Results 11 to 20 of about 21,097,663 (248)

Potential impact of the Sagittarius dwarf galaxy on the formation of young O-rich stars [PDF]

open access: yesNature Communications
The Milky Way underwent significant transformations in its early history, characterised by violent mergers and satellite galaxy accretion. However, recent observations reveal notable star formation events over the past 4 Gyr, likely triggered by ...
Tiancheng Sun   +12 more
doaj   +2 more sources

Orbital motion near Sagittarius A* [PDF]

open access: yesAstronomy & Astrophysics, 2022
نبلغ عن منحنيات الضوء المستقطبة للثقب الأسود الهائل في مركز المجرة Sagittarius A * ، والتي تم الحصول عليها بطول موجي ملليمتر باستخدام مصفوفة Atacama Large Millimeter/submillimeter Array (ALMA). تمت الملاحظات كجزء من حملة Event Horizon Telescope. نقارن الملاحظات التي تم أخذها خلال حالة مصدر التباين المنخفض في 6 و 7 أبريل 2017 مع تلك التي تم أخذها مباشرة
Maciek Wielgus   +8 more
openaire   +2 more sources

Deformed black hole in Sagittarius A [PDF]

open access: yesPhysical Review D, 2021
We analyze the post-Newtonian orbit of stars around a deformed Kerr black hole. The deformation we consider is a class of disformal transformations of a nontrivial Kerr solution in scalar-tensor theory which are labeled via the disformal parameter $D$. We study different limits of the disformal parameter, and compare the trajectories of stars orbiting ...
T. Anson, E. Babichev, C. Charmousis
openaire   +5 more sources

First Sagittarius A* Event Horizon Telescope Results. VII. Polarization of the Ring

open access: yesThe Astrophysical Journal Letters
The Event Horizon Telescope observed the horizon-scale synchrotron emission region around the Galactic center supermassive black hole, Sagittarius A* (Sgr A*), in 2017. These observations revealed a bright, thick ring morphology with a diameter of 51.8 ±
The Event Horizon Telescope Collaboration   +285 more
doaj   +2 more sources

The Proper Motion of Sagittarius A*. III. The Case for a Supermassive Black Hole [PDF]

open access: bronzeAstrophysical Journal, 2020
We report measurements with the Very Long Baseline Array of the proper motion of Sgr A* relative to two extragalactic radio sources spanning 18 yr. The apparent motion of Sgr A* is −6.411 ± 0.008 mas yr−1 along the Galactic plane and −0.219 ± 0.007 mas ...
M. J. Reid, A. Brunthaler
openalex   +3 more sources

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A ∗ [PDF]

open access: yesClassical and quantum gravity, 2022
Horizon-scale images of black holes (BHs) and their shadows have opened an unprecedented window onto tests of gravity and fundamental physics in the strong-field regime.
S. Vagnozzi   +3 more
semanticscholar   +1 more source

First Sagittarius A* Event Horizon Telescope Results. VI. Testing the Black Hole Metric [PDF]

open access: yesAstrophysical Journal Letters, 2022
Astrophysical black holes are expected to be described by the Kerr metric. This is the only stationary, vacuum, axisymmetric metric, without electromagnetic charge, that satisfies Einstein’s equations and does not have pathologies outside of the event ...
K. Akiyama   +269 more
semanticscholar   +1 more source

First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way [PDF]

open access: yes, 2023
We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A$^*$), the Galactic center source associated with a supermassive black hole.
K. Akiyama   +387 more
semanticscholar   +1 more source

Overionized plasma in the supernova remnant Sagittarius A East anchored by XRISM observations [PDF]

open access: hybridNippon Tenmon Gakkai obun kenkyu hokoku
Sagittarius A East is a supernova remnant with a unique surrounding environment, as it is located in the immediate vicinity of the supermassive black hole at the Galactic center, Sagittarius A$^{*}$.
M. Audard   +99 more
openalex   +3 more sources

First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole [PDF]

open access: yesAstrophysical Journal Letters, 2022
In this paper we provide a first physical interpretation for the Event Horizon Telescope's (EHT) 2017 observations of Sgr A*. Our main approach is to compare resolved EHT data at 230 GHz and unresolved non-EHT observations from radio to X-ray ...
K. Akiyama   +273 more
semanticscholar   +1 more source

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