Search Publications
A Spitzer View of Protoplanetary Disks in the γ Velorum Cluster
Jeffries, R. D.; Gutermuth, R.; Stauffer, J. +4 more
We present new Spitzer Space Telescope observations of stars in the young (~5 Myr) γ Velorum stellar cluster. Combining optical and 2MASS photometry, we have selected 579 stars as candidate members of the cluster. With the addition of the Spitzer mid-infrared data, we have identified five debris disks around A-type stars and five to six debris dis…
Gemini and Hubble Space Telescope Evidence for an Intermediate-Mass Black Hole in ω Centauri
Gebhardt, Karl; Noyola, Eva; Bergmann, Marcel
The globular cluster ω Centauri is one of the largest and most massive members of the galactic system. However, its classification as a globular cluster has been challenged making it a candidate for being the stripped core of an accreted dwarf galaxy; this together with the fact that it has one of the largest velocity dispersions for star clusters…
Jets in Coronal Holes: Hinode Observations and Three-dimensional Computer Modeling
Galsgaard, K.; Moreno-Insertis, F.; Ugarte-Urra, I.
Recent observations of coronal hole areas with the XRT and EIS instruments on board the Hinode satellite have shown with unprecedented detail the launching of fast, hot jets away from the solar surface. In some cases these events coincide with episodes of flux emergence from beneath the photosphere. In this Letter we show results of a three-dimens…
Vigorous Star Formation with Low Efficiency in Massive Disk Galaxies at z = 1.5
Daddi, E.; Elbaz, D.; Morrison, G. +4 more
We present the first detection of molecular gas cooling CO emission lines from ordinary massive galaxies at z = 1.5. Two sources were observed with the IRAM Plateau de Bure Interferometer, selected to lie in the mass-star formation rate correlation at their redshift, thus being representative of massive high-z galaxies. Both sources were detected …
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…