Search Publications
Searching for Milky Way twins: Radial abundance distribution as a strict criterion
Tautvaišienė, G.; Lara-López, M. A.; Pilyugin, L. S.
We search for Milky Way-like galaxies among a sample of approximately 500 galaxies. The characteristics we considered of the candidate galaxies are the following: stellar mass M⋆, optical radius R25, rotation velocity Vrot, central oxygen abundance (O/H)0, and abundance at the optical radius (O/H)R<…
The metallicity distribution in the core of the Sagittarius dwarf spheroidal: Minimising the metallicity biases
Dalessandro, Emanuele; Mucciarelli, Alessio; Ibata, Rodrigo +7 more
We present the metallicity and radial velocity for 450 bona fide members of the Sagittarius dwarf spheroidal (Sgr dSph) galaxy, measured from high-resolution spectra (R ≃ 18 000) obtained with FLAMES at the VLT. The targets were carefully selected (a) to sample the core of the main body of Sgr dSph while avoiding contamination from the central ste…
Quasars as standard candles. IV. Analysis of the X-ray and UV indicators of the disc-corona relation
Signorini, Matilde; Risaliti, Guido; Lusso, Elisabeta +4 more
Context. A non-linear relation between quasar monochromatic luminosities at 2500 Å and 2 keV holds at all observed redshifts and luminosities, and it has been used to derive quasar distances and to build a Hubble diagram of quasars. The choice of the X-ray and UV indicators has so far been somewhat arbitrary and has typically relied on photometric…
The pristine nature of SMSS 1605−1443 revealed by ESPRESSO
Rebolo, R.; Zapatero Osorio, M. R.; Allende Prieto, C. +20 more
Context. SMSS J160540.18−144323.1 is the carbon-enhanced metal-poor (CEMP) star with the lowest iron abundance ever measured, [Fe/H] = −6.2, which was first reported with the SkyMapper telescope. The carbon abundance is A(C)≈6.1 in the low-C band, as the majority of the stars in this metallicity range. Yet, constraining the isotopic ratio of key s…
Probing the nature of the low state in the extreme ultraluminous X-ray pulsar NGC 5907 ULX1
Salvaterra, R.; Pinto, C.; Israel, G. L. +13 more
NGC 5907 ULX1 is the most luminous ultra-luminous X-ray pulsar (ULXP) known to date, reaching luminosities in excess of 1041 erg s−1. The pulsar is known for its fast spin-up during the on-state. Here, we present a long-term monitoring of the X-ray flux and the pulse period between 2003 and 2022. We find that the source was i…
A type II solar radio burst without a coronal mass ejection
Vainio, R.; Kilpua, E. K. J.; Kumari, A. +2 more
Context. The Sun produces the most powerful explosions in the Solar System, solar flares, which can also be accompanied by large eruptions of magnetised plasma, coronal mass ejections (CMEs). These processes can accelerate electron beams up to relativistic energies through magnetic reconnection processes during solar flares and CME-driven shocks. …
A full transit of v2 Lupi d and the search for an exomoon in its Hill sphere with CHEOPS
Guterman, P.; Alonso, R.; Deleuil, M. +90 more
The planetary system around the naked-eye star v2 Lupi (HD 136352; TOI-2011) is composed of three exoplanets with masses of 4.7, 11.2, and 8.6 Earth masses (M⊕). The TESS and CHEOPS missions revealed that all three planets are transiting and have radii straddling the radius gap separating volatile-rich and volatile-poor super…
Stragglers of the thick disc
Katz, D.; Haywood, M.; Royer, F. +2 more
Young alpha-rich (YAR) stars have been detected in the past as outliers to the local age − [α/Fe] relation. These objects are enhanced in α-elements, but they are apparently younger than typical thick disc stars. Here, we study the global kinematics and chemical properties of YAR giant stars in the APOGEE DR17 survey and show that they have proper…
Probing the timescale of the 1.4 GHz radio emissions as a star formation tracer
Magnelli, B.; Ilbert, O.; Ciesla, L. +3 more
Context. Radio used as a tracer of the star formation rate (SFR) presents enormous advantages because it is not affected by dust and radio sources that are located at the subarcsecond level. The interpretation of the low-frequency 1.4 GHz luminosity is hampered by the difficulty of modeling the paths of cosmic rays in the interstellar medium, howe…
Gaia Focused Product Release: Sources from Service Interface Function image analysis. Half a million new sources in omega Centauri
Prusti, T.; Mazeh, T.; Zucker, S. +400 more
Context. Gaia's readout window strategy is challenged by very dense fields in the sky. Therefore, in addition to standard Gaia observations, full Sky Mapper (SM) images were recorded for nine selected regions in the sky. A new software pipeline exploits these Service Interface Function (SIF) images of crowded fields (CFs), making use of the availa…