Search Publications
Fermi and betatron acceleration of suprathermal electrons behind dipolarization fronts
André, M.; Vaivads, A.; Fu, H. S. +1 more
Two dipolarization front (DF) structures observed by Cluster in the Earth midtail region (XGSM ≈ -15 RE), showing respectively the feature of Fermi and betatron acceleration of suprathermal electrons, are studied in detail in this paper. Our results show that Fermi acceleration dominates inside a decaying flux pileup region (…
Herschel Detects a Massive Dust Reservoir in Supernova 1987A
van Loon, J. Th.; Lundqvist, P.; Okumura, K. +20 more
We report far-infrared and submillimeter observations of supernova 1987A, the star whose explosion was observed on 23 February 1987 in the Large Magellanic Cloud, a galaxy located 160,000 light years away. The observations reveal the presence of a population of cold dust grains radiating with a temperature of about 17 to 23 kelvin at a rate of abo…
The Discovery of Y Dwarfs using Data from the Wide-field Infrared Survey Explorer (WISE)
Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R. +13 more
We present the discovery of seven ultracool brown dwarfs identified with the Wide-field Infrared Survey Explorer (WISE). Near-infrared spectroscopy reveals deep absorption bands of H2O and CH4 that indicate all seven of the brown dwarfs have spectral types later than UGPS J072227.51-054031.2, the latest-type T dwarf currently…
An Extremely Luminous Panchromatic Outburst from the Nucleus of a Distant Galaxy
Cenko, S. B.; Sánchez-Ramírez, R.; Cooper, M. C. +60 more
Variable x-ray and γ-ray emission is characteristic of the most extreme physical processes in the universe. We present multiwavelength observations of a unique γ-ray-selected transient detected by the Swift satellite, accompanied by bright emission across the electromagnetic spectrum, and whose properties are unlike any previously observed source.…
Discovery of Powerful Gamma-Ray Flares from the Crab Nebula
Bignami, G. F.; Costa, E.; Mereghetti, S. +65 more
The well-known Crab Nebula is at the center of the SN1054 supernova remnant. It consists of a rotationally powered pulsar interacting with a surrounding nebula through a relativistic particle wind. The emissions originating from the pulsar and nebula have been considered to be essentially stable. Here, we report the detection of strong gamma-ray (…
Evolution of the dusty infrared luminosity function from z = 0 to z = 2.3 using observations from Spitzer
Magnelli, B.; Elbaz, D.; Frayer, D. T. +4 more
Aims: We derive the evolution of the infrared luminosity function (LF) over the last 4/5ths of cosmic time using deep 24 and 70 µm imaging of the GOODS North and South fields.
Methods: We use an extraction technique based on prior source positions at shorter wavelengths to build the 24 and 70 µm source catalogs. The majority …
A 100 pc Elliptical and Twisted Ring of Cold and Dense Molecular Clouds Revealed by Herschel Around the Galactic Center
Natoli, P.; Piacentini, F.; Polenta, G. +38 more
Thermal images of cold dust in the Central Molecular Zone of the Milky Way, obtained with the far-infrared cameras on board the Herschel satellite, reveal a ~3 × 107 M sun ring of dense and cold clouds orbiting the Galactic center. Using a simple toy model, an elliptical shape having semi-major axes of 100 and 60 pc is deduce…
VFISV: Very Fast Inversion of the Stokes Vector for the Helioseismic and Magnetic Imager
Schou, J.; Kubo, M.; Borrero, J. M. +4 more
In this paper we describe in detail the implementation and main properties of a new inversion code for the polarized radiative transfer equation (VFISV: Very Fast Inversion of the Stokes Vector). VFISV will routinely analyze pipeline data from the Helioseismic and Magnetic Imager (HMI) on-board of the Solar Dynamics Observatory (SDO). It will prov…
The VLT-FLAMES Tarantula Survey. I. Introduction and observational overview
van Loon, J. Th.; Costa, E.; Howarth, I. D. +39 more
The VLT-FLAMES Tarantula Survey (VFTS) is an ESO Large Programme that has obtained multi-epoch optical spectroscopy of over 800 massive stars in the 30 Doradus region of the Large Magellanic Cloud (LMC). Here we introduce our scientific motivations and give an overview of the survey targets, including optical and near-infrared photometry and compr…
Exclusion of a luminous red giant as a companion star to the progenitor of supernova SN 2011fe
Kulkarni, S. R.; Filippenko, Alexei V.; Cenko, S. Bradley +26 more
Type Ia supernovae are thought to result from a thermonuclear explosion of an accreting white dwarf in a binary system, but little is known of the precise nature of the companion star and the physical properties of the progenitor system. There are two classes of models: double-degenerate (involving two white dwarfs in a close binary system) and si…