Results 71 to 80 of about 679,095 (339)
Light Elements in the Universe
Frontiers in Astronomy and Space Sciences, 2021 Due to their production sites, as well as to how they are processed and destroyed in stars, the light elements are excellent tools to investigate a number of crucial issues in modern astrophysics: from stellar structure and non-standard processes at work
Sofia Randich, Laura Magrini
doaj +1 more source
The clustering of the SDSS DR7 Main Galaxy Sample I: a 4 per cent distance measure at z=0.15 [PDF]
, 2014 We create a sample of spectroscopically identified galaxies with z < 0.2 from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7), covering 6813 deg(2).
A. Ross +5 more
semanticscholar +1 more source
Anisotropic Galaxy-Galaxy Lensing
, 2000 We investigate the weak lensing shear due to dark matter galaxy halos whose mass distributions, as projected on the sky, are nearly elliptical. The shear pattern due to these halos is anisotropic about the lens centers and we quantify the level of anisotropy by comparing the mean shear experienced by sources located closest to the major axes of the ...
Brainerd, T. G., Wright, C. O.
openaire +2 more sources
The Astronomical Journal, 2012 A growing number of low luminosity and low surface brightness astronomical objects challenge traditional notions of both galaxies and star clusters. To address this, we propose a definition of galaxy independent of the cold dark matter model of the universe: A galaxy is a gravitationally bound set of stars whose properties cannot be explained by a ...
Willman, Beth, Strader, Jay
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Joint galaxy–galaxy lensing and clustering constraints on galaxy formation [PDF]
Monthly Notices of the Royal Astronomical Society, 2020 ABSTRACT We compare predictions for galaxy–galaxy lensing profiles and clustering from the Henriques et al. public version of the Munich semi-analytical model (SAM) of galaxy formation and the IllustrisTNG suite, primarily TNG300, with observations from KiDS + GAMA and SDSS-DR7 using four different selection functions for the lenses ...
Malin Renneby +7 more
openaire +4 more sources
Breaking the hierarchy of galaxy formation [PDF]
, 2005 Recent observations of the distant Universe suggest that much of the stellar mass of bright galaxies was already in place at z > 1. This presents a challenge for models of galaxy formation because massive halos are assembled late in the hierarchical ...
R. Bower +10 more
semanticscholar +1 more source
First results from the IllustrisTNG simulations: the galaxy colour bimodality [PDF]
, 2017 We introduce the first two simulations of the IllustrisTNG project, a next generation of cosmological magnetohydrodynamical simulations, focusing on the optical colors of galaxies.
D. Nelson +11 more
semanticscholar +1 more source
DETAILED DECOMPOSITION OF GALAXY IMAGES. II. BEYOND AXISYMMETRIC MODELS [PDF]
, 2009 We present a two-dimensional (2D) fitting algorithm (Galfit, ver. 3) with new capabilities to study the structural components of galaxies and other astronomical objects in digital images.
C. Peng, L. Ho, C. Impey, H. Rix
semanticscholar +1 more source
Advanced Materials, EarlyView.A fully flexible ion‐gel‐gated graphene‐channel transistor driven by a triboelectric nanogenerator enables self‐powered tactile sensing and synaptic learning. Mimicking spike‐rate‐dependent plasticity, the device exhibits frequency‐selective potentiation and depression, supporting rate‐coded neuromorphic computation even under flex.
Hanseong Cho +3 more
wiley +1 more source
Symposium - International Astronomical Union, 1987 Theories of galaxy formation via hierarchical clustering of cold dark matter and by fragmentation of gaseous pancakes or shells are reviewed and compared. Dissipative processes are crucial to all theories of galaxy formation, and are discussed in terms of a simple model involving multiple cloud interactions.
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