Search Publications
Discovery of a Symmetrical Highly Collimated Bipolar Jet in Hen 2-90
Sahai, Raghvendra; Nyman, Lars-Åke
Using the Hubble Space Telescope, we have obtained Hα imaging of the object Hen 2-90, which has long been classified as a planetary nebula (PN). We find that the morphology of Hen 2-90 does not look like that of any known PN, but resembles that of a classical young stellar object (YSO)-a bipolar nebula bisected by a flaring disklike structure and …
Comparison of Transient Network Brightenings and Explosive Events in the Solar Transition Region
Wang, Haimin; Chae, Jongchul; Schühle, Udo +2 more
The relation between transient network brightenings, known as blinkers, and explosive events is examined based on coordinated quiet Sun observations in the transition region line O V λ630 recorded by the Coronal Diagnostic Spectrometer (CDS), in the transition region line Si IV λ1402 recorded by the Solar Ultraviolet Measurements of Emitted Radiat…
Far Ultraviolet Spectroscopic Explorer Observations of the Low-Redshift Lyβ Forest
Jenkins, Edward B.; York, Donald G.; Sembach, Kenneth R. +10 more
We describe a moderate-resolution (20-25 km s-1) Far Ultraviolet Spectroscopic Explorer (FUSE) study of the low-redshift intergalactic medium. We report on studies of seven extragalactic sight lines and 12 Lyβ absorbers that correspond to Lyα lines detected by Hubble Space Telescope (HST)/Goddard High Resolution Spectrograph and Space T…
Local Luminosity Function at 15 Microns and Galaxy Evolution Seen by ISOCAM 15 Micron Surveys
Xu, Cong
A local luminosity function at 15 µm is derived using the bivariate (15 µm vs. 60 µm luminosity) method, based on the newly published ISOCAM LW3 band (15 µm) survey of the very deep IRAS 60 µm sample in the north ecliptic pole region (NEPR). New IRAS 60 µm fluxes are obtained using the SCANPI/SUPERSCANPI softwar…
Hydrogen Lyα Absorption Predictions by Boltzmann Models of the Heliosphere
Zank, Gary P.; Wood, Brian E.; Müller, Hans-Reinhard
We use self-consistent kinetic/hydrodynamic models of the heliosphere to predict H I Lyα absorption profiles for various lines of sight through the heliosphere. These results are compared with Lyα absorption lines of six nearby stars observed by the Hubble Space Telescope. The directions of these lines of sight range from nearly upwind (36 Oph) to…
The Mass Function of Main-Sequence Stars in NGC 6397 from Near-Infrared and Optical High-Resolution Hubble Space Telescope Observations
Paresce, Francesco; De Marchi, Guido; Pulone, Luigi
We have investigated the properties of the stellar mass function in the globular cluster NGC 6397 through the use of a large set of Hubble Space Telescope (HST) observations. The latter include existing WFPC 2 images in the V and I bands, obtained at ~4.5‧ and 10' radial distances, as well as a series of deep images in the J and H bands obtained w…
High-Velocity Collimated Outflows in Planetary Nebulae: NGC 6337, HE 2-186, and K4-47
Corradi, Romano L. M.; Gonçalves, Denise R.; Villaver, Eva +4 more
We have obtained narrowband images and high-resolution spectra of the planetary nebulae NGC 6337, He 2-186, and K4-47 with the aim of investigating the relation between their main morphological components and several low-ionization features present in these nebulae. The data suggest that NGC 6337 is a bipolar PN seen almost pole-on, with polar vel…
Interplanetary and Interacting Protons Accelerated in a Parallel Shock Wave
Laitinen, T.; Vainio, R.; Kocharov, L.
We present a test-particle model of diffusive shock acceleration on open coronal field lines based on one-dimensional diffusion-convection equation with finite upstream and downstream diffusion regions. We calculate the energy spectrum of protons escaping into the interplanetary space and that of protons interacting with the subcoronal material pr…
The Hubble Space Telescope Survey of BL Lacertae Objects. IV. Infrared Imaging of Host Galaxies
Calzetti, Daniela; Urry, C. Megan; O'Dowd, Matthew +2 more
The Hubble Space Telescope NICMOS Camera 2 was used for H-band imaging of 12 BL Lacertae objects taken from the larger sample observed with the WFPC2 in the R band by Urry and coworkers and Scarpa and coworkers. Ten of the 12 BL Lacs are clearly resolved, and the detected host galaxies are large, bright ellipticals with average absolute magnitude …
Constraints on the Evolution of S0 Galaxies in Rich Clusters at Moderate Redshift
Smail, Ian; Couch, Warrick J.; Jones, Lewis
We combine morphological classifications from deep Hubble Space Telescope (HST) imaging of a sample of three clusters at z=0.31 and a further nine clusters at z=0.37-0.56 with existing spectroscopic observations of their elliptical (E) and S0 populations, in order to study the relative spectral properties of these two galaxy types. We have also us…