Results 81 to 90 of about 47,826 (245)

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

Targeting cluster galaxies for the 4MOST CHANCES Low-z sub-survey with photometric redshifts

Astronomy & Astrophysics
Context. The evolution of galaxies is shaped by both internal processes and their external environments. Galaxy clusters and their surroundings provide ideal laboratories to study these effects, particularly with respect to mechanisms such as quenching ...
Méndez-Hernández Hugo, Lima-Dias Ciria, Monachesi Antonela, Jaffé Yara L., Haines Christopher P., Teixeira Gabriel S. M., Lösch Elismar, Baier-Soto Raúl, Lima Erik V. R., Amrutha B. M., Bom C. R., D’Ago Giuseppe, Demarco Ricardo, Finoguenov Alexis, Haack Rodrigo F., Lopes Amanda R., de Oliveira C. Mendes, Merluzzi Paola, Piraino-Cerda Franco, Smith Castelli Analía V., Sifón Cristobal, Sodré Laerte, Tejos Nicolás, Torres-Flores Sergio, Argudo-Fernández Maria, Crossett Jacob P., Ibar E., Kuchner Ulrike, Lacerna Ivan, Lopes-Silva Vitor H., Lopez Sebastián, McGee Sean, Morelli Lorenzo, Nantais Julie, Olivares V. Patricio, Pallero Diego, Poggianti Bianca M., Pompei Emanuela, Sampaio V. M., Vulcani Benedetta, Zenteno Alfredo, Almeida-Fernandes F., Bilicki Maciej, Carvalho M. S., Cheng Cheng, Figueiredo A. L.,, Gutiérrez-Soto L. A., Herpich F. R., Kanaan A., Lacerda E A. D., Nakazono L., Oliveira Schwarz G. B., Ribeiro T., Roukema Boudewijn F., Sartori Marília J., Santos-Silva Thaís, Schoenell W.   +56 more
doaj   +1 more source

Pure Spectroscopic Constraints on UV Luminosity Functions and Cosmic Star Formation History from 25 Galaxies at z spec = 8.61–13.20 Confirmed with JWST/NIRSpec

The Astrophysical Journal, 2023
We present pure spectroscopic constraints on the UV luminosity functions and cosmic star formation rate (SFR) densities from 25 galaxies at z _spec = 8.61–13.20. By reducing the JWST/NIRSpec spectra taken in multiple programs of Early Release Observation,
Yuichi Harikane, Kimihiko Nakajima, Masami Ouchi, Hiroya Umeda, Yuki Isobe, Yoshiaki Ono, Yi Xu, Yechi Zhang   +7 more
doaj   +1 more source

Spectroscopic identification of a redshift 1.55 supernova host galaxy from the Subaru Deep Field Supernova Survey [PDF]

, 2014
Context: The Subaru Deep Field (SDF) Supernova Survey discovered 10 Type Ia supernovae (SNe Ia) in the redshift range 1 ...
Frederiksen, Teddy F., Graur, Or, Hjorth, Jens, Maoz, Dan, Poznanski, Dovi   +4 more
core   +1 more source

The Compilation and Validation of the Spectroscopic Redshift Catalogs for the DESI-COSMOS and DESI-XMM-LSS Fields

The Astronomical Journal
Over several dedicated programs that include targets beyond the main cosmological samples, the Dark Energy Spectroscopic Instrument collected spectra for 304,970 unique objects in two fields centered on the COSMOS and XMM-LSS fields.
J. Ratajczak, K. S. Dawson, N. Weaverdyck, J. Aguilar, S. Ahlen, E. Armengaud, S. Bailey, D. Bianchi, D. Blanco, A. Brodzeller, D. Brooks, F. J. Castander, T. Claybaugh, A. Cuceu, A. de la Macorra, Arjun Dey, Biprateep Dey, P. Doel, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, S. Gontcho A Gontcho, G. Gutierrez, J. Guy, T. Hagen, H. K. Herrera-Alcantar, K. Honscheid, D. Huterer, M. Ishak, J. Jimenez, R. Joyce, S. Juneau, R. Kehoe, D. Kirkby, T. Kisner, S. E. Koposov, A. Kremin, O. Lahav, A. Lambert, C. Lamman, M. Landriau, L. Le Guillou, A. Leauthaud, J. Lee, M. E. Levi, Q. Li, I. Longhurst, Y. Luo, M. Manera, P. Martini, J. McCullough, A. Meisner, R. Miquel, J. Moustakas, S. Nadathur, J. A. Newman, N. Palanque-Delabrouille, W. J. Percival, C. Poppett, F. Prada, I. Pérez-Ràfols, A. Raichoor, C. Ravoux, G. Rossi, Y. Salcedo Hernandez, E. Sanchez, C. Saulder, D. Schlegel, M. Schubnell, H. Seo, D. Sprayberry, G. Tarlé, B. A. Weaver, R. H. Wechsler, M. White, R. Zhou, H. Zou   +76 more
doaj   +1 more source

Understanding Volatile Electrical Switching in hBN Nanodevices by Fully Optical Operando Investigation

Small, Volume 21, Issue 26, July 3, 2025.
Operando optical characterization of vertical two‐terminal monolayer hexagonal Boron Nitride devices is used to gain new insight into the key role of defects in the dynamics of switching. Characterization of photoluminescence and dark‐field scattering light signals during electrical switching indicates that the formation of conductive filaments of gold
Dawn M. Kelly, Joanna Symonowicz, J. Callum Stewart, Stephan Hofmann, Giuliana Di Martino   +4 more
wiley   +1 more source

Superphot+: Real-time Fitting and Classification of Supernova Light Curves

The Astrophysical Journal
Photometric classifications of supernova (SN) light curves have become necessary to utilize the full potential of large samples of observations obtained from wide-field photometric surveys, such as the Zwicky Transient Facility (ZTF) and the Vera C ...
Kaylee M. de Soto, V. Ashley Villar, Edo Berger, Sebastian Gomez, Griffin Hosseinzadeh, Doug Branton, Sandro Campos, Melissa DeLucchi, Jeremy Kubica, Olivia Lynn, Konstantin Malanchev, Alex I. Malz   +11 more
doaj   +1 more source

On the use of photometric redshifts for X-ray selected AGNs

, 2004
(Abridged) In this paper we present photometric redshift estimates for a sample of X-ray selected sources detected in the wide field (~2 deg^2), bright [f_{X} (0.5-8 keV)~10^{-14} cgs] XMM-Newton/2dF survey. Unlike deeper X-ray samples comprising a large
A. Georgakakis, Babbedge, Barcons, Barger, Brandt, Brandt, Budavári, Budavári, Coleman, Croom, Csabai, Downes, E. Hatziminaoglou, Fukugita, Georgakakis, Georgakakis, Georgantopoulos, Georgantopoulos, Giacconi, Gonzalez, Green, Hasinger, Hatziminaoglou, Hatziminaoglou, I. Georgantopoulos, Kim, Kim, Madau, Mainieri, Mobasher, Pickles, Richards, Richards, S. Kitsionas, Stocke, Stoughton, Wang, York   +37 more
core   +1 more source

On estimating redshift and luminosity distributions in photometric redshift surveys [PDF]

, 2007
The luminosity functions of galaxies and quasars provide invaluable information about galaxy and quasar formation. Estimating the luminosity function from magnitude limited samples is relatively straightforward, provided that the distances to the objects
Sheth, Ravi K.
core   +3 more sources

Redshift‐Agnostic Machine Learning Classification: Unveiling Peak Performance in Galaxy, Star, and Quasar Classification (Using SDSS DR17)

Astronomische Nachrichten, Volume 346, Issue 5, June 2025.
ABSTRACT Classification of galaxies, stars, and quasars using spectral data is fundamental to astronomy, but often relies heavily on redshift. This study evaluates the performance of 10 machine learning algorithms on SDSS data to classify these objects, with a particular focus on scenarios where redshift information is unavailable.
Debashis Chatterjee, Prithwish Ghosh
wiley   +1 more source