scholarly journals The SAMI Galaxy Survey: The contribution of different kinematic classes to the stellar mass function of nearby galaxies

2019 ◽  
Author(s):  
Kexin Guo ◽  
Luca Cortese ◽  
Danail Obreschkow ◽  
Barbara Catinella ◽  
Jesse van de Sande ◽  
...  
Keyword(s):  
Mass Function ◽  
Stellar Mass ◽  
Stellar Kinematics ◽  
Local Universe ◽  
Mass Budget ◽  
Nearby Galaxies ◽  
Integral Field Spectrograph ◽  
Galaxy Population ◽  
Stellar Masses ◽  
Almost All

Abstract We use the complete Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey to determine the contribution of slow rotators, as well as different types of fast rotators, to the stellar mass function of galaxies in the local Universe. We use stellar kinematics not only to discriminate between fast and slow rotators, but also to distinguish between dynamically cold systems (i.e., consistent with intrinsic axis ratios<0.3) and systems including a prominent dispersion-supported bulge. We show that fast rotators account for more than $80\%$ of the stellar mass budget of nearby galaxies, confirming that their number density overwhelms that of slow rotators at almost all masses from 109 to 1011.5M⊙. Most importantly, dynamically cold disks contribute to at least $25\%$ of the stellar mass budget of the local Universe, significantly higher than what is estimated from visual morphology alone. For stellar masses up to 1010.5M⊙, this class makes up $>=30\%$ of the galaxy population in each stellar mass bin. The fact that many galaxies that are visually classified as having two-components have stellar spin consistent with dynamically cold disks suggests that the inner component is either rotationally-dominated (e.g., bar, pseudo-bulge) or has little effect on the global stellar kinematics of galaxies.

scholarly journals How robustly can we constrain the low-mass end of the z ∼ 6−7 stellar mass function? The limits of lensing models and stellar population assumptions in the Hubble Frontier Fields

2020 ◽  
Vol 501 (2) ◽  
pp. 1568-1590
Author(s):  
Lukas J Furtak ◽  
Hakim Atek ◽  
Matthew D Lehnert ◽  
Jacopo Chevallard ◽  
Stéphane Charlot
Keyword(s):  
Star Formation ◽  
Mass Function ◽  
Stellar Mass ◽  
Star Formation History ◽  
Space Telescope ◽  
Formation History ◽  
Low Mass ◽  
Stellar Masses ◽  
Dust Attenuation ◽  
The Impact

ABSTRACT We present new measurements of the very low mass end of the galaxy stellar mass function (GSMF) at z ∼ 6−7 computed from a rest-frame ultraviolet selected sample of dropout galaxies. These galaxies lie behind the six Hubble Frontier Field clusters and are all gravitationally magnified. Using deep Spitzer/IRAC and Hubble Space Telescope imaging, we derive stellar masses by fitting galaxy spectral energy distributions and explore the impact of different model assumptions and parameter degeneracies on the resulting GSMF. Our sample probes stellar masses down to $M_{\star }\gt 10^{6}\, \text{M}_{\odot}$ and we find the z ∼ 6−7 GSMF to be best parametrized by a modified Schechter function that allows for a turnover at very low masses. Using a Monte Carlo Markov chain analysis of the GSMF, including accurate treatment of lensing uncertainties, we obtain a relatively steep low-mass end slope $\alpha \simeq -1.96_{-0.08}^{+0.09}$ and a turnover at $\log (M_T/\text{M}_{\odot})\simeq 7.10_{-0.56}^{+0.17}$ with a curvature of $\beta \simeq 1.00_{-0.73}^{+0.87}$ for our minimum assumption model with constant star formation history (SFH) and low dust attenuation, AV ≤ 0.2. We find that the z ∼ 6−7 GSMF, in particular its very low mass end, is significantly affected by the assumed functional form of the star formation history and the degeneracy between stellar mass and dust attenuation. For example, the low-mass end slope ranges from $\alpha \simeq -1.82_{-0.07}^{+0.08}$ for an exponentially rising SFH to $\alpha \simeq -2.34_{-0.10}^{+0.11}$ when allowing AV of up to 3.25. Future observations at longer wavelengths and higher angular resolution with the James Webb Space Telescope are required to break these degeneracies and to robustly constrain the stellar mass of galaxies on the extreme low-mass end of the GSMF.

scholarly journals The Bimodality of Galaxy Populations Revisited Through Spectral Synthesis

2006 ◽  
Vol 2 (S235) ◽  
pp. 139-139
Author(s):  
L. Sodré ◽  
A. Mateus ◽  
R. Cid Fernandes ◽  
G. Stasińska ◽  
W. Schoenell ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Spectral Synthesis ◽  
Synthesis Method ◽  
Local Universe ◽  
Massive Galaxies ◽  
Star Forming ◽  
The Galaxy ◽  
Galaxy Populations ◽  
Galaxy Population ◽  
Stellar Masses

AbstractWe revisit the bimodality of the galaxy population seen in the local universe. We address this issue in terms of physical properties of galaxies, such as mean stellar ages and stellar masses, derived from the application of a spectral synthesis method to galaxy spectra from the SDSS. We show that the mean light-weighted stellar age of galaxies presents the best description of the bimodality seen in the galaxy population. The stellar mass has an additional role since most of the star-forming galaxies present in the local universe are low-mass galaxies. Our results give support to the existence of a ‘downsizing’ in galaxy formation, where nowadays massive galaxies tend to have stellar populations older than those found in less massive objects.

scholarly journals Correlations between H α equivalent width and galaxy properties at z = 0.47: Physical or selection-driven?

2021 ◽  
Vol 503 (4) ◽  
pp. 5115-5133
Author(s):  
A A Khostovan ◽  
S Malhotra ◽  
J E Rhoads ◽  
S Harish ◽  
C Jiang ◽  
...  
Keyword(s):  
Star Formation ◽  
Equivalent Width ◽  
Luminosity Function ◽  
Mass Function ◽  
Stellar Mass ◽  
High Mass ◽  
Selection Effects ◽  
Star Formation Activity ◽  
Low Mass ◽  
Stellar Masses

ABSTRACT The H α equivalent width (EW) is an observational proxy for specific star formation rate (sSFR) and a tracer of episodic, bursty star-formation activity. Previous assessments show that the H α EW strongly anticorrelates with stellar mass as M−0.25 similar to the sSFR – stellar mass relation. However, such a correlation could be driven or even formed by selection effects. In this study, we investigate how H α EW distributions correlate with physical properties of galaxies and how selection biases could alter such correlations using a z = 0.47 narrow-band-selected sample of 1572 H α emitters from the Ly α Galaxies in the Epoch of Reionization (LAGER) survey as our observational case study. The sample covers a 3 deg2 area of COSMOS with a survey comoving volume of 1.1 × 105 Mpc3. We assume an intrinsic EW distribution to form mock samples of H α emitters and propagate the selection criteria to match observations, giving us control on how selection biases can affect the underlying results. We find that H α EW intrinsically correlates with stellar mass as W0∝M−0.16 ± 0.03 and decreases by a factor of ∼3 from 107 M⊙ to 1010 M⊙, while not correcting for selection effects steepens the correlation as M−0.25 ± 0.04. We find low-mass H α emitters to be ∼320 times more likely to have rest-frame EW&gt;200 Å compared to high-mass H α emitters. Combining the intrinsic W0–stellar mass correlation with an observed stellar mass function correctly reproduces the observed H α luminosity function, while not correcting for selection effects underestimates the number of bright emitters. This suggests that the W0–stellar mass correlation when corrected for selection effects is physically significant and reproduces three statistical distributions of galaxy populations (line luminosity function, stellar mass function, EW distribution). At lower stellar masses, we find there are more high-EW outliers compared to high stellar masses, even after we take into account selection effects. Our results suggest that high sSFR outliers indicative of bursty star formation activity are intrinsically more prevalent in low-mass H α emitters and not a byproduct of selection effects.

scholarly journals Comparing the host galaxies of different type supernovae

2015 ◽  
Vol 11 (S319) ◽  
pp. 139-139
Author(s):  
Y. C. Liang ◽  
X. Shao ◽  
M. Dennefeld ◽  
X. Y. Chen ◽  
L. Zhou ◽  
...  
Keyword(s):  
Stellar Mass ◽  
Significant Fraction ◽  
Host Galaxies ◽  
Global Properties ◽  
Different Types ◽  
Type Ia ◽  
Total Light ◽  
Stellar Masses ◽  
Almost All ◽  
Cross Matching

AbstractWe compare the host galaxies of 902 supernovae, including Type Ia, II and Ibc, which are selected by cross-matching the Asiago Supernova Catalog with the SDSS DR7. We further selected 213 galaxies by requiring the light fraction of spectral observations > 15%, which could represent well the global properties of the galaxies. The diagrams related to Dn(4000), HδA, stellar masses, SFRs and specific SFRs for the SNe hosts show that almost all SNe II and most of SNe Ibc occur in SF galaxies. A significant fraction of SNe Ia occurs in AGNs and Absorp galaxies. These results are compared with those of the 689 comparison galaxies where the SDSS fiber captures < 15% of the total light. These comparison galaxies appear biased towards higher 12+log(O/H) (~0.1dex) at a given stellar mass, suggesting the aperture effect should be kept in mind when the properties of the hosts for different types of SNe are discussed.

scholarly journals The XXL Survey

2018 ◽  
Vol 620 ◽  
pp. A7 ◽  
Author(s):  
V. Guglielmo ◽  
B. M. Poggianti ◽  
B. Vulcani ◽  
C. Adami ◽  
F. Gastaldello ◽  
...  
Keyword(s):  
Mass Function ◽  
Stellar Mass ◽  
X Ray ◽  
Field Versus ◽  
Final Sample ◽  
Wide Range ◽  
The Galaxy ◽  
Halo Masses ◽  
Stellar Masses ◽  
Physical Phenomena

Context. The fraction of galaxies bound in groups in the nearby Universe is high (50% at z ~ 0). Systematic studies of galaxy properties in groups are important in order to improve our understanding of the evolution of galaxies and of the physical phenomena occurring within this environment. Aims. We have built a complete spectrophotometric sample of galaxies within X-ray detected, optically spectroscopically confirmed groups and clusters (G&C), covering a wide range of halo masses at z ≤ 0.6. Methods. In the context of the XXL survey, we analyse a sample of 164 G&C in the XXL-North region (XXL-N), at z ≤ 0.6, with a wide range of virial masses (1.24 × 1013 ≤ M500,scal(M⊙) ≤ 6.63 × 1014) and X-ray luminosities ((2.27 × 1041 ≤ L500,scalXXL(erg s−1) ≤ 2.15 × 1044)). The G&C are X-ray selected and spectroscopically confirmed. We describe the membership assignment and the spectroscopic completeness analysis, and compute stellar masses. As a first scientific exploitation of the sample, we study the dependence of the galaxy stellar mass function (GSMF) on global environment. Results. We present a spectrophotometric characterisation of the G&C and their galaxies. The final sample contains 132 G&C, 22 111 field galaxies and 2225 G&C galaxies with r-band magnitude <20. Of the G&C, 95% have at least three spectroscopic members, and 70% at least ten. The shape of the GSMF seems not to depend on environment (field versus G&C) or X-ray luminosity (used as a proxy for the virial mass of the system). These results are confirmed by the study of the correlation between mean stellar mass of G&C members and L500,scalXXL. We release the spectrophotometric catalogue of galaxies with all the quantities computed in this work. Conclusions. As a first homogeneous census of galaxies within X-ray spectroscopically confirmed G&C at these redshifts, this sample will allow environmental studies of the evolution of galaxy properties.

scholarly journals Milky Way analogues in MaNGA: multiparameter homogeneity and comparison to the Milky Way

2019 ◽  
Vol 491 (3) ◽  
pp. 3672-3701 ◽  
Author(s):  
N Boardman ◽  
G Zasowski ◽  
A Seth ◽  
J Newman ◽  
B Andrews ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Milky Way ◽  
Central Star ◽  
Stellar Kinematics ◽  
Star Forming ◽  
Wide Range ◽  
The Galaxy ◽  
Central Regions ◽  
Galaxy Population ◽  
Stellar Masses

ABSTRACT The Milky Way provides an ideal laboratory to test our understanding of galaxy evolution, owing to our ability to observe our Galaxy over fine scales. However, connecting the Galaxy to the wider galaxy population remains difficult, due to the challenges posed by our internal perspective and to the different observational techniques employed. Here, we present a sample of galaxies identified as Milky Way analogues on the basis of their stellar masses and bulge-to-total ratios, observed as part of the Mapping Nearby Galaxies at Apache Point Observatory survey. We analyse the galaxies in terms of their stellar kinematics and populations as well as their ionized gas contents. We find our sample to contain generally young stellar populations in their outskirts. However, we find a wide range of stellar ages in their central regions, and we detect central active galactic nucleus-like or composite-like activity in roughly half of the sample galaxies, with the other half consisting of galaxies with central star-forming emission or emission consistent with old stars. We measure gradients in gas metallicity and stellar metallicity that are generally flatter in physical units than those measured for the Milky Way; however, we find far better agreement with the Milky Way when scaling gradients by galaxies’ disc scale lengths. From this, we argue much of the discrepancy in metallicity gradients to be due to the relative compactness of the Milky Way, with differences in observing perspective also likely to be a factor.

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 Can magnetized turbulence set the mass scale of stars?

2020 ◽  
Vol 496 (4) ◽  
pp. 5072-5088 ◽  
Author(s):  
Dávid Guszejnov ◽  
Michael Y Grudić ◽  
Philip F Hopkins ◽  
Stella S R Offner ◽  
Claude-André Faucher-Giguère
Keyword(s):  
Star Formation ◽  
Scaling Laws ◽  
Initial Conditions ◽  
Mass Function ◽  
Stellar Mass ◽  
Mass Scale ◽  
Initial Mass Function ◽  
Mhd Turbulence ◽  
Numerical Resolution ◽  
Stellar Masses

ABSTRACT Understanding the evolution of self-gravitating, isothermal, magnetized gas is crucial for star formation, as these physical processes have been postulated to set the initial mass function (IMF). We present a suite of isothermal magnetohydrodynamic (MHD) simulations using the gizmo code that follow the formation of individual stars in giant molecular clouds (GMCs), spanning a range of Mach numbers found in observed GMCs ($\mathcal {M} \sim 10\!-\!50$). As in past works, the mean and median stellar masses are sensitive to numerical resolution, because they are sensitive to low-mass stars that contribute a vanishing fraction of the overall stellar mass. The mass-weighted median stellar mass M50 becomes insensitive to resolution once turbulent fragmentation is well resolved. Without imposing Larson-like scaling laws, our simulations find $M_\mathrm{50} \,\, \buildrel\propto \over \sim \,\,M_\mathrm{0} \mathcal {M}^{-3} \alpha _\mathrm{turb}\, \mathrm{SFE}^{1/3}$ for GMC mass M0, sonic Mach number $\mathcal {M}$, virial parameter αturb, and star formation efficiency SFE = M⋆/M0. This fit agrees well with previous IMF results from the ramses, orion2, and sphng codes. Although M50 has no significant dependence on the magnetic field strength at the cloud scale, MHD is necessary to prevent a fragmentation cascade that results in non-convergent stellar masses. For initial conditions and SFE similar to star-forming GMCs in our Galaxy, we predict M50 to be $\gt 20 \, \mathrm{M}_{\odot }$, an order of magnitude larger than observed ($\sim 2 \, \mathrm{M}_\odot$), together with an excess of brown dwarfs. Moreover, M50 is sensitive to initial cloud properties and evolves strongly in time within a given cloud, predicting much larger IMF variations than are observationally allowed. We conclude that physics beyond MHD turbulence and gravity are necessary ingredients for the IMF.

scholarly journals What drives the velocity dispersion of ionized gas in star-forming galaxies?

2019 ◽  
Vol 486 (4) ◽  
pp. 4463-4472 ◽  
Author(s):  
Xiaoling Yu ◽  
Yong Shi ◽  
Yanmei Chen ◽  
David R Law ◽  
Dmitry Bizyaev ◽  
...  
Keyword(s):  
Star Formation ◽  
Velocity Dispersion ◽  
Gravitational Instability ◽  
Theoretical Models ◽  
Stellar Mass ◽  
Ionized Gas ◽  
Star Forming ◽  
Energy Feedback ◽  
Nearby Galaxies ◽  
Stellar Masses

Abstract We analyse the intrinsic velocity dispersion properties of 648 star-forming galaxies observed by the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, to explore the relation of intrinsic gas velocity dispersions with star formation rates (SFRs), SFR surface densities ($\rm {\Sigma _{SFR}}$), stellar masses, and stellar mass surface densities ($\rm {\Sigma _{*}}$). By combining with high z galaxies, we found that there is a good correlation between the velocity dispersion and the SFR as well as $\rm {\Sigma _{SFR}}$. But the correlation between the velocity dispersion and the stellar mass as well as $\rm {\Sigma _{*}}$ is moderate. By comparing our results with predictions of theoretical models, we found that the energy feedback from star formation processes alone and the gravitational instability alone cannot fully explain simultaneously the observed velocity–dispersion/SFR and velocity–dispersion/$\rm {\Sigma _{SFR}}$ relationships.

scholarly journals Adaptive optics imaging of Lyman break galaxies as progenitors of spheroids in the local Universe

2007 ◽  
Vol 3 (S245) ◽  
pp. 447-450
Author(s):  
M. Akiyama ◽  
Y. Minowa ◽  
N. Kobayashi ◽  
K. Ohta ◽  
I. Iwata
Keyword(s):  
Adaptive Optics ◽  
Spatial Clustering ◽  
Stellar Mass ◽  
Disk Galaxies ◽  
Local Universe ◽  
Lyman Break Galaxies ◽  
Optical Images ◽  
Major Merger ◽  
Nearby Galaxies ◽  
Red Galaxies

AbstractIn order to reveal the stellar mass distribution of z ~ 3 galaxies, we are conducting deep imaging observations of U-dropout Lyman Break Galaxies (LBGs) with Adaptive Optics (AO) systems in K-band, which corresponds to rest-frame V-band of z ~ 3 galaxies. The results of the Subaru intensive-program observations with AO36/NGS/IRCS indicate that 1) the K-band peaks of some of the LBGs brighter than K = 22.0 mag show significant offset from those in the optical images, 2) the z ~ 3 $M_{V}^{*}$ LBGs and serendipitously observed Distant Red Galaxies (DRGs) have flat profiles similar to disk galaxies in the local universe (i.e., Sérsic with n < 2), and 3) the surface stellar mass densities of the $M_{V}^{*}$ LBGs are 3-6 times larger than those of disk galaxies at z = 0 − 1. Considering the lack of n > 2 systems among the luminous z ~ 3 LBGs and DRGs, and their strong spatial clustering, we infer that the dense n < 2 disk-like structures evolve into the n > 2 spheroids of nearby galaxies through relaxations due to major merger events.

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