Search Publications
Calibrating the metallicity of M dwarfs in wide physical binaries with F-, G-, and K-primaries - II: carbon, oxygen, and odd-Z iron-peak abundances of the primary stars
Caballero, J. A.; Montes, D.; Duque-Arribas, C. +1 more
Detailed chemical composition of stars is of prime interest for a range of topics in modern stellar astrophysics, such as the chemical evolution of the Galaxy or the formation, composition, and structure of exoplanets. In this work, we derive the C and O abundances and update Sc, V, Mn, and Co abundances considering hyperfine structure effects and…
Exploration of Halo Substructures in Integrals-of-motion Space with Gaia Data Release 3
Ye, Dashuang; Du, Cuihua; Deng, Mingji +2 more
Using kinematic data from the Gaia Data Release 3 catalog, along with metallicity estimates robustly derived from Gaia BP/RP spectra, we have explored the Galactic stellar halo in search of both known and potentially new substructures. By applying the Hierarchical Density-Based Spatial Clustering of Applications with Noise clustering algorithm in …
The MIRI/MRS Library. I. Empirically correcting detector charge migration in unresolved sources
Gordon, Karl D.; Law, David R.; Patapis, Polychronis +7 more
Context. The James Webb Space Telescope (JWST) has been collecting scientific data for over two years now. The Medium Resolution Spectrometer (MRS) of the Mid-InfraRed Instrument (MIRI) has been one of the telescope's most popular modes, and has already produced ground-breaking results. Scientists are now looking deeper into the data for new excit…
The merger of hard binaries in globular clusters as the primary channel for the formation of second-generation stars
Kravtsov, Valery; Calderón, Francisco A.; Dib, Sami
We have recently presented observational evidence which suggests that the origin of the second-generation (G2) stars in globular clusters (GCs) is due to the binary-mediated collision of primordial (G1) low-mass main-sequence (MS) stars. This mechanism avoids both the mass budget problem and the need of external gas for dilution. Here, we report o…
NGC 5474 X-1: A neutron star ultraluminous X-ray source in an old stellar cluster?
Fabrika, Sergei; Atapin, Kirill; Vinokurov, Alexander +4 more
We present an optical and X-ray study of the ultraluminous X-ray source (ULX) NGC 5474 X-1. The X-ray spectrum taken during the bright state of the source (LX ~ 2 × 1040 erg s-1) shows signatures of a broad absorption line at ≃ 8 keV, which may be a cyclotron resonant scattering feature. This implies that this syst…
La Silla-QUEST RR Lyrae star survey II: the Crater II tidal streams
Girard, T.; Baltay, C.; Howard, R. +5 more
We describe photometry improvements in the La Silla-Quest RR Lyrae star (RRLS) survey that enable it to reach distances from the Sun (d⊙) ~140 kpc. We report the results of surveying ~300 deg2 of sky around the large, low-surface-brightness Crater II dwarf spheroidal galaxy. At d⊙ >80 kpc, we find a large overde…
A CIGALE module tailored (not only) for low-luminosity active galactic nuclei
Alexander, D. M.; Lapi, A.; Comastri, A. +17 more
The spectral energy distribution (SED) of low-luminosity active galactic nuclei (LLAGN) presents unique challenges as the emission from these objects is comparable to the radiation from their host galaxy and the accretion physics involved is particularly complex. This study introduces a novel CIGALE module specifically designed to address these ch…
HD 7977 and its possible influence on Solar System bodies
Dybczyński, Piotr A.; Królikowska, Małgorzata; de Bruijne, Jos +5 more
Context. In the latest Gaia third data release, one can find extremely small proper motion components for the star HD 7977. This, together with the radial velocity measurement lead to the conclusion that this star passed very close to the Sun in the recent past.
Aims: Such a very close approach of a one solar mass star must have resulted in n…
XMM–NuSTAR Observation and Multiwavelength Spectral Energy Distribution Modeling of Blazar 4FGL J1520.8–0348
Ajello, M.; Tramacere, A.; Marcotulli, L. +1 more
Active galactic nuclei (AGNs) can power relativistic jets, which are called blazars when pointed close to our line of sight. Depending on the presence or absence of emission lines in their optical spectra, blazars are categorized into flat spectrum radio quasars (FSRQs) or BL Lacertae (BL Lac) objects. According to the "blazar sequence," as synchr…
Investigating the extinction and magnetic field geometry in the Bok globule CB26
Medhi, B. J.; Mazarbhuiya, A. M.; Das, H. S. +2 more
This study investigates the extinction properties, dust distribution, and magnetic field characteristics of the CB26 cloud. Extinction mapping, derived from near-infrared photometry, reveals a good correlation with the dust distribution, as traced by Herschel1SPIRE 500