TY  - JOUR
A1  - Johnson, Michael D.
A1  - Akiyama, Kazunori
A1  - Blackburn, Lindy
A1  - Bouman, Katherine L.
A1  - Broderick, Avery E.
A1  - Cardoso, Vitor
A1  - Fender, Rob P.
A1  - Fromm, Christian M.
A1  - Galison, Peter
A1  - Gómez, José L.
A1  - Haggard, Daryl
A1  - Lister, Matthew L.
A1  - Lobanov, Andrei P.
A1  - Markoff, Sera
A1  - Narayan, Ramesh
A1  - Natarajan, Priyamvada
A1  - Nichols, Tiffany
A1  - Pesce, Dominic W.
A1  - Younsi, Ziri
A1  - Chael, Andrew
A1  - Chatterjee, Koushik
A1  - Chaves, Ryan
A1  - Doboszewski, Juliusz
A1  - Dodson, Richard
A1  - Doeleman, Sheperd S.
A1  - Elder, Jamee
A1  - Fitzpatrick, Garret
A1  - Haworth, Kari
A1  - Houston, Janice
A1  - Issaoun, Sara
A1  - Kovalev, Yuri Y.
A1  - Levis, Aviad
A1  - Lico, Rocco
A1  - Marcoci, Alexandru
A1  - Martens, Niels C. M.
A1  - Nagar, Neil M.
A1  - Oppenheimer, Aaron
A1  - Palumbo, Daniel C. M.
A1  - Ricarte, Angelo
A1  - Rioja, María  J.
A1  - Roelofs, Freek
A1  - Thresher, Ann C.
A1  - Tiede, Paul
A1  - Weintroub, Jonathan
A1  - Wielgus, Maciek
T1  - Key science goals for the next-generation Event Horizon Telescope
JF  - Galaxies
N2  - The Event Horizon Telescope (EHT) has led to the first images of a supermassive black hole, revealing the central compact objects in the elliptical galaxy M87 and the Milky Way. Proposed upgrades to this array through the next-generation EHT (ngEHT) program would sharply improve the angular resolution, dynamic range, and temporal coverage of the existing EHT observations. These improvements will uniquely enable a wealth of transformative new discoveries related to black hole science, extending from event-horizon-scale studies of strong gravity to studies of explosive transients to the cosmological growth and influence of supermassive black holes. Here, we present the key science goals for the ngEHT and their associated instrument requirements, both of which have been formulated through a multi-year international effort involving hundreds of scientists worldwide.
KW  - black holes
KW  - general relativity
KW  - interferometry
KW  - accretion
KW  - relativistic jets
KW  - very-long-baseline interferometry
KW  - EHT
KW  - ngEHT
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-313525
SN  - 2075-4434
VL  - 11
IS  - 3
ER  - 
TY  - JOUR
A1  - Chatterjee, Koushik
A1  - Chael, Andrew
A1  - Tiede, Paul
A1  - Mizuno, Yosuke
A1  - Emami, Razieh
A1  - Fromm, Christian
A1  - Ricarte, Angelo
A1  - Blackburn, Lindy
A1  - Roelofs, Freek
A1  - Johnson, Michael D.
A1  - Doeleman, Sheperd S.
A1  - Arras, Philipp
A1  - Fuentes, Antonio
A1  - Knollmüller, Jakob
A1  - Kosogorov, Nikita
A1  - Lindahl, Greg
A1  - Müller, Hendrik
A1  - Patel, Nimesh
A1  - Raymond, Alexander
A1  - Traianou, Efthalia
A1  - Vega, Justin
T1  - Accretion flow morphology in numerical simulations of black holes from the ngEHT model library: the impact of radiation physics
JF  - Galaxies
N2  - In the past few years, the Event Horizon Telescope (EHT) has provided the first-ever event horizon-scale images of the supermassive black holes (BHs) M87* and Sagittarius A* (Sgr A*). The next-generation EHT project is an extension of the EHT array that promises larger angular resolution and higher sensitivity to the dim, extended flux around the central ring-like structure, possibly connecting the accretion flow and the jet. The ngEHT Analysis Challenges aim to understand the science extractability from synthetic images and movies to inform the ngEHT array design and analysis algorithm development. In this work, we compare the accretion flow structure and dynamics in numerical fluid simulations that specifically target M87* and Sgr A*, and were used to construct the source models in the challenge set. We consider (1) a steady-state axisymmetric radiatively inefficient accretion flow model with a time-dependent shearing hotspot, (2) two time-dependent single fluid general relativistic magnetohydrodynamic (GRMHD) simulations from the H-AMR code, (3) a two-temperature GRMHD simulation from the BHAC code, and (4) a two-temperature radiative GRMHD simulation from the KORAL code. We find that the different models exhibit remarkably similar temporal and spatial properties, except for the electron temperature, since radiative losses substantially cool down electrons near the BH and the jet sheath, signaling the importance of radiative cooling even for slowly accreting BHs such as M87*. We restrict ourselves to standard torus accretion flows, and leave larger explorations of alternate accretion models to future work.
KW  - black holes
KW  - general relativity
KW  - accretion
KW  - relativistic jets
KW  - very-long-baseline interferometry
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-304084
SN  - 2075-4434
VL  - 11
IS  - 2
ER  -