People Working for ALMA (5) Interview with an Astronomer Working at the Santiago Office of the Joint ALMA Observatory
Working in Santiago, Surrounded by Beautiful Mountains
── How long have you been in Chile?
Ishii: It has been almost two years since I was transferred to Chile in October 2016.
── Where had you been before you came here?
Ishii: I was working at the Institute of Astronomy of the University of Tokyo in Mitaka. Before that, I was working for a project at the University of Tsukuba. My first visit to Chile was 2009.
── Almost ten years have passed since your first visit to Chile.
Ishii: Right. After earning Ph.D. in Japan, I was working as a post-doctoral fellow at the University of Chile. So, this is the second time for me to live in Chile. In total, I’ve been in Chile for almost five years. It’s getting to be a quite long period.
── What do you feel about living in Chile?
Ishii: Compared to five or ten years ago, Santiago is becoming urbanized with big shopping malls and new condominiums. When I was at the University of Chile, I was renting an attic room of a house. Now, the house was replaced by a high-rise condominium.
── Snowcapped mountains look beautiful from the window of the office.
Ishii: In the morning after a rain, air is so fresh and the view of the mountains is fantastic. I was born and raised in Nagano prefecture, surrounded by mountains. Since Santiago has a similar view of mountains, I feel peaceful while looking at a beautiful view of mountains on a sunny day. When I was living in Tokyo, I sometimes felt a kind of restlessness due to lack of mountains. Some of the mountains here exceeds 4,000 m above sea level. So, it feels a little too high to me (laugh).
One day at the Santiago Office
── Previously, we interviewed Satoko Takahashi at the OSF (at 2,900) in the Atacama Desert. We heard Takahashi-san is a member of the ALMA Department of Science Operations (DSO) at the Joint ALMA Observatory (JAO), which is responsible for the operations of ALMA. Are you also a member of the DSO?
Ishii: Yes, I am also a DSO member and I also work in shifts at the OSF as Takahashi-san does. I’m working in Santiago today.
── Could you tell us about your daily schedule at the Santiago office?
Ishii: Since we are not working in shifts here, we usually work during daytime. I come to the office around 9 a.m. and start checking emails. And then, I look through the observations conducted the previous night to see if there were problems, especially in the area related to my responsibility. This is very important.
── Specifically, what is your responsibility?
Ishii: I am in charge of a software tool called Shift Log Tool. This software is designed to obtain and accumulate observation records in almost real time, while logging the details of an observation, including the project name, observation starting/ending time, the number of antennas deployed, weather conditions during the observation, and records of problems, etc. Based on these data, the tool calculates the efficiency of the observation and provides statistical values that help identify the cause of idle time as well. This tool should be working all the time since it is used as a source of making daily reports that are shared among all members of the ALMA project. So, I need to address any problems with it, if any.
── It must be an important task.
Ishii: Another task is related to the “off position”.
── What is the “off position”?
Ishii: In conducting ALMA observations, we have two types of observation methods: interferometer or single-dish observation. In either case of observations, we measure the intensity of radio emissions from a target object, but in the single-dish observation, we also receive unwanted radio emissions from the Earth’s atmosphere. So, in order to obtain an accurate measurement, we observe a point with no astronomical sources, which is called the “off position”, and measure the intensity of radio emission exclusively from the Earth’s atmosphere. And then, we calculate the intensity of radio emissions from the target object by subtracting the radio intensity of the sky from the intensity of the target object.
── I see. You need to remove unnecessary radio from the Earth’s atmosphere.
Ishi: Right. For accurate measurement of the radio intensity of the target object, we need to observe the off position. It is our responsibility to assure that the off positions are really free from radio waves from unexpected sources.
── Have you ever had a problem?
Ishii: Yes. In a recent case, we had to stop an ongoing observation when the off position came close to the zenith. Actually, ALMA is not good at observing the point directly above. This is a common issue for the telescopes that are movable both in the elevation and horizontal angles. So, if such things happen, we take measures like setting a different off position, giving a warning to the operator, or anything appropriate.
── You always need to keep your eye on what is going on.
Ishii: After finishing these tasks, we usually have a morning meeting. For example, last Friday, we had a meeting among controllers of Shift Log Tool. For the release of a new version, we held an online meeting for an hour with software engineers at the European Southern Observatory (ESO) in Germany. After the meeting, we summarized the results of discussions and updated our development schedule accordingly. For about two hours from noon to 3 p.m. excluding lunch time, I worked on the data analysis and preparation of a report for ensuring reliability of observation data.
From 3 p.m., we have a meeting connecting the Santiago office and the OSF and talk about the observations implemented the previous night, the current status of the telescope, the schedule of observations to be carried out during the night. The meeting is attended by almost all members of the DSO.
── Do you hold meetings connecting Santiago and OSF?
Ishii: Yes, we have meetings for about half an hour every day. After this meeting, I go back to my desk and prepare materials for another meeting, such as for an evaluation test of a new observation mode. Establishing new observation modes is a part of our task. If I still have time left, I work on my scientific paper until the closing time and go home.
Leveraging own strength
── Both you and Takahashi-san belong to the DSO. Do you assume responsibilities similar to hers?
Ishii: Some responsibilities are common, but we have different tasks as well. As explained earlier, I am in charge of the management of “off position” for ensuring reliability of observation data (data calibration) because I have long experience in single-dish observations. On the other hand, Takahashi-san has extensive experience in interferometer observations. So, she is in charge of a different task. Although our responsibilities are similar, but we are dealing with slightly different tasks leveraging our own strengths.
── Before deciding your tasks, is it possible to express your preference?
Ishii: Yes. We talk with our boss about our strengths and interest based on the past experiences. A final decision is made considering how well they match the need of the Joint ALMA Observatory at that point.
── I see, here at the Santiago office, astronomers are engaged in a wide variety tasks for ALMA operations, making the best use of their expertise.
Ishii: Yes, that’s what we are doing here.
── What is the difference between the tasks at the OSF and the Santiago office?
Ishii: At the telescope operating site OSF, we are mostly addressing tasks that are related directly to observations for the day and responding to problems. On the other hand, at the Santiago office, our focus is placed on the support work for daily operations, data calibration, which is important in the preparatory stage of observations, and evaluation tests of new observations modes for the future.
── So, you are conducting tasks that are difficult to carry out at the OSF.
Ishii: At the OSF, astronomers of the DSO are on duty in shifts, but when a problem arises, it’s not always the case that the person who is most familiar with the situation is there. Of course, if possible, astronomers on duty deal with things on site, but when necessary we provide support from Santiago.
── The team has a strong support system. Do you have any particular task that you are keen on?
Ishii: I’m devoted to the off position that I mentioned earlier. We often carry out observations of radio emission from carbon monoxide molecule (CO) contained in a molecular cloud, a star forming region in the universe. ALMA is an extremely high sensitivity telescope, so it sometimes catches radio emissions even at off positions, where we thought there was no radio waves from celestial bodies, but actually diffuse molecular clouds were there. Previously, we had quite a number of such cases and it had been one of the challenges to overcome. When it happens, we had to ask the proposer of the observation to make a suggestion of a different off position. And then, we needed to make another observation and check again if there is no radio emission detected. This is a considerable loss of observation time.
── You have a long waiting list of observations.
Ishii: Among proposers of ALMA observations, there are researchers who are not radio astronomers. It is difficult to ask non-radio astronomers to find an appropriate off position by themselves. So, astronomers of the Joint ALMA Observatory need to take care of them. It is our responsibility to find a clear off position. We are undertaking this task with a team of about eight people and I am in charge of the technical lead.
Toward the Goal and Beyond
── Could you explain your task in more details?
Ishii: When we search for an off position, we decide detailed parameters as to what molecules are observed, how far the location of an off position could be away from the target object, and the like. And then, we prepare observation programs to operate the telescope and make a test observation of the candidate off position. For this part of the preparation and test observations from the OSF are undertaken by other team members. Through cooperation with various people, we finally find a clean off position.
── That’s a quite detailed work.
Ishii: It was a process of trials and errors. Eventually, we provided about 80 off positions for the target objects as desired by researchers. So far, unnecessary radio emissions have not been found from these off positions. As we had such trials and errors and hardships, I am glad to see the things going well. Also, I feel it challenging and rewarding to be engaged in this work.
── Do you conduct an individual test of an off position to be matched with each observation proposal adopted by ALMA every year?
Ishii: Right. Firstly, we define test items according to the observation proposal. For example, we make a plan to search for an off position around the Orion Nebula targeting on carbon monoxide (CO). And then, we make a list of candidate off positions based on previous observation data and conduct actual tests for confirmation. As we become familiar with these procedures, we’ve learned the knack of finding good off positions efficiently. While making a catalog of good off-positions, we are making preparations for different observation proposals.
── As you mentioned earlier, I imagine it would be very difficult for a person who has no experience in radio astronomy observations to identify a good off positions by themselves.
Ishii: Usually, we make an observation to detect radio emissions from the target object. On the other hand, in the search for the off positions, the purpose is to find a point with no emissions. So, we need to switch our mindset. It may not be a glamourous task, but I believe it is an important work to support observations.
── There are many things to be done before making an observation, not just having a telescope. Do you need to conduct various tests because of ALMA, which is an extremely high-performance telescope?
Ishii: Exactly. As you said, ALMA is a highly advanced telescope and it achieves the goals of ordinary telescopes very easily. Then, researchers around the world expect more from ALMA and come up with ideas to achieve further difficult goals. These ideas drive us to develop new observation modes.
── There are new observations beyond achieving the goals.
Ishii: True. However, it is also very important for us to provide high-quality data that meets a certain level of standards. It is not sufficient that we see a possibility for success. We need to make a clear scheme with specified conditions, observation plans, and analysis procedures to produce data, which is durable for research use. All of these are our responsibility.
── We’ve learned astronomers like you are working here at the Santiago office and at the OSF while serving as a link between the development of highly advanced instruments of ALMA and scientific research.
Ishii: Thank you.
Japan Accounts for One Forth
── Now, I would like to hear about attracting aspects of working at an international research institute like ALMA, and difficulties you have.
Ishii: In terms difficulties, I had a hard time to get used to the complex environment, which is unique to ALMA, for two years since I came here. In addition to a wide variety of people coming from all over the world, ALMA has 66 antennas, various systems, and regional centers around the world. The distribution of personnel is complicated, and the systems are also complicated. It was quite difficult to get used to such environment.
── These conditions are unique to ALMA.
Ishii: You might think it would be hard to work overseas, but I have a quite number of Japanese colleagues here. Although ALMA is an international research institute, Japan makes contributions with a share equivalent to 25% not only financially but also in personnel. So, I don’t feel lonely at a foreign research institute away from Japan. I rather feel the presence of Japan that accounts for one fourth of the observatory actually. When I was a post-doctoral fellow at the University of Chile, I had a feeling of being totally in a foreign country because I was only a Japanese there. So, the environment is very different now.
── You feel like being in your home country at least in one fourth of your workplace. That’s a quite new way of thinking.
Ishii: I often hear that Japanese colleagues had a hard time establishing an organization composed of such diversified people from various nationalities at an early stage. We owe a lot what we are receiving now to those people who strived to create a comfortable work environment like this.
── It must be a good point about working here.
Ishii: True. In addition, I have many colleagues who have small kids. So, the observatory is very considerate of families that are taking care of children. This is another good point too.
── You are working with people from various countries. Do you think their workstyles are different?
Ishii: For example, since Europe is now in the vacation season, our European colleagues are on long leave. They take a time to refresh themselves during vacation, and work hard when they come back to work. They clearly separate the time for work and private time. In Japan, there is no such clear dividing line, so it’s interesting to know about different workstyles while working with colleagues from other countries.
── I heard Japanese researchers have a long vacation on New Year’s holidays, but Europeans also have Christmas holidays, right?
Ishii: Yes. So, I have an impression of Chilean or Japanese astronomers being mostly in charge of operations at the OSF during New Year’s holidays (laugh). However, there is a rule that the number of shifts of one person working at the OSF may not exceed eight times a year regardless of nationality. This means, it is just a matter of when we complete our shifts of eight times, earlier or later than others.
Aiming to Explore Various Stages of Star Formation with ALMA
── What kind of research are you conducting on top of your duties related to operations?
Ishii: My research theme is to study star formation in the Milky Way galaxy. Stars are formed in cold gas, which is observed in the millimeter/submillimeter wavelengths. So, ALMA is very suitable for observing it. Especially, I have a particular interest in the formation of massive stars. Although massive stars have a short lifespan, they emit strong ultraviolet rays, and at the end of life, they cause a supernova explosion, which has a great influence on the surroundings. However, there are still many parts that are not known in terms of how they are formed, so I am paying close attention to it. We use telescopes such as ALMA to see what environment is required for the formation of a massive star and how it affects the surroundings.
Ishii: In particular, the research of star formation covers a very wide range of phenomena, from a very large scale such as a huge molecular cloud of a scale of several hundred light years to a small scale of individual stars. So, exploring such a large scale of changes is also very interesting to me. I am trying to monitor various stages of star formation using ALMA.
── Are there any celestial bodies that you are paying particular attention to in your research of star formation?
Yes. One of them is the Orion Nebula, which was recently observed using the Nobeyama Radio Observatory’s 45-m Telescope as a part of the Star Formation Legacy Project. We have been observing a very wide area with the telescope to investigate the structure of the Orion molecular cloud in detail (Note: we published a paper about the results of this observation in 2019). I would like to explore the interesting regions with ALMA.
── I hear that the data obtained with ALMA is an order of magnitude better than previous telescopes. What is your impression about it?
Ishii: Setting aside my work of ALMA operations, my view as an observer is that ALMA not only provides us the data as we expected, but it sometimes delivers the data that exceeds our expectation. I am very surprised. In particular, ALMA is able to observe multiple types of molecular gas with a single observation. I was surprised to see how clearly ALMA revealed the distributions of different types of molecules.
── This is a final question. How do you see your future prospects?
Ishii: It’s been about two years since I came to the ALMA project, and I’m getting used to my work and the results of various efforts are coming out. So, now I have a strong desire to play a more solid role and contribute more. I don’t know where this would lead me to, but I hope what I’m doing at ALMA right now will lead to the next step. It’s nice to have a lot of work and I enjoy all of them. But, since I’m working at ALMA and handling ALMA data, I would also like to use ALMA for my research as an astronomer.
── Does that mean making an observation proposal and having your own data?
Ishii: Yes. Based on the results of observations with the Nobeyama 45-m Telescope, we made a proposal of a project for ALMA observation. It was successfully adopted and its observation was carried out. It was an observation of star-forming regions within the Galaxy. There are some unexpected outcomes that are difficult to interpret, but interesting results are emerging.
── You have to balance your work here and your scientific research.
Ishii: Right. Speaking of research, I submitted an observation proposal with the members of the international team, and fortunately it was adopted in observation Cycle 5 (FY2017). I hope that such collaboration can be further promoted.
── I am looking forward to seeing your future research results. Thank you very much.