Results 61 to 70 of about 15,250,094 (223)
Spectroscopic Confirmation of a Massive Protocluster with Two Substructures at z ≃ 3.1
The Astrophysical JournalWe present the results of a Keck and Northern Extended Millimeter Array spectroscopic survey of 507 galaxies, where we confirm the presence of two massive overdensities at z = 3.090−3.110 and z = 3.133−3.155 in the neighborhood of the GOODS-N, each with ...
Michael J. Nicandro Rosenthal +5 more
doaj +1 more source
Dynamical Dark Sector: A Joint Two‐Scalar‐Field Model for Dark Matter and Quintessence
Advances in Astronomy, Volume 2026, Issue 1, 2026.The physical nature of dark matter and dark energy remains one of the most pressing questions in modern cosmology. This work presents a phenomenological model where the entire dark sector is described by two minimally coupled scalar fields within general relativity.
Silvio A. Corrêa Junior, Jianguo Yan
wiley +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 +1 more
core
ChemPhysChem, Volume 26, Issue 18, September 19, 2025.In bulk carbonic acid (e.g., in interstellar icy dust grains) cluster formation produces two distinct UV‐Vis spectral features redshifted by ≈2 eV (25 nm) and by ≈5 eV (80 nm) compared to gas phase single molecule carbonic acid 's adiabatic ionization energy. Theory and experiment were used to investigate the origin of these shifts.
Dennis F. Dinu +7 more
wiley +1 more source
Constraining dark energy using real and mock galaxy surveys [PDF]
, 2009 In this thesis, we study how dark energy may be constrained by measurements of large-scale clustering in future galaxy surveys, and through the imprint of a time-varying large-scale potential on the CMB (the integrated Sachs-Wolfe effect).
CAI, YANCHUAN
core
MAGAZ3NE: Evidence for Galactic Conformity in z ≳ 3 Protoclusters
The Astrophysical JournalWe examine the quiescent fractions of massive galaxies in six z ≳ 3 spectroscopically confirmed protoclusters in the COSMOS field, one of which is newly confirmed and presented here. We report the spectroscopic confirmation of MAGAZ3NE J100143+023021 at $
Ian McConachie +18 more
doaj +1 more source
Weak lensing by high-redshift clusters of galaxies [PDF]
Astronomy & Astrophysics, 2003 We use weak lensing shear measurements of six z>0.5 clusters of galaxies to derive the mean lensing redshift of the background galaxies used to measure the shear.
Clowe, D., Luppino, G., Kaiser, N.
openaire +2 more sources
Two Micron‐Size Dark Dimensions
Fortschritte der Physik, Volume 73, Issue 8, August 2025.Abstract Two extra dimensions of micron scale might simultaneously address the gauge and cosmological hierarchy problems. In this paper various observational bounds in scenarios with one and two large extra dimensions are examined, to see if they are compatible with the micron scale.
Luis A. Anchordoqui +2 more
wiley +1 more source
The Astrophysical JournalWe present an analysis of the number density of galaxies as a function of stellar mass (i.e., the stellar mass function (SMF)) in the COSMOS field at z ∼ 3.3, making a comparison between the SMF in overdense environments and the SMF in the coeval field ...
Ben Forrest +19 more
doaj +1 more source
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