Hostname: page-component-848d4c4894-2pzkn Total loading time: 0 Render date: 2024-05-27T18:02:54.769Z Has data issue: false hasContentIssue false

The origin of the Perseus-arm gap revealed with VLBI astrometry

Published online by Cambridge University Press:  07 February 2024

Nobuyuki Sakai*
Affiliation:
National Astronomical Research Institute of Thailand (Public Organization).
Hiroyuki Nakanishi
Affiliation:
Graduate School of Science and Engineering, Kagoshima University
Kohei Kurahara
Affiliation:
National Astronomical Observatory of Japan, Oshu-shi, Iwate 023-0861, Japan
Daisuke Sakai
Affiliation:
National Astronomical Observatory of Japan, Oshu-shi, Iwate 023-0861, Japan The Iwate Nippo Co., Ltd.
Kazuya Hachisuka
Affiliation:
National Astronomical Observatory of Japan, Oshu-shi, Iwate 023-0861, Japan
Jeong-Sook Kim
Affiliation:
Ulsan National Institute of Science and Technology / Chungbuk National University
Osamu Kameya
Affiliation:
National Astronomical Observatory of Japan, Oshu-shi, Iwate 023-0861, Japan Oshu Space & Astronomy Museum

Abstract

The Perseus arm has a gap in Galactic longitudes (l) between 50° and 80° where the arm has little star formation activity. To understand the gap, we conducted VERA (VLBI Exploration of Radio Astrometry) astrometry and analyzed archival H <SC>I</SC> data. We report on parallax and proper motion results from four star-forming regions, of which G050.28–00.39 and G070.33+01.59 are associated with the gap. Perseus-arm sources G049.41+00.32 and G050.28–00.39 lag relative to a Galactic rotation by 77 ± 17 km s-1 and 31 ± 10 km s-1, respectively. The noncircular motion of G049.41+00.32 cannot be explained by the gravitational potential of the arm. We discovered rectangular holes with integrated brightness temperatures less than 30 K arcdeg in l vs. VLSR of the H <SC>I</SC> data. Also, we found extended H <SC>I</SC> emission on one side of the Galactic plane when integrating the H <SC>I</SC> data over the velocity range covering the hole. G049.41+00.32 and G050.28–00.39 are moving toward the emission. The Galactic H <SC>I</SC> disk at the same velocity range showed an arc structure, indicating that the disk was pushed from the lower side of the disk. All the observational results might be explained by a cloud collision with the Galactic disk.

Type
Contributed Paper
Copyright
© The Author(s), 2024. Published by Cambridge University Press on behalf of International Astronomical Union

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Anglada, G., Estalella, R., Pastor, J., Rodriguez, L. F., & Haschick, A. D. 1996, ApJ, 463, 205 CrossRefGoogle Scholar
Bailer-Jones, C. A. L. 2015, PASP, 127, 994 CrossRefGoogle Scholar
Churchwell, E., Babler, B. L., Maede, M. R., et al. 2009, PASP, 121, 213 CrossRefGoogle Scholar
Dame, T. M, Hartmann, D., & Thaddeus, P. 2001, ApJ, 547, 792 CrossRefGoogle Scholar
Drimmel, R. 2000, A&A, 358, L13 Google Scholar
Georgelin, Y.-M., & Georgelin, Y.-P. 1976, A&A, 49, 57 Google Scholar
Kalberla, P. M. W., Burton, W. B., Hartmann, D., Arnal, E. M., Bajaja, E., Morras, R., & Pöppel, W. G. L. 2005, A&A, 440, 775 Google Scholar
Kamezaki, T., Nakagawa, A., Omodaka, T., et al. 2012, PASJ, 64, 7 CrossRefGoogle Scholar
Kurayama, T., Nakagawa, A., Sawada-Satoh, S., Sato, K., Honma, M., Sunada, K., Hirota, T., & Imai, H. 2011, PASJ, 63, 513 CrossRefGoogle Scholar
Miville-Deschênes, M. -A., Murray, N., & Lee, E. J. 2017, ApJ, 834, 57 CrossRefGoogle Scholar
Oyama, T., Kono, Y., Suzuki, S., et al. 2016, PASJ, 68, 105 CrossRefGoogle Scholar
Reid, M. J., Dame, T. M., Menten, K. M., & Brunthaler, A. 2016, ApJ, 823, 77 CrossRefGoogle Scholar
Reid, M. J., et al. 2019, ApJ, 885, 131 CrossRefGoogle Scholar
Russeil, D. 2003, A&A, 397, 133 Google Scholar
Sakai, N., Reid, M. J., Menten, K. M., Brunthaler, A., Dame, T. 2019, ApJ, 876, 30 CrossRefGoogle Scholar
Sakai, N., Nakanishi, H., Kurahara, K., Sakai, D., Hachisuka, K., Kim, J. -S., & Kameya, O. 2022, PASJ, 74, 209 CrossRefGoogle Scholar
Shirley, Y. L., Ellsworth-Bowers, T. P., Svoboda, B., et al. 2013, ApJS, 209, 2 CrossRefGoogle Scholar
Svoboda, B. E., et al. 2016, ApJ, 822, 59 CrossRefGoogle Scholar
Urquhart, J. S., et al. 2007, A&A, 474, 891 Google Scholar
Urquhart, J. S., Figura, C. C., Moore, T. J., et al. 2014, MNRAS, 437, 1791 CrossRefGoogle Scholar
van Moorsel, G., Kemball, A., & Greisen, E. 1996, in ASP Conf. Ser., 101, Astronomical Data Analysis Software and Systems V, ed. Jacoby, G. H. & Barnes, J. (San Francisco: ASP), 37Google Scholar
Xu, Y., Hao, C. J., Liu, D. J., et al. 2023, ApJ, 947, 54 CrossRefGoogle Scholar
Yang, J., Jiang, Z., Wang, M., Ju, B., & Wang, H. 2002, ApJS, 141, 157 CrossRefGoogle Scholar
Zhang, B., Reid, M. J., Menten, K. M., et al. 2013, ApJ, 775, 79 CrossRefGoogle Scholar