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Fe XIX observations of active region brightenings in the corona
Solanki, S. K.; Innes, D. E.; Wang, T. J.
Small flarelike brightenings seen in the hot flare line, Fe XIX, by the spectrometer SUMER on SOHO are analysed. We observe active region coronae about 30 Mm off the limb of the Sun for a period of several days. Brightenings are observed with a frequency 3-14 per hour and their lifetimes range from 5-150 min, with an average of about 25 min. The m…
Martian phase function: Modeling the visible to near-infrared surface photometric function using HST-WFPC2 data
Soderblom, Jason M.; Bell, James F.; Wolff, Michael J. +1 more
Images of Mars in the visible to near-infrared acquired from 1996 to 2005 using the Hubble Space Telescope WFPC2 have been used to model the martian surface photometric function at 502, 673, 953, and 1042 nm. These data range in spatial resolution from 12 to 70 km/pixel at the sub-Earth point, and in phase angle coverage from 0.34° to 40.5°. The W…
The role of the Hall effect in collisionless magnetic reconnection
Nakamura, R.; Scholer, M.; Runov, A. +2 more
A short review of the role of the Hall effect in collisionless reconnection is given in relation to observations in the upper auroral ionosphere during substorm-reconnection events. We clarify the conditions when the Hall effect should be of importance and when the ion inertial length is the responsible scale which is the case for β⊥ &g…
GMOS IFU observations of the stellar and gaseous kinematics in the centre of NGC 1068
Gerssen, Joris; Miller, Bryan W.; Turner, James E. H. +2 more
We present a data cube covering the central 10 arcsec of the archetypal active galaxy NGC 1068 over a wavelength range 4200-5400 Åobtained during the commissioning of the integral field unit (IFU) of the Gemini Multi-object Spectrograph (GMOS) installed on the Gemini-North telescope. The data cube shows a complex emission line morphology in the [O…
The Dust Envelope of the Preplanetary Nebula IRAS 19475+3119
Sahai, Raghvendra; Sarkar, Geetanjali
We present the spectral energy distribution (SED) of the preplanetary nebula, IRAS 19475+3119 (hereafter I 19475), from the optical to the far-infrared. We identify emission features due to crystalline silicates in the ISO SWS spectra of the star. We have fitted the SED of I 19475 using a one-dimensional radiative transfer code and find that a she…
A data-driven Bayesian approach for finding young stellar populations in early-type galaxies from their ultraviolet-optical spectra
Raychaudhury, Somak; Nolan, Louisa A.; Harva, Markus O. +1 more
Efficient predictive models and data analysis techniques for the analysis of photometric and spectroscopic observations of galaxies are not only desirable, but also required, in view of the overwhelming quantities of data becoming available. We present the results of a novel application of Bayesian latent variable modelling techniques, where we ha…
Infalling Faint [O II] Emitters in Abell 851. II. Environment, Kinematics, and Star Formation History
Martin, Crystal L.; Sato, Taro
We report on the local environment, kinematics, and star formation history of [O II]-selected objects in the z~0.4 galaxy cluster Abell 851, using Keck optical spectra. A large fraction (~55%) of cluster [O II] emitters show strong Balmer absorptions (>~4 Å in Hδ equivalent width). These e(a)-type spectra have been attributed to dusty starburst…
Subarcsecond Mid-Infrared Observations of NGC 6240: Limitations of Active Galactic Nucleus-Starburst Power Diagnostics
Egami, E.; Matthews, K.; Soifer, B. T. +3 more
In order to examine the relative importance of powerful starbursts and Compton-thick active galactic nuclei (AGNs) in NGC 6240, we have obtained mid-infrared images and low-resolution spectra of the galaxy with subarcsecond spatial resolution using the Keck telescopes. Despite the high spatial resolution (~200 pc) of our data, no signature of the …
Success rate of predicting the heliospheric magnetic field polarity with Michelson Doppler Imager (MDI) synoptic charts
Liu, Y.; Hoeksema, J. T.; Scherrer, P. H. +1 more
The photospheric and heliospheric magnetic fields have been continuously observed at the L1 point by the Michelson Doppler Imager (MDI) on the Solar and Heliospheric Observatory (SOHO) and Wind and the Advanced Composition Explorer (ACE) spacecraft since 1996. The combined observations of the photospheric and heliospheric magnetic fields make it p…
Automatic classification of eclipsing binaries light curves using neural networks
Sarro, L. M.; Sánchez-Fernández, C.; Giménez, Á.
In this work we present a system for the automatic classification of the light curves of eclipsing binaries. This system is based on a classification scheme that aims to separate eclipsing binary systems according to their geometrical configuration in a modified version of the traditional classification scheme. The classification is performed by a…