Search Publications
Variability and the X-ray/UV ratio of active galactic nuclei
Trevese, D.; Vagnetti, F.; Antonucci, M. +1 more
Context. The observed relation between the X-ray radiation from active galactic nuclei, originating in the corona, and the optical/UV radiation from the disk is usually described by the anticorrelation between the UV to X-ray slope α_ox and the UV luminosity. Many factors can affect this relation, including: i) enhanced X-ray emission associated w…
Surface structure of the CoRoT CP2 target star HD 50773
Donati, J. -F.; Petit, P.; Baudin, F. +15 more
Aims: We compare surface maps of the chemically peculiar star HD 50773 produced with a Bayesian technique and based on high quality CoRoT photometry with those derived from rotation phase resolved spectropolarimetry. The goal is to investigate the correlation of surface brightness with surface chemical abundance distribution and the stellar m…
The Herschel view of star formation in the Rosette molecular cloud under the influence of NGC 2244
Olofsson, G.; Abergel, A.; Hill, T. +43 more
Context. The Rosette molecular cloud is promoted as the archetype of a triggered star-formation site. This is mainly due to its morphology, because the central OB cluster NGC 2244 has blown a circular-shaped cavity into the cloud and the expanding H II-region now interacts with the cloud.
Aims: Studying the spatial distribution of the differe…
Physical and morphological properties of z ~ 3 Lyman break galaxies: dependence on Lyα line emission
Castellano, M.; Pentericci, L.; Fontana, A. +4 more
Aims: We investigate the physical and morphological properties of Lyman break galaxies (LBGs) at redshift ~2.5 to ~3.5, to determine if and how they depend on the nature and strength of the Lyα emission.
Methods: We selected U-dropout galaxies from the z-detected GOODS-MUSIC catalog by adapting the classical Lyman break criteria on the G…
Herschel observations of EXtra-Ordinary Sources (HEXOS): Detection of hydrogen fluoride in absorption towards Orion KL
Menten, K. M.; Martin, P. G.; Murphy, J. A. +52 more
We report a detection of the fundamental rotational transition of hydrogen fluoride in absorption towards Orion KL using Herschel/HIFI. After the removal of contaminating features associated with common molecules (“weeds”), the HF spectrum shows a P-Cygni profile, with weak redshifted emission and strong blue-shifted absorption, associated with th…
Photometry and spectroscopy of GRB 060526: a detailed study of the afterglow and host galaxy of a z = 3.2 gamma-ray burst
Dahle, H.; Covino, S.; Ganesh, S. +59 more
Aims: With this paper we want to investigate the highly variable afterglow light curve and environment of gamma-ray burst (GRB) 060526 at z = 3.221.
Methods: We present one of the largest photometric datasets ever obtained for a GRB afterglow, consisting of multi-color photometric data from the ultraviolet to the near infrared. The data …
Herschel images of NGC 6720: H2 formation on dust grains
Walker, H. J.; Ivison, R. J.; Blommaert, J. A. D. L. +27 more
Herschel PACS and SPIRE images have been obtained of NGC 6720 (the Ring nebula). This is an evolved planetary nebula with a central star that is currently on the cooling track, due to which the outer parts of the nebula are recombining. From the PACS and SPIRE images we conclude that there is a striking resemblance between the dust distribution an…
Bright optical day-side emission from extrasolar planet CoRoT-2b
Snellen, I. A. G.; Burrows, A.; de Mooij, E. J. W.
We present our analysis of the red-channel CoRoT data of extrasolar planet CoRoT-2b. A deep secondary eclipse is detected at a level of 1.02 ± 0.20 × 10-4, which suggests that all of the planet-signal detected previously in white light by Alonso et al. (2009, A&A, 501, L23) originates from the red channel. CoRoT-2b is the coolest ex…
The Herschel Virgo Cluster Survey. IV. Resolved dust analysis of spiral galaxies
Bomans, D. J.; Bianchi, S.; Fritz, J. +27 more
We present a resolved dust analysis of three of the largest angular size spiral galaxies, NGC 4501 and NGC 4567/8, in the Herschel Virgo Cluster Survey (HeViCS) science demonstration field. Herschel has unprecedented spatial resolution at far-infrared wavelengths and with the PACS and SPIRE instruments samples both sides of the peak in the far inf…
The detached dust shells of AQ Andromedae, U Antliae, and TT Cygni
Blommaert, J. A. D. L.; Jean, C.; Regibo, S. +14 more
Detached circumstellar dust shells are detected around three carbon variables using Herschel-PACS. Two of them are already known on the basis of their thermal CO emission and two are visible as extensions in IRAS imaging data. By model fits to the new data sets, physical sizes, expansion timescales, dust temperatures, and more are deduced. A compa…