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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 ...
Isidro Gómez-Vargas, Jose Alberto Vazquez   +1 more
exaly   +4 more sources

Observational constraints on the fractal cosmology [PDF]

European Physical Journal C: Particles and Fields, 2022
In this paper, we explore a fractal model of the universe proposed by Calcagni (J High Energy Phys 03:120, 2010) for a power-counting renormalizable field theory living in a fractal spacetime.
Mahnaz Asghari, Ahmad Sheykhi
doaj   +2 more sources

Sample Variance in Cosmological Observations with a Narrow Field of View

The Astrophysical Journal, 2023
Surveys with a narrow field of view can play an important role in probing cosmology, but inferences from these surveys suffer from large sample variance, arising from random fluctuations around the cosmic mean.
Peter Espenshade, Jaiyul Yoo
doaj   +1 more source

The DESI Survey Validation: Results from Visual Inspection of the Quasar Survey Spectra

The Astronomical Journal, 2023
A key component of the Dark Energy Spectroscopic Instrument (DESI) survey validation (SV) is a detailed visual inspection (VI) of the optical spectroscopic data to quantify key survey metrics. In this paper we present results from VI of the quasar survey
David M. Alexander, Tamara M. Davis, E. Chaussidon, V. A. Fawcett, Alma X. Gonzalez-Morales, Ting-Wen Lan, Christophe Yèche, S. Ahlen, J. N. Aguilar, E. Armengaud, S. Bailey, D. Brooks, Z. Cai, R. Canning, A. Carr, S. Chabanier, Marie-Claude Cousinou, K. Dawson, A. de la Macorra, A. Dey, Biprateep Dey, G. Dhungana, A. C. Edge, S. Eftekharzadeh, K. Fanning, James Farr, A. Font-Ribera, J. Garcia-Bellido, Lehman Garrison, E. Gaztañaga, Satya Gontcho A Gontcho, C. Gordon, Stefany Guadalupe Medellin Gonzalez, J. Guy, Hiram K. Herrera-Alcantar, L. Jiang, S. Juneau, N. G. Karaçaylı, R. Kehoe, T. Kisner, A. Kovács, M. Landriau, Michael E. Levi, C. Magneville, P. Martini, Aaron M. Meisner, M. Mezcua, R. Miquel, P. Montero Camacho, J. Moustakas, Andrea Muñoz-Gutiérrez, Adam D. Myers, S. Nadathur, L. Napolitano, J. D. Nie, N. Palanque-Delabrouille, Z. Pan, W. J. Percival, I. Pérez-Ràfols, C. Poppett, F. Prada, César Ramírez-Pérez, C. Ravoux, D. J. Rosario, M. Schubnell, Gregory Tarlé, M. Walther, B. Weiner, S. Youles, Zhimin Zhou, H. Zou, Siwei Zou   +71 more
doaj   +1 more source

Performance of the Quasar Spectral Templates for the Dark Energy Spectroscopic Instrument

The Astronomical Journal, 2023
Millions of quasar spectra will be collected by the Dark Energy Spectroscopic Instrument (DESI), leading to a fourfold increase in the number of known quasars.
Allyson Brodzeller, Kyle Dawson, Stephen Bailey, Jiaxi Yu, A. J. Ross, A. Bault, S. Filbert, J. Aguilar, S. Ahlen, David M. Alexander, E. Armengaud, A. Berti, D. Brooks, E. Chaussidon, A. de la Macorra, P. Doel, K. Fanning, V. A. Fawcett, A. Font-Ribera, S. Gontcho A Gontcho, J. Guy, K. Honscheid, S. Juneau, R. Kehoe, T. Kisner, Anthony Kremin, Ting-Wen Lan, M. Landriau, Michael E. Levi, C. Magneville, Paul Martini, Aaron M. Meisner, R. Miquel, J. Moustakas, N. Palanque-Delabrouille, W. J. Percival, F. Prada, C. Ravoux, Graziano Rossi, C. Saulder, M. Siudek, Gregory Tarlé, B. A. Weaver, S. Youles, Zheng Zheng, Rongpu Zhou, Zhimin Zhou   +46 more
doaj   +1 more source

The DESI Survey Validation: Results from Visual Inspection of Bright Galaxies, Luminous Red Galaxies, and Emission-line Galaxies

The Astrophysical Journal, 2023
The Dark Energy Spectroscopic Instrument (DESI) Survey has obtained a set of spectroscopic measurements of galaxies to validate the final survey design and target selections.
Ting-Wen Lan, R. Tojeiro, E. Armengaud, J. Xavier Prochaska, T. M. Davis, David M. Alexander, A. Raichoor, Rongpu Zhou, Christophe Yèche, C. Balland, S. BenZvi, A. Berti, R. Canning, A. Carr, H. Chittenden, S. Cole, M.-C. Cousinou, K. Dawson, Biprateep Dey, K. Douglass, A. Edge, S. Escoffier, A. Glanville, S. Gontcho A Gontcho, J. Guy, C. Hahn, C. Howlett, Ho Seong Hwang, L. Jiang, A. Kovács, M. Mezcua, S. Moore, S. Nadathur, M. Oh, D. Parkinson, A. Rocher, A. J. Ross, V. Ruhlmann-Kleider, C. G. Sabiu, K. Said, C. Saulder, D. Sierra-Porta, B. Weiner, J. Yu, P. Zarrouk, Y. Zhang, H. Zou, S. Ahlen, S. Bailey, D. Brooks, A. P. Cooper, A. de la Macorra, A. Dey, G. Dhungana, P. Doel, S. Eftekharzadeh, K. Fanning, A. Font-Ribera, L. Garrison, E. Gaztañaga, R. Kehoe, T. Kisner, A. Kremin, M. Landriau, L. Le Guillou, Michael E. Levi, C. Magneville, Aaron M. Meisner, R. Miquel, J. Moustakas, Adam D. Myers, Jeffrey A. Newman, J. D. Nie, N. Palanque-Delabrouille, W. J. Percival, C. Poppett, F. Prada, M. Schubnell, Gregory Tarlé, B. A. Weaver, K. Zhang, Zhimin Zhou   +81 more
doaj   +1 more source

Observational constraints on soft dark energy and soft dark matter: Challenging ΛCDM cosmology

Nuclear Physics B, 2023
Soft cosmology is an extension of standard cosmology allowing for a scale-dependent equation-of-state (EoS) parameter in the dark sectors, which is one of the properties of soft materials in condensed-matter physics, that may arise either intrinsically ...
Emmanuel N. Saridakis, Weiqiang Yang, Supriya Pan, Fotios K. Anagnostopoulos, Spyros Basilakos   +4 more
doaj   +1 more source

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

Low-Redshift Observational Constraints on Dark Energy Cosmologies [PDF]

Iranian Journal of Astronomy and Astrophysics, 2023
Applying the Markov chain Monte Carlo algorithm and using low-redshift observational data, we put cosmological constraints on dark energy cosmologies. Our main aim is to show the influence of each data sample on the procedure of constraining.
Mohammad Malekjani
doaj   +1 more source

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