Results 51 to 60 of about 53,761 (176)

Antimatter Gravity and the Results of the ALPHA‐g Experiment

Annalen der Physik, Volume 536, Issue 7, July 2024.
The recent results of the ALPHA‐g experiment, which show gravitational attraction between antihydrogen atoms and the Earth, seem to undermine the success of repulsive‐gravity models in the cosmological field. Analyzing the theory of CPT gravity, two solutions are found that are consistent with the experimental results, while preserving the large‐scale ...
Massimo Villata
wiley   +1 more source

Daris, a low-frequency distributed aperture array for radio astronomy in space [PDF]

, 2010
DARIS (Distributed Aperture Array for Radio Astronomy in Space) is a radio astronomy space mission concept aimed at observing the low-frequency radio sky in the range 1-10 MHz.
Bentum, M.J., Boonstra, A.J., Falcke, H., Klooster, K. van 't, Saks, N.   +4 more
core   +1 more source

Probing extreme black‐hole outflows on short timescales via high spectral‐resolution x‐ray imagers

Astronomische Nachrichten, Volume 345, Issue 6-7, July-August 2024.
Abstract We investigate outflows and the physics of super‐Eddington versus sub‐Eddington regimes in black hole systems. Our focus is on prospective science using next‐generation high‐resolution soft x‐ray instruments. We highlight the properties of black hole ultraluminous x‐ray source (ULX) systems in particular. Owing to scale invariance in accreting
C. Pinto, J. F. Steiner, A. Bodaghee, P. Chakraborty, M. Sobolewska, D. R. Pasham, A. Ogorzalek, J. Zuhone, A. Bogdan, M. Vogelsberger   +9 more
wiley   +1 more source

JWST imaging of the closest globular clusters—I. Possible infrared excess among white dwarfs in NGC 6397

Astronomische Nachrichten, Volume 345, Issue 6-7, July-August 2024.
Abstract We present James Webb Space Telescope observations of the globular cluster NGC 6397 and use them to extend to infrared wavelengths the characterization of the cluster's entire white dwarf (WD) cooling sequence (CS). The data allows us to probe fundamental astrophysical WD properties and to search for evidence in their colors for (or against ...
L. R. Bedin, D. Nardiello, M. Salaris, M. Libralato, P. Bergeron, A. J. Burgasser, D. Apai, M. Griggio, M. Scalco, J. Anderson, R. Gerasimov, A. Bellini   +11 more
wiley   +1 more source

Gaia23ckh: Symbiotic outburst of the assumed Mira variable V390 Sco

Astronomische Nachrichten, Volume 345, Issue 5, June 2024.
Abstract The poorly studied variable star V390 Sco, previously classified as a Mira pulsator, was detected in a brightening event by the ESA Gaia satellite in September 2023. This work presents an analysis of available archival multifrequency photometric data of this target, along with our spectroscopic observations. Our findings lead to the conclusion
Jaroslav Merc, Peter Velez, Stéphane Charbonnel, Olivier Garde, Pascal Le Dû, Lionel Mulato, Thomas Petit, Jan Skowron   +7 more
wiley   +1 more source

Potential of EBL and cosmology studies with the Cherenkov Telescope Array

, 2013
Very high energy (VHE, E >100 GeV) gamma-rays are absorbed via interaction with low-energy photons from the extragalactic background light (EBL) if the involved photon energies are above the threshold for electron-positron pair creation.
Behera, Bagmeet, Inoue, Susumu, Inoue, Yoshiyuki, Mazin, Daniel, Nakamori, Takeshi, Raue, Martin, Totani, Tomonori   +6 more
core   +1 more source

Kant and extragalactic revolution in astronomy

Theoria, Beograd, 2004
In this paper we briefly consider the role Kant's early philosophy, and notably his "island universes" hypothesis played in the history of astronomy. There are many reasons for this, including the coincidence of Kant's jubilee year with 80 years since Hubble's discovery (1924) of the extragalactic universe.
openaire   +1 more source

Lessons from the apparent peculiar nature of the star TYC 6544‐3483‐1

Astronomische Nachrichten, Volume 345, Issue 4, May 2024.
Abstract We report a radio and optical study of the star TYC 6544‐3483‐1 originally selected as a follow‐up target in the course of our efforts to cross‐identify Galactic high‐energy sources. The star by itself finally turned out to be a very ordinary main‐sequence star despite the initial expectations that apparently pointed to the contrary.
Josep Martí, Pedro L. Luque‐Escamilla, Benito Marcote, Daniel del Ser, Gustavo E. Romero, Cintia S. Peri   +5 more
wiley   +1 more source

Discovery of very high energy gamma-rays from the flat spectrum radio quasar 3C 279 with the MAGIC telescope

, 2008
3C 279 is one of the best studied flat spectrum radio quasars located at a comparatively large redshift of z = 0.536. Observations in the very high energy band of such distant sources were impossible until recently due to the expected steep energy ...
D. Kranich, D. Mazin, E. Lorenz, E. Prandini, F. Tavecchio, Felix A. Aharonian, Frank Rieger, M. Errando, M. Mariotti, M. Teshima, null null, P. Majumdar, R. Bock, R. Wagner, Werner Hofmann   +14 more
core   +1 more source

Effects of Forbush Decreases on the Global Electric Circuit

Space Weather, Volume 22, Issue 4, April 2024.
Abstract The suppression of high‐energy cosmic rays, known as Forbush decreases (FDs), represents a promising factor in influencing the global electric circuit (GEC) system. Researchers have delved into these effects by examining variations, often disruptive, of the potential gradient (PG) in ground‐based measurements taken in fair weather regions.
J. Tacza, G. Li, J.‐P. Raulin
wiley   +1 more source