scholarly journals Tracing the local volume galaxy halo‐to‐stellar mass ratio with satellite kinematics

2021 ◽  
Author(s):  
Igor Karachentsev ◽  
Olga Kashibadze
Keyword(s):  
Stellar Mass ◽  
Mass Ratio ◽  
Local Volume ◽  
Galaxy Halo

scholarly journals Dynamics of galaxy structures in the Local Volume

2014 ◽  
Vol 11 (S308) ◽  
pp. 173-180
Author(s):  
I. D. Karachentsev
Keyword(s):  
Milky Way ◽  
Local Density ◽  
Stellar Mass ◽  
Nearby Galaxy ◽  
Mass Ratio ◽  
Local Volume ◽  
Orbital Masses ◽  
The Galaxy ◽  
The Mean

AbstractI consider a sample of ‘Updated Nearby Galaxy Catalog’ that contains eight hundred objects within 11 Mpc. Environment of each galaxy is characterized by a tidal index Θ1 depending on separation and mass of the galaxy Main Disturber (=MD). The UNGC galaxies with a common MD are ascribed to its ‘suite’ and ranked according to their Θ1. Fifteen the most populated suites contain more than half of the UNGC sample. The fraction of MDs among the brightest galaxies is almost 100% and drops to 50% at M_B = -18 mag. The observational properties of galaxies accumulated in UNGC are used to derive orbital masses of giant galaxies via motions of their satellites. The average orbital-to-stellar mass ratio for them is MorbM* ≃ 30, corresponding to the mean local density of matter Ωm ≃ 0.09, i.e 1/3 of the global cosmic one. The dark-to-stellar mass ratio for the Milky Way and M31 is typical for other neighboring giant galaxies.

scholarly journals ‘Scraggy’ dark haloes around bulge-less spiral

2019 ◽  
Vol 486 (3) ◽  
pp. 3697-3701 ◽  
Author(s):  
I D Karachentsev ◽  
V E Karachentseva
Keyword(s):  
Total Mass ◽  
Spiral Galaxies ◽  
Stellar Mass ◽  
Low Density ◽  
Mean Square ◽  
Velocity Difference ◽  
Orbital Mass ◽  
Local Volume ◽  
The Mean ◽  
K Band

ABSTRACT We use a sample of 220 face-on bulge-less galaxies situated in the low-density environment to estimate their total mass via orbital motions of supposed rare satellites. Our inspection reveals 43 dwarf companions having the mean projected separation of 130 kpc and the mean-square velocity difference of 96 km s−1. For them, we obtain the mean orbital-mass-to-K-band luminosity ratio of 20 ± 3. Seven bulge-less spirals in the Local Volume are also characterized by the low mean ratio, Morb/LK = 22 ± 5. We conclude that bulge-less Sc–Scd–Sd galaxies have poor dark haloes, about two times lower than that of bulgy spiral galaxies of the same stellar mass.

scholarly journals The Connection Between Galaxies and Their Dark Matter Halos

2018 ◽  
Vol 56 (1) ◽  
pp. 435-487 ◽  
Author(s):  
Risa H. Wechsler ◽  
Jeremy L. Tinker
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Cosmic Time ◽  
Stellar Mass ◽  
Dark Matter Halo ◽  
Strong Function ◽  
Galaxy Surveys ◽  
Narrow Region ◽  
Open Questions ◽  
Galaxy Halo

In our modern understanding of galaxy formation, every galaxy forms within a dark matter halo. The formation and growth of galaxies over time is connected to the growth of the halos in which they form. The advent of large galaxy surveys as well as high-resolution cosmological simulations has provided a new window into the statistical relationship between galaxies and halos and its evolution. Here, we define this galaxy–halo connection as the multivariate distribution of galaxy and halo properties that can be derived from observations and simulations. This galaxy–halo connection provides a key test of physical galaxy-formation models; it also plays an essential role in constraints of cosmological models using galaxy surveys and in elucidating the properties of dark matter using galaxies. We review techniques for inferring the galaxy–halo connection and the insights that have arisen from these approaches. Some things we have learned are that galaxy-formation efficiency is a strong function of halo mass; at its peak in halos around a pivot halo mass of 1012M⊙, less than 20% of the available baryons have turned into stars by the present day; the intrinsic scatter in galaxy stellar mass is small, less than 0.2 dex at a given halo mass above this pivot mass; below this pivot mass galaxy stellar mass is a strong function of halo mass; the majority of stars over cosmic time were formed in a narrow region around this pivot mass. We also highlight key open questions about how galaxies and halos are connected, including understanding the correlations with secondary properties and the connection of these properties to galaxy clustering.

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 A systematic metallicity study of DustPedia galaxies reveals evolution in the dust-to-metal ratios

2019 ◽  
Vol 623 ◽  
pp. A5 ◽  
Author(s):  
P. De Vis ◽  
A. Jones ◽  
S. Viaene ◽  
V. Casasola ◽  
C. J. R. Clark ◽  
...  
Keyword(s):  
Star Formation ◽  
Grain Growth ◽  
Stellar Mass ◽  
Mass Ratio ◽  
Local Conditions ◽  
Metal Ratio ◽  
Stellar Masses ◽  
Dust Grain ◽  
Dust Grain Growth ◽  
Metal Ratios

Observations of evolution in the dust-to-metal ratio allow us to constrain the dominant dust processing mechanisms. In this work, we present a study of the dust-to-metal and dust-to-gas ratios in a sub-sample of ~500 DustPedia galaxies. Using literature and MUSE emission line fluxes, we derived gas-phase metallicities (oxygen abundances) for over 10 000 individual regions and determine characteristic metallicities for each galaxy. We study how the relative dust, gas, and metal contents of galaxies evolve by using metallicity and gas fraction as proxies for evolutionary state. The global oxygen abundance and nitrogen-to-oxygen ratio are found to increase monotonically as galaxies evolve. Additionally, unevolved galaxies (gas fraction >60%, metallicity 12 + log(O∕H) < 8.2) have dust-to-metal ratios that are about a factor of 2.1 lower (a factor of six lower for galaxies with gas fraction >80%) than the typical dust-to-metal ratio (Md∕MZ ~ 0.214) for more evolved sources. However, for high gas fractions, the scatter is larger due to larger observational uncertainties as well as a potential dependence of the dust grain growth timescale and supernova dust yield on local conditions and star formation histories. We find chemical evolution models with a strong contribution from dust grain growth describe these observations reasonably well. The dust-to-metal ratio is also found to be lower for low stellar masses and high specific star formation rates (with the exception of some sources undergoing a starburst). Finally, the metallicity gradient correlates weakly with the HI-to-stellar mass ratio, the effective radius and the dust-to-stellar mass ratio, but not with stellar mass.

scholarly journals Physical correlations of the scatter between galaxy mass, stellar content, and halo mass

2020 ◽  
Vol 493 (1) ◽  
pp. 337-350 ◽  
Author(s):  
Christopher Bradshaw ◽  
Alexie Leauthaud ◽  
Andrew Hearin ◽  
Song Huang ◽  
Peter Behroozi
Keyword(s):  
Dark Matter ◽  
Spectroscopic Data ◽  
Real Space ◽  
Stellar Mass ◽  
Dark Matter Halo ◽  
Potential Candidate ◽  
Stellar Content ◽  
Central Galaxy ◽  
Galaxy Halo ◽  
Physical Correlations

ABSTRACT We use the UniverseMachine to analyse the source of scatter between the central galaxy mass, the total stellar mass in the halo, and the dark matter halo mass, for massive (Mvir &gt; 1013 M⊙) haloes. We also propose a new halo mass estimator, the cen+N mass: the sum of the stellar mass of the central and the N most massive satellites. We show that, when real space positions are perfectly known, the cen+N mass has scatter competitive with that of richness-based estimators. However, in redshift space, using a simple cluster finder, the cen+N mass suffers less from projection effects in the UniverseMachine model. The cen+N mass is therefore a potential candidate to constrain cosmology with upcoming spectroscopic data from DESI. We analyse the scatter in stellar mass at fixed halo mass and show that the total stellar mass in a halo is uncorrelated with secondary halo properties, but that the central stellar mass is a function of both halo mass and halo age. This is because central galaxies in older haloes have had more time to grow via accretion. If the UniverseMachine model is correct, this implies that haloes selected using the centrals stellar mass will be biased old and that accurate galaxy-halo modelling of mass selected samples therefore needs to consider halo age in addition to mass.

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 Revealing the galaxy–halo connection in IllustrisTNG

2019 ◽  
Vol 490 (4) ◽  
pp. 5693-5711 ◽  
Author(s):  
Sownak Bose ◽  
Daniel J Eisenstein ◽  
Lars Hernquist ◽  
Annalisa Pillepich ◽  
Dylan Nelson ◽  
...  
Keyword(s):  
Strong Predictor ◽  
Stellar Mass ◽  
High Mass ◽  
Angular Momenta ◽  
Central Galaxy ◽  
Wide Range ◽  
The Galaxy ◽  
Best Fitting ◽  
Galaxy Halo ◽  
Satellite Galaxies

ABSTRACT We use the IllustrisTNG (TNG) simulations to explore the galaxy–halo connection as inferred from state-of-the-art cosmological, magnetohydrodynamical simulations. With the high-mass resolution and large volume achieved by combining the 100 Mpc (TNG100) and 300 Mpc (TNG300) volumes, we establish the mean occupancy of central and satellite galaxies and their dependence on the properties of the dark matter haloes hosting them. We derive best-fitting HOD parameters from TNG100 and TNG300 for target galaxy number densities of $\bar{n}_g = 0.032\,$  and $\bar{n}_g = 0.016\, h^3$ Mpc−3, respectively, corresponding to a minimum galaxy stellar mass of $M_\star \sim 1.9\times 10^9\, $ and $M_\star \sim 3.5\times 10^9\, {\rm M}_\odot$, respectively, in hosts more massive than $10^{11}\, {\rm M}_\odot$. Consistent with previous work, we find that haloes located in dense environments, with low concentrations, later formation times, and high angular momenta are richest in their satellite population. At low mass, highly concentrated haloes and those located in overdense regions are more likely to contain a central galaxy. The degree of environmental dependence is sensitive to the definition adopted for the physical boundary of the host halo. We examine the extent to which correlations between galaxy occupancy and halo properties are independent and demonstrate that HODs predicted by halo mass and present-day concentration capture the qualitative dependence on the remaining halo properties. At fixed halo mass, concentration is a strong predictor of the stellar mass of the central galaxy, which may play a defining role in the fate of the satellite population. The radial distribution of satellite galaxies, which exhibits a universal form across a wide range of host halo mass, is described accurately by the best-fitting NFW density profile of their host haloes.

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