Results 1 to 10 of about 92,572 (312)

Observational Cosmology with Artificial Neural Networks [PDF]

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   +2 more sources

Brane cosmology from observational surveys and its comparison with standard FRW cosmology [PDF]

, 2013
Several dark energy models on the brane are investigated. They are compared with corresponding theories in the frame of 4d Friedmann-Robertson-Walker cosmology.
Artyom V. Astashenok, Emilio Elizalde, Jaume de Haro, Sergei D. Odintsov, Artyom V. Yurov, Artyom V. Astashenok, Emilio Elizalde, Jaume de Haro, Sergei D. Odintsov, Artyom V. Yurov   +9 more
openalex   +3 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

Observational constraints on the fractal cosmology

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   +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

Observational effects from quantum cosmology [PDF]

, 2013
The status of quantum cosmologies as testable models of the early universe is assessed in the context of inflation. While traditional Wheeler-DeWitt quantization is unable to produce sizable effects in the cosmic microwave background, the more recent ...
Calcagni, Gianluca
core   +3 more sources

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

Dark Matter and Galaxy Formation: Challenges for the Next Decade [PDF]

, 2004
The origin of the galaxies represents an important focus of current cosmological research, both observational and theoretical. Its resolution involves a comprehensive understanding of star formation, galaxy dynamics, the cosmology of the very early ...
Silk, Joseph
core   +3 more sources