Search Publications
Missions
Journals
Publication Years
The Volatile Composition of Comet C/2003 K4 (LINEAR) at Near-IR Wavelengths—Comparisons with Results from the NanÇay Radio Telescope and from the Odin, Spitzer, and SOHO Space Observatories
Villanueva, G. L.; Paganini, L.; Mumma, M. J. +2 more
We observed comet C/2003 K4 (LINEAR) using NIRSPEC at the Keck Observatory on UT 2004 November 28, when the comet was at 1.28 AU from the Sun (post-perihelion) and 1.38 AU from Earth. We detected six gaseous species (H2O, OH*, C2H6, CH3OH, CH4, and HCN) and obtained upper limits for three othe…
Earth's Magnetotail
McPherron, Robert L.
Earth's magnetic tail (magnetotail) was discovered 50 years ago by the first spacecraft to fly downstream of Earth. The magnetotail is a complex structure created by the solar wind. The tail is in fact a very dynamic structure with many internal processes and rapid changes. The magnetospheric substorm is the name given to the collection of phenome…
ULF wave electromagnetic energy flux into the ionosphere: Joule heating implications
Angelopoulos, V.; Bonnell, J. W.; Hartinger, M. D. +2 more
Ultralow-frequency (ULF) waves—in particular, Alfvén waves-transfer energy into the Earth's ionosphere via Joule heating, but it is unclear how much they contribute to global and local heating rates relative to other energy sources. In this study we use Time History of Events and Macroscale Interactions during Substorms satellite data to investiga…
Momentum transfer from solar wind to interplanetary field enhancements inferred from magnetic field draping signatures
Lai, H. R.; Russell, C. T.; Jia, Y. D. +2 more
Characterized by a cusp-shaped enhancement in the magnetic field strength, the magnetic structure in the solar wind, called an interplanetary field enhancement (IFE), has been investigated since its discovery. To understand its three-dimensional magnetic field geometry, we study an IFE detected by five spacecraft simultaneously. Field lines are se…
A New Sample of Obscured AGNs Selected from the XMM-Newton and AKARI Surveys
Oyabu, Shinki; Gandhi, Poshak; Awaki, Hisamitsu +4 more
We report a new sample of obscured active galactic nuclei (AGNs) selected from the XMM-Newton serendipitous source and AKARI point-source catalogs. We match X-ray sources with infrared (18 and 90 µm) sources located at | b| \gt 10^\circ to create a sample consisting of 173 objects. Their optical classifications and absorption column densitie…
Probing Magnetic Fields at the Base of the Solar Convection Zone with Meridional Flows
Liang, Zhi-Chao; Chou, Dean-Yi
Solar magnetic fields are responsible for most of the activities on the Sun. Many theories predict that it is generated by a dynamo near the base of the convection zone (BCZ), located at 0.71{R}⊙ . In this study, we use the solar-cycle variations of the meridional flow to probe magnetic field variations near the BCZ. A helioseismic time…
New Mn II energy levels from the STIS-HST spectrum of the HgMn star HD 175640
Castelli, F.; Kurucz, R. L.; Cowley, C. R.
Aims: The NIST database lists several Mn ii lines that were observed in the laboratory but not classified. They cannot be used in spectrum synthesis because their atomic line data are unknown. These lines are concentrated in the 2380-2700 Å interval. We aimed to assign energy levels and log gf values to these lines.
Methods: Semi-empiric…
Candidates source regions of martian meteorites as identified by OMEGA/MEx
Bibring, J. -P.; Poulet, F.; Quantin, C. +3 more
The objective of this study is to identify and map spectral analogues of some key martian meteorites (basaltic shergottites Los Angeles, Shergotty, QUE 94201, lherzolitic shergottite ALH A77005, Nakhla, Chassigny and the orthopyroxenite ALH 84001) in order to localize terrain candidates for their source regions. We develop a best fit procedure to …
Metallicity Distribution Functions of Four Local Group Dwarf Galaxies
Holtzman, Jon; Anthony-Twarog, Barbara J.; Saha, Abhijit +1 more
We present stellar metallicities in Leo I, Leo II, IC 1613, and Phoenix dwarf galaxies derived from medium (F390M) and broad (F555W, F814W) band photometry using the Wide Field Camera 3 instrument on board the Hubble Space Telescope. We measured metallicity distribution functions (MDFs) in two ways, (1) matching stars to isochrones in color-color …
An Emerging Wolf-Rayet Massive Star Cluster in NGC 4449
Johnson, Kelsey E.; Indebetouw, Rémy; Reines, Amy E. +1 more
We present a panchromatic investigation of the partially embedded, emerging massive cluster Source 26 (=S26) in NGC 4449 with optical spectra obtained at Apache Point Observatory and archival Hubble, Spitzer, and Herschel 5 Space Telescope images. First identified as a radio continuum source with a thermal component due to ionized mater…