scholarly journals Evolution of the cold gas fraction and the star formation history: Prospects with current and future radio facilities

2018 ◽  
Vol 35 ◽  
Author(s):  
S. J. Curran
Keyword(s):  
Star Formation ◽  
Neutral Hydrogen ◽  
Star Formation History ◽  
Spin Temperature ◽  
Star Forming ◽  
Neutral Gas ◽  
Contemporary Sample ◽  
Formation History ◽  
Radio Band ◽  
Cold Gas

AbstractIt has recently been shown that the abundance of cold neutral gas may follow a similar evolution as the star formation history. This is physically motivated, since stars form out of this component of the neutral gas and if the case, would resolve the long-standing issue that there is a clear disparity between the total abundance of neutral gas and star-forming activity over the history of the Universe. Radio-band 21-cm absorption traces the cold gas and comparison with the Lyman-α absorption, which traces all of the gas, provides a measure of the cold gas fraction, or the spin temperature, Tspin. The recent study has shown that the spin temperature (degenerate with the ratio of the absorber/emitter extent) appears to be anti-correlated with the star formation density, ψ*, with 1/Tspin undergoing a similar steep evolution as ψ* over redshifts of 0 ≲ z ≲ 3, whereas the total neutral hydrogen exhibits little evolution. Above z ∼ 3, where ψ* shows a steep decline with redshift, there are insufficient 21-cm data to determine whether 1/Tspin continues to follow ψ*. Knowing this is paramount in ascertaining whether the cold neutral gas does trace the star formation over the Universe’s history. We explore the feasibility of resolving this with 21-cm observations of the largest contemporary sample of reliable damped Lyman-α absorption systems and conclude that, while today’s largest radio interferometers can reach the required sensitivity at z ≲ 3.5, the Square Kilometre Array is required to probe higher redshifts.

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 ACHANDRASTUDY OF THE ROSETTE STAR-FORMING COMPLEX. III. THE NGC 2237 CLUSTER AND THE REGION'S STAR FORMATION HISTORY

2010 ◽  
Vol 716 (1) ◽  
pp. 474-489 ◽  
Author(s):  
Junfeng Wang ◽  
Eric D. Feigelson ◽  
Leisa K. Townsley ◽  
Patrick S. Broos ◽  
Carlos G. Román-Zúñiga ◽  
...  
Keyword(s):  
Star Formation ◽  
Complex Iii ◽  
Star Formation History ◽  
Star Forming ◽  
Formation History

scholarly journals Star-Forming Galaxies at Cosmic Noon

2020 ◽  
Vol 58 (1) ◽  
pp. 661-725 ◽  
Author(s):  
Natascha M. Förster Schreiber ◽  
Stijn Wuyts
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Star Formation History ◽  
Massive Galaxies ◽  
Star Forming ◽  
Dense Cores ◽  
Gravitational Instabilities ◽  
James Webb Space Telescope ◽  
Formation History ◽  
Large Telescopes

Ever deeper and wider look-back surveys have led to a fairly robust outline of the cosmic star-formation history, which culminated around [Formula: see text]; this period is often nicknamed “cosmic noon.” Our knowledge about star-forming galaxies at these epochs has dramatically advanced from increasingly complete population censuses and detailed views of individual galaxies. We highlight some of the key observational insights that influenced our current understanding of galaxy evolution in the equilibrium growth picture: ▪  Scaling relations between galaxy properties are fairly well established among massive galaxies at least out to [Formula: see text], pointing to regulating mechanisms already acting on galaxy growth. ▪  Resolved views reveal that gravitational instabilities and efficient secular processes within the gas- and baryon-rich galaxies at [Formula: see text] play an important role in the early buildup of galactic structure. ▪  Ever more sensitive observations of kinematics at [Formula: see text] are probing the baryon and dark matter budget on galactic scales and the links between star-forming galaxies and their likely descendants. ▪  Toward higher masses, massive bulges, dense cores, and powerful AGNs and AGN-driven outflows are more prevalent and likely play a role in quenching star formation. We outline emerging questions and exciting prospects for the next decade with upcoming instrumentation, including the James Webb Space Telescope and the next generation of extremely large telescopes.

scholarly journals Recent Star Formation History of the Magellanic Clouds

1999 ◽  
Vol 190 ◽  
pp. 470-472
Author(s):  
Eva K. Grebel ◽  
Wolfgang Brandner
Keyword(s):  
Star Formation ◽  
Large Scale ◽  
New Age ◽  
Magellanic Clouds ◽  
Star Formation History ◽  
Star Forming ◽  
Formation History ◽  
History Of

A new age calibration of Cepheids and supergiants is used to study the large-scale recent star formation history of the LMC and the SMC. We find evidence for migration of star formation along the LMC bar as well as for the existence of long-lived (≈ 200 Myr) extended star-forming features.

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 The Cosmic Baryon and Metal Cycles

2020 ◽  
Vol 58 (1) ◽  
pp. 363-406 ◽  
Author(s):  
Céline Péroux ◽  
J. Christopher Howk
Keyword(s):  
Star Formation ◽  
Mass Density ◽  
Formation Rate ◽  
Cosmic Time ◽  
Dust Content ◽  
Star Formation History ◽  
Molecular Gas ◽  
Neutral Gas ◽  
Formation History ◽  
The Universe

Characterizing the relationship between stars, gas, and metals in galaxies is a critical component of understanding the cosmic baryon cycle. We compile contemporary censuses of the baryons in collapsed structures and their chemical makeup and dust content. We show the following: ▪  The [Formula: see text] mass density of the Universe is well determined to redshifts [Formula: see text] and shows minor evolution with time. New observations of molecular hydrogen reveal its evolution mirrors that of the global star-formation rate density, implying a universal cosmic molecular gas depletion timescale. The low-redshift decline of the star-formation history is thus driven by the lack of molecular gas supply due to a drop in net accretion rate related to the decreased growth of dark matter halos. ▪  The metal mass density in cold gas ([Formula: see text] K) contains virtually all the metals produced by stars for [Formula: see text]. At lower redshifts, the contributors to the total amount of metals are more diverse; at [Formula: see text], most of the observed metals are bound in stars. Overall, there is little evidence for a “missing metals problem” in modern censuses. ▪  We characterize the dust content of neutral gas over cosmic time, finding the dust-to-gas and dust-to-metals ratios fall with decreasing metallicity. We calculate the cosmological dust mass density in the neutral gas up to [Formula: see text]. There is good agreement between multiple tracers of the dust content of the Universe.

scholarly journals Modelling Stellar Populations at High Redshift

2010 ◽  
Vol 6 (S277) ◽  
pp. 158-165
Author(s):  
Claudia Maraston
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Stellar Populations ◽  
Star Formation History ◽  
Population Modelling ◽  
Massive Galaxies ◽  
Star Forming ◽  
Formation History ◽  
Derived Properties ◽  
Stellar Masses

AbstractStellar populations carry information about the formation of galaxies and their evolution up to the present epoch. A wealth of observational data are available nowadays, which are analysed with stellar population models in order to obtain key properties such as ages, star formation histories, stellar masses. Differences in the models and/or in the assumptions regarding the star formation history affect the derived properties as much as differences in the data. I shall review the interpretation of high-redshift galaxy data from a model perspective. While data quality dominates galaxy analysis at the highest possible redshifts (z > 5), population modelling effects play the major part at lower redshifts. In particular, I discuss the cases of both star-forming galaxies at the peak of the cosmic star formation history as well as passive galaxies at redshift below 1 that are often used as cosmological probes. Remarks on the bridge between low and high-z massive galaxies conclude the contribution.

scholarly journals Stellar Populations and the Star Formation Histories of LSB Galaxies—Part I: Optical and HαImaging

2011 ◽  
Vol 2011 ◽  
pp. 1-18 ◽  
Author(s):  
James Schombert ◽  
Tamela Maciel ◽  
Stacy McGaugh
Keyword(s):  
Star Formation ◽  
Data Storage ◽  
Star Formation History ◽  
Star Forming ◽  
Reduction Techniques ◽  
Formation History ◽  
History Of ◽  
Star Formation Histories ◽  
Baryonic Mass ◽  
Lsb Galaxies

This paper presents optical and Hαimaging for a large sample of LSB galaxies selected from the PSS-II catalogs (Schombert et al., 1992). As noted in previous work, LSB galaxies span a range of luminosities () and sizes (), although they are consistent in their irregular morphology. Their Hαluminosities (L(Hα)) range from 1036to 1041 ergs s−1(corresponding to a range in star formation, using canonical prescriptions, from 10−5to 1  yr−1). Although their optical colors are at the extreme blue edge for galaxies, they are similar to the colors of dwarf galaxies (Van Zee, 2001) and gas-rich irregulars (Hunter and Elmegreen, 2006). However, their star formation rates per unit stellar mass are a factor of ten less than other galaxies of the same baryonic mass, indicating that they are not simply quiescent versions of more active star-forming galaxies. This paper presents the data, reduction techniques, and new philosophy of data storage and presentation. Later papers in this series will explore the stellar population and star formation history of LSB galaxies using this dataset.

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.

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