Search Publications
HST NICMOS imaging of z∼2-3 radio-quiet quasars
Calzetti, D.; Lehnert, M.; Ridgway, S. +1 more
We will present the results of a NICMOS H-band imaging survey of a small sample of z∼2-3 radio-quiet quasars. We have resolved extension in at least four of five objects and find evidence for a wide range in the morphologies and magnitudes of these hosts. The host galaxy luminosities range from sub- L ∗ to about 4 L ∗, with m…
Spectral energy distributions of five FR I radio galaxies
Capetti, A.; Chiaberge, M.; Celotti, A. +2 more
We discuss the multi-wavelength properties of the radio galaxies 3C 31, 3C 264, 3C 270, 3C 465 and NGC 7052. The data have been deduced from observations with the VLBI/VLA arrays, HST and ROSAT. The SED of these sources, when compared with that of BL Lacs shows that beaming effects are important, but are not enough—in the simplest scenario—to expl…
Hubble space telescope observations of BL Lacertae environments
Urry, C. Megan; O'Dowd, Matthew; Scarpa, Riccardo +3 more
We analyze images of BL Lacertae objects obtained with the Hubble Space Telescope WFPC2 and the F814W filter. The nine objects cover a redshift range of 0.19 to 0.997. The relatively deep images are sufficient to detect galaxies at least one magnitude below MI* (-21.4) and in most cases to three magnitudes below M*. Galaxy enhancement o…
HST imaging of radio galaxies at /z=0.2: a comparison with quasar hosts and normal ellipticals
McLure, R. J.; Dunlop, J. S.; Hughes, D. H. +3 more
We summarise the results of our recently completed HST R-band study of low-redshift (0.1< z<0.25) FRII radio galaxies along with the host galaxies of quasars of similar redshifts. We find that, like radio galaxies, the hosts of radio-loud quasars and all but the least luminous radio-quiet quasars are massive elliptical galaxies with relative…
The nuclear dust disks of five nearby 3CR elliptical galaxies
Sparks, W. B.; Baum, S. A.; Biretta, J. A. +3 more
We present broad- and narrow-band WFPC2 images of the nuclear dust disks and rings of five low- z elliptical galaxies hosting 3C radio sources: NGC 383 (3C 31)/NGC 382, NGC 3862 (3C 264), NGC 4261 (3C 270), UGC 12064 (3C 449), and NGC 7720 (3C 465)/NGC 7720A. We detect resolved line emission in all the disks. In NGC 383, the line emission consists…
An HST emission-line imaging survey of 3CR radio galaxies
Sparks, W. B.; Macchetto, F.; McCarthy, P. J. +4 more
We present narrow-band images of sixty-four 3CR radio sources observed in lines of [OII] 3727 Å, [OIII] 5007 Å, and H α using the WFPC2 camera on-board HST. The images reveal a wide variety of emission lime morphologies, from compact nuclear regions to large-scale emission knots, filaments, and spiral-like structures. Many objects give evidence of…
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…
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…
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…
HST NICMOS and WFPC2 observations of molecular hydrogen and dust in the central galaxies in cluster cooling flows
Mack, Jennifer; Donahue, Megan
We present preliminary results of HST imaging observations of three central galaxies in X-ray luminous clusters of galaxies with putative major cooling flows in their cores: NGC 1275 in the Perseus cluster, Abell 2597, and PKS 0745-19. Narrow-band NICMOS imaging at 2 microns reveals extended, warm ( T∼2000-3000 K) molecular hydrogen structures in …