J/A+A/575/A55 Radio jet emission from GeV-emitting NLSy1 (Angelakis+, 2015)
Radio jet emission from GeV-emitting Narrow-Line Seyfert 1 galaxies.
Angelakis E., Fuhrmann L., Marchili N., Foschini L., Myserlis I.,
Karamanavis V., Komossa S., Blinov D., Krichbaum T.P., Sievers A.,
Ungerechts H., Zensus J.A.
<Astron. Astrophys. 575, A55 (2015)>
=2015A&A...575A..55A 2015A&A...575A..55A
ADC_Keywords: Active gal. nuclei ; Galaxies, radio ; Galaxies, Seyfert ;
Radio continuum ; Radio sources
Keywords: galaxies: active - gamma rays: galaxies - galaxies: jets -
galaxies: Seyfert - radio continuum: galaxies
Abstract:
With the current study we aim at gaining understanding on the
properties of radio emission and the assumed jet from four radio loud
and γ-ray loud Narrow Line Seyfert 1 galaxies i.e. Seyfert 1
galaxies with emission lines at the low-end of the FWHM distribution.
The ultimate goal is twofold; first, the investigation whether a
relativistic jet is operating at the source giving out the radio
output observed and second, the quantification of the jet
characteristics in order to understand possible similarities and
differences with the jets found in typical blazars. The current study
relies on the most systematic monitoring of radio loud and γ-ray
detected Narrow Line Seyfert 1 galaxies in the cm and mm radio bands
conducted with the Effelsberg 100-m and IRAM 30-m telescopes. It
covers the longest time baselines and the most radio frequencies, to
date. This dataset of multi- wavelength, long-term radio light curves
is analysed from a number of perspectives. A novel algorithm is
introduced in order to extract sensible variability parameters (mainly
amplitudes and timescales) which are then used for the computation of
variability brightness temperatures and the corresponding Doppler
factors. The jet powers are computed from the light curves to estimate
the energy output and compare it with typical blazars. The dynamics of
radio Spectra Energy Distributions are examined for understanding the
mechanism causing the variability. The length of the available light
curves for 3 of the 4 sources in the sample allowed a firm
understanding of the general behaviour of the sources. They all
display intensive variability which seems to be happening at a pace
rather faster than what is generally seen in blazars. The flaring
events become progressively more prominent as the frequency increases
and show intensive spectral evolution indicative of shock evolution.
The variability brightness temperatures and the associated Doppler
factors are rather moderate implying a mildly relativistic jet. The
computed jet powers show very energetic flows. The radio polarisation
in one case, clearly implies the presence of a quiescent jet
underlying recursive flaring activity. Finally, in one case, the
sudden disappearance of a γ-ray flare below some critical
frequency in our band, urges for further investigation of the possible
mechanism causing the evolution of broadband events. Despite the
generally lower flux densities the sources appear to show all typical
characteristics seen in blazars powered by relativistic jets.
Intensive variability, spectral evolution across the different bands
following evolutionary paths explained by traveling shocks, Doppler
factors indicating mildly relativistic speeds.
Description:
The radio light curves shown in Figures 2 and 3 in tabular form.
Objects:
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RA (2000) DE Designation(s) (files)
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03 24 41.16 +34 10 45.9 QSO J0324+3410 = B2 0321+33 B (j0324p34.dat)
08 49 57.98 +51 08 29.0 QSO J0849+5108 = SBSS 0846+513 (j0849p51.dat)
09 48 57.32 +00 22 25.6 QSO J0948+0022 = PMN J0948+0022 (j0948p00.dat)
15 05 06.48 +03 26 30.8 QSO J1505+0326 = PKS 1502+036 (j1505p03.dat)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
j0324p34.dat 32 309 The radio light curves of J0324+3410
j0849p51.dat 32 68 The radio light curves of J0849+5108
j0948p00.dat 32 445 The radio light curves of J0948+0022
j1505p03.dat 32 246 The radio light curves of J1505+0326
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Byte-by-byte Description of file: j*.dat
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Bytes Format Units Label Explanations
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1- 6 F6.2 GHz Freq Observing Frequency (1)
9- 17 F9.3 d MJD Modified Julian Date
20- 25 F6.3 Jy S Flux density
28- 32 F5.3 Jy e_S The error in the Flux Density
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Note (1): Observed frequencies are 2.64, 4.85, 8.35, 10.45, 14.60, 23.05,
32.00 and 43.05GHz for all the sources, plus 86.24 and 142.33GHZ for
sources J0324+3410 and J0948+0022.
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Acknowledgements:
Emmanouil Angelakis, eangelakis(at)mpifr-bonn.mpg.de
(End) Patricia Vannier [CDS] 12-Dec-2014