scholarly journals Linking compact dwarf starburst galaxies in the RESOLVE survey to downsized blue nuggets

2020 ◽  
Vol 494 (4) ◽  
pp. 4730-4750
Author(s):  
Michael L Palumbo ◽  
Sheila J Kannappan ◽  
Elaine M Frazer ◽  
Kathleen D Eckert ◽  
Dara J Norman ◽  
...  
Keyword(s):  
High Redshift ◽  
Stellar Mass ◽  
High Rate ◽  
Mass Ratio ◽  
Quantitative Criterion ◽  
Local Universe ◽  
Surface Mass ◽  
Star Forming ◽  
Number Counts ◽  
Disc Galaxies

ABSTRACT We identify and characterize compact dwarf starburst (CDS) galaxies in the REsolved Spectroscopy Of a Local VolumE (RESOLVE) survey, a volume-limited census of galaxies in the local Universe, to probe whether this population contains any residual ‘blue nuggets,’ a class of intensely star-forming compact galaxies first identified at high redshift z. Our 50 low-z CDS galaxies are defined by dwarf masses (stellar mass M* < 109.5 M⊙), compact bulged-disc or spheroid-dominated morphologies (using a quantitative criterion, $\mu _\Delta \gt 8.6$), and specific star formation rates (SSFRs) above the defining threshold for high-z blue nuggets (log  SSFR [Gyr−1] > −0.5). Across redshifts, blue nuggets exhibit three defining properties: compactness relative to contemporaneous galaxies, abundant cold gas, and formation via compaction in mergers or colliding streams. Those with halo mass below Mhalo ∼ 1011.5 M⊙ may in theory evade permanent quenching and cyclically refuel until the present day. Selected only for compactness and starburst activity, our CDS galaxies generally have Mhalo ≲ 1011.5 M⊙ and gas-to-stellar mass ratio ≳1. Moreover, analysis of archival DECaLS photometry and new 3D spectroscopic observations for CDS galaxies reveals a high rate of photometric and kinematic disturbances suggestive of dwarf mergers. The SSFRs, surface mass densities, and number counts of CDS galaxies are compatible with theoretical and observational expectations for redshift evolution in blue nuggets. We argue that CDS galaxies represent a maximally starbursting subset of traditional compact dwarf classes such as blue compact dwarfs and blue E/S0s. We conclude that CDS galaxies represent a low-z tail of the blue nugget phenomenon formed via a moderated compaction channel that leaves open the possibility of disc regrowth and evolution into normal disc galaxies.

scholarly journals Redshift evolution of the H2/H i mass ratio in galaxies

2021 ◽  
Vol 502 (1) ◽  
pp. L85-L89
Author(s):  
Laura Morselli ◽  
A Renzini ◽  
A Enia ◽  
G Rodighiero
Keyword(s):  
High Redshift ◽  
Strong Dependence ◽  
Formation Rate ◽  
Stellar Mass ◽  
Mass Ratio ◽  
Star Forming ◽  
Spatially Resolved ◽  
Internal Working ◽  
Neutral Gas ◽  
Grand Design

ABSTRACT In this paper, we present an attempt to estimate the redshift evolution of the molecular to neutral gas mass ratio within galaxies (at fixed stellar mass). For a sample of five nearby grand design spirals located on the main-sequence (MS) of star-forming galaxies, we exploit maps at 500 pc resolution of stellar mass and star formation rate (M⋆ and SFR). For the same cells, we also have estimates of the neutral (MH i) and molecular ($M_{\rm H_2}$) gas masses. To compute the redshift evolution, we exploit two relations: (i) one between the molecular-to-neutral mass ratio and the total gas mass (Mgas), whose scatter shows a strong dependence with the distance from the spatially resolved MS, and (ii) the one between $\log (M_{\rm {H_2}}/M_{\star })$ and log (MH i/M⋆). For both methods, we and that $M_{\rm H_2}$/MH i within the optical radius slightly decreases with redshift, contrary to common expectations of galaxies becoming progressively more dominated by molecular hydrogen at high redshifts. We discuss possible implications of this trend on our understanding of the internal working of high-redshift galaxies.

scholarly journals xGASS: the role of bulges along and across the local star-forming main sequence

2020 ◽  
Vol 493 (4) ◽  
pp. 5596-5605 ◽  
Author(s):  
Robin H W Cook ◽  
Luca Cortese ◽  
Barbara Catinella ◽  
Aaron Robotham
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Formation Rate ◽  
Stellar Mass ◽  
Local Universe ◽  
Star Forming ◽  
Star Formation Activity ◽  
The Galaxy ◽  
Stellar Masses

ABSTRACT We use our catalogue of structural decomposition measurements for the extended GALEX Arecibo SDSS Survey (xGASS) to study the role of bulges both along and across the galaxy star-forming main sequence (SFMS). We show that the slope in the sSFR–M⋆ relation flattens by ∼0.1 dex per decade in M⋆ when re-normalizing specifice star formation rate (sSFR) by disc stellar mass instead of total stellar mass. However, recasting the sSFR–M⋆ relation into the framework of only disc-specific quantities shows that a residual trend remains against disc stellar mass with equivalent slope and comparable scatter to that of the total galaxy relation. This suggests that the residual declining slope of the SFMS is intrinsic to the disc components of galaxies. We further investigate the distribution of bulge-to-total ratios (B/T) as a function of distance from the SFMS (ΔSFRMS). At all stellar masses, the average B/T of local galaxies decreases monotonically with increasing ΔSFRMS. Contrary to previous works, we find that the upper envelope of the SFMS is not dominated by objects with a significant bulge component. This rules out a scenario in which, in the local Universe, objects with increased star formation activity are simultaneously experiencing a significant bulge growth. We suggest that much of the discrepancies between different works studying the role of bulges originate from differences in the methodology of structurally decomposing galaxies.

scholarly journals The mass–metallicity and the fundamental metallicity relation revisited on a fully Te-based abundance scale for galaxies

2019 ◽  
Vol 491 (1) ◽  
pp. 944-964 ◽  
Author(s):  
Mirko Curti ◽  
Filippo Mannucci ◽  
Giovanni Cresci ◽  
Roberto Maiolino
Keyword(s):  
High Redshift ◽  
Formation Rate ◽  
Cosmic Time ◽  
Stellar Mass ◽  
Strong Line ◽  
High Redshift Galaxies ◽  
Star Forming ◽  
Theoretical Predictions ◽  
Galaxy Population ◽  
Good Agreement

ABSTRACT The relationships between stellar mass, gas-phase metallicity and star-formation rate (i.e. the mass–metallicity, MZR, and the fundamental metallicity relation, FMR) in the local Universe are revisited by fully anchoring the metallicity determination for SDSS galaxies on the Te abundance scale defined exploiting the strong-line metallicity calibrations presented by Curti et al. Self-consistent metallicity measurements allow a more unbiased assessment of the scaling relations involving M, Z and SFR, which provide powerful constraints for the chemical evolution models. We parametrize the MZR with a new functional form that allows us to better characterize the turnover mass. The slope and saturation metallicity are in good agreement with previous determinations of the MZR based on the Te method, while showing significantly lower normalization compared to those based on photoionization models. The Z–SFR dependence at fixed stellar mass is also investigated, being particularly evident for highly star-forming galaxies, where the scatter in metallicity is reduced up to a factor of ${\sim}30{{\ \rm per\ cent}}$. A new parametrization of the FMR is given by explicitly introducing the SFR dependence of the turnover mass into the MZR. The residual scatter in metallicity for the global galaxy population around the new FMR is 0.054 dex. The new FMR presented in this work represents a useful local benchmark to compare theoretical predictions and observational studies (of both local and high-redshift galaxies) whose metallicity measurements are tied to the abundance scale defined by the Te method, hence allowing proper assessment of its evolution with cosmic time.

scholarly journals SMOOTH(ER) STELLAR MASS MAPS IN CANDELS: CONSTRAINTS ON THE LONGEVITY OF CLUMPS IN HIGH-REDSHIFT STAR-FORMING GALAXIES

2012 ◽  
Vol 753 (2) ◽  
pp. 114 ◽  
Author(s):  
Stijn Wuyts ◽  
Natascha M. Förster Schreiber ◽  
Reinhard Genzel ◽  
Yicheng Guo ◽  
Guillermo Barro ◽  
...  
Keyword(s):  
High Redshift ◽  
Stellar Mass ◽  
Star Forming

scholarly journals The ISM scaling relations in DustPedia late-type galaxies: A benchmark study for the Local Universe

2020 ◽  
Vol 633 ◽  
pp. A100 ◽  
Author(s):  
V. Casasola ◽  
S. Bianchi ◽  
P. De Vis ◽  
L. Magrini ◽  
E. Corbelli ◽  
...  
Keyword(s):  
Gas Phase ◽  
Stellar Mass ◽  
Scaling Relations ◽  
Molecular Gas ◽  
Mass Ratio ◽  
Late Type ◽  
Local Universe ◽  
Dust Mass ◽  
Atomic Gas ◽  
Galaxy Morphology

Aims. The purpose of this work is the characterization of the main scaling relations between all of the interstellar medium (ISM) components, namely dust, atomic, molecular, and total gas, and gas-phase metallicity, as well as other galaxy properties, such as stellar mass (Mstar) and galaxy morphology, for late-type galaxies in the Local Universe. Methods. This study was performed by extracting late-type galaxies from the entire DustPedia sample and by exploiting the large and homogeneous dataset available thanks to the DustPedia project. The sample consists of 436 galaxies with morphological stage spanning from T = 1−10, Mstar from 6 × 107 to 3 × 1011 M⊙, star formation rate from 6 × 10−4 to 60 M⊙ yr−1, and oxygen abundance from 12 + log(O/H) = 8−9.5. Molecular and atomic gas data were collected from the literature and properly homogenized. All the masses involved in our analysis refer to the values within the optical disks of galaxies. The scaling relations involving the molecular gas are studied by assuming both a constant and a metallicity-dependent CO-to-H2 conversion factor (XCO). The analysis was performed by means of the survival analysis technique, in order to properly take into account the presence of both detection and nondetection in the data. Results. We confirm that the dust mass correlates very well with the total gas mass, and find –for the first time– that the dust mass correlates better with the atomic gas mass than with the molecular one. We characterize important mass ratios such as the gas fraction, the molecular-to-atomic gas mass ratio, the dust-to-total gas mass ratio (DGR), and the dust-to-stellar mass ratio, and study how they relate to each other, to galaxy morphology, and to gas-phase metallicity. Only the assumption of a metallicity-dependent XCO reproduces the expected decrease of the DGR with increasing morphological stage and decreasing gas-phase metallicity, with a slope of about 1. The DGR, the gas-phase metallicity, and the dust-to-stellar mass ratio are, for our galaxy sample, directly linked to galaxy morphology. The molecular-to-atomic gas mass ratio and the DGR show a positive correlation for low molecular gas fractions, but for galaxies rich in molecular gas this trend breaks down. To our knowledge, this trend has never been found before, and provides new constraints for theoretical models of galaxy evolution and a reference for high-redshift studies. We discuss several scenarios related to this finding. Conclusions. The DustPedia database of late-type galaxies is an extraordinary tool for the study of the ISM scaling relations, thanks to its homogeneous collection of data for the different ISM components. The database is made publicly available to the whole community.

scholarly journals Evolution of dwarf galaxy observable parameters

2020 ◽  
Vol 493 (1) ◽  
pp. 638-650
Author(s):  
Eimantas Ledinauskas ◽  
Kastytis Zubovas
Keyword(s):  
Galaxy Evolution ◽  
Dwarf Galaxies ◽  
Background Radiation ◽  
Dwarf Galaxy ◽  
High Redshift ◽  
Stellar Mass ◽  
Local Universe ◽  
Isolated Galaxies ◽  
Mass Assembly ◽  
Hubble Time

ABSTRACT We present a semi-analytic model of isolated dwarf galaxy evolution and use it to study the build-up of observed correlations between dwarf galaxy properties. We analyse the evolution using models with averaged and individual halo mass assembly histories in order to determine the importance of stochasticity on the present-day properties of dwarf galaxies. The model has a few free parameters, but when these are calibrated using the halo mass–stellar mass and stellar mass–metallicity relations, the results agree with other observed dwarf galaxy properties remarkably well. Redshift evolution shows that even isolated galaxies change significantly over the Hubble time and that ‘fossil dwarf galaxies’ with properties equivalent to those of high-redshift analogues should be extremely rare, or non-existent, in the local Universe. A break in most galaxy property correlations develops over time, at a stellar mass $M_* \simeq 10^7 \, {\rm M_{\odot }}$. It is caused predominantly by the ionizing background radiation and can therefore in principle be used to constrain the properties of reionization.

scholarly journals A contribution of star-forming clumps and accreting satellites to the mass assembly of z ∼ 2 galaxies

2019 ◽  
Vol 489 (2) ◽  
pp. 2792-2818 ◽  
Author(s):  
A Zanella ◽  
E Le Floc’h ◽  
C M Harrison ◽  
E Daddi ◽  
E Bernhard ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Stellar Mass ◽  
Mass Ratio ◽  
Star Forming ◽  
Spatially Resolved ◽  
The Galaxy ◽  
Mass Assembly

ABSTRACT We investigate the contribution of clumps and satellites to the galaxy mass assembly. We analysed spatially resolved HubbleSpace Telescope observations (imaging and slitless spectroscopy) of 53 star-forming galaxies at z ∼ 1–3. We created continuum and emission line maps and pinpointed residual ‘blobs’ detected after subtracting the galaxy disc. Those were separated into compact (unresolved) and extended (resolved) components. Extended components have sizes ∼2 kpc and comparable stellar mass and age as the galaxy discs, whereas the compact components are 1.5 dex less massive and 0.4 dex younger than the discs. Furthermore, the extended blobs are typically found at larger distances from the galaxy barycentre than the compact ones. Prompted by these observations and by the comparison with simulations, we suggest that compact blobs are in situ formed clumps, whereas the extended ones are accreting satellites. Clumps and satellites enclose, respectively, ∼20 per cent and ≲80 per cent of the galaxy stellar mass, ∼30 per cent and ∼20 per cent of its star formation rate. Considering the compact blobs, we statistically estimated that massive clumps (M⋆ ≳ 109 M⊙) have lifetimes of ∼650 Myr, and the less massive ones (108 < M⋆ < 109 M⊙) of ∼145 Myr. This supports simulations predicting long-lived clumps (lifetime ≳ 100 Myr). Finally, ≲30 per cent (13 per cent) of our sample galaxies are undergoing single (multiple) merger(s), they have a projected separation ≲10 kpc, and the typical mass ratio of our satellites is 1:5 (but ranges between 1:10 and 1:1), in agreement with literature results for close pair galaxies.

scholarly journals GOODS-Herschel: Dust attenuation up to z∼4

2012 ◽  
Vol 8 (S292) ◽  
pp. 289-289 ◽  
Author(s):  
M. Pannella ◽  
D. Elbaz ◽  
E. Daddi
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Line Emission ◽  
Stellar Mass ◽  
Massive Galaxies ◽  
Star Forming ◽  
Main Driver ◽  
Galaxy Sample ◽  
Stellar Masses ◽  
Dust Attenuation

AbstractWe quantitatively explore in a unbiased way the evolution of dust attenuation up to z ≈ 4 as a function of galaxy properties. We have used one of the deepest datasets available at present, in the GOODS-N field, to select a star forming galaxy sample and robustly measure galaxy redshifts, star formation rates, stellar masses and UV restframe properties. Our main results can be summarized as follows: i) we confirm that galaxy stellar mass is a main driver of UV dust attenuation in star forming galaxies: more massive galaxies are more dust attenuated than less massive ones; ii) strikingly, we find that the correlation does not evolve with redshift: the amount of dust attenuation is the same at all cosmic epochs for a fixed stellar mass; iii) this finding explains why and how the SFR–AUV relation evolves with redshift: the same amount of star formation is less attenuated at higher redshift because it is hosted in less massive galaxies; iv) combining our finding with results from line emission surveys, we confirm that line reddening is larger than continuum reddening, at least up to z ≈ 1.5; v) given the redshift evolution of the mass-metallicity relation, we predict that star forming galaxies at a fixed metal content are more attenuated at high redshift. Finally, we explored the correlation between UV dust attenuation and the spectral slope: vi) the correlation is evolving with redshift with star forming galaxies at lower redshift having redder spectra than higher redshift ones for the same amount of dust attenuation.

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