Search Publications
NIRwave: A wave-turbulence-driven solar wind model constrained by PSP observations
Güdel, M.; Boro Saikia, S.; Bartel, M. +2 more
Aims: We generate a model description of the solar wind based on an explicit wave-turbulence-driven heating mechanism, and constrain our model with observational data.
Methods: We included an explicit coronal heating source term in the general 3D magnetohydrodynamic code NIRVANA to simulate the properties of the solar wind. The adapted h…
The Transition Region of Solar Flare Loops
Antiochos, Spiro K.; Young, Peter R.; Gontikakis, Costis
The transition region between the Sun's corona and chromosphere is important to the mass and energy transfer from the lower atmosphere to the corona; consequently, this region has been studied intensely with ultraviolet and extreme ultraviolet (EUV) observations. A major result of these studies is that the amount of plasma at low temperatures, <…
Investigating the Superorbital Modulations in 4U 1909 + 07, IGR J16418-4532, and IGR J16479-4514 with Swift XRT, BAT, and NuSTAR Observations
Pottschmidt, Katja; Corbet, Robin H. D.; Coley, Joel B. +2 more
A puzzling variety of superorbital modulations has been discovered in several supergiant high mass X-ray binaries (sgHMXBs). To investigate the mechanisms driving these superorbital modulations, we have analyzed long-term Neil Gehrels Swift Observatory (Swift) Burst Alert Telescope (BAT) observations of three sgHMXBs: 4U 1909 + 07, IGR J16418-4532…
Imaging of HH80-81 Jet in the Near-infrared Shock Tracers H2 and [Fe II]
Vig, S.; Tej, A.; Mohan, Sreelekshmi +1 more
The HH80-81 system is one of the most powerful jets driven by a massive protostar. We present new near-infrared (NIR) line imaging observations of the HH80-81 jet in the H2 (2.122 µm) and [Fe II] (1.644 µm) lines. These lines trace not only the jet close to the exciting source but also the knots located farther away. We have…
Discovery of δ Sct components in eclipsing binary systems IQ CMa, AW men and W Vol
Ulaş, Burak; Ulusoy, Ceren
We present the first evidence on the δ Sct type pulsations of the primary components of three eclipsing binaries IQ CMa, AW Men, and W Vol in the Transiting Exoplanet Survey Satellite (TESS) field. A comprehensive investigation of the binary properties is conducted. The light curves of the systems are analysed and the frequency analyses are perfor…
Multiband optical variability of a newly discovered 12 blazars sample from 2013 - 2019
Gupta, Alok C.; Damljanović, Goran; Bhatta, Gopal +2 more
Here we present the first optical photometric monitoring results of a sample of 12 newly discovered blazars from the ICRF - Gaia CRF astrometric link. The observations were performed from April 2013 to August 2019 using eight telescopes located in Europe. For a robust test for the brightness and colour variability, we use Abbé criterion and F-test…
Five-minute oscillations of photospheric and chromospheric swirls
Liu, Jiajia; Mathioudakis, Mihalis; Erdélyi, Robert +1 more
Context. Swirls are ubiquitous in the solar atmosphere. They are thought to be related to the excitation of different modes of magnetohydrodynamic waves and pulses, as well as spicules. However, statistical studies of their collective behaviour are rare.
Aims: We aim to study the collective as well as the individual behaviour of photospheric …
Asteroseismology of the Pulsating Extremely Low-mass White Dwarf SDSS J111215.82 + 111745.0: A Model with p-mode Pulsations Consistent with the Observations
Su, Jie; Li, Yan
SDSS J111215.82+111745.0 is the second pulsating extremely low-mass white dwarf discovered. Two short-period pulsations, 107.56 and 134.275 s, were detected on this star, which would be the first observed pressure mode (p-mode) pulsations observed on a white dwarf. While the two potential p-modes have yet to be confirmed, they make SDSS J111215.82…
Coronal Abundances in an Active Region: Evolution and Underlying Chromospheric and Transition Region Properties
Testa, Paola; Martínez-Sykora, Juan; De Pontieu, Bart
The element abundances in the solar corona and solar wind are often different from those of the solar photosphere, typically with a relative enrichment of elements with low first ionization potential (FIP effect). Here, we study the spatial distribution and temporal evolution of the coronal chemical composition in an active region (AR) over about …
Stellar clustering and the kinematics of stars around Collinder 121 using Gaia DR3
Ward-Thompson, Derek; Fleming, Graham D.; Kirk, Jason M.
We study the region around Collinder 121 (Cr 121) using newly available 6D data from the Gaia DR3 catalogue. Situated in the third quadrant, near the Galactic plane, Collinder 121 lies in the region of Canis Major centred around (l, b) ≈(236°, -10°). Previous studies have suggested that the stellar associations in this region comprise an OB associ…