Search Publications

Identification of Kinetic Alfvén Wave Turbulence in the Solar Wind
DOI: 10.1088/2041-8205/745/1/L9 Bibcode: 2012ApJ...745L...9S

Bale, S. D.; Chen, C. H. K.; Mozer, F. S. +4 more

The nature of small-scale turbulent fluctuations in the solar wind is investigated using a comparison of Cluster magnetic and electric field measurements to predictions arising from models consisting of either kinetic Alfvén waves or whistler waves. The electric and magnetic field properties of these waves from linear theory are used to construct …

2012 The Astrophysical Journal
Cluster 266
The intense starburst HDF 850.1 in a galaxy overdensity at z ≈ 5.2 in the Hubble Deep Field
DOI: 10.1038/nature11073 Bibcode: 2012Natur.486..233W

Carilli, Chris; Dickinson, Mark; Ellis, Richard +24 more

The Hubble Deep Field provides one of the deepest multiwavelength views of the distant Universe and has led to the detection of thousands of galaxies seen throughout cosmic time. An early map of the Hubble Deep Field at a wavelength of 850 micrometres, which is sensitive to dust emission powered by star formation, revealed the brightest source in …

2012 Nature
eHST 266
The mean star formation rate of X-ray selected active galaxies and its evolution from z ~ 2.5: results from PEP-Herschel
DOI: 10.1051/0004-6361/201219258 Bibcode: 2012A&A...545A..45R

Berta, S.; Magnelli, B.; Nordon, R. +37 more

We study relationships between star-formation rate (SFR) and the accretion luminosity and nuclear obscuration of X-ray selected active galactic nuclei (AGNs) using a combination of deep far-infrared (FIR) and X-ray data in three key extragalactic survey fields (GOODS-South, GOODS-North and COSMOS), as part of the PACS Evolutionary Probe (PEP) prog…

2012 Astronomy and Astrophysics
Herschel 266
Multiple Stellar Populations in 47 Tucanae
DOI: 10.1088/0004-637X/744/1/58 Bibcode: 2012ApJ...744...58M

Di Criscienzo, M.; Anderson, J.; Milone, A. P. +16 more

We use Hubble Space Telescope (HST) and ground-based imaging to study the multiple populations of 47 Tucanae (47 Tuc), combining high-precision photometry with calculations of synthetic spectra. Using filters covering a wide range of wavelengths, our HST photometry splits the main sequence into two branches, and we find that this duality is repeat…

2012 The Astrophysical Journal
eHST 264
A simplified view of blazars: clearing the fog around long-standing selection effects
DOI: 10.1111/j.1365-2966.2011.20044.x Bibcode: 2012MNRAS.420.2899G

D'Elia, V.; Polenta, G.; Giommi, P. +3 more

We propose a scenario where blazars are classified into flat-spectrum radio quasars (FSRQs), BL Lacertae (BL Lac) objects, low-synchrotron, or high-synchrotron peaked objects according to a varying mix of the Doppler-boosted radiation from the jet, the emission from the accretion disc, the broad-line region, and the light from the host galaxy. In …

2012 Monthly Notices of the Royal Astronomical Society
Planck 259
The chemical diversity of exo-terrestrial planetary debris around white dwarfs
DOI: 10.1111/j.1365-2966.2012.21201.x Bibcode: 2012MNRAS.424..333G

Gänsicke, B. T.; Breedt, E.; Koester, D. +3 more

We present Hubble Space Telescope (HST) ultraviolet spectroscopy of the white dwarfs PG 0843+516, PG 1015+161, SDSS 1228+1040, and GALEX 1931+0117, which accrete circumstellar planetary debris formed from the destruction of asteroids. Combined with optical data, a minimum of five and a maximum of 11 different metals are detected in their photosphe…

2012 Monthly Notices of the Royal Astronomical Society
eHST 256
A Herschel view of the far-infrared properties of submillimetre galaxies
DOI: 10.1051/0004-6361/201118312 Bibcode: 2012A&A...539A.155M

Smail, I.; Berta, S.; Magnelli, B. +48 more

We study a sample of 61submillimetre galaxies (SMGs) selected from ground-based surveys, with known spectroscopic redshifts and observed with the Herschel Space Observatory as part of the PACS Evolutionary Probe (PEP) and the Herschel Multi-tiered Extragalactic Survey (HerMES) guaranteed time key programmes. Our study makes use of the broad far-in…

2012 Astronomy and Astrophysics
Herschel 253
Updating quasar bolometric luminosity corrections
DOI: 10.1111/j.1365-2966.2012.20620.x Bibcode: 2012MNRAS.422..478R

Shang, Zhaohui; Brotherton, Michael S.; Runnoe, Jessie C.

Bolometric corrections are used in quasar studies to quantify total energy output based on a measurement of a monochromatic luminosity. First, we enumerate and discuss the practical difficulties of determining such corrections, then we present bolometric luminosities between 1 µm and 8 keV rest frame and corrections derived from the detailed…

2012 Monthly Notices of the Royal Astronomical Society
eHST 251
A Gaussian process framework for modelling instrumental systematics: application to transmission spectroscopy
DOI: 10.1111/j.1365-2966.2011.19915.x Bibcode: 2012MNRAS.419.2683G

Aigrain, S.; Pont, F.; Gibson, N. P. +3 more

Transmission spectroscopy, which consists of measuring the wavelength-dependent absorption of starlight by a planet's atmosphere during a transit, is a powerful probe of atmospheric composition. However, the expected signal is typically orders of magnitude smaller than instrumental systematics and the results are crucially dependent on the treatme…

2012 Monthly Notices of the Royal Astronomical Society
eHST 250
An absence of ex-companion stars in the type Ia supernova remnant SNR 0509-67.5
DOI: 10.1038/nature10692 Bibcode: 2012Natur.481..164S

Schaefer, Bradley E.; Pagnotta, Ashley

A type Ia supernova is thought to begin with the explosion of a white dwarf star. The explosion could be triggered by the merger of two white dwarfs (a `double-degenerate' origin), or by mass transfer from a companion star (the `single-degenerate' path). The identity of the progenitor is still controversial; for example, a recent argument against …

2012 Nature
eHST 245