The Luminosity-Temperature Relation of the XXL100

1. The Luminosity-Temperature Relation of the XXL100 • F. Pacaud (Bonn) • B. Maughan (Bristol) • N. Clerc (MPE) • G. Smith (Birmingham) • M. Lieu (Birmingham) • M. Pierre (SEA Saclay) • And many more…. The X-ray Universe 2014 – Paul Giles

2. The Luminosity-Temperature Relation • In gravity only models, assuming clusters are self similar, a power law relation between L and T with a slope of 2 is expected. • Observations find a steeper slope ~ 3 (e.g. Markevitch 1998, Ettori et al. 2004, Pratt et al. 2009, Hilton et al. 2012, Maughan et al. 2012) • Evolution given by E(z)γ (for SS γ= 1). Recent evidence for weaker than SS evolution (Pacaud et al. 2007, Reichert et al. 2011, Clerc et al. 2012,14, Hilton et al. 2012) • What is the driving force behind this? AGN, biases…. Pratt et al. 2009 The X-ray Universe 2014 – Paul Giles

3. The Luminosity-Temperature Relation • In gravity only models, assuming clusters are self similar, a power law relation between L and T with a slope of 2 is expected. • Observations find a steeper slope ~ 3 (e.g. Markevitch 1998, Ettori et al. 2004, Pratt et al. 2009, Hilton et al. 2012, Maughan et al. 2012) • Evolution given by E(z)γ (for SS γ= 1). Recent evidence for weaker than SS evolution (Pacaud et al. 2007, Reichert et al. 2011, Clerc et al. 2012,14, Hilton et al. 2012) • What is the driving force behind this? AGN, biases…. Pratt et al. 2009 Hilton et al. 2012 The X-ray Universe 2014 – Paul Giles

4. Cluster Sample • Initial selection of 180 clusters from the brightest in the XXL survey (M. Pierre talk) • Selected the 100 brightest clusters based upon flux within 60’’ • Corresponds to a flux limit of 3x10-14 ergs s-1 The X-ray Universe 2014 – Paul Giles

5. Cluster Sample The X-ray Universe 2014 – Paul Giles

6. Cluster Analysis • Redshifts • 87 spectroscopic • 10 photometric • Sextractor used for X-ray source detection • Spectral analysis • Fit in 0.4 – 7.0 keV band • Use cstat statistic with 5 cnts/bin in background, applied to source • Use local backgrounds • Masses derived from a WL MT relation (M. Lieu, G. Smith) The X-ray Universe 2014 – Paul Giles

7. Credit: M. Lieu, G. Smith The MT Relation

8. LX – kT Relation (non bias corrected) Giles et al. in prep The X-ray Universe 2014 – Paul Giles

9. Modeling biases using Bayesian statistics HMFcalc Credit: F. Pacaud A method based on Mantz et al. 2010 The X-ray Universe 2014 – Paul Giles

10. Modeling biases using Bayesian statistics The X-ray Universe 2014 – Paul Giles

11. Modeling biases using Bayesian statistics The X-ray Universe 2014 – Paul Giles

12. LX – kT Relation (bias corrected) Giles et al. in prep The X-ray Universe 2014 – Paul Giles

13. LX – kT Relation (bias corrected) BCES slope = 3.27±0.35 Bias slope = 2.75±0.17 Evolution = 0.31±0.56 Giles et al. in prep The X-ray Universe 2014 – Paul Giles

14. Take home messages • Only second study of LT relation to incorporate bias using the mass function and selection function (First Mantz et al. 2010) • Find a weaker than self similar evolution of the LT relation The X-ray Universe 2014 – Paul Giles

15. Summary • Studied a sample of 100 clusters drawn from the XXL survey • Using a simple BCES regression fit to the LT relation, find results consistent with previous studies • Outlined a model to take into account the bias, utilizing the selection function and mass function • Using this model, we fit LT relation, finding a shallower slope and evidence for weaker than self similar evolution The X-ray Universe 2014 – Paul Giles