Results 51 to 60 of about 738 (163)

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

Fast Transients at Cosmological Distances with the SKA [PDF]

, 2015
Impulsive radio bursts that are detectable across cosmological distances constitute extremely powerful probes of the ionized Inter-Galactic Medium (IGM), intergalactic magnetic fields, and the properties of space-time itself.
Rene Breton, Trott, Laura Spitler, Deller, A, Grainge, K., Cathryn Trott, Lorimer, D., Deller, A., Eran Oded Ofek, Hessels, J, Chatterjee, S, Duncan Lorimer, Lorimer, D, Stappers, B; id_orcid, McQuinn, M., Ben Stappers, Fender, R., Ramesh Bhat, Shami Chatterjee, Pietka, M, Law, C, Spitler, L., Grainge, Keith, Casey Law, Bhat, Ramesh, Trott, C, Macquart, J P, McQuinn, M, Bhat, R., Jean -Pierre Macquart, Evan Keane, Fender, R, Ofek, E O, Law, C., Stappers, B., Macquart, Jean-Pierre, Breton, R., Ofek, E., Hessels, J., Macquart, J., Trott, Cathryn, Keane, E, Keane, E., Pietka, M., Chatterjee, S., Malgorzata Pietka, Matthew McQuinn, Bhat, R, Breton, Rene; id_orcid, Spitler, L, K. Grainge, Adam Deller, Rob Fender, Jason Hessels   +53 more
core   +3 more sources

Lactea: Web‐Based Spectrum‐Preserving Multi‐Resolution Visualization of the GAIA Star Catalog

Computer Graphics Forum, Volume 44, Issue 3, June 2025.
Abstract The explosion of data in astronomy has resulted in an era of unprecedented opportunities for discovery. The GAIA mission's catalog, containing a large number of light sources (mostly stars) with several parameters such as sky position and proper motion, is playing a significant role in advancing astronomy research and has been crucial in ...
Reem Alghamdi, Markus Hadwiger, Guido Reina, Alberto Jaspe‐Villanueva   +3 more
wiley   +1 more source

The Lens Parallax Method: Determining Redshifts of Faint Blue Galaxies through Gravitational Lensing

, 2019
We propose a new technique, which we call the lens parallax method, to determine simultaneously the redshift distribution of the faint blue galaxies and the mass distributions of foreground clusters of galaxies.
Narayan, Ramesh, Bartelmann, Matthias
core   +1 more source

swPHoToNs: Toward trillion‐body‐scale cosmological N‐body simulations on Sunway TaihuLight supercomputer

Engineering Reports, Volume 7, Issue 3, March 2025.
We present the details of implementing a highly efficient and scalable Cosmological N‐body simulation framework on the heterogeneous many‐core supercomputer Sunway TaihuLight. We manage to conduct cosmological simulations which contain up to 1.6 trillion particles, obtaining a sustained performance of 56.3 PFlops with a weak‐scaling parallel efficiency
Zhao Liu, Qiao Wang, Xiaojing Lv, Xu Liu, Hongsong Meng, Guanghui Zhu, Liang Gao, Haohuan Fu, Guangwen Yang   +8 more
wiley   +1 more source

Investigating the redshift evolution of lensing galaxy density slopes via model-independent distance ratios

Astronomy & Astrophysics
Context. Strong-lensing systems are expected to be discovered in great numbers by next-generation surveys. They provide a powerful tool for studying cosmology and the galaxy evolution. The coupling of the galaxy structure and cosmology through distance ratios means that it is essential for advancing both fields to examine the evolution of the lensing ...
S. Geng, M. Grespan, H. Thuruthipilly, S. Harikumar, A. Pollo, M. Biesiada   +5 more
openaire   +2 more sources

Determination of the Cosmic Distance Scale from Sunyaev‐Zel’dovich Effect andChandraX‐Ray Measurements of High‐Redshift Galaxy Clusters

The Astrophysical Journal, 2006
ApJ submitted (revised version)
Bonamente, M., Joy, M., La Roque, S., Carlstrom, J., Reese, E., Dawson, K.   +5 more
openaire   +2 more sources

Searching the Non‐Accreting White Dwarf Population in eROSITA Data

Astronomische Nachrichten, Volume 346, Issue 1, January 2025.
ABSTRACT eROSITA is the soft X‐ray instrument aboard the Spectrum Roentgen Gamma (SRG) satellite that is most sensitive in the energy range between 0.2 and 2.3 keV. Between December 2019 and December 2021, eROSITA completed four all‐sky surveys, producing all‐sky X‐ray source lists and sky maps of unprecedented depth.
S. Friedrich, C. Maitra, K. Dennerl, A. Schwope, K. Werner, B. Stelzer   +5 more
wiley   +1 more source

Probing extreme black‐hole outflows on short timescales via high spectral‐resolution x‐ray imagers

Astronomische Nachrichten, Volume 345, Issue 6-7, July-August 2024.
Abstract We investigate outflows and the physics of super‐Eddington versus sub‐Eddington regimes in black hole systems. Our focus is on prospective science using next‐generation high‐resolution soft x‐ray instruments. We highlight the properties of black hole ultraluminous x‐ray source (ULX) systems in particular. Owing to scale invariance in accreting
C. Pinto, J. F. Steiner, A. Bodaghee, P. Chakraborty, M. Sobolewska, D. R. Pasham, A. Ogorzalek, J. Zuhone, A. Bogdan, M. Vogelsberger   +9 more
wiley   +1 more source

The scaling relation of early-type galaxies in clusters II. Spectroscopic data for galaxies in eight nearby clusters

, 2006
Galaxies: elliptical and lenticulars, cD, distances and redshifts - clusters: general Udgivelsesdato ...
D. Bettoni, P. Kjærgaard, Moles, M., Varela, J., Rasmussen, Per Kjærgaard, Fasano, G., Bettoni, D., G. Fasano, M. Moles, J. Varela   +9 more
core   +1 more source