Search Publications
Rapid spectral transition of the black hole binary V404 Cygni
Motta, S. E.; Sánchez-Fernández, C.; Alfonso-Garzón, J. +2 more
During the June 2015 outburst of the black hole binary V404 Cyg, rapid changes in the X-ray brightness and spectra were common. The INTEGRAL monitoring campaign detected spectacular Eddington-limited X-ray flares, but also rapid variations at much lower flux levels. On 2015 June 21 at 20 h 50 min, the 3-10 keV JEM-X data as well as simultaneous op…
Strömgren metallicities for intermediate-age and old star clusters
Piatti, Andrés E.
We report results that show that the straightforward star cluster metallicities obtained from Strömgren vby photometry are age-dependent and need to be corrected for further use. This outcome arises from the comparison of [Fe/H] values derived from Strömgren photometry with those metallicities published in the literature for 26 Large and Small Mag…
Is the primary CoRoT target HD 43587 under a Maunder minimum phase?
Barbosa, R.; do Nascimento, J. -D.; Castro, M. +4 more
Context. One of the most enigmatic phenomena related to solar activity is the so-called Maunder minimum phase. It consists in the lowest sunspot count ever registered for the Sun and has not been confirmed for other stars to date. Since the spectroscopic observations of stellar activity at the Mount Wilson Observatory, the solar analog HD 43587 ha…
Evidence for radially independent size growth of early-type galaxies in clusters
Andreon, S.
It is not well understood whether the growth of early-type cluster galaxies proceeds inside-out, outside-in, or at the same pace at all radii. In this work we measured the galaxy size, defined by the radius including 80% of the galaxy light, non-parametrically. We also determined a non-parametric estimate of galaxy light concentration, which measu…
A multi-diagnostic spectral analysis of penumbral microjets
Rouppe van der Voort, Luc; Drews, Ainar
Context. Penumbral microjets (PMJs) are short-lived, jet-like objects found in the penumbra of sunspots. They were first discovered in chromospheric lines and have later also been shown to exhibit signals in transition region (TR) lines. Their origin and manner of evolution is not yet settled.
Aims: We perform a comprehensive analysis of PMJs…
The XXL Survey. XLIII. The quasar radio loudness dichotomy exposed via radio luminosity functions obtained by combining results from COSMOS and XXL-S X-ray selected quasars
Smolčić, V.; Pierre, M.; Leslie, S. +13 more
We studied a sample of 274 radio and X-ray selected quasars (XQSOs) detected in the COSMOS and XXL-S radio surveys at 3 GHz and 2.1 GHz, respectively. This sample was identified by adopting a conservative threshold in X-ray luminosity, LX [2-10 keV] ≥ 1044 erg s-1, selecting only the most powerful quasars. A number…
CzeV1731: The unique doubly eclipsing quadruple system
Wolf, M.; Gazeas, K.; Mašek, M. +14 more
We report the discovery of the relatively bright (V = 10.5 mag), doubly eclipsing 2+2 quadruple system CzeV1731. This is the third known system of its kind, in which the masses are determined for all four stars and both the inner and outer orbits are characterized. The inner eclipsing binaries are well-detached systems moving on circular orbits: p…
A deep X-ray spectral imaging of the bow-shock pulsar wind nebula associated with PSR B1929+10
Takata, J.; Hui, C. Y.; Lin, L. C. C. +3 more
In this work, we study the X-ray bow-shock nebula powered by the mature pulsar PSR B1929+10 using data from XMM-Newton, with an effective exposure of ∼300 ks, offering the deepest investigation of this system thus far. We found the X-ray axial outflow extends as long as ∼8 arc minute behind the proper motion direction, which is a factor of two lon…
Tomography of cool giant and supergiant star atmospheres. III. Validation of the method on VLTI/AMBER observations of the Mira star S Ori
Anderson, Richard I.; Kravchenko, Kateryna; Chiavassa, Andrea +5 more
Context. Asymptotic giant branch (AGB) stars are characterized by substantial mass loss, however the mechanism behind it not yet fully understood. The knowledge of the structure and dynamics of AGB-star atmospheres is crucial to better understanding the mass loss. The recently established tomographic method, which relies on the design of spectral …
Near-ultraviolet detections of four dwarf nova candidates in the globular cluster 47 Tucanae
Wijnands, Rudy; Modiano, David; Parikh, Aastha S.
We investigate near-ultraviolet variability in the Galactic globular cluster (GC) 47 Tucanae (47 Tuc). This work was undertaken within the GC sub-project of the Transient UV Objects project, a programme which aims to find and study transient and strongly variable UV sources. Globular clusters are ideal targets for transient searches because of the…