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VY Scl-type cataclysmic variable SDSS J154453.60+255348.8: stellar and disc parameters
Wolf, M.; Zharikov, S.; Kára, J. +3 more
We present a new study of the eclipsing cataclysmic variable SDSS J154453.60+255348.8 to determine the object's nature and its system parameters together with the probe of the accretion flow structure in the system. Based on analyses of new simultaneous time-resolved photometric and spectroscopic observations of SDSS J154453.60+255348.8 and using …
Searching for signatures of H α spicule-like features in the solar transition region
Shetye, Juie; Doyle, J. Gerry; Vilangot Nhalil, Nived
New instruments and telescopes covering the optical and ultraviolet spectral regions have revealed a range of small-scale dynamic features, many which may be related. For example, the range of spicule-like features hints towards a spectrum of features and not just two types; however, direct observational evidence in terms of tracking spicules acro…
Spectroscopic study of Herbig Ae/Be stars in the Galactic anti-centre region from LAMOST DR5
Arun, R.; Mathew, Blesson; Kartha, Sreeja S. +3 more
We study a sample of 119 Herbig Ae/Be stars in the Galactic anti-centre direction using the spectroscopic data from large sky area multi-object fiber spectroscopic telescope survey program. Emission lines of hydrogen belonging to the Balmer and Paschen series, and metallic lines of species such as Fe II, O I, Ca II triplet are identified. A modera…
Testing the planetary hypothesis of NY Virginis: anticipated change in the eclipse timing trend within the next five years
Baştürk, Özgür; Esmer, Ekrem Murat; Selam, Selim Osman
Regarding the recent debate about the potential circumbinary exoplanets around NY Virginis (NY Vir), we analysed mid-eclipse timings of NY Vir using archival photometric data as well as our own observations and the ones from TESS. For this purpose, we first modelled the available eclipse light curves of the binary system to determine the masses of…
Redshift-luminosity characterization of active galactic nucleus galaxies having obscuring dusty material using the spectral energy distribution from the X-ray to far-infrared
Gadallah, Kamel A. K.
The spectral energy distribution (SED) from the X-ray to far-IR is used to characterize active galactic nuclei (AGNs) having obscuring dusty material. A sample of 73 AGNs, with redshifts of z < 2.5, is subdivided based on the optical spectra into subgroups of type 1 and 2 AGNs and no-AGN. The X-CIGALE code is used to produce the SEDs of these g…
Revisiting multiwavelength data on the supersoft X-ray source CAL 83
D'Amico, F.; Jablonski, F.; Stecchini, P. E. +1 more
In this study, we revisit public data on the supersoft X-ray source CAL 83 in the Large Magellanic Cloud. A significant part of our analysis is focused on XMM-Newton X-ray observations, in which updated data reduction procedures and quality assessment were applied. We report on the capability of publicly available hot atmosphere models in describi…
A method of photometric data extraction for asteroids from time-domain surveys
Muinonen, Karri; Penttilä, Antti; Xiang, Yue +9 more
The lightcurves of asteroids are essential for determining their physical characteristics, including shape, spin, size, and surface composition. However, most asteroids are missing some of these basic physical parameters due to lack of photometric data. Although a few telescopes or surveys are specially designed for photometric lightcurve observat…
Colliding winds in WR21 and WR31 - I. The X-ray view
Nazé, Yaël; Gosset, Eric; Rauw, Gregor +2 more
WR21 and WR31 are two WR + O binaries with short periods, quite similar to the case of V444 Cyg. The XMM-Newton observatory has monitored these two objects and clearly revealed phase-locked variations as expected from colliding winds. The changes are maximum in the soft band (0.5-2.0 keV, variations by a factor 3-4) where they are intrinsically li…
Time-scale-dependent X-ray to UV time lags of NGC 4593 using high-intensity XMM-Newton observations with Swift and AstroSat
Dewangan, Gulab C.; Singh, Kulinder Pal; McHardy, Ian M. +6 more
We present a 140 ks observation of NGC 4593 with XMM-Newton providing simultaneous and continuous pn X-ray and OM UV (UVW1 2910 Å) light curves, which sample short-time-scale variations better than previous observations. These observations were simultaneous with 22 d of Swift X-ray and UV/optical monitoring reported previously, and 4 d of AstroSat…
Lamp-post with an outflow and the hard state of Cyg X-1
Szanecki, Michał; Niedźwiecki, Andrzej; Klepczarek, Łukasz
Relativistic reflection observed in the hard states of accreting black holes (BH) often shows a weak amplitude relative to the main Comptonization component, which may result from either a disc truncation or a non-isotropy of the X-ray source, e.g. due to a motion away from the reflector. We investigate here the latter case, assuming that the X-ra…