Search Publications
The Coincidence of Nuclear Star Clusters and Active Galactic Nuclei
Seth, Anil; Basu-Zych, Antara; Agüeros, Marcel +1 more
We study galaxies that host both nuclear star clusters and AGNs, implying the presence of a massive black hole. We select a sample of 176 galaxies with previously detected nuclear star clusters that range from ellipticals to late-type spirals. We search for AGNs in this sample using optical spectroscopy and archival radio and X-ray data. We find g…
Bars in Disk-dominated and Bulge-dominated Galaxies at z ~ 0: New Insights from ~3600 SDSS Galaxies
Jogee, Shardha; Barazza, Fabio D.; Marinova, Irina
We present a study of large-scale bars in the local universe, based on a large sample of 3692 galaxies, with 18.5 <= Mg < - 22.0 mag and redshift 0.01 <= z < 0.03, drawn from the Sloan Digitized Sky Survey. Our sample includes many galaxies that are disk-dominated and of late Hubble types. Both color cuts and Sérsic cuts yie…
Outflows at the Edges of Active Regions: Contribution to Solar Wind Formation?
Young, P. R.; Mandrini, C. H.; van Driel-Gesztelyi, L. +5 more
The formation of the slow solar wind has been debated for many years. In this Letter we show evidence of persistent outflow at the edges of an active region as measured by the EUV Imaging Spectrometer on board Hinode. The Doppler velocity ranged between 20 and 50 km s-1 and was consistent with a steady flow seen in the X-Ray Telescope. …
The Sloan Lens ACS Survey. VII. Elliptical Galaxy Scaling Laws from Direct Observational Mass Measurements
Treu, Tommaso; Schlegel, David J.; Gavazzi, Raphaël +5 more
We use a sample of 53 massive early-type strong gravitational lens galaxies with well-measured redshifts (ranging from z = 0.06 to 0.36) and stellar velocity dispersions (between 175 and 400 km s-1) from the Sloan Lens ACS (SLACS) Survey to derive numerous empirical scaling relations. The ratio between central stellar velocity dispersio…
Cosmic X-Ray Background and Earth Albedo Spectra with Swift BAT
Greiner, J.; Strong, A. W.; Ajello, M. +8 more
We use Swift BAT Earth occultation data at different geomagnetic latitudes to derive a sensitive measurement of the cosmic X-ray background (CXB) and of the Earth albedo emission in the 15-200 keV band. We compare our CXB spectrum with recent (INTEGRAL, BeppoSAX) and past results (HEAO-1) and find good agreement. Using an independent measurement o…
Optical and Near-Infrared Observations of the Highly Reddened, Rapidly Expanding Type Ia Supernova SN 2006X in M100
Filippenko, Alexei V.; Foley, Ryan J.; Li, Weidong +14 more
We present extensive optical (UBVRI), near-infrared (JK) light curves and optical spectroscopy of the Type Ia supernova SN 2006X in the nearby galaxy NGC 4321 (M100). Our observations suggest that either SN 2006X has an intrinsically peculiar color evolution or it is highly reddened [E(B - V)host = 1.42 +/- 0.04 mag ] with RV…
Acceleration in Fast Halo CMEs and Synchronized Flare HXR Bursts
Temmer, M.; Veronig, A. M.; Maričić, D. +4 more
We study two well-observed, fast halo CMEs, covering the full CME kinematics including the initiation and impulsive acceleration phase, and their associated flares. We find a close synchronization between the CME acceleration profile and the flare energy release as indicated by the RHESSI hard X-ray flux onsets, as well as peaks occur simultaneous…
The Very Low Albedo of an Extrasolar Planet: MOST Space-based Photometry of HD 209458
Moffat, Anthony F. J.; Rucinski, Slavek M.; Seager, Sara +8 more
Measuring the albedo of an extrasolar planet provides insight into its atmospheric composition and its global thermal properties, including heat dissipation and weather patterns. Such a measurement requires very precise photometry of a transiting system, fully sampling many phases of the secondary eclipse. Space-based optical photometry of the tra…
Stellar Proper Motions in the Galactic Bulge from Deep Hubble Space Telescope ACS WFC Photometry
Brown, Thomas M.; Casertano, Stefano; Smith, T. Ed +11 more
We present stellar proper motions in the Galactic bulge from the Sagittarius Window Eclipsing Extrasolar Search (SWEEPS) project using ACS WFC on HST. Proper motions are extracted for more than 180,000 objects, with >81,000 measured to accuracy better than 0.3 mas yr-1 in both coordinates. We report several results based on these mea…
The Magnetic Landscape of the Sun's Polar Region
Lites, B. W.; Ichimoto, K.; Tsuneta, S. +11 more
We present observations of the magnetic landscape of the polar region of the Sun that are unprecedented in terms of spatial resolution, field of view, and polarimetric precision. They were carried out with the Solar Optical Telescope aboard Hinode. Using a Milne-Eddington inversion, we find many vertically oriented magnetic flux tubes with field s…