Search Publications
Host galaxies and the unification of radio-loud AGN
Giavalisco, Mauro; Urry, C. Megan; O'Dowd, Matthew +4 more
Our HST WFPC2 survey of 110 BL Lac objects, from six complete X-ray-, radio-, and optically-selected catalogs, probes the host galaxies of low-luminosity radio sources in the redshift range 0< z<1.35. The host galaxies are luminous ellipticals, well matched in radio power and galaxy magnitude to FR I radio galaxies. Similarly, the host galax…
Filaments and Ionized Gas in the Vicinity of 3C 244.1
Sparks, William B.; Macchetto, F. Duccio; Martel, André R. +1 more
We present results of Hubble Space Telescope observations of the radio galaxy 3C 244.1. The broadband F702W (R) and F555W (V) images (WFPC2/PC) show an elliptical galaxy, and gaseous filaments and blobs surrounding it. In the narrowband ramp filter, dominated by [O III] λ5007, these filaments are bright and have the same morphology as the broadban…
X-ray spectroscopy of supernova remnants
Ballet, Jean; Decourchelle, Anne
The new generation X-ray telescopes launched in 1999 ( Chandra and XMM-Newton) provide for the first time, good spatial and spectral resolution together, allowing to map emission lines of heavy elements in supernova remnants. In young supernova remnants this reflects nucleosynthesis in the progenitor, and gives access (in theory) to the absolute a…
The morphology of nine radio-selected faint galaxies from deep Hubble Space Telescope imaging
Koo, David C.; Roche, Nathan D.; Lowenthal, James D.
Using the Hubble Space Telescope (HST) WFPC2 we perform deep I-band imaging of nine radio-selected [F(8.5 GHz) >=14 µJy] faint galaxies from the Roche, Lowenthal & Koo (2002) sample. Two are also observed in V using HST STIS. Six of the galaxies have known redshifts, in the range 0.4 < z < 1.0. Radial intensity profiles indicate…
New Hipparcos Variables in "The Bright Star Catalogue"
Hoffleit, Dorrit
The Hipparcos mission discovered 5665 new or previously suspected variable stars. Among these are 308 recently named variables common to "The Bright Star Catalogue". The distributions of these HR stars according to types of variation and amplitude are discussed.
HST imaging of nearby CSOs: obscuration and nuclear structures
Stocke, J. T.; Conway, J. E.; Reynolds, C. +2 more
We present 3-band HST imaging of three nearby ( z<0.1) compact symmetric objects: 4C31.04, 1946+708 and 1146+596 (NGC 3894). These objects were chosen for HST observation on the basis of detected HI and molecular line absorption. The images show large amounts of obscuration in each source, well distributed throughout the host galaxies, but some…
Ultraviolet C I Lines in the HgMn Star χ Lupi
Proffitt, Charles R.
We present non-LTE calculations for the ionization equilibrium of C I tailored to match the HgMn star χ Lupi. Comparisons are made with the UV C I lines observed using the Hubble Space Telescope's Goddard High Resolution Spectrograph, as well as with Voyager far-ultraviolet (FUV) measurements of the flux between 1040 and 1200 Å, where C I is the d…
Interactions between the Abell 2597 central radio source and dense gas in its host galaxy
Koekemoer, Anton M.; Baum, Stefi A.; O'Dea, Christopher P. +5 more
We present a detailed HST/WFPC2 study of the complex network of emission-line filaments and blue continuum emission associated with the lobes of the radio source at the center of the nearby strong cooling-flow cluster Abell 2597. This object is a prototypical "blue-lobed" cluster radio galaxy. We discuss ways in which the radio source is interacti…
On the outer boundary of the sunspot penumbra
Kálmán, Béla
Comparison of photographic observations and vector-magnetograph measurements demonstrate that the outer boundary of the sunspot penumbra - even in complex sunspot groups - closely follows the 0.075 T iso-gauss line of the total value of the magnetic field, corresponding approximately to the equipartition value in the photosphere. Radio observation…
Optical positions of 55 radio stars from astrolabe observations from the Yunnan Observatory
Hui, H.; Rui, W.
The observations by the photoelectric astrolabe at Yunnan Observatory relative to the Hipparcos Catalogue and the optical positions of 55 radio stars were obtained from observations between 1991 and 2000. They all resulted from processing the photon counts obtained by means of the astrolabe after the automation of the instrument. There are 46 star…