Stellar-to-Halo Mass Relation in X-ray Groups at 0.5<z<1

Transcription

1 Stellar-to-Halo Mass Relation in X-ray Groups at 0.5<z<1 Shannon Patel Dan Kelson, Rik Williams, John Mulchaey Carnegie Observatories X-ray View of Galaxy Ecosystems July 9, 2014

2 Stellar-to-halo mass relation Star formation e ciency 0.1 Behroozi+13 Kravtsov M * / M h Behroozi et al. (2010) Reddick et al Moster et al (AM) Moster et al (AM) Guo et al (AM) Wang & Jing 2009 (AM+CC) Zheng et al (HOD) Yang et al (CLF) Yang et al. 2009a (CL) Hansen et al (CL) Lin & Mohr 2004 (CL) Behroozi et al Genel, S. et al M h [M ] O 0.2 M * /(M 200c Ω b /Ω m ) 0.5 solid full mass dashed fiducial mass (a) Stellar mass to halo mass relation z=0 z=1 z=2 z=3 z=4 M * /(M 200c Ω b /Ω m ) 0.1 Fig. 11. The 0.1 stellar mass fraction of the central galaxy in units of the universal baryon fraction within radius R 200 as a function of total halo mass M 200. The stellar masses for clusters analyzed in this study and in G13 are 0.05 Genel+14 shown by red crosses, while the other symbols are the same asz=0 in Figure 10. The lines show the relations using abundance matching ansatz z=1 in this work using the Bernardi 0.05 et al. (2013) stellar mass function and previous results by Moster et al. (2013) and Behroozi et al. (2013b). z=2 z=3 z= which could 0.03 be considered to be an equivalent of such component, 14.5contributes 11 only % 12.5 of stellar 13 mass 13.5 (e.g., 14Purcell log 10 (M 200c [M sun ]) log 10 (M 200c [M sun ]) et al. 2007) (b) E ects of physics variation 4.1. E ects of IMF Figure 4. Left panel: The mean relation between stellar mass and halo mass for central galaxies at redshifts 0 6 z 6 4, normalised

3 Galaxy group ecosystem is important at z<1 Grow into clusters by z~0 Pre-processing/environmental quenching, etc. Hierarchical growth at z<1 leads to a dramatic increase in their number density

4 Rise of groups at z<1 in the Carnegie-Spitzer-IMACS (CSI) survey cumulative number density = total group stellar mass redshift ure 3. Number density of groups in three stellar mass bins. For the t Williams+12b

5 Galaxy group ecosystem is important at z<1 Grow into clusters by z~0 Pre-processing/environmental quenching, etc. Hierarchical growth at z<1 leads to a dramatic increase in their number density What is the efficiency of forming/assembling stars in such halos at these redshifts? Current measurements are sparse in this mass/redshift regime

6 Sample selection Groups 20 X-ray groups at 0.5<z<1 from Chandra Deep Field South (CDFS) catalog of Finoguenov et al Deepest X-ray dataset to date (Chandra + XMM-Newton) X-ray view is important as it allows reliable detection of groups at high redshift Galaxies Carnegie-Spitzer-IMACS (CSI) survey (Kelson et al. 2014) Low resolution spectroscopic survey covering ~15 sq. deg: σ z /(1+z)~0.008 for sample used here IRAC 3.6-μm selected: low stellar mass limit Uniform survey, completeness well understood and mapped in magnitude, color, and spatial position

7 Mass measurements Total halo mass, M 200 From Finoguenov+2014: weak lensing L X -M 200 calibration of Leauthaud+2010 in COSMOS at similar redshifts Total group stellar mass, M Mass within R<R 200 at Δz/(1+z)<0.02 (e.g., similar to Giodini+09) Subtract off average background contribution measured from apertures across the field Corrections for spectroscopic completeness, stellar mass limit of survey, etc. Error analysis takes all of this into account

8 Example groups in CDFS

9 M -M 200 relation at 0.5<z<1 Samples: CDFS(20) - this work COSMOS(69) - George+11 GCLASS(4) -van der Burg+14 CDFS sample extends relation to low group masses: M /M200~3%

10 M -M 200 relation at 0.5<z<1: slope Samples: CDFS(20) - this work COSMOS(69) - George+11 GCLASS(4) -van der Burg+14 CDFS+COSMOS slope: 0.84±0.10 CDFS+COSMOS+GCLASS slope: 0.74±0.07 Slope less than unity: M /M200 decreases in more massive halos

11 M -M 200 relation at 0.5<z<1: scatter Samples: CDFS(20) - this work COSMOS(69) - George+11 GCLASS(4) -van der Burg+14 CDFS+COSMOS slope: 0.84±0.10 CDFS+COSMOS+GCLASS slope: 0.74±0.07 Observed scatter: σ=0.25 dex Use M as a proxy for M200

12 No strong evolution in M /M 200 in the group regime M /M200 Arrows: z~0 from Kravtsov+14 (abundance matching) redshift

13 Summary Group ecosystem plays an important role in galaxy evolution at z<1 Significant growth in number density of groups at z<1 (Williams+12b) CSI galaxies + X-ray detected groups in CDFS probe efficiency of forming/ assembling stars in such halos Stellar-to-halo mass in low mass X-ray groups at 0.5<z<1: At M 200 ~2x10 13 M (i.e., previously unexplored territory): M /M 200 ~3% Small scatter (~0.25 dex): stellar mass a good proxy for halo mass calibration for CSI survey group catalog Decreasing trend with higher mass when including samples over a larger mass range No strong evolution in the stellar-to-halo mass ratio in the group regime since z~1 Paper on the arxiv soon

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