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Whistlers observed by the Cluster spacecraft outside the plasmasphere
Gurnett, D. A.; Pickett, J. S.; Inan, U. S. +4 more
Lightning generated whistlers are ubiquitous within the plasmasphere at both high and low altitudes, and these waves propagate efficiently in both ducted and nonducted modes. On the other hand, in the magnetospheric region outside the plasmasphere, lightning-generated whistlers are commonly observed at low altitudes (up to ∼6000 km) but only rarel…
Colors of Luminous Bulges in Cluster MS 1054-03 and Field Galaxies at Redshifts z~0.83
Tran, Kim-Vy; Willmer, Christopher N. A.; Im, Myungshin +3 more
Using Hubble Space Telescope images, we separate the bulgelike (dubbed ``pbulge'') and disklike (``pdisk'') components of 71 galaxies in the rich cluster MS 1054-03 and of 21 in the field. Our key finding is that luminous pbulges are very red, with rest-frame U-B~0.45, while predicted colors are bluer by 0.20 mag. Moreover, these very red colors a…
Multiple Outbursts of a Cataclysmic Variable in the Globular Cluster M22
Sumi, T.; MOA Collaboration; Bond, I. A. +19 more
We present a 4 yr light curve of a cataclysmic variable in M22, based on an analysis of accumulated data from the Microlensing Observations in Astrophysics (MOA) microlensing survey. The position of the star coincides with that of a transient event observed by the Hubble Space Telescope (HST) in 1999, originally attributed to microlensing but late…
A serendipitous XMM-Newton observation of the intermediate polar WX Pyx
Schlegel, E. M.
We briefly describe a serendipitous observation of the little-studied intermediate polar WX Pyx using XMM-Newton. The X-ray spin period is 1557.3 s, confirming the optical period published in 1996. An orbital period of ~5.54 h is inferred from the separation of the spin-orbit sidelobe components. The soft and hard band spin-folded light curves are…
Poisson Recoding Of Solar Images For Enhanced Compression
Berghmans, David; Nicula, Bogdan; Hochedez, Jean-François
The amount of useful scientific data that a space-borne telescope produces is often limited by the available telemetry of the platform. General purpose image compression schemes are usually used to compress the image either lossy or losslessly. These schemes do not take into account the fact that pixel values of typical solar images are only known…
Auroral kilometric radiation and magnetosphere-ionosphere coupling process during magnetic storms
Misawa, H.; Tsuchiya, F.; Morioka, A. +8 more
This paper presents an investigation of a magnetosphere-ionosphere (M-I) coupling process during magnetic storms, using observations of auroral kilometric radiation (AKR) in the field-aligned acceleration region and plasma density variation in the plasma sheet. The main phase electron precipitation, which AKR does not accompany, was confirmed as n…
Empirical reconstruction and long-duration tracking of the magnetospheric boundary in single- and multi-spacecraft contexts
Owen, C. J.; Roth, M.; Dunlop, M. W. +3 more
The magnetospheric boundary is always moving, making it difficult to establish its structure. This paper presents a novel method for tracking the motion of the boundary, based on in-situ observations of the plasma velocity and of one or more additional observables. This method allows the moving boundary to be followed for extended periods of time …
Extragalactic globular clusters in the near-infrared. V. IC 4051 and NGC 3311
Hoard, D. W.; Geisler, D.; Hempel, M. +1 more
We present the results of combined optical and near-infrared photometry for the globular cluster systems of the giant ellipticals IC 4051 and NGC 3311. We use the reduced age-metallicity degeneracy in (V-I) vs. (V-H) color-color diagrams to derive the cumulative age distribution within the red sub-population of globular clusters and to search for …
Clearing up the clouds around NGC 4151: evidence of a highly ionized absorber
Piro, L.; de Rosa, A.; Perola, G. C. +1 more
The Seyfert 1 galaxy NGC 4151 is characterized by complex X-ray absorption, well described by a dual absorber, composed of a uniform mildly ionized gas and a cold system that partially covers the central source. However, in one of the 5 BeppoSAX observations, the spectrum shows two peculiar features. An absorption feature is detected around 8.5-9 …
Photometric Redshift of the GRB 981226 Host Galaxy
Christensen, L.; Gorosabel, J.; Hjorth, J.
No optical afterglow was found for the dark burst GRB 981226, and hence no absorption redshift has been obtained. We here use ground-based and space imaging observations to analyze the spectral energy distribution (SED) of the host galaxy. By comparison with synthetic template spectra, we determine the photometric redshift of the GRB 981226 host t…