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Multivariate Approaches to Classification in Extragalactic Astronomy [PDF]

open access: yesFrontiers in Astronomy and Space Sciences, 2015
Clustering objects into synthetic groups is a natural activity of any science. Astrophysics is not an exception and is now facing a deluge of data. For galaxies, the one-century old Hubble classification and the Hubble tuning fork are still largely in ...
Didier eFraix-Burnet   +3 more
doaj   +8 more sources

The Long-Term Future of Extragalactic Astronomy [PDF]

open access: yesPhysical Review D, 2001
If the current energy density of the universe is indeed dominated by a cosmological constant, then high-redshift sources will remain visible to us only until they reach some finite age in their rest-frame. The radiation emitted beyond that age will never
A. Riess   +22 more
core   +7 more sources

How Are Red and Blue Quasars Different? The Radio Properties

open access: yesGalaxies, 2021
A non-negligible fraction of quasars are red at optical wavelengths, indicating (in the majority of cases) that the accretion disc is obscured by a column of dust which extinguishes the shorter-wavelength blue emission. In this paper, we summarize recent
Victoria A. Fawcett   +3 more
doaj   +1 more source

Discovery of an Isolated Dark Dwarf Galaxy in the Nearby Universe

open access: yesThe Astrophysical Journal Letters, 2023
Based on a new H i survey using the Five-hundred-meter Aperture Spherical radio Telescope (FAST), combined with the Pan-STARRS1 images, we identified an isolated H i cloud without any optical counterpart, named FAST J0139+4328.
Jin-Long Xu   +6 more
doaj   +1 more source

The Event Horizon Telescope Image of the Quasar NRAO 530

open access: yesThe Astrophysical Journal, 2023
We report on the observations of the quasar NRAO 530 with the Event Horizon Telescope (EHT) on 2017 April 5−7, when NRAO 530 was used as a calibrator for the EHT observations of Sagittarius A*.
Svetlana Jorstad   +269 more
doaj   +1 more source

The Connection between the Intracluster Light and its Host Halo: Formation Time and Contribution from Different Channels

open access: yesThe Astronomical Journal, 2023
We extend the analysis presented by Contini et al. to higher redshifts, up to z = 2, by focusing on the relation between the intracluster light (ICL) fraction and the halo mass, its dependence on redshift, the role played by the halo concentration, and ...
Emanuele Contini   +4 more
doaj   +1 more source

Astronomy with energy dependent flavour ratios of extragalactic neutrinos

open access: yesJournal of High Energy Physics, 2021
High energy astrophysical neutrinos interacting with ultralight dark matter (DM) can undergo flavour oscillations that induce an energy dependence in the flavour ratios.
Siddhartha Karmakar   +2 more
doaj   +1 more source

REQUIEM-2D: A Diversity of Formation Pathways in a Sample of Spatially Resolved Massive Quiescent Galaxies at z ∼ 2

open access: yesThe Astrophysical Journal, 2023
REQUIEM-2D (Resolving Quiescent Magnified Galaxies with 2D Grism Spectroscopy) comprises a sample of eight massive ( ${\rm{log}}({M}_{\ast }/{M}_{\odot })\gt 10.6$ ) strongly lensed quiescent galaxies at z ∼ 2.
Mohammad Akhshik   +18 more
doaj   +1 more source

Extragalactic Astronomy at Arcetri

open access: yesIl Colle di Galileo, 2023
Extragalactic science was introduced at the Arcetri Observatory towards the end of the 1970’s, upon the arrival of a new director, Franco Pacini. The first dedicated line of research emerged in collaboration with Cornell University and the study of neutral hydrogen.
Filippo Mannucci   +2 more
openaire   +1 more source

History of Astronomy in Australia: Big-Impact Astronomy from World War II until the Lunar Landing (1945–1969)

open access: yesGalaxies, 2021
Radio astronomy commenced in earnest after World War II, with Australia keenly engaged through the Council for Scientific and Industrial Research. At this juncture, Australia’s Commonwealth Solar Observatory expanded its portfolio from primarily studying
Alister W. Graham   +4 more
doaj   +1 more source

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