2012A&A...545A.117L


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.17CEST08:49:36

2012A&A...545A.117L - Astronomy and Astrophysics, volume 545A, 117-117 (2012/9-1)

VLBA monitoring of Mrk 421 at 15 GHz and 24 GHz during 2011.

LICO R., GIROLETTI M., ORIENTI M., GIOVANNINI G., COTTON W., EDWARDS P.G., FUHRMANN L., KRICHBAUM T.P., SOKOLOVSKY K.V., KOVALEV Y.Y., JORSTAD S., MARSCHER A., KINO M., PANEQUE D., PEREZ-TORRES M.A. and PINER G.

Abstract (from CDS):

High-resolution radio observations are ideal for constraining the value of physical parameters in the inner regions of active-galactic-nucleus jets and complement results on multiwavelength (MWL) observations. This study is part of a wider multifrequency campaign targeting the nearby TeV blazar Markarian 421 (z=0.031), with observations in the sub-mm (SMA), optical/IR (GASP), UV/X-ray (Swift, RXTE, MAXI), and γ rays (Fermi-LAT, MAGIC, VERITAS). We investigate the jet's morphology and any proper motions, and the time evolution of physical parameters such as flux densities and spectral index. The aim of our wider multifrequency campaign is to try to shed light on questions such as the nature of the radiating particles, the connection between the radio and γ-ray emission, the location of the emitting regions and the origin of the flux variability. We consider data obtained with the Very Long Baseline Array (VLBA) over twelve epochs (one observation per month from January to December 2011) at 15 GHz and 24 GHz. We investigate the inner jet structure on parsec scales through the study of model-fit components for each epoch. The structure of Mrk 421 is dominated by a compact (∼0.13 mas) and bright component, with a one-sided jet detected out to ∼10 mas. We identify 5-6 components in the jet that are consistent with being stationary during the 12-month period studied here. Measurements of the spectral index agree with those of other works: they are fairly flat in the core region and steepen along the jet length. Significant flux-density variations are detected for the core component. From our results, we draw an overall scenario in which we estimate a viewing angle 2°<θ<5° and a different jet velocity for the radio and the high-energy emission regions, such that the respective Doppler factors are δr∼3 and δh.e.∼14.

Abstract Copyright:

Journal keyword(s): galaxies: active - BL Lacertae objects: individual: Mrk 421 - galaxies: jets

VizieR on-line data: <Available at CDS (J/A+A/545/A117): table2.dat fits.dat fits/*>

CDS comments: Fig.2 Components CN not in Simbad.

Simbad objects: 4

goto Full paper

goto View the reference in ADS

Number of rows : 4

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 QSO J0854+2006 BLL 08 54 48.8749311881 +20 06 30.642936668   15.91 15.43 15.56   ~ 1943 1
2 ICRF J092703.0+390220 Sy1 09 27 03.0139516273 +39 02 20.847968628   17.17 17.00 16.486   ~ 920 1
3 Mrk 421 BLL 11 04 27.3139210166 +38 12 31.798324828   13.50 12.90 8.31   ~ 2329 1
4 7C 1308+3236 BLL 13 10 28.66387 +32 20 43.7831   15.61 15.24 17.91   ~ 736 1

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2012A&A...545A.117L and select 'bookmark this link' or equivalent in the popup menu


2019.10.17-08:49:36

© Université de Strasbourg/CNRS

    • Contact