Chandra Frontiers in Time-Domain Science

Rodolfo Montez Jr.

This fall the Chandra X-ray Center (CXC) held its annual science workshop on the topic of time-sensitive observations of astrophysical phenomena. The annual science workshop, organized by the Chandra Director’s Office (CDO) and a Scientific Organizing Committee, was entitled: Chandra Frontiers in Time-Domain Science1. Time-domain and time-sensitive science has always been a hallmark of Chandra science and, as new and existing facilities expand our attention on the time-domain sky, the demand for time-sensitive observations with Chandra will only increase.

The workshop featured over 100 speakers (36 invited speakers and panelists and over 70 contributed and lightning talks) over 20 science sessions and 3 panel discussions spread throughout the month of October 2020 (see schedule). Each session lasted about an hour and a half and had an average attendance of 60. The talks were all given remotely2 in 23 sessions on the popular Zoom video conferencing platform. As a result of the virtual format, all of the sessions were recorded and are available for viewing on our YouTube account. A playlist of the sessions is available here.

From the first sessions on Tidal Disruption Events and Transients on October 7th to the closing Summary by Jon Miller on October 30, the sessions were jam packed with exciting science and the collection of videos provide a trove of knowledge for novice and experienced scientists interested in the subject of time-domain science. The talks touched on numerous aspects of X-ray, multiwavelength, and multimessenger observations. Indeed, the importance of multiwavelength campaigns was a common theme through most of the workshop. This theme was explored in greater depth with the three synergies sessions (one panel discussion and two speaker sessions [Synergies I, Synergies II]), the Coordination & Communication panel discussion, and the Multi-Messenger panel discussion and speaker session. Coordinating multiwavelength observations is a major task and the Coordination & Communication panel discussion also offered a wide ranging perspective for coordination amongst satellite and ground-based observatories as well as the mission planner’s perspective.

In his summary talk, Jon Miller (University of Michigan) expanded on the mission planner’s perspective with an A-Z discussion of TOO and DDT observations as well as the ever-evolving spacecraft constraints and efforts to mitigate them. Miller also provided a thoughtful acknowledgement of out-going Chandra Director Belinda Wilkes and considered the decades in X-ray flux enabled by Chandra. Lastly, Miller concluded the summary with a look to the future and left us with a series of thought-provoking questions:

Altogether, the speakers at the workshop vividly painted the landscape of Chandra’s impact on time-domain science and identified how we might optimize Chandra’s capacity for further impact on time-domain science in the future. The CDO will carry forward the ideas raised during the workshop and construct a working group that will develop these ideas to form actionable recommendations for the CXC team. If you are interested in providing feedback, we encourage you to send us an email with your thoughts:

1. It became immediately clear that “time-domain” science has as many definitions as “soft” and “hard” amongst the community of X-ray astronomers.
2. Our original intention to host an in-person workshop at the CXC/CfA in early August, however, it became clear in April that travel limitations would persist and an adjustment was needed.