Search Publications
A Spectroscopic Survey of Redshift 1.4<~z<~3.0 Galaxies in the GOODS-North Field: Survey Description, Catalogs, and Properties
Pettini, Max; Erb, Dawn K.; Shapley, Alice E. +2 more
We present the results of a spectroscopic survey with LRIS-B on Keck of more than 280 star-forming galaxies and AGNs at redshifts 1.4<~z<~3.0 in the GOODS-N field. Candidates are selected by their UnGR colors using the ``BM/BX'' criteria to target redshift 1.4<~z<~2.5 galaxies and the LBG criteria to target redshift z~3 gala…
Constraints on the Physics of Type Ia Supernovae from the X-Ray Spectrum of the Tycho Supernova Remnant
Hughes, John P.; Hwang, Una; Badenes, Carles +2 more
In this paper we use high-quality X-ray observations from XMM-Newton and Chandra to gain new insights into the explosion that originated Tycho's supernova 433 yr ago. We perform a detailed comparison between the ejecta emission from the spatially integrated X-ray spectrum of the supernova remnant and current models for Type Ia supernova explosions…
A Model for Spectral and Compositional Variability at High Energies in Large, Gradual Solar Particle Events
Lee, Martin A.; Tylka, Allan J.
Shocks driven by fast coronal mass ejections (CMEs) are generally believed to be the dominant accelerators in large, gradual solar energetic particle (SEP) events. A key challenge for this notion has been the highly variable spectral and compositional characteristics of these events above a few tens of MeV per nucleon. We have recently proposed th…
The SAURON project - VII. Integral-field absorption and emission-line kinematics of 24 spiral galaxy bulges
Bacon, Roland; Krajnović, Davor; Emsellem, Eric +10 more
We present observations of the stellar and gas kinematics for a representative sample of 24 Sa galaxies obtained with our custom-built integral-field spectrograph SAURON operating on the William Herschel Telescope. The data have been homogeneously reduced and analysed by means of a dedicated pipeline. All resulting data cubes were spatially binned…
The Gravity Field of the Saturnian System from Satellite Observations and Spacecraft Tracking Data
Jacobson, R. A.; Owen, W. M., Jr.; Mackenzie, R. A. +11 more
We present values for the masses of Saturn and its major satellites, the zonal harmonics in the spherical harmonic expansion of Saturn's gravitational potential, and the orientation of the pole of Saturn. We determined these values using an extensive data set: satellite astrometry from Earth-based observatories and the Hubble Space Telescope; Eart…
Keplerian discs around post-AGB stars: a common phenomenon?
Waters, L. B. F. M.; Dejonghe, H.; de Ruyter, S. +3 more
Aims.We aim at showing that the broad-band SED characteristics of our sample of post-AGB stars are best interpreted, assuming the circumstellar dust is stored in Keplerian rotating passive discs.Methods.We present a homogeneous and systematic study of the Spectral Energy Distributions (SEDs) of a sample of 51 post-AGB objects. The selection criter…
Evolutionary state of magnetic chemically peculiar stars
Kochukhov, O.; Bagnulo, S.
Context: .The photospheres of about 5-10% of the upper main sequence stars exhibit remarkable chemical anomalies. Many of these chemically peculiar (CP) stars have a global magnetic field, the origin of which is still a matter of debate.
Aims: .We present a comprehensive statistical investigation of the evolution of magnetic CP stars, aimed at…
Adaptive binning of X-ray data with weighted Voronoi tessellations
Statler, Thomas S.; Diehl, Steven
We present a technique to adaptively bin sparse data using weighted Voronoi tessellations (WVTs). WVT binning is a generalization of the Voronoi binning algorithm by Cappellari & Copin, developed for integral field spectroscopy. WVT binning is applicable to many types of data and creates unbiased binning structures with compact bins that do no…
Spectral analysis of the Galactic e+e- annihilation emission
Knödlseder, J.; Marcowith, A.; Guessoum, N. +5 more
We present a spectral analysis of the e+e- annihilation emission from the Galactic Centre region based on the first year of measurements made with the spectrometer SPI of the INTEGRAL mission. We have found that the annihilation spectrum can be modelled by the sum of a narrow and a broad 511 keV line plus an ortho-positronium…
Effective temperature scale and bolometric corrections from 2MASS photometry
Ribas, I.; Jordi, C.; Masana, E.
We present a method to determine effective temperatures, angular semi-diameters and bolometric corrections for population I and II FGK type stars based on V and 2MASS IR photometry. Accurate calibration is accomplished by using a sample of solar analogues, whose average temperature is assumed to be equal to the solar effective temperature of 5777 …