Episodic model for star formation history and chemical abundances in giant and dwarf galaxies

Debsarma, Suma; Chattopadhyay, Tanuka; Das, Sukanta; Pfenniger, D.

doi:10.1093/mnras/stw1909

Cited by 8 publications

(5 citation statements)

References 38 publications

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“…Optical ) and near-IR imaging (Lagos et al 2011, and references therein) have also convincingly shown that these dwarf starburst galaxies possess underlying old populations. Simulations also show the episodic nature of star-forming galaxies, particularly at low masses (see, e.g., Pelupessy et al 2004;Debsarma et al 2016), thus making three episodes the simplest choice in this scenario.…”

Section: Introductionmentioning

confidence: 99%

Stellar populations of HII galaxies

Telles

Melnick

2018

A&A

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Aims. We present a UV to mid-IR spectral energy distribution (SED) study of a large sample of SDSS DR13 HII galaxies. These galaxies are selected as starbursts (EW(Hα) > 50Å) and for their high-excitation locus in the upper left region of the BPT diagram. Their photometry was derived from the cross-matched GALEX, SDSS, UKDISS, and WISE catalogs. Methods. We used CIGALE modeling and a SED fitting routine with the parametrization of a three-burst star formation history, and a comprehensive analysis of all other model parameters. We were able to estimate the contribution of the underlying old stellar population to the observed equivalent width of Hβ, and allow for more accurate burst age determination. Results. We found that the star formation histories of HII Galaxies can be reproduced remarkably well by three major eras of star formation. In addition, the SED fitting results indicate that in all cases the current burst produces a small percent of the total stellar mass, i.e., the bulk of stellar mass in HII galaxies has been produced by the past episodes of star formation, and also indicate that at a given age the Hβ luminosity depends only on the mass of young stars favoring a universal IMF for massive stars. Most importantly, the current star formation episodes are maximum starbursts that produce stars at the highest possible rate.

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Section: Introductionmentioning

confidence: 99%

Stellar populations of HII galaxies

Telles

Melnick

2018

A&A

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“…Optical ) and near-IR imaging (Lagos et al 2011, and references therein) have also convincingly shown that these dwarf starburst galaxies possess underlying old populations. Simulations also show the episodic nature of star forming galaxies, particularly at low masses (see e.g Pelupessy et al 2004;Debsarma et al 2016), being three episodes the simplest choice in this scenario.…”

Section: Introductionmentioning

confidence: 90%

The Stellar Populations of HII galaxies: A tale of three bursts

Telles,

Melnick

2018

Preprint

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Aims. We present a UV to mid-IR spectral energy distribution study of a large sample of SDSS DR13 HII galaxies. These are selected as starburst (EW(Hα) > 50Å) and for their high excitation locus in the upper-left region of the BPT diagram. Their photometry was derived from the cross-matched GALEX, SDSS, UKDISS and WISE catalogues. Methods. We have used CIGALE modelling and SED fitting routine with the parametrization of a three burst star formation history, and a comprehensive analysis of all other model parameters. We have been able to estimate the contribution of the underlying old stellar population to the observed equivalent width of Hβ and allow for more accurate burst age determination. Results. We found that the star formation histories of HII Galaxies can be reproduced remarkably well by three major eras of star formation. In addition, the SED fitting results indicate that: i) in all cases the current burst produces less than a few percent of the total stellar mass: the bulk of stellar mass in HII galaxies have been produced by the past episodes of star formation; ii) at a given age the Hβ luminosity depends only on the mass of young stars favouring a universal IMF for massive stars; iii) the current star formation episodes are maximal starbursts, producing stars at the highest possible rate.

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“…In addition we have also considered Gaussian Mixture Model (2 and 3 modes) following the episodic nature of star formation (Hernandez et al 1999, Stinson et al 2007, Tremblay et al 2010, Huang et al 2013, Debsarma et al 2016, Cignoni et al 2018, Das et al 2020 and Beta distribution following unimodal star formation history in many giant galaxies.…”

Section: Various Star Formation Historiesmentioning

confidence: 99%

“…where p, q > 0 are respectively the rising and falling slope of SFH over time and B(p, q) = Γ(p)Γ(q) Γ(p+q) , where Γ is the Gamma function. Unimodal star formation rate (SFR(t)) has been seen in many giant galaxies (Debsarma et al 2016, Feldmann 2017, Das et al 2020 under various parametric conditions. Here we consider the values of (p, q) as (2, 2) and (5, 1) respectively.…”

Section: Beta Distribution Of Sfr(t)mentioning

confidence: 99%

Exploration about the origin of galactic and extragalactic star clusters through simulated H-R diagrams

Chattopadhyay,

Mondal,

Paul

et al. 2020

Preprint

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The present work explores the origin of the formation of star clusters in our Galaxy and in Small Magellanic Cloud (SMC) through simulated H−R diagrams and compare those with observed star clusters. The simulation study produces synthetic H−R diagrams by Markov Chain Monte Carlo (MCMC) technique using star formation history (SFH), luminosity function (LF), abundance of heavy metal (Z) and a big library of isochrones as basic inputs and compares them with observed H−R diagrams of various star clusters. The distance based comparison between those two diagrams is carried out through two dimensional matching of points in Color−Magnitude Diagram (CMD) after optimal choice of bin size and appropriate distance function. It is found that a poor medium of heavy elements (Z = 0.0004), Gaia LF along with mixture of multiple Gaussian distributions of SFH may be the origin of formation of globular clusters (GCs). On the contrary, enriched medium (Z = 0.019) is favoured with Gaia LF along with double power law (i.e. unimodal) SFH. For SMC clusters, the choice of exponential LF and exponential SFH is a proper combination for poor medium whereas Gaia LF with Beta type SFH is preferred in an enriched medium for the formation of star clusters.

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Episodic model for star formation history and chemical abundances in giant and dwarf galaxies

Cited by 8 publications

References 38 publications

Stellar populations of HII galaxies

Stellar populations of HII galaxies

The Stellar Populations of HII galaxies: A tale of three bursts

Exploration about the origin of galactic and extragalactic star clusters through simulated H-R diagrams

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