Search Publications
The VOISE algorithm: a versatile tool for automatic segmentation of astronomical images
Achilleos, N.; Guio, P.
The auroras on Jupiter and Saturn can be studied with a high sensitivity and resolution by the Hubble Space Telescope (HST) ultraviolet (UV) and far-ultraviolet Space Telescope Imaging Spectrograph (STIS) and Advanced Camera for Surveys (ACS) instruments. We present results of automatic detection and segmentation of Jupiter's auroral emissions as …
Synchronization mechanism of sharp edges in rings of Saturn
Spahn, F.; Schmidt, J.; Shepelyansky, D. L. +1 more
We propose a new mechanism which explains the existence of enormously sharp edges in the rings of Saturn. This mechanism is based on the synchronization phenomenon due to which the epicycle rotational phases of particles in the ring, under certain conditions, become synchronized with the phase of external satellite, e.g. with the phase of Mimas in…
Kinetic properties of coronal mass ejections corrected for the projection effect in Cycle 23
Gao, Peng-Xin; Li, Ke-Jun; Li, Qi-Xiu
Using Howard et al.'s method, we investigate, before and after the projection correction, the speed and acceleration distributions for 1747 coronal mass ejections (CMEs) associated solely with flares (FL CMEs) and 631 CMEs associated solely with filament eruptions (FE CMEs) observed by the Large Angle and Spectrometric Coronagraph on board the Sol…
The role of E+A and post-starburst galaxies - II. Spectral energy distributions and comparison with observations
Kotulla, R.; Fritze, U.; Falkenberg, M. A.
In a previous paper, we have shown that the classical definition of E+A galaxies excludes a significant number of post-starburst galaxies. We suggested that analysing broad-band spectral energy distributions (SEDs) is a more comprehensive method to select and distinguish post-starburst galaxies than the classical definition of measuring equivalent…
The nature of the near-infrared core source in 3C 433
Sparks, W. B.; Tadhunter, C. N.; Axon, D. +4 more
We report the analysis of near-infrared (near-IR) imaging, polarimetric and spectroscopic observations of the powerful radio galaxy 3C 433 (z = 0.1016), obtained with the Hubble Space Telescope (HST) and the United Kingdom Infrared Telescope. The high spatial resolution of HST allows us to study the near-nuclear regions of the galaxy (<1 kpc). …
A measurement of the faint source correlation function in the GOODS and UDF surveys
Blandford, Roger; Morganson, Eric
We present a stable procedure for defining and measuring the two point angular autocorrelation function, w(θ) = [θ/θ0(V)]-Γ, of faint (25 < V < 29), barely resolved and unresolved sources in the Hubble Space Telescope Great Observatories Origins Deep Survey and Ultra Deep Field data sets. We construct catalogues that in…
Near-infrared imaging and spectroscopy of the nuclear region of the disturbed Virgo cluster spiral NGC4438
Casassus, Simon; Kenney, Jeffrey D. P.; Cortés, Juan R. +1 more
We present near-infrared (NIR) Very Large Telescope (VLT) Infrared Spectrometer and Array Camera (ISAAC) imaging and spectroscopy of the peculiar Virgo galaxy NGC4438, whose nucleus has been classified as a low-ionization nuclear emission-line region (LINER). The data are supplemented by mid-infrared imaging, and compared to previous HST broad-ban…
Detection of atmospheric haze on an extrasolar planet: the 0.55-1.05 µm transmission spectrum of HD 189733b with the HubbleSpaceTelescope
Moutou, C.; Pont, F.; Knutson, H. +2 more
The nearby transiting planet HD 189733b was observed during three transits with the Advanced Camera for Surveys of the Hubble Space Telescope in spectroscopic mode. The resulting time-series of 675 spectra covers the 550-1050 nm range, with a resolution element of ~8 nm, at extremely high accuracy (signal-to-noise ratio up to 10000 in 50-nm interv…
Galaxy merger morphologies and time-scales from simulations of equal-mass gas-rich disc mergers
Lotz, Jennifer M.; Primack, Joel R.; Jonsson, Patrik +1 more
A key obstacle to understanding the galaxy merger rate and its role in galaxy evolution is the difficulty in constraining the merger properties and time-scales from instantaneous snapshots of the real Universe. The most common way to identify galaxy mergers is by morphology, yet current theoretical calculations of the time-scales for galaxy distur…
Homogeneous studies of transiting extrasolar planets - I. Light-curve analyses
Southworth, John
I present a homogeneous analysis of the transit light curves of 14 well-observed transiting extrasolar planets. The light curves are modelled using JKTEBOP, random errors are measured using Monte Carlo simulations and the effects of correlated noise are included using a residual-permutation algorithm. The importance of stellar limb darkening on th…