scholarly journals Gaseous Halos of Simulated Milky Way-like Galaxies

2022 ◽  
Vol 6 (1) ◽  
pp. 16
Author(s):  
Bhavya Pardasani ◽  
Andrew Wetzel ◽  
Jenna Samuel
Keyword(s):  
Power Law ◽  
Milky Way ◽  
Host Galaxy ◽  
Gas Density ◽  
Ram Pressure ◽  
Galaxy Disk ◽  
Satellite Galaxies

Abstract In order to investigate the role of the host halo in quenching satellite galaxies, we have characterized a single Milky Way-like host galaxy from the FIRE simulations from z = 0–1.76 by quantifying the gas density of the host halo environment with respect to distance from the host and galactocentric latitude. The gas density decreases with increasing distance from the host according to a broken power law. At earlier times (2–10 Gyr ago), the density in the inner regions of the host halo was enhanced relative to z = 0. Thus, earlier infalling satellites experienced more ram-pressure and were more efficiently quenched compared to later infalling satellites. We also find that in the inner halo (<150 kpc) the density is 2–3 times larger close to the plane of the host galaxy disk versus above or below the disk, so satellites that orbit at low galactocentric latitudes may be more efficiently quenched.

scholarly journals Role of Magnetic Fields in Ram Pressure Stripped Galaxies

Galaxies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 116
Author(s):  
Ancla Müller ◽  
Alessandro Ignesti ◽  
Bianca Poggianti ◽  
Alessia Moretti ◽  
Mpati Ramatsoku ◽  
...  
Keyword(s):  
Magnetized Plasma ◽  
Stellar Disk ◽  
Cluster Galaxies ◽  
Gas Phases ◽  
Ram Pressure ◽  
The Galaxy ◽  
Galaxy Disk ◽  
Multi Wavelength ◽  
Multi Phase

Ram-pressure stripping is a crucial evolutionary driver for cluster galaxies and jellyfish galaxies characterized by very extended tails of stripped gas, and they are the most striking examples of it in action. Recently, those extended tails are found to show ongoing star formation, raising the question of how the stripped, cold gas can survive long enough to form new stars outside the stellar disk. In this study, we summarize the most recent results achieved within the GASP collaboration to provide a holistic explanation for this phenomenon. We focus on two textbook examples of jellyfish galaxies, JO206 and JW100, for which, via multi-wavelength observations from radio to X-ray and numerical simulations, we have explored the different gas phases (neutral, molecular, diffuse-ionized, and hot). Based on additional multi-phase gas studies, we now propose a scenario of stripped tail evolution including all phases that are driven by a magnetic draping sheath, where the intracluster turbulent magnetized plasma condenses onto the galaxy disk and tail and produces a magnetized interface that protects the stripped galaxy tail gas from evaporation. In such a scenario, the accreted environmental plasma can cool down and eventually join the tail gas, hence providing additional gas to form stars. The implications of our findings can shed light on the more general scenario of draping, condensation, and cooling of hot gas surrounding cold clouds that is fundamental in many astrophysical phenomena.

scholarly journals Satellite dwarf galaxies: stripped but not quenched

2019 ◽  
Vol 624 ◽  
pp. A11 ◽  
Author(s):  
Loic Hausammann ◽  
Yves Revaz ◽  
Pascale Jablonka
Keyword(s):  
Milky Way ◽  
Dwarf Galaxies ◽  
Direct Consequence ◽  
Host Galaxy ◽  
Star Forming ◽  
Tidal Forces ◽  
Ram Pressure ◽  
Halo Gas ◽  
The Impact ◽  
Cold Gas

In the Local Group, quenched gas-poor dwarfs galaxies are most often found close to the Milky Way and Andromeda, while star forming gas-rich ones are located at greater distances. This so-called morphology-density relation is often interpreted as the consequence of the ram pressure stripping of the satellites during their interaction with the Milky Way hot halo gas. While this process has been often investigated, self-consistent high resolution simulations were still missing. In this study, we have analysed the impact of both the ram pressure and tidal forces induced by a host galaxy on dwarf models as realistic as possible emerging from cosmological simulations. These models were re-simulated using both a wind tunnel and a moving box technique. The secular mass growth of the central host galaxy, as well as the gas density and temperature profiles of its hot halo have been taken into account. We show that while ram pressure is very efficient at stripping the hot and diffuse gas of the dwarf galaxies, it can remove their cold gas (T <  103 K) only in very specific conditions. Depending on the infall time of the satellites relatively to the build-up stage of the massive host, star formation can thus be prolonged instead of being quenched. This is the direct consequence of the clumpy nature of the cold gas and the thermal pressure the hot gas exerts onto it. We discuss the possibility that the variety in satellite populations among Milky Way-like galaxies reflects their accretion histories.

scholarly journals Quenching and ram pressure stripping of simulated Milky Way satellite galaxies

2018 ◽  
Vol 478 (1) ◽  
pp. 548-567 ◽  
Author(s):  
Christine M Simpson ◽  
Robert J J Grand ◽  
Facundo A Gómez ◽  
Federico Marinacci ◽  
Rüdiger Pakmor ◽  
...  
Keyword(s):  
Milky Way ◽  
Ram Pressure ◽  
Satellite Galaxies

scholarly journals The role of faint population III supernovae in forming CEMP stars in ultra-faint dwarf galaxies

2021 ◽  
Author(s):  
Myoungwon Jeon ◽  
Volker Bromm ◽  
Gurtina Besla ◽  
Jinmi Yoon ◽  
Yumi Choi
Keyword(s):  
Milky Way ◽  
Dwarf Galaxies ◽  
Mass Resolution ◽  
Explosion Energy ◽  
High Carbon ◽  
Cosmological Simulations ◽  
Carbon Abundance ◽  
The Absolute ◽  
Zoom In

Abstract CEMP-no stars, a subset of carbon enhanced metal poor (CEMP) stars ($\rm [C/Fe]\ge 0.7$ and $\rm [Fe/H]\lesssim -1$) have been discovered in ultra-faint dwarf (UFD) galaxies, with Mvir ≈ 108 M⊙ and M* ≈ 103 − 104 M⊙ at z = 0, as well as in the halo of the Milky Way (MW). These CEMP-no stars are local fossils that may reflect the properties of the first (Pop III) and second (Pop II) generation of stars. However, cosmological simulations have struggled to reproduce the observed level of carbon enhancement of the known CEMP-no stars. Here we present new cosmological hydrodynamic zoom-in simulations of isolated UFDs that achieve a gas mass resolution of mgas ≈ 60 M⊙. We include enrichment from Pop III faint supernovae (SNe), with ESN = 0.6 × 1051 erg, to understand the origin of CEMP-no stars. We confirm that Pop III and Pop II stars are mainly responsible for the formation of CEMP and C-normal stars respectively. New to this study, we find that a majority of CEMP-no stars in the observed UFDs and the MW halo can be explained by Pop III SNe with normal explosion energy (ESN = 1.2 × 1051 erg) and Pop II enrichment, but faint SNe might also be needed to produce CEMP-no stars with $\rm [C/Fe]\gtrsim 2$, corresponding to the absolute carbon abundance of $\rm A(C)\gtrsim 6.0$. Furthermore, we find that while we create CEMP-no stars with high carbon ratio $\rm [C/Fe]\approx 3-4$, by adopting faint SNe, it is still challenging to reproduce CEMP-no stars with extreme level of carbon abundance of $\rm A(C)\approx 7.0-7.5$, observed both in the MW halo and UFDs.

Quasar host galaxies and environments in the GAMA survey

2019 ◽  
Vol 15 (S356) ◽  
pp. 170-170
Author(s):  
Jari Kotilainen
Keyword(s):  
Galaxy Evolution ◽  
Large Scale ◽  
Group Membership ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Cluster Group ◽  
First Results ◽  
Triggering Mechanisms ◽  
Mass Assembly

AbstractWe present first results from our study of the host galaxies and environments of quasars in Galaxy And Mass Assembly (GAMA), a multiwavelength photometric and spectroscopic survey for ∼300,000 galaxies over ∼300 deg2, to a limiting magnitude of r ∼ 20 mag. We use a GAIA-selected sample of ∼350 quasars at z < 0.3 in GAMA. For all the quasars, we determine all surrounding GAMA galaxies and measure their star formation (SF) rate and SF history, and the host galaxy morphology and group membership of the quasars. As a comparison sample of inactive galaxies, we use 1000 subsets of galaxies in GAMA, matched in redshift and galaxy stellar mass to the quasars. We find that quasar activity does not depend on the large-scale environment (cluster/group/void), although quasars tend to prefer satellite location in their environment. Compared to inactive galaxies, quasars are preferentially hosted in bulge-dominated galaxies and have higher SF rates, both overall and averaged over the last 10 and 100 Myr. Quasars also have shorter median SF timescales, shorter median time since the last SF burst, and higher metallicity than inactive galaxies. We discuss these results in terms of triggering mechanisms of the quasar activity and the role of quasars in galaxy evolution.

scholarly journals The accreted nuclear clusters of the Milky Way

2020 ◽  
Vol 500 (2) ◽  
pp. 2514-2524
Author(s):  
Joel Pfeffer ◽  
Carmela Lardo ◽  
Nate Bastian ◽  
Sara Saracino ◽  
Sebastian Kamann
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Star Clusters ◽  
Host Galaxy ◽  
The Galaxy ◽  
Nuclear Clusters ◽  
The Common ◽  
Massive Clusters ◽  
Peculiar Case

ABSTRACT A number of the massive clusters in the halo, bulge, and disc of the Galaxy are not genuine globular clusters (GCs) but instead are different beasts altogether. They are the remnant nuclear star clusters (NSCs) of ancient galaxies since accreted by the Milky Way. While some clusters are readily identifiable as NSCs and can be readily traced back to their host galaxy (e.g. M54 and the Sagittarius Dwarf galaxy), others have proven more elusive. Here, we combine a number of independent constraints, focusing on their internal abundances and overall kinematics, to find NSCs accreted by the Galaxy and trace them to their accretion event. We find that the true NSCs accreted by the Galaxy are: M54 from the Sagittarius Dwarf, ω Centari from Gaia-Enceladus/Sausage, NGC 6273 from Kraken, and (potentially) NGC 6934 from the Helmi Streams. These NSCs are prime candidates for searches of intermediate-mass black holes (BHs) within star clusters, given the common occurrence of galaxies hosting both NSCs and central massive BHs. No NSC appears to be associated with Sequoia or other minor accretion events. Other claimed NSCs are shown not to be such. We also discuss the peculiar case of Terzan 5, which may represent a unique case of a cluster–cluster merger.

scholarly journals Are ultra-diffuse galaxies Milky Way-sized?

2020 ◽  
Vol 633 ◽  
pp. L3 ◽  
Author(s):  
Nushkia Chamba ◽  
Ignacio Trujillo ◽  
Johan H. Knapen
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Size Range ◽  
Mass Density ◽  
Effective Radius ◽  
Density Profiles ◽  
Gas Density ◽  
Undesirable Consequence ◽  
Definition Of ◽  
Density Threshold

Now almost 70 years since its introduction, the effective or half-light radius has become a very popular choice for characterising galaxy size. However, the effective radius measures the concentration of light within galaxies and thus does not capture our intuitive definition of size which is related to the edge or boundary of objects. For this reason, we aim to demonstrate the undesirable consequence of using the effective radius to draw conclusions about the nature of faint ultra-diffuse galaxies (UDGs) when compared to dwarfs and Milky Way-like galaxies. Instead of the effective radius, we use a measure of galaxy size based on the location of the gas density threshold required for star formation. Compared to the effective radius, this physically motivated definition places the sizes much closer to the boundary of a galaxy. Therefore, considering the sizes and stellar mass density profiles of UDGs and regular dwarfs, we find that the UDGs have sizes that are within the size range of dwarfs. We also show that currently known UDGs do not have sizes comparable to Milky Way-like objects. We find that, on average, UDGs are ten times smaller in extension than Milky Way-like galaxies. These results show that the use of size estimators sensitive to the concentration of light can lead to misleading results.

scholarly journals GAS LOSS BY RAM PRESSURE STRIPPING AND INTERNAL FEEDBACK FROM LOW-MASS MILKY WAY SATELLITES

2016 ◽  
Vol 826 (2) ◽  
pp. 148 ◽  
Author(s):  
Andrew Emerick ◽  
Mordecai-Mark Mac Low ◽  
Jana Grcevich ◽  
Andrea Gatto
Keyword(s):  
Milky Way ◽  
Internal Feedback ◽  
Ram Pressure ◽  
Low Mass ◽  
Gas Loss

scholarly journals A comparative study of satellite galaxies in Milky Way-like galaxies from HSC, DECaLS, and SDSS

2020 ◽  
Vol 500 (3) ◽  
pp. 3776-3801
Author(s):  
Wenting Wang ◽  
Masahiro Takada ◽  
Xiangchong Li ◽  
Scott G Carlsten ◽  
Ting-Wen Lan ◽  
...  
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Statistical Study ◽  
Satellite System ◽  
Large Scatter ◽  
Local Universe ◽  
Good Representative ◽  
Luminosity Functions ◽  
Satellite Galaxies ◽  
Good Agreement

ABSTRACT We conduct a comprehensive and statistical study of the luminosity functions (LFs) for satellite galaxies, by counting photometric galaxies from HSC, DECaLS, and SDSS around isolated central galaxies (ICGs) and paired galaxies from the SDSS/DR7 spectroscopic sample. Results of different surveys show very good agreement. The satellite LFs can be measured down to MV ∼ −10, and for central primary galaxies as small as 8.5 &lt; log10M*/M⊙ &lt; 9.2 and 9.2 &lt; log10M*/M⊙ &lt; 9.9, which implies there are on average 3–8 satellites with MV &lt; −10 around LMC-mass ICGs. The bright end cutoff of satellite LFs and the satellite abundance are both sensitive to the magnitude gap between the primary and its companions, indicating galaxy systems with larger magnitude gaps are on average hosted by less massive dark matter haloes. By selecting primaries with stellar mass similar to our Milky Way (MW), we discovered that (i) the averaged satellite LFs of ICGs with different magnitude gaps to their companions and of galaxy pairs with different colour or colour combinations all show steeper slopes than the MW satellite LF; (ii) there are on average more satellites with −15 &lt; MV &lt; −10 than those in our MW; (iii) there are on average 1.5 to 2.5 satellites with MV &lt; −16 around ICGs, consistent with our MW; (iv) even after accounting for the large scatter predicted by numerical simulations, the MW satellite LF is uncommon at MV &gt; −12. Hence, the MW and its satellite system are statistically atypical of our sample of MW-mass systems. In consequence, our MW is not a good representative of other MW-mass galaxies. Strong cosmological implications based on only MW satellites await additional discoveries of fainter satellites in extra-galactic systems. Interestingly, the MW satellite LF is typical among other MW-mass systems within 40 Mpc in the local Universe, perhaps implying the Local Volume is an underdense region.

Sign in / Sign up

Export Citation Format

Share Document