English
Related papers

Related papers: Testing the FR I/BL Lac unifying model with HST ob…

200 papers

Many of the compact extragalactic radio sources that are used as fiducial points to define the celestial reference frame are known to have proper motions detectable with long-term geodetic/astrometric Very Long Baseline Interferometry…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-16 A. Moór , S. Frey , S. B. Lambert , O. Titov , J. Bakos

We examine the relative orientation of radio jets and dusty tori surrounding the AGN in powerful radio galaxies at z > 1. The radio core dominance R = P(20 GHz) /P(500 MHz) serves as an orientation indicator, measuring the ratio between the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 G. Drouart , C. De Breuck , J. Vernet , R. A. Laing , N. Seymour , D. Stern , M. Haas , E. A. Pier , B. Rocca-Volmerange

We discuss CO spectral line data of a volume-limited sample of 23 nearby (z<0.03) low luminosity radio galaxies, selected from the B2 catalogue. We investigate whether the CO properties of our sample are correlated with the properties of…

We present the results of EVN and MERLIN 5 GHz observations of nine ultra-high-energy synchrotron peak BL Lacs (UHBLs) selected as all BL Lacs with \textbf{log ($\nu_{\rm peak}/ \rm Hz)>20$} from Nieppola et al.. The radio structure was…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Zhongzu Wu , D. R. Jiang , Minfeng Gu

We explore the implications of our optical spectroscopic survey of 3CR radio sources with z<0.3 for the unified model (UM) for radio-loud AGN, focusing on objects with a FRII radio morphology. The sample contains 33 high ionization galaxies…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Ranieri D. Baldi , Alessandro Capetti , Sara Buttiglione , Marco Chiaberge , Annalisa Celotti

In the unified schemes for extragalactic radio sources, the quasars and BL Lac objects are intrinsically similar to the Fanaroff-Riley class II and I radio galaxies respectively, but appear to be different because they are viewed at…

Astrophysics · Physics 2009-10-31 D. J. Saikia

Using HST NICMOS 2 observations we have measured 1.6-micron near infrared nuclear luminosities of 100 3CR radio galaxies with z<0.3, by modeling and subtracting the extended emission from the host galaxy. We performed a multi-wavelength…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 R. D. Baldi , M. Chiaberge , A. Capetti , W. Sparks , F. D. Macchetto , C. P. O'Dea , D. J. Axon , S. A. Baum , A. C. Quillen

We consider archival ROSAT and HST observations of five FRI radio galaxies and isolate their nuclear emission from that of the host galaxy. This enable us to determine the Spectral Energy Distributions (SED) of their nuclei spanning from…

Astrophysics · Physics 2009-10-31 A. Capetti , E. Trussoni , A. Celotti , L. Feretti , M. Chiaberge

In the frame of unification schemes for radio-loud active galactic nuclei (AGNs), FR I radio galaxies are believed to be BL Lacertae (BL Lac) objects with the relativistic jet misaligned to our line of sight, and FR II radio galaxies…

Astrophysics of Galaxies · Physics 2009-11-13 Ya-Di Xu , Xinwu Cao , Qingwen Wu

We have observed 28 sources selected from the 1Jy sample of BL Lac objects (Stickel et al. 1991) with the Very Large Array (VLA) in A, B and D configurations at 1.36, 1.66 and 4.85 GHz, and/or with the Westerbork Synthesis Radio Telescope…

Astrophysics · Physics 2009-10-31 P. Cassaro , C. Stanghellini , M. Bondi , D. Dallacasa , R. Della Ceca , R. A. Zappala`

We present Hubble Space Telescope images of 11 high redshift radio galaxies (between $z=2.3$ and $z=3.6$). The galaxies were observed with the WFPC2 camera in a broad band filter (F606W or F707W, roughly equivalent to V or R-band), for 2…

Hubble Space Telescope (HST) WFPC-2 I-band (F814W) images of three X-ray selected BL Lacertae objects (MS1221.8+2452, MS1407.9+5954, & MS2143.4+0704) reveal that each of these BL Lac objects is well-centered in an extended nebulosity that…

Astrophysics · Physics 2011-03-03 Buell T. Jannuzi , Brian Yanny , Chris Impey

Previously, a multi-wavelength (2cm, 4cm and 6cm) polarization study by Gabuzda, Murray and Cronin (2004) showed systematic Faraday Rotation gradients across the parsec-scale jets of several BL Lac objects, interpreted as evidence for…

Astrophysics · Physics 2007-08-03 Mehreen Mahmud , Denise Gabuzda

We have identified a large (~200 kpc), powerful double radio source whose host galaxy is clearly a disk and most likely a spiral. This FR I radio galaxy is located very near the center of the RC 0 cluster Abell 428. The existence of such an…

Astrophysics · Physics 2009-10-31 Michael J. Ledlow , Frazer N. Owen , Min S. Yun , John M. Hill

We have compared far-ultraviolet (FUV), near-ultraviolet (NUV), and Halpha measurements for star forming regions in 21 galaxies, in order to characterise the properties of their discs at radii beyond the main optical radius (R25). In our…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Q. E. Goddard , R. C. Kennicutt , E. V. Ryan-Weber

BL Lac objects are active nuclei, hosted in massive elliptical galaxies, the emission of which is dominated by a relativistic jet closely aligned with the line of sight. This implies the existence of a parent population of sources with a…

High Energy Astrophysical Phenomena · Physics 2016-11-26 Renato Falomo , Elena Pian , Aldo Treves

We present VLA and first-epoch VLBA observations that are part of a program to study the parsec-scale radio structure of a sample of fifteen high-energy-peaked BL Lacs (HBLs). The sample was chosen to span the range of logarithmic X-ray to…

Astrophysics · Physics 2009-11-07 T. A. Rector , D. C. Gabuzda , J. T. Stocke

We present an overview of new HST imaging polarimetry of six nearby radio galaxies with optical jets. These observations triple the number of extragalactic jets with subarcsecond-resolution optical polarimetry. We discuss the polarization…

In previous papers we have discussed high-resolution observations of a large sample of powerful radio galaxies with z<0.3. Jets are detected in up to 80 per cent of the sample, and radio cores in nearly all the objects; in addition, we are…

Astrophysics · Physics 2009-10-30 M. J. Hardcastle , P. Alexander , G. G. Pooley , J. M. Riley

We present new optical and near-IR spectroscopy as well as new high dynamic range, arcsecond-resolution VLA radio maps of BL Lacs from the complete radio-selected "1 Jansky" (1Jy) sample (RBLs) for which such data were not previously…

Astrophysics · Physics 2009-11-06 Travis A. Rector , John T. Stocke