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 Two new free-floating or wide-orbit planets from microlensing

2019 ◽  
Vol 622 ◽  
pp. A201 ◽  
Author(s):  
Przemek Mróz ◽  
Andrzej Udalski ◽  
David P. Bennett ◽  
Yoon-Hyun Ryu ◽  
Takahiro Sumi ◽  
...  
Keyword(s):  
Gravitational Lensing ◽  
Milky Way ◽  
Planet Formation ◽  
Physical Mechanism ◽  
Galactic Disk ◽  
Galactic Bulge ◽  
Brown Dwarf ◽  
Low Mass ◽  
Rule Out

Planet formation theories predict the existence of free-floating planets that have been ejected from their parent systems. Although they emit little or no light, they can be detected during gravitational microlensing events. Microlensing events caused by rogue planets are characterized by very short timescales tE (typically below two days) and small angular Einstein radii θE (up to several μas). Here we present the discovery and characterization of two ultra-short microlensing events identified in data from the Optical Gravitational Lensing Experiment (OGLE) survey, which may have been caused by free-floating or wide-orbit planets. OGLE-2012-BLG-1323 is one of the shortest events discovered thus far (tE = 0.155 ± 0.005 d, θE = 2.37 ± 0.10μas) and was caused by an Earth-mass object in the Galactic disk or a Neptune-mass planet in the Galactic bulge. OGLE-2017-BLG-0560 (tE = 0.905 ± 0.005 d, θE = 38.7 ± 1.6μas) was caused by a Jupiter-mass planet in the Galactic disk or a brown dwarf in the bulge. We rule out stellar companions up to a distance of 6.0 and 3.9 au, respectively. We suggest that the lensing objects, whether located on very wide orbits or free-floating, may originate from the same physical mechanism. Although the sample of ultrashort microlensing events is small, these detections are consistent with low-mass wide-orbit or unbound planets being more common than stars in the Milky Way.

scholarly journals Ram Pressure Stripping of Spiral Galaxies in Clusters

2004 ◽  
Vol 217 ◽  
pp. 376-381
Author(s):  
Elke Schumacher ◽  
Gerhard Hensler
Keyword(s):  
Mass Loss ◽  
Spiral Galaxies ◽  
Disk Galaxies ◽  
Helmholtz Instability ◽  
Restoring Force ◽  
Ram Pressure ◽  
First Results ◽  
Two Phases ◽  
Gas Loss ◽  
Long Timescales

We investigate the process of ram pressure stripping by means of numerical simulations with a 2D hydrodynamical code. We present some first results of a set of simulations with varying galaxy velocities and ICM densities. We find that in typical cluster core environments disk galaxies lose a substantial amount of their gas, whereas in the outskirts of galaxy clusters the mass loss is quite small. Furthermore, the gas loss happens in two phases: In the initial phase gas is pushed out of regions where the ram pressure overcomes the gravitational restoring force; most of the overall gas loss happens in this phase. Afterwards the Kelvin-Helmholtz instability leads to a further mass loss at a small rate, that could be important on long timescales.

scholarly journals Nearest Neighbor: The Low-mass Milky Way Satellite Tucana III

2017 ◽  
Vol 838 (1) ◽  
pp. 11 ◽  
Author(s):  
J. D. Simon ◽  
T. S. Li ◽  
A. Drlica-Wagner ◽  
K. Bechtol ◽  
J. L. Marshall ◽  
...  
Keyword(s):  
Milky Way ◽  
Nearest Neighbor ◽  
Low Mass

scholarly journals Star formation in low-redshift cluster dwarf galaxies

2020 ◽  
Vol 493 (4) ◽  
pp. 5625-5635
Author(s):  
Cody M Rude ◽  
Madina R Sultanova ◽  
Gihan L Ipita Kaduwa Gamage ◽  
Wayne A Barkhouse ◽  
Sandanuwan P Kalawila Vithanage
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Sloan Digital Sky Survey ◽  
Galaxy Interactions ◽  
Cluster Data ◽  
Luminosity Functions ◽  
Sky Survey ◽  
Ram Pressure ◽  
Low Mass ◽  
Central Concentration

ABSTRACT Evolution of galaxies in dense environments can be affected by close encounters with neighbouring galaxies and interactions with the intracluster medium. Dwarf galaxies (dGs) are important as their low mass makes them more susceptible to these effects than giant systems. Combined luminosity functions (LFs) in the r and u band of 15 galaxy clusters were constructed using archival data from the Canada–France–Hawaii Telescope. LFs were measured as a function of clustercentric radius from stacked cluster data. Marginal evidence was found for an increase in the faint-end slope of the u-band LF relative to the r-band with increasing clustercentric radius. The dwarf-to-giant ratio (DGR) was found to increase toward the cluster outskirts, with the u-band DGR increasing faster with clustercentric radius compared to the r-band. The dG blue fraction was found to be ∼2 times larger than the giant galaxy blue fraction over all clustercentric distance (∼5σ level). The central concentration (C) was used as a proxy to distinguish nucleated versus non-nucleated dGs. The ratio of high-C to low-C dGs was found to be ∼2 times greater in the inner cluster region compared to the outskirts (2.8σ level). The faint-end slope of the r-band LF for the cluster outskirts (0.6 ≤ r/r200 < 1.0) is steeper than the Sloan Digital Sky Survey field LF, while the u-band LF is marginally steeper at the 2.5σ level. Decrease in the faint-end slope of the r- and u-band cluster LFs towards the cluster centre is consistent with quenching of star formation via ram pressure stripping and galaxy–galaxy interactions.

scholarly journals Complex distribution and velocity field of molecular gas in NGC 1316 as revealed by the Morita Array of ALMA

2019 ◽  
Vol 71 (4) ◽  
Author(s):  
Kana Morokuma-Matsui ◽  
Paolo Serra ◽  
Filippo M Maccagni ◽  
Bi-Qing For ◽  
Jing Wang ◽  
...  
Keyword(s):  
Velocity Field ◽  
Central Region ◽  
Milky Way ◽  
Conversion Factor ◽  
Rotating Disk ◽  
Molecular Gas ◽  
Dust Formation ◽  
Low Mass ◽  
First Time ◽  
Complex Distribution

Abstract We present the results of 12CO(J = 1–0) mosaicing observations of the cD galaxy NGC 1316 at kiloparsec resolution performed with the Morita Array of the Atacama Large Millimeter/submillimeter Array (ALMA). We reveal the detailed distribution of the molecular gas in the central region for the first time: a shell structure in the northwest, a barely resolved blob in the southeast of the center, and some clumps between them. The total molecular gas mass obtained with a standard Milky Way CO-to-H2 conversion factor is $(5.62 \pm 0.53) \times 10^{8}\, M_{\odot }$, which is consistent with previous studies. The disturbed velocity field of the molecular gas suggests that the molecular gas was injected very recently (<1 Gyr) if it has an external origin, and is in the process of settling into a rotating disk. Assuming that a low-mass gas-rich galaxy has accreted, the gas-to-dust ratio and H2-to-H i ratio are unusually low (∼28) and high (∼5.6), respectively. To explain these ratios additional processes should be taken into account, such as effective dust formation and conversion from atomic to molecular gas during the interaction. We also discuss the interaction between the nuclear jet and the molecular gas.

scholarly journals Cosmological simulations of the Milky Way

2009 ◽  
Vol 5 (H15) ◽  
pp. 193-193
Author(s):  
Lucio Mayer
Keyword(s):  
Milky Way ◽  
Cosmological Simulations ◽  
Low Mass

AbstractRecent simulations of forming low-mass galaxies suggests a strategy for obtaining realistic models of galaxies like the Milky-Way.

scholarly journals Ram-Pressure Induced Star Formation in the LMC

2008 ◽  
Vol 25 (3) ◽  
pp. 138-148 ◽  
Author(s):  
Chiara Mastropietro ◽  
Andreas Burkert ◽  
Ben Moore
Keyword(s):  
Star Formation ◽  
High Resolution ◽  
Milky Way ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Gaseous Disk ◽  
Star Formation Activity ◽  
Ram Pressure ◽  
Hydrodynamical Interaction

AbstractWe use high-resolution n-body/SPH simulations to study the hydrodynamical interaction between the Large Magellanic Cloud and the hot halo of the Milky Way. We investigate whether the ram-pressure acting on the gaseous disk of the satellite can explain the peculiarities observed in the Hidistribution and the location of the recent star formation activity.

scholarly journals Chemodynamical evolution of galaxies with hypernovae

2007 ◽  
Vol 3 (S245) ◽  
pp. 23-26
Author(s):  
Chiaki Kobayashi
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Formation Rate ◽  
Large Contribution ◽  
Milky Way Galaxy ◽  
Massive Galaxies ◽  
Evolution Of Galaxies ◽  
Low Mass ◽  
Formation And Evolution ◽  
The Difference

AbstractWe simulate the formation and evolution of galaxies with a hydrodynamical model including supernova and hypernova feedback. The large contribution of hypernovae is required from the observed abundance ratios in the Milky Way Galaxy. The hypernova feedback suppress star formation efficiently, which results in the cosmic star formation rate history peaked at z ~ 4. It also drives galactic outflows efficiently in low mass galaxies, and these winds eject heavy elements into the intergalactic medium. The ejected baryon and metal fraction is larger for less massive galaxies, which results in the mass-metallicity relation of galaxies. We also simulate the chemodynamical evolution of the Milky Way Galaxy, and show the difference of the stellar populations in the bulge and disk.

scholarly journals The nature and nurture of star clusters

2009 ◽  
Vol 5 (S266) ◽  
pp. 3-13 ◽  
Author(s):  
Bruce G. Elmegreen
Keyword(s):  
Globular Clusters ◽  
Dwarf Galaxy ◽  
Cluster Formation ◽  
Star Clusters ◽  
Mass Function ◽  
Radial Gradient ◽  
Cluster Mass ◽  
Low Mass ◽  
Nature And Nurture ◽  
Gas Loss

AbstractStar clusters have hierarchical patterns in space and time, suggesting formation processes in the densest regions of a turbulent interstellar medium. Clusters also have hierarchical substructure when they are young, which makes them all look like the inner mixed parts of a pervasive stellar hierarchy. Young field stars share this distribution, presumably because some of them came from dissolved clusters and others formed in a dispersed fashion in the same gas. The fraction of star formation that ends up in clusters is apparently not constant, but may increase with interstellar pressure. Hierarchical structure explains why stars form in clusters and why many of these clusters are self-bound. It also explains the cluster mass function. Halo globular clusters share many properties of disk clusters, including what appears to be an upper cluster cutoff mass. However, halo globulars are self-enriched and often connected with dwarf galaxy streams. The mass function of halo globulars could have initially been like the power-law mass function of disk clusters, but the halo globulars have lost their low-mass members. The reasons for this loss are not understood. It could have happened slowly over time as a result of cluster evaporation, or it could have happened early after cluster formation as a result of gas loss. The latter model explains best the observation that the globular cluster mass function has no radial gradient in galaxies.

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