Observational Properties of Simulated Galaxies

Transcription

1 Observational Properties of Simulated Galaxies Illustris subhaloid: , camera: Illustris subhaloid: , camera: 3, field matched to SDSS objid: Computational Cosmology as seen through a Telescope bflags:3 1, field matched to SDSS objid: bflags:8 Collaborators: Paul Torrey, CAASTRO: The Changing Face of Galaxies Luc Simard, University g-ps model mask Connor Bottrell, of Victoria Sara L.science Ellison Illustris subhaloid: , camera: 1, field matched to SDSS objid: bflags: Illustris subhaloid: , camera: , field matched to SDSS objid: bflags: Illustris subhaloid: , camera: , field matched to SDSS objid: bflags:2

2 Introduction Galaxies demonstrate diverse morphological structures

3 Introduction Hydrodynamical Simulations Goal: reproduce the observed properties & morphologies of galaxies Illustris Simulation Vogelsberger+ 2014

4 sity of the NIR SED increases smoothly with increasing galaxy stellar mass, while the low star formation rates of the least massive galaxies and quenching of massive galaxies is indicated via low levels of UV emission. Introduction Synthetic images et al. SDSS gri composites gas cell Figure 5. Montage of two disk galaxies, respectively without a bar (top) and with a bar (bottom), viewed from three di erent viewing angles. The degree to which the observable strength of the bar depends on viewing angle can be quantified, and be used as a correction for visual classification studies. star particle + SED established theory of stellar shell formation via major (Hernquist 1992) and minor (Quinn Dupraz & Figure&6.Spergel Montage of a sample simulated disk 1984; galaxy in bands Torrey et al. Combes Quinn 1988; Kojima & Noguchi as labeled1986; withinhernquist the figure.& Each image has been scaled independently mergers. using an asinh scaling, with the non-linear transition 1997)

5 Methods Galaxies from z=0 of the Illustris Simulation with SDSS Realism Key components: subhaloid: camera: 1 r-band synthetic image PSF convolution + Poisson noise insertion into SDSS sky Goal: derive galaxy properties consistently with observed galaxies

6 Bottrell et al. 2016, MNRAS submitted Illustris subhaloid: , camera: 3, field matched to SDSS objid: bflags:3 ( for early access to catalogs) Public catalogs of 2D parametric decompositions of Illustris galaxies with full SDSS realism (bulge+disc and pure sersic) Illustris subhaloid: , camera: , field matched to SDSS objid: bflags:8 Processed with the same decomposition pipeline as catalogs by Simard et al Illustris subhaloid: , camera: , field matched to SDSS objid: bflags: Illustris subhaloid: , camera: , field matched to SDSS objid: bflags: Illustris subhaloid: , camera: , field matched to SDSS objid: bflags:2

7 Half-Light Radius, rhl_r Size Luminosity Relation SDSS Illustris Luminosity, M_r,b+d Illustris galaxies (red): larger, brighter, shallower slope for same masses

8 Size Luminosity Relations of Discs/Spheroids kpc)] 1.2 Disc-Dominated, (B/T)r 0.4 Slope = dex/mag Disc Dom., (B/T)< log10[rhlg,b+d / (h Half-Light Radius Bulge-Dominated, (B/T) 0.6 Bulge Dom., (B/T)>0.6 Slope = -27 dex/mag r Mg,B+D 21 5 log10 h SDSS Luminosity Size-luminosity relation is sensitive to morphology

9 Bulge to Total Fractions SDSS 1/N dn/d(log M? /M ) Illustris /N dn/d(log M? /M ) Stellar Mass, log M?/M Stellar Mass, log M?/M % 68 % 50 % 1/N dn/d(b/t)r,g2d 86 % 68 % 50 % Photometric (B/T)r,g2d 1.0 1/N dn/d(b/t)r,g2d Photometric (B/T)r,g2d In samples matched by mass and (low) redshift, Illustris is bereft of bulges where real galaxies have diverse morphologies

10 Half-Light Radius (kpc) Morphology Matched Size Luminosity Relation B/T + stellar mass (before) stellar mass only Luminosity, M_r,b+d Morphology matching remedies broad differences in the SL relation, but is left with primarily the disc SL relation

11 Photometric and Kinematic Bulge Fractions log M? /M Stellar Mass Photometric (b/t)r,phot(b/t) subhaloid: Galaxy Zoo Image subhaloid: Galaxy Zoo Image subhaloid: Galaxy Zoo Image (b/t)kin Kinematic (B/T) Photometric B/T systematically lower than kinematic B/T derived from stellar orbits. Lower mass galaxies most strongly affected.

12 Photometric and Kinematic Bulge Fractions 1.0 (B/T )r,phot (B/T )r,kin all galaxies in Illustris log[m?] [M ] Photometric B/T systematically lower than kinematic B/T derived from stellar orbits. Lower mass galaxies most strongly affected.

13 Summary New image-based comparison method for observed galaxies and hydrodynamical simulations Public Decomposition Catalogs and characterization of biases affects on structural measurements Bottrell et al. 2016, MNRAS submitted. for early access to catalogs Difference in Size-luminosity relation driven by a deficit of bulge-dominataed galaxies in Illustris for galaxies with logm*<11 [Msun] Discrepancy between kinematic and photometric B/T Thank you