Search Publications
Constraints on Dark Energy from Supernovae, Gamma-Ray Bursts, Acoustic Oscillations, Nucleosynthesis, Large-Scale Structure, and the Hubble Constant
Wright, E. L.
The luminosity distance versus redshift law is now measured using supernovae and γ-ray bursts, and the angular size distance is measured at the surface of last scattering by the CMB and at z=0.35 by baryon acoustic oscillations. In this paper, this data is fit to models for the equation of state with w=-1, w=constant, and w(z)=w0+w…
Identification of Absorption Features in an Extrasolar Planet Atmosphere
Barman, T.
Water absorption is identified in the atmosphere of HD 209458b by comparing models for the planet's transmitted spectrum to recent, multiwavelength, eclipse-depth measurements (from 0.3 to 1 µm) published by Knutson et al. A cloud-free model that includes solar abundances, rainout of condensates, and photoionization of sodium and potassium i…
Physical Properties, Baryon Content, and Evolution of the Lyα Forest: New Insights from High-Resolution Observations at z <~ 0.4
Savage, B. D.; Wakker, B. P.; Sembach, K. R. +3 more
We present a study of the Lyα forest at z<~0.4, from which we conclude that at least 20% of the total baryons in the universe are located in the highly ionized gas traced by broad Lyα absorbers. The cool photoionized low-z intergalactic medium (IGM) probed by narrow Lyα absorbers contains about 30% of the baryons. We further find that the ratio…
On the Iwasawa-Taniguchi effect of radio-quiet AGN
Bianchi, S.; Guainazzi, M.; Matt, G. +1 more
Aims:The existence of an anti-correlation between the Equivalent Width (EW) of the neutral narrow core of the iron Kα emission line and the 2-10 keV luminosity (the so-called "X-ray Baldwin" or "Iwasawa-Taniguchi" effect) has been debated in the last years. We aim at testing this claim on the largest catalogue of radio quiet AGN high-quality X-ray…
The Effects of Environment on Morphological Evolution at 0<z<1.2 in the COSMOS Survey
Mobasher, Bahram; Ellis, Richard S.; Capak, Peter +4 more
We explore the evolution of the morphology-density relation using the COSMOS Advanced Camera for Surveys (ACS) and previous cluster studies. The Gini parameter measured in a Petrosian aperture is found to be an effective way of selecting early-type galaxies free from systematic effects with redshift. We find that galaxies are transformed from late…
Structural Parameters for Globular Clusters in M31 and Generalizations for the Fundamental Plane
Forbes, Duncan A.; Barmby, Pauline; Harris, William E. +2 more
The structures of globular clusters (GCs) reflect their dynamical states and past histories. High-resolution imaging allows the exploration of morphologies of clusters in other galaxies. Surface brightness profiles from new Hubble Space Telescope observations of 34 GCs in M31 are presented, together with fits of several different structural models…
Asteroseismology and interferometry
Quirrenbach, A.; Eggenberger, P.; Thompson, M. J. +22 more
Asteroseismology provides us with a unique opportunity to improve our understanding of stellar structure and evolution. Recent developments, including the first systematic studies of solar-like pulsators, have boosted the impact of this field of research within astrophysics and have led to a significant increase in the size of the research communi…
Structure of the Venus atmosphere
Khatuntsev, I.; Zasova, L. V.; Ignatiev, N. +1 more
The structure of the Venus atmosphere is discussed. The data obtained in the 1980s by the last Soviet missions to Venus: orbiters Venera 15, 16 and the entry probes and balloons of Vega 1 and 2 are compared with the Venus International Reference Atmosphere (VIRA) model. VIRA is based on the data of the extensive space investigations of Venus in th…
Further Indications of Jet Rotation in New Ultraviolet and Optical Hubble Space Telescope STIS Spectra
Bacciotti, Francesca; Coffey, Deirdre; Eislöffel, Jochen +2 more
We present survey results that suggest rotation signatures at the base of T Tauri jets. Observations were conducted with the Hubble Space Telescope Imaging Spectrograph at optical and near-ultraviolet (NUV) wavelengths. Results are presented for the approaching jet from DG Tau, CW Tau, HH 30, and the bipolar jet from TH 28. Systematic asymmetries …
RPC-LAP: The Rosetta Langmuir Probe Instrument
Wahlund, J. -E.; André, M.; Jansson, S. -E. +10 more
The Rosetta dual Langmuir probe instrument, LAP, utilizes the multiple powers of a pair of spherical Langmuir probes for measurements of basic plasma parameters with the aim of providing detailed knowledge of the outgassing, ionization, and subsequent plasma processes around the Rosetta target comet. The fundamental plasma properties to be studied…