Results 21 to 30 of about 92,607 (277)

Highly Accreting Supermassive Black Holes as Eddington Standard Candles

Physical Sciences Forum, 2023
Supermassive black holes accreting matter at very high, perhaps even super-Eddington rates appear in the sky as a special class of luminous active galactic nuclei.
Paola Marziani
doaj   +1 more source

Testing loop quantum cosmology [PDF]

, 2017
Loop quantum cosmology predicts that quantum gravity effects resolve the big-bang singularity and replace it by a cosmic bounce. Furthermore, loop quantum cosmology can also modify the form of primordial cosmological perturbations, for example by ...
Wilson-Ewing, Edward
core   +2 more sources

The current status of observational cosmology [PDF]

, 2004
Observational cosmology has indeed made very rapid progress in recent years. The ability to quantify the universe has largely improved due to observational constraints coming from structure formation.
A A Starobinsky, A C Pope, A G Reiss, A H Guth, A Hajian, A Kogut, A Niarchou, A Shafieloo, C J Copi, C L Bennett, C Lacey, C Park, C R Contaldi, D Kirkman, D Munshi, D N Spergel, D N Spergel, D N Spergel, E Komatsu, G F Smoot, H K Eriksen, H K Eriksen, J L Tonry, J M Bardeen, J M Kovac, J P Ostriker, J R Bond, Jeremiah P. Ostriker, M Kaplinghat, M Tegmark, M Tegmark, N Bahcall, P Bode, P Colin, P J E Peebles, R H Cyburt, RAC Croft, T Padmanabhan, Tarun Souradeep, V Sahni, W Hu, W J Percival, W L Freedman   +42 more
core   +2 more sources

Observational Cosmology with Artificial Neural Networks

Universe, 2022
In cosmology, the analysis of observational evidence is very important when testing theoretical models of the Universe. Artificial neural networks are powerful and versatile computational tools for data modelling and have recently been considered in the ...
Juan de Dios Rojas Olvera, Isidro Gómez-Vargas, Jose Alberto Vázquez   +2 more
doaj   +1 more source

Towards an Observational Appraisal of String Cosmology

, 2011
We review the current observational status of string cosmology when confronted with experimental datasets. We begin by defining common observational parameters and discuss how they are determined for a given model.
Alabidi L, Arefeva I Y Belov D M Giryavets A A Koshelev A S Medvedev P B, Ashoorioon A Krause A, Babak S Gair J R Petiteau A Sesana A, Barnaby N, Barnaby N, Barnaby N, Baumann D, Berg M, Blanco-Pillado J J, Blanco-Pillado J J, Brandenberger R H, Brandenberger R H, Buchbinder E I, Buchbinder E I, Burgess C P, Burgess C P, Burgess C P, Burgess C P, Chen X, Chen X, Chen X, Cicoli M, Cicoli M, Cicoli M Mazumdar A, Cline J M, Conlon J P, Conlon J P, Conlon J P, Copeland E J, Cremades D, Danielsson U H, Das S, David J Mulryne, Denef F, Dietz A (LIGO Scientific Collaboration, Dimopoulos S, Dutta B, Easson D A, Easther R, Elliston J Mulryne D J Seery D Tavakol R, Firouzjahi H, Firouzjahi H, Flauger R, Fraisse A A, Guy J, Hannestad S, Huston I, John Ward, Kachru S, Khatri R Wandelt B D, Kobayashi T, Kofman L, Komatsu E, Koyama K, Koyama K, Krause A, Lehners J-L, Lidsey J E, Lyth D H, Lyth D H Liddle A R, Maldacena J M, Moniz P V, Palti E, Perlmutter S, Phinney E S, Planck Collaboration, Polchinski J, Polchinski J, Quevedo F, Raeymaekers J, Riess A G, Riess A G, Rigopoulos G I, Seery D, Sen A, Spergel D N, Spergel D N (WMAP Collaboration), Starobinsky A A, Thomas S, Vincent A C   +80 more
core   +1 more source

Temporal and Spectral Variability of OJ 287 before the April–June 2020 Outburst

Galaxies, 2020
We present the results of a temporal and spectral study of the BL Lacertae object OJ 287 in optical, UV, and X-ray bands with observations performed by Swift satellite during September 2019–March 2020.
Nibedita Kalita, Alok C. Gupta, Minfeng Gu   +2 more
doaj   +1 more source

Predicting cosmological observables with PyCosmo

Astronomy and Computing, 2021
Astronomy and Computing ...
F. Tarsitano, U. Schmitt, A. Refregier, J. Fluri, R. Sgier, A. Nicola, J. Herbel, A. Amara, T. Kacprzak, L. Heisenberg   +9 more
openaire   +3 more sources

Cross-correlating Dark Sirens and Galaxies: Constraints on H 0 from GWTC-3 of LIGO–Virgo–KAGRA

The Astrophysical Journal
We apply the cross-correlation technique to infer the Hubble constant ( H _0 ) of the Universe using gravitational-wave (GW) sources without electromagnetic counterparts (dark sirens) from the third GW Transient Catalog (GWTC-3) and the photometric ...
Suvodip Mukherjee, Alex Krolewski, Benjamin D. Wandelt, Joseph Silk   +3 more
doaj   +1 more source

Reheating via gravitational particle production in simple models of quintessence or $\Lambda$CDM inflation [PDF]

, 2017
We have tested some simple $\Lambda$CDM (the same test is also valid for quintessence) inflation models, imposing that they match with the recent observational data provided by the BICEP and Planck's team and leading to a reheating temperature, which is ...
Haro, Jaume, Saló, Llibert Aresté
core   +4 more sources

Photon‐Sphere Modes in Curved Optical Microcavities: A Black‐Hole Analogue Laser

Advanced Science, EarlyView.
An optical analogue of a Schwarzschild black hole is realized using curved microcavities that preserve light‐like geodesics. A new family of laser modes confined around the photon sphere is identified alongside conventional whispering‐gallery modes. Analytical theory, numerical simulations, and experiments reveal curvature‐induced confinement, enabling
Chenni Xu, Aswathy Sundaresan, Nazire‐Begüm Kazkal, Clement Lafargue, Lior Zarfaty, Li‐Gang Wang, Ofek Birnholtz, Dominique Decanini, Melanie Lebental, Patrick Sebbah   +9 more
wiley   +1 more source