Asteroseismology for Galactic Archaeology:

bridging two fields

Luca Casagrande Victor Silva Aguirre

Dennis Stello, Aldo Serenelli Daniel Huber, Katie Schlesinger, Ralph Schönrich, Sofia Feltzing

Asteroseismology for Galactic Archaeology:

bridging two fieldswww.mso.anu.edu.au/saga

Casagrande, Silva Aguirre, Stello et al. 2014, ApJ, 787, 110Casagrande, Silva Aguirre, Schlesinger et al. 2015, MNRAS, submitted

Luca Casagrande Victor Silva Aguirre

Dennis Stello, Aldo Serenelli Daniel Huber, Katie Schlesinger, Ralph Schönrich, Sofia Feltzing

WFC @ INT: •2.5 m •34’ x 34’ FOV •Strömgren uvby • ~30 nights (2012-2014) • ~40 nights (2015)

Isaac Newton Telescope Kepler field

Kepler is dead, long live to Kepler!

WFC @ INT: •2.5 m •34’ x 34’ FOV •Strömgren uvby • ~30 nights (2012-2014) • ~40 nights (2015)

Isaac Newton Telescope Kepler field

Kepler is dead, long live to Kepler!

WFC @ INT: •2.5 m •34’ x 34’ FOV •Strömgren uvby • ~30 nights (2012-2014) • ~40 nights (2015)

Isaac Newton Telescope Kepler field

Kepler is dead, long live to Kepler!

WFC @ INT: •2.5 m •34’ x 34’ FOV •Strömgren uvby • ~30 nights (2012-2014) • ~40 nights (2015)

Isaac Newton Telescope Kepler field

Kepler is dead, long live to Kepler!

~ 1000 red giants

Image credit: NASA/JPL-Caltech

Image credit: NASA/JPL-Caltech

⦿

Galactic Evolution (=baryons!)e.g. Lynden-Bell 1975, Tinsley 1980, Matteucci & Francois 1989, Chiappini et al. 1997, Schönrich & Binney (2009)

⦿

⦿

Galactic Evolution (=baryons!)e.g. Lynden-Bell 1975, Tinsley 1980, Matteucci & Francois 1989, Chiappini et al. 1997, Schönrich & Binney (2009)

⦿

⦿

Galactic Evolution (=baryons!)

AMR

e.g. Lynden-Bell 1975, Tinsley 1980, Matteucci & Francois 1989, Chiappini et al. 1997, Schönrich & Binney (2009)

[Fe/

H]

⦿Schönrich & Binney (2009)

age

Galactic Evolution (=baryons!)e.g. Lynden-Bell 1975, Tinsley 1980, Matteucci & Francois 1989, Chiappini et al. 1997, Schönrich & Binney (2009)

AMR

[Fe/

H]

⦿

age

Galactic Evolution (=baryons!)e.g. Lynden-Bell 1975, Tinsley 1980, Matteucci & Francois 1989, Chiappini et al. 1997, Schönrich & Binney (2009)

AMR

[Fe/

H]

⦿

age

Galactic Evolution (=baryons!)e.g. Lynden-Bell 1975, Tinsley 1980, Matteucci & Francois 1989, Chiappini et al. 1997, Schönrich & Binney (2009)

AMR

[Fe/

H]

⦿

AVR

age e.g. Holmberg et al. (2007), Casagrande et al. (2011)

age

Schönrich & Binney (2009)

Strömgren (uvby)→ [Fe/H]

Broad-band photometry→ Teff ← Asteroseismology

(evol. phase, Δν

, νMAX )

Radii, Masses,

distances, ages,

metallicities

✓ Kepler selection function: how well the red giants observed by Kepler are representative of the underlying population of giants in the field. (benchmarking against an unbiased sample).

✓ Target selection effects: once the selection function is known, how this bias the observations. (population synthesis).

✓ Kepler selection function: how well the red giants observed by Kepler are representative of the underlying population of giants in the field. (benchmarking against an unbiased sample).

✓ Target selection effects: once the selection function is known, how this bias the observations. (population synthesis).

all stars

Kepler selection function

V < 14

Kepler selection function

V < 14

GCS dwarfs

-2.0 giants

Kepler selection function

V < 14

seismic

GCS dwarfs

-2.0 giants

Kepler selection function

V < 14

seismic

GCS dwarfs

-2.0 giants

Kepler selection function

unbiased sample

Kepler sample

~400 red giants

V < 14

seismic

GCS dwarfs

-2.0 giants

Kepler selection function

unbiased sample

Kepler sample

~400 red giants

Target selection effects

Stellar Mass gradient

height above the Galactic plane (kpc)

Stellar Mass gradient

height above the Galactic plane (kpc)

Age gradient

height above the Galactic plane (kpc)

Age gradient

height above the Galactic plane (kpc)

Age gradient

height above the Galactic plane (kpc)

4 ± 2 Gyr / kpc

NOW Lookback time

Age-metallicity relation

NOW Lookback time

Age-metallicity relation

NOW Lookback time

Age-metallicity relation

ConclusionsADVANCES IN GALACTIC ASTRONOMY FROM

ASTEROSEISMOLOGY

Vertical structure of the disk:

vertical age gradientage-metallicity

suggest quiescent evolution for Milky Way disc over the last 10 Gyr, thus highlighting the importance of

secular processes in disc evolution