Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>In the first billion years after its formation, the Galaxy underwent several mergers with dwarf satellites of various masses. The debris of Gaia-Sausage/Enceladus (GSE), the galaxy responsible for the last significant merger of the Milky Way, dominates the inner halo and has been suggested to be the progenitor of both the Hercules-Aquila Cloud (HAC) and Virgo Overdensity (VOD). We combine SEGUE, APOGEE, Gaia, and <jats:monospace>StarHorse</jats:monospace> distances to characterize the chemodynamical properties and verify the link between HAC, VOD, and GSE. We find that the orbital eccentricity distributions of the stellar overdensities and GSE are comparable. We also find that they have similar, strongly peaked, metallicity distribution functions, reinforcing the hypothesis of common origin. Furthermore, we show that HAC and VOD are indistinguishable from the prototypical GSE population within all chemical-abundance spaces analyzed. All these evidences combined provide a clear demonstration that the GSE merger is the main progenitor of the stellar populations found within these halo overdensities.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present the discovery of a wide retrograde moving group in the disk plane of the Milky Way using action-angle coordinates derived from the Gaia DR3 catalog. The structure is identified from a sample of its members that are currently almost at the pericenter of their orbit and are passing through the solar neighborhood. The motions of the stars in this group are highly correlated, indicating that the system is probably not phase mixed. With a width of at least 1.5 kpc and with a probable intrinsic spread in metallicity, this structure is most likely the wide remnant of a tidal stream of a disrupted ancient dwarf galaxy (age ∼12 Gyr, 〈[Fe/H]〉 ∼ −1.74). The structure presents many similarities (e.g., in energy, angular momentum, metallicity, and eccentricity) with the Sequoia merging event. However, it possesses extremely low vertical action <jats:italic>J</jats:italic> <jats:sub> <jats:italic>z</jats:italic> </jats:sub> <jats:italic>,</jats:italic> which makes it unique even among Sequoia dynamical groups. As the low <jats:italic>J</jats:italic> <jats:sub> <jats:italic>z</jats:italic> </jats:sub> may be attributable to dynamical friction, we speculate that these stars may be the remnants of the dense core of the Sequoia progenitor.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Companions at subarcsecond separation from young stars are difficult to image. However, their presence can be inferred from the perturbations they create in the dust and gas of protoplanetary disks. Here we present a new interpretation of SPHERE polarized observations that reveal the previously detected inner spiral in the disk of HD 100546. The spiral coincides with a newly detected <jats:sup>12</jats:sup>CO inner spiral and the previously reported CO emission Doppler flip, which has been interpreted as the signature of an embedded protoplanet. Comparisons with hydrodynamical models indicate that this Doppler flip is instead the kinematic counterpart of the spiral, which is likely generated by an inner companion inside the disk cavity.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Protostellar outflows are one of the most outstanding features of star formation. Observational studies over the last several decades have successfully demonstrated that outflows are ubiquitously associated with low- and high-mass protostars in solar-metallicity Galactic conditions. However, the environmental dependence of protostellar outflow properties is still poorly understood, particularly in the low-metallicity regime. Here we report the first detection of a molecular outflow in the Small Magellanic Cloud with 0.2 <jats:italic>Z</jats:italic> <jats:sub>⊙</jats:sub>, using Atacama Large Millimeter/submillimeter Array observations at a spatial resolution of 0.1 pc toward the massive protostar Y246. The bipolar outflow is nicely illustrated by high-velocity wings of CO(3–2) emission at ≳15 km s<jats:sup>−1</jats:sup>. The evaluated properties of the outflow (momentum, mechanical force, etc.) are consistent with those of the Galactic counterparts. Our results suggest that the molecular outflows, i.e., the guidepost of the disk accretion at the small scale, might be universally associated with protostars across the metallicity range of ∼0.2–1 <jats:italic>Z</jats:italic> <jats:sub>⊙</jats:sub>.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Super-metal-rich (SMR) stars in the solar neighborhood are thought to be born in the inner disk and come to their present location by radial migration, which is most intense at the corotation resonance (CR) of the Galactic bar. In this work, we show evidence for the CR origin of SMR stars in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope and Gaia by detecting six ridges and undulations in the <jats:italic>ϕ</jats:italic> versus <jats:italic>L</jats:italic> <jats:sub>z</jats:sub> space coded by median <jats:italic>V</jats:italic> <jats:sub>R</jats:sub>, following a similar slope of −8 km s<jats:sup>−1</jats:sup> kpc deg<jats:sup>−1</jats:sup>. The slope is predicted by Monario et al.'s model for CR of a large and slow Galactic bar. For the first time, we show the variation in the angular momentum with azimuths from −10° to 20° for two outer and broad undulations with negative <jats:italic>V</jats:italic> <jats:sub>R</jats:sub> around − 18 km s<jats:sup>−1</jats:sup> following this slope. The wave-like pattern with large amplitude outside CR and a wide peak of the second undulation indicate that minor merger of the Sagittarius dwarf galaxy with the disk might play a role besides the significant impact of the CR of the Galactic bar.</jats:p>