January 4, 2026 9 am – 5 pm AAS 247

Description

The RMDC26 AAS Workshop was a hands-on, full-day session designed to help participants—from newcomers to seasoned microlensers—get set up and productive with the Roman Research Nexus and the core open-source tools used in the Roman Microlensing Data Challenge. The workshop covered Nexus access and environment setup, essential microlensing concepts and modeling workflows, single- and binary-lens fitting, and organizing, validating, and packaging results for submission with microlens-submit. The day concluded with an information session and Q&A covering timelines, tiers, data access, evaluation, and support throughout the challenge.

Workshop Requirements

  • A laptop with a functioning web browser (optionally, VS Code and Slack installed).
  • Ideally, some Python experience.
  • An intention to participate in the Roman Microlensing Data Challenge 2026 or membership on a registered team.
  • Microlensing-specific knowledge or experience is not necessary.

Itinerary

Morning

9:00–10:30 Nexus help
10:30–11:00 Break
11:00–12:30 Single lenses and pipelines
12:30–1:30 Lunch

Afternoon

1:30–3:00 Binary lenses
3:00–3:30 Break
3:30–onward Data Challenge Q&A

Session Outlines

A. Introduction to the Nexus

In this session, you will learn how to access the Nexus, create Nexus accounts, activate kernels, install packages, access data, create your submission, and get other technical help.

In this session we will be covering:

  • Creating Nexus accounts
  • How to access the Nexus
  • Nexus notebook content:
    • Creating Teams
    • Microlensing open source software
    • Accessing data and creating data challenge submissions
  • Installing packages and other technical help
  • Using the Nexus with VSCode

For discussion, information, troubleshooting, and updates about the Nexus, see the #nexus channel and the channel canvas.

2. Single Lenses and Pipelines

In this session, we will learn about basic microlensing parameterization and terminology and test that knowledge on a mini modeling Data Challenge. Topics covered:

3. Binary Lenses

We will use this session to explore a more complicated, binary-lens model and exercises to demonstrate the challenges of binary-lens fitting and common approaches to addressing them. We will fit that same event using three different methods:

  1. Start a fit from an uninformed guess
  2. Start with a grid search
  3. Start from an informed guess

Some of these methods are computationally expensive, so we will parallelize our efforts and discuss common challenges in microlensing binary-lens modeling, e.g., degeneracies, stochastic likelihood space, and higher-order effects.

4. Information Session and Q&A

Ask the demonstrators anything you would like to know about microlensing and/or the Data Challenge.

They will also provide details on: