Search Publications
The Pristine survey: XXV. The very metal-poor Galaxy: Chemodynamics through the follow-up of the Pristine-Gaia synthetic catalogue
Massana, Pol; Sestito, Federico; Ibata, Rodrigo A. +27 more
Context. The Pristine-Gaia synthetic catalogue of reliable photometric metallicities makes use of spectrophotometric information from Gaia DR3 XP spectra to calculate metallicity-sensitive CaHK magnitudes, which in turn provides photometric metallicities for ~30 million FGK stars using the Pristine survey model and the survey's training sample. Ai…
The first all-sky survey of star-forming galaxies with eROSITA: Scaling relations and a population of X-ray luminous starbursts
Haberl, F.; Ptak, A.; Zezas, A. +12 more
Context. In this work, we present the results from a study of X-ray normal galaxies, that is, galaxies not harbouring active galactic nuclei (AGN), using data from the first complete all-sky scan of the eROSITA X-ray survey (eRASS1) obtained with eROSITA on board the Spectrum-Roentgen-Gamma observatory. eRASS1 provides the first unbiased X-ray cen…
Uncovering the invisible: A study of Gaia18ajz, a candidate black hole revealed by microlensing
Mróz, P.; Gromadzki, M.; Rybicki, K. +30 more
Context. Identifying black holes is essential for our understanding of the development of stars and can reveal novel principles of physics. Gravitational microlensing provides an exceptional opportunity to examine an undetectable population of black holes in the Milky Way. In particular, long-lasting events are likely to be associated with massive…
Eppur si muove: Evidence of disc precession or a sub-milliparsec SMBH binary in the QPE-emitting galaxy GSN 069
Miniutti, G.; Giustini, M.; Arcodia, R. +8 more
X-ray quasi-periodic eruptions (QPEs) are intense soft X-ray bursts from the nuclei of nearby low-mass galaxies typically lasting about one hour and repeating every few hours. Their physical origin remains a matter of debate, although so-called impact models appear promising. These models posit a secondary orbiting body piercing through the accret…
Discovery of polarized X-ray emission from the accreting millisecond pulsar SRGA J144459.2–604207
Coti Zelati, Francesco; Salmi, Tuomo; Papitto, Alessandro +22 more
We report the discovery of polarized X-ray emission from an accreting millisecond pulsar. During a 10-day-long coverage of the February 2024 outburst of SRGA J144459.2‑604207, the Imaging X-ray Polarimetry Explorer (IXPE) detected an average polarization degree of the 2–8 keV emission of 2.3%±0.4% at an angle of 59° ±6° (east of north; the uncerta…
Dynamical confirmation of a black hole in the X-ray transient Swift J1727.8‑1613
Armas Padilla, M.; Mata Sánchez, D.; Muñoz-Darias, T. +3 more
The X-ray transient Swift J1727.8‑1613 ended its 10-month discovery outburst in June of 2024, when it reached an optical brightness comparable to pre-discovery magnitudes. With the aim of performing a dynamical study, we launched an optical spectroscopy campaign with the GTC telescope. We detected the companion star and constructed its radial velo…
Euclid preparation: LVIII. Detecting extragalactic globular clusters in the Euclid survey
Cimatti, A.; Ilbert, O.; Baccigalupi, C. +270 more
Extragalactic globular clusters (EGCs) are an abundant and powerful tracer of galaxy dynamics and formation, and their own formation and evolution is also a matter of extensive debate. The compact nature of globular clusters means that they are hard to spatially resolve and thus study outside the Local Group. In this work we have examined how well…
Investigating changing-look active galactic nuclei with long-term optical and X-ray observations
Diaz, Y.; Ricci, C.; Koss, M. +7 more
Context. Broad emission lines in the UV/optical spectra of changing-look active galactic nuclei (CLAGNs) appear and disappear on timescales of months to decades. Aims. We investigate how changing-look (CL) transitions depend on several active galactic nucleus (AGN) parameters, such as the accretion rate, obscuration properties, and black hole mass…
Abundance ties: Nephele and the globular cluster population accreted with ω Cen: Based on APOGEE DR17 and Gaia EDR3
Ryde, N.; Casamiquela, L.; Haywood, M. +8 more
Context. The peculiar Galactic globular cluster ω Centauri (NGC 5139) has drawn attention for its unique features, such as an unusually high stellar mass compared to other Galactic globular clusters and a broad distribution of chemical elements. These features have led to the hypothesis that ω Centauri might be the nuclear remnant of an ancient dw…
The kinematics of 30 Milky Way globular clusters and the multiple stellar populations within
Cabrera-Ziri, I.; Hilker, M.; Carbajo-Hijarrubia, J. +5 more
Aims. The spectroscopic and photometric classification of multiple stellar populations (MPs) in Galactic globular clusters (GCs) has enabled comparisons between contemporary observations and formation theories regarding the initial spatial configurations of the MPs. However, the kinematics of these MPs is an aspect that requires more attention. We…