Search Publications
Analytical shear and flexion of Einasto dark matter haloes
Baes, M.; Frutos-Alfaro, F.; Retana-Montenegro, E.
N-body simulations predict that dark matter haloes are described by specific density profiles on both galactic- and cluster-sized scales. Weak gravitational lensing through the measurements of their first and second order properties, shear and flexion, is a powerful observational tool for investigating the true shape of these profiles. One of the …
A planetary companion around the K giant ɛ Corona Borealis
Lee, B. -C.; Park, M. -G.; Han, I. +2 more
Aims: Our aim is to search for and study the origin of the low-amplitude and long-periodic radial velocity (RV) variations in K giants.
Methods: We present high-resolution RV measurements of K2 giant ɛ CrB from February 2005 to January 2012 using the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at the Bohyunsan Optical Ast…
VLT and Suzaku observations of the Fermi pulsar PSR J1028-5819
Marelli, M.; Razzano, M.; Esposito, P. +4 more
Context. The launch of the Fermi Gamma-ray Space Telescope in 2008 opened new perspectives in the multi-wavelength studies of neutron stars, with more than 100 γ-ray pulsars having since been detected. While most Fermi pulsars had previously been observed in the X-rays with Chandra and XMM-Newton, optical observations with 8 m-class telescopes exi…
Tidal interaction vs. ram pressure stripping effects as seen in X-rays. Hot gas in group and cluster galaxies
Bomans, D. J.; Braine, J.; Ehle, M. +4 more
Context. Cluster and group spiral galaxies are very often affected by their environment. The hot intracluster/intragroup medium (ICM/IGM) and a high galaxy density can lead to perturbations of the galactic interstellar medium (ISM) due to ram pressure and/or tidal interaction effects. In radio polarimetry observations, both phenomena may manifest …
First simultaneous optical/near-infrared imaging of an X-ray selected, high-redshift cluster of galaxies with GROND. The galaxy population of XMMU J0338.7 + 0030 at z = 1.1
Böhringer, H.; Greiner, J.; Pratt, G. W. +28 more
Context. The XMM-Newton Distant Cluster Project is a serendipitous survey for clusters of galaxies at redshifts z ≥ 0.8 based on deep archival XMM-Newton observations. X-ray sources identified as extended are screened against existing optical all-sky surveys for galaxies, in case of candidate high-z clusters followed up with imaging at 4 m-class t…
Direct imaging of a massive dust cloud around R Coronae Borealis
Waters, L. B. F. M.; Jeffers, S. V.; Min, M. +5 more
We present recent polarimetric images of the highly variable star R CrB using ExPo and archival WFPC2 images from the HST. We observed R CrB during its current dramatic minimum where it decreased more than 9 mag due to the formation of an obscuring dust cloud. Since the dust cloud is only in the line-of-sight, it mimics a coronograph allowing the …
The high-field polar RX J1007.5-2017
Burwitz, V.; Beuermann, K.; Schwope, A. D. +2 more
We report optical and X-ray observations of the high-field polar RX J1007.5-2017 performed between 1990 and 2012. It has an orbital period of 208.60 min determined from the ellipsoidal modulation of the secondary star in an extended low state. The spectral flux of the dM3 - secondary star yields a distance of 790 ± 105 pc. At low accretion levels,…
Light echo of V838 Monocerotis: properties of the echoing medium
Tylenda, R.; Kamiński, T.
Context. The light echo phenomenon that accompanied the 2002 eruption of V838 Mon allows one to study the properties of the diffuse dusty matter in the vicinity of the object.
Aims: We are aiming at obtaining estimates of the optical thickness of the circumstellar matter in front of V838 Mon, as well as optical properties of dust grains in th…
From CoRoT 102899501 to the Sun. A time evolution model of chromospheric activity on the main sequence
Deleuil, M.; Fridlund, M.; Gondoin, P. +7 more
Aims: The present study reports measurements of the rotation period of a young solar analogue, estimates of its surface coverage by photospheric starspots and of its chromospheric activity level, and derivations of its evolutionary status. Detailed observations of many young solar-type stars, such as the one reported in the present paper, pro…
Empirical near-infrared colors for low-mass stars and brown dwarfs in the Orion Nebula Cluster. An empirical near-infrared isochrone at ~1 Myr
Robberto, M.; Scandariato, G.; Da Rio, N. +2 more
Context. Current atmospheric and evolutionary models for low-mass stars and brown dwarfs rely on approximate assumptions on the physics of the stellar structure and the atmospheric radiative transfer. This leads to biased theoretical predictions on the photospheric spectral energy distributions of these system, especially when applied to low surfa…