scholarly journals A mass threshold for galactic gas discs by spin flips

2020 ◽  
Vol 493 (3) ◽  
pp. 4126-4142 ◽  
Author(s):  
Avishai Dekel ◽  
Omri Ginzburg ◽  
Fangzhou Jiang ◽  
Jonathan Freundlich ◽  
Sharon Lapiner ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Critical Mass ◽  
Stellar Mass ◽  
Mass Dependence ◽  
Mass Ratio ◽  
High Angular Momentum ◽  
Merger Rate ◽  
Spin Flips ◽  
Supernova Feedback ◽  
Gas Supply

ABSTRACT We predict, analytically and by simulations, that gas discs tend to survive only in haloes above a threshold mass ∼2 × 1011 M⊙ (stellar mass ∼109 M⊙), with only a weak redshift dependence. At lower masses, the disc spins typically flip in less than an orbital time due to mergers associated with a change in the pattern of the feeding cosmic-web streams. This threshold arises from the halo merger rate when accounting for the mass dependence of the ratio of galactic baryons and halo mass. Above the threshold, wet compactions lead to massive central nuggets that allow the longevity of extended clumpy gas rings. Supernova feedback has a major role in disrupting discs below the critical mass, by driving the stellar-to-halo mass ratio that affects the merger rate, by stirring up turbulence and suppressing high-angular-momentum gas supply, and by confining major compactions to the critical mass. Our predictions seem consistent with current observed fractions of gas discs, to be explored by future observations that will resolve galaxies below 109 M⊙ at high redshifts, e.g. by JWST.

scholarly journals Criterion for Dynamical Instability of Mass Transfer in Binary Evolution

2002 ◽  
Vol 187 ◽  
pp. 297-302
Author(s):  
Zhanwen Han ◽  
Philipp Podsiadlowski ◽  
Christopher A. Tout
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Binary Systems ◽  
Main Sequence ◽  
Critical Mass ◽  
Dynamical Instability ◽  
Mass Ratio ◽  
The Core ◽  
Binary Evolution ◽  
Red Giant

AbstractUsing Eggleton’s code, we performed a series of binary evolution calculations in order to investigate the criterion for dynamical instability of mass transfer in binaries. In these calculations, we took the donor’s mass on the zero-age main sequence (ZAMS) from 0.8 to 1.9 M⊙. For each mass, we systematically varied the mass of the core at the beginning of mass transfer and the mass of the companion star. We assumed that mass transfer was completely non-conservative and that all the mass that was lost from the system carried with it the orbital angular momentum of the accreting component. We found that the critical mass ratio, above which mass transfer is dynamically unstable, is from 1.1 to 1.3 in these red-giant binary systems.

scholarly journals Halo-model Analysis of the Clustering of Photometric Luminous Red Galaxies at 0.10 ≤ z ≤1.05 from the Subaru Hyper Suprime-Cam Survey

2021 ◽  
Vol 922 (1) ◽  
pp. 23
Author(s):  
Shogo Ishikawa ◽  
Teppei Okumura ◽  
Masamune Oguri ◽  
Sheng-Chieh Lin
Keyword(s):  
Large Fraction ◽  
Critical Mass ◽  
Stellar Mass ◽  
Distribution Analysis ◽  
Dark Halo ◽  
Mass Dependence ◽  
Luminous Red Galaxies ◽  
Order Of Magnitude ◽  
Stellar Masses ◽  
Red Galaxies

Abstract We present the clustering analysis of photometric luminous red galaxies (LRGs) at a redshift range of 0.1 ≤ z ≤ 1.05 using 615,317 photometric LRGs selected from the Hyper Suprime-Cam Subaru Strategic Program, covering ∼124 deg2. Our sample covers a broad range of stellar masses and photometric redshifts and enables a halo occupation distribution analysis to study the redshift and stellar-mass dependence of dark halo properties of LRGs. We find a tight correlation between the characteristic dark halo mass to host central LRGs, M min , and the number density of LRGs, independently of redshifts, indicating that the formation of LRGs is associated with the global environment. The M min of LRGs depends only weakly on the stellar mass M ⋆ at M ⋆ ≲ 1010.75 h −2 M ⊙ at 0.3 < z < 1.05, in contrast to the case for all photometrically selected galaxies, for which M min shows significant dependence on M ⋆ even at low M ⋆. The weak stellar-mass dependence is indicative of the dark halo mass being the key parameter for the formation of LRGs, rather than the stellar mass. Our result suggests that the halo mass of ∼1012.5±0.2 h −1 M ⊙ is the critical mass for an efficient halo quenching due to the halo environment. We compare our result with the result of the hydrodynamical simulation to find that low-mass LRGs at z ∼ 1 will increase their stellar masses by an order of magnitude from z = 1 to 0 through mergers and satellite accretions, and that a large fraction of massive LRGs at z < 0.9 consist of LRGs that recently migrated from massive green valley galaxies or those that evolved from less massive LRGs through mergers and satellite accretions.

scholarly journals Origin of star-forming rings around massive centres in massive galaxies at z < 4

2020 ◽  
Vol 496 (4) ◽  
pp. 5372-5398 ◽  
Author(s):  
Avishai Dekel ◽  
Sharon Lapiner ◽  
Omri Ginzburg ◽  
Jonathan Freundlich ◽  
Fangzhou Jiang ◽  
...  
Keyword(s):  
Star Formation ◽  
Spiral Structure ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Mass Ratio ◽  
Central Mass ◽  
Massive Galaxies ◽  
Star Forming ◽  
Spin Flips ◽  
Supernova Feedback

ABSTRACT Using analytic modelling and simulations, we address the origin of an abundance of star-forming clumpy extended gas rings about massive central bodies in massive galaxies at z &lt; 4. Rings form by high-angular-momentum streams and survive in galaxies of Mstar &gt; 109.5–10 M⊙ where merger-driven spin flips and supernova feedback are ineffective. The rings survive after events of compaction to central nuggets. Ring longevity was unexpected based on inward mass transport driven by torques from violent disc instability. However, evaluating the torques from a tightly wound spiral structure, we find that the time-scale for transport per orbital time is long and $\propto \! \delta _{\rm d}^{-3}$, with δd the cold-to-total mass ratio interior to the ring. A long-lived ring forms when the ring transport is slower than its replenishment by accretion and the interior depletion by star formation rate, both valid for δd &lt; 0.3. The central mass that lowers δd is a compaction-driven bulge and/or dark matter, aided by the lower gas fraction at z &lt; 4, provided that it is not too low. The ring is Toomre unstable for clump and star formation. The high-z dynamic rings are not likely to arise form secular resonances or collisions. Active galactic nucleus feedback is not expected to affect the rings. Mock images of simulated rings through dust indicate qualitative consistency with observed rings about bulges in massive z ∼ 0.5–3 galaxies, in H α and deep HST imaging. ALMA mock images indicate that z ∼ 0.5–1 rings should be detectable. We quote expected observable properties of rings and their central nuggets.

scholarly journals Emerge: Empirical predictions of galaxy merger rates since z ∼ 6

2020 ◽  
Author(s):  
Joseph A O’Leary ◽  
Benjamin P Moster ◽  
Thorsten Naab ◽  
Rachel S Somerville
Keyword(s):  
Galaxy Formation ◽  
Power Law ◽  
Stellar Mass ◽  
Direct Result ◽  
Mass Relation ◽  
Massive Galaxies ◽  
The Galaxy ◽  
Major Merger ◽  
Low Mass ◽  
Merger Rate

Abstract We explore the galaxy-galaxy merger rate with the empirical model for galaxy formation, emerge. On average, we find that between 2 per cent and 20 per cent of massive galaxies (log10(m*/M⊙) ≥ 10.3) will experience a major merger per Gyr. Our model predicts galaxy merger rates that do not scale as a power-law with redshift when selected by descendant stellar mass, and exhibit a clear stellar mass and mass-ratio dependence. Specifically, major mergers are more frequent at high masses and at low redshift. We show mergers are significant for the stellar mass growth of galaxies log10(m*/M⊙) ≳ 11.0. For the most massive galaxies major mergers dominate the accreted mass fraction, contributing as much as 90 per cent of the total accreted stellar mass. We reinforce that these phenomena are a direct result of the stellar-to-halo mass relation, which results in massive galaxies having a higher likelihood of experiencing major mergers than low mass galaxies. Our model produces a galaxy pair fraction consistent with recent observations, exhibiting a form best described by a power-law exponential function. Translating these pair fractions into merger rates results in an inaccurate prediction compared to the model intrinsic values when using published observation timescales. We find the pair fraction can be well mapped to the intrinsic merger rate by adopting an observation timescale that decreases linearly with redshift as Tobs = −0.36(1 + z) + 2.39 [Gyr], assuming all observed pairs merge by z = 0.

Single particle nature of the yrast line at high angular momentum in 152Dy

1979 ◽  
Vol 84 (2) ◽  
pp. 178-181 ◽  
Author(s):  
B. Haas ◽  
H.R. Andrews ◽  
O. Häusser ◽  
D. Horn ◽  
J.F. Sharpey-Schafer ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Single Particle ◽  
High Angular Momentum ◽  
Yrast Line ◽  
Particle Nature

High-Angular-Momentum States in Cold Rydberg Gases

2001 ◽  
Vol 86 (18) ◽  
pp. 3993-3996 ◽  
Author(s):  
S. K. Dutta ◽  
D. Feldbaum ◽  
A. Walz-Flannigan ◽  
J. R. Guest ◽  
G. Raithel
Keyword(s):  
Angular Momentum ◽  
High Angular Momentum

Persistence of octupole bands to high angular momentum in theA=80region

1989 ◽  
Vol 39 (3) ◽  
pp. 1158-1161 ◽  
Author(s):  
P. D. Cottle ◽  
O. N. Bignall
Keyword(s):  
Angular Momentum ◽  
High Angular Momentum

scholarly journals Fission cross sections as a probe of fusion dynamics at high angular momentum

2018 ◽  
Vol 98 (4) ◽  
Author(s):  
C. S. Palshetkar ◽  
D. J. Hinde ◽  
M. Dasgupta ◽  
E. Williams ◽  
K. Ramachandran ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Cross Sections ◽  
High Angular Momentum
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