Search Publications
Ultraviolet Spectra of the C-2003K7 Comet: Evidence for Dust Sublimation in Si and C Lines
Raymond, J. C.; Ciaravella, A.; Giordano, S.
UV spectra of the bright sungrazing comet C-2003K7 detected at 2.37 R sun above the Sun surface by the Ultraviolet Coronagraph Spectrometer (UVCS) during the daily synoptic scan show bright lines of H I Lyα, Si III λ 1206, and C III λ 977. The derived outgassing rate is an order of magnitude larger than those of the other sungrazers obs…
A Multi-wavelength Approach to the Properties of Extremely Red Galaxy Populations. I. Contribution to the Star Formation Rate Density and Active Galactic Nucleus Content
Alexander, D. M.; Mobasher, B.; Messias, H. +3 more
We present a multi-wavelength analysis of the properties of extremely red galaxy (ERG) populations, selected in the GOODS-South/Chandra Deep Field South field. By using all the photometric and spectroscopic information available on large deep samples of extremely red objects (EROs; 645 sources), IRAC EROs (IEROs; 294 sources), and distant red gala…
Scattering Polarization in the Fe I 630 nm Emission Lines at the Extreme Limb of the Sun
Lites, B. W.; Ichimoto, K.; Ishikawa, R. +6 more
Spectro-polarimetric observations with the Solar Optical Telescope onboard Hinode reveal the emission spectrum of the Fe I 630 nm lines at the solar limb. The emission shell extends for less than 1'' thereby making it extremely difficult to detect from ground-based observatories viewing the limb through the Earth's atmosphere. The linear polarizat…
Constraining Three-Dimensional Magnetic Field Extrapolations Using the Twin Perspectives of STEREO
Gallagher, Peter T.; Conlon, Paul A.
The three-dimensional magnetic topology of a solar active region (NOAA 10956) was reconstructed using a linear force-free field extrapolation constrained using the twin perspectives of STEREO. A set of coronal field configurations was initially generated from extrapolations of the photospheric magnetic field observed by the Michelson Doppler Image…
Discovery of a 693.5 s Period in the X-Ray Binary 4U 1820 - 30: A Superhump Interpretation
Chakrabarty, Deepto; Wang, Zhongxiang
The X-ray source 4U 1820-30 in the globular cluster NGC 6624 is known as the most compact binary among the identified X-ray binaries (XRBs). Having an orbital period of 685.0 s, the source consists of a neutron star (NS) primary and likely a 0.06-0.08 M sun white dwarf (WD) secondary. Here, we report on far-ultraviolet (FUV) observation…
A Method for Separating Coronal Mass Ejections from the Quiescent Corona
Morgan, Huw; Habbal, Shadia
A method for separating coronal mass ejections (CMEs) from the quiescent corona in white-light coronagraph images is presented. Such a separation allows the study of CME structure, as well as enabling a study of the quiescent coronal structure, without contamination by the CME. The fact that the large-scale quiescent corona is very close to radial…
Methane Gas Stabilizes Supercooled Ethane Droplets in Titan's Clouds
Wang, Chia C.; Signorell, Ruth; Kathrin Lang, E.
Strong evidence for ethane clouds in various regions of Titan's atmosphere has recently been found. Ethane is usually assumed to exist as ice particles in these clouds, although the possible role of liquid and supercooled liquid ethane droplets has been recognized. Here, we report on infrared spectroscopic measurements of ethane aerosols performed…
Chandra Reveals Variable Multi-component X-ray Emission From FU Orionis
Skinner, Stephen L.; Güdel, Manuel; Briggs, Kevin R. +1 more
FU Orionis is the prototype of a class of eruptive young stars ("FUors") characterized by strong optical outbursts. We recently completed an exploratory survey of FUors using XMM-Newton to determine their X-ray properties, about which little was previously known. The prototype FU Ori and V1735 Cyg were detected. The X-ray spectrum of FU Ori was fo…
The Photospheric Energy and Helicity Budgets of the Flux-injection Hypothesis
Schuck, P. W.
The flux-injection hypothesis for driving coronal mass ejections (CMEs) requires the transport of substantial magnetic energy and helicity flux through the photosphere concomitant with the eruption. Under the magnetohydrodynamics approximation, these fluxes are produced by twisting magnetic field and/or flux emergence in the photosphere. A CME tra…
Emergent Spectra from Disks Surrounding Kerr Black Holes: Effect of Photon Trapping and Disk Self-shadowing
Li, Guang-Xing; Cao, Xinwu; Yuan, Ye-Fei
Based on a new estimation of their thickness, the global properties of relativistic slim accretion disks are investigated in this work. The resulting emergent spectra are calculated using the relativistic ray-tracing method, in which we neglect the self-irradiation of the accretion disk. The angular dependence of the disk luminosity, the effects o…