Search Publications
The ACS LCID Project. III. The Star Formation History of the Cetus dSph Galaxy: A Post-reionization Fossil
Dolphin, A. E.; Hidalgo, S. L.; Mayer, L. +12 more
We use deep HST/ACS observations to calculate the star formation history (SFH) of the Cetus dwarf spheroidal (dSph) galaxy. Our photometry reaches below the oldest main-sequence turnoffs, which allows us to estimate the age and duration of the main episode of star formation in Cetus. This is well approximated by a single episode that peaked roughl…
The Crab Nebula as a standard candle in very high-energy astrophysics
Horns, D.; Meyer, M.; Zechlin, H. -S.
The continuum high-energy gamma-ray emission between 1 GeV and 105 GeV from the Crab Nebula has been measured for the first time in overlapping energy bands by the Fermi large-area telescope (Fermi/LAT) below ≈100 GeV and by ground-based imaging air Cherenkov telescopes (IACTs) above ≈60 GeV. To follow up on the phenomenological approac…
Deviations from a uniform period spacing of gravity modes in a massive star
Aerts, Conny; Miglio, Andrea; Bloemen, Steven +13 more
The life of a star is dominantly determined by the physical processes in the stellar interior. Unfortunately, we still have a poor understanding of how the stellar gas mixes near the stellar core, preventing precise predictions of stellar evolution. The unknown nature of the mixing processes as well as the extent of the central mixed region is par…
Sizes, shapes, and derived properties of the saturnian satellites after the Cassini nominal mission
Thomas, P. C.
The Cassini spacecraft has provided data on over twenty satellites orbiting Saturn. In this study we update the shape measurements derived from imaging data of nearly all the observed regular satellites (those with low eccentricities and inclinations) and briefly discuss some of the implications of their properties. In particular, the improved dat…
Herschel/HIFI observations of interstellar OH+ and H2O+ towards W49N: a probe of diffuse clouds with a small molecular fraction
Menten, K. M.; Perault, M.; Boulanger, F. +50 more
We report the detection of absorption by interstellar hydroxyl cations and water cations, along the sight-line to the bright continuum source W49N. We have used Herschel's HIFI instrument, in dual beam switch mode, to observe the 972 GHz N = 1-0 transition of OH+ and the 1115 GHz 111-000 transition of ortho-H2…
Coexisting Flux Rope and Dipped Arcade Sections Along One Solar Filament
Aulanier, G.; Bommier, V.; Schmieder, B. +4 more
We compute the three-dimensional magnetic field of an active region in order to study the magnetic configuration of active region filaments. The nonlinear force-free field model is adopted to compute the magnetic field above the photosphere, where the vector magnetic field was observed by THEMIS/MTR on 2005 May 27. We propose a new method to remov…
Spectacular X-ray Tails, Intracluster Star Formation, and ULXs in A3627
Forman, W.; Sun, M.; Nulsen, P. E. J. +5 more
We present the discovery of spectacular double X-ray tails associated with ESO 137-001 and a possibly heated X-ray tail associated with ESO 137-002, both late-type galaxies in the closest rich cluster Abell 3627. A deep Chandra observation of ESO 137-001 allows us for the first time to examine the spatial and spectral properties of such X-ray tail…
HerMES: Far infrared properties of known AGN in the HerMES fields
Aussel, H.; Elbaz, D.; Pérez-Fournon, I. +72 more
Nuclear and starburst activity are known to often occur concomitantly. Herschel-SPIRE provides sampling of the far-infrared (FIR) spectral energy distributions (SEDs) of type 1 and type 2 AGN, allowing for the separation between the hot dust (torus) and cold dust (starburst) emission. We study large samples of spectroscopically confirmed type 1 an…
Black hole accretion discs in the canonical low-hard state
Fabian, A. C.; Miller, J. M.; Reis, R. C.
Stellar mass black holes in the low-hard state may hold clues to jet formation and basic accretion disc physics, but the nature of the accretion flow remains uncertain. A standard thin disc can extend close to the innermost stable circular orbit, but the inner disc may evaporate when the mass accretion rate is reduced. Blackbody-like continuum emi…
Pixel-based correction for Charge Transfer Inefficiency in the Hubble Space Telescope Advanced Camera for Surveys
Ellis, Richard; Leauthaud, Alexie; Massey, Richard +4 more
Charge Transfer Inefficiency (CTI) due to radiation damage above the Earth's atmosphere creates spurious trailing in Hubble Space Telescope (HST) images. Radiation damage also creates unrelated warm pixels - but these happen to be perfect for measuring CTI. We model CTI in the Advanced Camera for Surveys (ACS)/Wide Field Channel and construct a ph…