Results 21 to 30 of about 163,876 (250)

PAWS and POCO: NIR Astrophotonic Instruments for Astronomy

Astronomische Nachrichten, Volume 344, Issue 8-9, October-November 2023., 2023
Abstract For near‐infrared ground and space‐based astronomy, compact photonic devices can replace the large bulk optical components in spectrographs, frequency combs, beam combiners, and sky subtraction filters, thus saving cost, reducing volume, weight, and power requirements.
Kalaga Madhav, Alan Günther, Eloy Hernandez, Stella Vjes̆nica, Daniel Bodenmüller, Andreas Stoll, Christer Sandin, Haydar Altuğ Yıldırım, Martin M. Roth   +8 more
wiley   +1 more source

Epicyclic Oscillations around Simpson–Visser Regular Black Holes and Wormholes

Universe, 2021
We study epicyclic oscillatory motion along circular geodesics of the Simpson–Visser meta-geometry describing in a unique way regular black-bounce black holes and reflection-symmetric wormholes by using a length parameter l.
Zdeněk Stuchlík, Jaroslav Vrba
doaj   +1 more source

First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole [PDF]

, 2019
When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon.
The Event Horizon Telescope Collaboration
semanticscholar   +1 more source

Characterization of a C‐RED One camera for astrophotonical applications

Astronomische Nachrichten, Volume 344, Issue 8-9, October-November 2023., 2023
Abstract To better understand the impact of the avalanche gain applied in the detector technology and apply this technology in our in‐house astrophotonic projects, we have characterized a C‐RED One camera and produced a stable and reliable method for calculating the system gain at any desired avalanche gain setting.
Stella Vješnica, Eloy Hernandez, Kalaga Madhav, Martin M. Roth   +3 more
wiley   +1 more source

UNCOVER: The Growth of the First Massive Black Holes from JWST/NIRSpec—Spectroscopic Redshift Confirmation of an X-Ray Luminous AGN at z = 10.1 [PDF]

Astrophysical Journal Letters, 2023
The James Webb Space Telescope is now detecting early black holes (BHs) as they transition from “seeds” to supermassive BHs. Recently, Bogdan et al. reported the detection of an X-ray luminous supermassive BH, UHZ-1, with a photometric redshift at z > 10.
A. Goulding, J. Greene, D. Setton, I. Labbé, R. Bezanson, T. Miller, H. Atek, Á. Bogdán, G. Brammer, Iryna Chemerynska, Sam E. Cutler, P. Dayal, Y. Fudamoto, S. Fujimoto, L. Furtak, V. Kokorev, G. Khullar, J. Leja, D. Marchesini, P. Natarajan, E. Nelson, P. Oesch, R. Pan, C. Papovich, S. Price, P. V. van Dokkum, B. Wang 王, J. Weaver, K. Whitaker, A. Zitrin   +29 more
semanticscholar   +1 more source

Perturbative Solution of the Einstein Constraints with Spin and Momentum Far Away From a Binary Source in the Bowen‐York Formalism

Fortschritte der Physik, Volume 71, Issue 8-9, September 2023., 2023
Abstract The momentum and Hamiltonian constraints of vacuum Einstein equations, within the Bowen‐York formalism, for two interacting black holes in close separation, with anti‐parallel spins and anti‐parallel linear momenta is studied. An analytical solution using perturbation theory is given.
Emel Altas, Emine Ertugrul, Bayram Tekin
wiley   +1 more source

Investigation of some galactic and extragalactic gravitational phenomena [PDF]

Serbian Astronomical Journal, 2012
Here we present a short overview of the most important results of our investigations of the following galactic and extragalactic gravitational phenomena: supermassive black holes in centers of galaxies and quasars, supermassive black hole ...
Jovanović P.
doaj   +1 more source

A tool to understand emission mechanisms of blazars through their high‐energy gamma‐ray emission

Astronomische Nachrichten, Volume 344, Issue 6, August 2023., 2023
The blazar SED is characterized by two energy components. Evidence suggests that the low‐energy component is generated by the synchrotron mechanism, but for the high‐energy component, the mechanism is still uncertain. Two main models have been proposed to explain this emission. According to the leptonic model, a correlation between the emission of both
Mabel Osorio, Erick Rangel, José Rodrigo Sacahui, María Magdalena González   +3 more
wiley   +1 more source

Unraveling the enigmatic soft x‐ray excess: Current understanding and future perspectives

Astronomische Nachrichten, Volume 344, Issue 6, August 2023., 2023
Abstract This article explores various theoretical models proposed to explain the soft x‐ray excess phenomenon, including warm Comptonization, ionized reflection models, and ionized outflowing disc winds. The soft x‐ray excess is better understood thanks to crucial observations made by ROSAT, XMM‐Newton, and eROSITA.
Thomas Boller
wiley   +1 more source

Modeling the Central Supermassive Black Hole Mass of Quasars via the LSTM Approach

The Astrophysical Journal, 2023
One of the fundamental questions about quasars is related to their central supermassive black holes. The reason for the existence of these black holes with such a huge mass is still unclear, and various models have been proposed to explain them. However,
Seyed Sajad Tabasi, Reyhaneh Vojoudi Salmani, Pouriya Khaliliyan, Javad T. Firouzjaee   +3 more
doaj   +1 more source