J/A+A/680/L3 rPICARD input files (Kim+, 2023)
First GMVA observations with the upgraded NOEMA facility:
VLBI imaging of BL Lacertae in a flaring state.
Kim D.-W., Janssen M., Krichbaum T.P., Boccardi B., MacDonald N.R., Ros E.,
Lobanov A.P., Zensus J.A.
<Astron. Astrophys. 680, L3 (2023)>
=2023A&A...680L...3K 2023A&A...680L...3K
ADC_Keywords: Models
Keywords: BL Lacertae objects: individual - BL Lac -
techniques: interferometric - radio continuum: galaxies -
galaxies: active - galaxies: jets - methods: observational
Abstract:
We analyze a single-epoch Global mm-VLBI Array (GMVA) observation of
the blazar BL Lacertae (BL Lac) at 86GHz from April 2021. The
participation of the upgraded, phased Northern Extended Millimetre
Array (NOEMA) adds additional sensitivity to the GMVA, which has
facilitated the imaging of BL Lac during an unprecedentedly strong
γ-ray flare. We aim to explore the nature of the inner subparsec
jet of BL Lac and the impact of the NOEMA participation in the
observation. For the data reduction, we employed two advanced
automatic pipelines: rPICARD for the flux density calibration as well
as the model-agnostic signal stabilization and GPCAL for the antenna
leakage calibration. The conventional hybrid imaging (CLEAN +
amplitude and phase self-calibration) was applied to the calibrated
visibilities to generate final VLBI images. We performed a ridge-line
analysis and Gaussian model-fits on the final jet image to derive the
jet parameters. In our data, the presence of NOEMA improves the image
sensitivity by a factor of 2.5. The jet shows a clear wiggling
structure within 0.4mas from the core. Our ridge-line analysis
suggests the presence of a helical jet structure (i.e., a sinusoidal
pattern). Six circular Gaussian components were fitted to the inner
jet region. We estimated an apparent brightness temperature of
∼3x1012K in the two innermost components. They are likely to
be highly boosted by relativistic beaming effect. We find four
significant polarized knots in the jet. Interestingly, two of them are
located in the core region. Finally, we suggest a number of physical
scenarios to interpret our results.
Description:
Input files for Appendix A.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
array.inp 98 71 Array input file
array_finetune.inp 202 409 Array finetune input file
constants.inp 99 389 Constants input file
flagging.inp 99 106 Flaging input file
observation1strun.inp 99 69 Observation 1st run input file
observation2ndrun.inp 99 69 Observation 2nd run input file
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Acknowledgements:
Daewon Kim, dwkimastro(at)gmail.com
(End) Patricia Vannier [CDS] 20-Nov-2023