Search Publications
A decrease of the gas exchanges between galaxies and the intergalactic medium, from 12 to 6 billion years ago
Flores, H.; Hammer, F.; Puech, M. +2 more
Using a representative sample of 65 intermediate-mass galaxies at z∼ 0.6, we have investigated the interplay between the main ingredients of chemical evolution: metal abundance, gas mass, stellar mass and star formation rate (SFR). All quantities have been estimated using deep spectroscopy and photometry from ultraviolet to infrared and assuming a…
Herschel far-IR observations of the Chamaeleon molecular cloud complex . Chamaeleon I: A first view of young stellar objects in the cloud
Prusti, T.; Pilbratt, G. L.; André, Ph. +12 more
Context. The Herschel Gould Belt survey of nearby star forming regions is providing great insights into the early stages of the formation and the evolution of stars and their circumstellar disks. The Chamaeleon I dark cloud is an elongated region of dense dust and gas where star formation is ongoing in two centres, a northern region centred on Ced…
A Refined QSO Selection Method Using Diagnostics Tests: 663 QSO Candidates in the Large Magellanic Cloud
Trichas, Markos; Alcock, Charles; Rowan-Robinson, Michael +4 more
We present 663 QSO candidates in the Large Magellanic Cloud (LMC) selected using multiple diagnostics. We started with a set of 2566 QSO candidates selected using the methodology presented in our previous work based on time variability of the MACHO LMC light curves. We then obtained additional information for the candidates by crossmatching them w…
The Nature of the UV/Optical Emission of the Ultraluminous X-Ray Source in Holmberg II
Tao, Lian; Feng, Hua; Grisé, Fabien +1 more
We report on UV and X-ray spectroscopy and broadband optical observations of the ultraluminous X-ray source in Holmberg II. Fitting various stellar spectral models to the combined, non-simultaneous data set, we find that normal metallicity stellar spectra are ruled out by the data, while low-metallicity, Z = 0.1 Z ⊙, late O-star spectra…
The HST/ACS Coma Cluster Survey. VIII. Barred Disk Galaxies in the Core of the Coma Cluster
Ferguson, Henry C.; Mobasher, Bahram; Balcells, Marc +16 more
We use high-resolution (~0farcs1) F814W Advanced Camera for Surveys (ACS) images from the Hubble Space Telescope ACS Treasury survey of the Coma cluster at z ~ 0.02 to study bars in massive disk galaxies (S0s), as well as low-mass dwarf galaxies in the core of the Coma cluster, the densest environment in the nearby universe. Our study helps to con…
Microwave absorptivity by sulfuric acid in the Venus atmosphere: First results from the Venus Express Radio Science experiment VeRa
Pätzold, M.; Bird, M. K.; Häusler, B. +5 more
The Venus Express (VEX) Radio Science experiment VeRa utilizes radio occultation techniques to investigate the Venus atmosphere over a wide range of latitudes. Radio attenuation measurements with the VEX 3.6 cm (X-band) signal provide information on the absorptivity distribution within the Venus cloud deck. The combined results from 6 years of occ…
Nonlinear interaction between ring current protons and electromagnetic ion cyclotron waves
Zhu, Hui; Su, Zhenpeng; Xiao, Fuliang +4 more
Electromagnetic ion cyclotron (EMIC) waves have long been suggested to account for the rapid decay of ring current, which is usually described by the quasi-linear theory. We demonstrate that the interactions between ring current protons and typical EMIC waves can be highly nonlinear. A dimensionless parameterRis derived to identify the nonlinear i…
Discovery of Crystallized Water Ice in a Silhouette Disk in the M43 Region
Tokunaga, Alan T.; Terada, Hiroshi
We present the 1.9-4.2 µm spectra of the five bright (L <= 11.2) young stars associated with silhouette disks with a moderate to high inclination angle of 39°-80° in the M42 and M43 regions. The water ice absorption is seen toward d121-1925 and d216-0939, while the spectra of d182-316, d183-405, and d218-354 show no water ice feature arou…
High frame rate imaging based photometry. Photometric reduction of data from electron-multiplying charge coupled devices (EMCCDs)
Grundahl, F.; Jørgensen, U. G.; Harpsøe, K. B. W. +1 more
Context. The EMCCD is a type of CCD that delivers fast readout times and negligible readout noise, making it an ideal detector for high frame rate applications which improve resolution, like lucky imaging or shift-and-add. This improvement in resolution can potentially improve the photometry of faint stars in extremely crowded fields significantly…
Titan's Transport-driven Methane Cycle
Mitchell, Jonathan L.
The mechanisms behind the occurrence of large cloud outbursts and precipitation on Titan have been disputed. A global- and annual-mean estimate of surface fluxes indicated only 1% of the insolation, or ~0.04 W m-2, is exchanged as sensible and/or latent fluxes. Since these fluxes are responsible for driving atmospheric convection, it ha…