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Study Systematics on the ICM metallicity measurements Elena Rasia Chandra Fellow Physics Department, University of Michigan, Ann Arbor In collaboration with Mazzotta P., Moscardini L., Borgani S., Dolag K., Ettori S., Tornatore L., Bourdin H. (submitted ApJ) Columbus, Great Lakes Cosmology, June, 1st 2007 CLUSTERS OF GALAXIES Abell 2390 & MS2137.3-2353 Abell 1689 VIEWPOINT OF COSMIC WEB Key quantity: MASS http: //www.astro.unipd.it/~cosmo/ LABORATORIES OF THE ICM PHYSICS Key quantities: Hydro-properties Gas density Temperature Pressure metals Dolag, Meneghetti, Moscardini, Rasia, Bonaldi, 06 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 4000 Mpc/h X 62.5 Mpc/h Non-cooling simulation (Pearce, Gazzola et al., in prep) Preheating simulation In collaboration with R. Stanek (PI), Gus Evrard and Brian Nord - see talk by Gus Evrard. Scaling relations and Covariance between M - Tx, fICM, YSZ, Lx … SIMULATIONS 275 Mpc QuickTime™ and a MPEG-4 Video decompressor are needed to see this picture. Courtesy of Klaus Dolag Metalicity treatment: Tornatore et al.07 Color: Temperature Borgani et al. 04 QuickTime™ and a YUV420 codec decompressor are needed to see this picture. Sun like star Galaxy Clusters as Laboratories for Stellar Evolution and History QuickTime™ and a YUV420 codec decompressor are needed to see this picture. Massive star CLUSTERS AS LABORATORIES FOR THE STELLAR EVOLUTION AND HISTORY http://chandra.harvard.edu/photo/2006/crab/index.html CRAB NEBULAE SN II http://chandra.harvard.edu/photo /2007/kepler/index.html http://imagine.gsfc.nasa.gov/Images/icons/adv_snr.gif QuickTime™ and a YUV420 codec decompressor are needed to see this picture. 1987A SN II irr Chandra Comparison of Type Ia Supernova Remnants CLUSTERS AS LABORATORIES FOR THE STELLAR EVOLUTION AND HISTORY SNe IA SNe II PROGENITORS: white dwarf accreting matter from a nearby companion star PROGENITORS: massive stars (with mass greater than 8 Msun ) Iron (major contributor), Silicon -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 2-3 keV 1-2 keV Silicon profiles are well recovered for all the clusters in the sample free frozen Oxygen & Magnesium Profile 8-12 keV 6-9 keV free frozen 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. 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. Plasma @ 8 keV Multi temperature nature of the plasma Iron profile 8-12 keV 1-2 keV 2-3 keV free frozen Overestimate of Iron only for the cluster at temperature of 2-3 keV. Good agreement for hotter and colder systems. Interpretation: Iron profile 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 Consequences • 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 Baumgartner et al. 05 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 i) Silicon, ii) Oxygen for clusters cooler than 6 keV, iii) Iron for both cold systems (T < 2 keV) and hot systems (T > 4 keV) ARE WELL RECOVERED 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.
