Search Publications
Simultaneous Estimation of Time Delays and Quasar Structure
Kochanek, C. S.; Morgan, Nicholas D.; Meylan, G. +5 more
We expand our Bayesian Monte Carlo method for analyzing the light curves of gravitationally lensed quasars to simultaneously estimate time delays and the sizes of quasar continuum emission regions including their mutual uncertainties. We apply the method to HE1104-1805 and QJ0158-4325, two doubly imaged quasars with microlensing and intrinsic vari…
Titan airglow spectra from the Cassini Ultraviolet Imaging Spectrograph: FUV disk analysis
Stewart, Ian; Gustin, Jacques; Ajello, Joseph M. +7 more
We present a spectral analysis of the far ultraviolet (FUV: 1150-1900 Å) disk airglow observations of Titan's atmosphere by the Cassini Ultraviolet Imaging Spectrograph (UVIS). The FUV spectrum consists of emissions from the Lyman-Birge-Hopfield (LBH) band system of N2 excited by photoelectrons (a 1Πg → X 1Σg +), N I multiplets from solar photodis…
On the White Dwarf Cooling Sequence of the Globular Cluster ω Centauri
Degl'Innocenti, S.; Marchetti, E.; Pulone, L. +16 more
We present deep and precise photometry (F435W, F625W, F658N) of ω Cen collected with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope (HST). We have identified ≈6500 white dwarf (WD) candidates, and the ratio of WD to main-sequence (MS) star counts is found to be at least a factor of 2 larger than the ratio of CO-core WD c…
Galaxy populations in the Antlia cluster - II. Compact elliptical galaxy candidates
Richtler, Tom; Faifer, Favio R.; Smith Castelli, Analía V. +1 more
Continuing our study of galaxy populations in the Antlia cluster, we present a photometric analysis of four galaxies classified as compact elliptical (cE) galaxies in the 1990 Antlia Group catalogue of Ferguson and Sandage. Until now, there have been only six known members of this rare type of galaxy. Using data from various photometric systems (W…
Relationship between solar wind corotating interaction regions and the phasing and intensity of Saturn kilometric radiation bursts
Cecconi, B.; Lamy, L.; Badman, S. V. +2 more
Voyager spacecraft measurements of Saturn kilometric radiation (SKR) identified two features of these radio emissions: that they pulse at a period close to the planetary rotation period, and that the emitted intensity is correlated with the solar wind dynamic pressure (Desch and Kaiser, 1981; Desch, 1982; Desch and Rucker, 1983). In this study the…
Determination of Magnetic Diffusivity from High-Resolution Solar Magnetograms
Chae, Jongchul; Litvinenko, Yuri E.; Sakurai, Takashi
The magnetic diffusivity in the solar photosphere is determined by applying a new method to the magnetic induction equation. The magnetic field evolution is specified by a time sequence of high-resolution magnetograms of plage regions, taken by Hinode/SOT and SOHO/MDI. The mean value of magnetic diffusivity determined from SOT magnetograms with th…
Probing the Subsurface Structures of Active Regions with Ring-Diagram Analysis
Basu, Sarbani; Antia, H. M.; Bogart, Richard S. +1 more
We analyze the variations in the near-surface profiles of sound speed and adiabatic constant between active regions and neighboring quiet-Sun areas using the technique of ring-diagram analysis and inversions of the frequency differences between the regions. This approach minimizes the systematic observational effects on the fitted spectral model p…
The environmental dependence of properties of galaxies around the RDCSJ0910+54 cluster at z = 1.1
Finoguenov, A.; Morokuma, T.; Tanaka, M. +6 more
We report on the environmental dependence of properties of galaxies around the RDCSJ0910+54 cluster at z=1.1. We obtained multi-band wide-field images of the cluster with Suprime-Cam and MOIRCS on Subaru and WFCAM on UKIRT. Also, an intensive spectroscopic campaign was carried out using LRIS on Keck and FOCAS on Subaru. We collected 161 spectra wi…
The Optical Spectra of 24 µm Galaxies in the COSMOS Field. I. Spitzer MIPS Bright Sources in the zCOSMOS-Bright 10k Catalog
Kneib, J. -P.; Maccagni, D.; Aussel, H. +62 more
We study zCOSMOS-bright optical spectra for 609 Spitzer MIPS 24 µm-selected galaxies with S24 µ m > 0.30 mJy and I < 22.5 (AB mag) over 1.5 deg2 of the COSMOS field. From emission-line diagnostics we find the following: (1) SFRs derived from the observed Hα λ6563 and Hβ λ4861 lines underestimate, on average,…
Venus upper atmosphere winds from ground-based heterodyne spectroscopy of CO 2 at 10µm wavelength
Sornig, M.; Livengood, T.; Sonnabend, G. +4 more
We report observations of Venus atmospheric wind near 110 km altitude by means of high-resolution mid-infrared spectroscopy. Data were acquired May 28-June 4, 2007 at the McMath-Pierce Solar Telescope (Kitt Peak, Arizona, USA), during a coordinated ground-based observing campaign in support of Venus Express. The Cologne Tuneable Heterodyne Infrare…