Search Publications
The Einstein Ring 0047-2808 Revisited: A Bayesian Inversion
Brewer, B. J.; Lewis, G. F.
In a previous paper, we outlined a new Bayesian method for inferring the properties of extended gravitational lenses given data in the form of resolved images. This method holds the most promise for optimally extracting information from the observed image, while providing reliable uncertainties in all parameters. Here, we apply the method to the w…
Doppler Shift Correlations in the Solar Transition Region
Doschek, G. A.
I investigate dynamical correlations between the lower transition region and the upper transition region using spectra from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on the Solar and Heliospheric Observatory (SOHO) spacecraft. The measured quantity is the Doppler shift (mostly solar radial) along the line of sigh…
Suzaku Reveals Helium-burning Products in the X-Ray-emitting Planetary Nebula BD +30 3639
Hamaguchi, K.; Matsushita, K.; Hayashida, K. +7 more
BD +30 3639, the brightest planetary nebula at X-ray energies, was observed with Suzaku, an X-ray observatory launched on 2005 July 10. Using the X-ray Imaging Spectrometer, the K lines from C VI, O VII, and O VIII were resolved for the first time, and the C/O, N/O, and Ne/O abundance ratios were determined. The C/O and Ne/O abundance ratios excee…
A Flare of AE Aquarii Observed with XMM-Newton
Dotani, Tadayasu; Choi, Chul-Sung
We present the results of analyzing the XMM-Newton data obtained in 2001 November 7-8. A flare is observed simultaneously in X-ray and UV together with a quiescence. We find that during the flare event X-ray flux varies with UV with no significant time lag, indicating a close correlation of flux variation for X-ray and UV flares. An upper limit of…
Luminous Compact Blue Galaxies in Intermediate-Redshift Galaxy Clusters: A Significant but Extreme Butcher-Oemler Population
Bershady, M. A.; Hoessel, J. G.; Crawford, S. M. +1 more
We identify a population of luminous compact blue galaxies (LCBGs) in two galaxy clusters: MS 0451.6-0305 (z=0.54) and Cl 1604+4304 (z=0.9). LCBGs are identified via photometric characteristics and photometric redshifts derived from broad- and narrowband images taken with the WIYN telescope and the Hubble Space Telescope (HST). We analyze their su…
The Spitzer View of Low-Metallicity Star Formation. I. Haro 3
Hunt, Leslie K.; Sauvage, Marc; Thuan, Trinh X. +1 more
We present Spitzer observations of the blue compact dwarf galaxy Haro 3, with an oxygen abundance of 12+log(O/H)=8.32. These data are part of a larger study of star formation and dust in low-metallicity environments. The IRS spectrum of Haro 3 shows strong narrow PAH emission, with high equivalent widths. Gaseous nebular fine-structure lines are a…
Traveling Convective Modes in the Sun's Subsurface Shear Layer
Kosovichev, A. G.; Green, C. A.
Observations reveal that supergranular convective cells on the Sun rotate faster than the plasma on the solar surface. Recent time-distance helioseismology results from the Solar and Heliospheric Observatory Michelson Doppler Imager suggest that supergranulation has properties of traveling waves. We consider the idea that these properties are rela…
Keck Spectroscopy of Globular Clusters in the Virgo Cluster Dwarf Elliptical Galaxy VCC 1386
Conselice, Christopher J.
We present the results of a Keck spectroscopic study of globular clusters associated with the Virgo Cluster dwarf elliptical galaxy (dE) VCC 1386. We analyze blue spectroscopic absorption lines from 3500 to 5500 Å for 13 globular cluster candidates and confirm that five are associated with VCC 1386. By comparing metal and Balmer line indices of th…
Bright X-Ray Transients in M31: 2004 July XMM-Newton Observations
Trudolyubov, Sergey; Priedhorsky, William; Cordova, France
We present the results of X-ray observations of four bright transients sources detected in the 2004 July XMM-Newton observations of the central bulge of M31. Two X-ray sources, XMMU J004315.5+412440 and XMMU J004144.7+411110, were discovered for the first time. Two other sources, CXOM31 J004309.9+412332 and CXOM31 J004241.8+411635, were previously…
Resolving the Dusty Circumstellar Structure of the Enigmatic Symbiotic Star CH Cygni with the MMT Adaptive Optics System
Bieging, John H.; Marengo, Massimo; Hoffmann, William F. +6 more
We imaged the symbiotic star CH Cyg and two PSF calibration stars using the unique 6.5 m MMT deformable secondary adaptive optics system. Our high-resolution (FWHM = 0.3"), very high Strehl (98%+/-2%), mid-infrared (9.8 and 11.7 µm) images of CH Cyg allow us to probe finer length scales than ever before for this object. CH Cyg is significant…