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Astronomers snap first-ever image of supermassive black hole Sagittarius A*（图）
超大质量黑洞 人马座A* 银河系
2023/6/9
Black holes are invisible by nature. Their pull is inescapable, forever trapping any light that falls into their gravitational abyss. But just beyond a black hole’s point of no return, light persists,...
A Two Micron All Sky Survey view of the Sagittarius dwarf galaxy. I. Morphology of the Sagittarius core and tidal arms
the Sagittarius core tidal arms
2014/12/24
We present the first all-sky view of the Sagittarius (Sgr) dwarf galaxy mapped by M-giant star tracers detected in the complete Two Micron All Sky Survey (2MASS). Near-infrared photometry of Sgr's pro...
We present high-resolution H41α hydrogen recombination line observations of the 12 (3 pc) region surrounding Sagittarius A* (Sgr A*) at 92 GHz using the Millimeter Array at the Owens Valley Radio Obse...
Dark Matter Constraints from the Sagittarius Dwarf and Tail System
the Sagittarius Dwarf Tail System
2014/12/24
2MASS has provided a three-dimensional map of the >360 degree, wrapped tidal tails of the Sagittarius (Sgr) dwarf spheroidal galaxy, as traced by M giant stars. With the inclusion of radial velocity d...
A Two Micron All Sky Survey view of the Sagittarius dwarf galaxy. II. Swope telescope spectroscopy of M giant stars in the dynamically cold Sagittarius tidal stream
kinematics halo
2014/12/24
We have obtained moderate resolution (~6 km s-1) spectroscopy of several hundred M giant candidates selected from Two Micron All Sky Survey photometry. Radial velocities are presented for stars mainly...
The 2Mass Color-magnitude Diagram of the Center of the Sagittarius Dwarf Galaxy: Photometric Measurements of a Surprisingly High Mean Metallicity
abundances stellar
2014/12/23
We present the Two Micron All Sky Survey (2MASS) (J−K, K) color-magnitude diagram for the region within 1◦ of the center of the Sagittarius dwarf spheroidal galaxy. Using the slope of the ...
Herschel observations of ortho- and para-oxidaniumyl (H2O+) in spiral arm clouds toward Sagittarius B2(M) *,**
H2O+ massive star forming
2014/12/22
H2O+ has been observed in its ortho- and para- states toward the massive star forming core Sgr B2(M), located close to the Galactic center. The observations show absorption in all spiral arm clouds be...
Herschel/HIFI measurements of the ortho/para ratio in water towards Sagittarius B2(M) and W31C*
gas dust
2014/12/22
We present Herschel/HIFI observations of the fundamental rotational transitions of ortho- and para-H216O and H218O in absorption towards Sagittarius B2(M) and W31C. The ortho/para ratio in water in th...
1.3 mm Wavelength VLBI of Sagittarius A*: Detection of Time-Variable Emission on Event Horizon Scales
Galaxy center — submillimeter general — techniques high angular resolution — techniques
2010/11/15
Sagittarius A*, the 4 × 106 M⊙ black hole candidate at the Galactic Center, can be studied on Schwarzschild radius scales with (sub)millimeter wavelength Very Long Baseline Interferometry (VLBI). We...
Synchrotron Blob Model of IR and X-ray Flares from Sagittarius A$^*$
acceleration of particles black hole physics Galaxy center radiation mechanisms: nonthermal
2010/11/11
Sagittarius A∗ in the Galactic center harbors a supermassive black hole and exhibits various active phenomena. Besides quiescent emission in radio and sub-millimeter radiation, flares in the nea...
Evidence for Low Black Hole Spin and Physically Motivated Accretion Models from Millimeter VLBI Observations of Sagittarius A*
black hole physics—Galaxy center—techniques interferometric—submillimeter—accretion accretion
2010/11/15
Millimeter very-long baseline interferometry (mm-VLBI) provides the novel capacity to probe the emission region of a handful of supermassive black holes on sub-horizon scales. For Sagittarius A* (Sgr ...
Massive and supermassive dust spheres (with a zero internal pressure) collapse to full globes of finite volumes, whose surfaces have the properties of the event horizon around a mass-point. This fact...
General Relativistic Magnetohydrodynamic and Monte Carlo Modeling of Sagittarius A*
accretion disc black hole Galactic Center magnetohydrodynamics
2010/11/11
We present results of models of the physical space and parameters of the accretion disk of Sagittarius A*, as well as simulations of its emergent spectrum.This begins with HARM, a 2D general relativis...
Spectral imaging of the Sagittarius B2 region in multiple 7-mm molecular lines
Galaxy Astrophysics (astro-ph.GA)
2010/12/29
We have undertaken a spectral-line imaging survey of a 6 x 6 arcmin^2 area around Sgr B2 near the centre of the Galaxy, in the range from 30 to 50 GHz, using the Mopra telescope. The spatial resolutio...
A past capture event at Sagittarius A* inferred from the fluorescent X-ray emission of Sagittarius B clouds
High Energy Astrophysical Phenomena (astro-ph.HE) Galaxy Astrophysics (astro-ph.GA)
2010/12/27
The fluorescent X-ray emission from neutral iron in the molecular clouds (Sgr B) indicates that the clouds are being irradiated by an external X-ray source. The source is probably associated with the ...