Search Publications
The HR 1614 moving group is not a dissolving cluster
Casagrande, Luca; Feltzing, Sofia; Sahlholdt, Christian L. +3 more
Context. The HR 1614 is an overdensity in velocity space and has for a long time been known as an old (∼2 Gyr) and metal-rich ([Fe/H] ≈ +0.2) nearby moving group that has a dissolving open cluster origin. The existence of such old and metal-rich groups in the solar vicinity is quite unexpected since the vast majority of nearby moving groups are kn…
Visible and near-infrared spectro-interferometric analysis of the edge-on Be star o Aquarii
Meilland, A.; Carciofi, A. C.; Domiciano de Souza, A. +11 more
Aims: We present a detailed visible and near-infrared spectro-interferometric analysis of the Be-shell star o Aquarii from quasi-contemporaneous CHARA/VEGA and VLTI/AMBER observations.
Methods: We analyzed spectro-interferometric data in the Hα (VEGA) and Brγ (AMBER) lines using models of increasing complexity: simple geometric models, k…
First spectroscopic study of ionised gas emission lines in the extreme low surface brightness galaxy Malin 1
Koda, J.; Chemin, L.; Boselli, A. +7 more
Context. Malin 1 is the largest known low surface brightness (LSB) galaxy, the archetype of so-called giant LSB galaxies. The structure and origin of such galaxies are still poorly understood, especially because of the lack of high-resolution kinematics and spectroscopic data.
Aims: We use emission lines from spectroscopic observations of Mal…
Carina High-contrast Imaging Project for massive Stars (CHIPS). I. Methodology and proof of concept on QZ Car (≡ HD 93206)
Absil, O.; De Ridder, J.; Zinnecker, H. +13 more
Context. Massive stars like company. However, low-mass companions have remained extremely difficult to detect at angular separations (ρ) smaller than 1″ (approx. 1000-3000 au, considering the typical distance to nearby massive stars) given the large brightness contrast between the companion and the central star. Constraints on the low-mass end of …
Collinder 135 and UBC 7: A physical pair of open clusters
Reffert, Sabine; Berczik, Peter; Just, Andreas +7 more
Context. Given the closeness of the two open clusters
Aims: We aim to recover the present-day stellar membership in the open clusters
A surprise in the updated list of stellar perturbers of long-period comet motion
Dybczyński, Piotr A.; Wysoczańska, Rita; Polińska, Magdalena
Context. The second Gaia data release (Gaia DR2) provided us with the precise five-parameter astrometry for 1.3 billion of sources. As stars passing close to the Solar System are thought to influence the dynamical history of long-period comets, we update and extend the list of stars that could potentially perturb the motion of these comets.
A…
Four microlensing planets with faint-source stars identified in the 2016 and 2017 season data
Han, Cheongho; Udalski, Andrzej; Lee, Chung-Uk +34 more
Aims: Microlensing planets occurring on faint-source stars can escape detection due to their weak signals. Occasionally, detections of such planets are not reported due to the difficulty of extracting high-profile scientific issues on the detected planets.
Methods: For the solid demographic census of microlensing planetary systems based …
A Compton-thick nucleus in the dual active galactic nuclei of Mrk 266
Inami, H.; Iwasawa, K.; Charmandaris, V. +6 more
We present the results from our analysis of NuSTAR data of the luminous infrared galaxy Mrk 266, which contains two nuclei, south-western (SW) and north-eastern (NE), which were resolved in previous Chandra imaging. Combining this with the Chandra data, we intepret the hard X-ray spectrum obtained from a NuSTAR observation to result from a steeply…
Water megamaser emission in hard X-ray selected AGN
Ubertini, P.; Malizia, A.; Bassani, L. +4 more
Context. Water megamaser emission at 22 GHz has proven to be a powerful tool for astrophysical studies of active galactic nuclei (AGN) because it allows an accurate determination of the mass of the central black hole and of the accretion disc geometry and dynamics. However, after searches among thousands of galaxies, only about 200 of them have sh…
Evolution of supersonic downflows in a sunspot
Mathioudakis, M.; Krishna Prasad, S.; Nelson, C. J.
Context. Supersonic downflows have been observed in transition region spectra above numerous sunspots, however, little research has been conducted to date into how persistent these signatures are within sunspots on timescales longer than a few hours.
Aims: We aim to analyse the lead sunspot of AR 12526 to infer the properties and evolution of…