scholarly journals The 1.4-GHz cosmic star formation history at z < 1.3

2019 ◽  
Vol 36 ◽  
Author(s):  
James E. Upjohn ◽  
Michael J. I. Brown ◽  
Andrew M. Hopkins ◽  
Nicolas J. Bonne
Keyword(s):  
Star Formation ◽  
Luminosity Function ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Radio Continuum ◽  
Star Formation History ◽  
Star Forming ◽  
Formation History ◽  
Radio Measurements ◽  
Radio Luminosity Function

AbstractWe measure the cosmic star formation history out to z = 1.3 using a sample of 918 radio-selected star-forming galaxies within the 2-deg2 COSMOS field. To increase our sample size, we combine 1.4-GHz flux densities from the VLA-COSMOS catalogue with flux densities measured from the VLA-COSMOS radio continuum image at the positions of I &lt; 26.5 galaxies, enabling us to detect 1.4-GHz sources as faint as 40 μJy. We find that radio measurements of the cosmic star formation history are highly dependent on sample completeness and models used to extrapolate the faint end of the radio luminosity function. For our preferred model of the luminosity function, we find the star formation rate density increases from 0.017 M⊙ yr−1 Mpc−3 at z ∼ 0.225 to 0.092 M⊙ yr−1 Mpc−3 at z ∼ 1.1, which agrees to within 40% of recent UV, IR and 3-GHz measurements of the cosmic star formation history.

scholarly journals Galaxies in the first billion years: implications for re-ionization and the star formation history at z>6

2006 ◽  
Vol 2 (14) ◽  
pp. 248-248
Author(s):  
Andrew J. Bunker ◽  
Elizabeth R. Stanway ◽  
Laurence P. Eyles ◽  
Richard S. Ellis ◽  
Richard G. McMahon ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Stellar Populations ◽  
Star Formation History ◽  
Star Forming ◽  
Formation History ◽  
Stellar Masses ◽  
The Universe ◽  
Selection Of

AbstractWe discuss the selection of star-forming galaxies at z≃6 through the Lyman-break technique. Spitzer imaging implies many of these contain older stellar populations (>200Myr) which produce detectable Balmer breaks. The ages and stellar masses (∼1010M⊙) imply that the star formation rate density at earlier epochs may have been significantly higher than at z≃6, and might have played a key role in re-ionizing the universe.

scholarly journals Does the evolution of the radio luminosity function of star-forming galaxies match that of the star formation rate function?

2017 ◽  
Vol 469 (2) ◽  
pp. 1912-1923 ◽  
Author(s):  
Matteo Bonato ◽  
Mattia Negrello ◽  
Claudia Mancuso ◽  
Gianfranco De Zotti ◽  
Paolo Ciliegi ◽  
...  
Keyword(s):  
Star Formation ◽  
Luminosity Function ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Rate Function ◽  
Radio Luminosity ◽  
Star Forming ◽  
Radio Luminosity Function

scholarly journals Star Formation Histories of Spiral Galaxies from a Multi-Wavelength Study

1996 ◽  
Vol 171 ◽  
pp. 471-471
Author(s):  
C. Xu
Keyword(s):  
Star Formation ◽  
Spiral Galaxies ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Radio Continuum ◽  
Star Formation History ◽  
The Past ◽  
Formation History ◽  
Star Formation Histories

We study the star formation histories of a sample of 113 nearby spiral galaxies using their radio continuum (20cm), FIR (40-120μm), H (1.65μm) and B (4400Å) luminosities. The first two are used as indicators of star formation rate over the past ∼ 108 years, as suggested by the tight and nearly universal FIR/radio correlation (Xu et al. 1994). Compared to other indicators of recent star formation rate such as Hα and UV, FIR and radio continuum have the advantage of being insensitive to extinction. The B luminosity is taken as star formation indicator for the time scale of 3 109 years, and the H luminosity for the time scale of 1010 years. We find: 1.The long-term star-formation history (from a few billion years to the entire Hubble time), as indicated by the B-to-H luminosity ratio, depends strongly on the Hubble type.2.The recent star-formation history in the last a few billion years, as indicated by the radio-to-B luminosity ratio and the FIR-to-B luminosity ratio, does not depend on the Hubble type.3.Galaxies of a given Hubble type have similar long-term star-formation histories. On the other hand, their recent star-formation histories in the last a few billion years can be much different: the ratio between the star-formation rate averaged over the past 108 years to that over the past 3 109 years can be different by two orders of magnitude, as indicated by the scattering of the radio-to-B luminosity ratio and that of the FIR-to-B luminosity ratio. This is not likely to be due to the extinction on the B luminosity, because the scattering of the B-to-H luminosity ratio for a given type is much smaller.

scholarly journals White dwarfs as advanced physics laboratories. The axion case

2019 ◽  
Vol 15 (S357) ◽  
pp. 138-153
Author(s):  
Jordi Isern
Keyword(s):  
Star Formation ◽  
Physical Properties ◽  
White Dwarfs ◽  
Luminosity Function ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Star Formation History ◽  
Formation History ◽  
The Galaxy ◽  
Physics Laboratories

AbstractThe shape of the luminosity function of white dwarfs (WDLF) is sensitive to the characteristic cooling time and, therefore, it can be used to test the existence of additional sources or sinks of energy such as those predicted by alternative physical theories. However, because of the degeneracy between the physical properties of white dwarfs and the properties of the Galaxy, the star formation history (SFH) and the IMF, it is almost always possible to explain any anomaly as an artifact introduced by the star formation rate. To circumvent this problem there are at least two possibilities, the analysis of the WDLF in populations with different stories, like disc and halo, and the search of effects not correlated with the SFH. These procedures are illustrated with the case of axions.

scholarly journals Quenching by gas compression and consumption

2019 ◽  
Vol 624 ◽  
pp. A81 ◽  
Author(s):  
Allison W. S. Man ◽  
Matthew D. Lehnert ◽  
Joël D. R. Vernet ◽  
Carlos De Breuck ◽  
Theresa Falkendal
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Relative Strength ◽  
Star Formation History ◽  
Molecular Gas ◽  
Host Galaxies ◽  
Massive Galaxies ◽  
Star Forming ◽  
Gas Compression ◽  
Formation History

The objective of this work is to study how active galactic nuclei (AGN) influence star formation in host galaxies. We present a detailed investigation of the star-formation history and conditions of a z = 2.57 massive radio galaxy based on VLT/X-shooter and ALMA observations. The deep rest-frame ultraviolet spectrum contains photospheric absorption lines and wind features indicating the presence of OB-type stars. The most significantly detected photospheric features are used to characterize the recent star formation: neither instantaneous nor continuous star-formation history is consistent with the relative strength of the Si IIλ1485 and S Vλ1502 absorption. Rather, at least two bursts of star formation took place in the recent past, at 6+1-2 Myr and ≳20 Myr ago, respectively. We deduce a molecular H2 gas mass of (3.9 ± 1.0) × 1010 M⊙ based on ALMA observations of the [C I] 3P2−3P1 emission. The molecular gas mass is only 13% of its stellar mass. Combined with its high star-formation rate of (1020-170+190 M⊙ yr-1, this implies a high star-formation efficiency of (26 ± 8) Gyr−1 and a short depletion time of (38 ± 12) Myr. We attribute the efficient star formation to compressive gas motions in order to explain the modest velocity dispersions (⩽55 km s−1) of the photospheric lines and of the star-forming gas traced by [C I]. Because of the likely very young age of the radio source, our findings suggest that vigorous star formation consumes much of the gas and works in concert with the AGN to remove any residual molecular gas, and eventually quenching star formation in massive galaxies.

scholarly journals Testing star formation rate indicators using galaxy merger simulations and radiative transfer

2009 ◽  
Vol 5 (S262) ◽  
pp. 257-260
Author(s):  
Christopher C. Hayward ◽  
Patrik Jonsson ◽  
Kai Noeske ◽  
Stijn Wuyts ◽  
T. J. Cox ◽  
...  
Keyword(s):  
Star Formation ◽  
Radiative Transfer ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Star Formation History ◽  
Spectral Energy ◽  
Merging Galaxies ◽  
Formation History ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

AbstractWe discuss our ongoing project analyzing N-body/smoothed-particle hydrodynamics simulations of isolated and merging galaxies, performed using GADGET-2 (Springel 2005), with the 3-D adaptive grid, polychromatic Monte Carlo radiative transfer code SUNRISE (Jonsson 2006). We apply commonly used UV, optical, and IR star formation rate (SFR) indicators to the integrated spectral energy distributions (SEDs) of the simulated galaxies in order to determine how well the SFR indicators recover the instantaneous SFR in the simulations. The models underlying each SFR indicator must necessarily make assumptions about physical properties of the galaxies, e.g., the star formation history (SFH), whereas all such properties are known in the simulations. This enables us to test and compare SFR indicators in a way that is complementary to observational studies. We present one preliminary result of interest: even after correcting the Hα luminosity for dust using the Calzetti et al. (2000) attenuation law the SFR is significantly underestimated for simulated galaxies with SFR ≳ 10 M⊙ yr−1.

scholarly journals Binary stars on the galaxy SFH

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
F. Zhang ◽  
L. Li ◽  
Z. Han
Keyword(s):  
Star Formation ◽  
Binary Stars ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Star Formation History ◽  
Population Synthesis ◽  
Feedback Process ◽  
Formation History ◽  
The Galaxy ◽  
Degeneracy Problem

AbstractUsing the Yunnan-II evolutionary population synthesis models comprising binary stars, we find that the inclusion of binary stars can raise the derived stellar metallicity Z* and/or age t (degeneracy problem), raise the stellar mass M*, lower the gaseous metallicity Zgas and star formation rate (SFR) of galaxies. This means that a few stars form recently in galaxies, while more stars form during the entire evolution process when considering binary stars. If the degeneracy between t and Z* can be broken, its effect on the feedback process and star formation history can be determined.

scholarly journals Evolution of the Luminosity Function, Star Formation Rate, Morphology, and Size of Star‐forming Galaxies Selected at Rest‐Frame 1500 and 2800 A

2007 ◽  
Vol 654 (1) ◽  
pp. 172-185 ◽  
Author(s):  
Tomas Dahlen ◽  
Bahram Mobasher ◽  
Mark Dickinson ◽  
Henry C. Ferguson ◽  
Mauro Giavalisco ◽  
...  
Keyword(s):  
Star Formation ◽  
Luminosity Function ◽  
Rest Frame ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Star Forming

scholarly journals Cosmic Star Formation from the Milky Way and its Satellites

1999 ◽  
Vol 190 ◽  
pp. 8-14
Author(s):  
F.D.A. Hartwick
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Star Formation History ◽  
Evolutionary Models ◽  
Disk Mass ◽  
Formation History ◽  
History Of ◽  
The Universe

We use observations and evolutionary models of local objects to interpret a recent determination of the star-formation history of the universe. By fitting the global star-formation rate, the model predicts the ratio of spheroid to disk mass of ~1, an intergalactic medium (IGM) whose mass is ~2.3 times the mass in stars, and whose metallicity is ~0.1 Z⊙.

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