Search Publications
Transit Target Selection Using Reduced Proper Motions
Gould, Andrew; Morgan, Christopher W.
In searches for planetary transits in the field, well over half of the survey stars are typically giants or other stars that are too large to permit straightforward detection of planets. For all-sky searches of bright V<~11 stars, the fraction is ~90%. We show that the great majority of these contaminants can be removed from the sample by analy…
Coronal Structure of a Flaring Region and Associated Coronal Mass Ejection
Kundu, M. R.; Manoharan, P. K.
We report the multiwavelength investigations of an eruptive flare event that occurred on 2001 April 2 at about 11 UT. The manifestations associated with this flare event have been studied from the near-Sun region to about 0.5 AU. The Hα images from the Meudon Spectroheliograph reveal a fast spectacular eruption of plasmoids from the flare site to …
The Evolution of Vector Magnetic Fields in an Emerging Flux Region
Kubo, M.; Lites, B. W.; Shimizu, T.
Collaborative observations of NOAA Active Region 9231 were carried out during 9 days in 2000 November using the Advanced Stokes Polarimeter (ASP), Yohkoh/SXT, TRACE, and SOHO/MDI, in order to record the evolution of the photospheric magnetic field and its related coronal response. During this period an emerging flux region (EFR) appeared in the ph…
The origin of the Fe K features in Markarian 205 and Markarian 509
Page, M. J.; Salvi, N. J.; Davis, S. W.
We examine the 3-10 keV EPIC spectra of Mrk 205 and 509 to investigate their Fe K features. The most significant feature in the spectra of both objects is an emission line at 6.4 keV. The spectra can be adequately modelled with a power law and a relatively narrow (σ < 0.2 keV) Fe Kα emission line. Better fits are obtained when an additional Gau…
A new model of solar EUV irradiance variability 2. Comparisons with empirical models and observations and implications for space weather
Mariska, J. T.; Warren, H. P.; Bishop, J. +1 more
Motivated by the need for reliable specification of the Sun's electromagnetic radiation in the extreme ultraviolet (EUV) spectrum, we have developed a new model of solar EUV irradiance variability at wavelengths from 50 to 1200 Å. Solar images are used to quantify changes in the sources of EUV irradiance during the solar cycle. Optically thin EUV …
Wavelike Properties of Solar Supergranulation Detected in Doppler Shift Data
Schou, J.
Recently, Gizon, Duvall, & Schou suggested that supergranulation has a wavelike component. In this Letter, I show that the same phenomenon can be observed using surface Doppler shift data, thereby confirming their observations, which were made using a helioseismic time-distance technique. In addition to confirming those results, I show that th…
The Trumpler 14 photodissociation region in the Carina Nebula
Poglitsch, A.; Schneider, N.; Cox, P. +4 more
We report the results of observations of the fine-structure emission lines [C II] 158 µm and [O I] 63 µm using FIFI on the Kuiper Airborne Observatory (KAO) and the Long Wavelength Spectrometer (LWS) on board ISO, towards the molecular cloud associated with the stellar cluster Trumpler 14 (Tr 14) in the Carina Nebula. These data are co…
The EUV helium spectrum in the quiet Sun: A by-product of coronal emission?
Andretta, V.; Del Zanna, G.; Jordan, S. D.
In this paper we test one of the mechanisms proposed to explain the intensities and other observed properties of the solar helium spectrum, and in particular of its Extreme-Ultraviolet (EUV) resonance lines. The so-called Photoionisation-Recombination (P-R) mechanism involves photoionisation of helium atoms and ions by EUV coronal radiation, follo…
Abundant gas-phase H2O in absorption toward massive protostars
van Dishoeck, E. F.; Boonman, A. M. S.
We present infrared spectra of gas-phase H2O around 6 mu m toward 12 deeply embedded massive protostars obtained with the Short Wavelength Spectrometer on board the Infrared Space Observatory (ISO). The nu2 ro-vibrational band has been detected toward 7 of the sources and the excitation temperatures indicate an origin in the …
The recent X-ray history of NGC 5506
Perola, G. C.; Bianchi, S.; Guainazzi, M. +2 more
We present a detailed discussion of the spectral and spatial components of NGC 5506, based on XMM-Newton, Chandra and BeppoSAX observations. The overall picture consists of a nucleus absorbed by cold gas with column density of ~1022 cm-2 and surrounded by a Compton-thick torus, whose existence is inferred by a cold reflection…