Search Publications
Internal dynamics of Abell 2254: a merging galaxy cluster with a clumpy, diffuse radio emission
Gastaldello, F.; Nonino, M.; Bardelli, S. +3 more
Context. The mechanisms giving rise to diffuse radio emission in galaxy clusters and, in particular, their connection with cluster mergers are still being debated.
Aims: We explore the internal dynamics of Abell 2254, which has been shown to host a very clumpy and irregular radio halo.
Methods: Our analysis is mainly based on redshift da…
Dimming of the 17th Century Sun
Ortiz, Ada; Foukal, Peter; Schnerr, Roald
Reconstructions of total solar irradiance (TSI) rely mainly on linear relations between TSI variation and indices of facular area. When these are extrapolated to the prolonged 15th-17th century Spörer and Maunder solar activity minima, the estimated solar dimming is insufficient to explain the mid-millennial climate cooling of the Little Ice Age. …
A cold component and the complex velocity structure of DLA1331 + 170
Carswell, R. F.; Murphy, M. T.; Wolfe, A. M. +1 more
We examine the velocity structure in the gas associated with H I in the damped Lyα absorption system at redshift z= 1.7764 towards the QSO 1331 + 170 using Arecibo H I 21-cm data, optical spectra from the Keck High Resolution Echelle Spectrograph (HIRES) and European Southern Observatory (ESO) Very Large Telescope (VLT) Ultraviolet and Visual Eche…
Two-dimensional correlation functions for density and magnetic field fluctuations in magnetosheath turbulence measured by the Cluster spacecraft
Zong, Q. -G.; Tu, C. -Y.; Marsch, E. +3 more
Knowledge of multidimensional correlation functions is crucial for understanding the anisotropy of turbulence. The two-dimensional (2-D) spatial correlation functions (SCFs) obtained in previous studies of space plasma turbulence were restricted to large-length scales and covered a limited angular domain of the two-point separation vector with res…
Accretion states of the Galactic microquasar GRS 1758-258
Soria, Roberto; Pottschmidt, Katja; Mehdipour, Missagh +4 more
We present the results of a radio and X-ray study of the Galactic microquasar GRS 1758-258, using unpublished archival data and new observations. We focus in particular on the 2000-2002 state transitions, and on its more quiet behaviour in 2008-2009. Our spectral and timing analysis of the XMM-Newton data shows that the source was in the canonical…
Tracing the energetics and evolution of dust with Spitzer: a chapter in the history of the Eagle Nebula
Boulanger, F.; Paladini, R.; Noriega-Crespo, A. +5 more
Context. The Spitzer GLIMPSE and MIPSGAL surveys have revealed a wealth of details about the Galactic plane in the infrared (IR) with orders of magnitude higher sensitivity, higher resolution, and wider coverage than previous IR observations. The structure of the interstellar medium (ISM) is tightly connected to the countless star-forming regions.…
On the origin of fluctuations in the cusp diamagnetic cavity
Adamson, E.; Otto, A.; Nykyri, K. +1 more
We have analyzed Cluster magnetic field and plasma data during high-altitude cusp crossing on 14 February 2003. Cluster encountered a diamagnetic cavity (DMC) during northward interplanetary magnetic field (IMF) conditions, and as IMF rotated southward, the spacecraft reencountered the cavity more at the sunward side. The DMC is characterized by a…
The Optical Counterpart of NGC 1313 X-1
Feng, Hua; Kaaret, Philip; Yang, Lin
We identify the optical counterpart of the ultraluminous X-ray source (ULX) NGC 1313 X-1 and discuss constraints on its physical nature from multiband optical spectra. There is a single object on Hubble Space Telescope images within the aspect-corrected Chandra X-ray error circle; a fainter, possibly extended, feature lies near the edge of the err…
Anomalous radar backscatter from Titan’s surface?
Wye, L. C.; Janssen, M. A.; Le Gall, A.
Since Cassini arrived at Saturn in 2004, its moon Titan has been thoroughly mapped by the RADAR instrument at 2-cm wavelength, in both active and passive modes. Some regions on Titan, including Xanadu and various bright hummocky bright terrains, contain surfaces that are among the most radar-bright encountered in the Solar System. This high bright…
The location of an active nucleus and a shadow of a tidal tail in the ULIRG Mrk 273
Veilleux, S.; Sanders, D. B.; Surace, J. A. +9 more
Analysis of data from the Chandra X-ray Observatory for the double nucleus ULIRG Mrk 273 reveals an absorbed hard X-ray source coincident with the southwest nucleus, implying that this unresolved, near-infrared source is where an active nucleus resides, while the northern nuclear region contains a powerful starburst that dominates the far infrared…