Publications of The Korean Astronomical Society (천문학논총)

The Korean Astronomical Society (한국천문학회)
권호 표지
DOI QR코드

DOI QR Code

22 GHz MONITORING OF SGR A* DURING THE G2 PERI-CENTER PASSING WITH THE JAPANESE VLBI NETWORK

  • KAMEYA, O. (National Astronomical Observatory of Japan) ;
  • TSUBOI, M. (ISAS/JAXA) ;
  • ASAKI, Y. (ISAS/JAXA) ;
  • YONEKURA, Y. (Ibaraki Univ.) ;
  • MIYAMOTO, Y. (Univ. of Tsukuba) ;
  • KANEKO, H. (Univ. of Tsukuba) ;
  • SETA, M. (Univ. of Tsukuba) ;
  • NAKAI, N. (Univ. of Tsukuba) ;
  • MIYOSHI, M. (National Astronomical Observatory of Japan) ;
  • TAKABA, H. (Gifu Univ.) ;
  • WAKAMATSU, K. (Gifu Univ.) ;
  • FUKUZAKI, Y. (GSI) ;
  • MORIMITSU, T. (Univ. of Tokyo) ;
  • SEKIDO, M. (NICT)
  • Received : 2014.11.30
  • Accepted : 2015.06.30
  • Published : 2015.09.30
Download PDF
⟨ Previous Next ⟩

Abstract

We have been performing daily VLBI monitoring of the flux density of Sagittarius (Sgr) $A^{\ast}$ at 22 GHz from February 2013 to August 2014 using a sub-array of the Japanese VLBI Network (JVN). The purpose of this monitoring is to explore the flux density variability at daily time resolution for a period longer than one year with the G2 cloud approaching. The flux density of Sgr $A^{\ast}$ is basically stable during the observational period, though there are some small variations. The average and scattering range are consistent with the previously observed values. We have observed no strong flare of Sgr $A^{\ast}$ although it is near the expected peri-center passing.

Keywords

References

  1. Ghez, A. M., et al., 2008, Measuring Distance and Properties of the Milky Way's Central Supermassive Black Hole with Stellar Orbits, ApJ, 689, 1044 https://doi.org/10.1086/592738
  2. Gillessen, S., Eisenhauer, F., Trippe, S., Alexander, T., Genzel, R., Martins, F., & Ott, T., 2009, Monitoring Stellar Orbits Around the Massive Black Hole in the Galactic Center, ApJ, 692, 1075 https://doi.org/10.1088/0004-637X/692/2/1075
  3. Gillessen, S., Genzel, R., & Fritz, T. K et al., 2012, A gas cloud on its way towards the supermassive black hole at the Galactic Centre, Nature, 481,51 https://doi.org/10.1038/nature10652
  4. Gillessen, S., Genzel, R., & Fritz, T. K et al., 2013, Pericenter Passage of the Gas Cloud G2 in the Galactic Center, ApJ, 774, 44 https://doi.org/10.1088/0004-637X/774/1/44
  5. Kondo,T., Koyama, Y., Takeuchi, H., & Kimura, M., 2006, IVS 2006 General Meeting Proceedings, edited by Dirk Behrend and Karen Baver, NASA/CP-2006-214140, 195
  6. Narayan, R. Ozel, F. & Sironi, L., 2012, Radio Synchrotron Emission from a Bow Shock around the Gas Cloud G2 Heading toward the Galactic Center, ApJ, 757, L20 https://doi.org/10.1088/2041-8205/757/2/L20
  7. Saitoh, T. R., Makino, J., & Asaki, Y. et al., 2014, Flaring up of the Compact Cloud G2 during the Close Encounter with Sgr $A^{\ast}$, PASJ, 66, 1
  8. Tsuboi, M., Asaki, Y., & Yonekura, Y., et al., 2013a, Nondetection of Flare at 22 GHz of Sgr $A^{\ast}$ induced by the Approaching G2 Cloud in February and March 2013, ATEL, 4923, 1
  9. Tsuboi, M., Asaki, Y., & Yonekura, Y., et al., 2013b, Possible Brightening at 22 GHz of Sgr $A^{\ast}$, ATel, 5013, 1
  10. Tsuboi, M., Asaki, Y., & Yonekura, Y., et al., 2013c, Report of the Daily Monitor of Sgr $A^{\ast}$ at 22 GHz, ATel, 5184,
  11. Tsuboi, M., Asaki, Y., & Yonekura, Y., et al., 2014, Progress Report of the Monitor of Sgr $A^{\ast}$ with Japanese VLBI Network at 22 GHz until 2014/76, ATel, 6004, 1