scholarly journals The time delay between star formation quenching and morphological transformation of galaxies in clusters: a phase–space view of EDisCS

2019 ◽  
Vol 486 (1) ◽  
pp. 868-884 ◽  
Author(s):  
Kshitija Kelkar ◽  
Meghan E Gray ◽  
Alfonso Aragón-Salamanca ◽  
Gregory Rudnick ◽  
Yara L Jaffé ◽  
...  
Keyword(s):  
Star Formation ◽  
Phase Space ◽  
Structural Parameters ◽  
Imaging Data ◽  
Morphological Transformation ◽  
Star Forming ◽  
Cluster Environment ◽  
Cluster Cores ◽  
Two Parameters ◽  
Star Formation Histories

Abstract We explore the possible effect of cluster environments on the structure and star formation histories of galaxies by analysing the projected phase–space (PPS) of intermediate-redshift clusters (0.4 ≤ z ≤ 0.8). HST I−band imaging data from the ESO Distant Cluster Survey (EDisCS) allow us to measure deviations of the galaxies’ light distributions from symmetric and smooth profiles using two parameters, Ares (‘asymmetry’) and RFF (residual flux fraction or ‘roughness’). Combining these structural parameters with age-sensitive spectral indicators ($H_{\delta \rm {A}}$, $H_{\gamma \rm {A}}$, and Dn4000), we establish that in all environments younger star-forming galaxies of all morphologies are ‘rougher’ and more asymmetric than older, more quiescent ones. Combining a subset of the EDisCS clusters, we construct a stacked PPS diagram and find a significant correlation between the position of the galaxies on the PPS and their stellar ages, irrespective of their morphology. We also observe an increasing fraction of galaxies with older stellar populations towards the cluster core, while the galaxies’ structural parameters (Ares and RFF) do not seem to segregate strongly with PPS. These results may imply that, under the possible influence of their immediate cluster environment, galaxies have their star formation suppressed earlier, while their structural transformation happens on a longer time-scale as they accumulate and age in the cluster cores.

Evolution histories of massive galaxies at z∼2 over the past 3 Gyr

2019 ◽  
Vol 15 (S341) ◽  
pp. 50-54
Author(s):  
T. Morishita ◽  
L. E. Abramson ◽  
T. Treu ◽  
G. B. Brammer ◽  
T. Jones ◽  
...  
Keyword(s):  
Star Formation ◽  
Gas Phase ◽  
Early Type ◽  
Imaging Data ◽  
Data Set ◽  
Massive Galaxies ◽  
Star Forming ◽  
The Past ◽  
Star Formation Histories

AbstractWe study star formation and metallicity enrichment histories of 24 massive galaxies at 1.6 < z < 2.5. Deep slitless spectroscopy + imaging data set collected from multiple HST surveys allows robust determination of their SEDs. Our new SED modeling with no functional assumptions on star formation histories revels that 1. most of the sample galaxies have already formed >50% of their extant masses ∼1.5 Gyr before the time of observed redshifts, with a trend where more massive galaxies form earlier, 2. most of our galaxies already have stellar metallicities compatible with those of local early-type galaxies, and 3. inferred metallicities are on average ∼ 0.25 dex higher than observed gas-phase metallicities of star forming galaxies at the time of their formation. Continuation of low-level star formation, rather than abrupt termination of star forming activity, may explain the observed gap of metallicities.

scholarly journals The effects of star formation history in the SFR–M* relation of H ii galaxies

2020 ◽  
Vol 500 (3) ◽  
pp. 3240-3253
Author(s):  
Amanda R Lopes ◽  
Eduardo Telles ◽  
Jorge Melnick
Keyword(s):  
Star Formation ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Star Formation History ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
Good Tool ◽  
Star Forming ◽  
Additional Information ◽  
Star Formation Histories

ABSTRACT We discuss the implications of assuming different star formation histories (SFH) in the relation between star formation rate (SFR) and mass derived by the spectral energy distribution fitting (SED). Our analysis focuses on a sample of H ii galaxies, dwarf starburst galaxies spectroscopically selected through their strong narrow emission lines in SDSS DR13 at z &lt; 0.4, cross-matched with photometric catalogues from GALEX, SDSS, UKIDSS, and WISE. We modelled and fitted the SEDs with the code CIGALE adopting different descriptions of SFH. By adding information from different independent studies, we find that H ii galaxies are best described by episodic SFHs including an old (10 Gyr), an intermediate age (100−1000 Myr) and a recent population with ages &lt; 10 Myr. H ii galaxies agree with the SFR−M* relation from local star-forming galaxies, and only lie above such relation when the current SFR is adopted as opposed to the average over the entire SFH. The SFR−M* demonstrated not to be a good tool to provide additional information about the SFH of H ii galaxies, as different SFH present a similar behaviour with a spread of &lt;0.1 dex.

scholarly journals A new method to derive star formation histories in dwarf galaxies

2018 ◽  
Vol 14 (S344) ◽  
pp. 267-270
Author(s):  
Marius Čeponis ◽  
Rima Stonkutė ◽  
Vladas Vansevičius
Keyword(s):  
Star Formation ◽  
New Method ◽  
Star Forming ◽  
Stellar Photometry ◽  
Star Forming Regions ◽  
Density Maps ◽  
Irregular Galaxies ◽  
Star Formation Histories ◽  
Dwarf Irregular Galaxies ◽  
Inside Out

AbstractWe present a new method to derive 2D star formation histories in dwarf irregular galaxies. Based on multicolor stellar photometry data we have found that in the Leo A galaxy during the last ∽400 Myr star formation was propagating according to the inside-out scenario. Star-forming regions have spread strongly asymmetrically from the center and their present day distribution correlates well with the Hi surface density maps.

scholarly journals A redshift-dependent IRX–β dust attenuation relation for TNG50 galaxies

2020 ◽  
Vol 497 (4) ◽  
pp. 4773-4794 ◽  
Author(s):  
Sebastian Schulz ◽  
Gergö Popping ◽  
Annalisa Pillepich ◽  
Dylan Nelson ◽  
Mark Vogelsberger ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Main Sequence ◽  
Infrared Excess ◽  
Star Forming ◽  
Dust Composition ◽  
Metal Ratio ◽  
Stellar Masses ◽  
Dust Attenuation ◽  
Star Formation Histories

ABSTRACT We study the relation between the UV slope, β, and the ratio between the infrared- and UV luminosities (IRX) of galaxies from TNG50, the latest installment of the IllustrisTNG galaxy formation simulations. We select 7280 star-forming main-sequence (SFMS) galaxies with stellar mass ≥109 M⊙ at redshifts 0 ≤ z ≤ 4 and perform radiative transfer with skirt to model effects of interstellar medium dust on the emitted stellar light. Assuming a Milky Way dust type and a dust-to-metal ratio of 0.3, we find that TNG50 SFMS galaxies generally agree with observationally derived IRX–β relations at z ≲ 1. However, we find a redshift-dependent systematic offset with respect to empirically derived local relations, with the TNG50 IRX–β relation shifting towards lower β and steepening at higher redshifts. This is partially driven by variations in the dust-uncorrected UV slope of galaxies, due to different star formation histories of galaxies selected at different cosmic epochs; we suggest the remainder of the effect is caused by differences in the effective dust attenuation curves of galaxies as a function of redshift. We find a typical galaxy-to-galaxy variation of 0.3 dex in infrared excess (IRX) at fixed β, correlated with intrinsic galaxy properties: galaxies with higher star formation rates, star formation efficiencies, gas metallicities and stellar masses exhibit larger IRX values. We demonstrate a degeneracy between stellar age, dust geometry, and dust composition: z = 4 galaxies with a Small Magellanic Cloud dust type follow the same IRX–β relation as low-redshift galaxies with MW dust. We provide a redshift-dependent fitting function for the IRX–β relation for MW dust based on our models.

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 What is Important? Morphological Asymmetries are Useful Predictors of Star Formation Rates of Star-forming Galaxies in SDSS Stripe 82

2021 ◽  
Vol 923 (2) ◽  
pp. 205
Author(s):  
Hassen M. Yesuf ◽  
Luis C. Ho ◽  
S. M. Faber
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
Imaging Data ◽  
Galaxy Interactions ◽  
Star Forming ◽  
Sky Survey ◽  
Structural Variables ◽  
Central Concentration

Abstract The morphology and structure of galaxies reflect their star formation and assembly histories. We use the framework of mutual information (MI) to quantify the interdependence among several structural variables and to rank them according to their relevance for predicting the specific star formation rate (SSFR) by comparing the MI of the predictor variables with the SSFR and penalizing variables that are redundant. We apply this framework to study ∼3700 face-on star-forming galaxies (SFGs) with varying degrees of bulge dominance and central concentration and with stellar mass M ⋆ ≈ 109 M ⊙−5 × 1011 M ⊙ at redshift z = 0.02–0.12. We use the Sloan Digital Sky Survey (SDSS) Stripe 82 deep i-band imaging data, which improve measurements of asymmetry and bulge dominance indicators. We find that star-forming galaxies are a multiparameter family. In addition to M ⋆, asymmetry emerges as the most powerful predictor of SSFR residuals of SFGs, followed by bulge prominence/concentration. Star-forming galaxies with higher asymmetry and stronger bulges have higher SSFR at a given M ⋆. The asymmetry reflects both irregular spiral arms and lopsidedness in seemingly isolated SFGs and structural perturbations by galaxy interactions or mergers.

scholarly journals The EDGE-CALIFA survey: Self-regulation of Star formation at kpc scales

2021 ◽  
Author(s):  
J K Barrera-Ballesteros ◽  
S F Sánchez ◽  
T Heckman ◽  
T Wong ◽  
A Bolatto ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Self Regulation ◽  
Stellar Mass ◽  
Good Representation ◽  
Star Forming ◽  
Star Forming Regions ◽  
Wide Range ◽  
Two Parameters ◽  
Stellar Masses

Abstract The processes that regulate star formation are essential to understand how galaxies evolve. We present the relation between star formation rate density, ΣSFR , and hydrostatic midplane pressure, Ph , for 4260 star-forming regions of kpc size located in 96 galaxies included in the EDGE-CALIFA survey covering a wide range of stellar masses and morphologies. We find that these two parameters are tightly correlated, showing a smaller scatter in comparison to other star-forming relations. A power-law, with a slightly sub-linear index, is a good representation of this relation. Its residuals show a significant anti-correlation with both stellar age and metallicity whereas the total stellar mass may also play a secondary role in shaping the ΣSFR - Ph relation. For actively star-forming regions we find that the effective feedback momentum per unit stellar mass (p*/m*), measured from the Ph/ΣSFR ratio increases with Ph. The median value of this ratio for all the sampled regions is larger than the expected momentum just from supernovae explosions. Morphology of the galaxies, including bars, does not seem to have a significant impact in the ΣSFR - Ph relation. Our analysis indicates that local ΣSFR self-regulation comes mainly from momentum injection to the interstellar medium from supernovae explosions. However, other mechanisms in disk galaxies may also play a significant role in shaping the ΣSFR at kpc scales. Our results also suggest that Ph is the main parameter that modulates star formation at kpc scales, rather than individual components of the baryonic mass.

scholarly journals Star Formation Histories of the LEGUS Dwarf Galaxies. III. The Nonbursty Nature of 23 Star-forming Dwarf Galaxies

2019 ◽  
Vol 887 (2) ◽  
pp. 112 ◽  
Author(s):  
M. Cignoni ◽  
E. Sacchi ◽  
M. Tosi ◽  
A. Aloisi ◽  
D. O. Cook ◽  
...  
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Star Forming ◽  
Star Formation Histories

scholarly journals Rejuvenated galaxies with very old bulges at the origin of the bending of the main sequence and of the ‘green valley’

2019 ◽  
Vol 489 (1) ◽  
pp. 1265-1290 ◽  
Author(s):  
Chiara Mancini ◽  
Emanuele Daddi ◽  
Stéphanie Juneau ◽  
Alvio Renzini ◽  
Giulia Rodighiero ◽  
...  
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Formation Rate ◽  
Very Old ◽  
Massive Galaxies ◽  
Star Forming ◽  
Late Event ◽  
Age Of The Universe ◽  
Stellar Masses ◽  
Star Formation Histories

ABSTRACT We investigate the nature of star-forming galaxies with reduced specific star formation rate (sSFR) and high stellar masses, those ‘green valley’ objects that seemingly cause a reported bending, or flattening, of the star-forming main sequence. The fact that such objects host large bulges recently led some to suggest that the internal formation of bulges was a late event that induced the sSFRs of massive galaxies to drop in a slow downfall, and thus the main sequence to bend. We have studied in detail a sample of 10 galaxies at 0.45 &lt; z &lt; 1 with secure SFR from Herschel, deep Keck optical spectroscopy, and HST imaging from CANDELS allowing us to perform multiwavelength bulge to disc decomposition, and to derive star formation histories for the separated bulge and disc components. We find that the bulges hosted in these systems below main sequence are virtually all maximally old, with ages approaching the age of the Universe at the time of observation, while discs are young (〈 T50〉 ∼ 1.5 Gyr). We conclude that, at least based on our sample, the bending of the main sequence is, for a major part, due to rejuvenation, and we disfavour mechanisms that postulate the internal formation of bulges at late times. The very old stellar ages of our bulges suggest a number density of early-type galaxies at z = 1–3 higher than actually observed. If confirmed, this might represent one of the first direct validations of hierarchical assembly of bulges at high redshifts.

Sign in / Sign up

Export Citation Format

Share Document