Meeting Report: High-Resolution X-ray Spectroscopy

H. Moritz Günther, David Huenemoerder

This Summer’s Chandra workshop was held at MIT on Aug 1–3, with a focus on High Resolution X-ray Spectroscopy (HRXS). In spite of the MIT policy of "no food or drink in classrooms" (i.e., no coffee), most attendees managed to stay awake most of the time, due to the engaging subject matter. We encourage you to verify this for yourself, as all talks were recorded and are available at the conference website.

The workshop covered a broad range of topics, including the interstellar and circumgalactic media, stars, active galactic nuclei, X-ray binaries, cataclysmic variables, supernova remnants, and laboratory astrophysics. Talks featured high-resolution spectra not just from Chandra HETG and LETG, but also XMM-Newton RGS and Hitomi as well as anticipated insights from XRISM and to-be-proposed probe-class missions Arcus and LEM. At least one talk even went as far back as to discuss results from the Einstein crystal spectrometer!

At the last coffee break of the meeting we took the conference photo shown below. The diverse age range of attendees attests to vitality in the field: there were both veteran spectroscopists as well as junior researchers who will carry on with the new and planned missions.

Approximately forty people stand in two long rows at the end of a wide room. They have name tags hanging off lanyards around their necks and are dressed nicely.

In-person participants of the HRXS Workshop pose for a group photo in Marlar during the final afternoon coffee break.

Some things we had in this workshop

Brain-storming the "legacy of Chandra"

On the second day of the workshop we had "brain-storming" sessions in small groups, focused on Diffuse matter and Galaxies, Stars, AGN, and Atomic Data. These sessions were open-ended discussion of needs, priorities (e.g. "What would you do with 5 Ms of Chandra data?"), or issues across a number of areas, much of it summarized on the last day. Some main themes are:

The last two points are suggestions to discuss for the Chandra director!

Some things we did not have at this workshop

The future

Looking to the future, we had proponents of the upcoming missions (or concepts) present their visions for XRISM, Athena, LEM, Arcus, and HUBS. This provided much interest and discussion on instrumental capabilities desired, the importance of different scientific programs, and the realities of logistical constraints (time, budget, politics).

Meeting format, organization, and implementation

"This is the first Zoom meeting I actually enjoyed." — Ehud Behar

We decided early on that this meeting should be held in hybrid mode. We want to discuss here what exactly we did to make the meeting a hybrid success, because hybrid meetings are still relatively new to the astronomical community and we are all still figuring out how to do that right.

On the one hand, many people like the in-person interactions, the informal discussions during coffee or lunch that could not be pre-planned, and the meeting of old friends that are enabled by physical presence at meetings. On the other hand, remote meetings have many undeniable advantages, too. They allow people to attend who cannot travel to Cambridge, MA (or wherever the meeting is being held) because of visa issues, because they care for elderly family members or children, because they don’t have the travel funding, because they don’t want to spend many hours on international flights for just three days of meeting, or because they want to reduce the CO2 footprint of astronomy (online meetings emit about three to four orders of magnitude less CO2 per average participant than in-person meetings). We had about 65 in-person registrations and 150 remote registrations at this meeting; a look at the map embedded below shows that the remote option made this meeting accessible to large parts of the world that otherwise (based on experience in previous workshops) would not have traveled to Cambridge.

Participation map with location pins

Blue: participant registered in-person, red: remote. Locations are taken from participants' affiliation or top level domain of their email address and randomized by +/- 1 degree to reduce overlap of markers.

Neither in-person nor virtual participants attended all sessions; a typical session had about 30–40 people in the audience and 30–40 people on zoom.

The SOC and LOC worked together to have good interactions between in-person and remote participants. Instead of paper posters, we had 3-min flash talks fully integrated into the program; we had both contributed and invited talks in-person and remote; and we organized a discussion section on the "Legacy of Chandra" in a manner that included both sets of attendees. For this section, attendees suggested the topics to discuss and we set up three separate zoom rooms with A/V equipment; remote attendees reported that they felt fully integrated in the discussion. All of this was possible because we (the LOC) chose to use rooms at MIT, where many of us work and where we know the rooms and equipment well.

A woman standing next to a podium addresses a large group of seated people. The image is viewed from the speaker’s left, looking out onto the crowd from the edge of the room. The room itself is wide but shallow, and everyone is seated at long tables with built-in chairs. On the right are the glow from three projection screens; while they are out of frame, three projectors are seen mounted to the ceiling.

Ioanna Psaradaki speaking on the first morning of the conference.

Also, we decided to run all A/V equipment ourselves and not pay professional A/V services. It required several practice sessions to figure out the setup, but it allowed us to keep registration fees very low—also an important consideration to make the workshop accessible to all interested researchers.

We thank the SOC and LOC for an efficiently run and productive meeting. And we thank the MIT/MKI administrative staff for their fantastic help with setup and cleanup every day of the meeting.

Main regrets

Although the workshop was otherwise a success, we do have one regret. We had our lunch and coffee breaks in MIT’s Marlar lounge. In there—just a few feet away from the cookies and on display in a glass case—sits an engineering model of ACIS. Some participants might have seen it, but maybe we should have pointed it out to everyone? Consider it a treasure hunt…

Eight people sit loosely around two low-lying tables. Several laptops and an OWL video conference unit are seen. The group is focused on one participant currently talking. About ten feet behind this group is a wall, and, in that wall is a glass display case. Several electronic devices are displayed prominently in that case, along with old pictures.

A breakout session in the Future of Chandra panel sits in discussion in Marlar. Behind them is a glass case that went unremarked by the conference organizers.