Results 61 to 70 of about 87,875 (159)

Enhancing weak lensing redshift distribution characterization by optimizing the Dark Energy Survey Self-Organizing Map Photo-z method

The Open Journal of Astrophysics
Characterization of the redshift distribution of ensembles of galaxies is pivotal for large scale structure cosmological studies. In this work, we focus on improving the Self-Organizing Map (SOM) methodology for photometric redshift estimation (SOMPZ ...
A. Campos, B. Yin, S. Dodelson, A. Amon, A. Alarcon, C. Sánchez, G. M. Bernstein, G. Giannini, J. Myles, S. Samuroff, O. Alves, F. Andrade-Oliveira, K. Bechtol, M. R. Becker, J. Blazek, H. Camacho, A. Carnero Rosell, M. Carrasco Kind, R. Cawthon, C. Chang, R. Chen, A. Choi, J. Cordero, C. Davis, J. DeRose, H. T. Diehl, C. Doux, A. Drlica-Wagner, K. Eckert, T. F. Eifler, J. Elvin-Poole, S. Everett, X. Fang, A. Ferté, O. Friedrich, M. Gatti, D. Gruen, R. A. Gruendl, I. Harrison, W. G. Hartley, K. Herner, H. Huang, E. M. Huff, M. Jarvis, E. Krause, N. Kuropatkin, P. -F. Leget, N. MacCrann, J. McCullough, A. Navarro-Alsina, S. Pandey, J. Prat, M. Raveri, R. P. Rollins, A. Roodman, R. Rosenfeld, A. J. Ross, E. S. Rykoff, J. Sanchez, L. F. Secco, I. Sevilla-Noarbe, E. Sheldon, T. Shin, M. A. Troxel, I. Tutusaus, T. N. Varga, R. H. Wechsler, B. Yanny, Y. Zhang, J. Zuntz, M. Aguena, J. Annis, D. Bacon, S. Bocquet, D. Brooks, D. L. Burke, J. Carretero, F. J. Castander, M. Costanzi, L. N. da Costa, J. De Vicente, P. Doel, I. Ferrero, B. Flaugher, J. Frieman, J. García-Bellido, E. Gaztanaga, G. Gutierrez, S. R. Hinton, D. L. Hollowood, K. Honscheid, D. J. James, K. Kuehn, M. Lima, H. Lin, J. L. Marshall, J. Mena-Fernández, F. Menanteau, R. Miquel, R. L. C. Ogando, M. Paterno, M. E. S. Pereira, A. Pieres, A. A. Plazas Malagón, A. Porredon, E. Sanchez, D. Sanchez Cid, M. Smith, E. Suchyta, M. E. C. Swanson, G. Tarle, C. To, V. Vikram, N. Weaverdyck   +113 more
doaj   +1 more source

The statistical lensing of QSOs [PDF]

, 2003
We use the 2dF QSO Redshift Survey, to investigate whether QSOs are detectably gravitationally lensed. Lensing could magnify and distort light from QSOs, influencing QSO numbers near galaxies, which trace structure in our Universe. Following Boyle, Fong &
Myers, Adam David
core  

Observations Favor the Redshift-evolutionary L X–L UV Relation of Quasars from Copula

The Astrophysical Journal
We compare, with data from quasars, Hubble parameter measurements, and Pantheon+ type Ia supernova, three different relations between X-ray luminosity ( L _X ) and ultraviolet luminosity ( L _UV ) of quasars. These three relations consist of the standard
Bao Wang, Yang Liu, Hongwei Yu, Puxun Wu
doaj   +1 more source

Mapping the dynamics, star-formation rates, and chemical properties of galaxies with integral field spectroscopy [PDF]

, 2005
Major advances in the development of instruments for eight and ten meter class telescopes are revolutionising our understanding of galaxy formation. In particular, Integral Field Spectrographs (which produce a three dimensional {x, y, velocity) map of a ...
Swinbank, Anthony Mark, Swinback, Anthony Mark   +1 more
core  

Redshift Evolution of the X-Ray and Ultraviolet Luminosity Relation of Quasars: Calibrated Results from SNe Ia

The Astrophysical Journal
Quasars could serve as standard candles if the relation between their ultraviolet (UV) and X-ray luminosities can be accurately calibrated. Previously, we developed a model-independent method to calibrate quasar standard candles using the distance ...
Xiaolei Li, Ryan E. Keeley, Arman Shafieloo   +2 more
doaj   +1 more source

Machine Learning–based Search of High-redshift Quasars

The Astrophysical Journal Supplement Series
We present a machine learning search for high-redshift (5.0 < z < 6.5) quasars using the combined photometric data from the Dark Energy Spectroscopic Instrument (DESI) Imaging Legacy Surveys and the Wide-field Infrared Survey Explorer survey.
Guangping Ye, Huanian Zhang, Qingwen Wu
doaj   +1 more source

Leveraging Redshift Probabilities and Machine Learning Classification to Identify Catastrophic Outlier Photometric Redshift Estimates

The Astrophysical Journal
We present results of using a basic binary classification neural network model to identify likely catastrophic outlier (CO) photometric redshift estimates of individual galaxies.
J. Yoo, C. Gyure, V. Agarwal, J. Singal, G. Silverman   +4 more
doaj   +1 more source

Generalized redshift formula through an energy-based framework

Scientific Reports
Redshift is a crucial concept in physics; it has significant implications for our understanding of the dynamics and evolution of the cosmos. In this article, we introduce a generalized formula to determine the redshift parameter.
C. Ortiz, F. Ibarra-Castor
doaj   +1 more source

The clustering of dark matter, haloes & galaxies [PDF]

, 2008
In this thesis I study the spatial distribution of galaxies, haloes and dark matter particles using a suite of state-of-art cosmological N-body simulations of the growth structure in the Universe.
Angulo de la Fuente, Raúl Esteban
core  

Detection of gamma-ray burst Amati relation based on Hubble data set and Pantheon+ samples

European Physical Journal C: Particles and Fields
Using gamma-ray bursts as standard candles for cosmological parameter constraints rely on their empirical luminosity relations and low-redshift calibration.
Yufen Han, Jiaze Gao, Gang Liu, Lixin Xu
doaj   +1 more source