Search Publications
MARSIS remote sounding of localized density structures in the dayside Martian ionosphere: A study of controlling parameters
Gurnett, D. A.; Morgan, D. D.; Andrews, D. J. +2 more
Enhanced topside electron densities in the dayside Martian ionosphere have been repetitively observed in areas of near-radial crustal magnetic fields, for periods of tens of days, indicating their long-term spatial and temporal stability despite changing solar wind conditions. We perform a statistical study of these density structures using the io…
X-ray analysis of filaments in galaxy clusters
Fabian, A. C.; Sanders, J. S.; Walker, S. A. +1 more
We perform a detailed X-ray study of the filaments surrounding the brightest cluster galaxies in a sample of nearby galaxy clusters using deep Chandra observations, namely the Perseus, Centaurus and Virgo clusters, and Abell 1795. We compare the X-ray properties and spectra of the filaments in all of these systems, and find that their Chandra X-ra…
Comparison of Sunyaev-Zel'dovich measurements from Planck and from the Arcminute Microkelvin Imager for 99 galaxy clusters
Böhringer, H.; Kneissl, R.; Dahle, H. +39 more
We present observations and analysis of a sample of 123 galaxy clusters from the 2013 Planck catalogue of Sunyaev-Zel'dovich sources with the Arcminute Microkelvin Imager (AMI), a ground-based radio interferometer. AMI provides an independent measurement with higher angular resolution, 3 arcmin compared to the Planck beams of 5-10 arcmin. The AMI …
Searching for variable stars in the cores of five metal-rich globular clusters using EMCCD observations
Surdej, J.; Arellano Ferro, A.; Snodgrass, C. +32 more
Aims: In this paper, we present the analysis of time-series observations from 2013 and 2014 of five metal-rich ([Fe/H] > -1) globular clusters: NGC 6388, NGC 6441, NGC 6528, NGC 6638, and NGC 6652. The data have been used to perform a census of the variable stars in the central parts of these clusters.
Methods: The observations were m…
Confirmation of Hostless Type Ia Supernovae Using Hubble Space Telescope Imaging
Zaritsky, D.; Sand, D. J.; Graham, M. L. +1 more
We present deep Hubble Space Telescope imaging at the locations of four, potentially hostless, long-faded Type Ia supernovae (SNe Ia) in low-redshift, rich galaxy clusters that were identified in the Multi-Epoch Nearby Cluster Survey. Assuming a steep faint-end slope for the galaxy cluster luminosity function ({α }d=-1.5), our data incl…
New XMM-Newton observation of the Phoenix cluster: properties of the cool core
Altieri, B.; Valtchanov, I.; Menanteau, F. +9 more
Aims: We present a spectral analysis of a deep (220 ks) XMM-Newton observation of the Phoenix cluster (SPT-CL J2344-4243). We also use Chandra archival ACIS-I data that are useful for modeling the properties of the central bright active galactic nucleus and global intracluster medium.
Methods: We extracted CCD and reflection grating spec…
Deconstructing the narrow-line region of the nearest obscured quasar
Ramos Almeida, C.; Bellocchi, E.; Villar Martín, M. +3 more
We study the physical and kinematic properties of the narrow-line region (NLR) of the nearest obscured quasar MRK 477 (z = 0.037), using optical and near-infrared (NIR) spectroscopy. About 100 emission lines are identified in the optical+NIR spectrum (90 in the optical), including several narrow optical Fe+ lines. To our knowledge, this…
INTEGRAL 11-year hard X-ray survey above 100 keV
Sunyaev, R.; Krivonos, R.; Tsygankov, S. +3 more
We present the results of an all-sky survey, performed with data acquired by the Imager on-Board the INTEGRAL Satellite (IBIS) telescope on board the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) observatory over 11 years of operation, at energies above 100 keV. The catalogue of detected sources includes 132 objects. The statistical s…
Evolution of the Far-infrared Cloud at Titan’s South Pole
Teanby, N. A.; de Kok, R.; Flasar, F. M. +17 more
A condensate cloud on Titan identified by its 220 cm-1 far-infrared signature continues to undergo seasonal changes at both the north and south poles. In the north, the cloud, which extends from 55 N to the pole, has been gradually decreasing in emission intensity since the beginning of the Cassini mission with a half-life of 3.8 years.…
Effects of Rayleigh scattering on the CMB and cosmic structure
Sigurdson, Kris; Alipour, Elham; Hirata, Christopher M.
During and after recombination, in addition to Thomson scattering with free electrons, photons also couple to neutral hydrogen and helium atoms through Rayleigh scattering. This coupling influences both cosmic microwave background (CMB) anisotropies and the distribution of matter in the Universe. The frequency dependence of the Rayleigh cross sect…