Search Publications
The chemical diversity of exo-terrestrial planetary debris around white dwarfs
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…
A Herschel view of the far-infrared properties of submillimetre galaxies
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…
Updating quasar bolometric luminosity corrections
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…
A Gaussian process framework for modelling instrumental systematics: application to transmission spectroscopy
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…
An absence of ex-companion stars in the type Ia supernova remnant SNR 0509-67.5
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 …
Comparison of Line-of-Sight Magnetograms Taken by the Solar Dynamics Observatory/Helioseismic and Magnetic Imager and Solar and Heliospheric Observatory/Michelson Doppler Imager
Liu, Y.; Sun, X.; Hoeksema, J. T. +7 more
We compare line-of-sight magnetograms from the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) and the Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric Observatory (SOHO). The line-of-sight magnetic signal inferred from the calibrated MDI data is greater than that derived from the HMI data by a …
Global model of lower band and upper band chorus from multiple satellite observations
Meredith, Nigel P.; Horne, Richard B.; Thorne, Richard M. +4 more
Gyroresonant wave particle interactions with whistler mode chorus play a fundamental role in the dynamics of the Earth's radiation belts and inner magnetosphere, affecting both the acceleration and loss of radiation belt electrons. Knowledge of the variability of chorus wave power as a function of both spatial location and geomagnetic activity, re…
GOODS-Herschel: the far-infrared view of star formation in active galactic nucleus host galaxies since z ≈ 3
Magnelli, B.; Lutz, D.; Altieri, B. +28 more
We present a study of the infrared properties of X-ray selected, moderate-luminosity (i.e. LX= 1042-1044 erg s-1) active galactic nuclei (AGNs) up to z ≈ 3, in order to explore the links between star formation in galaxies and accretion on to their central black holes. We use 100 and 160 µ m fluxes …
Fundamental parameters and infrared excesses of Hipparcos stars
Zijlstra, A. A.; Boyer, M. L.; McDonald, I.
We derive the fundamental parameters (temperature and luminosity) of 107 619 Hipparcos stars and place these stars on a true Hertzsprung-Russell diagram. This is achieved by comparing BT-SETTL model atmospheres to spectral energy distributions (SEDs) created from Hipparcos, Tycho, Sloan Digital Sky Survey, DENIS, Two Micron All Sky Survey, MSX, AK…
Rotational velocities of A-type stars. IV. Evolution of rotational velocities
Royer, F.; Zorec, J.
Context. In previous works of this series, we have shown that late B- and early A-type stars have genuine bimodal distributions of rotational velocities and that late A-type stars lack slow rotators. The distributions of the surface angular velocity ratio Ω/Ωcrit (Ωcrit is the critical angular velocity) have peculiar shapes a…