Search Publications
New Evidence for the Role of Emerging Flux in a Solar Filament's Slow Rise Preceding Its CME-producing Fast Eruption
Harra, Louise K.; Moore, Ronald L.; Sterling, Alphonse C.
We observe the eruption of a large-scale (~300,000 km) quiet-region solar filament leading to an Earth-directed ``halo'' coronal mass ejection (CME), using data from EIT, CDS, MDI, and LASCO on SOHO and from SXT on Yohkoh. Initially the filament shows a slow (~1 km s-1 projected against the solar disk) and approximately constant velocit…
The Suzaku Observation of the Nucleus of the Radio-loud Active Galaxy Centaurus A: Constraints on Abundances of the Accreting Material
Ptak, A.; Fukazawa, Y.; Kataoka, J. +16 more
A Suzaku observation of the nucleus of the radio-loud AGN Centaurus A in 2005 has yielded a broadband spectrum spanning 0.3-250 keV. The net exposure times after screening were 70 ks per X-ray Imaging Spectrometer (XIS) camera, 60.8 ks for the Hard X-ray Detector (HXD) PIN, and 17.1 ks for the HXD GSO. The hard X-rays are fit by two power laws of …
Embedded Star Formation in the Eagle Nebula with Spitzer GLIMPSE
Indebetouw, R.; Whitney, B. A.; Robitaille, T. P. +5 more
We present new Spitzer photometry of the Eagle Nebula (M16, containing the optical cluster NGC 6611) combined with near-infrared photometry from 2MASS. We use dust radiative transfer models, mid-infrared and near-infrared color-color analysis, and mid-infrared spectral indices to analyze point-source spectral energy distributions, select candidate…
Resolving the Stellar Populations in the Circumnuclear Ring of NGC 7469
Colina, L.; Knapen, J. H.; Díaz-Santos, T. +2 more
We investigate the stellar populations in the star-forming ring of the luminous infrared galaxy NGC 7469. We use HST multiwavelength (UV through NIR) imaging complemented with new K-band ground-based long-slit spectroscopy, and mid-IR and radio maps from the literature. SEDs and evolutionary synthesis models have been used to characterize the star…
Validation of Time-Distance Helioseismology by Use of Realistic Simulations of Solar Convection
Zhao, Junwei; Kosovichev, Alexander G.; Georgobiani, Dali +3 more
Recent progress in realistic simulations of solar convection have given us an unprecedented opportunity to evaluate the robustness of solar interior structures and dynamics obtained by methods of local helioseismology. We present results of testing the time-distance method using realistic simulations. By computing acoustic wave propagation time an…
Swift X-Ray Observations of Classical Novae
Schmitt, J. H. M. M.; Ness, J. -U.; Gehrels, N. +5 more
The new γ-ray burst (GRB) mission Swift has obtained pointed observations of several classical novae in outburst. We analyzed all the observations of classical novae from the Swift archive up to 2006 June 30. We analyzed usable observations of 12 classical novae and found 4 nondetections, 3 weak sources, and 5 strong sources. This includes detecti…
On the Size of Structures in the Solar Corona
DeForest, C. E.
Fine-scale structure in the corona appears not to be well resolved by current imaging instruments. Assuming this to be true offers a simple geometric explanation for several current puzzles in coronal physics, including the apparent uniform cross section of bright threadlike structures in the corona, the low EUV contrast (long apparent scale heigh…
Feedback in the Antennae Galaxies (NGC 4038/9). I. High-Resolution Infrared Spectroscopy of Winds from Super Star Clusters
Graham, James R.; Gilbert, Andrea M.
We present high-resolution (R~24,600) near-IR spectroscopy of the youngest super star clusters (SSCs) in the prototypical starburst merger, the Antennae galaxies. These SSCs are young (3-7 Myr old) and massive (105-107 Msolar for a Kroupa initial mass function), and their spectra are characterized by broad, extende…
Measuring PAH Emission in Ultradeep Spitzer IRS Spectroscopy of High-Redshift IR-Luminous Galaxies
Frayer, D. T.; Scott, D.; Chary, R. +9 more
The study of the dominant population of high-redshift IR-luminous galaxies (1011-1012 Lsolar at 1<z<3), requires observation of sources at the ~0.1 mJy level in the mid-IR. We present the deepest spectra taken to date with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope. We targeted two faint (…
The Chemical Distribution in a Subluminous Type Ia Supernova: Hubble Space Telescope Images of the SN 1885 Remnant
Wheeler, J. Craig; Fesen, Robert A.; Hamilton, Andrew J. S. +4 more
SN 1885 was a probable subluminous SN Ia that occurred in the bulge of the Andromeda galaxy, M31, at a projected location 16" from the nucleus. Here we present and analyze Hubble Space Telescope images of the SN 1885 remnant seen in absorption against the M31 bulge via the resonance lines of Ca I, Ca II, Fe I, and Fe II. Viewed in Ca II H and K li…