2017A&A...597A..80H


C.D.S. - SIMBAD4 rel 1.7 - 2020.06.06CEST04:47:04

2017A&A...597A..80H - Astronomy and Astrophysics, volume 597A, 80-80 (2017/1-1)

Location of γ-ray emission and magnetic field strengths in OJ 287.

HODGSON J.A., KRICHBAUM T.P., MARSCHER A.P., JORSTAD S.G., RANI B., MARTI-VIDAL I., BACH U., SANCHEZ S., BREMER M., LINDQVIST M., UUNILA M., KALLUNKI J., VICENTE P., FUHRMANN L., ANGELAKIS E., KARAMANAVIS V., MYSERLIS I., NESTORAS I., CHIDIAC C., SIEVERS A., GURWELL M. and ZENSUS J.A.

Abstract (from CDS):

Context. The γ-ray BL Lac object OJ 287 is known to exhibit inner-parsec "jet-wobbling", high degrees of variability at all wavelengths and quasi-stationary features, including an apparent (~=100°) position-angle change in projection on the sky plane.
Aims. Sub-50 micro-arcsecond resolution 86GHz observations with the global mm-VLBI array (GMVA) supplement ongoing multi-frequency VLBI blazar monitoring at lower frequencies. Using these maps, together with cm/mm total intensity and γ-ray observations from Fermi-LAT from 2008-2014, we aim to determine the location of γ-ray emission and to explain the inner-mas structural changes.
Methods. Observations with the GMVA offer approximately double the angular resolution compared with 43GHz VLBA observations and enable us to observe above the synchrotron self-absorption peak frequency. Fermi-LAT γ-ray data were reduced and analysed. The jet was spectrally decomposed at multiple locations along the jet. From this, we could derive estimates of the magnetic field using equipartition and synchrotron self-absorption arguments. How the field decreases down the jet provided an estimate of the distance to the jet apex and an estimate of the magnetic field strength at the jet apex and in the broad line region. Combined with accurate kinematics, we attempt to locate the site of γ-ray activity, radio flares, and spectral changes.
Results. Strong γ-ray flares appeared to originate from either the so-called core region, a downstream stationary feature, or both, with γ-ray activity significantly correlated with radio flaring in the downstream quasi-stationary feature. Magnetic field estimates were determined at multiple locations along the jet, with the magnetic field found to be ≥1.6G in the core and ≤0.4G in the downstream quasi-stationary feature. We therefore found upper limits on the location of the VLBI core as ≤6.0pc from the jet apex and determined an upper limit on the magnetic field near the jet base of the order of thousands of Gauss.

Abstract Copyright: © ESO, 2017

Journal keyword(s): BL Lacertae objects: individual: OJ 287 - galaxies: active - magnetic fields - techniques: high angular resolution - techniques: interferometric - galaxies: jets

VizieR on-line data: <Available at CDS (J/A+A/597/A80): list.dat fits/*>

Status at CDS:  

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 - 2020
#notes
1 8C 0716+714 BLL 07 21 53.4484901266 +71 20 36.362058601   15.5 14.17 14.27   ~ 1127 1
2 QSO J0854+2006 BLL 08 54 48.8749311881 +20 06 30.642936668   15.91 15.43 15.56   ~ 1991 1
3 NAME BL Lac BLL 22 02 43.2913773726 +42 16 39.978417860   15.66 14.72     ~ 2002 1
4 4C 11.69 QSO 22 32 36.40890517 +11 43 50.9040717   17.75 17.33     ~ 963 2

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2017A&A...597A..80H and select 'bookmark this link' or equivalent in the popup menu


2020.06.06-04:47:04

© Université de Strasbourg/CNRS

    • Contact