Search Publications
Multi-stranded and Multi-thermal Solar Coronal Loops: Evidence from Hinode X-ray Telescope and EUV Imaging Spectrometer Data
Golub, L.; Schmelz, J. T.; DeLuca, E. E. +4 more
Data from the X-Ray Telescope (XRT) and the EUV Imaging Spectrometer (EIS) on the Japanese/USA/UK Hinode spacecraft were used to investigate the spatial and thermal properties of an isolated quiescent coronal loop. We constructed differential emission measure (DEM) curves using Monte Carlo based, iterative forward fitting algorithms. We studied th…
Radarclinometry of the sand seas of Africa’s Namibia and Saturn’s moon Titan
Kirk, Randolph L.; Lorenz, Ralph D.; Neish, Catherine D. +1 more
Radarclinometry is a powerful technique for estimating heights of landforms in synthetic aperture radar (SAR) images of planetary surfaces. In particular, it has been used to estimate heights of dunes in the sand seas of Saturn's moon Titan (Lorenz, R.D., and 39 colleagues [2006]. Science 312, 724-727). In this work, we verify the technique by com…
The Bottom of the White Dwarf Cooling Sequence in the Old Open Cluster NGC 2158
Salaris, M.; Anderson, J.; Bedin, L. R. +3 more
We use 10 orbits of Advanced Camera for Surveys observations to reach the end of the white dwarf (WD) cooling sequence in the solar-metallicity open cluster NGC 2158. Our photometry and completeness tests show that the end falls at magnitude m F606W = 27.5 ± 0.15, which implies an age between ~1.8 and ~2.0 Gyr, consistent with the age o…
PKS 2005-489 at VHE: four years of monitoring with HESS and simultaneous multi-wavelength observations
Klochkov, D.; Santangelo, A.; Quirrenbach, A. +170 more
Aims: Our aim is to study the very high energy (VHE; E>100 GeV) γ-ray emission from BL Lac objects and the evolution in time of their broad-band spectral energy distribution (SED).
Methods: VHE observations of the high-frequency peaked BL Lac object PKS 2005-489 were made with the High Energy Stereoscopic System (HESS) from 2004 throu…
Melt and collapse of buried water ice: An alternative hypothesis for the formation of chaotic terrains on Mars
Zegers, Tanja E.; Oosthoek, Jelmer H. P.; Schumacher, Sandra +2 more
Chaotic terrains and the associated massive outflow channels are some of the most enigmatic features on Mars. Over hundreds of kilometres of rock units are fractured, tilted, and have subsided, forming chaotic terrain basins (Sharp, 1973). Large quantities of water emanated from these chaotic terrains in short periods of time in the Hesperian epoc…
Bright Points and Jets in Polar Coronal Holes Observed by the Extreme-Ultraviolet Imaging Spectrometer on Hinode
Landi, E.; Doschek, G. A.; Warren, H. P. +1 more
We present observations of polar coronal hole bright points (BPs) made with the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. The data consist of raster images of BPs in multiple spectral lines from mostly coronal ions, e.g., Fe X-Fe XV. The BPs are observed for short intervals and thus the data are snapshots of the BPs …
Gravitational lensing in the supernova legacy survey (SNLS)
Sullivan, M.; Astier, P.; Conley, A. +18 more
Aims: The observed brightness of type Ia supernovae is affected by gravitational lensing caused by the mass distribution along the line of sight, which introduces an additional dispersion into the Hubble diagram. We look for evidence of lensing in the SuperNova Legacy Survey 3-year data set.
Methods: We investigate the correlation betwee…
Large-scale distributions of mid- and far-infrared emission from the center to the halo of M 82 revealed with AKARI
Ohyama, Y.; Wada, T.; Onaka, T. +6 more
Context. The edge-on starburst galaxy M 82 exhibits complicated distributions of gaseous materials in its halo, which include ionized superwinds driven by nuclear starbursts, neutral materials entrained by the superwinds, and large-scale neutral streamers probably caused by a past tidal interaction with M 81.
Aims: We investigate detailed dis…
Evolution of blue E/S0 galaxies from z ~ 1: merger remnants or disk-rebuilding galaxies?
Bolzonella, M.; Koekemoer, A. M.; Huertas-Company, M. +3 more
Context. Studying outliers from the bimodal distribution of galaxies in the color-mass space, such as morphological early-type galaxies residing in the blue cloud (blue E/S0s), can help for better understanding the physical mechanisms that lead galaxy migrations in this space.
Aims: In this paper we try to bring new clues to studying the evol…
Scattered X-rays in Obscured Active Galactic Nuclei and Their Implications for Geometrical Structure and Evolution
Koss, Michael; Ueda, Yoshihiro; Awaki, Hisamitsu +4 more
We construct a new sample of 32 obscured active galactic nuclei (AGNs) selected from the Second XMM-Newton Serendipitous Source Catalogue to investigate their multiwavelength properties in relation to the "scattering fraction," the ratio of the soft X-ray flux to the absorption-corrected direct emission. The sample covers a broad range of the scat…