Study Systematics on the ICM metallicity measurements Elena Rasia Chandra Fellow Physics Department, University of Michigan, Ann Arbor Columbus, Great Lakes Cosmology, June, 1 st 2007 In collaboration with Mazzotta P., Moscardini L., Borgani S., Dolag K., Ettori S., Tornatore L., Bourdin H. (submitted ApJ)

CLUSTERS OF GALAXIES VIEWPOINT OF COSMIC WEB LABORATORIES OF THE ICM PHYSICS Dolag, Meneghetti, Moscardini, Rasia, Bonaldi, 06 http: // Abell 1689 Abell 2390 & MS Key quantity: MASS Key quantities: Hydro-properties Gas density Temperature Pressure metals

CLUSTERS OF GALAXIES & COSMOLOGY: IMPORTANCE OF THE MASS FUNCTION Rosati, Borgani, Norman 02 Borgani & Guzzo 01 N(M,z) = Number of virialized object at redshift z with Mass M  [M,M+dM] (Press & Schechter 74, Jenkins et al. 01, Sheth & Tormen 99,00) Circles: Clusters with T>3keV THE MASS IS DIFFICULT TO MEASURE: NEED OF MASS PROXY

X-MAS Rasia et al. 07 Gardini et al. 04 See also: Mazzotta, et al 05, Rasia et al. 05, Rasia et al.06

MILLENIUM SIMULATION WITH GAS Non-cooling simulation (Pearce, Gazzola et al., in prep)Preheating simulation 4000 Mpc/h X 62.5 Mpc/h In collaboration with R. Stanek (PI), Gus Evrard and Brian Nord - see talk by Gus Evrard.  Scaling relations and Covariance between M - T x, f ICM, Y SZ, L x …

Color: Temperature Courtesy of Klaus Dolag Borgani et al Mpc SIMULATIONS Metalicity treatment: Tornatore et al.07

Galaxy Clusters as Laboratories for Stellar Evolution and History Sun like star Massive star

CLUSTERS AS LABORATORIES FOR THE STELLAR EVOLUTION AND HISTORY Chandra Comparison of Type Ia Supernova Remnants CRAB NEBULAE SN II 1987A SN II irr /2007/kepler/index.html

CLUSTERS AS LABORATORIES FOR THE STELLAR EVOLUTION AND HISTORY SNe IA PROGENITORS: white dwarf accreting matter from a nearby companion star Iron (major contributor), Silicon SNe II PROGENITORS: massive stars (with mass greater than 8 M sun )  -elements,as Oxygen, Magnesium, Silicon  [  /Fe] gives indication of (SN Ia/ SN II)  [Si/Fe] gives indication of yields of SN Ia

Silicon Profiles 6-9 keV 1-2 keV 2-3 keV Silicon profiles are well recovered for all the clusters in the sample free frozen

Oxygen & Magnesium Profile 8-12 keV 6-9 keV For systems with T < 5 keV, we perfectly recover Oxygen. Magnesium is difficult to detect at all temperatures. Large and hot systems show a systematic overestimate of Oxygen and Magnesium lines. free frozen

Interpretation: Oxygen and Magnesium At high temperatures, Oxygen and Magnesium are very weak. For both elements, slight changes in the continuum produce large deviation on the lines’ emissivity measurements. Multi temperature nature of the plasma 8 keV

Iron profile 8-12 keV 1-2 keV 2-3 keV Overestimate of Iron only for the cluster at temperature of 2-3 keV. Good agreement for hotter and colder systems. free frozen

1keV 4keV A 2-3 keV object is a combination of temperature: those larger than 2.5/3 give a large contribution to the Fe-K lines; those smaller, to the Fe-L lines => both groups of lines are pumped up by different-temperature plasmas Interpretation: Iron profile

T 1 =2 keV Z 1 =0.2 Norm 1 =1 T 2 =3keV Z 2 =0.1 Norm 2 =1 + RESULT: T = Z = N = The metallicity found is 20% larger (15  ) Interpretation: Iron profile EXPECTED: T = Z = N = # cnts: ,  2 = 539/506, reduced  2 = 1.08

Baumgartner et al. 05 The systematic overestimate of Fe for systems of 2-3 keV can reduce the significance of the bump of Baumgartner et al. plot Attention has to be paid to different [  /Fe] ratios… and to their interpretation Consequences

KEY POINTS Clusters are fantastic laboratories both for studying cosmology and for understanding the physics of the Intra Cluster Medium Necessity of X-MAS to compare Simulations and Observations 1:1 Simulations are now very powerful: large cosmological boxes are simulated with sophisticated physics.

SUMMARY ON METALLICITY Due to the multi-temperature nature of plasma in clusters, the measurement of elements that have weak emission compared to the continuum IS NOT A SOLID AND ROBUST ESTIMATE Iron estimate for systems of 2-3 keV can likely be biased towards higher values since this is a critical temperature range where we mix together plasma presenting either strong Fe-L or strong Fe-K lines. i) Silicon, ii) Oxygen for clusters cooler than 6 keV, iii) Iron for both cold systems (T 4 keV) ARE WELL RECOVERED