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 The global star formation law: from dense cores to extreme starbursts

2006 ◽  
Vol 2 (S237) ◽  
pp. 331-335
Author(s):  
Yu Gao
Keyword(s):  
Star Formation ◽  
Linear Correlation ◽  
Molecular Clouds ◽  
High Redshift ◽  
Gas Content ◽  
Molecular Gas ◽  
Giant Molecular Clouds ◽  
Active Star ◽  
Dense Cores ◽  
The Galaxy

AbstractActive star formation (SF) is tightly related to the dense molecular gas in the giant molecular clouds' dense cores. Our HCN (measure of the dense molecular gas) survey in 65 galaxies (including 10 ultraluminous galaxies) reveals a tight linear correlation between HCN and IR (SF rate) luminosities, whereas the correlation between IR and CO (measure of the total molecular gas) luminosities is nonlinear. This suggests that the global SF rate depends more intimately upon the amount of dense molecular gas than the total molecular gas content. This linear relationship extends to both the dense cores in the Galaxy and the hyperluminous extreme starbursts at high-redshift. Therefore, the global SF law in dense gas appears to be linear all the way from dense cores to extreme starbursts, spanning over nine orders of magnitude in IR luminosity.

scholarly journals The Galaxy Environment of Quasars in the z ⋍ 1.3 Clowes-Campusano Large Quasar Group

2005 ◽  
Vol 201 ◽  
pp. 465-466
Author(s):  
C. P. Haines ◽  
R. G. Clowes ◽  
L. E. Campusano
Keyword(s):  
Star Formation ◽  
The Galaxy ◽  
Galaxy Environment ◽  
Red Sequence

We report significant associated clustering in the field of a z = 1.226 quasar from the Clowes-Campusano LQG in the form of both a factor ˜ 11 overdensity of I - K > 3.75 galaxies, and red sequences of 15-18 galaxies at I - K ⋍ 4.3, V - K ⋍ 6.9 indicative of a population of massive ellipticals at the quasar redshift. The quasar is located between two groups of these galaxies, with further clustering extending over 2-3 Mpc. A band of V - I < 1 galaxies bisects the two groups of red sequence galaxies, and we suggest that the merging of these two groups has triggered both this band of star-formation and the quasar.

scholarly journals Redshift measurement through star formation

2019 ◽  
Vol 629 ◽  
pp. A7
Author(s):  
Mikkel O. Lindholmer ◽  
Kevin A. Pimbblet
Keyword(s):  
Star Formation ◽  
Galaxy Clusters ◽  
Main Sequence ◽  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
X Ray ◽  
Star Forming ◽  
Sky Survey ◽  
The Galaxy ◽  
Galaxy Population

In this work we use the property that, on average, star formation rate increases with redshift for objects with the same mass – the so called galaxy main sequence – to measure the redshift of galaxy clusters. We use the fact that the general galaxy population forms both a quenched and a star-forming sequence, and we locate these ridges in the SFR–M⋆ plane with galaxies taken from the Sloan Digital Sky Survey in discrete redshift bins. We fitted the evolution of the galaxy main sequence with redshift using a new method and then subsequently apply our method to a suite of X-ray selected galaxy clusters in an attempt to create a new distance measurement to clusters based on their galaxy main sequence. We demonstrate that although it is possible in several galaxy clusters to measure the main sequences, the derived distance and redshift from our galaxy main sequence fitting technique has an accuracy of σz = ±0.017 ⋅ (z + 1) and is only accurate up to z ≈ 0.2.

scholarly journals Supernova Rates

1996 ◽  
Vol 145 ◽  
pp. 1-9 ◽  
Author(s):  
Sidney Van Den Bergh
Keyword(s):  
Luminosity Function ◽  
Historical Data ◽  
Starburst Galaxies ◽  
Early Type ◽  
Late Type ◽  
Interstellar Absorption ◽  
Blue Galaxies ◽  
S0 Galaxies ◽  
Intermediate Redshifts ◽  
Parent Galaxy

Extragalactic supernova rates are reviewed. The main uncertainties in calculated rates are due to (1) the influence of the (still poorly known) luminosity function of supernova of a given type on “control times”, to (2) uncertain corrections for possible inclination - dependent bias in supernova discovery probabilities, and (3) interstellar absorption. The total supernova rate in late-type galaxies is found to be ∼ 2(H0/75)2 supernovae (SNe) per century per 1010LB(ʘ) This is consistent with the rate of 3 SNe per century that is derived from the historical data on Galactic supernovae. It is, however, a source of some concern that none of the three Galactic SNe expected to have occurred during the last century was actually observed!The expansion velocities of SNe Ia are found to correlate strongly with parent galaxy Hubble type. This relation is in the sense that low expansion velocities are only observed for those SNe Ia that occur in early-type galaxies. This suggests that V(exp) correlates with the ages of SNe Ia progenitors. It is speculated that the progenitors of a few SNe Ia with high V(exp) values in E and S0 galaxies were formed during recent starbursts.SNe Ia rates appear to be enhanced in post-starburst galaxies. It is suggested that supernova rates might be quite high in the recently discovered population of faint blue galaxies at intermediate redshifts.

scholarly journals Study of a Complete Sample of Hα Emission–Line Galaxies from the UCM Survey

1996 ◽  
Vol 171 ◽  
pp. 380-380 ◽  
Author(s):  
J. Gallego ◽  
J. Zamorano ◽  
M. Rego ◽  
A.G. Vitores ◽  
O. Alonso
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Energy Output ◽  
University Of Michigan ◽  
Complete Sample ◽  
Star Forming ◽  
The Galaxy ◽  
Hα Emission ◽  
Emission Line Galaxies ◽  
Galaxy Population

The Universidad Complutense de Madrid survey is a long-term project with the aim of finding and analyzing star forming galaxies using the Hα line as the tracer for star formation processes. In order to obtain a representative and complete sample of the population detected, spectroscopic observations were carried out for the full sample of Hα emission-line galaxy (ELG) candidates of the UCM lists 1 and 2. The ELGs types most commonly found (47%) are intermediate to low-luminosity objects with a very intense star-formation region which dominates the optical energy output of the galaxy. This kind of ELGs is similar to the galaxy population detected in the blue objective-prism surveys. And what is more important, a second population (43%) of star-forming galaxies with low ionization or high extinction properties has been found. This ELGs group is detected neither in the blue (University of Michigan survey, Case survey) nor in other surveys (Kiso, IRAS, Markarian) using other selection techniques.

scholarly journals A Simulation of Galaxy Formation by Radiation-SPH

2003 ◽  
Vol 208 ◽  
pp. 323-330
Author(s):  
Hajime Susa ◽  
Masayuki Umemura
Keyword(s):  
Star Formation ◽  
Radiation Field ◽  
Galaxy Formation ◽  
Background Radiation ◽  
Early Type ◽  
Late Type ◽  
Lower Redshift

We investigate galaxy formation with Radiation-SPH simulations in order to find the effects of ultraviolet background radiation field on the star formation in the forming galaxies. We find the ultraviolet background radiation field can delay the star formation in protogalactic clouds, especially at low redshift (z < 2). This result suggests that galaxies formed at lower redshift tend to be late type galaxies, and early type galaxies tend to be formed at higher redshift.

scholarly journals Star Formation Histories of Dwarf Galaxies from the Colour-Magnitude Diagrams of Their Resolved Stellar Populations

2010 ◽  
Vol 2010 ◽  
pp. 1-25 ◽  
Author(s):  
Michele Cignoni ◽  
Monica Tosi
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Dwarf Galaxies ◽  
Early Type ◽  
Significant Difference ◽  
Magnitude Diagram ◽  
The Galaxy ◽  
Show Evidence ◽  
History Of ◽  
Star Formation Histories

In this tutorial paper we summarize how the star formation (SF) history of a galactic region can be derived from the colour-magnitude diagram (CMD) of its resolved stars. The procedures to build synthetic CMDs and to exploit them to derive the SF histories (SFHs) are described, as well as the corresponding uncertainties. The SFHs of resolved dwarf galaxies of all morphological types, obtained from the application of the synthetic CMD method, are reviewed and discussed. To summarize: (1) only early-type galaxies show evidence of long interruptions in the SF activity; late-type dwarfs present rather continuous, orgasping, SF regimes; (2) a few early-type dwarfs have experienced only one episode of SF activity concentrated at the earliest epochs, whilst many others show extended or recurrent SF activity; (3) no galaxy experiencing now its first SF episode has been found yet; (4) no frequent evidence of strong SF bursts is found; (5) there is no significant difference in the SFH of dwarf irregulars and blue compact dwarfs, except for the current SF rates. Implications of these results on the galaxy formation scenarios are briefly discussed.

scholarly journals The SAURON project - XV. Modes of star formation in early-type galaxies and the evolution of the red sequence

2010 ◽  
Vol 402 (4) ◽  
pp. 2140-2186 ◽  
Author(s):  
Kristen L. Shapiro ◽  
Jesús Falcón-Barroso ◽  
Glenn van de Ven ◽  
P. Tim de Zeeuw ◽  
Marc Sarzi ◽  
...  
Keyword(s):  
Star Formation ◽  
Early Type ◽  
Red Sequence

scholarly journals Nature of bulges in the Hubble sequence

2007 ◽  
Vol 3 (S245) ◽  
pp. 309-310
Author(s):  
Eija Laurikainen ◽  
H. Salo ◽  
R. Buta ◽  
J. H. Knapen
Keyword(s):  
Star Formation ◽  
Strong Evidence ◽  
Disk Galaxies ◽  
Early Type ◽  
Late Type ◽  
Hubble Sequence

AbstractWe evaluate the nature of bulges in the Hubble sequence, based on an analysis of 216 disk galaxies of all morphological types (S0-Sd). For this purpose we collect our various analysis made separately for early and late-type galaxies, published in a series of papers. Using the criteria by Kormendy & Kennicutt we find strong evidence of pseudobulges in all Hubble types, including S0s. However, due to the relatively massive bulges in S0-S0/a galaxies it is not probable that the (pseudo)bulges in these galaxies were formed in a similar manner as in spirals. More likely, pseudobulges particularly in strongly barred early-type disk galaxies are suggested to be a combination of star formation and the nearly exponential central components of bars.

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