Search Publications
Imaging the Cool Hypergiant NML Cygni's Dusty Circumstellar Envelope with Adaptive Optics
Humphreys, R. M.; Schuster, M. T.; Fazio, G. G. +6 more
We present subarcsecond angular resolution, high-Strehl ratio mid-IR adaptive optics images of the powerful OH/IR source and cool hypergiant NML Cyg at 8.8, 9.8, and 11.7 µm. These images reveal once more the complexity in the dusty envelope surrounding this star. We spatially resolve the physical structures (radius ~ 0farcs14, ~240 AU adopt…
Suzaku Observation of the Giant Radio Galaxy 3C 326
Isobe, Naoki; Gandhi, Poshak; Tashiro, Makoto S. +5 more
A Suzaku observation of a giant radio galaxy, 3C 326, which has a physical size of about 2 Mpc, was conducted on 2008 January 19-21. In addition to several X-ray sources, diffuse emission was significantly detected and associated with its west lobe, but the east lobe was contaminated by an unidentified X-ray source WARP J1552.4+2007. After careful…
High-dispersion Spectrum of the Halo Planetary Nebula DdDm 1
Izumiura, Hideyuki; Otsuka, Masaaki; Hyung, Siek +2 more
Using the High Dispersion Spectrograph (HDS) at the Subaru Telescope, we secured the high-resolution line spectra in the 3600-7500 Å wavelength range of the Galactic halo planetary nebula DdDm 1. We also analyzed the Hubble Space Telescope Faint Object Spectrograph data in the 1200-6730 Å wavelength range. The diagnostic results indicate the elect…
Grain Growth and Global Structure of the Protoplanetary Disk Associated with the Mature Classical T Tauri Star, PDS 66
Pascucci, Ilaria; Schneider, Glenn; Hines, Dean C. +4 more
We present Australia Telescope Compact Array interferometric observations of the old (13 Myr), nearby (86 pc) classical T Tauri star (cTTS), PDS 66. Unresolved 3 and 12 mm continuum emission is detected toward PDS 66, and upper limits are derived for the 3 and 6 cm flux densities. The millimeter-wave data show a spectral slope flatter than that ex…
Mapping the Structure of the Corona Using Fourier Backprojection Tomography
Morgan, Huw; Habbal, Shadia Rifai; Lugaz, Noé
Estimating the structure, or density distribution, of the solar corona from a set of two-dimensional white-light images made by coronagraphs is a critical challenge in coronal physics. This work describes new data-analysis procedures which are used to create global maps of the coronal structure at heights where the corona becomes approximately rad…
Improved Constraints on the Gravitational Lens Q0957+561. I. Weak Lensing
Schrabback, T.; Keeton, C. R.; Bernstein, G. M. +2 more
Attempts to constrain the Hubble constant using the strong gravitational lens system Q0957+561 are limited by systematic uncertainties in the mass model, since the time delay is known very precisely. One important systematic effect is the mass-sheet degeneracy, which arises because strong lens modeling cannot constrain the presence or absence of a…
Constraints on the Intracluster Dust Emission in the Coma Cluster of Galaxies
Onaka, Takashi; Kaneda, Hidehiro; Kitayama, Tetsu +7 more
We have undertaken a search for the infrared emission from the intracluster dust in the Coma cluster of galaxies by the Multiband Imaging Photometer for Spitzer. Our observations yield the deepest mid and far-infrared images of a galaxy cluster ever achieved. In each of the three bands, we have not detected a signature of the central excess compon…
The "Main Sequence" of Explosive Solar Active Regions: Discovery and Interpretation
Moore, Ronald L.; Gary, G. Allen; Falconer, David A. +1 more
We examine the location and distribution of the production of coronal mass ejections (CMEs) and major flares by sunspot active regions in the phase space of two whole-active-region magnetic quantities measured from 1897 SOHO/MDI magnetograms. These magnetograms track the evolution of 44 active regions across the central disk of radius 0.5 R S…
X-ray Sources and their Optical Counterparts in the Galactic Globular Cluster M12 (NGC 6218)
Anderson, Scott F.; Kong, Albert K. H.; Verbunt, Frank +4 more
We study a Chandra X-ray Observatory ACIS-S observation of the Galactic globular cluster M12. With a 26 ks exposure time, we detect six X-ray sources inside the half-mass radius (2farcm16) of which two are inside the core radius (0farcm72) of the cluster. If we assume that these sources are all associated with globular cluster M12, the luminosity …
Chandra Observations of Nuclear X-Ray Emission from Low Surface Brightness Galaxies
Reynolds, C. S.; Das, M.; Vogel, S. N. +2 more
We present Chandra detections of X-ray emission from the active galactic nuclei (AGN) in two giant low surface brightness (LSB) galaxies, UGC 2936 and UGC 1455. Their X-ray luminosities are 1.8 × 1042 ergs s-1 and 1.1 × 1040 ergs s-1 respectively. Of the two galaxies, UGC 2936 is radio loud. Together wit…