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Testing asteroseismology with Gaia DR2: Hierarchical Models & the Red Clump

Bb1020684e201eef0a2b34f8f7ab214d?s=47 Oliver Hall
December 17, 2018

Testing asteroseismology with Gaia DR2: Hierarchical Models & the Red Clump

This presentation, which I gave at the December 2018 Birmingham-Warwick Science Meet-Up, is an update to a previous talk given at KASC/TASC in July 2018 (https://speakerdeck.com/ojhall94/testing-asteroseismology-with-gaia-dr2-luminosity-of-the-red-clump).

We use hierarchical models to constrain a population of Red Clump stars in both asteroseismic and Gaia data. We suggest a shift of ~-100K to temperatures used in the asteroseismic analysis will find an agreement for the luminosity of the Red Clump for both the Gaia data and the seismic data.

Hall et al. 2019 is submitted pending review.

Bb1020684e201eef0a2b34f8f7ab214d?s=128

Oliver Hall

December 17, 2018
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  1. @asteronomer ojhall94 Oliver J. Hall Guy Davies, Yvonne Elsworth, Andrea

    Miglio, Bill Chaplin, Saniya Khan, Rafael Garcia, Thomas North Birmingham-Warwick Science Meet-Up University of Warwick 17th Dec 2018 Testing asteroseismology with Gaia DR2: Hierarchical Models & the Red Clump !1
  2. Hierarchical Models & the Red Clump !2 Systematics Brogaard+2018 Lindegren+2018

    Asteroseismology Gaia DR2 Parallaxes
  3. Hierarchical Models & the Red Clump

  4. Hierarchical Models & the Red Clump μ σ Q σo

    ̂ Mi σ ̂ Mi Model Population
  5. Hierarchical Models & the Red Clump == Lets use this!

    Population Individual stars (5 / 5576)
  6. Hierarchical Models & the Red Clump μ σ Q σo

    Mi ̂ Mi σ ̂ Mi Model ‘True’ Population Individual stars (5 / 5576)
  7. Hierarchical Models & the Red Clump m, ϖ, ̂ A

    Fitting to: Everything else is marginalized!
  8. Hierarchical Models & the Red Clump !8 Lets make our

    changes, and see how it affects the Clump!
  9. Hierarchical Models & the Red Clump What about using Gaia

    to find the Clump?
  10. Hierarchical Models & the Red Clump !10 If we believe

    Gaia, what does that mean for seismology? -100 K -200 K
  11. Hierarchical Models & the Red Clump @asteronomer ojhall94 In summary…

    » Used hierarchical models to locate the RC in seismic & Gaia data » Asteroseismology finds the Clump well, but has lots of systematic scatter » Gaia finds the Clump less precise, but more consistent » We can perform a quantitative calibration of seismology using Gaia, but more work is required! -100K -200 K
  12. Hierarchical Models & the Red Clump Asteroseismology Gaia DR2 Parallaxes

    νmax νmax,⊙ Δν Δν⊙ Teff Teff,⊙ R R⊙ L Mbol,⊙ Bolometric Correction ̂ Mλ ϖ ϖzero point Σ ϖ r Aλ mλ ̂ Mλ Teff Teff
  13. Hierarchical Models & the Red Clump !13 How would this

    affect a calibration of Gaia?