scholarly journals Galaxy Metabolism

2010 ◽  
Vol 27 (3) ◽  
pp. 233-233
Author(s):  
Andrew Hopkins
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Mass Density ◽  
High Redshift ◽  
Large Population ◽  
Star Formation History ◽  
Global Constraints ◽  
Great Success ◽  
Mass Dependent ◽  
Cosmic History

‘Galaxy Metabolism' was the second in the annual ‘Southern Cross Astrophysics Conference Series’ (http://www.aao.gov.au/AAO/southerncross/), supported by the Anglo-Australian Observatory and the Australia Telescope National Facility. It was held at the Australian National Maritime Museum in Darling Harbour, Sydney, from 22 to 26 June 2009, and was attended by 91 delegates from around the world.Over the past decade, both the star formation history and stellar mass density in galaxies spanning most of cosmic history have been well constrained. This provides the backdrop and framework within which many detailed investigations of galaxy growth are now placed. The mass-dependent and environment-dependent evolution of galaxies over cosmic history is now the focus of several surveys. Many studies are also exploring the role of gas infall and outflow in driving galaxy evolution, and the connection of these processes to massive star formation within galaxies.The aims of ‘Galaxy Metabolism’ were to bring together the global constraints on galaxy evolution, at both low and high redshift, with detailed studies of well-resolved systems, to define a clear picture of our understanding of galaxy metabolism: How do the processes of ingestion (infall), digestion (ISM physics, star formation) and excretion (outflow) govern the global properties of galaxies; how do these change over a galaxy's lifetime; and are the constraints from nearby well resolved studies consistent with those from large population surveys at low and high redshift?The conference was a great success, with an extensive variety of topics covered spanning many aspects of galaxy evolution, and brought together eloquently in a comprehensive conference summary by Warrick Couch. The four papers by De Lucia (2010), Cole (2010), Vlajić (2010) and Stocke et al. (2010) presented in this special collection of PASA are just a sampling of the depth and variety of the resentations given during the conference.

scholarly journals CALIFA survey: The spatially resolved star formation history of massive galaxies

2012 ◽  
Vol 8 (S295) ◽  
pp. 300-303
Author(s):  
Rosa González Delgado ◽  
Enrique Pérez ◽  
Roberto Cid Fernandes ◽  
Rubén García-Benito ◽  
André de Amorim ◽  
...  
Keyword(s):  
Growth Rate ◽  
Star Formation ◽  
Galaxy Evolution ◽  
Local Density ◽  
Spectral Synthesis ◽  
Mass Density ◽  
Stellar Mass ◽  
Star Formation History ◽  
Formation History ◽  
History Of

AbstractThe Calar Alto Legacy Integral Field Area (CALIFA) project is an ongoing 3D spectroscopic survey of 600 nearby galaxies of all kinds. This pioneer survey is providing valuable clues on how galaxies form and evolve. Processed through spectral synthesis techniques, CALIFA datacubes allow us to, for the first time, spatially resolve the star formation history of galaxies spread across the color-magnitude diagram. The richness of this approach is already evident from the results obtained for the first ~ 1/6 of the sample. Here we show how the different galactic spatial sub-components (“bulge” and “disk”) grow their stellar mass over time. We explore the results stacking galaxies in mass bins, finding that, except at the lowest masses, galaxies grow inside-out, and that the growth rate depends on a galaxy's mass. The growth rate of inner and outer regions differ maximally at intermediate masses. We also find a good correlation between the age radial gradient and the stellar mass density, suggesting that the local density is a main driver of galaxy evolution.

scholarly journals Initial Model Catalogue for Galaxy Evolution

2004 ◽  
Vol 21 (2) ◽  
pp. 171-174 ◽  
Author(s):  
Naohito Nakasato
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Milky Way ◽  
High Redshift ◽  
Random Number Generator ◽  
Star Formation History ◽  
Initial Model ◽  
Model Galaxy ◽  
Formation History ◽  
Type Ia

AbstractWe have computed full hydrochemodynamical evolution for 150 initial models of protogalaxies with our chemodynamical SPH code named GENSO. Various parameters for all models are identical except for a seed for a random number generator. In other words, all models have similar global properties but have the different merging history that leads to a different evolution in each model. Results of the series of computations have two main applications. Firstly, we have an initial model catalogue for subsequent modelling of galaxy evolution. Since the resulting evolution depends strongly on the initial phase of the particle distribution, it is crucial to find a suitable initial model when we model a specific real galaxy in the Universe, notably the Milky Way in our case. We will make a precise chemical and dynamical model of the Milky Way out of 150 models in our initial model catalogue. Secondly, we can obtain a large variety of global histories of physical values such as star formation, metallicity in the ISM and stellar components, and Type II and Ia supernova rates. For example, the resulting total star formation history shows the peak at a high redshift z ∼ 6 and the peak value is ∼280 M⊙ yr–1 Mpc–3. Also, the Type Ia rate obtained has a peak at z ∼ 3.5. All of our results and model catalogue are publicly available from our website for those who wish to model galaxy evolution.

scholarly journals The Imprints Of Galactic Environment On Cluster Formation and Evolution

2015 ◽  
Vol 12 (S316) ◽  
pp. 17-24
Author(s):  
Angela Adamo
Keyword(s):  
Star Formation ◽  
Formation Process ◽  
Globular Clusters ◽  
High Redshift ◽  
Cluster Formation ◽  
Large Population ◽  
Star Clusters ◽  
Young Star ◽  
Star Formation History ◽  
Formation History

AbstractYoung star clusters (YSCs) appear to be a ubiquitous product of star formation in local galaxies, thus, they can be used to study the star formation process at work in their host galaxies. Moreover, YSCs are intrinsically brighter that single stars, potentially becoming the most important tracers of the recent star formation history in galaxies in the local Universe. In local galaxies, we also witness the presence of a large population of evolved star clusters, commonly called globular clusters (GCs). GCs peak formation history is very close to the redshift (z ~ 2) when the cosmic star formation history reached the maximum. Therefore, GCs are usually associated to extreme star formation episodes in high-redshift galaxies. It is yet not clear whether YSCs and GCs share a similar formation process (same physics under different interstellar medium conditions) and evolution process, and whether the former can be used as progenitor analogs of the latter. In this invited contribution, I review general properties of YSC populations in local galaxies. I will summarise some of the current open questions in the field, with particular emphasis to whether or not galactic environments, where YSCs form, leave imprints on the nested populations. The importance of this rapidly developing field can be crucial in understanding GC formation and possibly the galactic environment condition where this ancient population formed.

scholarly journals The impact of the FMR and starburst galaxies on the (low-metallicity) cosmic star formation history

2021 ◽  
Author(s):  
Martyna Chruślińska ◽  
Gijs Nelemans ◽  
Lumen Boco ◽  
Andrea Lapi
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Formation Rate ◽  
Starburst Galaxies ◽  
Star Formation History ◽  
Formation History ◽  
Low Metallicity ◽  
Dependent Mass ◽  
The Impact ◽  
Cosmic History

Abstract The question how much star formation is occurring at low metallicity throughout the cosmic history appears crucial for the discussion of the origin of various energetic transients, and possibly - double black hole mergers. We revisit the observation-based distribution of birth metallicities of stars (fSFR(Z,z)), focusing on several factors that strongly affect its low metallicity part: (i) the method used to describe the metallicity distribution of galaxies (redshift-dependent mass metallicity relation - MZR, or redshift-invariant fundamental metallicity relation - FMR), (ii) the contribution of starburst galaxies and (iii) the slope of the MZR. We empirically construct the FMR based on the low-redshift scaling relations, which allows us to capture the systematic differences in the relation caused by the choice of metallicity and star formation rate (SFR) determination techniques and discuss the related fSFR(Z,z) uncertainty. We indicate factors that dominate the fSFR(Z,z) uncertainty in different metallicity and redshift regimes. The low metallicity part of the distribution is poorly constrained even at low redshifts (even a factor of ∼200 difference between the model variations) The non-evolving FMR implies a much shallower metallicity evolution than the extrapolated MZR, however, its effect on the low metallicity part of the fSFR(Z,z) is counterbalanced by the contribution of starbursts (assuming that they follow the FMR). A non-negligible fraction of starbursts in our model may be necessary to satisfy the recent high-redshift SFR density constraints.

scholarly journals Quasi-equilibrium models of high-redshift disc galaxy evolution

2020 ◽  
Vol 500 (3) ◽  
pp. 3394-3412
Author(s):  
Steven R Furlanetto
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
High Redshift ◽  
Formation Rate ◽  
New Physics ◽  
Small Scale ◽  
Quasi Equilibrium ◽  
Mass Relation ◽  
Disc Galaxy

ABSTRACT In recent years, simple models of galaxy formation have been shown to provide reasonably good matches to available data on high-redshift luminosity functions. However, these prescriptions are primarily phenomenological, with only crude connections to the physics of galaxy evolution. Here, we introduce a set of galaxy models that are based on a simple physical framework but incorporate more sophisticated models of feedback, star formation, and other processes. We apply these models to the high-redshift regime, showing that most of the generic predictions of the simplest models remain valid. In particular, the stellar mass–halo mass relation depends almost entirely on the physics of feedback (and is thus independent of the details of small-scale star formation) and the specific star formation rate is a simple multiple of the cosmological accretion rate. We also show that, in contrast, the galaxy’s gas mass is sensitive to the physics of star formation, although the inclusion of feedback-driven star formation laws significantly changes the naive expectations. While these models are far from detailed enough to describe every aspect of galaxy formation, they inform our understanding of galaxy formation by illustrating several generic aspects of that process, and they provide a physically grounded basis for extrapolating predictions to faint galaxies and high redshifts currently out of reach of observations. If observations show violations from these simple trends, they would indicate new physics occurring inside the earliest generations of galaxies.

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 Theoretical considerations for star formation at low and high redshift

2015 ◽  
Vol 11 (S315) ◽  
pp. 247-253
Author(s):  
Bruce G. Elmegreen
Keyword(s):  
Star Formation ◽  
Mass Density ◽  
High Redshift ◽  
Distribution Functions ◽  
High Mass ◽  
Formation Processes ◽  
Accretion Rates ◽  
Major Merger ◽  
Cloud Cores ◽  
Self Gravity

AbstractStar formation processes in strongly self-gravitating cloud cores should be similar at all redshifts, forming single or multiple stars with a range of masses determined by local magneto-hydrodynamics and gravity. The formation processes for these cores, however, as well as their structures, temperatures, Mach numbers, etc., and the boundedness and mass distribution functions of the resulting stars, should depend on environment, as should the characteristic mass, density, and column density at which cloud self-gravity dominates other forces. Because the environments for high and low redshift star formation differ significantly, we expect the resulting gas to stellar conversion details to differ also. At high redshift, the universe is denser and more gas-rich, so the active parts of galaxies are denser and more gas rich too, leading to slightly shorter gas consumption timescales, higher cloud pressures, and denser, more massive, bound stellar clusters at the high mass end. With shorter consumption times corresponding to higher relative cosmic accretion rates, and with the resulting higher star formation rates and their higher feedback powers, the ISM has greater turbulent speeds relative to the rotation speeds, thicker gas disks, and larger cloud and star complex sizes at the characteristic Jeans length. The result is a more chaotic appearance at high redshift, bridging the morphology gap between today's quiescent spirals and today's major-mergers, with neither spiral nor major-merger processes actually in play at that time. The result is also a thick disk at early times, and after in-plane accretion from relatively large clump torques, a classical bulge. Today's disks are thinner, and torque-driven accretion is slower outside of inner barred regions. This paper reviews the basic processes involved with star formation in order to illustrate its evolution over time and environment.

scholarly journals Dissecting the Formation Histories of Galaxies with Stellar Populations Models

2009 ◽  
Vol 5 (S262) ◽  
pp. 153-163
Author(s):  
Ivo Labbé
Keyword(s):  
Star Formation ◽  
Current Knowledge ◽  
High Redshift ◽  
Local Environment ◽  
Stellar Populations ◽  
Current Data ◽  
Star Formation History ◽  
Spectral Energy ◽  
Formation History ◽  
History Of

AbstractHow did galaxies evolve from primordial fluctuations to the well-ordered but diverse population of disk and elliptical galaxies that we observe today? Stellar populations synthesis models have become a crucial tool in addressing this question by helping us to interpret the spectral energy distributions of present-day galaxies and their high redshift progenitors in terms of fundamental characteristics such as stellar mass and age. I will review our current knowledge on the evolution of stellar populations in early- and late type galaxies at z < 1 and the tantalizing – but incomplete – view of the stellar populations in galaxies at 1 < z < 3, during the global peak of star formation. Despite great progress, many fundamental questions remain: what processes trigger episodes of galaxy-scale star formation and what quenches them? To what degree does the star formation history of galaxies depend on the merger history, (halo) mass, or local environment? I will discuss some of the challenges posed in interpreting current data and what improved results might be expected from new observational facilities in the near- and more distant future.

scholarly journals A Photometric Survey of Field Stars in the Large Magellanic Cloud: Probing its Star-Formation History

1999 ◽  
Vol 190 ◽  
pp. 343-344 ◽  
Author(s):  
T. A. Smecker-Hane ◽  
J. S. Gallagher ◽  
Andrew Cole ◽  
P. B. Stetson ◽  
E. Tolstoy
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Stellar Population ◽  
Formation Rate ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Star Formation History ◽  
Wide Field ◽  
Formation History ◽  
Magnitude Diagram

The Large Magellanic Cloud (LMC) is unique among galaxies in the Local Group in that it is the most massive non-spiral, is relatively gas-rich, and is actively forming stars. Determining its star-formation rate (SFR) as a function of time will be a cornerstone in our understanding of galaxy evolution. The best method of deriving a galaxy's past SFR is to compare the densities of stars in a color-magnitude diagram (CMD), a Hess diagram, with model Hess diagrams. The LMC has a complex stellar population with ages ranging from 0 to ~ 14 Gyr and metallicities from −2 ≲ [Fe/H] ≲ −0.4, and deriving its SFR and simultaneously constraining model input parameters (distance, age-metallicity relation, reddening, and stellar models) requires well-populated CMDs that span the magnitude range 15 ≤ V ≤ 24. Although existing CMDs of field stars in the LMC show tantalizing evidence for a significant burst of star formation that occurred ~ 3 Gyr ago (for examples, see Westerlund et al. 1995; Vallenari et al. 1996; Elson, et al. 1997; Gallagher et al. 1999, and references therein), estimates of the enhancement in the SFR vary from factors of 3 to 50. This uncertainty is caused by the relatively large photometric errors that plague crowded ground-based images, and the small number statistics that plague CMDs created from single Wide Field Planetary Camera 2 (WFPC2) images.

scholarly journals Galaxy And Mass Assembly (GAMA): a forensic SED reconstruction of the cosmic star formation history and metallicity evolution by galaxy type

2020 ◽  
Vol 498 (4) ◽  
pp. 5581-5603
Author(s):  
Sabine Bellstedt ◽  
Aaron S G Robotham ◽  
Simon P Driver ◽  
Jessica E Thorne ◽  
Luke J M Davies ◽  
...  
Keyword(s):  
Star Formation ◽  
Gas Phase ◽  
Mass Density ◽  
Spectral Energy Distribution ◽  
Stellar Mass ◽  
Star Formation History ◽  
Spectral Energy ◽  
Massive Galaxies ◽  
Formation History ◽  
The Universe

ABSTRACT We apply the spectral energy distribution (SED) fitting code ProSpect to multiwavelength imaging for ∼7000 galaxies from the GAMA survey at z &lt; 0.06, in order to extract their star formation histories. We combine a parametric description of the star formation history with a closed-box evolution of metallicity where the present-day gas-phase metallicity of the galaxy is a free parameter. We show with this approach that we are able to recover the observationally determined cosmic star formation history (CSFH), an indication that stars are being formed in the correct epoch of the Universe, on average, for the manner in which we are conducting SED fitting. We also show the contribution to the CSFH of galaxies of different present-day visual morphologies and stellar masses. Our analysis suggests that half of the mass in present-day elliptical galaxies was in place 11 Gyr ago. In other morphological types, the stellar mass formed later, up to 6 Gyr ago for present-day irregular galaxies. Similarly, the most massive galaxies in our sample were shown to have formed half their stellar mass by 11 Gyr ago, whereas the least massive galaxies reached this stage as late as 4 Gyr ago (the well-known effect of ‘galaxy downsizing’). Finally, our metallicity approach allows us to follow the average evolution in gas-phase metallicity for populations of galaxies and extract the evolution of the cosmic metal mass density in stars and in gas, producing results in broad agreement with independent, higher redshift observations of metal densities in the Universe.

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