Determining the magnetic field related to solar spicules is vital for developing adequate models of these plasma jets, which are thought to play a key role in...
On the post-common-envelope central star of the planetary nebula NGC 2346
The common-envelope phase is one of the most poorly understood phases of (binary) stellar evolution, in spite of its importance in the formation of a wide range...
On the Reliability of Microvariability Tests in Quasars
Microvariations probe the physics and internal structure of quasars. Unpredictability and small flux variations make this phenomenon elusive and difficult to...
On the Use of Field RR Lyrae as Galactic Probes. I. The Oosterhoff Dichotomy Based on Fundamental Variables
We collected a large data set of field RR Lyrae stars (RRLs) by using catalogs already available in the literature and Gaia DR2. We estimated the iron...
On the use of photometric redshifts for X-ray selected AGNs
In this paper we present photometric redshift estimates for a sample of X-ray selected sources detected in the wide-field ( 2 deg^2), bright [ f_X(0.5{-}8 keV)...
On the use of the Fourier transform to determine the projected rotational velocity of line-profile variable B stars
Context. The Fourier transform method is a popular tool for deriving the rotational velocities of stars from their spectral line profiles. However, its domain...
Once in a blue moon: detection of `bluing' during debris transits in the white dwarf WD 1145+017
The first transiting planetesimal orbiting a white dwarf was recently detected in K2 data of WD 1145+017 and has been followed up intensively. The multiple...
Optical and Near-Infrared Calibration of AGN Field Stars: An All-Sky Network of Faint Stars Calibrated on the Landolt System
We present a total of 12,436 photometric measures of 371 field stars of 26 quasars in the visible (UBVRI) and 22,276 photometric measures of 122 field stars of...
Optical and near-infrared spectroscopy of the black hole transient 4U 1543-47 during its 2021 ultra-luminous state
We present simultaneous optical and near-infrared spectra obtained during the 2021 outburst of the black hole transient 4U 1543-47. The X-ray hardness-intensity...