A5066468463- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Pulsars and Gravitational Waves Research
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Radio Astronomy Observations and Technology
- Particle physics theoretical and experimental studies
- Historical Geography and Cartography
- Gyrotron and Vacuum Electronics Research
- Neutrino Physics Research
- Particle Accelerators and Free-Electron Lasers
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Archaeological Research and Protection
- Ancient Mediterranean Archaeology and History
- Archaeology and Historical Studies
- Superconducting Materials and Applications
- Classical Antiquity Studies
- Space Satellite Systems and Control
- Complex Systems and Time Series Analysis
Jagiellonian University
2012-2024
ABSTRACT OJ 287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts that are predictable in binary black hole model. The model predicted major outburst 2015 December. We found the did occur within expected time range, peaking on December 5 at magnitude 12.9 R -band. Based Swift /XRT satellite measurements and polarization data, we find it included thermal component. Its timing provides an accurate estimate for spin of primary hole, . present also...
Abstract Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission gravitational waves (GWs). We show that observations associated binary black hole (BBH) central engine blazar OJ 287 demand inclusion radiation reaction effects beyond quadrupolar order. It turns out even certain hereditary contributions to GW required predict impact flare timings 287. develop an approach incorporates this effect into BBH...
Detection of periodicity in the broad-band non-thermal emission blazars has so far been proven to be elusive. However, there are a number scenarios which could lead quasi-periodic variations blazar light curves. For example, orbital or thermal/viscous period accreting matter around central supermassive black holes could, principle, imprinted multi-wavelength small-scale jets, carrying as such crucial information about plasma conditions within jet launching regions. In this paper, we present...
Abstract We present the results of our power spectral density analysis for BL Lac object OJ 287, utilizing Fermi -LAT survey at high-energy γ -rays, Swift -XRT in X-rays, several ground-based telescopes and Kepler satellite optical, radio GHz frequencies. The light curves are modeled terms continuous-time autoregressive moving average (CARMA) processes. Owing to inclusion data, we were able construct first time optical variability spectrum a blazar without any gaps across ∼6 dex temporal Our...
We report new mid-eclipse times of the two close binaries NSVS14256825 and HS0705+6700, harboring an sdB primary a low-mass main-sequence secondary. Both objects display clear variations in measured orbital period, which can be explained by action third object orbiting binary. If this interpretation is correct, giant planet with mass roughly 12 M_Jup. For we provide evidence that strengthens case for suggested periodic nature eclipse time variation reduces uncertainties parameters brown...
We searched for extrasolar planets around pulsating stars by examining $\textit{Kepler}$ data transit-like events hidden in the intrinsic variability. All Short Cadence observations targets with 6000 K $< T_{\rm eff} <$ 8500 were visually inspected following removal of pulsational signals sinusoidal fits. Clear detected KIC 5613330 and 8197761. is a confirmed exoplanet host (Kepler-635b), where transit period determined here consistent literature value. 8197761 $\gamma$ Doradus - $\delta$...
The cyclic behaviour of (O-C) residuals eclipse timings in the sdB+M eclipsing binary NSVS 14256825 was previously attributed to one or two Jovian-type circumbinary planets. We report 83 new that not only fill gaps those already published but also extend time span diagram by three years. Based on archival and our data spanning over more than 17 years we re-examined up date system (O-C). revealed systematic, quasi-sinusoidal variation deviating from an older linear ephemeris about 100 s. It...
Abstract Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for 128 SU UMa-type dwarf novae observed mainly during 2015–2016 season and characterized these objects. The data have improved distribution orbital periods, relation between period variation superhumps, variations rebrightening type in WZ Sge-type Coupled with new measurements mass ratios using growing stages now a clearer statistically greatly evolutionary path near...
Abstract We report on the analysis of 34 years photometric observations pulsating helium atmosphere white dwarf GD358. The complete data set includes archival from 1982 to 2006, and 1195.2 hr new 2007 2016. From this set, we extract 15 frequencies representing g-mode pulsation modes, adding 4 modes 11 known previously. present evidence that these are ℓ = 1 13 which belong a consecutive sequence in radial overtone k . perform detailed asteroseismic using models include parameterized, complex,...
We report on the results of a multiwavelength monitoring campaign bright, nearby Seyfert galaxy, Ark 120 using ~50-day observing programme with Swift and ~4-month co-ordinated ground-based campaign, predominantly Skynet Robotic Telescope Network. find to be variable at all optical, UV, X-ray wavelengths, variability observed well-correlated between wavelength bands short timescales. perform cross-correlation analysis across available bands, detecting time delays emission in band V, B UVW1...
We report optical photometric and polarimetric observations of the blazar OJ 287 gathered during 2016/17. The high level activity, noticed after General Relativity Centenary flare, is argued to be part follow-up flares that exhibited levels polarization originated in primary black hole jet. propose were induced as a result accretion disk perturbations, travelling from site impact towards SMBH. timings inferred our allowed us estimate propagation speed these perturbations. Additionally, we...
Abstract Continuing the project undertaken by Kato et al. (2009), we collected times of superhump maxima for 56 SU UMa-type dwarf novae mainly observed during 2013–2014 season and characterized these objects. We detected negative superhumps in VW Hyi indicated that low number normal outbursts some supercycles can be interpreted as a result disk tilt. This finding, combined with Kepler observation V1504 Cyg V344 Lyr, suggests tilt is responsible modulating outburst pattern novae. also studied...
The Kepler mission observations, taken in the long cadence mode, have a time resolution of about 30 min. In this paper, we investigate how binning influences shapes light curves eclipsing binaries. A simulated curve contact binary exhibiting flat-bottom secondary minimum was applied for purpose. We found that caused change variation amplitude and shape minima. modelled corresponding to periods between 0.2 2 d using code does not account derived parameters. It turned out only when period is...
We analyse the light curve in R band of blazar OJ287, gathered during 2015/2016 observing season. did a search for quasi-periodic oscillations (QPOs) using several methods over wide range timescales. No statistically significant periods were found high-frequency domain both ground-based data and Kepler observations. In longer-period domain, Lomb–Scargle periodogram revealed peaks above 99% significance level. The longest one—about 95 days—corresponds to innermost stable circular orbit (ISCO)...
Abstract We explore the disk–jet connection in broad-line radio quasar 4C+74.26, utilizing results of multiwavelength monitoring source. The target is unique that its radiative output at wavelengths dominated by a moderately beamed nuclear jet, optical frequencies accretion disk, and hard X-ray range disk corona. Our analysis reveals correlation (local global significance 96% 98% respectively) between bands, with lagging behind jet 250 ± 42 days. discuss possible explanation for this,...
This work studies the significance of lightcurve intrinsic variability in numerical modeling contact binaries. Using synthetic light curves we are showing that starspot-based increases apparent mass ratio by $\Delta q=5$%. For systems with orbital period $P>0.3 d$ effect averaged over long time cancels each other out Kepler Mission-like phase smearing. Further, analyse 47 totally eclipsing Mission We found a sharp cutoff at P = 0.45 d. With curve and observational relations derive physical...
Abstract We present results from an observational campaign on the close binary system 2MASS J16211735+4412541 and a preliminary model based photometric data gathered during quiescent outburst levels. The modeling, done with Wilson–Devinney code its improvements, failed to reproduce properties of system. A secondary minimum obtained within stellar that is too shallow, as well evidence provided by spectroscopic observations performed at quiescence, point toward accretion disk surrounding one...
ABSTRACT OJ 287 is a BL Lacertae type quasar in which the active galactic nucleus (AGN) outshines host galaxy by an order of magnitude. The only exception to this may be at minimum light when AGN activity so low that make quite considerable contribution photometric intensity source. Such dip or fade occurred 2017 November, its brightness was about 1.75 mag lower than recent mean level. We compare observations with similar fades observed earlier 1989, 1999, and 2010. It appears there...
We present solutions of the BVRI-light curve numerical modeling for five low-mass ratio totally eclipsing contact binary stars.One object required introduction a cool star spot to best-fitting model.Only one returned solution with hotter secondary component.None objects third component.
Context. EE Cep is one of few eclipsing binary systems with a dark, dusty disk around an invisible object similar to {\epsilon} Aur. The system characterized by grey and asymmetric eclipses every 5.6 yr, significant variation in their photometric depth, ranging from ~ 0 m .5 2 .0. Aims. main aim the observational campaign eclipse 2014 was test model precession (Galan et al. 2012). We expected that this would be deepest depth Methods. collected multicolor observations almost 30 instruments...
The longitudinal spot migration can be traced with the observation of O'Connell effect and maxima separation variations.Judging by correlations between light curve parameters, processes are confined to polar regions more massive star in a contact binary.