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New observations of black hole devouring a star reveal rapid disk formation（图）
New observations black hole devouring star rapid disk formation
2020/9/11
When a star passes too close to a supermassive black hole, tidal forces tear it apart, producing a bright flare of radiation as material from the star falls into the black hole. Astronomers study the ...
Scientists discover massive rotating disk in early universe（图）
Scientists massive rotating disk early universe
2020/6/5
In the 13.8 billion-year-old universe, most galaxies form gradually, reaching their large mass relatively late.But the National Science Foundation-funded discovery of a massive rotating disk gala...
Constraints on mechanisms of chondrule formation from chondrule precursors and chronology of transient heating events in the protoplanetary disk
chondrules refractory inclusions chondrule precursors transient heating
2017/4/10
The mineralogy, petrography, and oxygen-isotope compositions of porphyritic chondrules—dominant chondrule type
in most chondrite groups—suggest formation by incomplete melting of isotopically diverse...
ALMA reveals planet-forming potential of protoplanetary disk
ALMA planet-forming potential protoplanetary disk
2016/2/23
Astronomers struggle to understand how planets form in binary star systems. Early models suggested that the gravitational tug-of-war between two stellar bodies would send young planets into eccentric ...
Gravitational instability and clustering in a disk of planetesimals
stars planetary systems protoplanetary disks – gravitation – planets satellites formation
2015/12/25
For a long time, gravitational instability in the disk of planetesimals has been suspected to be the main engine responsible for the beginning of dust growth, its advantage being that it provides forr...
Planetesimal clusters in a Keplerian disk I. gravitational evolution
planetary systems formation protoplanetary disks gravitation
2015/12/25
It was recently demonstrated by numerical simulations that a turbulent flow in a rotating system is capable of efficiently concentrating passively advected particles – having a density larger thanthe ...
Self-sustained mechanical vibrations of a disc-type micro-fabricated resonator were experimentally observed when a con-tinuous wave (CW) laser beam was focused on the periphery of the disc (for a 40 μ...
Numerical solution of a two-disk problem
Numerical solution control system and feedback compensator Fahrenheit convex programming numerical Fahrenheit programming
2015/8/12
A multidisk problem in frequency domain control system synthesis is a problem in which the designer wishes to find a feedback compensator that minimizes the H_infty-norm of a certain transfer matrix r...
Restrictions to Invariant Subspaces of Composition Operators on the Hardy Space of the Disk
composition operator hardy semigroup
2015/1/19
Invariant subspaces are a natural topic in linear algebra and operator theory. In some rare cases, the restrictions of operators to different invariant subspaces are unitarily equivalent, such as cert...
Commutants of composition operators on the Hardy space of the disk
Composition operator Commutant Hardy space
2015/1/19
The main part of this thesis, Chapter 4, contains results on the commutant of a semigroup of operators defined on the Hardy Space of the disk where the operators have hyperbolic non-automorphic symbol...
Study of Andromeda's stellar disk indicates more violent history than Milky Way（图）
Andromeda's stellar more violent history Milky Way
2015/1/20
A detailed study of the motions of different stellar populations in the disk of the Andromeda galaxy has found striking differences from our own Milky Way, suggesting a more violent history of mergers...
Chandra Observation of the Edge-on Galaxy NGC 3556 (M108): Violent Galactic Disk-Halo Interaction Revealed
NGC 3556 spiral
2014/12/26
We present a 60 ks Chandra ACIS-S observation of the isolated edge-on spiral galaxy NGC 3556, together with a multiwavelength analysis of various discrete X-ray sources and diffuse X-ray features. Amo...
I review results from Chandra observations of nearby normal edge-on galaxies (Sd to Sa types). These galaxies have a broad range of star formation rate, but none of them is dominated by a nuclear star...
We present high spatial resolution (51 × 27) Owens Valley Radio Observatory (OVRO) millimeter array observations of HCN (J = 1-0) and HCO+ (J = 1-0) emission in the inner 3 pc of the Galaxy (0.04 pc ~...
Galaxy merger statistics and inferred bulge-to-disk ratios in cosmological SPH simulations
formation spiral elliptical
2014/12/24
We construct merger trees for galaxies identified in a cosmological hydrodynamic simulation and use them to characterize predicted merger rates as a function of redshift, galaxy mass, and merger mass ...