Search Publications
The eROSITA Final Equatorial-Depth Survey (eFEDS). The Stellar Counterparts of eROSITA sources identified by machine learning and Bayesian algorithms
Schmitt, J. H. M. M.; Salvato, M.; Czesla, S. +3 more
Stars are ubiquitous X-ray emitters and will be a substantial fraction of the X-ray sources detected in the on-going all-sky survey performed by the eROSITA instrument aboard the Spectrum Roentgen Gamma (SRG) observatory. We use the X-ray sources in the eROSITA Final Equatorial-Depth Survey (eFEDS) field observed during the SRG performance verific…
Diffuse Galactic emission spectrum between 0.5 and 8.0 MeV
Calore, Francesca; Siegert, Thomas; Serpico, Pasquale D. +2 more
The last measurement of the diffuse emission spectrum of the Milky Way in the megaelectronvolt (MeV) photon energy range was performed by CGRO/COMPTEL more than 20 yr ago. We report a new analysis with the spectrometer SPI aboard INTEGRAL in the band 0.5-8.0 MeV, finally superseding the signal-to-noise ratio (S/N) of the historic observations. Thi…
Discovery of a thin lithium plateau among metal-poor red giant branch stars
Salaris, M.; Bonifacio, P.; Spite, M. +5 more
The surface lithium abundance, A(Li), of warm metal-poor dwarf stars exhibits a narrow plateau down to [Fe/H] ~ −2.8 dex, while at lower metallicities the average value drops by 0.3 dex with a significant star-by-star scatter (called `lithium meltdown'). This behaviour is in conflict with predictions of standard stellar evolution models calculated…
TOI-2257 b: A highly eccentric long-period sub-Neptune transiting a nearby M dwarf
Bouchy, F.; Queloz, D.; Stern, D. +64 more
Context. Thanks to the relative ease of finding and characterizing small planets around M-dwarf stars, these objects have become cornerstones in the field of exoplanet studies. The current paucity of planets in long-period orbits around M dwarfs makes such objects particularly compelling as they provide clues about the formation and evolution of t…
A first estimate of the Milky Way dark matter halo spin
Buck, Tobias; Macciò, Andrea V.; Obreja, Aura
The spin, or normalized angular momentum λ, of dark matter halos in cosmological simulations follows a log normal distribution and has little correlation with galaxy observables such as stellar masses or sizes. There is currently no way to infer the λ parameter of individual halos hosting observed galaxies. Here, we present a first attempt to meas…
Mapping Milky Way disk perturbations in stellar number density and vertical velocity using Gaia DR3
Widmark, A.; Widrow, L. M.; Naik, A.
We have mapped the number density and mean vertical velocity of the Milky Way's stellar disk out to roughly two kiloparsecs from the Sun using Gaia Data Release 3 (DR3) and complementary photo-astrometric distance information from StarHorse. For the number counts, we carefully masked spatial regions that are compromised by open clusters, great dis…
The origin of close massive binaries in the M17 star-forming region
Sana, H.; Frost, A. J.; Reggiani, M. +5 more
Context. Spectroscopic multiplicity surveys of O stars in young clusters and OB associations have revealed that a large portion (∼70%) of these massive stars (Mi > 15 M⊙) belong to close and short-period binaries (with a physical separation of less than a few astronomical units). Follow-up VLT(I) high-angular-resolution ob…
FEEDBACK from the NGC 7538 H II region
Schneider, N.; Beuther, H.; Tielens, A. G. G. M. +10 more
Context. The interaction of expanding H II regions with their environmental clouds is one of the central questions driving the Stratospheric Observatory for Infrared Astronomy (SOFIA) legacy program FEEDBACK.
Aims: We want to understand the interaction of the prototypical NGC 7538 H II region with the neighboring molecular cloud hosting sever…
Atomic and molecular gas from the epoch of reionisation down to redshift 2
Ciardi, Benedetta; Péroux, Céline; Maio, Umberto
Context. Cosmic gas makes up about 90% of the baryonic matter in the Universe and H2 molecule is the most tightly linked to star formation.
Aims: In this work we study cold neutral gas, its H2 component at different epochs, and corresponding depletion times.
Methods: We perform state-of-the-art hydrodynamic simulati…
J-PLUS: Searching for very metal-poor star candidates using the SPEEM pipeline
Sobral, David; Lee, Young Sun; Placco, Vinicius M. +25 more
Context. We explore the stellar content of the Javalambre Photometric Local Universe Survey (J-PLUS) Data Release 2 and show its potential for identifying low-metallicity stars using the Stellar Parameters Estimation based on Ensemble Methods (SPEEM) pipeline.
Aims: SPEEM is a tool used to provide determinations of atmospheric parameters for …