Search Publications
Infrared Spectra and Photometry Of Complete Samples of Palomar-Green and Two Micron All Sky Survey Quasars
Balog, Z.; Rieke, G. H.; Shi, Yong +2 more
As a step toward a comprehensive overview of the infrared (IR) diagnostics of the central engines and host galaxies of quasars at low redshift, we present Spitzer Space Telescope spectroscopic (5-40 µm) and photometric (24, 70, and 160 µm) measurements of all Palomar-Green (PG) quasars at z < 0.5 and Two Micron All Sky Survey (2MASS…
Titan solar occultation observations reveal transit spectra of a hazy world
Fortney, Jonathan J.; Maltagliati, Luca; Marley, Mark S. +1 more
High altitude clouds and hazes are integral to understanding exoplanet observations, and are proposed to explain observed featureless transit spectra. However, it is difficult to make inferences from these data because of the need to disentangle effects of gas absorption from haze extinction. Here, we turn to the quintessential hazy world -- Titan…
Joint Planck and WMAP CMB map reconstruction
Starck, J. -L.; Sureau, F.; Bobin, J. +2 more
We present a novel estimate of the cosmological microwave background (CMB) map by combining the two latest full-sky microwave surveys: WMAP nine-year and Planck PR1. The joint processing benefits from a recently introduced component separation method coined"local-generalized morphological component analysis" (LGMCA) and based on the sparse distrib…
The surface geology and geomorphology of Phobos
Head, J. W.; Basilevsky, A. T.; Zubarev, A. E. +3 more
The martian moon Phobos is 26 km×22.8 km×18.2 km in size, and the major landforms on its surface are craters and grooves. We analyzed the visible craters on the surface of Phobos where ~1300 craters≥200 m in diameter, ~70 craters≥1 km, and ~30 craters≥2 km are identified; Stickney, the largest crater on Phobos, is about 8 km in diameter. Most crat…
The dayside ionospheres of Mars and Venus: Comparing a one-dimensional photochemical model with MaRS (Mars Express) and VeRa (Venus Express) observations
González-Galindo, F.; Tellmann, Silvia; Tyler, G. Leonard +8 more
The electron density distributions of the lower ionospheres of Mars and Venus are mainly dependent on the solar X-ray and EUV flux and the solar zenith angle. The influence of an increasing solar flux is clearly seen in the increase of the observed peak electron density and total electron content (TEC) of the main ionospheric layers. The model “Io…
High-resolution abundance analysis of red giants in the globular cluster NGC 6522
Minniti, D.; Chiappini, C.; Zoccali, M. +11 more
Context. The [Sr/Ba] and [Y/Ba] scatter observed in some galactic halo stars that are very metal-poor and in a few individual stars of the oldest known Milky Way globular cluster NGC 6522 have been interpreted as evidence of early enrichment by massive fast-rotating stars (spinstars). Because NGC 6522 is a bulge globular cluster, the suggestion wa…
The Intrinsic Two-dimensional Size of Sagittarius A*
Ghez, A. M.; Morris, M. R.; Bower, Geoffrey C. +9 more
We report the detection of the two-dimensional structure of the radio source associated with the Galactic Center black hole, Sagittarius A*, obtained from Very Long Baseline Array observations at a wavelength of 7 mm. The intrinsic source is modeled as an elliptical Gaussian with major-axis size 35.4 × 12.6 RS in position angle 95° east…
A Strongly Heated Neutron Star in the Transient Z Source MAXI J0556-332
Remillard, Ronald A.; Homan, Jeroen; Cackett, Edward M. +5 more
We present Chandra, XMM-Newton, and Swift observations of the quiescent neutron star in the transient low-mass X-ray binary MAXI J0556-332. Observations of the source made during outburst (with the Rossi X-ray Timing Explorer) reveal tracks in its X-ray color-color and hardness-intensity diagrams that closely resemble those of the neutron-star Z s…
Combined Multipoint Remote and in situ Observations of the Asymmetric Evolution of a Fast Solar Coronal Mass Ejection
Frahm, R. A.; Zhang, T. L.; Möstl, C. +8 more
We present an analysis of the fast coronal mass ejection (CME) of 2012 March 7, which was imaged by both STEREO spacecraft and observed in situ by MESSENGER, Venus Express, Wind, and Mars Express. Based on detected arrivals at four different positions in interplanetary space, it was possible to strongly constrain the kinematics and the shape of th…
More Kronoseismology with Saturn's rings
Nicholson, P. D.; Hedman, M. M.
In a previous paper, we developed tools which allowed us to confirm that several of the waves in Saturn's rings were likely generated by resonances with fundamental sectoral normal modes inside Saturn itself. Here we use these same tools to examine eight additional waves that are probably generated by structures inside the planet. One of these wav…