scholarly journals Star formation in bulges from GALEX

2007 ◽  
Vol 3 (S245) ◽  
pp. 385-390
Author(s):  
Sukyoung K. Yi
Keyword(s):  
Star Formation ◽  
Young Stars ◽  
Star Formation History ◽  
Early Type ◽  
Limited Sample ◽  
Cluster Galaxies ◽  
Brightest Cluster Galaxies ◽  
Formation History ◽  
Formation And Evolution ◽  
Bulge Formation

AbstractEarly-type galaxies, considered as large bulges, have been found to have had a much-more-than-boring star formation history in recent years by the UV satellite GALEX. The most massive bulges, brightest cluster galaxies, appear to be relatively free of young stars. But smaller bulges, normal ellipticals and lenticulars, often show unambiguous sign of recent star formation in their UV flux. The fraction of such UV-bright bulges in the volume-limited sample climbs up to the staggering 30%. The bulges of spirals follow similar trends but a larger fraction showing signs of current and recent star formation. The implication on the bulge formation and evolution is discussed.

scholarly journals The hierarchical evolution of Brightest Cluster Galaxies: red galaxies in a young universe

2012 ◽  
Vol 8 (S295) ◽  
pp. 200-203
Author(s):  
Chiara Tonini
Keyword(s):  
Star Formation ◽  
Stellar Populations ◽  
Star Formation History ◽  
Analytic Model ◽  
Cluster Galaxies ◽  
Star Formation Activity ◽  
Brightest Cluster Galaxies ◽  
Formation History ◽  
Red Galaxies ◽  
Analytic Models

AbstractWe investigate the evolution of Brightest Cluster Galaxies (BCGs) from redshift z ~ 1.6 to z = 0. We upgrade the hierarchical semi-analytic model of Croton et al. (2006) with a new spectro-photometric model that produces realistic galaxy spectra, making use of the Maraston (2005) stellar populations and a new recipe for the dust extinction. We compare the model predictions of the K-band luminosity evolution and the J-K, V-I and I-K colour evolution with a series of datasets, including Collins et al. (Nature, 2009) who argued that semi-analytic models based on the Millennium simulation cannot reproduce the red colours and high luminosity of BCGs at z > 1. We show instead that the model is well in range of the observed luminosity and correctly reproduces the colour evolution of BCGs in the whole redshift range up to z ~ 1.6. We argue that the success of the semi-analytic model is in large part due to the implementation of a more sophisticated spectro-photometric model. An analysis of the model BCGs shows an increase in mass by a factor 2-3 since z ~ 1, and star formation activity down to low redshifts. While the consensus regarding BCGs is that they are passively evolving, we argue that this conclusion is affected by the degeneracy between star formation history and stellar population models used in SED-fitting, and by the inefficacy of toy-models of passive evolution to capture the complexity of real galaxies, especially those with rich merger histories like BCGs. Following this argument, we also show that in the semi-analytic model, the BCGs show a realistic mix of stellar populations, and that these stellar populations are mostly old. In addition, the age-redshift relation of the model BCGs follows that of the Universe, meaning that given their merger history and star formation history, the ageing of BCGs is always dominated by the ageing of their stellar populations. In a ΛCDM Universe, we define such evolution as ‘passive in the hierarchical sense’.

scholarly journals Did brightest cluster galaxies experience more than one star formation epoch?

2012 ◽  
Vol 8 (S295) ◽  
pp. 320-320
Author(s):  
D. N. Viljoen ◽  
S. I. Loubser
Keyword(s):  
Star Formation ◽  
Population Model ◽  
Stellar Population ◽  
Star Formation History ◽  
Full Spectrum ◽  
Cluster Galaxies ◽  
Brightest Cluster Galaxies ◽  
Formation History ◽  
Spectrum Fitting ◽  
Fitting Ability

AbstractWe use the full spectrum fitting ability of ULySS, with the Pegase.HR stellar population model to fit the observed spectra of 40 brightest cluster galaxies in order to determine whether a single or a composite stellar population provided the most probable representation of the star formation history (SFH). We find that some galaxies in the sample have more complex SFHs.

scholarly journals Young stars in nearby early-type galaxies: The GALEX-SAURON perspective

2012 ◽  
Vol 10 (H16) ◽  
pp. 125-125
Author(s):  
Hyunjin Jeong ◽  
Sukyoung K. Yi ◽  
Martin Bureau ◽  
Roger L. Davies
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Strong Evidence ◽  
Young Stars ◽  
Star Formation History ◽  
Early Type ◽  
Fundamental Plane ◽  
Low Level ◽  
Formation History ◽  
The Galaxy

Recent studies from the Galaxy Evolution Explore (GALEX) ultraviolet (UV) data reveal that the recent star formation is more common in early-type galaxies (ETGs) that we used to believe (Jeong et al.2007). Here we used the unique GALEX UV data on existing SAURON IFU-studied galaxies and combined these two datasets (UV and IFU) to find where photometric anomalies occur. One of the highlights of our study is the work on the Fundamental Plane (FP). The tilt and scatter found in optical FPs have been an issue. From our sample of 34 ETGs, we found that most of the tilt and scatter are caused by the minority ETGs which have been forming stars recently at very low level (see figure 1). Using our UV FPs, we found a strong evidence for star formation history being the main source of the mystery (Jeong et al.2009).

scholarly journals The Structure and Star Formation History of Early‐Type Galaxies in the Ultra Deep Field/GRAPES Survey

2006 ◽  
Vol 636 (1) ◽  
pp. 115-133 ◽  
Author(s):  
A. Pasquali ◽  
I. Ferreras ◽  
N. Panagia ◽  
E. Daddi ◽  
S. Malhotra ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation History ◽  
Early Type ◽  
Formation History ◽  
History Of

scholarly journals A Comparison of Chemical Evolution between the Milky Way and M31 Galaxy

2006 ◽  
Vol 2 (S235) ◽  
pp. 313-313
Author(s):  
J. Yin ◽  
J.L. Hou ◽  
R.X. Chang ◽  
S. Boissier ◽  
N. Prantzos
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Milky Way ◽  
Local Group ◽  
Spiral Galaxies ◽  
Star Formation History ◽  
Milky Way Galaxy ◽  
Andromeda Galaxy ◽  
Formation History ◽  
Formation And Evolution

Andromeda galaxy (M31,NGC224) is the biggest spiral in the Local Group. By studying the star formation history(SFH) and chemical evolution of M31, and comparing with the Milky Way Galaxy, we are able to understand more about the formation and evolution of spiral galaxies.

scholarly journals Molecular gas in distant brightest cluster galaxies

2020 ◽  
Vol 635 ◽  
pp. A32 ◽  
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.

VIPERS view of the star formation history of early-type galaxies

2015 ◽  
Author(s):  
M. Siudek ◽  
K. Malek ◽  
B. Garilli ◽  
M. Scodeggio ◽  
A. Fritz ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation History ◽  
Early Type ◽  
Formation History ◽  
History Of

Age, Metallicity, and Star Formation History of Cluster Galaxies atz ∼ 0.3

2003 ◽  
Vol 589 (1) ◽  
pp. 147-156 ◽  
Author(s):  
P. Merluzzi ◽  
F. La Barbera ◽  
M. Massarotti ◽  
G. Busarello ◽  
M. Capaccioli
Keyword(s):  
Star Formation ◽  
Star Formation History ◽  
Cluster Galaxies ◽  
Formation History ◽  
History Of
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