Search Publications
Hubble Space Telescope Observations of Dusty Filaments in Hercules A: Evidence for Entrainment
Perley, R.; O'Dea, C. P.; Cotton, W. +3 more
We present U-, V-, and I-band images of the host galaxy of Hercules A (3C 348) obtained with HST/WFC3/UVIS. We find a network of dusty filaments which are more complex and extended than seen in earlier Hubble Space Telescope (HST) observations. The filaments are associated with a faint blue continuum light (possibly from young stars) and faint Hα …
Modeling Solar Oscillation Power Spectra. II. Parametric Model of Spectral Lines Observed in Doppler-velocity Measurements
Jefferies, Stuart M.; Vorontsov, Sergei V.
We describe a global parametric model for the observed power spectra of solar oscillations of intermediate and low degree. A physically motivated parameterization is used as a substitute for a direct description of mode excitation and damping as these mechanisms remain poorly understood. The model is targeted at the accurate fitting of power spect…
Hot Plasma Associated with a Coronal Mass Ejection
Raymond, J. C.; Landi, E.; Hara, H. +1 more
We analyze coordinated observations from the EUV Imaging Spectrometer (EIS) and X-Ray Telescope (XRT) on board Hinode of an X-ray Plasma Ejection (XPE) that occurred during the coronal mass ejection (CME) event of 2008 April 9. The XPE was trailing the CME core from behind, following the same trajectory, and could be identified both in EIS and XRT…
Observations and Models of Slow Solar Wind with Mg9 + Ions in Quiescent Streamers
Abbo, L.; Giordano, S.; Ofman, L.
Quiescent streamers are characterized by a peculiar UV signature as pointed out by the results from the observations of the Ultraviolet and Coronograph Spectrometer (UVCS) on board SOHO: the intensity of heavy-ion emission lines (such as O VI) shows dimmer core relative to the edges. Previous models show that the structure of the heavy-ion streame…
The First Circumstellar Disk Imaged in Silhouette at Visible Wavelengths with Adaptive Optics: MagAO Imaging of Orion 218-354
Close, Laird M.; Males, Jared R.; Morzinski, Katie M. +11 more
We present high-resolution adaptive optics (AO) corrected images of the silhouette disk Orion 218-354 taken with Magellan AO (MagAO) and its visible light camera, VisAO, in simultaneous differential imaging mode at Hα. This is the first image of a circumstellar disk seen in silhouette with AO and is among the first visible light AO results in the …
Difference in the Spatial Distribution between H2O and CO2 Ices in M 82 Found with AKARI
Oyabu, Shinki; Onaka, Takashi; Yamagishi, Mitsuyoshi +5 more
With AKARI, we obtain the spatially resolved near-infrared (NIR) (2.5-5.0 µm) spectra for the nearby starburst galaxy M 82. These spectra clearly show absorption features due to interstellar ices. Based on the spectra, we created the column density maps of H2O and CO2 ices. As a result, we find that the spatial distribu…
The Circumnuclear Star Formation Environment of NGC 6946: Br γ and H2 Results from Keck Integral Field Spectroscopy
Meier, David S.; Turner, Jean L.; Beck, Sara C. +2 more
We present a three-dimensional data cube of the K-band continuum and the Br γ, H2 S(0), and S(1) lines within the central 18.''5 × 13.''8 (520 pc × 390 pc) region of NGC 6946. Data were obtained using OSIRIS, a near-infrared Integral Field Spectrograph at Keck Observatory, with Laser Guide Star Adaptive Optics. The 0.''3 resolution allo…
Witnessing the Differential Evolution of Disk Galaxies in Luminosity and Size via Gravitational Lensing
Crampton, David; Simard, Luc; Peng, Chien +1 more
We take advantage of the magnification in size and flux of a galaxy provided by gravitational lensing to analyze the properties of 62 strongly lensed galaxies from the Sloan Lens ACS (SLACS) Survey. The sample of lensed galaxies spans a redshift range of 0.20 <= z <= 1.20 with a median redshift of z = 0.61. We use the lens modeling code LENS…
Joint Suzaku and XMM-Newton Spectral Analysis of the Southwest Cygnus Loop
Leahy, Denis; Hassan, Mohammed
We carry out a joint spectral analysis of the Cygnus Loop using data from all six detectors combined from Suzaku and XMM-Newton. This had not been done before, but if a spectral model is physically realistic, it is required that it be consistent with data from different instruments. Thus, our results are an important verification of spectral model…
Near-infrared Spectroscopy of Infrared-excess Stellar Objects in the Young Supernova Remnant G54.1+0.3
Koo, Bon-Chul; Moon, Dae-Sik; Kim, Hyun-Jeong
We present the results of broadband near-infrared spectroscopic observations of the recently discovered mysterious stellar objects in the young supernova remnant G54.1+0.3. These objects, which show significant mid-infrared-excess emission, are embedded in a diffuse loop structure of ~1' in radius. Their near-infrared spectra reveal characteristic…