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The tidally disturbed luminous compact blue galaxy Mkn 1087 and its surroundings
Esteban, C.; López-Sánchez, Á. R.; Rodríguez, M.
We present new broad-band optical and near-infrared CCD imaging together with deep optical intermediate-resolution spectroscopy of Mkn 1087 and its surrounding objects. We analyze the morphology and colors of the stellar populations of the brightest objects, some of them star-formation areas, as well as the kinematics, physical conditions and chem…
Observations of Water Vapor Outflow from NML Cygnus
Li, Di; Lim, Tanya; Feuchtgruber, Helmut +2 more
We report new observations of the far-infrared and submillimeter water vapor emission of NML Cygnus based on data gathered with the Infrared Space Observatory and the Submillimeter Wave Astronomy Satellite. We compare the emission from NML Cyg to that previously published for VY CMa and W Hya in an attempt to establish the validity of recently pro…
Gamma-ray all-sky imaging with the Burst and Transient Source Experiment
Hill, A. B.; Knödlseder, J.; Bird, A. J. +6 more
The BATSE mission aboard CGRO monitored the whole sky in the 20 keV-1 MeV energy band continuously from April 1991 until June 2000. Although BATSE had very poor intrinsic angular resolution, the data can be used to survey the entire soft gamma-ray sky with <1° angular resolution and ∼mCrab sensitivity by using the Earth occultation m…
The XMM-Newton observation of GRB 040106: Evidence for an afterglow in a wind environment
Piro, L.; De Pasquale, M.; Gendre, B.
We present the XMM-Newton observation of GRB 040106. From the X-ray spectral index and temporal decay, we argue that the afterglow is consistent with a fireball expanding in a wind environment. A constant density environment is excluded by the data. This is one of the very few cases in which this conclusion can be drawn.
Physical Structure of Planetary Nebulae. III. The Large and Evolved NGC 1360
Guerrero, Martín A.; Chu, You-Hua; Gruendl, Robert A. +1 more
NGC 1360 is a large planetary nebula (PN) without an obvious shell morphology. We have analyzed Hα images and high-dispersion echelle spectra of NGC 1360 in order to construct spatio-kinematic models and to determine its density distribution. The best-fit model indicates that NGC 1360 is a prolate ellipsoidal shell whose major axis is twice as lon…
Cosmic Filaments in Superclusters
Miller, Eric D.; Bregman, Joel N.; Dupke, Renato A.
Large-scale structure calculations show that modest overdensity filaments will connect clusters of galaxies and these filaments are reservoirs of baryons, mainly in gaseous form. To determine whether such filaments exist, we have examined the UV absorption line properties of three active galactic nuclei (AGNs) projected behind possible filaments i…
The Effects of Periodically Gapped Time Series on Cross-Correlation Lag Determinations
Maraschi, L.; Treves, A.; Celotti, A. +2 more
The three bright TeV blazars Mrk 421, Mrk 501, and PKS 2155-304 are highly variable in synchrotron X-ray emission. In particular, these sources can exhibit variable time lags between flux variations at different X-ray energy bands. However, there are a number of issues that may significantly bias lag determinations. Edelson et al. (2001) recently …
Optical and IUE Spectra of the Planetary Nebula NGC 7026
Feibelman, Walter A.; Hyung, Siek
We investigated spectroscopic data of the extended planetary nebula NGC 7026 in the wavelengths 3700-10,050 Å, secured with the Hamilton Echelle Spectrograph at Lick Observatory. This optical wavelength spectrum has been analyzed along with the International Ultraviolet Explorer (IUE) UV spectral data. The diagnostic diagram indicates that the pla…
Detection of Atomic Chlorine in Io's Atmosphere with the Hubble Space Telescope GHRS
Feldman, Paul D.; Strobel, Darrell F.; McGrath, Melissa A. +1 more
We report the detection of atomic chlorine emissions in the atmosphere of Io using Hubble Space Telescope observations with the Goddard High Resolution Spectrograph (GHRS). The Cl I λ1349 dipole allowed and Cl I] λ1386 forbidden transition multiplets are detected at a signal-to-noise ratio of 6 and 10, respectively, in a combined GHRS spectrum acq…
Far-Ultraviolet Observations of RR Lyrae Stars in the Core of NGC 1851
Anderson, Scott F.; Homer, Lee; Margon, Bruce +1 more
There are extraordinarily few far-ultraviolet (FUV) observations of RR Lyrae stars in the literature. We present Hubble Space Telescope (HST) FUV (~1600 Å) imaging of the core of the globular cluster NGC 1851. Eleven new variables with light curves consistent with those of RR Lyrae stars are discovered, increasing the total number of RR Lyrae know…