We consider a pseudodifferential operator defined as follows: Hαφ = ℱ−1[(〈ξ〉α − prα)ℱφ], where 〈ξ〉α (max{|ξ|p, pr})α, and study the Markov process associated with this operator. also analyze first passage time problem Hα for r < 0.

Night side images of Jupiter taken by the Cassini Imaging Science Subsystem (ISS) camera with the Hα filter reveal four lightning clusters; two of them are repeated observations of the same storm. All of these flashes are associated with storm clouds seen a few hours earlier on the day side of Jupiter. Some of the clouds associated with lightning do not extend to the upper troposphere. The repe...

First evidences of IR excess and disk mass accretion (strong Hα emission) around brown dwarfs seem to indicate the existence of circumstellar disks around these sub-stellar objects. Nothing is known at the present time about outflows which potentially might be launched from brown dwarfs, although jets are typically associated with the accretion in standard T Tauri star disks. In this paper we c...

Radio galaxy PKS 1138−262 is a massive galaxy at z = 2.16, located in a dense environment. We have found an overdensity of Lyα emitting galaxies in this field, consistent with a proto-cluster structure associated with the radio galaxy. Recently, we have discovered forty candidate Hα emitters by their excess near infrared narrow band flux. Here, we present infrared spectroscopy of nine of the br...

The NOAO Survey for Ionization in Neutral Gas Galaxies (SINGG) is the largest star formation survey of an H i selected sample. Since the selection is made without regard to optical morphology, it is not biased toward or against “interesting” types of galaxies; thus SINGG is an ideal sample for studying galaxy demographics. Of a sample of 90 extra-galactic sources observed in photometric conditi...

We report sub-mas observations of the Be Shell star ζ Tauri with the Grand Interféromètre à 2 Télescopes (GI2T) on November ’93 and October ’94. In ’93, the Hα line presented a V/R ratio of 0.57 with a central absorption shell component. On October ’94 the Hα line presented a reversed V/R ratio of 1.26 with a shallower absorption component. For both epochs we analysed the amplitude and phase of...

The interaction of high-velocity neutron stars with the interstellar medium produces bow shock nebulae, where the relativistic neutron star wind is confined by ram pressure. We present multi-wavelength observations of the Guitar Nebula, including narrow-band Hα imaging with HST/WFPC2, which resolves the head of the bow shock. The HST observations are used to fit for the inclination of the pulsa...