Results 31 to 40 of about 21,097,663 (248)

Prospects for constraining the Yukawa gravity with pulsars around Sagittarius A* [PDF]

Journal of Cosmology and Astroparticle Physics, 2022
The discovery of radio pulsars (PSRs) around the supermassive black hole (SMBH) in our Galactic Center (GC), Sagittarius A* (Sgr A*), will have significant implications for tests of gravity. In this paper, we predict restrictions on the parameters of the
Yiming Dong, Lijing Shao, Zexin Hu, X. Miao, Ziming Wang   +4 more
semanticscholar   +1 more source

Persistent Non-Gaussian Structure in the Image of Sagittarius A* at 86 GHz [PDF]

Astrophysical Journal, 2021
Observations of the Galactic Center supermassive black hole Sagittarius A* (Sgr A*) with very long-baseline interferometry (VLBI) are affected by interstellar scattering along our line of sight. At long radio observing wavelengths (≲1 cm), the scattering
S. Issaoun, M. Johnson, L. Blackburn, A. Broderick, P. Tiede, M. Wielgus, S. Doeleman, H. Falcke, K. Akiyama, G. Bower, C. Brinkerink, A. Chael, I. Cho, J. G'omez, A. Hernández-Gómez, D. Hughes, M. Kino, T. Krichbaum, E. Liuzzo, L. Loinard, S. Markoff, D. Marrone, Y. Mizuno, J. Moran, Y. Pidopryhora, E. Ros, K. Rygl, Z. Shen, J. Wagner   +28 more
semanticscholar   +1 more source

Multiwavelength Variability of Sagittarius A* in 2019 July [PDF]

Astrophysical Journal, 2022
We report a timing analysis of near-infrared (NIR), X-ray, and submillimeter data during a 3 day coordinated campaign observing Sagittarius A*. Data were collected at 4.5 μm with the Spitzer Space Telescope, 2–8 keV with the Chandra X-ray Observatory, 3 ...
H. Boyce, D. Haggard, G. Witzel, S. Fellenberg, S. Willner, E. Becklin, T. Do, A. Eckart, G. Fazio, M. Gurwell, J. Hora, S. Markoff, M. Morris, J. Neilsen, M. Nowak, H. Smith, S. Zhang   +16 more
semanticscholar   +1 more source

Remarkable Correspondence of the Sagittarius A* Submillimeter Variability with a Stellar-wind-fed Accretion Flow Model [PDF]

Astrophysical Journal Letters, 2022
We compare the 230 GHz near-horizon emission from Sagittarius A* to simulations representing three classes of accretion flows. Using the structure function to capture the variability statistics of the light curve, we find a noticeable discrepancy between
L. Murchikova, C. White, S. Ressler
semanticscholar   +1 more source

POLARIZED EMISSION OF SAGITTARIUS A* [PDF]

The Astrophysical Journal, 2009
We explore the parameter space of the two temperature pseudo-Newtonian Keplerian accretion flow model for the millimeter and shorter wavelength emission from Sagittarius A*. A general relativistic ray-tracing code is used to treat the radiative transfer of polarized synchrotron emission from the flow.
Huang, Lei, Liu, Siming, Shen, Zhi-Qiang, Yuan, Ye-Fei, Cai, Mike J., Li, Hui, Fryer, Christopher L.   +6 more
openaire   +2 more sources

The Intrinsic Structure of Sagittarius A* at 1.3 cm and 7 mm [PDF]

Astrophysical Journal, 2021
Sagittarius A* (Sgr A*), the Galactic Center supermassive black hole (SMBH), is one of the best targets in which to resolve the innermost region of an SMBH with very long baseline interferometry (VLBI).
I. Cho, Guangyao Zhao, T. Kawashima, M. Kino, K. Akiyama, Michael D. Johnson, S. Issaoun, K. Moriyama, Xiaopeng Cheng, J. Algaba, T. Jung, B. Sohn, T. Krichbaum, M. Wielgus, K. Hada, R. Lu, Yuzhu Cui, S. Sawada-Satoh, Zhiqiang Shen, Jongho Park, Wu Jiang, H. Ro, K. -H. Yi, K. Wajima, J. Lee, J. Hodgson, F. Tazaki, M. Honma, K. Niinuma, S. Trippe, T. An, Yingkang Zhang, J. Lee, Se-jin Oh, D. Byun, Sang-Sung Lee, Jae-Young Kim, J. Oh, S. Koyama, K. Asada, Xuezheng Wang, L. Cui, Y. Hagiwara, M. Nakamura, M. Takamura, T. Hirota, K. Sugiyama, N. Kawaguchi, H. Kobayashi, T. Oyama, Y. Yonekura, Jongsoo Kim, Ju-Yeon Hwang, Dong-Kyu Jung, Hyo-Ryoung Kim, Jeong-Sook Kim, C. Oh, D. Roh, J. Yeom, B. Xia, Weiye Zhong, Bin Li, Rongbin Zhao, Jinqing Wang, Qing-Hui Liu, Zhong Chen Korea Astronomy, Space Telescope Science Institute, University of Electronic Science, Technology, Instituto de Astrofisica de Andalucia-CSIC, Inst. for Nucl. Research, T. U. O. Tokyo, N. A. O. O. Japan, Kogakuin University of Technology, Engineering, Massachusetts Institute of TechnologyHaystack Observatory, Black Hole Initiative at Harvard University, Center for Computational Astrophysics, Harvard, Smithsonian, D. O. Astrophysics, Institute for Mathematics, Astrophysics, P. Physics, R. University, Mizusawa Vlbi Observatory, Department of Materials Science, U. Malaya, D. O. Astronomy, Yonsei University, M. F. Radioastronomie, Department of Materials Science, The Graduate University for Advanced Studies, S. Observatory, Key Laboratory of Optical Astronomy, The Graduate University for Advanced Studies, Y. University, I. O. Astronomy, A. Sinica, D. Physics, Astronomy, Seoul National University, Sejong University, G. S. O. Sciences, Technology for Innovation, Snu Astronomy Research Center, Niigata University, Xinjiang Astronomical Observatory, Toyo University, National Institute of Technology, Hachinohe College, National Astronomical Research Institute of Thailand, C. F. Astronomy, I. University, B. S. R. Institute, Chungbuk National University   +115 more
semanticscholar   +1 more source

Ab Initio Horizon-scale Simulations of Magnetically Arrested Accretion in Sagittarius A* Fed by Stellar Winds [PDF]

Astrophysical Journal, 2020
We present 3D general relativistic magnetohydrodynamic (GRMHD) simulations of the accretion flow surrounding Sagittarius A* that are initialized using larger-scale MHD simulations of the ∼30 Wolf–Rayet (WR) stellar winds in the Galactic center.
S. Ressler, C. White, E. Quataert, J. Stone   +3 more
semanticscholar   +1 more source

Unexpected discovery of a new Podonychus species in Kyushu, Japan (Coleoptera, Elmidae, Elminae, Macronychini) [PDF]

ZooKeys, 2020
Podonychus gyobu sp. nov., a second species of the genus Podonychus Jäch & Kodada, 1997, hitherto known only from Indonesia, is described from Kyushu, Japan. This new species is similar to P.
Hiroyuki Yoshitomi, Masakazu Hayashi
doaj   +3 more sources

Review of Palaearctic species of the Dolichopus sagittarius group Loew, 1848 (Diptera: Dolichopodidae), with description of a new species from Kazakhstan [PDF]

Кавказский энтомологический бюллетень, 2013
Type specimen of Dolichopus sagittarius Loew, 1848, D. reichardti Stackelberg, 1930, D. grunini Smirnov, 1948 and D. portentosus Negrobov, 1973 are examined and male genitalia are illustrated for the first time.
O.P. Negrobov, O.V. Selivanova, O.O. Maslova   +2 more
doaj   +1 more source

Quantum gravity effects around Sagittarius A* [PDF]

International Journal of Modern Physics D, 2016
Recent VLBI observations have resolved Sagittarius A* at horizon scales. The event horizon telescope is expected to provide increasingly good images of the region around the Schwarzschild radius [Formula: see text] of Sgr A* soon. A number of authors have recently pointed out the possibility that nonperturbative quantum gravitational phenomena could ...
Haggard, Hal, Rovelli, Carlo
openaire   +3 more sources