Related papers: The Kepler RR Lyrae SC Data Set: Period Variation …
In this letter we present the results of a wavelet analysis of the radio light curve of the BL Lac Object PKS B0048-097 from the University of Michigan Radio Astronomy Observatory monitoring program at 8GHz during twenty-five years, from…
The light curves of 50 RRab (RR0) stars in M5 collected in Paper I are investigated to detect Blazhko modulation. 18 Blazhko stars are identified, and modulation is suspected in two additional cases. The mean pulsation period of Blazhko…
The amplitude and phase modulation observed in a significant fraction of the RR Lyrae variables - the Blazhko effect - represents a long-standing enigma in stellar pulsation theory. No satisfactory explanation for the Blazhko effect has…
We present the results of a systematic search for multiperiodic pulsators among the Galactic Bulge RR Lyrae stars of the OGLE-1 sample. We identify one "canonical" double-mode variable (RRd star) pulsating in two radial modes. In 38 stars…
Pulsations in RR Lyrae stars and classical Cepheids were thought to be relatively simple since they typically pulsate only in one or two radial modes. This picture changes at a closer look when modulation or additional low-amplitude signals…
The stellar parameters of RR Lyrae stars vary considerably over a pulsation cycle, and their determination is crucial for stellar modelling. We present a detailed spectroscopic analysis of the pulsating star RR Lyr, the prototype of its…
We present the hydrodynamic BL Herculis-type models which display a long-term modulation of pulsation amplitudes and phases. The modulation is either strictly periodic or it is quasi-periodic, with the modulation period and modulation…
A new, extended time-series photometry of M3 RR Lyrae stars has revealed that four of the ten double-mode stars show large-amplitude Blazhko modulation of both radial modes. The first, detailed analysis of the peculiar behavior of the…
The All Sky Automated Survey (ASAS) monitors bright stars (8 mag < V < 14 mag) south of declination +28 deg. The ASAS Catalogue of Variable Stars (ACVS) presently contains 50,099 objects; among them are 2212 objects classified as RR Lyrae…
We present the results of collaborative observations of three RR Lyrae stars (CX Lyr, NU Aur and VY CrB) which have a strong Blazhko effect. This work has been initiated and performed in the framework of the GEOS RR Lyr Survey (Groupe…
We present the first paper of a series focused on the Blazhko effect in RR Lyrae type stars pulsating in the fundamental mode, that are located in the Galactic bulge. A~comprehensive overview about the incidence rate and light-curve…
The CoRoT satellite supplied the scientific community with a huge data base of variable stars. Among them the RR Lyrae stars have intensively been discussed in numerous papers in the last few years, but the latest runs have not been checked…
Well-sampled optical and radio light curves of BL Lacertae in B, V, R, I bands and 4.8, 8.0, 14.5 GHz from 1968 to 2014 were presented in this paper. A possible $1.26 \pm 0.05$ yr period in optical bands and a $7.50 \pm 0.15$ yr period in…
In this paper, the compiled long-term optical and infrared measurements of some blazars are used to analyze the variation properties and the optical data are used to search for periodicity evidence in the lightcurve by means of the…
For the first time connection between the pulsation and modulation properties of RR Lyrae stars has been detected. Based on the available data it is found that the possible range of the modulation frequencies, i.e, the possible maximum…
We study the long term Kepler light curve of the blazar W2R 1926+42 ($\sim$ 1.6 years) which indicates a variety of variability properties during different intervals of observation. The normalized excess variance, $F_{\rm var}$ ranges from…
We present the results of a photometry campaign of TU Com performed over a five-year time span. The analysis showed that the possible Blazhko period of 75 days published by the General Catalogue of Variable Stars is not correct. We…
We report a possible detection of an ~4.6-hour quasi-periodic oscillation (QPO) in the 0.3-10 keV emission of the high-energy peaked blazar PKS 2155-304 from a 64 ks observation by the XMM-Newton EPIC/pn detector. We identify a total…
A high percentage of the astrophysically important RR Lyrae stars show a periodic amplitude and/or phase modulation of their pulsation cycles. More than a century after its discovery, this "Blazhko effect" still lacks acceptable theoretical…
The overtone and multi-mode RR Lyrae stars in the globular cluster M3 are studied using a 200-d long, $B,V$ and $I_{\mathrm C}$ time-series photometry obtained in 2012. 70\% of the 52 overtone variables observed show some kind of…