Query : 2015A&A...575A..32C

2015A&A...575A..32C - Astronomy and Astrophysics, volume 575A, 32-32 (2015/3-1)

Galaxy stellar mass assembly: the difficulty matching observations and semi-analytical predictions.


Abstract (from CDS):

Semi-analytical models (SAMs) are currently the best way to understand the formation of galaxies within the cosmic dark-matter structures. They are able to give a statistical view of the variety of the evolutionary histories of galaxies in terms of star formation and stellar mass assembly. While they reproduce the local stellar mass functions, correlation functions, and luminosity functions fairly well, they fail to match observations at high redshift (z≥3) in most cases, particularly in the low-mass range. The inconsistency between models and CDM observations indicates that the history of gas accretion in galaxies, within their host dark-matter halo, and the transformation of gas into stars, are not followed well. We briefly present a new version of the GalICS semi-analytical model. With this new model, we explore the impact of classical mechanisms, such as supernova feedback or photoionization, on the evolution of the stellar mass assembly and the star formation rate. Even with strong efficiency, these two processes cannot explain the observed stellar mass function and star formation rate distribution or the stellar mass versus dark matter halo mass relation. We thus introduce an ad hoc modification of the standard paradigm, based on the presence of a no-star-forming gas component, and a concentration of the star-forming gas in galaxy discs. The main idea behind the existence of the no-star-forming gas reservoir is that only a fraction of the total gas mass in a galaxy is available to form stars. The reservoir generates a delay between the accretion of the gas and the star formation process. This new model is in much better agreement with the observations of the stellar mass function in the low-mass range than the previous models and agrees quite well with a large set of observations, including the redshift evolution of the specific star formation rate. However, it predicts a large amount of no-star-forming baryonic gas, potentially larger than observed, even if its nature has still to be examined in the context of the missing baryon problem. Outputs from all models are available at the CDS.

Abstract Copyright:

Journal keyword(s): galaxies: formation - galaxies: evolution - galaxies: star formation - galaxies: halos

VizieR on-line data: <CDS Catalogue: VI/143>

Simbad objects: 1

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Number of rows : 1
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 NAME Local Group GrG ~ ~           ~ 8378 0

Query : 2015A&A...575A..32C

Basic data :
NAME Local Group -- Group of Galaxies
Origin of the objects types :

(Ref) Object type as listed in the reference "Ref"
(acronym) Object type linked to the acronym according to the original reference
() Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases

Other object types:
GrG ([FWB89])
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
ICRS coord. (ep=J2000) :
No Coord.

Hierarchy : number of linked objects
whatever the membership probability is (see description here ) :

: 1
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%This number is the number of distinct objets linked, by using this button, you will obtain all links (may be more than one) from that object to his children

: 103
: 10 Display criteria :

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Identifiers (3) :
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NAME LG NAME Local Group [FWB89] GrG 282

References (8378 between 1850 and 2024) (Total 8378)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
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