Search Publications
Magnetic Variances and Pitch-angle Scattering Times Upstream of Interplanetary Shocks
Zimbardo, Gaetano; Perri, Silvia
Recent observations of power-law time profiles of energetic particles accelerated at interplanetary shocks have shown the possibility of anomalous, superdiffusive transport for energetic particles throughout the heliosphere. Those findings call for an accurate investigation of the magnetic field fluctuation properties at the resonance frequencies …
Silica-rich Bright Debris Disk around HD 15407A
Onaka, Takashi; Fukagawa, Misato; Murakami, Hiroshi +5 more
We report an intriguing debris disk toward the F3V star HD 15407A in which an extremely large amount of warm fine dust (~10-7 M ⊕) is detected. The dust temperature is derived as ~500-600 K and the location of the debris dust is estimated as 0.6-1.0 AU from the central star, a terrestrial planet region. The fractional luminos…
High Angular Resolution Radio Observations of a Coronal Mass Ejection Source Region at Low Frequencies during a Solar Eclipse
Ramesh, R.; Kathiravan, C.; Barve, Indrajit V. +1 more
We carried out radio observations of the solar corona in the frequency range 109-50 MHz during the annular eclipse of 2010 January 15 from the Gauribidanur Observatory, located about 100 km north of Bangalore in India. The radio emission in the above frequency range originates typically in the radial distance range ≈1.2-1.5 R ⊙ in the "…
Characterizing the Atmospheres of Transiting Planets with a Dedicated Space Telescope
Ollivier, M.; Ribas, I.; Encrenaz, T. +12 more
Exoplanetary science is one of the fastest evolving fields of today's astronomical research, continuously yielding unexpected and surprising results. Ground-based planet-hunting surveys, together with dedicated space missions such as Kepler and CoRoT, are delivering an ever-increasing number of exoplanets, over 690, and ESA's Gaia mission will esc…
The Faint-end Slope of the Redshift 5.7 Lyα Luminosity Function
Martin, Crystal L.; Sawicki, Marcin; Dressler, Alan +2 more
Using new Keck DEIMOS spectroscopy, we examine the origin of the steep number counts of ultra-faint emission-line galaxies recently reported by Dressler et al. We confirm six Lyα emitters (LAEs), three of which have significant asymmetric line profiles with prominent wings extending 300-400 km s-1 redward of the peak emission. With thes…
Modeling Extragalactic Foregrounds and Secondaries for Unbiased Estimation of Cosmological Parameters from Primary Cosmic Microwave Background Anisotropy
Doré, O.; Dudley, J.; Knox, L. +5 more
Using the latest physical modeling and constrained by the most recent data, we develop a phenomenological parameterized model of the contributions to intensity and polarization maps at millimeter wavelengths from external galaxies and Sunyaev-Zeldovich effects. We find such modeling to be necessary for estimation of cosmological parameters from Pl…
Characterizing CO Fourth Positive Emission in Young Circumstellar Disks
Herczeg, Gregory J.; Valenti, Jeff A.; Brown, Alexander +5 more
Carbon monoxide is a commonly used IR/submillimeter tracer of gas in protoplanetary disks. We present an analysis of ultraviolet CO emission in Hubble Space Telescope Cosmic Origins Spectrograph spectra for 12 Classical T Tauri stars (CTTSs). Several ro-vibrational bands of the CO A 1Π-X 1Σ+ (Fourth Positive) elect…
Cosmic Origins Spectrograph Observations of Warm Intervening Gas at z ~ 0.325 toward 3C 263
Savage, Blair D.; Wakker, Bart P.; Narayanan, Anand
We present HST/COS high-S/N observations of the z = 0.32566 multiphase absorber toward 3C 263. The Cosmic Origins Spectrograph (COS) data show absorption from H I (Lyα to Lyθ), O VI, C III, N III, Si III, and C II. The Ne VIII in this absorber is detected in the FUSE spectrum along with O III, O IV, and N IV. The low and intermediate ions are kine…
Revisiting the Chlorine Abundance in Diffuse Interstellar Clouds from Measurements with the Copernicus Satellite
Federman, S. R.; Sheffer, Y.; Moomey, Daniel
We reanalyzed interstellar Cl I and Cl II spectra acquired with the Copernicus satellite. The directions for this study come from those of Crenny & Federman and sample the transition from atomic to molecular-rich clouds where the unique chemistry leading to molecules containing chlorine is initiated. Our profile syntheses relied on up-to-date …
A Lighthouse Effect in Eta Carinae
Madura, Thomas I.; Groh, Jose H.
We present a new model for the behavior of scattered time-dependent, asymmetric near-UV emission from the nearby ejecta of η Car. Using a three-dimensional (3D) hydrodynamical simulation of η Car's binary colliding winds, we show that the 3D binary orientation derived by Madura et al. in 2012 is capable of explaining the asymmetric near-UV variabi…