Zobrazeno 1 - 10
of 1 433
pro vyhledávání: '"Pelt, J."'
Publikováno v:
A&A 615, A111 (2018)
Period estimation is one of the central topics in astronomical time series analysis, where data is often unevenly sampled. Especially challenging are studies of stellar magnetic cycles, as there the periods looked for are of the order of the same len
Externí odkaz:
http://arxiv.org/abs/1712.08235
Debate over the existence of branches in the stellar activity-rotation diagrams continues. Application of modern time series analysis tools to study the mean cycle periods in chromospheric activity index is lacking. We develop such models, based on G
Externí odkaz:
http://arxiv.org/abs/1712.08240
Publikováno v:
A&A 599, A31 (2017)
We study the alignment of galaxies relative to their local environment in SDSS-DR8 and, using these data, we discuss evolution scenarios for different types of galaxies. We defined a vector field of the direction of anisotropy of the local environmen
Externí odkaz:
http://arxiv.org/abs/1611.08378
Autor:
Karak, Bidya Binay, Kapyla, Petri J., Kapyla, Maarit J., Brandenburg, Axel, Olspert, N., Pelt, J.
Publikováno v:
A&A 576, A26 (2015)
Late-type stars rotate differentially owing to anisotropic turbulence in their outer convection zones. The rotation is called solar-like (SL) when the equator rotates fastest and anti-solar (AS) otherwise. Hydrodynamic simulations show a transition f
Externí odkaz:
http://arxiv.org/abs/1407.0984
Publikováno v:
A&A 572, A8 (2014)
Context. Galaxies in the Universe form chains (filaments) that connect groups and clusters of galaxies. The filamentary network includes nearly half of the galaxies and is visually the most striking feature in cosmological maps. Aims. We study the di
Externí odkaz:
http://arxiv.org/abs/1406.4357
The light curves of variable stars are commonly described using simple trigonometric models, that make use of the assumption that the model parameters are constant in time. This assumption, however, is often violated, and consequently, time series mo
Externí odkaz:
http://arxiv.org/abs/1109.2460
Estimation of time delays from a noisy and gapped data is one of the simplest data analysis problems in astronomy by its formulation. But as history of real experiments show, the work with observed data sets can be quite complex and evolved. By analy
Externí odkaz:
http://arxiv.org/abs/1105.5991
The sunspots and other solar activity indicators tend to cluster on the surface of the Sun.These clusters very often occur at certain longitudes that persist in time.It is of general interest to find new and simple ways to characterize the observed d
Externí odkaz:
http://arxiv.org/abs/0908.4155
Long time photometric monitoring programs of gravitational lens systems are often carried on using modest equipment. The resolution of such observations is limited and some of the images may remain unresolved. It may be still possible to find a full
Externí odkaz:
http://arxiv.org/abs/0707.1235
Longtime monitoring of gravitational lens systems is often done using telescopes and recording equipment with modest resolution. Still, it would be interesting to get as much information as possible from the measured lightcurves. From high resolution
Externí odkaz:
http://arxiv.org/abs/astro-ph/0611384