Search Publications
Field-aligned currents associated with dipolarization fronts
Zong, Q. -G.; Parks, G. K.; Huang, S. Y. +7 more
Current densities associated with dipolarization fronts (DFs) have been calculated in the geomagnetic tail using the curlometer technique applied to high-resolution magnetic field B→ data obtained by the four Cluster spacecraft. We then use the relation <mfenced separators="" open="<" close=">">b→</mfenced>·<mfenced separators…
The Role of Galaxy Interaction in the SFR-M * Relation: Characterizing Morphological Properties of Herschel-selected Galaxies at 0.2 < z < 1.5
Le Floc'h, E.; Riguccini, L.; Sanders, D. B. +13 more
Galaxy interactions/mergers have been shown to dominate the population of IR-luminous galaxies (L IR >~ 1011.6 L ⊙) in the local universe (z <~ 0.25). Recent studies based on the relation between galaxies' star formation rates and stellar mass (the SFR-M * relation or the "galaxy main sequence") ha…
Evidence for a Cool Disk and Inhomogeneous Coronae from Wide-Band Temporal Spectroscopy of Cygnus X-1 with Suzaku
Done, Chris; Makishima, Kazuo; Yamada, Shin'ya +3 more
Unified X-ray spectral and timing studies of Cygnus X-1 in the low/hard and hard intermediate state were conducted in a model-independent manner, using broadband Suzaku data acquired on 25 occasions from 2005 to 2009 with a total exposure of ∼ 450 ks. The unabsorbed 0.1-500 keV source luminosity changed over 0.8%-2.8% of the Eddington limit for 14…
Optical Proper Motion Measurements of the M87 Jet: New Results from the Hubble Space Telescope
Anderson, Jay; van der Marel, Roeland P.; Sparks, W. B. +5 more
We report new results from a Hubble Space Telescope archival program to study proper motions in the optical jet of the nearby radio galaxy M87. Using over 13 yr of archival imaging, we reach accuracies below 0.1c in measuring the apparent velocities of individual knots in the jet. We confirm previous findings of speeds up to 4.5c in the inner 6'' …
The Atacama Cosmology Telescope: Physical Properties of Sunyaev-Zel'dovich Effect Clusters on the Celestial Equator
Hilton, Matt; Hasselfield, Matthew; Sifón, Cristóbal +29 more
We present the optical and X-ray properties of 68 galaxy clusters selected via the Sunyaev-Zel'dovich (SZ) effect at 148 GHz by the Atacama Cosmology Telescope (ACT). Our sample, from an area of 504 deg2 centered on the celestial equator, is divided into two regions. The main region uses 270 deg2 of the ACT survey that overla…
The Kelvin-Helmholtz Instability at Coronal Mass Ejection Boundaries in the Solar Corona: Observations and 2.5D MHD Simulations
Temmer, M.; Veronig, A. M.; Möstl, U. V.
The Atmospheric Imaging Assembly on board the Solar Dynamics Observatory observed a coronal mass ejection with an embedded filament on 2011 February 24, revealing quasi-periodic vortex-like structures at the northern side of the filament boundary with a wavelength of approximately 14.4 Mm and a propagation speed of about 310 ± 20 km s-1…
Physical Parameters of Standard and Blowout Jets
Romoli, Marco; Sterling, Alphonse C.; Pucci, Stefano +1 more
The X-ray Telescope on board the Hinode mission revealed the occurrence, in polar coronal holes, of much more numerous jets than previously indicated by the Yohkoh/Soft X-ray Telescope. These plasma ejections can be of two types, depending on whether they fit the standard reconnection scenario for coronal jets or if they include a blowout-like eru…
The Star Formation History of the Very Metal-poor Blue Compact Dwarf I Zw 18 from HST/ACS Data
Cignoni, M.; Tosi, M.; Clementini, G. +7 more
We have derived the star formation history (SFH) of the blue compact dwarf galaxy I Zw 18 through comparison of deep HST/ACS data with synthetic color-magnitude diagrams (CMDs). A statistical analysis was implemented for the identification of the best-fit SFH and relative uncertainties. We confirm that I Zw 18 is not a truly young galaxy, having s…
The magnetic field in the X-ray corona of Cygnus X-1
Malzac, J.; Bouchet, L.; De Cesare, G. +2 more
The different electron distributions in the hard and soft spectral states of black hole binaries could be caused by kinetic processes and changing because of varying physical conditions in the corona. In the presence of a magnetic field in the corona, the electron distribution can appear thermal, even when acceleration mechanisms would produce non…
A First Look at the Auriga-California Giant Molecular Cloud with Herschel and the CSO: Census of the Young Stellar Objects and the Dense Gas
Matthews, Brenda C.; Bourke, Tyler L.; Di Francesco, James +7 more
We have mapped the Auriga/California molecular cloud with the Herschel PACS and SPIRE cameras and the Bolocam 1.1 mm camera on the Caltech Submillimeter Observatory with the eventual goal of quantifying the star formation and cloud structure in this giant molecular cloud (GMC) that is comparable in size and mass to the Orion GMC, but which appears…