Search Publications
New Homogeneous Dataset of Solar EUV Synoptic Maps from SOHO/EIT and SDO/AIA
Asikainen, T.; Mursula, K.; Hamada, A.
Synoptic maps of solar EUV intensities have been constructed for many decades in order to display the distribution of the different EUV emissions across the solar surface, with each map representing one Carrington rotation (i.e. one rotation of the Sun). This article presents a new solar EUV synoptic map dataset based on full-disk images from the …
Insights into the Formation and Evolution History of the Galactic Disk System
Beers, Timothy C.; Lee, Young Sun; Kim, Young Kwang +1 more
We present a kinematic analysis of a sample of 23,908 G- and K-type dwarfs in the Galactic disk. Based on the α-abundance ratio, [α/Fe], we separated our sample into low-α thin-disk and high-α thick-disk stars. We find a ${V}_{\phi }$ gradient of -28.2 km s-1 dex-1 over [Fe/H] for the thin disk and an almost flat trend of the…
2016 Outburst of H 1743-322: XMM-Newton and NuSTAR View
Dewangan, G. C.; Chand, Swadesh; Tripathi, Prakash +2 more
We report the detection of a type C quasi-periodic oscillation (QPO) along with an upper harmonic in the commensurate ratio of 1:2 in two observations of the low-mass black hole transient H 1743-322 jointly observed by XMM-Newton and NuSTAR during the 2016 outburst. We find that the QPO and the upper harmonic exhibit shifts in their centroid frequ…
Trigonometric parallax of O-rich Mira variable star OZ Gem (IRAS 07308+3037): A confirmation of the difference between the P-L relations of the Large Magellanic Cloud and the Milky Way
Kawabata, Koji; Fujimoto, Masayuki Y.; Yamanaka, Masayuki +11 more
OZ Geminorum (OZ Gem) is a galactic Mira variable in the Milky Way (MW). We measured its annual parallax with VLBI Exploration of Radio Astrometry to be π = 0.806 ± 0.039 mas, corresponding to a distance of D = 1.24 ± 0.06 kpc. Based on multi-epoch infrared observations with the Kagoshima University 1 m telescope, we also derived the mean J-, H-, …
Electron acceleration and radio emission following the early interaction of two coronal mass ejections
Palmerio, E.; Magdalenić, J.; Kilpua, E. K. J. +6 more
Context. Coronal mass ejections (CMEs) are large eruptions of magnetised plasma from the Sun that are often accompanied by solar radio bursts produced by accelerated electrons.
Aims: A powerful source for accelerating electron beams are CME-driven shocks, however, there are other mechanisms capable of accelerating electrons during a CME erupt…
A resistive extension for ideal magnetohydrodynamics
Wright, Alex James; Hawke, Ian
We present an extension to the special relativistic, ideal magnetohydrodynamic (MHD) equations, designed to capture effects due to resistivity. The extension takes the simple form of an additional source term that, when implemented numerically, is shown to emulate the behaviour produced by a fully resistive MHD description for a range of initial d…
seestar: Selection functions for spectroscopic surveys of the Milky Way
Everall, Andrew; Das, Payel
Selection functions are vital for understanding the observational biases of spectroscopic surveys. With the wide variety of multiobject spectrographs currently in operation and becoming available soon, we require easily generalizable methods for determining the selection functions of these surveys. Previous work, however, has largely been focused …
The path to Z And-type outbursts: The case of V426 Sagittae (HBHA 1704-05)
Masetti, N.; Munari, U.; Buil, C. +16 more
Context. The star V426 Sge (HBHA 1704-05), originally classified as an emission-line object and a semi-regular variable, brightened at the beginning of August 2018, showing signatures of a symbiotic star outburst.
Aims: We aim to confirm the nature of V426 Sge as a classical symbiotic star, determine the photometric ephemeris of the light min…
The XXL Survey. XLIV. Sunyaev-Zel'dovich mapping of a low-mass cluster at z ∼ 1: a multi-wavelength approach
Chiappetti, L.; Berta, S.; Altieri, B. +61 more
High-mass clusters at low redshifts have been intensively studied at various wavelengths. However, while more distant objects at lower masses constitute the bulk population of future surveys, their physical state remain poorly explored to date. In this paper, we present resolved observations of the Sunyaev-Zel'dovich (SZ) effect, obtained with the…
Multi-wavelength campaign on NGC 7469. V. Analysis of the HST/COS observations: Super solar metallicity, distance, and trough variation models
Kaastra, J. S.; Kriss, G. A.; Arav, N. +18 more
Context. AGN outflows are thought to influence the evolution of their host galaxies and their super massive black holes. To better understand these outflows, we executed a deep multiwavelength campaign on NGC 7469. The resulting data, combined with those of earlier epochs, allowed us to construct a comprehensive physical, spatial, and temporal pic…