Search Publications
Hubble observations of Jupiter’s north-south conjugate ultraviolet aurora
Bonfond, B.; Clarke, J. T.; Gérard, J. -C. +2 more
Comparisons of the northern and southern far ultraviolet (UV) auroral emissions of Jupiter from the Hubble Space Telescope (HST) or any other ultraviolet imager have mostly been made so far on a statistical basis or were not obtained with high sensitivity and resolution. Such observations are important to discriminate between different mechanisms …
Uncertainties in Atomic Data and their Propagation through Spectral Models. I.
Quinet, P.; Gull, T. R.; Kallman, T. R. +4 more
We present a method for computing uncertainties in spectral models, i.e., level populations, line emissivities, and emission line ratios, based upon the propagation of uncertainties originating from atomic data. We provide analytic expressions, in the form of linear sets of algebraic equations, for the coupled uncertainties among all levels. These…
Waiting Times of Quasi-homologous Coronal Mass Ejections from Super Active Regions
Wang, Yuming; Shen, Chenglong; Wang, S. +3 more
Why and how do some active regions (ARs) frequently produce coronal mass ejections (CMEs)? These are key questions for deepening our understanding of the mechanisms and processes of energy accumulation and sudden release in ARs and for improving our space weather prediction capability. Although some case studies have been performed, these question…
Probing the extended gaseous regions of M31 with quasar absorption lines
Turnshek, David A.; Rao, Sandhya M.; York, Donald G. +4 more
We present Hubble Space Telescope Cosmic Origins Spectrograph spectra of 10 quasars located behind M31, selected to investigate the properties of gas associated with its extended disc and high-velocity clouds (HVCs). The sightlines have impact parameters ranging between b = 13 and 112 kpc. No absorption is detected in the four sightlines selected …
An O2If* star found in isolation in the backyard of NGC 3603.
Roman-Lopes, A.
In this Letter, we communicate the identification of a new Galactic O2If* star (MTT 68) isolated at a projected linear distance of 3 pc from the centre of the starburst cluster NGC 3603. From its optical photometry, I computed a bolometric luminosity MBol = -10.7, which corresponds to a total stellar luminosity of 1.5 × 106 L…
A Detailed Spatiokinematic Model of the Conical Outflow of the Multipolar Planetary Nebula NGC 7026
López, J. A.; Steffen, W.; Richer, M. G. +1 more
We present extensive, long-slit, high-resolution coverage of the complex planetary nebula (PN) NGC 7026. We acquired 10 spectra using the Manchester Echelle Spectrometer at San Pedro Martir Observatory in Baja California, Mexico, and each shows exquisite detail, revealing the intricate structure of this object. Incorporating these spectra into the…
On the Possibility to Diagnose the Non-Maxwellian κ-Distributions from the Hinode/EIS EUV Spectra
Dzifčáková, E.; Dudík, J.; Mackovjak, Š.
We investigate the possibility to diagnose the κ-distributions from the EUV spectra observed by the Hinode/EIS spectrometer. Observable lines of the most abundant elements except Fe are considered. Synthetic spectra for the κ-distributions with κ=2 - 10 and the Maxwellian distribution were calculated for a range of temperatures and electron densit…
On the relation between continuum brightness and magnetic field in solar active regions
Danilovic, S.; Schüssler, M.; Cameron, R. H. +1 more
Context. Variations of solar irradiance are mainly determined by the changing coverage of the visible solar disk with magnetic flux concentrations. The relationship between brightness and field strength is an important ingredient for models and reconstructions of irradiance variations.
Aims: We assess the effect of limited observational resol…
HH 222: A Giant Herbig-Haro Flow from the Quadruple System V380 Ori
Kraus, Stefan; Bally, John; Geballe, T. R. +5 more
HH 222 is a giant shocked region in the L1641 cloud, and is popularly known as the Orion Streamers or "the waterfall" on account of its unusual structure. At the center of these streamers are two infrared sources coincident with a nonthermal radio jet aligned along the principal streamer. The unique morphology of HH 222 has long been associated wi…
Large-area [Fe II] Line Mapping of the Supernova Remnant IC 443 with the IRSF/SIRIUS
Onaka, Takashi; Lee, Ho-Gyu; Kaneda, Hidehiro +3 more
We present the results of near-infrared (near-IR) [Fe II] line mapping of the supernova remnant IC 443 with IRSF/SIRIUS, using the two narrow-band filters tuned for the [Fe II] 1.257 µm and [Fe II] 1.644 µm lines. Covering a large area of 30' × 35', our observations reveal that [Fe II] filamentary structures exist all over the remnant,…