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J/A+A/597/A80      GMVA 86GHz images of OJ 287                  (Hodgson+, 2017)

Location of gamma-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., S.Sanchez, Bremer M., Lindqvist M., Uunila M., Kallunki J., Vicente P., Angelakis E., Karamanavis V., Myserlis I., Nestoras I., Sievers A., Gurwell M., Zensus J.A. <Astron. Astrophys. 597, A80 (2017)> =2017A&A...597A..80H (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Gamma rays Keywords: BL Lacertae objects: individual: OJ 287 - galaxies: active - magnetic fields - techniques: high angular resolution - techniques: interferometric - galaxies: jets Abstract: The gamma-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. Sub-50 micro-arcsecond resolution 86GHz observations with the global mm-VLBI array (GMVA) supplement ongoing multifrequency VLBI blazar monitoring at lower frequencies. Using these maps, together with cm/mm total intensity and gamma-ray observations from Fermi/LAT from 2008-2014, we aim to determine the location of gamma-ray emission and to explain the inner-mas structural changes. Observations with the GMVA offset approximately double the angular resolution compared with 43GHz VLBA observations and enable us to observe above the synchrotron self-absorption peak frequency. Fermi-LAT gamma-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 gamma-ray activity, radio flares, and spectral changes. Description: The GMVA combines the eight 3mm receiver equipped stations of the VLBA and up to six European observatories, including Elsberg, Onsala, Metsahovi, Pico Veleta, Plateau de Bure, and since 2012, Yebes. Data were recorded at 512 Mbit/s, with eight 8MHz channels, in dual polarisation. Onsala and Yebes observed in left circular polarisation (LCP) only. For these stations, LCP was assumed to be equal to RCP and hence Stokes I. Scans of approximately 7 minutes every 15 minutes were recorded with pointing and calibration performed on European stations in the gaps between scans. Objects: ------------------------------------------------------- RA (2000) DE Designation(s) ------------------------------------------------------- 08 54 48.87 +20 06 30.6 OJ 287 = QSO J0854+2006 ------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 112 7 List of fits images fits/* 0 7 Individual fits images
Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000) 10- 18 F9.5 deg DEdeg Declination of center (J2000) 20- 23 I4 --- Nx Number of pixels along X-axis 25- 28 I4 --- Ny Number of pixels along Y-axis 30- 39 A10 "date" Obs.Date Observation date 41- 47 F7.4 GHz Freq [86.2349/86.2429] Observed frequency 49- 53 I5 Kibyte size Size of FITS file 55- 77 A23 --- FileName Name of FITS file, in subdirectory fits 79-112 A34 --- Title Title of the FITS file
Acknowledgements: Jeffrey Hodgson, jhodgson(at)
(End) Patricia Vannier [CDS] 05-Jan-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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