| Title | Tracing Hot Spot Motion in Sagittarius A* Using the Next-Generation Event Horizon Telescope (ngEHT) |
| Authors | Emami, Razieh Tiede, Paul Doeleman, Sheperd S. Roelofs, Freek Wielgus, Maciek Blackburn, Lindy Liska, Matthew Chatterjee, Koushik Ripperda, Bart Fuentes, Antonio Broderick, Avery E. Hernquist, Lars Alcock, Charles Narayan, Ramesh Smith, Randall Tremblay, Grant Ricarte, Angelo Sun, He Anantua, Richard Kovalev, Yuri Y. Natarajan, Priyamvada Vogelsberger, Mark |
| Affiliation | Ctr Astrophys Harvard & Smithsonian, 60 Garden St, Cambridge, MA 02138 USA Harvard Univ, Black Hole Initiat, 20 Garden St, Cambridge, MA 02138 USA Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany Inst Adv Study, Sch Nat Sci, 1 Einstein Dr, Princeton, NJ 08540 USA NASA Hubble Fellowship Program, Baltimore, MD USA Inst Astrofis Andalucia CSIC, Glorieta Astron S-N, E-18008 Granada, Spain Perimeter Inst Theoret Phys, 31 Caroline St North, Waterloo, ON N2L 2Y5, Canada Univ Waterloo, Dept Phys & Astron, 200 Univ Ave West, Waterloo, ON N2L 3G1, Canada Peking Univ, Coll Future Technol, Natl Biomed Imaging Ctr, Beijing 100871, Peoples R China Univ Texas San Antonio, Dept Phys & Astron, One UTSA Circle, San Antonio, TX 78249 USA Russian Acad Sci, Lebedev Phys Inst, Leninsky Prospekt 53, Moscow 119991, Russia Moscow Inst Phys & Technol, Inst Sky per 9, Dolgoprudnyi 141700, Russia Yale Univ, Dept Astron, New Haven, CT 06511 USA Yale Univ, Dept Phys, New Haven, CT 06520 USA MIT, Dept Phys, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA |
| Keywords | SUPERMASSIVE BLACK-HOLE NEAR-INFRARED FLARES ADVECTION-DOMINATED ACCRETION X-RAY EMISSION RADIO DISK MM |
| Issue Date | Feb-2023 |
| Publisher | GALAXIES |
| Abstract | We propose the tracing of the motion of a shearing hot spot near the Sgr A* source through a dynamical image reconstruction algorithm, StarWarps. Such a hot spot may form as the exhaust of magnetic reconnection in a current sheet near the black hole horizon. A hot spot that is ejected from the current sheet into an orbit in the accretion disk may shear and diffuse due to instabilities at its boundary during its orbit, resulting in a distinct signature. We subdivide the motion into two different phases: the first phase refers to the appearance of the hot spot modeled as a bright blob, followed by a subsequent shearing phase. We employ different observational array configurations, including EHT (2017, 2022) and the next-generation Event Horizon Telescope (ngEHTp1, ngEHT) arrays, with several new sites added, and make dynamical image reconstructions for each of them. Subsequently, we infer the hot spot angular image location in the first phase, followed by the axes ratio and the ellipse area in the second phase. We focus on the direct observability of the orbiting hot spot in the sub-mm wavelength. Our analysis demonstrates that for this particular simulation, the newly added dishes are better able to trace the first phase as well as part of the second phase before the flux is reduced substantially, compared to the EHT arrays. The algorithm used in this work can be easily extended to other types of dynamics, as well as different shearing timescales. More simulations are required to prove whether the current set of newly proposed sites are sufficient to resolve any motions near variable sources, such as Sgr A*. |
| URI | http://hdl.handle.net/20.500.11897/672148 |
| DOI | 10.3390/galaxies11010023 |
| Indexed | ESCI |
| Appears in Collections: | 待认领 |
