Results 121 to 130 of about 532,071 (203)

Accuracy Assessment of Thematic Maps Using Inter-Class Spectral Distances

open access: yes, 2002
The goal of this research is to develop a new approach to remote sensing thematic accuracy assessment in which the spectral distances between the classes in a thematic classification are used as inputs to the error estimation process.
Knight, Joseph
core  

SN 2024aecx: A Fast-evolving Type IIb Supernova with a Prominent Shock-cooling Peak

open access: yesThe Astrophysical Journal
SN 2024aecx is a nearby (∼11 Mpc) Type IIb SN discovered within ∼1 day after explosion. In this paper we report high-cadence photometric (typically 0.5 ∼ 1 day) and spectroscopic follow-up observations, conducted from as early as 0.27 day post discovery ...
Qiang Xi   +38 more
doaj   +1 more source

The Crystal Structures of High‐ and Low‐Temperature Silver Pyrophosphate: Structural Instability and Its Consequences

open access: yesZeitschrift für anorganische und allgemeine Chemie, Volume 652, Issue 15, 1 October 2026.
The crystal structures of the high‐temperature and low‐temperature phases of silver pyrophosphate are reported. The structural results are complemented by thermal analysis, vibrational and 31P‐MAS‐NMR spectroscopy studies, and density functional theory calculations.
Matthias Weil   +8 more
wiley   +1 more source

Broad line emission from iron K- and L-shell transitions in the active galaxy 1H 0707-495

open access: yes, 2009
Since the 1995 discovery of the broad iron K-line emission from the Seyfert galaxy MCG-6-30-15 (ref. 1), broad iron K lines have been found in emission from several other Seyfert galaxies, from accreting stellar-mass black holes and even from accreting ...
T. Boller   +70 more
core   +1 more source

FAST Ultra-Deep Survey: The Baryonic Tully–Fisher Relation in FUDS0 Field

open access: yesThe Astrophysical Journal
The baryonic Tully–Fisher relation (BTFR) is one of the tightest scaling relations for disk galaxies in the local Universe, and therefore is an important tool for studying the fomation and evolution of galaxies.
Hongwei Xi   +6 more
doaj   +1 more source

A 400‐Year Antarctic Ice‐Core Perchlorate Record Reveals Variability in Stratospheric Chlorine Chemistry

open access: yesGeophysical Research Letters, Volume 53, Issue 18, 28 September 2026.
Abstract Perchlorate (ClO4−) in polar ice preserves past chlorine oxidation chemistry; however, multi‐centennial Antarctic ClO4− records and the mechanisms controlling their variability remain poorly constrained. Here, we present the first 400‐year (1616−2016) ClO4− record from an Antarctic ice core, revealing two regimes separated around 1980.
Wenzhi Zhou   +6 more
wiley   +1 more source

Galaxy groups in the presence of cosmological constant: Increasing the masses of groups

open access: yesPhysics Letters B
The boundaries of galaxy groups and clusters are defined by the interplay between the Newtonian attractive force and the decoupling from the local expansion of the Universe.
David Benisty   +2 more
doaj   +1 more source

A machian model as potential alternative to dark matter halo thesis in galactic rotational velocity prediction

open access: yesFrontiers in Astronomy and Space Sciences
A novel axially symmetric metric is proposed to solve the Einstein field equations. This provides an analytical solution within the matter in the equatorial plane for any galaxy density profile.
Stephan Walrand
doaj   +1 more source

Tip of the Red Giant Branch Distances with JWST: An Absolute Calibration in NGC 4258 and First Applications to Type Ia Supernova Hosts

open access: yesThe Astrophysical Journal
The tip of the red giant branch (TRGB) allows for the measurement of precise and accurate distances to nearby galaxies based on the brightest ascent of low-mass red giant branch stars before they undergo the helium flash.
Gagandeep S. Anand   +14 more
doaj   +1 more source

bgruening/docker-galaxy-imaging: 18.01 release

open access: yes, 2018
:whale: Galaxy Docker repository with Imaging tools (Galaxy Imaging ...
ThomasWollmann   +2 more
core   +1 more source

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