Search Publications
A method for identifying metal-poor stars with Gaia BP/RP spectra
Lind, K.; Xylakis-Dornbusch, T.; Christlieb, N. +1 more
Context. The study of the oldest and most metal-poor stars in our Galaxy promotes our understanding of the Galactic chemical evolution and the beginning of Galaxy and star formation. However, they are notoriously difficult to find, with only seven stars at [Fe/H] < −5.0 having been detected to date. Thus, the spectrophotometric data of 219 mill…
White-light QFP wave train and the associated failed breakout eruption
Yao, Surui; Shen, Yuandeng; Zhou, Chengrui +5 more
Quasi-periodic fast-propagating (QFP) magnetosonic wave trains are commonly observed in the low corona at extreme ultraviolet wavelength bands. Here, we report the first white-light imaging observation of a QFP wave train propagating outwardly in the outer corona ranging from 2 to 4 R⊙. The wave train was recorded by the Large Angle Spe…
Pushing sub-arcsecond resolution imaging down to 30 MHz with the trans-European International LOFAR Telescope
Bondi, M.; Brunetti, G.; Callingham, J. R. +12 more
Relatively little information is available about the Universe at ultra-low radio frequencies (ULF; i.e., below 50 MHz), although the ULF spectral window contains a wealth of unique diagnostics for studying galactic and extragalactic phenomena. Subarcsecond resolution imaging at these frequencies is extremely difficult, due to the long baselines (&…
Gaia-ESO Survey: Detailed elemental abundances in red giants of the peculiar globular cluster NGC 1851
Gilmore, G.; Guiglion, G.; Lardo, C. +24 more
Context. NGC 1851 is one of several globular clusters for which multiple stellar populations of the subgiant branch have been clearly identified and a difference in metallicity detected. A crucial piece of information on the formation history of this cluster can be provided by the sum of A(C+N+O) abundances. However, these values have lacked a gen…
Sublimation origin of active asteroid P/2018 P3
Mutchler, Max; Jewitt, David; Agarwal, Jessica +4 more
Context. Active asteroids show (typically transient) cometary activity, driven by a range of processes. A sub-set, sometimes called main-belt comets, may be driven by sublimation and so could be useful for tracing the present-day distribution of asteroid ice. Object P/2018 P3 has a Tisserand parameter 3.096 but a high eccentricity 0.415, placing i…
High-resolution near-infrared spectroscopy of globular cluster and field stars toward the Galactic bulge
Lee, Young-Wook; Koch-Hansen, Andreas J.; Hong, Seungsoo +2 more
Globular clusters (GCs) play an important role in the formation and evolution of the Milky Way. New candidates are continuously found, particularly in the high-extinction low-latitude regions of the bulge, although their existence and properties have yet to be verified. In order to investigate the new GC candidates, we performed high-resolution ne…
Importance of radiative pumping for the excitation of the H2O submillimeter lines in galaxies
González-Alfonso, Eduardo; Pereira-Santaella, Miguel; Yang, Chentao +3 more
H2O submillimeter emission is a powerful diagnostic of the molecular interstellar medium in a variety of sources, including low- and high-mass star-forming regions of the Milky Way, and from local to high-redshift galaxies. However, the excitation mechanism of these lines in galaxies has been debated, preventing a basic consensus on the…
Chromospheric emission from nanoflare heating in RADYN simulations
De Pontieu, B.; Rouppe van der Voort, L.; Carlsson, M. +4 more
Context. Heating signatures from small-scale magnetic reconnection events in the solar atmosphere have proven to be difficult to detect through observations. Numerical models that reproduce flaring conditions are essential in understanding how nanoflares may act as a heating mechanism of the corona.
Aims: We study the effects of non-thermal e…
Numerical and experimental evidence for a new interpretation of residence times in space
Heber, B.; Herbst, K.; Engelbrecht, N. Eugene +2 more
Aims: We investigate the energy dependence of Jovian electron residence times, which allows for a deeper understanding of adiabatic energy changes that occur during charged particle transport, as well as of their significance for simulation approaches. Thereby we seek to further validate an improved approach to estimate residence times numeri…
The CH4 abundance in Jupiter's upper atmosphere
Sánchez-López, A.; Snellen, I. A. G.; López-Puertas, M. +3 more
Hydrocarbon species, and in particular CH4, play a key role in the stratosphere-thermosphere boundary of Jupiter, which occurs around the µ-bar pressure level. Previous analyses of solar occultation, He and Ly-α airglow, and ISO/SWS measurements of the radiance around 3.3 µm have inferred significantly different methane conc…