Seminarium: Estimating stellar distances

  • Datum: –15.00
  • Plats: Zoom: https://uu-se.zoom.us/j/64257004440
  • Föreläsare: Coryn Bailer-Jones, Max Planck Institute for Astronomy, Heidelberg
  • Kontaktperson: Sofia Ramstedt
  • Seminarium

Gaia does not measure distances. Gaia measures parallaxes, and has done so superbly for nearly one and a half billion stars. But the conversion to distances is complicated in the general case of non-negligible relative uncertainties, which is the case for most stars. This problem is addressed in a probabilistic approach; the inference of distances then boils down to adopting the appropriate likelihood and prior. I will describe how we have done this for the Gaia releases to produce catalogues of distances and - crucially important - their uncertainties. This Bayesian approach allows one to incorporate other measurements that also contain distance information, such as colour and magnitude. I will discuss how we did this, the choices we made, and how one could adapt this approach to other circumstances.

 

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We will run with the following setup:
- The zoom meeting will open at 13.45 so that you can log on and try it out.
- Participants should mute their microphones unless they have a question.
- Questions are allowed during the talk. Just raise your hand in the zoom app.
- After the talk has finished, unmute for applause.
- If possible, keep your video on during the full seminar so that the speaker gets visual feedback while talking.
- Questions after the talk will be administered as follows; raise your hand in the app and Sofia will chair and give the word.

- Finally, after the talk and question sessions are finished, the meeting will remain open for an informal ”bring-your-own-fika” if you want to hang around and chat with your colleagues and the speaker.