The hydrodynamic evolution of the gas content in the dSph galaxy Ursa Minor induced by the feedback from types Ia and II supernovae

AbstractDwarf spheroidal galaxies of the Local Group share a similar characteristic nowadays: a low amount of gas in their interiors. In this work, we present results from a three-dimensional hydrodynamical simulation of the gas inside an object with similar characteristics of the Ursa Minor galaxy. We evolved the initial gas distribution over 3 Gyr, considering the effects of the types Ia and II supernovae. The instantaneous supernovae rates were derived from a chemical evolution model applied to spectroscopic data of the Ursa Minor galaxy. Our simulation shows that the amount of gas that is lost varies with time and galactocentric radius. The highest gas-loss rates occurred during the first 600 Myr of evolution. Our results also indicate that types Ia and II supernovae must be essential drivers of the gas loss in Ursa Minor galaxy (and probably in other similar dwarf galaxies).

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Pushing back the limits: detailed properties of dwarf galaxies in a ΛCDM universe

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832669 ◽

2018 ◽

Vol 616 ◽

pp. A96 ◽

Cited By ~ 26

Author(s):

Yves Revaz ◽

Pascale Jablonka

Keyword(s):

Star Formation ◽

Local Group ◽

Dwarf Galaxies ◽

Mass Scale ◽

Dwarf Spheroidal Galaxies ◽

The Galaxy ◽

Dynamical Simulations ◽

Ursa Minor ◽

Stellar Properties ◽

Star Formation Histories

We present the results of a set of high-resolution chemo-dynamical simulations of dwarf galaxies in a ΛCDM cosmology. Out of an original (3.4 Mpc/h)3 cosmological box, a sample of 27 systems are re-simulated from z = 70 to z = 0 using a zoom-in technique. Gas and stellar properties are confronted to the observations in the greatest details: in addition to the galaxy global properties, we investigated the model galaxy velocity dispersion profiles, half-light radii, star formation histories, stellar metallicity distributions, and [Mg/Fe] abundance ratios. The formation and sustainability of the metallicity gradients and kinematically distinct stellar populations are also tackled. We show how the properties of six Local Group dwarf galaxies, NGC 6622, Andromeda II, Sculptor, Sextans, Ursa Minor and Draco are reproduced, and how they pertain to three main galaxy build-up modes. Our results indicate that the interaction with a massive central galaxy could be needed for a handful of Local Group dwarf spheroidal galaxies only, the vast majority of the systems and their variety of star formation histories arising naturally from a ΛCDM framework. We find that models fitting well the local Group dwarf galaxies are embedded in dark haloes of mass between 5 × 108 to a few 109 M⊙, without any missing satellite problem. We confirm the failure of the abundance matching approach at the mass scale of dwarf galaxies. Some of the observed faint however gas-rich galaxies with residual star formation, such as Leo T and Leo P, remain challenging. They point out the need of a better understanding of the UV-background heating.

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The gas-loss evolution in dwarf spheroidal galaxies: Supernova feedback and environment effects in the case of the local group galaxy Ursa Minor

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320002161 ◽

2020 ◽

Vol 15 (S359) ◽

pp. 117-118

Author(s):

Anderson Caproni ◽

Gustavo Amaral Lanfranchi

Keyword(s):

Three Dimensional ◽

Hydrodynamic Simulations ◽

Dwarf Spheroidal Galaxies ◽

Environment Effects ◽

Ram Pressure ◽

The Galaxy ◽

Ursa Minor ◽

Gas Loss ◽

Ia Supernovae ◽

Supernova Feedback

AbstractIn this work, we performed two distinct non-cosmological, three-dimensional hydrodynamic simulations that evolved the gas component of a galaxy similar to the classical dwarf spheroidal galaxy Ursa Minor. Both simulations take into account types II and Ia supernovae feedback constrained by chemical evolution models, while ram-pressure stripping mechanism is added into one of them considering an intergalactic medium and a galactic velocity that resemble what is observed nowadays for the Ursa Minor galaxy. Our results show no difference in the amount of gas left inside the galaxy until 400 Myr of evolution. Moreover, the ram-pressure wind was stalled and inverted by thermal pressure of the interstellar medium and supernovae feedback during the same interval.

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Subaru Hyper Suprime-Cam Survey for the Local Group Dwarf Galaxies: Ursa Minor

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318006518 ◽

2018 ◽

Vol 14 (S344) ◽

pp. 94-95

Author(s):

Yutaka Komiyama

Keyword(s):

Binary Systems ◽

Main Sequence ◽

Local Group ◽

Dwarf Galaxies ◽

Structural Parameters ◽

Deep Imaging ◽

Ursa Minor ◽

Red Giant

AbstractWe have carried out a wide and deep imaging survey for the Local Group dwarf spheroidal galaxy Ursa Minor (UMi) using Hyper Suprime-Cam (HSC). The data cover out beyond the nominal tidal radius down to ~25 mag in i band, which is ~2 mag below the main sequence turn-off point. The structural parameters of UMi are derived using red giant branch (RGB) stars and sub-giant branch (SGB) stars, and the tidal radius is suggested to be larger than those estimated by the previous studies. It is also found that the distribution of bluer RGB/SGB stars is more extended than that of redder RGB/SGB stars. The fraction of binary systems is estimated to be ~0.4 from the morphology of the main sequences.

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Evidence for Light-weight Local Group Dwarf Spheroidal Galaxies

Symposium - International Astronomical Union ◽

10.1017/s0074180900183652 ◽

2004 ◽

Vol 220 ◽

pp. 365-366

Author(s):

J. R. Kuhn ◽

D. Kocevski

Keyword(s):

Dark Matter ◽

Milky Way ◽

Local Group ◽

Light Weight ◽

Natural Explanation ◽

Dwarf Spheroidal Galaxies ◽

Ursa Minor ◽

Matter Component ◽

Morphological State ◽

Spheroidal Galaxies

A simple and natural explanation for the dynamics and morphology of the Local Group Dwarf Spheroidal galaxies, Draco (Dra) and Ursa Minor (UMi), is that they are weakly unbound stellar systems with no significant dark matter component. A gentle, but persistent, Milky Way (MW) tide has left them in their current kinematic and morphological state (the “parametric tidal excitation”). A new test of a dark matter dominated dS potential follows from a careful observation of the “clumpiness” of the dS stellar surface density.

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Local Group Dwarf Galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318005835 ◽

2018 ◽

Vol 14 (S344) ◽

pp. 29-37

Author(s):

Andrew A. Cole

Keyword(s):

Star Formation ◽

Local Group ◽

Dwarf Galaxies ◽

Cosmic Time ◽

Star Formation History ◽

Gas Content ◽

Cosmological Context ◽

Low Mass ◽

Formation And Evolution ◽

Star Formation Histories

AbstractLocal Group dwarf galaxies are a unique astrophysical laboratory because they are the only objects in which we can reliably and precisely characterize the star formation histories of low-mass galaxies going back to the epoch of reionization. There are of order 100 known galaxies less massive than the Small Magellanic Cloud within ~1 Megaparsec of the Milky Way, with a vide variety of star formation history, gas content, and mass to light ratios. In this overview the current understanding of the formation and evolution of low-mass galaxies across cosmic time will be presented, and the possibility of drawing links between the properties of individual systems and the broader Local Group and cosmological context will be discussed. Local Group dwarfs will remain a uniquely powerful testbed to constrain the properties of dark matter and to evaluate the performance of simulations for the foreseeable future.

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THREE-DIMENSIONAL HYDRODYNAMICAL SIMULATIONS OF THE SUPERNOVAE-DRIVEN GAS LOSS IN THE DWARF SPHEROIDAL GALAXY URSA MINOR

The Astrophysical Journal ◽

10.1088/0004-637x/805/2/109 ◽

2015 ◽

Vol 805 (2) ◽

pp. 109 ◽

Cited By ~ 11

Author(s):

A. Caproni ◽

G. A. Lanfranchi ◽

A. Luiz da Silva ◽

D. Falceta-Gonçalves

Keyword(s):

Three Dimensional ◽

Ursa Minor ◽

Hydrodynamical Simulations ◽

Gas Loss

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Outskirts of Local Group Dwarf Galaxies Revealed by Subaru Hyper Suprime-Cam

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316009273 ◽

2016 ◽

Vol 11 (S321) ◽

pp. 25-27

Author(s):

Yutaka Komiyama

Keyword(s):

Stellar Population ◽

Local Group ◽

Dwarf Galaxies ◽

High Spatial Resolution ◽

Ccd Camera ◽

High Sensitivity ◽

Irregular Galaxy ◽

Ursa Minor ◽

Ngc 6822 ◽

Shed Light

AbstractLocal Group galaxies are important targets since their stellar populations can be resolved, and their properties can be investigated in detail with the help of stellar evolutionary models. The newly-built instrument for the 8.2m Subaru Telescope, Hyper Suprime-Cam (HSC), which has a 1 Giga pixel CCD camera with 1.5 degrees field of view, is the best instrument for observing Local Group galaxies. We have carried out a survey for Local Group dwarf galaxies using HSC aiming to shed light on the outskirts of these galaxies. The survey covers target galaxies out beyond the tidal radii down to a depth unexplored by previous surveys. Thanks to the high spatial resolution and high sensitivity provided by the Subaru Telescope, we are able to investigate properties such as spatial distribution and stellar population from the very center of galaxies to the outskirts. In this article, I will show results for the dwarf irregular galaxy NGC 6822 and the dwarf spheroidal galaxy Ursa Minor.

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A New Reservoir of Dwarf Galaxy Candidates in the Centaurus A Group

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318006634 ◽

2018 ◽

Vol 14 (S344) ◽

pp. 353-356

Author(s):

Matthew A. Taylor ◽

Paul Eigenthaler ◽

Thomas H. Puzia ◽

Roberto P. Muñoz ◽

Karen X. Ribbeck ◽

...

Keyword(s):

Local Group ◽

Dwarf Galaxies ◽

Dwarf Galaxy ◽

Elliptical Galaxy ◽

Large Reservoir ◽

Dwarf Spheroidal Galaxies ◽

Low Mass ◽

New Reservoir ◽

Centaurus A

AbstractWe have searched optical u′g′r′i′z′ imaging of 22 deg2 centred on the nearby giant elliptical galaxy NGC 5128 for new dwarf galaxies in the Centaurus A group. We report 45 promising new candidates, which are broadly consistent with the properties of nearby dwarf spheroidal galaxies and extend the size-luminosity relation toward fainter total luminosities and smaller sizes for known dwarf galaxies outside the Local Group (LG). Altogether, these new results show NGC 5128 to be the host of a large reservoir of low-mass dwarf galaxies that is at least as rich as that of the LG and is ripe for detailed follow-up observations.

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Dwarf Galaxies, Cold Dark Matter, and Biased Galaxy Formation

Symposium - International Astronomical Union ◽

10.1017/s0074180900150491 ◽

1987 ◽

Vol 117 ◽

pp. 362-362

Author(s):

Avishai Dekel ◽

Joseph Silk

Keyword(s):

Dark Matter ◽

Galaxy Formation ◽

Surface Brightness ◽

Cold Dark Matter ◽

Velocity Dispersion ◽

Local Group ◽

Dwarf Galaxies ◽

Virgo Cluster ◽

Slow Decrease ◽

Gas Loss

The formation of dwarf, diffuse, metal-poor galaxies, as a result of supernova driven winds, is reexamained in view of the accumulating data on dwarfs in the local group and in the Virgo cluster. The observed drop in both surface-brightness and metallicity with decreasing luminosity is not easily understood if the gaseous protogalaxies are self-gravitating (because they swell after gas-loss), but they are produced naturally inside dominant halos, with a mass-radius relation that indicates ‘cold’ dark matter. The theory predicts for the faint dwarfs an M/L that increases with decreasing luminosity up to 10–100, and a corresponding slow decrease in velocity dispersion down to 5–10 km/s.

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