Search Publications
Evidence of the multi-thermal nature of spicular downflows. Impact on solar atmospheric heating
Joshi, Jayant; Martínez-Sykora, Juan; De Pontieu, Bart +4 more
Context. Spectroscopic observations of the emission lines formed in the solar transition region commonly show persistent downflows on the order of 10−15 km s−1. The cause of such downflows, however, is still not fully clear and has remained a matter of debate.
Aims: We aim to understand the cause of such downflows by studying the c…
INTEGRAL Limits on Past High-energy Activity from FRB 20200120E in M81
Götz, D.; Mereghetti, S.; Rigoselli, M. +1 more
The repeating fast radio burst FRB 20200120E is located in a globular cluster belonging to the nearby M81 galaxy. Its small distance (3.6 Mpc) and accurate localization make it an interesting target to search for bursting activity at high energies. From 2003 November to 2021 September, the INTEGRAL satellite has obtained an exposure time of 18 Ms …
Measuring chemical abundances with infrared nebular lines: HII-CHI-MISTRY-IR
Spinoglio, L.; Amorín, R.; Pérez-Montero, E. +2 more
We provide a new method for deriving heavy element abundances taking advantage of the unique suite of fine-structure lines in the mid- to far-infrared (IR) range. Using grids of photo-ionisation models that cover a wide range in O/H and N/O abundances and ionisation parameter, our code HII-CHI-MISTRY-IR (HCM-IR) provides model-based abundances bas…
Hunting for intermediate-mass black holes in globular clusters: an astrometric study of NGC 6441
van der Marel, Roeland P.; Neumayer, Nadine; Watkins, Laura L. +6 more
We present an astrometric study of the proper motions (PMs) in the core of the globular cluster NGC 6441. The core of this cluster has a high density and observations with current instrumentation are very challenging. We combine ground-based, high-angular-resolution NACO@VLT images with Hubble Space Telescope ACS/HRC data and measure PMs with a te…
Future Prospects for Solar EUV and Soft X-ray Solar Spectroscopy Missions
Young, Peter R.
Future prospects for solar spectroscopy missions operating in the extreme ultraviolet (EUV) and soft X-ray (SXR) wavelength ranges, 1.2--1600~\AA, are discussed. NASA is the major funder of Solar Physics missions, and brief summaries of the opportunities for mission development under NASA are given. Upcoming major solar missions from other nations…
The AMBRE Project: Origin and evolution of sulfur in the Milky Way
Recio-Blanco, A.; de Laverny, P.; Álvarez, M. A. +4 more
Context. Sulfur is a volatile chemical element that plays an important role in tracing the chemical evolution of the Milky Way and external galaxies. However, its nucleosynthesis origin and abundance variations in the Galaxy are still unclear because the number of available stellar sulfur abundance measurements is currently rather small.
Aims…
A Search for Wandering Black Holes in the Milky Way with Gaia and DECaLS
Ting, Yuan-Sen; Strader, Jay; Greene, Jenny E. +6 more
We present a search for "hypercompact" star clusters in the Milky Way using a combination of Gaia and the Dark Energy Camera Legacy Survey (DECaLS). Such putative clusters, with sizes of ~1 pc and containing 500-5000 stars, are expected to remain bound to intermediate-mass black holes (MBH ≈ 103-105 M⊙) …
Upper limits on the escape fraction of ionizing radiation from galaxies at 2 ≲ z < 6
Ryan-Weber, E. V.; Rafelski, M.; Bassett, R. +3 more
In this work, we investigate upper limits on the global escape fraction of ionizing photons ($f_{\rm esc/global}^{\rm abs}$) from a sample of galaxies probed for Lyman-continuum (LyC) emission characterized as non-LyC and LyC leakers. We present a sample of nine clean non-contaminated (by low-redshift interlopers, CCD problems, and internal reflec…
Configuration of the Earth's Magnetotail Current Sheet
Lin, Yu; Zhang, Xiao-Jia; El-Alaoui, Mostafa +7 more
The spatial scale and intensity of Earth's magnetotail current sheet determine the magnetotail configuration, which is critical to one of the most energetically powerful phenomena in the Earth's magnetosphere, substorms. In the absence of statistical information about plasma currents, theories of the magnetotail current sheets were mostly based on…
A Metallicity Study of F, G, K, and M Dwarfs in the Coma Berenices Open Cluster from the APOGEE Survey
Cunha, Katia; Smith, Verne V.; Souto, Diogo
We present a study of metallicities in a sample of main-sequence stars with spectral types M, K, G, and F (Teff ~3200-6500K and log g ~ 4.3-5.0 dex) belonging to the solar neighborhood young open cluster Coma Berenices. Metallicities were determined using the high-resolution (R = λ/Δ λ ~ 22,500) NIR spectra (λ1.51-λ1.69 µm) of the…