Star-formation rates and forbidden O II emission in blue galaxies

1989 ◽  
Vol 97 ◽  
pp. 700 ◽  
Author(s):  
J. S. Gallagher ◽  
D. A. Hunter ◽  
H. Bushouse
Keyword(s):  
Star Formation ◽  
Blue Galaxies

scholarly journals Determination of Young Population Ages in Cluster Galaxies

1995 ◽  
Vol 164 ◽  
pp. 460-460
Author(s):  
B.M. Poggianti ◽  
G. Barbaro
Keyword(s):  
Star Formation ◽  
Young Stars ◽  
Young Population ◽  
Cluster Galaxies ◽  
Blue Galaxies

The “Butcher–Oemler” effect was originally defined as the excess of blue galaxies observed in distant rich clusters when compared to local counterparts. Subsequent observations revealed that a larger fraction of objects in clusters between 0.1 < z < 1 show signs in their spectra of the presence of young stars, i.e. of a recent (during the last 2 Gyrs) or current burst of star formation.

scholarly journals The Evolution of Luminous Compact Blue Galaxies: Disks or Spheroids?

2010 ◽  
Vol 6 (S277) ◽  
pp. 291-295
Author(s):  
D. J. Pisano ◽  
K. Rabidoux ◽  
C. A. Garland ◽  
R. Guzmán ◽  
F. J. Castander ◽  
...  
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
High Surface ◽  
Blue Color ◽  
Dynamical Mass ◽  
Star Forming ◽  
Blue Galaxies ◽  
Multi Wavelength ◽  
Fisher Relation ◽  
Combined Data

AbstractLuminous compact blue galaxies (LCBGs) are a diverse class of galaxies characterized by high luminosity, blue color, and high surface brightness that sit at the critical juncture of galaxies evolving from the blue to the red sequence. As part of our multi-wavelength survey of local LCBGs, we have been studying the HI content of these galaxies using both single-dish telescopes and interferometers. Our goals are to determine if single-dish HI observations represent a true measure of the dynamical mass of LCBGs and to look for signatures of recent interactions that may be triggering star formation in LCBGs. Our data show that while some LCBGs are undergoing interactions, many appear isolated. While all LCBGs contain HI and show signatures of rotation, the population does not lie on the Tully-Fisher relation nor can it evolve onto it. Furthermore, the HI maps of many LCBGs show signatures of dynamically hot components, suggesting that we are seeing the formation of a thick disk or spheroid in at least some LCBGs. There is good agreement between the HI and Hα kinematics for LCBGs, and both are similar in appearance to the Hα kinematics of high redshift star-forming galaxies. Our combined data suggest that star formation in LCBGs is primarily quenched by virial heating, consistent with model predictions.

Star formation in blue galaxies

1977 ◽  
Vol 217 ◽  
pp. 928 ◽  
Author(s):  
J. P. Huchra
Keyword(s):  
Star Formation ◽  
Blue Galaxies

Star formation in blue galaxies. I - Ultraviolet, optical, and infrared observations of NGC 4214 and NGC 4670

1983 ◽  
Vol 274 ◽  
pp. 125 ◽  
Author(s):  
J. P. Huchra ◽  
M. J. Geller ◽  
J. Gallagher ◽  
D. Hunter ◽  
L. Hartmann ◽  
...  
Keyword(s):  
Star Formation ◽  
Infrared Observations ◽  
Blue Galaxies

scholarly journals The Morphological Evolution of Field Galaxies

1995 ◽  
Vol 164 ◽  
pp. 291-300
Author(s):  
Richard S. Ellis
Keyword(s):  
Star Formation ◽  
Luminosity Function ◽  
Morphological Evolution ◽  
Morphological Type ◽  
Physical Explanation ◽  
Normal Field ◽  
Hubble Sequence ◽  
Blue Galaxies ◽  
Intense Star Formation

I review two observational programs which, together, promise to unravel the detailed astrophysical evolution of normal field galaxies over the last 5-7 Gyr. Systematic ground-based spectroscopy of faint galaxies have revealed an increasing faint end slope for the luminosity function with redshift. The trend is strongest for galaxies undergoing intense star-formation. Deep images taken with the repaired HST can be used to count galaxies as a function of morphological type. Regular “Hubble sequence” galaxies follow the no-evolution prediction, but irregular/peculiar sources have a steeper count slope and provide the excess population. Although the overlap between the spectral and HST samples is currently small, plans to merge similar datasets should reveal the physical explanation for the demise of star formation in faint blue galaxies since z ≃0.5-l.

scholarly journals The VIMOS Public Extragalactic Redshift Survey (VIPERS)

2018 ◽  
Vol 620 ◽  
pp. A193 ◽  
Author(s):  
D. Vergani ◽  
B. Garilli ◽  
M. Polletta ◽  
P. Franzetti ◽  
M. Scodeggio ◽  
...  
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Starburst Galaxies ◽  
Host Galaxies ◽  
Star Formation Activity ◽  
Blue Galaxies ◽  
Redshift Survey ◽  
The Rich ◽  
Stellar Masses ◽  
Red Sequence

Aims. We analyse the properties of the host galaxies of a [NeV]-selected sample to investigate whether and how they are affected by the AGN. Methods. We have selected a sample of galaxies at 0.62 <  z <  1.2 from the VIMOS Public Extragalactic Redshift Survey (VIPERS) and divided it in blue cloud galaxies, red passive galaxies and green valley galaxies using the NUVrK diagram. Within each category, galaxies with AGN activity were identified based on the detection of the high-ionisation [NeV]λ3426 emission line. For each galaxy we derived several properties (stellar age and mass, the (r−K) colour, the [OII] luminosity) and compared them between active and inactive galaxies matched in stellar mass and redshift. Results. We find statistically significant differences in the properties between active and inactive galaxies. These differences imply that the AGN is more often found in galaxies with younger stellar populations and more recent star-forming activity than their parent samples. Interestingly, the AGN identified through the [NeV]λ3426 emission line is not commonly found by traditional AGN-selection techniques based on shallow X-ray data, mid-IR colours, and classical line diagnostic diagrams, and might thus reveal a specific evolutionary phase. The spectral analysis reveals a sub-set of AGN within the blue cloud that has spectral signatures implying a sudden suppression of star formation activity similar to post-starburst galaxies. Conclusion. Using the rich dataset of the large VIPERS sample we identify a novel class of active post-starburst galaxies that would be missed by traditional selection techniques. These galaxies belong to the blue cloud, but their star-formation activity has been recently suppressed, possibly by the AGN identified through the presence of the [NeV]λ3426 emission line in their spectra. Our results support the idea that AGN feedback may be responsible for halting star-formation in active blue galaxies and for their transition into the red sequence, at least in the 0.6–1.2 redshift range and for stellar masses greater than 5 × 1010 ℳ⊙. Our results are based on a complete spectroscopic sample and limited by the [NeV] observability, and the AGN can be variable and with a relatively short duty cycle. Considering this, AGN feedback that makes blue galaxies quickly transition to the red sequence may be even more common than previously believed.

scholarly journals Bursting and quenching in satellite galaxies

2019 ◽  
Vol 490 (4) ◽  
pp. 5375-5389 ◽  
Author(s):  
I Koutsouridou ◽  
A Cattaneo
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Mass Function ◽  
Chemical Enrichment ◽  
Galactic Winds ◽  
Theoretical Predictions ◽  
Blue Galaxies ◽  
Satellite Galaxies ◽  
The Difference ◽  
Red Galaxies

ABSTRACT The difference in stellar metallicity between red and blue galaxies with the same mass constrains the time-scale over which red galaxies ceased to form stars. Here we investigate this constraint with the galics 2.0 semi-analytic model of galaxy formation. The advantage of this approach is that the time of pericentric passages for satellite galaxies and the mass-loading factor for galactic winds are not free parameters of the chemical evolution model. The former is determined by the N-body simulation used to construct the merger trees, the latter by the requirement that galics 2.0 should reproduce the stellar mass function of galaxies. When we compare our theoretical predictions with observations, we find that galics 2.0 can reproduce the observed metallicity difference only if quenching is preceded by a burst of star formation, which contributes to the chemical enrichment of the stellar population. Physically, this burst can be explained as tidally induced star formation or as an effect of ram pressure, which not only strips gas from galaxies but also compresses it, accelerating its conversion into stars.

scholarly journals Galaxy Environments in DEEP2: The Birth of the Red Sequence

2006 ◽  
Vol 2 (S235) ◽  
pp. 167-169
Author(s):  
Michael C. Cooper ◽  
Jeffrey A. Newman
Keyword(s):  
Star Formation ◽  
Evolutionary Trends ◽  
Early Type ◽  
Number Density ◽  
Late Type ◽  
Active Star ◽  
The Galaxy ◽  
Blue Galaxies ◽  
Galaxy Population ◽  
Red Sequence

The galaxy population at z ≲ 1 is effectively described as a combination of two distinct types: red, early-type galaxies lacking much star formation and blue, late-type galaxies with active star formation. For the red galaxy population, recent work by Bell et al. (2004) has shown that the number density of ~L* galaxies on the red sequence has risen by a factor of ~2 from z ~ 1 to z ~ 0. A variety of complementary observations suggests that the build-up of galaxies on the red sequence results from 2 distinct evolutionary trends: (1) the quenching of star formation in blue galaxies and their subsequent migration onto the red sequence and (2) the dissipationless or (“dry”) merging of red-sequence galaxies.

scholarly journals Spectroscopy and Photometry of Faint Galaxies: Hints at their Evolution

1980 ◽  
Vol 92 ◽  
pp. 39-48
Author(s):  
Hyron Spinrad
Keyword(s):  
Star Formation ◽  
Simple Model ◽  
Galactic Evolution ◽  
Optical Methods ◽  
Time Interval ◽  
Short Time Interval ◽  
Large Samples ◽  
Faint Galaxy ◽  
Blue Galaxies ◽  
Short Time

I discuss four optical methods to locate standard candles (giant E galaxies), which should eventually lead us to reasonably large samples at high z. Redshift criteria and determinations are briefly discussed. The observed faint galaxy colors fit well into a simple model of stellar (galactic) evolution for systems with star-formation confined to a short time interval. Finally a summary of the statistics of blue galaxies in Coma-like clusters (Butcher-Oemler effect) is presented and interpreted.

scholarly journals The XXL Survey

2019 ◽  
Vol 625 ◽  
pp. A112 ◽  
Author(s):  
V. Guglielmo ◽  
B. M. Poggianti ◽  
B. Vulcani ◽  
S. Maurogordato ◽  
J. Fritz ◽  
...  
Keyword(s):  
Star Formation ◽  
Stellar Population ◽  
Main Sequence ◽  
Formation Rate ◽  
Local Environment ◽  
Star Forming ◽  
Blue Galaxies ◽  
Galaxy Populations ◽  
Definition Of ◽  
Star Formation Histories

Exploiting a sample of galaxies drawn from the XXL-North multiwavelength survey, we present an analysis of the stellar population properties of galaxies at 0.1 ≤ z ≤ 0.5, by studying galaxy fractions and the star formation rate (SFR)–stellar mass (M⋆) relation. Furthermore, we exploit and compare two parametrisations of environment. When adopting a definition of “global” environment, we consider separately cluster virial (r ≤ 1r200) and outer (1r200 <  r ≤ 3r200) members and field galaxies. We also distinguish between galaxies that belong or do not belong to superclusters, but never find systematic differences between the two subgroups. When considering the “local” environment, we take into account the projected number density of galaxies in a fixed aperture of 1 Mpc in the sky. We find that regardless of the environmental definition adopted, the fraction of blue or star-forming galaxies is the highest in the field or least dense regions and the lowest in the virial regions of clusters or highest densities. Furthermore, the fraction of star-forming galaxies is higher than the fraction of blue galaxies, regardless of the environment. This result is particularly evident in the virial cluster regions, most likely reflecting the different star formation histories of galaxies in different environments. Also the overall SFR–M⋆ relation does not seem to depend on the parametrisation adopted. Nonetheless, the two definitions of environment lead to different results as far as the fraction of galaxies in transition between the star-forming main sequence and the quenched regime is concerned. In fact, using the local environment the fraction of galaxies below the main sequence is similar at low and high densities, whereas in clusters (and especially within the virial radii) a population with reduced SFR with respect to the field is observed. Our results show that the two parametrisations adopted to describe the environment have different physical meanings, i.e. are intrinsically related to different physical processes acting on galaxy populations and are able to probe different physical scales.

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