Results 51 to 60 of about 103,703 (233)

Beyond No No Tension: JWST z > 10 Galaxies Push Simulations to the Limit

open access: yesThe Open Journal of Astrophysics
JWST has identified some of the Universe's earliest galaxies, repeatedly pushing the frontier to ever higher redshifts and stellar masses. The presence of such extreme galaxies at such early times, with large stellar populations and high star-formation ...
Joe McCaffrey   +3 more
doaj   +1 more source

Two Micron‐Size Dark Dimensions

open access: yesFortschritte 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

Nihao XIII: Clumpy discs or clumpy light in high-redshift galaxies? [PDF]

open access: yes, 2016
Many massive star forming disc galaxies in the redshift range 3 to 0.5 are observed to have a clumpy morphology showing giant clumps of size $\sim$1 kpc and masses of about $10^{7}M_{\odot}$ to $10^{10} M_{\odot}$.
T. Buck   +8 more
semanticscholar   +1 more source

An Empirical Consistent Redshift Bias: A Possible Direct Observation of Zwicky’s TL Theory

open access: yesParticles
Recent advancements have shown tensions between observations and our current understanding of the Universe. Such observations may include the H0 tension and massive galaxies at high redshift that are older than traditional galaxy formation models have ...
Lior Shamir
doaj   +1 more source

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

open access: yesAstronomische 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

First Light: exploring the Spectra of High-Redshift Galaxies in the Renaissance Simulations [PDF]

open access: yes, 2017
We present synthetic observations for the first generations of galaxies in the Universe and make predictions for future deep field observations for redshifts greater than 6.
Kirk S. S. Barrow   +4 more
semanticscholar   +1 more source

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

open access: yesComputer 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   +3 more
wiley   +1 more source

The infrared-dark dust content of high redshift galaxies [PDF]

open access: yes, 2016
We present a theoretical model aimed at explaining the IRX-$\beta$ relation for high redshift (z >5) galaxies. Recent observations (Capak+2015; Bouwens+2016) have shown that early Lyman Break Galaxies, although characterized by a large UV attenuation (e ...
A. Ferrara   +3 more
semanticscholar   +1 more source

First Detection of CO Isotopologues in a High-redshift Main-sequence Galaxy: Evidence of a Top-heavy Stellar Initial Mass Function

open access: yesThe Astrophysical Journal
Recent observations and theories have presented a strong challenge to the universality of the stellar initial mass function (IMF) in extreme environments. A notable example has been found for starburst conditions, where evidence favors a top-heavy IMF, i.
Ziyi Guo   +7 more
doaj   +1 more source

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