Search Publications
H I studies of extremely metal-poor dwarfs in voids - I
Pustilnik, Simon A.; Kurapati, Sushma; Egorova, Evgeniya S.
We present and discuss the results of the Giant Metrewave Radio Telescope H I 21-cm line mapping for five isolated low-mass (M$_{\rm bary}$$\sim$(2-8)$\times 10^7$ M$\odot$) eXtremely Metal Poor dwarfs [12+$\log$(O/H) = 7.13-7.28], selected from the nearby void galaxy sample. All the studied void dwarfs show disturbed morphology in the H I maps wi…
TOI-757 b: an eccentric transiting mini-Neptune on a 17.5-d orbit
Alonso, R.; Bouchy, F.; Deleuil, M. +129 more
We report the spectroscopic confirmation and fundamental properties of TOI$-$757 b, a mini$-$Neptune on a 17.5$-$d orbit transiting a bright star ($V\, =\, 9.7$ mag) discovered by the TESS mission. We acquired high$-$precision radial velocity measurements with the HARPS, ESPRESSO, and PFS spectrographs to confirm the planet detection and determine…
A network of cooler white dwarfs as infrared standards for flux calibration
Sahu, Snehalata; Bohlin, Ralph C.; Gentile Fusillo, Nicola Pietro +6 more
The accurate flux calibration of observational data is vital for astrophysics and cosmology because absolute flux uncertainties of stellar standards propagate into scientific results. With the ever higher precision achieved by telescopic missions (e.g. JWST) in the infrared (IR), suitable calibrators are required for this regime. The basis of the …
Quasi-isotropic UV emission in the ULX NGC 1313 X-1
Castro Segura, N.; Gúrpide, A.
A major prediction of most super-Eddington accretion theories is the presence of anisotropic emission from supercritical discs, but the degree of anisotropy and its dependence on energy remain poorly constrained observationally. A key breakthrough allowing to test such predictions was the discovery of high-excitation photoionized nebulae around ul…
Unipolar solar flares as a manifestation of 'topological' magnetic reconnection
Dumin, Yurii V.; Somov, Boris V.
Solar flares - the most prominent manifestation of solar activity - typically manifest themselves as a single or a set of luminous arcs (magnetic flux tubes) rooted in regions of opposite polarity in the photosphere. However, a careful analysis of archival data from the Hinode satellite reveals occasional surprising cases of flaring arcs whose foo…
Modelling stellar irradiances I: the transition regions of FGKM stars
Del Zanna, G.; Deliporanidou, E.
We employed advanced ionization equilibrium models that we developed in Dufresne et al. (2024), which include charge transfer and density effects, to model UV stellar irradiances for a sample of stars. Our sample includes
Evidence for a black hole in the historical X-ray transient A 1524-61 (= KY TrA)
Armas Padilla, M.; Monelli, M.; Muñoz-Darias, T. +5 more
We present Very Large Telescope spectroscopy, high-resolution imaging, and time-resolved photometry of KY TrA, the optical counterpart to the X-ray binary A 1524-61. We perform a refined astrometry of the field, yielding improved coordinates for KY TrA and the field star interloper of similar optical brightness that we locate 0.64 ± 0.04 arcsec SE…
Disentanglement of the chemodynamical assembly: mapping the Milky Way discs
Teixeira, Ramachrisna; Cantelli, Elvis
The formation and structure of the Milky Way have a fundamental role in our understanding of the universe and its evolution, and thanks to the Gaia mission and large spectroscopic surveys, we live an exceptional moment of data availability, allowing us to trace the building blocks of the Galactic disc and their relations. In this sense, we propose…
The variable radio jet of the accreting neutron star the Rapid Burster
Degenaar, N.; Maccarone, T.; Miller-Jones, J. C. A. +5 more
The Rapid Burster is a unique neutron star low-mass X-ray binary system, showing both thermonuclear v-I and accretion-driven Type-II X-ray bursts. Recent studies have demonstrated how coordinated observations of X-ray and radio variability can constrain jet properties of accreting neutron stars - particularly when the X-ray variability is dominate…
A path towards constraining the evolution of the interstellar medium and outflows in the Milky Way using APOGEE
Ting, Yuan-Sen; Frankel, Neige; Sharda, Piyush
In recent years, the study of the Milky Way has significantly advanced due to extensive spectroscopic surveys of its stars, complemented by astroseismic and astrometric data. However, it remains disjoint from recent advancements in understanding the physics of the Galactic interstellar medium (ISM). This paper introduces a new model for the chemic…