. Raga ◽  
A. Esquivel ◽  
A. Rodríguez-González ◽  
L. Hernández-Martínez ◽  
...  
Keyword(s):  
Loss Rate ◽  
Mass Loss Rate ◽  
Center Of Mass ◽  
Analytic Solutions ◽  
Pressure Balance ◽  
Working Surface ◽  
Ram Pressure ◽  
Balance Solution ◽  
Analytic Models ◽  
Good Agreement

We study the problem of a Herbig-Haro jet with a uniformly accelerating ejection velocity, travelling into a uniform environment. For the ejection density we consider two cases: a time-independent density, and a time-independent mass loss rate. For these two cases, we obtain analytic solutions for the motion of the jet head using a ram-pressure balance and a center of mass equation of motion. We also compute axisymmetric numerical simulations of the same flow, and compare the time-dependent positions of the leading working surface shocks with the predictions of the two analytic models. We find that if the jet is over-dense and over-pressured (with respect to the environment) during its evolution, a good agreement is obtained with the analytic models, with the flow initially following the center of mass analytic solution, and (for the constant ejection density case) at later times approaching the ram-pressure balance solution.

scholarly journals Baryonic Dark Halos: a model with MACHOS and cold gas globules

1996 ◽  
Vol 171 ◽  
pp. 167-170
Author(s):  
Ortwin Gerhard ◽  
Joseph Silk
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Active Role ◽  
Galaxy Formation And Evolution ◽  
Substellar Objects ◽  
Formation And Evolution ◽  
Cold Gas

The dark matter in the halos of galaxies may well be baryonic, and much of the mass within them could be in the form of clusters of substellar objects within which are embedded cold gas globules. Such halos might play an active role in galaxy formation and evolution.

scholarly journals Environmental Mechanisms Shaping the Nature of Dwarf Spheroidal Galaxies: The View of Computer Simulations

2010 ◽  
Vol 2010 ◽  
pp. 1-21 ◽  
Author(s):  
Lucio Mayer
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Dwarf Galaxy ◽  
Feedback Mechanism ◽  
Gas Stripping ◽  
Morphological Transformation ◽  
Dwarf Spheroidal Galaxies ◽  
Tidal Forces ◽  
Ram Pressure ◽  
Low Metallicity

We review numerical works carried out over the last decade on the role of environmental mechanisms in shaping nature of the faintest galaxies known, dwarf spheroidals (dSphs). The combination of tidally induced morphological transformation, termed tidal stirring, with mass loss due to tidal and ram-pressure stripping aided by heating due to the cosmic ionizing background can turn late-type dwarfs resembling present-day dIrrs into classic dSphs. The time of infall into the primary halo is shown to be a key parameter. Dwarfs accreting at when the cosmic ultraviolet ionizing flux was much higher than today, and was thus able to keep the gas in the dwarfs warm and diffuse, were rapidly stripped of their baryons via ram pressure and tidal forces, producing very dark-matter-dominated objects with truncated star-formation histories, such as the Draco dSph. The low star-formation efficiency expected in such low-metallicity objects prior to their infall was crucial for keeping their disks gas dominated until stripping took over.Therefore gas stripping along with inefficient star-formation provides a new feedback mechanism, alternative to photoevaporation or supernovae feedback, playing a crucial role in dwarf galaxy formation and evolution. We also discuss how the ultra-faint dSphs belong to a different population of lower-mass dwarf satellites that were mostly shaped by reionization rather than by environmental mechanisms (“reionization fossils”). Finally, we scrutinize the various caveats in the current understanding of environmental effects as well as other recent ideas on the origin of Local Group dSphs.

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