Related papers: The BlueWalker 3 Satellite Has Faded
The orbital solutions for astrometric (unresolved) binary stars provided in the Gaia mission Data Release 3 reveal an obvious deficit of face-on orbits with line-of-sight inclinations close to 0 or $\pi$. This is shown to be an intrinsic…
We present the measurements of sky surface brightness on Mount Graham International Observatory obtained during the first binocular-mode science runs at the Large Binocular Telescope (LBT). A total of 860 images obtained on 23 moonless…
BICEP3 is a 520 mm aperture on-axis refracting telescope at the South Pole, which observes the polarization of the cosmic microwave background (CMB) at 95 GHz to search for the B-mode signal from inflationary gravitational waves. In…
Solar flares are occasionally responsible for severe Space Weather events, which can affect space-borne and ground-based infrastructures, endangering anthropic technological activities and even human health and safety. Thus, an essential…
A model of the brightness of the visorsat Starlink spacecraft is presented based on published information on the engineering design and from analysis of 131 observations of individual visorsats in late 2020. Comments are offered on the…
We argue that, in general, observational studies of Be-star rotation have paid insufficient attention to the effects of equatorial gravity darkening. We present new line-profile calculations that emphasize the insensitivity of line width to…
During strong magnetic storms, the errors of determination of the range, frequency Doppler shift and angles of arrival of transionospheric radio signals exceeds the one for magnetically quiet days by one order of magnitude as a minimum.…
We investigate the relativistic jet of the powerful radio-emitting blazar J1429+5406 at redshift z=3.015. Our understanding of jet kinematics in z>3 quasars is still rather limited, based on a sample of less than about 50 objects. The…
Although substantial progress has been made in reconciling LCDM simulations with the observed abundance and distribution of satellite galaxies, important tensions persist. Studying satellite systems around spiral galaxies thus remains key…
We studied the variability of the linear polarization and brightness of the $\gamma$-ray binary LS I +61 303. High-precision BVR photopolarimetric observations were carried out with the Dipol-2 polarimeter on the 2.2 m remotely controlled…
Mrk926 is known to be a highly variable AGN with very broad line profiles. We studied the continuum and line profile variations of this object with high temporal resolution in order to determine its broad-line region structure and to derive…
Here we report on the results of the WEBT photo-polarimetric campaign targeting the blazar S5~0716+71, organized in March 2014 to monitor the source simultaneously in BVRI and near IR filters. The campaign resulted in an unprecedented…
Comparing solar and stellar brightness variations is hampered by the difference in spectral passbands used in observations as well as by the possible difference in the inclination of their rotation axes from the line of sight. We calculate…
The spatial distribution of the satellite populations of the Milky Way and Andromeda are puzzling in that they are nearly perpendicular to the disks of their central galaxies. To understand the origin of such configurations we study the…
We present quasar bolometric corrections using the [O III] $\lambda5007$ narrow emission line luminosity based on the detailed spectral energy distributions of 53 bright quasars at low to moderate redshift ($0.0345<z<1.0002$). We adopted…
BD And is a fairly bright (V = 10.8), active and close (P = 0.9258 days) eclipsing binary. The cyclic variability of the apparent orbital period as well as third light in the light curves indicate the presence of an additional late-type…
We report results from analyzing the B612 asteroid observation data taken by the sCMOS cameras on board of Planet SkySat-3 using the synthetic tracking technique. The analysis demonstrates the expected sensitivity improvement in the…
Atmospheric refraction modifies the apparent position of objects in the sky. We computed the lateral translation that is to be considered for short-range applications, such as wavefront sensing and meteor trajectories. We aim to calculate…
The LAT instrument, onboard the Fermi satellite, in its first three months of operation detected more than 100 blazars at more than the 10 sigma level. This is already a great improvement with respect to its predecessor, the instrument…
We aim to study the phase spiral in the Milky Way (MW) with Gaia DR3. We used an edge detection algorithm to find the border of the phase spiral, allowing us to robustly quantify its shape at different positions and for different…