Millimeter/submillimeter VLBI sciences with ALMA

Credit: ESO/O. Furtak

2021 December 20 (Mon) and 22 (Wed), online only

Scientific rationale:

In the last decade, ALMA has been improving the highest resolution up to 10 milli-arcseconds with the most-extended configuration up to Band 7. In addition, ALMA joins the GMVA and EHT collaborations to produce the first historical image of a super-massive black hole shadow in M87, which reached the highest resolution of 20 micro-arcseconds at 230 GHz.

While the VLBI mode of ALMA was open only for continuum sources at Bands 3 and 6 until Cycle 8, it is planned to open for spectral line sources from Cycle 9. Using this new capability, ALMA will be able to provide opportunities to make VLBI images for millimeter/submillimeter maser lines. Furthermore, ALMA will have a greater potential to produce high resolution continuum images for broader kinds of astronomical objects other than AGNs. Thus, it is timely to discuss possible science cases which should be done by utilizing VLBI mode of ALMA before the call for proposals of Cycle 9.

For this purpose, we will organize the ALMA workshop on millimeter/submillimeter VLBI sciences. We would like to develop discussion on science cases that can be newly achieved with VLBI at the ALMA frequency bands but not by currently available centimeter/millimeter VLBI networks.


Click the "Registration Registration" button below the title of this page to proceed to the registration form.

The deadline for talks will be December 6th, and that without talks will be December 13th.


December 20(Mon) Name Affiliation Title

13:30-13:40 Tomoya Hirota NAOJ Aim of this WS

13:40-14:20 Hiroshi Nagai NAOJ VLBI capability in Cycle 9*

14:20-15:00 Hiroshi Imai Kagoshima U. Circumstellar Masers Observed in ALMA-VLBI

15:00-15:10 Break

15:10-15:50 Tomoya Hirota NAOJ Possibilities of star-formation studies with the millimeter/submillimeter masers*

15:50-16:30 Hiroyuki Nakanishi Kagoshima U. Studies on Galactic structures with the ALMA long-baselines*

16:30-17:00(Max) Discussion

December 22(Wed) Name Affiliation Title

13:30-14:10 Motoki Kino Kogakuin U./NAOJ Unveiling the jet base structure of Cygnus A

14:10-14:50 Shoko Koyama Niigata U./ASIAA Resolving the jet collimation region in TeV blazar Mrk 501

14:50-15:30 Kohei Kurahara NAOJ Probing early jet-ISM interaction with time variability

15:30-15:40 Break

15:40-16:20 Yoshiaki Hagiwara Toyo U. Sub-millimeter VLBI observations of extragalactic Maser (TBD)

16:20-17:00 Satoko Sawada-Satoh Yamaguchi U. Mass accretion of AGNs at pc/sub-pc scales*

17:00-17:30(Max) Discussion

* Japanese titles are translated into English by the SOC.

30 minutes talk and 10 minutes discussion

Talks will be in Japanese, while English is also accepted. English presentation files are recommended.

The workshop will be held via zoom. The zoom link information will be announced only to the registered participants.

The workshop will be recorded for references. Presentation files will also be collected. Both files will be shared only by the actual attendees in the workshop session via the password-protected cloud server.


Tomoya HIROTA (NAOJ, Mizusawa, co-chair)

Hiroshi NAGAI (NAOJ, ALMA, co-chair)

Hiroshi IMAI (Kagoshima University)

Shoko KOYAMA (Niigata University)

Kazuhito MOTOGI (Yamaguchi University)

Hiroyuki NAKANISHI (Kagoshima University)