Search Publications
The star formation history and the nature of the mass-metallicity relation of passive galaxies at 1.0 < z < 1.4 from VANDELS
De Lucia, G.; Marchesini, D.; Nonino, M. +9 more
We derived stellar ages and metallicities [Z/H] for ~70 passive early-type galaxies (ETGs) selected from VANDELS survey over the redshift range 1.0 < z < 1.4 and stellar mass range 10 < log(M*/M⊙) < 11.6. We find significant systematics in their estimates depending on models and wavelength ranges considered. Using…
Bursts from Space: MeerKAT - the first citizen science project dedicated to commensal radio transients
Heywood, Ian; Motta, Sara; Tremou, Evangelia +40 more
The newest generation of radio telescopes is able to survey large areas with high sensitivity and cadence, producing data volumes that require new methods to better understand the transient sky. Here, we describe the results from the first citizen science project dedicated to commensal radio transients, using data from the MeerKAT telescope with w…
A high fidelity Milky Way simulation with Kraken, Gaia-Enceladus, and Sequoia analogues: clues to their accretion histories
Grand, Robert J. J.; Kawata, Daisuke; García-Bethencourt, Guacimara +1 more
Within a simulated Milky Way-like galaxy, we identify and analyse analogues of the Gaia-Enceladus (GE), Kraken, and Sequoia mergers that each matches remarkably well observational results, including in velocity and chemical abundance space, and their distributions in the jz-Energy plane. The Kraken analogue is the earliest merger and ha…
The Gaia alerted fading of the FUor-type star Gaia21elv
Lee, Jeong-Eun; Gromadzki, Mariusz; Ábrahám, Péter +26 more
FU Orionis objects (FUors) are eruptive young stars, which exhibit outbursts that last from decades to a century. Due to the duration of their outbursts, and to the fact that only about two dozens of such sources are known, information on the end of their outbursts is limited. Here we analyse follow-up photometry and spectroscopy of Gaia21elv, a y…
JWST unveils the brown dwarf sequence of 47 Tucanæ
Bedin, L. R.; Nardiello, D.; Griggio, M.
We have developed a technique to restore scientific usage in compromised (publicly available) images collected with the JWST of the Galactic globular cluster NGC 104 (47 Tucanæ). In spite of the degradation and limited data, we were able to recover photometry and astrometry for the coolest stellar objects ever observed within a globular cluster, p…
Surface structure of 45 Hercules: an otherwise unremarkable Ap star with a surprisingly weak magnetic field
Petit, P.; Amarsi, A. M.; Kochukhov, O. +3 more
The origin of magnetic fields and their role in chemical spot formation on magnetic Ap stars is currently not understood. Here, we contribute to solving this problem with a detailed observational characterization of the surface structure of 45 Her, a weak-field Ap star. We find this object to be a long-period, single-lined spectroscopic binary and…
Using shell models to investigate clumping in the WN4 star HD 50896
Hillier, D. John; Dessart, Luc; Flores, Brian L.
The spectra of Wolf-Rayet (WR) stars exhibit strong, broad emission lines that originate in the wind. These winds are radiatively driven and are susceptible to hydrodynamic instabilities that result in the formation of clumps. When modelling spectra of WR stars the volume-filling factor (VFF) approach is usually employed to treat clumpy winds. How…
Carbon-oxygen ultra-massive white dwarfs in general relativity
Córsico, Alejandro H.; Rebassa-Mansergas, Alberto; Althaus, Leandro G. +4 more
We employ the La Plata stellar evolution code, LPCODE, to compute the first set of constant rest-mass carbon-oxygen ultra-massive white dwarf evolutionary sequences for masses higher than 1.29 M⊙ that fully take into account the effects of general relativity on their structural and evolutionary properties. In addition, we employ the LP-…
Tidally induced velocity gradients in the Milky Way dwarf spheroidal satellites
del Pino, Andrés; Aparicio, Antonio; Martínez-García, Alberto Manuel
We present a kinematic study of six dwarf spheroidal galaxies (dSph) satellites of the Milky Way (MW), namely Carina, Draco, Fornax, Sculptor, Sextans, and Ursa Minor. We combine proper motions (PMs) from the Gaia Data Release 3 (DR3) and line-of-sight velocities (vlos) from the literature to derive their 3D internal kinematics and to s…
Photometric and spectroscopic monitoring of YSOs in nearby star-forming regions - I. Eruptive YSOs
Herczeg, Gregory J.; Jose, Jessy; Johnstone, Doug +7 more
Mid-infrared (mid-IR) variability in young stellar objects (YSOs) is driven by several physical mechanisms, which produce a variety of amplitudes and light-curve shapes. One of these mechanisms, variable disc accretion, is predicted by models of episodic accretion to drive secular variability, including in the mid-IR. Because the largest accretion…