Search Publications
Multidimensional Bayesian membership analysis of the Sco OB2 moving group
Ireland, M. J.; Rizzuto, A. C.; Robertson, J. G.
We present a new high-mass membership of the nearby Sco OB2 association based on Hipparcos positions, proper motions and parallaxes, and radial velocities taken from the 2nd Catalogue of Radial Velocities with Astrometric Data (CRVAD-2). The Bayesian membership selection method developed makes no distinction between subgroups of Sco OB2 and utiliz…
Planck early results. XIII. Statistical properties of extragalactic radio sources in the Planck Early Release Compact Source Catalogue
Kneissl, R.; Miville-Deschênes, M. -A.; Bernard, J. -P. +201 more
The data reported in Planck's Early Release Compact Source Catalogue (ERCSC) are exploited to measure the number counts (dN/dS) of extragalactic radio sources at 30, 44, 70, 100, 143 and 217 GHz. Due to the full-sky nature of the catalogue, this measurement extends to the rarest and brightest sources in the sky. At lower frequencies (30, 44, and 7…
Secular Evolution and a Non-evolving Black-hole-to-galaxy Mass Ratio in the Last 7 Gyr
Koekemoer, Anton M.; Trump, Jonathan R.; Jahnke, Knud +6 more
We present new constraints on the ratio of black hole (BH) mass to total galaxy stellar mass at 0.3 < z < 0.9 for a sample of 32 type-1 active galactic nuclei (AGNs) from the XMM-COSMOS survey covering the range M BH ~ 107.2 - 8.7 M sun. Virial M BH estimates based on Hβ are available from the COSM…
Chandra ACIS Survey of X-ray Point Sources in 383 Nearby Galaxies. I. The Source Catalog
Liu, Jifeng
The Chandra data archive is a treasure for various studies, and in this paper we exploit this valuable resource to study the X-ray point source populations in nearby galaxies. By 2007 December 14, 383 galaxies within 40 Mpc with isophotal major axis above 1 arcmin had been observed by 626 public ACIS observations, most of which were for the first …
The Martian Atmospheric Boundary Layer
Spiga, A.; Vázquez, L.; Määttänen, A. +10 more
The planetary boundary layer (PBL) represents the part of the atmosphere that is strongly influenced by the presence of the underlying surface and mediates the key interactions between the atmosphere and the surface. On Mars, this represents the lowest 10 km of the atmosphere during the daytime. This portion of the atmosphere is extremely importan…
Sulfur depletion in dense clouds and circumstellar regions. I. H2S ice abundance and UV-photochemical reactions in the H2O-matrix
Muñoz Caro, G. M.; Jiménez-Escobar, A.
Aims: This work aims to study the unexplained sulfur depletion observed toward dense clouds and protostars.
Methods: We made simulation experiments of the UV-photoprocessing and sublimation of H2S and H2S:H2O ice in dense clouds and circumstellar regions, using the InterStellar Astrochemistry Chamber (ISA…
Numerical Investigation of a Coronal Mass Ejection from an Anemone Active Region: Reconnection and Deflection of the 2005 August 22 Eruption
Gombosi, T. I.; Shibata, K.; Lugaz, N. +3 more
We present a numerical investigation of the coronal evolution of a coronal mass ejection (CME) on 2005 August 22 using a three-dimensional thermodynamic magnetohydrodynamic model, the space weather modeling framework. The source region of the eruption was anemone active region (AR) 10798, which emerged inside a coronal hole. We validate our modele…
Constraints on turbulent velocity broadening for a sample of clusters, groups and elliptical galaxies using XMM-Newton
Fabian, A. C.; Sanders, J. S.; Smith, R. K.
Using the width of emission lines in XMM-Newton Reflection Grating Spectrometer spectra, we place direct constraints on the turbulent velocities of the X-ray emitting medium in the cores of 62 galaxy clusters, groups and elliptical galaxies. We find five objects where we can place an upper limit on the line-of-sight broadening of 500 km s-1
Using a Differential Emission Measure and Density Measurements in an Active Region Core to Test a Steady Heating Model
Winebarger, Amy R.; Warren, Harry P.; Kashyap, Vinay L. +2 more
The frequency of heating events in the corona is an important constraint on the coronal heating mechanisms. Observations indicate that the intensities and velocities measured in active region cores are effectively steady, suggesting that heating events occur rapidly enough to keep high-temperature active region loops close to equilibrium. In this …
A mid-infrared imaging catalogue of post-asymptotic giant branch stars
Gledhill, Tim; Matsuura, Mikako; Szczerba, Ryszard +11 more
Post-asymptotic giant branch (post-AGB) stars are key objects for the study of the dramatic morphological changes of low- to intermediate-mass stars on their evolution from the AGB towards the planetary nebula stage. There is growing evidence that binary interaction processes may very well have a determining role in the shaping process of many obj…