Transcript ppt
Lightcones for Munich Galaxies Bruno Henriques Outline 1. Model to data - stellar populations and photometry 2. Model to data - from snapshots to lightcones 3. Results - pencil beams 4. Results - all-sky cones Mass to Light Stellar Population Synthesis Metallicity + Age +IMF 1 exp sec A 2.5log sec 7 April 2016 Luminosity of a stellar population Dust Model 3 Full Emission Spectra Direct comparison to observed frame apparent magnitudes Test SED fitting / K-corrections Reliability of assumed star formation histories Test determinations of mass 7 April 2016 4 Different Stellar populations Test the impact of stellar populations modelling in the observed galaxy properties. In past evolutionary population synthesis codes, the K-band was mostly determined by old populations (e.g. Bruzual & Charlot 2003, PEGASE, Starburst99) i z J K The inclusion of the TP-AGB phase means that intermediate-age populations will contribute significantly to the near infra-red emission from galaxies (Marasto 2005, Charlot & Bruzual 2007) (see also Henriques, Maraston, Monaco et al. (2010)) 7 April 2016 5 The semi-analytic is built on top of the dark matter distribution and has outputs only at given snapshots. (despite galaxy properties being computed in smaller steps ~ 6 Myr ) z=5.7 z=1.4 From snapshot/box output z=0 7 April 2016 to lightcones 6 Lightcones dcom zn zi Comoving distance Redshifts - snapshots (zi+zi-1)/2<z<(zi+zi+1)/2 Lightcones only few replications, distant in redshift Mass to light obs_frame rest_frame Number Counts & Zdist First tests can be performed directly in the observed frame with only few derivations applied to data. bright near-by and faint distant galaxies Intermediate redshifts dominated by faint objects Henriques, White, Lemson, et al. 2012 Rest-frame Colours and LFs More informative tests can be done for rest-frame properties in order to obtain a comprehensive picture. Optical-near-infrared color, separates passive from dust obscured galaxies Large differences between stellar populations Allsky Lightcones Selection in iAB< 21.0 - 100deg2 - comparable to modern wide surveys BOSS observed-frame color selection criteria can be matched The model can be used to analyze the selection in terms of fundamental quantities Maraston, Pforr, Henriques, et al. 2012 Stellar Mass of Massive Ellipticals The numbers of massive galaxies are similar in model and data reflecting the slow evolution of these objects at later times Conclusions Narrow and wide lightcones constructed to match modern surveys. Wide photometric coverage that can be used to test derivation of fundamental quantities from observations. Large range of properties can be closely compared with available data to identify possible tensions in theory. Simulations to Observations Mass to light Boxes to cones Motivation Why use a phenomenological approach to study galaxy formation? Because we should. The physics of galaxy formation are complex but observations suggest they must obey simple relations. Still, we do not have a good understanding and cannot work from first principles, so models must be observationally based. Fast method to compute the evolution of the galaxy population across cosmic time for samples as large as modern surveys. Scaling Relations Tully-Fisher Many aspects of the physics that govern galaxy formation depend simply on galaxy and dark matter properties as indicated by observed scaling relations. BlackHoleBulgeMass SFR-Gas _________________________________________________ ___________________________________________________________ Even if direct simulations reach high resolution and significant volumes they face the same problems due to un-resolved physics! TB-AGB TB-AGB + RHeB Van der Wel, Franx, Wuyts, et al. 2006 SSP Chandra Deep Field - South ACS+IRAC+J&H filters 7 April 2016 20 Maraston, Daddi, Renzini, et al. 2006 Older then the Universe! Undetected in MIPS! What are the implications for galaxy formation models? 7 April 2016 21 Marchesini 2009 Optical to mid-infrared data GOODS – Giavalisco et al. 2004 MUSYC – Gawiser et al. 2006 7 April 2016 22 CB07 M05 CB07 BC03 7 April 2016 Henriques, Maraston, Monaco, et al. (Astro-ph: 1009.1392) 23