scholarly journals The cumulative star formation histories of dwarf galaxies with TNG50. I: environment-driven diversity and connection to quenching

2021 ◽  
Vol 508 (2) ◽  
pp. 1652-1674 ◽  
Author(s):  
Gandhali D Joshi ◽  
Annalisa Pillepich ◽  
Dylan Nelson ◽  
Elad Zinger ◽  
Federico Marinacci ◽  
...  
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Control Sample ◽  
Stellar Mass ◽  
Key Factors ◽  
Star Forming ◽  
Theoretical Predictions ◽  
Mass Assembly ◽  
Star Formation Histories ◽  
Vast Range

ABSTRACT We present the cumulative star formation histories (SFHs) of >15 000 dwarf galaxies ($M_{\rm *}=10^{7-10}\, {\rm M}_{\odot }$) simulated with the TNG50 run of the IllustrisTNG suite across a vast range of environments. The key factors that determine the dwarfs’ SFHs are their central/satellite status and stellar mass, with centrals and more massive dwarfs assembling their stellar mass at later times, on average, compared to satellites and lower mass dwarfs. Satellites (in hosts of mass $M_{\rm 200c, host}=10^{12-14.3}\, {\rm M}_{\odot }$) assembled 90 per cent of their stellar mass ${\sim}7.0_{-5.5}^{+3.3}$ Gyr ago, on average and within the 10th to 90th percentiles, while the centrals did so only ${\sim}1.0_{-0.5}^{+4.0}$ Gyr ago. TNG50 predicts a large diversity in SFHs, so that individual dwarfs can have significantly different cumulative SFHs compared to the stacked median SFHs. Satellite dwarfs with the highest stellar mass to host cluster mass ratios have the latest stellar mass assembly. Conversely, satellites at fixed stellar and host halo mass found closer to the cluster centre or accreted at earlier times show significantly earlier stellar mass assembly. These trends and the shapes of the SFHs themselves are a manifestation of the varying proportions within a given subsample of quenched versus star-forming galaxies, which exhibit markedly distinct SFH shapes. Finally, satellite dwarfs in the most massive hosts have higher SFRs at early times, well before accretion into their z = 0 host, compared to a control sample of centrals mass-matched at the time of accretion. This is the result of the satellites being preprocessed in smaller hosts prior to accretion. Our findings are useful theoretical predictions for comparison to future resolved stellar population observations.

scholarly journals The role of mergers and interactions in driving the evolution of dwarf galaxies over cosmic time

2020 ◽  
Vol 500 (4) ◽  
pp. 4937-4957 ◽  
Author(s):  
G Martin ◽  
R A Jackson ◽  
S Kaviraj ◽  
H Choi ◽  
J E G Devriendt ◽  
...  
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Large Fraction ◽  
Structural Evolution ◽  
Cosmic Time ◽  
Stellar Mass ◽  
High Mass ◽  
Key Drivers ◽  
Mass Assembly

ABSTRACT Dwarf galaxies (M⋆ < 109 M⊙) are key drivers of mass assembly in high-mass galaxies, but relatively little is understood about the assembly of dwarf galaxies themselves. Using the NewHorizon cosmological simulation (∼40 pc spatial resolution), we investigate how mergers and fly-bys drive the mass assembly and structural evolution of around 1000 field and group dwarfs up to z = 0.5. We find that, while dwarf galaxies often exhibit disturbed morphologies (5 and 20 per cent are disturbed at z = 1 and z = 3 respectively), only a small proportion of the morphological disturbances seen in dwarf galaxies are driven by mergers at any redshift (for 109 M⊙, mergers drive under 20 per cent morphological disturbances). They are instead primarily the result of interactions that do not end in a merger (e.g. fly-bys). Given the large fraction of apparently morphologically disturbed dwarf galaxies which are not, in fact, merging, this finding is particularly important to future studies identifying dwarf mergers and post-mergers morphologically at intermediate and high redshifts. Dwarfs typically undergo one major and one minor merger between z = 5 and z = 0.5, accounting for 10 per cent of their total stellar mass. Mergers can also drive moderate star formation enhancements at lower redshifts (3 or 4 times at z = 1), but this accounts for only a few per cent of stellar mass in the dwarf regime given their infrequency. Non-merger interactions drive significantly smaller star formation enhancements (around two times), but their preponderance relative to mergers means they account for around 10 per cent of stellar mass formed in the dwarf regime.

scholarly journals Galaxy And Mass Assembly (GAMA): linking star formation histories and stellar mass growth

2013 ◽  
Vol 434 (1) ◽  
pp. 209-221 ◽  
Author(s):  
Amanda E. Bauer ◽  
Andrew M. Hopkins ◽  
Madusha Gunawardhana ◽  
Edward N. Taylor ◽  
Ivan Baldry ◽  
...  
Keyword(s):  
Star Formation ◽  
Stellar Mass ◽  
Mass Growth ◽  
Mass Assembly ◽  
Star Formation Histories

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 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 A spatially resolved map of the kinematics, star formation and stellar mass assembly in a star-forming galaxy atz= 4.9

2009 ◽  
Vol 400 (3) ◽  
pp. 1121-1131 ◽  
Author(s):  
A. M. Swinbank ◽  
T. M. Webb ◽  
J. Richard ◽  
R. G. Bower ◽  
R. S. Ellis ◽  
...  
Keyword(s):  
Star Formation ◽  
Stellar Mass ◽  
Star Forming ◽  
Spatially Resolved ◽  
Mass Assembly

scholarly journals Galaxy and Mass Assembly (GAMA): The environmental dependence of the galaxy main sequence

2018 ◽  
Vol 618 ◽  
pp. A1 ◽  
Author(s):  
L. Wang ◽  
P. Norberg ◽  
S. Brough ◽  
M. J. I. Brown ◽  
E. da Cunha ◽  
...  
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Spectral Energy Distribution ◽  
Stellar Mass ◽  
Dark Matter Halo ◽  
Spectral Energy ◽  
Star Forming ◽  
The Galaxy ◽  
Mass Assembly ◽  
Environmental Dependence

Aims: We aim to investigate if the environment (characterised by the host dark matter halo mass) plays any role in shaping the galaxy star formation main sequence (MS). Methods: The Galaxy and Mass Assembly project (GAMA) combines a spectroscopic survey with photometric information in 21 bands from the far-ultraviolet (FUV) to the far-infrared (FIR). Stellar masses and dust-corrected star-formation rates (SFR) are derived from spectral energy distribution (SED) modelling using MAGPHYS. We use the GAMA galaxy group catalogue to examine the variation of the fraction of star-forming galaxies (SFG) and properties of the MS with respect to the environment. Results: We examine the environmental dependence for stellar mass selected samples without preselecting star-forming galaxies and study any dependence on the host halo mass separately for centrals and satellites out to z ∼ 0.3. We find the SFR distribution at fixed stellar mass can be described by the combination of two Gaussians (referred to as the star-forming Gaussian and the quiescent Gaussian). Using the observed bimodality to define SFG, we investigate how the fraction of SFG F(SFG) and properties of the MS change with environment. For centrals, the position of the MS is similar to the field but with a larger scatter. No significant dependence on halo mass is observed. For satellites, the position of the MS is almost always lower (by ∼0.2 dex) compared to the field and the width is almost always larger. F(SFG) is similar between centrals (in different halo mass bins) and field galaxies. However, for satellites F(SFG) decreases with increasing halo mass and this dependence is stronger towards lower redshift.

scholarly journals Star Formation in CALIFA survey perturbed galaxies. II. Star Formation Histories and Oxygen Abundances

2021 ◽  
Author(s):  
A Morales-Vargas ◽  
J P Torres-Papaqui ◽  
F F Rosales-Ortega ◽  
M Chow-Martínez ◽  
J J Trejo-Alonso ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Mass Density ◽  
Stellar Mass ◽  
Mass Rate ◽  
Star Forming ◽  
Star Forming Regions ◽  
Stellar Feedback ◽  
Tidal Interactions ◽  
Mass Assembly

Abstract Galaxy evolution is generally affected by tidal interactions. Firstly, in this series, we reported several effects which suggest that tidal interactions contribute to regulating star formation (SF). To confirm that so, we now compare stellar mass assembly histories and SF look-back time annular profiles between CALIFA survey tidally and non-tidally perturbed galaxies. We pair their respective star-forming regions at the closest stellar mass surface densities to reduce the influence of stellar mass. The assembly histories and annular profiles show statistically significant differences so that higher star formation rates characterize regions in tidally perturbed galaxies. These regions underwent a more intense (re)activation of SF in the last 1 Gyr. Varying shapes of the annular profiles also reflect fluctuations between suppression and (re)activation of SF. Since gas-phase abundances use to be lower in more actively than in less actively star-forming galaxies, we further explore the plausible presence of metal-poor gas inflows able to dilute such abundances. The resolved relations of oxygen (O) abundance, with stellar mass density and with total gas fraction, show slightly lower O abundances for regions in tidally perturbed galaxies. The single distributions of O abundances statistically validate that so. Moreover, from a metallicity model based on stellar feedback, the mass rate differentials (inflows−outflows) show statistically valid higher values for regions in tidally perturbed galaxies. These differentials, and the metal fractions from the population synthesis, suggest dominant gas inflows in these galaxies. This dominance, and the differences in SF through time, confirm the previously reported effects of tidal interactions on SF.

scholarly journals Scaling relations and baryonic cycling in local star-forming galaxies

2020 ◽  
Vol 643 ◽  
pp. A180
Author(s):  
L. K. Hunt ◽  
C. Tortora ◽  
M. Ginolfi ◽  
R. Schneider
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Dwarf Galaxies ◽  
Formation Rate ◽  
Gas Content ◽  
Scaling Relations ◽  
Star Forming ◽  
Atomic Gas ◽  
Mass Assembly ◽  
Gas Accretion

Assessments of the cold-gas reservoir in galaxies are a cornerstone for understanding star-formation processes and the role of feedback and baryonic cycling in galaxy evolution. Here we exploit a sample of 392 galaxies (dubbed MAGMA, Metallicity and Gas for Mass Assembly), presented in a recent paper, to quantify molecular and atomic gas properties across a broad range in stellar mass, Mstar, from ∼107 − 1011 M⊙. First, we find the metallicity (Z) dependence of the conversion factor for CO luminosity to molecular H2 mass αCO to be shallower than previous estimates, with αCO  ∝  (Z/Z⊙)−1.55. Second, molecular gas mass MH2 is found to be strongly correlated with Mstar and star-formation rate (SFR), enabling predictions of MH2 good to within ∼0.2 dex; analogous relations for atomic gas mass MHI and total gas mass Mgas are less accurate, ∼0.4 dex and ∼0.3 dex, respectively. Indeed, the behavior of atomic gas mass MHI in MAGMA scaling relations suggests that it may be a third, independent variable that encapsulates information about the circumgalactic environment and gas accretion. If Mgas is considered to depend on MHI, together with Mstar and SFR, we obtain a relation that predicts Mgas to within ∼0.05 dex. Finally, the analysis of depletion times and the scaling of MHI/Mstar and MH2/Mstar over three different mass bins suggests that the partition of gas and the regulation of star formation through gas content depends on the mass regime. Dwarf galaxies (Mstar  ≲  3 × 109 M⊙) tend to be overwhelmed by (H I) accretion, and despite short τH2 (and thus presumably high star-formation efficiency), star formation is unable to keep up with the gas supply. For galaxies in the intermediate Mstar “gas-equilibrium” bin (3 × 109 M⊙ ≲ Mstar ≲3 × 1010 M⊙), star formation proceeds apace with gas availability, and H I and H2 are both proportional to SFR. In the most massive “gas-poor, bimodality” regime (Mstar ≳ 3 × 1010 M⊙), H I does not apparently participate in star formation, although it generally dominates in mass over H2. Our results confirm that atomic gas plays a key role in baryonic cycling, and is a fundamental ingredient for current and future star formation, especially in dwarf galaxies.

scholarly journals Star formation histories of dwarf galaxies in the FIRE simulations: dependence on mass and Local Group environment

2019 ◽  
Vol 489 (4) ◽  
pp. 4574-4588 ◽  
Author(s):  
Shea Garrison-Kimmel ◽  
Andrew Wetzel ◽  
Philip F Hopkins ◽  
Robyn Sanderson ◽  
Kareem El-Badry ◽  
...  
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Near Field ◽  
Stellar Mass ◽  
Group Environment ◽  
Zoom In ◽  
The Individual ◽  
Star Formation Histories

ABSTRACT We study star formation histories (SFHs) of 500 dwarf galaxies (stellar mass $M_\ast =10^5\!-\!10^9\, \rm {M}_\odot$) from FIRE-2 cosmological zoom-in simulations. We compare dwarfs around individual Milky Way (MW)-mass galaxies, dwarfs in Local Group (LG)-like environments, and true field (i.e. isolated) dwarf galaxies. We reproduce observed trends wherein higher mass dwarfs quench later (if at all), regardless of environment. We also identify differences between the environments, both in terms of ‘satellite versus central’ and ‘LG versus individual MW versus isolated dwarf central.’ Around the individual MW-mass hosts, we recover the result expected from environmental quenching: central galaxies in the ‘near field’ have more extended SFHs than their satellite counterparts, with the former more closely resemble isolated (true field) dwarfs (though near-field centrals are still somewhat earlier forming). However, this difference is muted in the LG-like environments, where both near-field centrals and satellites have similar SFHs, which resemble satellites of single MW-mass hosts. This distinction is strongest for M* = 106–$10^7\, \rm {M}_\odot$ but exists at other masses. Our results suggest that the paired halo nature of the LG may regulate star formation in dwarf galaxies even beyond the virial radii of the MW and Andromeda. Caution is needed when comparing zoom-in simulations targeting isolated dwarf galaxies against observed dwarf galaxies in the LG.

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