Search Publications
AKARI Observations of Brown Dwarfs. IV. Effect of Elemental Abundances on Near-infrared Spectra between 1.0 and 5.0 µm
Yamamura, I.; Sorahana, S.
The detection of the CO2 absorption band at 4.2 µm in brown dwarf spectra by AKARI has made it possible to discuss CO2 molecular abundance in brown dwarf atmospheres. In our previous studies, we found an excess in the 4.2 µm CO2 absorption band of three brown dwarf spectra, and suggested that these devi…
Intensity Enhancement of O VI Ultraviolet Emission Lines in Solar Spectra due to Opacity
Doyle, J. G.; Madjarska, M. S.; Mathioudakis, M. +5 more
Opacity is a property of many plasmas. It is normally expected that if an emission line in a plasma becomes optically thick, then its intensity ratio to that of another transition that remains optically thin should decrease. However, radiative transfer calculations undertaken both by ourselves and others predict that under certain conditions the i…
Spatial Nonlocality of the Small-scale Solar Dynamo
Lamb, D. A.; DeForest, C. E.; Howard, T. A.
We explore the nature of the small-scale solar dynamo by tracking magnetic features. We investigate two previously explored categories of the small-scale solar dynamo: shallow and deep. Recent modeling work on the shallow dynamo has produced a number of scenarios for how a strong network concentration can influence the formation and polarity of ne…
Mid-infrared Imaging of the Bipolar Planetary Nebula M2-9 from SOFIA
Sahai, R.; Schoenwald, J.; Lykou, F. +10 more
We have imaged the bipolar planetary nebula M2-9 using SOFIA's FORCAST instrument in six wavelength bands between 6.6 and 37.1 µm. A bright central point source, unresolved with SOFIA's ~4''-5'' beam, is seen at each wavelength, and the extended bipolar lobes are clearly seen at 19.7 µm and beyond. The photometry between 10 and 25 &mic…
Plasma Heating in Solar Flares and their Soft and Hard X-Ray Emissions
Falewicz, R.
In this paper, the energy budgets of two single-loop-like flares observed in X-ray are analyzed under the assumption that nonthermal electrons (NTEs) are the only source of plasma heating during all phases of both events. The flares were observed by RHESSI and GOES on 2002 February 20 and June 2, respectively. Using a one-dimensional (1D) hydrodyn…
An HST COS "SNAPshot" Spectrum of the K Supergiant λ Vel (K4Ib-II)
Ayres, Thomas R.; Harper, Graham M.; Carpenter, Kenneth G. +3 more
We present a far-ultraviolet spectrum of the K4 Ib-II supergiant λ Vel obtained with the Hubble Space Telescope's Cosmic Origins Spectrograph (COS) as a part of the SNAPshot program "SNAPing coronal iron" (GO 11687). The observation covers a wavelength region (1326-1467 Å) not previously recorded for λ Vel at a spectral resolving power of R ~ 20,0…
Density Diagnostics of Coronal Mass Ejection Cores with the Solar Dynamics Observatory/Atmospheric Imaging Assembly
Landi, E.; Miralles, M. P.
In this Letter, we investigate the application of the intensity ratio from pairs of narrow-band images from the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory, the Extreme Ultraviolet (EUV) Imager (EUVI) on board the Sun Earth Connection Coronal and Heliospheric Investigation, and the EUV Imaging Telescope (EIT) on board the …
Young Star Clusters in the Circumnuclear Region of NGC 2110
Durré, Mark; Mould, Jeremy
High-resolution observations in the near infrared show star clusters around the active galactic nucleus (AGN) of the Seyfert 1 NGC 2110, along with a 90 × 35 pc bar of shocked gas material around its nucleus. These are seen for the first time in our imaging and gas kinematics of the central 100 pc with the Keck OSIRIS instrument with adaptive opti…
The Panchromatic Hubble Andromeda Treasury. VI. The Reliability of Far-ultraviolet Flux as a Star Formation Tracer on Subkiloparsec Scales
Bell, Eric F.; Dolphin, Andrew E.; Skillman, Evan D. +6 more
We have used optical observations of resolved stars from the Panchromatic Hubble Andromeda Treasury to measure the recent (<500 Myr) star formation histories (SFHs) of 33 far-UV (FUV)-bright regions in M31. The region areas ranged from ~104 to 106 pc2, which allowed us to test the reliability of FUV flux as a tr…
The X-Ray Zurich Environmental Study (X-ZENS). I. Chandra and XMM-Newton Observations of Active Galactic Nuclei in Galaxies in nearby Groups
Finoguenov, A.; Silverman, J. D.; Carollo, C. M. +4 more
We describe X-ray observations with Chandra and XMM-Newton of 18 M group ~ 1-6 × 1013 M ⊙, z ~ 0.05 galaxy groups from the Zurich ENvironmental Study. The X-ray data aim at establishing the frequency and properties, unaffected by host galaxy dilution and obscuration, of active galactic nuclei (AGNs) in central and …