Search Publications
White dwarf-open cluster associations based on Gaia DR2
Paunzen, E.; Prišegen, M.; Piecka, M. +2 more
Context. Fundamental parameters and physical processes leading to the formation of white dwarfs (WDs) may be constrained and refined by discovering WDs in open clusters (OCs). Cluster membership can be utilized to establish the precise distances, luminosities, ages, and progenitor masses of such WDs.
Aims: We compile a list of probable WDs th…
Multi-spacecraft study of the solar wind at solar minimum: Dependence on latitude and transient outflows
Fedorov, A.; Eastwood, J. P.; Owens, M. J. +15 more
Context. The recent launches of Parker Solar Probe, Solar Orbiter (SO), and BepiColombo, along with several older spacecraft, have provided the opportunity to study the solar wind at multiple latitudes and distances from the Sun simultaneously.
Aims: We take advantage of this unique spacecraft constellation, along with low solar activity acro…
Online data analysis system of the INTEGRAL telescope
Paltani, S.; Tramacere, A.; Ferrigno, C. +3 more
Context. During more than 17 years of operation in space, the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) telescope has accumulated a large data set that contains records of hard X-ray and soft γ-ray astronomical sources. These data can be reused in the context of multi-wavelength or multi-messenger studies of astronomical sources a…
Chromospheric Activity of Periodic Variable Stars Based on the LAMOST Low- and Medium-resolution Spectral Survey
Shi, Jianrong; Han, Xianming L.; Zhang, Li-yun +5 more
We present a catalog of 75,867 periodic variable stars from data release 7 of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope. We calculated the chromospheric activity index, equivalent widths for 201,349 spectra, and excess fractional luminosity ( ${R}_{{\rm{H}}\alpha }^{{\prime} }$ ) for 130,796 spectra. Based on the intensity of t…
Double X/Peanut structures in barred galaxies - insights from an N-body simulation
Ciambur, Bogdan C.; Fragkoudi, Francesca; Khoperskov, Sergey +2 more
Boxy, peanut-, or X-shaped 'bulges' are observed in a large fraction of barred galaxies viewed in, or close to, edge-on projection, as well as in the Milky Way. They are the product of dynamical instabilities occurring in stellar bars, which cause the latter to buckle and thicken vertically. Recent studies have found nearby galaxies that harbour t…
Empirical Selection of Auroral Kilometric Radiation During a Multipoint Remote Observation With Wind and Cassini
Jackman, C. M.; Bonnin, X.; Cecconi, B. +5 more
Auroral Kilometric Radiation (AKR) is terrestrial radio emission that originates in particle acceleration regions along magnetic field lines, coinciding with discrete auroral arcs. AKR viewing geometry is complex due to the confinement of the source regions to nightside local times (LTs) and the anisotropy of the beaming pattern, so observations a…
Data-driven Stellar Models
Rix, Hans-Walter; Fouesneau, Morgan; Zucker, Catherine +7 more
We developed a data-driven model to map stellar parameters (Teff, $\mathrm{log}g$ , and $\left[\mathrm{Fe}/{\rm{H}}\right]$ ) accurately and precisely to broadband stellar photometry. This model must, and does, simultaneously constrain the passband-specific dust reddening vector in the Milky Way, R. The model uses a neural network to le…
Ultracool Dwarfs Observed with the Spitzer Infrared Spectrograph. I. An Accurate Look at the L-to-T Transition at 300 Myr from Optical Through Mid-infrared Spectrophotometry
Metchev, Stanimir; Marley, Mark S.; Saumon, Didier +2 more
We present Spitzer IRS 5-14 µm spectra and 16 µm and 22 µm photometry of the T2.5 companion to the ~300 Myr old G0V star HN Peg. We incorporate previous 0.8-5 µm observations to obtain the most comprehensive spectral energy distribution (SED) of an intermediate-gravity L/T-transition dwarf that, together with an accurate Ga…
Super-Eddington accretion on to a stellar mass ultraluminous X-ray source NGC 4190 ULX1
Ghosh, T.; Rana, V.
We present the results of high-quality XMM-NEWTON observations of a ultraluminous X-ray source (ULX) in the galaxy NGC 4190. The detection of spectral cutoff in NGC 4190 ULX1 spectra rules out the interpretation of the ULX to be in a standard low/hard canonical accretion state. We report that the high quality EPIC spectra can be better described b…
Electron Energy Interplay in the Geomagnetic Trap Below the Auroral Acceleration Region
Khazanov, George V.; Glocer, Alex; Chu, Mike
This publication addresses the collisional superthermal electron dynamics below the auroral acceleration region (AAR). This region is the portion of an auroral field line with a field aligned electric field that leads to the formation of precipitating monoenergetic keV electron fluxes that produce the discrete auroral displays observable from the …