Search Publications
A chemical inventory of the S-type AGB star χ Cygni based on Herschel/HIFI observations of circumstellar line emission. The importance of non-LTE chemical processes in a dynamical region
Olofsson, H.; Justtanont, K.; de Koter, A. +5 more
Context. S-type AGB stars (C/O ≈ 1) are thought to be transition objects from M-type (O-rich) AGB stars to carbon stars and as such are interesting objects in themselves. Of particular interest is to determine accurate circumstellar properties and molecular abundances, due to their predicted sensitivity to the photospheric C/O-ratio.
Aims: Pr…
Suzaku observation of the transient X-ray pulsar GRO J1008-57
Paul, Biswajit; Naik, Sachindra; Vadawale, Santosh V. +1 more
We report the timing and broad-band spectral properties of the Be transient high-mass X-ray binary pulsar GRO J1008-57 using a Suzaku observation in the declining phase of its 2007 November and December outbursts. Pulsations with a period of 93.737 s were clearly detected in the light curves of the pulsar up to the 80-100 keV energy band. The puls…
A Reconnection-driven Rarefaction Wave Model for Coronal Outflows
Aulanier, G.; Del Zanna, G.; Bradshaw, S. J.
We conduct numerical experiments to determine whether interchange reconnection at high altitude coronal null points can explain the outflows observed as blueshifts in coronal emission lines at the boundaries between open and closed magnetic field regions. In this scenario, a strong, post-reconnection pressure gradient forms in the field-aligned di…
The ACS Fornax Cluster Survey. IV. Deprojection of the Surface Brightness Profiles of Early-type Galaxies in the Virgo and Fornax Clusters: Investigating the "Core/Power-law Dichotomy"
Jordán, Andrés; Infante, Leopoldo; Tonry, John L. +8 more
Although early observations with the Hubble Space Telescope (HST) pointed to a sharp dichotomy among early-type galaxies in terms of the logarithmic slope γ' of their central surface brightness profiles, several studies in the past few years have called this finding into question. In particular, recent imaging surveys of 143 early-type galaxies be…
The debris disk host star HD 61005: a member of the Argus association?
Alcalá, J. M.; Lanzafame, A. C.; Brugaletta, E. +6 more
Context. HD 61005 is a nearby young solar type star that shows a large infrared excess due to a debris disk. The disk has been recently imaged from ground and space, with indications of several components. Some characteristics of the disk suggest the presence of planetary companions around the star, that remain undetected in deep adaptive optics i…
The influence of binarity on dust obscuration events in the planetary nebula M 2-29 and its analogues
Rauch, T.; Udalski, A.; Cohen, M. +8 more
The central star of the planetary nebula (CSPN) M 2-29 shows an extraordinary R Coronae Borealis-like fading event in its optical lightcurve. The only other CSPN to show these events are CPD-56°8032 (Hen 3-1333) and V651 Mon (NGC 2346). Dust cloud formation in the line of sight appears responsible but the exact triggering mechanism is not well und…
Using the Sun to estimate Earth-like planets detection capabilities . III. Impact of spots and plages on astrometric detection
Meunier, N.; Lagrange, A. -M.; Desort, M. +1 more
Aims: Stellar activity is a potentially important limitation to the detection of low-mass extrasolar planets with indirect methods (radial velocity, photometry, astrometry). In previous papers, using the Sun as a proxy, we investigated the impact of stellar activity (spots, plages, convection) on the detectability of an Earth-mass planet in t…
The Binary Fraction in the Globular Cluster M10 (NGC 6254): Comparing Core and Outer Regions
Dalessandro, E.; Beccari, G.; Ferraro, F. R. +3 more
We study the binary fraction of the globular cluster M10 (NGC 6254) as a function of the radius from the cluster core to the outskirts, by means of a quantitative analysis of the color distribution of stars relative to the fiducial main sequence. By taking advantage of two data sets, acquired with the Advanced Camera for Survey and the Wide Field …
The effects of X-ray absorption variability in NGC 4395
Nardini, E.; Risaliti, G.
We present a new X-ray analysis of the dwarf Seyfert galaxy NGC 4395, based on two archival XMM-Newton and Suzaku observations. This source is well known for a series of remarkable properties: one of the smallest estimated black hole masses among active galactic nuclei (AGN) (of the order of ∼105 M⊙), intense flux variability…
H II Region Luminosity Function of the Interacting Galaxy M51
Hwang, Narae; Lee, Myung Gyoon; Lee, Jong Hwan
We present a study of H II regions in M51 using the Hubble Space Telescope Advanced Camera for Surveys images taken as part of the Hubble Heritage Program. We have cataloged about 19,600 H II regions in M51 with Hα luminosity in the range of L = 1035.5-1039.0 erg s-1. The Hα luminosity function of H II regions (H I…