DOI QR코드

DOI QR Code

MEASURING THE CORE SHIFT EFFECT IN AGN JETS WITH THE EXTENDED KOREAN VLBI NETWORK

JUNG, TAEHYUN;DODSON, RICHARD;HAN, SEOG-TAE;RIOJA, MARIA J.;BYUN, DO-YOUNG;HONMA, MAREKI;STEVENS, JAMIE;VICENTE, PABLO DE;SOHN, BONG WON

  • Received : 2015.09.02
  • Accepted : 2015.10.15
  • Published : 2015.10.31

Abstract

We present our efforts for extending the simultaneous multi-frequency receiver system of the Korean Very Long Baseline Interferometry (VLBI) Network (KVN) to global baselines in order to measure the frequency-dependent position shifts in Active Galactic Nuclei (AGN) jets, the so called core shift effect, with an unprecedented accuracy (a few micro-arcseconds). Millimeter VLBI observations with simultaneous multi-frequency receiver systems, like those of the KVN, enable us to explore the innermost regions of AGN and high precision astrometry. Such a system is capable of locating the frequency dependent opacity changes accurately. We have conducted the feasibility test-observations with the interested partners by implementing the KVN-compatible systems. Here we describe the science case for measuring the core shift effect in the AGN jet and report progress and future plans on extending the simultaneous multi-frequency system to global baselines.

Keywords

techniques: interferometeric;astrometry;high angular resolution;radio continuum: active galactic nuclei

References

  1. Reid, M. J., & Honma, M. 2014, Microarcsecond Radio Astrometry, ARAA, 52, 339 https://doi.org/10.1146/annurev-astro-081913-040006
  2. Williams, W., Nixon, D., Reilly, H., et al. 1979, A Prototype DSN XS Band Feed: DSS 13 Application Status (Third Report), DSN Progress Report 42, 51
  3. Zorzi, P., Granet, C., Colleoni, F., et al. 2012, Construction and Measurement of a 31.3–45 GHz Optimized Splineprofile Horn with Corrugations, J. of Infrared, Millimeter, and Terahertz Waves, 33, 17 https://doi.org/10.1007/s10762-011-9834-1
  4. Middelberg, E., Roy, A. L, Walker, R. C., & Falcke, H. 2005, VLBI Observations of Weak Sources Using Fast Frequency Switching, A&A, 433, 897
  5. Napier, P. J. 1995, VLBA Design, eds. Zensus, J. A., Diamond, P. J., & Napier, P. J., Very Long Baseline Interferometry and the VLBA, ASP, 82, 59
  6. Porcas, R. W., & Rioja, M. J. 2002, VLBI Phase-Reference Investigations at 86 GHz, eds. Ros, E., Porcas, R. W., Lobanov, A. P., & Zensus, J. A., Proceedings of the 6th EVN Symposium, 65
  7. Rioja, M. J., Dodson, R., Jung, T., & Sohn, B. W. 2015, The Power of Simultaneous Multi-Frequency Observations for mm-VLBI: Astrometry up to 130 GHz with the KVN, AJ, submitted
  8. Rioja, M., & Dodson, R. 2011, High-Precision Astrometric Millimeter Very Long Baseline Interferometry Using a New Method for Atmospheric Calibration, AJ, 141, 114 https://doi.org/10.1088/0004-6256/141/4/114
  9. Rioja, M., Dodson, R., Malarecki, J., & Asaki, Y. 2011, Exploration of Source Frequency Phase Referencing Techniques for Astrometry and Observations of Weak Sources with High Frequency Space Very Long Baseline Interferometry, AJ, 142, 157 https://doi.org/10.1088/0004-6256/142/5/157
  10. Rioja, M. J., Dodson, R., Jung, T., et al. 2014, Verification of the Astrometric Performance of the Korean VLBI Network, Using Comparative SFPR Studies with the VLBA at 14/7 mm, AJ, 148, 84 https://doi.org/10.1088/0004-6256/148/5/84
  11. Sokolovsky, K. V., Kovalev, Y. Y., Pushkarev, A. B., & Lobanov, A. P. 2011, A VLBA Survey of the Core Shift Effect in AGN Jets: I. Evidence of Dominating Synchrotron Opacity. A&A, 532, A38
  12. Hovatta, T., Aller, M. F., Aller, H. D., et al. 2014, MOJAVE: Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments. XI. Spectral Distributions, AJ, 147, 143 https://doi.org/10.1088/0004-6256/147/6/143
  13. Jung, T. 2011, A Study of KVN Multi-Frequency Phase Referencing, PhD dissertation, University of Science and Technology, Korea
  14. Jung, T., Sohn, B. W., Kobayashi, H., et al. 2011, First Simultaneous Dual-Frequency Phase Referencing VLBI Observation with VERA, PASJ, 63, 375 https://doi.org/10.1093/pasj/63.2.375
  15. Kim, H.-G., Han, S.-T., Sohn, B. W., et al. 2004, Construction of the Korean VLBI Network (KVN), eds. Bachiller, R., Colomer, F., Desmurs, J.-F., & de Vicente, P., European VLBI Network on New Developments in VLBI Science and Technology, 281
  16. López-Pérez, J. A., Tercero, F., Serna, J. M., & LópezFernández, J. A. 2012, A Tri-band Cryogenic Receiver for the RAEGE Project Antennas, eds. Behrend, D., & Baver, K. D., Seventh General Meeting (GM2012) of the International VLBI Service for Geodesy and Astrometry (IVS), 66
  17. Kovalev, Y. Y., Lobanov, A. P., Pushkarev, A. B., & Zensus, J. A. 2008, Opacity in Compact Extragalactic Radio Sources and its Effect on Astrophysical and Astrometric Studies, A&A, 483, 759
  18. Krichbaum, T. P., Roy, A., Lu, R.-S., et al. 2014, Millimiter VLBI observations: Black Hole Physics and the Origin of Jets, Proceedings of the 12th European VLBI Network Symposium and Users Meeting (EVN 2014), 13
  19. Lee, S.-S., Petrov, L., Byun, D.-Y., et al. 2014, Early Science with the Korean VLBI Network: Evaluation of System Performance, AJ, 147, 77 https://doi.org/10.1088/0004-6256/147/4/77
  20. Matthews, L., & Crew, G. 2015, Summary of the First ALMA Phasing Project (APP) Commissioning and Science Verification Mission, Tech. Rept.
  21. Bourda, G., Charlot, P., & Le Campion, J.-F. 2008, Astrometric Suitability of Optically-Bright ICRF Sources for the Alignment with the Future Gaia Celestial Reference Frame, A&A, 490, 403
  22. Chi, S., Barthel, P. D., & Garrett, M. A. 2013, Deep, Wide-field, Global VLBI Observations of the Hubble Deep Field North (HDF-N) and Flanking Fields (HFF), A&A, 550, A68
  23. Dodson, R., & Rioja, M. J. 2009, VLBA Scientific Memorandum n. 31: Astrometric Calibration of Mm-VLBI using “Source/Frequency Phase Referenced” Observations, Tech. Rept. NRAO.
  24. Doeleman, S. S., Weintroub, J., Rogers, A. E. E., et al. 2008, Event-Horizon-Scale Structure in the Supermassive Black Hole Candidate at the Galactic Centre, Nature, 455, 78 https://doi.org/10.1038/nature07245
  25. Hada, K., Doi, A., Kino, M., et al. 2011, An Origin of the Radio Jet in M87 at the Location of the Central Black Hole, Nature, 477, 185 https://doi.org/10.1038/nature10387
  26. Fomalont, E., Impellizzeri, V., & Wilson, C. 2014, Technical Description and Implementation of Band to Band Phase Transfer, Tech. Rept. NRAO.
  27. Garrett, M. A. 2005, Deep Field Surveys - A Radio View, eds. Gurvits, L. I., Frey, S., & Rawlings, S., EAS Publications Series, 15, 73
  28. Goldsmith, P. F. 1998, Quasioptical Systems: Gaussian Beam Quasioptical Propagation and Applications (New York: IEEE press)
  29. Han, S.-T., Lee, J.-W., Kang, J., et al. 2008, Millimeter-Wave Receiver Optics for Korean VLBI Network, Int. J. of Infrared and Millimeter Waves, 29, 69 https://doi.org/10.1007/s10762-007-9296-7
  30. Han, S.-T., Lee, J.-W., Kang, J., et al. 2013, Korean VLBI Network Receiver Optics for Simultaneous Multi-frequency Observation: Evaluation, PASP, 125, 539 https://doi.org/10.1086/671125
  31. Blandford, R. D., & Königl, A. 1979, Relativistic Jets as Compact Radio Sources, ApJ, 232, 34 https://doi.org/10.1086/157262

Cited by

  1. The Science Case for Simultaneous mm-Wavelength Receivers in Radio Astronomy 2017, https://doi.org/10.1016/j.newar.2017.09.003
  2. Millimeter VLBI observations of Sgr A* with KaVA and KVN vol.11, pp.S322, 2016, https://doi.org/10.1017/S1743921316012497

Acknowledgement

Grant : 활동성은하핵 코어이동 현상연구