Search Publications
Driving extreme variability: the evolving corona and evidence for jet launching in Markarian 335
Gallo, L. C.; Wilkins, D. R.
Variations in the X-ray emission from the narrow-line Seyfert 1 galaxy, Markarian 335, are studied on both long and short time-scales through observations made between 2006 and 2013 with XMM-Newton, Suzaku and NuSTAR. Changes in the geometry and energetics of the corona that give rise to this variability are inferred through measurements of the re…
Temperature as a third dimension in column-density mapping of dusty astrophysical structures associated with star formation
Marsh, K. A.; Whitworth, A. P.; Lomax, O.
We present point process mapping (<monospace>PPMAP</monospace>), a Bayesian procedure that uses images of dust continuum emission at multiple wavelengths to produce resolution-enhanced image cubes of differential column density as a function of dust temperature and position. <monospace>PPMAP</monospace> is based on the gene…
CSI 2264: Probing the inner disks of AA Tauri-like systems in NGC 2264
Aigrain, S.; Dougados, C.; Bouvier, J. +20 more
Context. The classical T Tauri star (CTTS) AA Tau has presented photometric variability that was attributed to an inner disk warp, caused by the interaction between the inner disk and an inclined magnetosphere. Previous studies of the young cluster NGC 2264 have shown that similar photometric behavior is common among CTTS.
Aims: The goal of t…
Interplanetary coronal mass ejections from MESSENGER orbital observations at Mercury
Lugaz, Noé; Farrugia, Charles J.; Schwadron, Nathan A. +4 more
We use observations from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, in orbit around Mercury, to investigate interplanetary coronal mass ejections (ICMEs) near 0.3 AU. MESSENGER is the first spacecraft since Helios 1 and 2 in the 1980s to make in situ measurements of the interplanetary medium at helioc…
Evidence for a Massive, Extended Circumgalactic Medium Around the Andromeda Galaxy
Wakker, Bart P.; Lehner, Nicolas; Howk, J. Christopher
We demonstrate the presence of an extended and massive circumgalactic medium (CGM) around Messier 31 using archival HST Cosmic Origins Spectrograph ultraviolet spectroscopy of 18 QSOs projected within two virial radii of M31 ({{R}vir}=300 kpc). We detect absorption from Si iii at -300≲ {{v}LSR}≲ -150 km s-1 toward …
Planck intermediate results. XXIV. Constraints on variations in fundamental constants
Kneissl, R.; Miville-Deschênes, M. -A.; Bernard, J. -P. +167 more
Any variation in the fundamental physical constants, more particularly in the fine structure constant, α, or in the mass of the electron, me, affects the recombination history of the Universe and cause an imprint on the cosmic microwave background angular power spectra. We show that the Planck data allow one to improve the constraint on…
Bayesian Ages for Early-type Stars from Isochrones Including Rotation, and a Possible Old Age for the Hyades
Huang, Chelsea X.; Brandt, Timothy D.
We combine recently computed models of stellar evolution using a new treatment of rotation with a Bayesian statistical framework to constrain the ages and other properties of early-type stars. We find good agreement for early-type stars and clusters with known young ages, including β Pictoris, the Pleiades, and the Ursa Majoris moving group. Howev…
Accounting for baryonic effects in cosmic shear tomography: determining a minimal set of nuisance parameters using PCA
Gnedin, Nickolay Y.; Eifler, Tim; Hearin, Andrew P. +3 more
Systematic uncertainties that have been subdominant in past large-scale structure (LSS) surveys are likely to exceed statistical uncertainties of current and future LSS data sets, potentially limiting the extraction of cosmological information. Here we present a general framework (Principal Component Analysis - PCA - marginalization) to consistent…
Planck's dusty GEMS: The brightest gravitationally lensed galaxies discovered with the Planck all-sky survey
Kneissl, R.; Altieri, B.; Le Floc'h, E. +30 more
We present an analysis of CO spectroscopy and infrared-to-millimetre dust photometry of 11 exceptionally bright far-infrared (FIR) and sub-mm sources discovered through a combination of the Planck all-sky survey and follow-up Herschel-SPIRE imaging - "Planck's Dusty Gravitationally Enhanced subMillimetre Sources". Each source has a secure spectros…
The Ages, Metallicities, and Element Abundance Ratios of Massive Quenched Galaxies at z ≈ 1.6
Daddi, E.; Carollo, C. M.; Gobat, R. +8 more
We investigate the stellar population properties of a sample of 24 massive quenched galaxies at 1.25< zspec< 2.09 identified in the COSMOS field with our Subaru/Multi-object Infrared Camera and Spectrograph near-IR spectroscopic observations. Tracing the stellar population properties as close to their major formation epoch as poss…