LEGA-C The Physics of Galaxies 7 Gyr Ago Arjen van der Wel Max Planck Institute for Astronomy, Heidelberg
How do galaxies assemble their stellar bodies? Collection of large samples at large lookback times Redshift surveys Multi-wavelength photometric surveys Hubble Space Telescope surveys Deep spectroscopic surveys
How do galaxies assemble their stellar bodies? Collection of large samples at large lookback times Redshift surveys Multi-wavelength photometric surveys Hubble Space Telescope surveys Deep spectroscopic surveys
How do galaxies assemble their stellar bodies? Collection of large samples at large lookback times Redshift surveys Multi-wavelength photometric surveys Hubble Space Telescope surveys Deep spectroscopic surveys
How do galaxies assemble their stellar bodies? Collection of large samples at large lookback times Redshift surveys Multi-wavelength photometric surveys Hubble Space Telescope surveys Deep spectroscopic surveys
Where we are now We have a detailed census and phenomenological description Madau & Dickinson (2014): of 3.9 Gyr. Half of the stellar mass observed today was formed before a redshift z =1.3. About 25% formed before the peak of the cosmic star-formation ratedensity,andanother 25% formed after z =0.7. Less than 1% of today s stars formed during the epoch of SFR history and Mass Function integrations agree: 40-60% of stars formed before and after z = 1
How do galaxies assemble their stellar bodies? Collection of large samples at large lookback times Redshift surveys Multi-wavelength photometric surveys Hubble Space Telescope surveys Deep spectroscopic surveys
How do galaxies assemble their stellar bodies? Collection of large samples at large lookback times Redshift surveys Multi-wavelength photometric surveys Hubble Space Telescope surveys Deep spectroscopic surveys
Evolution of the Size Distribution CANDELS + 3D-HST: van der Wel et al. (2014a)
Evolution of the Size Distribution CANDELS + 3D-HST: van der Wel et al. (2014a)
Evolution of the Size Distribution CANDELS + 3D-HST: van der Wel et al. (2014a)
Where we are now We have a detailed census and phenomenological description No change in M* (in Schechter) over 10 Gyr Evolution in number density Quenching Star formation inside-out Assembly through merging
Where we are now We have a detailed census and phenomenological description No change in M* (in Schechter) over 10 Gyr Evolution in number density Quenching Star formation inside-out Assembly through merging allowing us to make sweeping statements, e.g., The majority of all stars formed in disk galaxies with similar mass as the present-day Milky Way (van der Wel et al. 2014b)
How do galaxies assemble their stellar bodies? Collection of large samples at large lookback times Redshift surveys Multi-wavelength photometric surveys Hubble Space Telescope surveys Deep spectroscopic surveys
How do galaxies assemble their stellar bodies? Collection of large samples at large lookback times Redshift surveys Multi-wavelength photometric surveys Hubble Space Telescope surveys Deep spectroscopic surveys
Large Early Galaxy Astrophysics Census 128-night Public Spectroscopic Survey with VLT / VIMOS Observations: December 2014 - Spring 2018 >3000 z=0.6-1 galaxies (K-selected, UltraVISTA Muzzin+13) 20hr integrations; typical S/N = 20/Å R = 2500, λ = 6000-9000 Å Stellar ages and metallicities Dynamical masses Gas-phase metallicities
Large Early Galaxy Astrophysics Census 128-night Public Spectroscopic Survey with VLT / VIMOS Observations: December 2014 - Spring 2018 >3000 z=0.6-1 galaxies (K-selected, UltraVISTA Muzzin+13) 20hr integrations; typical S/N = 20/Å R = 2500, λ = 6000-9000 Å Stellar ages and metallicities Dynamical masses Gas-phase metallicities
Large Early Galaxy Astrophysics Census 128-night Public Spectroscopic Survey with VLT / VIMOS Observations: December 2014 - Spring 2018 >3000 z=0.6-1 galaxies (K-selected, UltraVISTA Muzzin+13) 20hr integrations; typical S/N = 20/Å R = 2500, λ = 6000-9000 Å Stellar ages and metallicities Dynamical masses Gas-phase metallicities
Large Early Galaxy Astrophysics Census PI: Arjen van der Wel (MPIA) Survey Manager: Kai Noeske (MPIA) Survey Scientists: Rachel Bezanson (Arizona) Dynamics Anna Gallazzi (Arcetri) Chemical abundances Camilla Pacifici (STScI) Star formation histories Co-I s: Eric Bell (Michigan) Gabe Brammer (STScI) Stephane Charlot (IA Paris) Priscilla Chauke (MPIA) Marijn Franx (Leiden) Ivo Labbe (Leiden) Michael Maseda (Leiden) Juan Carlos Munoz (ESO) Adam Muzzin (Cambridge) Hans-Walter Rix (MPIA) David Sobral (Lisbon) Jesse van de Sande (Sydney) Pieter van Dokkum (Yale) Vivienne Wild (St. Andrews) Christian Wolf (ASU)
Typical spectrum from redshift surveys
What LEGA-C Spectra Reveal z = 0.70 Stellar mass: M* = 1.4 +/- 0.5 x 10 11 Msol 16 ACS image
What LEGA-C Spectra Reveal z = 0.70 Stellar mass: M* = 1.4 +/- 0.5 x 10 11 Msol 16 ACS image
What LEGA-C Spectra Reveal Ca Ca Hδ Ca G Hɣ Fe Ca z = 0.70 Stellar mass: M* = 1.4 +/- 0.5 x 10 11 Msol 16 Stellar velocity dispersion: 154 +/- 6 km/s Dynamical mass: 1.5 +/- 0.3 x 10 11 Msol Fe Fe Hβ Fe Mean stellar age: 2.9 +/- 0.3 Gyr Metallicity: 65% +/- 7% solar
We now have collected 23% of the data - High Sersic index - Low Sersic index - Inclined disks
Spectral Properties vs. Structure High-Sersic index galaxies
Spectral Properties vs. Structure Low-Sersic index galaxies
Star Formation History Distribution of age indicators: D4000 and Hδ Kauffmann+03 (SDSS; z < 0.1)
Star Formation History Distribution of age indicators: D4000 and Hδ 530 LEGA-C galaxies
Spectral Properties vs. Structure Face-on and Edge-on Disks
Summary and Outlook LEGA-C is a 128-night survey with VLT/VIMOS: deep continuum spectroscopy of >3000 galaxies at z = 0.6 1 LEGA-C will reveal the physics of galaxy formation by measuring the evolution of stellar populations over the past 7 Gyr Observations started in 11 months ago; we have collected 23% of data First Data Release (spectra) by June 1st, 2016 Second Data Release (spectra + phys. parameters) by Dec 1st, 2016
Resolved stellar kinematics at z = 1 van der Wel & van der Marel 2008