Search Publications
Optimal estimation retrievals of the atmospheric structure and composition of HD 189733b from secondary eclipse spectroscopy
Fletcher, L. N.; Lee, J. -M.; Irwin, P. G. J.
Recent spectroscopic observations of transiting hot Jupiters have permitted the derivation of the thermal structure and molecular abundances of H2O, CO2, CO and CH4 in these extreme atmospheres. Here, for the first time, we apply the technique of optimal estimation to determine the thermal structure and composition…
Bipolar Magnetic Regions on the Sun: Global Analysis of the SOHO/MDI Data Set
Kosovichev, A. G.; Stenflo, J. O.
The magnetic flux that is generated by dynamo processes inside the Sun emerges in the form of bipolar magnetic regions. The properties of these directly observable signatures of the dynamo can be extracted from full-disk solar magnetograms. The most homogeneous, high-quality synoptic data set of solar magnetograms has been obtained with the Michel…
First Detection of Water Vapor in a Pre-stellar Core
Caselli, Paola; Codella, Claudio; Aikawa, Yuri +11 more
Water is a crucial molecule in molecular astrophysics as it controls much of the gas/grain chemistry, including the formation and evolution of more complex organic molecules in ices. Pre-stellar cores provide the original reservoir of material from which future planetary systems are built, but few observational constraints exist on the formation o…
The morphologies of massive galaxies at 1 < z < 3 in the CANDELS-UDS field: compact bulges, and the rise and fall of massive discs
Ferguson, H. C.; McLure, R. J.; Dunlop, J. S. +16 more
We have used high-resolution, Hubble Space Telescope, near-infrared imaging to conduct a detailed analysis of the morphological properties of the most massive galaxies at high redshift, modelling the WFC3/IR H160-band images of the ≃200 galaxies in the CANDELS-UDS field with photometric redshifts 1 < z < 3, and stellar masses M
No Clear Submillimeter Signature of Suppressed Star Formation among X-Ray Luminous Active Galactic Nuclei
Magnelli, B.; Altieri, B.; Daddi, E. +18 more
Many theoretical models require powerful active galactic nuclei (AGNs) to suppress star formation in distant galaxies and reproduce the observed properties of today's massive galaxies. A recent study based on Herschel-SPIRE submillimeter observations claimed to provide direct support for this picture, reporting a significant decrease in the mean s…
Stellar clusters in M83: formation, evolution, disruption and the influence of the environment
Bastian, N.; Larsen, S. S.; Smith, L. J. +6 more
We study the stellar cluster population in two adjacent fields in the nearby, face-on spiral galaxy M83 using multiwavelength Wide Field Camera 3/Hubble Space Telescope imaging. After automatic detection procedures, the clusters are selected through visual inspection to be centrally concentrated, symmetric, and resolved on the images, which allows…
Occurrence rate of earthward-propagating dipolarization fronts
André, M.; Vaivads, A.; Huang, S. Y. +2 more
The occurrence rate of earthward-propagating dipolarization fronts (DFs) is investigated in this paper based on the 9 years (2001-2009) of Cluster 1 data. For the first time, we select the DF events by fitting the characteristic increase in Bz using a hyperbolic tangent function. 303 earthward-propagating DFs are found; they have on ave…
Faint high-redshift AGN in the Chandra deep field south: the evolution of the AGN luminosity function and black hole demography
Pannella, M.; Fiore, F.; Castellano, M. +14 more
Context. We present detection and analysis of faint X-ray sources in the Chandra deep field south (CDFS) using the 4 Ms Chandra observation.
Aims: We place constraints on active galactic nuclei (AGN) luminosity functions at z = 3-7, its cosmological evolution, and high-redshift black hole and AGN demography.
Methods: We use a new detecti…
Investigations of dust heating in M81, M83 and NGC 2403 with the Herschel Space Observatory
Clements, D. L.; Roussel, H.; Cooray, A. +21 more
We use Spitzer Space Telescope and Herschel Space Observatory far-infrared data along with ground-based optical and near-infrared data to understand how dust heating in the nearby face-on spiral galaxies M81, M83 and NGC 2403 is affected by the starlight from all stars and by the radiation from star-forming regions. We find that 70/160 ?m surface …
Quantifying Spicules
De Pontieu, Bart; Carlsson, Mats; Pereira, Tiago M. D.
Understanding the dynamic solar chromosphere is fundamental in solar physics. Spicules are an important feature of the chromosphere, connecting the photosphere to the corona, potentially mediating the transfer of energy and mass. The aim of this work is to study the properties of spicules over different regions of the Sun. Our goal is to investiga…