Results 71 to 80 of about 53,848 (207)
Open Astronomy, 2016 Flux density variations of the extragalactic radio source OJ 287 are studied by applying the wavelet and the singular spectrum methods to the long-term monitoring data at 14.5, 8.0 and 4.8 GHz acquired at the University of Michigan Radio Astronomy ...
Donskykh Ganna
doaj +1 more source
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 +11 more
wiley +1 more source
The Astrophysical JournalWe investigate the association between galaxies and neutral O i absorption systems at z ∼ 6, which trace metal-enriched gas during the epoch of reionization.
Jack Higginson +10 more
doaj +1 more source
, 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 +14 more
core +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 +7 more
wiley +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 +5 more
wiley +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
The Astrophysical JournalWe investigate how stellar disks sustain their ultrathin structure throughout their evolution. We follow the evolution of ultrathin stellar disks with varying dark matter (DM) halo concentration ( c ) using collisionless N -body simulations with AREPO ...
K. Aditya, Arunima Banerjee
doaj +1 more source
Odessa Astronomical Publications, 2014 We investigated the monitoring data of extragalactic source BL Lac. This monitoring was held withUniversityofMichigan26-meter radio telescope. To study flux density of extragalactic source BL Lac at frequencies of 14.5, 8 and 4.8 GHz, the wavelet ...
G. I. Donskykh +3 more
doaj +1 more source
Extragalactic Stellar Astronomy with Blue Supergiants
, 2007 2 pages. To appear in the proceedings of the workshop "Massive Stars: Fundamental Parameters and Circumstellar Interactions", Rev. Mex. Astron. Astrofis.
Przybilla, N. +5 more
openaire +2 more sources