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Patches of Magnetic Switchbacks and Their Origins
de Wit, Thierry Dudok; Velli, Marco; Bale, Stuart D. +18 more
Parker Solar Probe (PSP) has shown that the solar wind in the inner heliosphere is characterized by the quasi omnipresence of magnetic switchbacks ("switchback" hereinafter), local backward bends of magnetic field lines. Switchbacks also tend to come in patches, with a large-scale modulation that appears to have a spatial scale size comparable to …
Confirmation of Water Absorption in the Thermal Emission Spectrum of the Hot Jupiter WASP-77Ab with HST/WFC3
Fortney, Jonathan J.; Stevenson, Kevin B.; Désert, Jean-Michel +11 more
Secondary eclipse observations of hot Jupiters can reveal both their compositions and thermal structures. Previous observations have shown a diversity of hot Jupiter eclipse spectra, including absorption features, emission features, and featureless blackbody-like spectra. We present a secondary eclipse spectrum of the hot Jupiter WASP-77Ab observe…
Luminosity functions of globular clusters in five nearby spiral galaxies using HST/ACS images
Mayya, Y. D.; Rosa-González, D.; Rodríguez-Merino, L. H. +2 more
We here present the luminosity function (LF) of globular clusters (GCs) in five nearby spiral galaxies using the samples of GC candidates selected in Hubble Space Telescope mosaic images in F435W, F555W, and F814W filters. Our search, which surpasses the fractional area covered by all previous searches in these galaxies, has resulted in the detect…
High-precision chemical abundances of Galactic building blocks. II. Revisiting the chemical distinctness of the Helmi streams
Hattori, Kohei; Helmi, Amina; Ishigaki, Miho N. +6 more
Context. The Helmi streams are a kinematic substructure whose progenitor is likely a dwarf galaxy. Although 20 years have passed since their discovery, it is still unclear whether their members are chemically distinguishable from other halo stars in the Milky Way.
Aims: We aim to precisely characterize the chemical properties of the Helmi str…
Inferring the HII region escape fraction of ionizing photons from infrared emission lines in metal-poor star-forming dwarf galaxies
Morisset, C.; Schaerer, D.; Ramambason, L. +8 more
Local metal-poor galaxies stand as ideal laboratories for probing the properties of the interstellar medium (ISM) in chemically unevolved conditions. Detailed studies of this primitive ISM can help gain insights into the physics of the first primordial galaxies that may be responsible for the reionization. Quantifying the ISM porosity to ionizing …
Performance of near-infrared high-contrast imaging methods with JWST from commissioning
Carter, Aarynn L.; Perrin, Marshall D.; Pueyo, Laurent +12 more
The James Webb Space Telescope (JWST) will revolutionize the field of high-contrast imaging and enable both the direct detection of Saturn-mass planets and the characterization of substellar companions in the mid-infrared. While JWST will feature unprecedented sensitivity, angular resolution will be the key factor when competing with ground-based …
Superresolution trends in the ALMA Taurus survey: structured inner discs and compact discs
Tazzari, Marco; Rosotti, Giovanni P.; Clarke, Cathie J. +2 more
The 1.33-mm survey of protoplanetary discs in the Taurus molecular cloud found annular gaps and rings to be common in extended sources (≳ 55AU), when their 1D visibility distributions were fit parametrically. We first demonstrate the advantages and limitations of non-parametric visibility fits for data at the survey's 0.12-arcsec resolution. Then …
First light for GRAVITY Wide. Large separation fringe tracking for the Very Large Telescope Interferometer
Lutz, D.; Förster Schreiber, N. M.; Genzel, R. +114 more
GRAVITY+ is the upgrade for GRAVITY and the Very Large Telescope Interferometer (VLTI) with wide-separation fringe tracking, new adaptive optics, and laser guide stars on all four 8 m Unit Telescopes (UTs) to enable ever-fainter, all-sky, high-contrast, milliarcsecond interferometry. Here we present the design and first results of the first phase …
A Maximum Likelihood Calibration of the Tip of the Red Giant Branch Luminosity from High Latitude Field Giants Using Gaia Early Data Release 3 Parallaxes
Casertano, Stefano; Li, Siyang; Riess, Adam G.
The calibration of the tip of the red giant branch (TRGB) in the I band has a direct role in determinations of the Hubble constant, a subject of recent interest due to the discrepancy between direct and indirect estimates of its value. We present a maximum likelihood method designed to obtain an independent calibration of the brightness of TRGB us…
Orbital and dynamical analysis of the system around HR 8799. New astrometric epochs from VLT/SPHERE and LBT/LUCI
Avenhaus, H.; Marzari, F.; Henning, Th. +45 more
Context. HR 8799 is a young planetary system composed of four planets and a double debris belt. Being the first multi-planetary system discovered with the direct imaging technique, it has been observed extensively since 1998. This wide baseline of astrometric measurements, counting over 50 observations in 20 years, permits a detailed orbital and d…