Search Publications
The new emerging model for the structure of cooling cores in clusters of galaxies
Böhringer, H.; Churazov, E.; Chen, Y. +2 more
New X-ray observations with XMM-Newton show a lack of spectral evidence for large amounts of cooling and condensing gas in the centers of galaxy clusters believed to harbour strong cooling flows. This paper re-explores the cooling flow scenario in the light of the new observations. We explore the diagnostics of the temperature structure of cooling…
Time-Distance Helioseismology: The Forward Problem for Random Distributed Sources
Birch, A. C.; Gizon, L.
The forward problem of time-distance helioseismology is computing travel-time perturbations that result from perturbations to a solar model. We present a new and physically motivated general framework for calculations of the sensitivity of travel times to small local perturbations to solar properties, taking into account the fact that the sources …
Helioseismic Measurement of Solar Torsional Oscillations
Thompson, M. J.; Christensen-Dalsgaard, J.; Schou, J. +2 more
Bands of slower and faster rotation, the so-called torsional oscillations, are observed at the Sun's surface to migrate in latitude over the 11-year solar cycle. Here, we report on the temporal variations of the Sun's internal rotation from solar p-mode frequencies obtained over nearly 6 years by the Michelson Doppler Imager (MDI) instrument on bo…
The mass profile of A1413 observed with XMM-Newton: Implications for the M-T relation
Arnaud, M.; Pratt, G. W.
We present an XMM-Newton et al. observation of A1413, a hot (kT = 6.5 kev ) galaxy cluster at z=0.143. We construct gas and temperature profiles over the radial range up to ~ 1700 kpc. This radius corresponds to a density contrast delta ~ 500 with respect to the critical density at the redshift of the cluster, or equivalently ~ 0.7 r200…
Evidence of Spin and Energy Extraction in a Galactic Black Hole Candidate: The XMM-Newton/EPIC-pn Spectrum of XTE J1650-500
Wijnands, R.; Fabian, A. C.; Miller, J. M. +7 more
We observed the Galactic black hole candidate XTE J1650-500 early in its fall of 2001 outburst with the XMM-Newton European Photon Imaging pn Camera (EPIC-pn). The observed spectrum is consistent with the source having been in the ``very high'' state. We find a broad, skewed Fe Kα emission line that suggests the primary in this system may be a Ker…
Deviations from the Local Hubble Flow. I. The Tip of the Red Giant Branch as a Distance Indicator
Méndez, Bryan; Davis, Marc; Moustakas, John +3 more
The properties of the velocity field in the local volume (cz<550 km s-1) have been difficult to constrain because of a lack of a consistent set of galaxy distances. The sparse observations available to date suggest a remarkably quiet flow, with little deviation from a pure Hubble law. However, velocity field models based on the distr…
Detection of a Supernova Signature Associated with GRB 011121
Piro, L.; Axelrod, T. S.; Frontera, F. +20 more
Using observations from an extensive monitoring campaign with the Hubble Space Telescope, we present the detection of an intermediate-time flux excess that is redder in color relative to the afterglow of GRB 011121, currently distinguished as the gamma-ray burst with the lowest known redshift. The red ``bump,'' which exhibits a spectral rollover a…
Crystalline silicate dust around evolved stars. II. The crystalline silicate complexes
Waters, L. B. F. M.; Tielens, A. G. G. M.; Molster, F. J.
This is the second paper in a series of three in which we present an exhaustive inventory of the solid state emission bands observed in a sample of 17 oxygen-rich dust shells surrounding evolved stars. The data were taken with the Short and Long Wavelength Spectrographs on board of the Infrared Space Observatory (ISO) and cover the 2 to 200 mu m w…
A SAURON study of M32: measuring the intrinsic flattening and the central black hole mass
Copin, Y.; van der Marel, R. P.; de Zeeuw, P. T. +6 more
We present dynamical models of the nearby compact elliptical galaxy M32, using high-quality kinematic measurements, obtained with the integral-field spectrograph SAURON mounted on the William Herschel Telescope on La Palma. We also include STIS data obtained previously by Joseph et al. We find a best-fitting black hole mass of M•= (2.5 …
Successive CMEs and complex ejecta
St. Cyr, O. C.; Plunkett, S. P.; Burlaga, L. F.
We identified three sets of successive halo CMEs directed toward Earth (two or more CMEs observed within 1-4 days in the corona) and the corresponding flows and magnetic fields at 1 AU. Each set of successive halo CMEs was associated with complex ejecta at 1 AU. Complex ejecta were defined by [2001] as fast (>600 km/s) flows that are neither co…