The effects of photoionization on galaxy formation - II. Satellite galaxies in the Local Group

ABSTRACT The nature of the dark matter can affect the collapse time of dark matter haloes, and can therefore be imprinted in observables such as the stellar population ages and star formation histories of dwarf galaxies. In this paper, we use high-resolution hydrodynamical simulations of Local Group-analogue (LG) volumes in cold dark matter (CDM), sterile neutrino warm dark matter (WDM) and self-interacting dark matter (SIDM) models with the eagle galaxy formation code to study how galaxy formation times change with dark matter model. We are able to identify the same haloes in different simulations, since they share the same initial density field phases. We find that the stellar mass of galaxies depends systematically on resolution, and can differ by as much as a factor of 2 in haloes of a given dark matter mass. The evolution of the stellar populations in SIDM is largely identical to that of CDM, but in WDM early star formation is instead suppressed. The time at which LG haloes can begin to form stars through atomic cooling is delayed by ∼200 Myr in WDM models compared to CDM. It will be necessary to measure stellar ages of old populations to a precision of better than 100 Myr, and to address degeneracies with the redshift of reionization – and potentially other baryonic processes – in order to use these observables to distinguish between dark matter models.

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The properties of satellite galaxies in simulations of galaxy formation

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2010.16690.x ◽

2010 ◽

Vol 406 (1) ◽

pp. 208-222 ◽

Cited By ~ 104

Author(s):

Takashi Okamoto ◽

Carlos S. Frenk ◽

Adrian Jenkins ◽

Tom Theuns

Keyword(s):

Galaxy Formation ◽

Satellite Galaxies

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The preferred direction of infalling satellite galaxies in the Local Group

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2010.17786.x ◽

2010 ◽

Vol 411 (3) ◽

pp. 1525-1535 ◽

Cited By ~ 76

Author(s):

Noam I. Libeskind ◽

Alexander Knebe ◽

Yehuda Hoffman ◽

Stefan Gottlöber ◽

Gustavo Yepes ◽

...

Keyword(s):

Local Group ◽

Preferred Direction ◽

Satellite Galaxies

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Phase-Space Correlations among Systems of Satellite Galaxies

Galaxies ◽

10.3390/galaxies9030066 ◽

2021 ◽

Vol 9 (3) ◽

pp. 66

Author(s):

Marcel S. Pawlowski

Keyword(s):

Phase Space ◽

Local Group ◽

Tangential Velocity ◽

Research Literature ◽

Highly Active ◽

Satellite Galaxy ◽

Different Types ◽

Motion Measurements ◽

Satellite Galaxies ◽

Observational Knowledge

Driven by the increasingly complete observational knowledge of systems of satellite galaxies, mutual spatial alignments and relations in velocities among satellites belonging to a common host have become a productive field of research. Numerous studies have investigated different types of such phase-space correlations and were met with varying degrees of attention by the community. The Planes of Satellite Galaxies issue is maybe the best-known example, with a rich field of research literature and an ongoing, controversial debate on how much of a challenge it poses to the ΛCDM model of cosmology. Another type of correlation, the apparent excess of close pairs of dwarf galaxies, has received considerably less attention despite its reported tension with ΛCDM expectations. With the fast expansion of proper motion measurements in recent years, largely driven by the Gaia mission, other peculiar phase-space correlations have been uncovered among the satellites of the Milky Way. Examples are the apparent tangential velocity excess of satellites compared to cosmological expectations, and the unexpected preference of satellites to be close to their pericenters. At the same time, other kinds of correlations have been found to be more in line with cosmological expectations—specifically, lopsided satellite galaxy systems and the accretion of groups of satellite galaxies. The latter has mostly been studied in cosmological simulations thus far, but it offers the potential to address some of the other issues by providing a way to produce correlations among the orbits of a group’s satellite galaxy members. This review is the first to provide an introduction to the highly active field of phase-space correlations among satellite galaxy systems. The emphasis is on summarizing existing, recent research and highlighting interdependencies between the different, currently almost exclusively individually considered types of correlations. Future prospects in light of upcoming observational facilities and our ever-expanding knowledge of satellite galaxy systems beyond the Local Group are also briefly discussed.

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Global H i asymmetries in IllustrisTNG: a diversity of physical processes disturb the cold gas in galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3200 ◽

2020 ◽

Vol 499 (4) ◽

pp. 5205-5219

Author(s):

Adam B Watts ◽

Chris Power ◽

Barbara Catinella ◽

Luca Cortese ◽

Adam R H Stevens

Keyword(s):

Galaxy Formation ◽

Atomic Hydrogen ◽

Physical Processes ◽

Low Velocity ◽

Ram Pressure ◽

Asymmetric Shape ◽

Satellite Galaxies ◽

Large Groups ◽

Disc Galaxies ◽

Cold Gas

ABSTRACT Observations of the cold neutral atomic hydrogen (H i) in and around disc galaxies have revealed that spatial and kinematic asymmetries are common place, and are reflected in the global H i spectra. We use the TNG100 box from the IllustrisTNG suite of cosmological simulations to study the conditions under which these asymmetries may arise in current theoretical galaxy formation models. We find that more than 50 per cent of the sample has at least a 10 per cent difference in integrated flux between the high- and low-velocity half of the spectrum, thus the typical TNG100 galaxy has an H i profile that is not fully symmetric. We find that satellite galaxies are a more asymmetric population than centrals, consistent with observational results. Using halo mass as a proxy for environment, this trend appears to be driven by the satellite population within the virial radius of haloes more massive than 1013 M⊙, typical of medium/large groups. We show that, while the excess of H i asymmetry in group satellites is likely driven by ram pressure, the bulk of the asymmetric H i profiles observed in TNG100 are driven by physical processes able to affect both the central and satellite populations. Our results highlight how asymmetries are not driven solely by environment, and multiple physical processes can produce the same asymmetric shape in global H i spectra.

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Extragalactic Globular Cluster Systems in the Near-IR

Symposium - International Astronomical Union ◽

10.1017/s0074180900223887 ◽

2002 ◽

Vol 207 ◽

pp. 294-300 ◽

Cited By ~ 1

Author(s):

Thomas H. Puzia ◽

Markus Kissler-Patig ◽

Jean Brodie ◽

Paul Goudfrooij ◽

Michael Hilker ◽

...

Keyword(s):

Galaxy Formation ◽

Globular Cluster ◽

Globular Clusters ◽

Local Group ◽

Optical Photometry ◽

Cluster Systems ◽

Near Ir ◽

Galaxy Formation And Evolution ◽

First Results ◽

Formation And Evolution

Extragalactic Globular Clusters are useful tracers of galaxy formation and evolution. Photometric studies of globular cluster systems beyond the Local Group are still the most popular method to investigate their physical properties, such as their ages and metallicities. However, the limitations of optical photometry are well known. The better wavelength sampling of the underlying cluster's SED using K-band photometry combined with optical passbands allows us to create colors which reduce the age-metallicity degeneracy to the largest extent. Here we report on the very first results of our near-IR photometric survey of globular cluster systems in early-type galaxies outside the Local Group.

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The shape alignment of satellite galaxies in Local Group-like pairs from the SDSS

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz285 ◽

2019 ◽

Vol 484 (3) ◽

pp. 4325-4336 ◽

Cited By ~ 2

Author(s):

Peng Wang ◽

Quan Guo ◽

Noam I Libeskind ◽

Elmo Tempel ◽

Chengliang Wei ◽

...

Keyword(s):

Local Group ◽

Shape Alignment ◽

Satellite Galaxies

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On the chemical evolution of the Milky Way

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308027841 ◽

2008 ◽

Vol 4 (S254) ◽

pp. 381-392 ◽

Cited By ~ 1

Author(s):

Nikos Prantzos

Keyword(s):

Chemical Evolution ◽

Galaxy Formation ◽

Milky Way ◽

Chemical Properties ◽

Solar Neighborhood ◽

Satellite Galaxies ◽

Metallicity Distribution

AbstractI discuss three different topics concerning the chemical evolution of the Milky Way (MW). 1) The metallicity distribution of the MW halo; it is shown that this distribution can be analytically derived in the framework of the hierarchical merging scenario for galaxy formation, assuming that the component sub-haloes had chemical properties similar to those of the progenitors of satellite galaxies of the MW. 2) The age-metallicity relationship (AMR) in the solar neighborhood; I argue for caution in deriving from data with important uncertainties (such as the age uncertainties in the Geneva-Copenhagen Survey) a relationship between average metallicity and age: derived relationships are shown to be systematically flatter than the true ones and should not be directly compared to models. 3) The radial mixing of stars in the disk, which may have important effects on various observables (scatter in AMR, extension of the tails of the metallicity distribution, flatenning of disk abundance profiles). Recent SPH + N-body simulations find considerable radial mixing, but only comparison to observations will ultimately determine the extent of that mixing.

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Hi and Galaxy Formation in Loose Groups

Publications of the Astronomical Society of Australia ◽

10.1071/as04055 ◽

2004 ◽

Vol 21 (4) ◽

pp. 390-392

Author(s):

Daniel J. Pisano

Keyword(s):

Dark Matter ◽

Galaxy Formation ◽

Local Group ◽

Dark Matter Halos ◽

Early Results ◽

Large Numbers ◽

The Galaxy ◽

Order Of Magnitude ◽

Low Mass ◽

High Velocity Clouds

AbstractModels of hierarchical galaxy formation predict that large numbers of low-mass, dark matter halos remain around galaxies today. These models predict an order of magnitude more halos than observed stellar satellites in the Local Group. One possible solution to this discrepancy is that the high-velocity clouds (HVCs) around the Milky Way may be associated with the excess dark matter halos and be the gaseous remnants of the galaxy formation process. If this is the case, then analogues to the HVCs should be visible in other groups. In this paper, I review the observations of Hi clouds lacking stars around other galaxies and in groups, present early results from our Hi survey of loose groups analogous to the Local Group, and discuss implications for the nature of HVCs and galaxy formation.

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SDSS-IV MaNGA: environmental dependence of gas metallicity gradients in local star-forming galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2218 ◽

2019 ◽

Vol 489 (1) ◽

pp. 1436-1450 ◽

Cited By ~ 4

Author(s):

Jianhui Lian ◽

Daniel Thomas ◽

Cheng Li ◽

Zheng Zheng ◽

Claudia Maraston ◽

...

Keyword(s):

Star Formation ◽

Galaxy Formation ◽

Cold Dark Matter ◽

Star Forming ◽

Spatially Resolved ◽

The Galaxy ◽

Low Mass ◽

Satellite Galaxies ◽

Galaxy Environment ◽

Gas Accretion

ABSTRACT Within the standard model of hierarchical galaxy formation in a Λ cold dark matter universe, the environment of galaxies is expected to play a key role in driving galaxy formation and evolution. In this paper, we investigate whether and how the gas metallicity and the star formation surface density (ΣSFR) depend on galaxy environment. To this end, we analyse a sample of 1162 local, star-forming galaxies from the galaxy survey Mapping Nearby Galaxies at APO (MaNGA). Generally, both parameters do not show any significant dependence on environment. However, in agreement with previous studies, we find that low-mass satellite galaxies are an exception to this rule. The gas metallicity in these objects increases while their ΣSFR decreases slightly with environmental density. The present analysis of MaNGA data allows us to extend this to spatially resolved properties. Our study reveals that the gas metallicity gradients of low-mass satellites flatten and their ΣSFR gradients steepen with increasing environmental density. By extensively exploring a chemical evolution model, we identify two scenarios that are able to explain this pattern: metal-enriched gas accretion or pristine gas inflow with varying accretion time-scales. The latter scenario better matches the observed ΣSFR gradients, and is therefore our preferred solution. In this model, a shorter gas accretion time-scale at larger radii is required. This suggests that ‘outside–in quenching’ governs the star formation processes of low-mass satellite galaxies in dense environments.

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