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The second-generation beam combiner at the Very Large Telescope (VLT), GRAVITY, observes the stars orbiting the compact object located at the center of our galaxy, with an unprecedented astrometric accuracy of 10 $\mu$as. The nature of this…

High Energy Astrophysical Phenomena · Physics 2017-11-22 M. Grould , Z. Meliani , F. H. Vincent , P. Grandclément , E. Gourgoulhon

The origin of irradiation and fluorescence of the 6.4 keV bright giant molecular clouds surrounding Sgr A*, the central supermassive black hole of our Galaxy, remains enigmatic. Testing the theory of a past active period of Sgr A* requires…

Astrophysics of Galaxies · Physics 2015-03-18 F. Marin , F. Muleri , P. Soffitta , V. Karas , D. Kunneriath

We study an interstellar signaling scheme which was originally proposed by Seto (2019) and efficiently links intentional transmitters to ETI searchers through a conspicuous astronomical burst, without prior communication. Based on the…

Instrumentation and Methods for Astrophysics · Physics 2021-09-08 Naoki Seto

As the closest example of a galactic nucleus, the Galactic center presents an exquisite laboratory for learning about supermassive black holes (SMBH) and their environs. Detailed studies of stellar dynamics deep in the potential well of a…

We present a new directly-observable statistic which uses sky position and proper motion of stars near the Galactic center massive black hole to identify populations with high orbital eccentricities. It is most useful for stars with large…

Astrophysics of Galaxies · Physics 2015-06-15 Ann-Marie Madigan , Oliver Pfuhl , Yuri Levin , Stefan Gillessen , Reinhard Genzel , Hagai B. Perets

We consider the time derivatives of the period $P$ of pulsars at the Galactic Center due to variations in their orbital Doppler shifts. We show that in conjunction with a measurement of a pulsar's proper motion and its projected separation…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 Pierre Christian , Abraham Loeb

In the centre of our galaxy lies a super-massive black hole, identified with the radio source Sagittarius A*. This black hole has an estimated mass of around 4 million solar masses. Although Sagittarius A* is quite dim in terms of total…

High Energy Astrophysical Phenomena · Physics 2016-09-02 Michael Walls , Maria Chernyakova , Regis Terrier , Andrea Goldwurm

We use recently updated globular cluster distances to estimate the distance to the Galactic centre, finding 7.4 \pm 0.2|stat \pm 0.2|sys kpc from symmetry considerations. We recalibrate the red clump magnitude from Hipparcos stars, finding…

Astrophysics of Galaxies · Physics 2014-05-13 Charles Francis , Erik Anderson

A line-of-sight towards the Galactic Center (GC) offers the largest number of potentially habitable systems of any direction in the sky. The Breakthrough Listen program is undertaking the most sensitive and deepest targeted SETI surveys…

We report 75 milli-arcsec resolution, near-IR imaging spectroscopy within the central 30 light days of the Galactic Center [...]. To a limiting magnitude of K~16, 9 of 10 stars in the central 0.4 arcsec, and 13 of 17 stars out to 0.7 arcsec…

Several stars orbit around a black hole candidate of mass $3.7\times 10^6$ M$_{\odot}$, in the region of the Galactic Center (GC). Looking for General Relativistic (GR) periastron shifts is limited by the existence of a stellar cluster…

Astrophysics · Physics 2015-05-13 A. A. Nucita , F. De Paolis , G. Ingrosso , A. Qadir , A. F. Zakharov

Context. In addition to the supermassive black hole Sgr A*, the inner parsec of our Galactic center is home to numerous fruitful scientific habitats. One of these environments is the S cluster, which consists of two distinct populations:…

Astrophysics of Galaxies · Physics 2025-12-01 F. Peißker , M. Zajacek , V. Karas , V. Pavlík , E. Bordier , L. Šubr , J. Haas , M. Melamed , L. Großekathöfer , N. Schmökel , M. Singhal

The Galactic Center hosts a rotating disk of young stars between 0.05 and 0.5 pc of Sgr A*. The ``S-stars'' at a distance $<0.04$ pc, however, are on eccentric orbits with nearly isotropically distributed inclinations. The dynamical origin…

Astrophysics of Galaxies · Physics 2024-11-14 Tatsuya Akiba , Smadar Naoz , Ann-Marie Madigan

We measure the proper motion of the pulsar PSR J1745-2900 relative to the Galactic Center massive black hole, Sgr A*, using the Very Long Baseline Array (VLBA). The pulsar has a transverse velocity of 236 +/- 11 km s^-1 at position angle 22…

We advocate for a Galactic center (GC) field to be added to the Galactic Bulge Time Domain Survey (GBTDS). The new field would yield high-cadence photometric and astrometric measurements of an unprecedented ${\sim}$3.3 million stars toward…

Gas clouds are present in the Galactic centre, where they orbit around the supermassive black hole. Collisions between these clumps reduce their angular momentum, and as a result some of the clumps are set on a plunging trajectory.…

High Energy Astrophysical Phenomena · Physics 2013-07-09 Bozena Czerny , Devaky Kunneriath , Vladimir Karas , Tapas K. Das

Pulsars around the Massive Black Hole (MBH) in the Galactic Center (GC) are expected to be revealed by the incoming facilities (e.g., the Square Kilometre Array). Under a full relativistic framework with the pulsar approximated as a test…

Astrophysics of Galaxies · Physics 2019-02-04 Fupeng Zhang , Prasenjit Saha

We consider a static, spherically symmetric space-time with an electric field arising from a quadratic metric-affine extension of General Relativity. Such a space-time is free of singularities in the centre of the black holes, while at…

General Relativity and Quantum Cosmology · Physics 2024-01-17 Ivan De Martino , Riccardo Della Monica , Diego Rubiera-Garcia
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