Abundance studies using Xray spectroscopy of clusters of galaxies

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Abundance studies using X-ray spectroscopy of
clusters of galaxies

• Jelle S. Kaastra
• Collaborators
• Norbert Werner, Jelle de Plaa,
• Aurora Simionescu, Jacco Vink

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Outline

• Importance clusters
• Observational challenges
• Enrichment by supernovae
• Enrichment by winds
• Future prospects
• Conclusions

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1. Importance clusters of galaxies for abundance
studies

• Largest bound structures
• Fair samples of the Universe
• Deep potential wells, retains most of the gas
• Hot gas no significant hiding of metals in
  dust ( more gas than stars)?
• Spatial extent allows mapping

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Abundance diagnostics hot gas in collisional
ionisation equilibrium
T 1 keV
T 0.2 keV
T 5 keV
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Which elements can we see?
K-shell

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Powerful X-ray eyes XMM-Newton

• 3 imaging CCDs (EPIC) with moderate energy
  resolution
• 2 Reflection Grating Spectrometers (RGS) with
  high spectral resolution

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2. Observational challenges

• Fe bias
• Complex temperature structure

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The Fe bias
Multi-T
1T

• 1T models sometimes too simple e.g. in cool
  cores
• Using 1T gives biased abundances (Fe-bias, Buote
  2000)?
• Example core M87 (Molendi Gastaldello 2001)?

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Complex temperature structure I(de Plaa et al.
2006)?

• Sérsic 159-3, central 4 arcmin
• Better fits 1T?wdem?gdem
• Implication for Fe 0.36?0.35?0.24
• Implication for O 0.36?0.30?0.19

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Temperature maps(Hydra A, Simionescu et al.
2008)?
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Complex temperature structure II(Simionescu et
al. 2008)?

• Example Hydra A
• Central 3 arcmin
• Full spectrum Gaussian in log T (s0.2)?
• 1T fits individual regions also Gaussian
• Confirmed by DEM analysis (blue purple)?

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Implications for Fe abundance(Simionescu et al.
2008)?

• Central 3 arcmin Hydra A, 1T models
• (errors on Fe 0.01 to 0.02)?

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3. Enrichment by supernovae
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Supernova yields core collapse
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Supernova yields Ia
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Decomposing abundances into SN types(De Plaa et
al. 2006)?

• Deep exposure XMM-Newton Sérsic 159-3
• Data include RGS
• 50 SN Ia by number
• Ca problem

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Another case 2A 0335096(Werner et al. 2006)?

• Current best case deep XMM-Newton observation of
  one of brightest clusters
• First evidence of traces of Cr (0.50.2 Solar)?

2A 0335096, Werner et al. 2005
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Decomposing 2A 0335096(Werner et al. 2006)?

• Use here WDD model
• Central 3 arcmin
• Sn Ia 25
• Increases to 37 in 3-9 arcmin annulus
• Ni W7 model predicts more
• Also here Ca problem

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Analysis of a large sample (De Plaa et al. 2007)?

• 22 clusters, 685 ks net exposure
• Taken from HIFLUGCS sample (Reiprich Böhringer
  2002)?
• All spectra extracted from within 0.2 R500
• Use wdem model

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Solution to the Ca problem(De Plaa et al. 2007)?

• Also sample shows Ca excess
• Problem solved by adopting SN Ia yields based on
  Tycho SNR (Badenes et al. 2006)?
• Best fit Ia/(Iacc) number ratio 0.440.05

WDD
Tycho
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Sample mean abundance ratios(De Plaa et al.
2007)?
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Comparison between clusters(Simionescu et al.
2008)?

• 6 clusters with deep exposures, taken from
  literature
• Most have 30-40 contribution Ia
• Hard to discriminate between Ia models, but see
  extremes Hydra A / M87

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Radial profiles example 2A 0335096(Werner et
al. 2006)?
S
Si
Fe
Ar
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Comparison between clusters radial
profiles(Simionescu et al. 2008)?

• All elements have decreasing abundances
• Also valid for O (contrary to earlier suggestions
  of flat O profile, Tamura et al. 2004)?

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Abundance ratios constant? (Simionescu et al.
2008)?

• Si/Fe flat within 0.1 R200, maybe break at
  0.05R200
• O/Fe increases, but only slightly per dex in
  radius, O/Fe increases by 0.250.09 (Fe decreases
  by 0.72)?

Si/Fe
O/Fe
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Consequences of flat oxygen profiles(Simionescu
et al. 2008)?

• Flattish O/Fe profiles ? not only Ia contribute
  to core enrichment
• Ram pressure stripping works already at Mpc scale
  (compare to 130 kpc core Hydra A)?
• Continued cc SN activity over past 1010 year?
• Early central enrichment cc SN?

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Cosmic feedback(Simionescu et al. 2006, 2007)?

• In M87, radio lobes show cool, enriched material
  levitated by the AGN outflow
• Similar results in Hydra A

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4. Enrichment by winds
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XMM-Newton RGS results

• Reflection Grating Spectrometer optimal for point
  sources
• But still the best for moderately extended
  sources, like cooling cores of clusters
• ?? (Å) 0.138 ?? (arcmin)?

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RGS results M 87(Werner et al. 2006)?

• Exposure time 169 ks
• Lines from O, N, C
• C/Fe 0.740.13
• N/Fe 1.620.21
• O/Fe 0.590.04
• Ne/Fe 1.250.12
• Mg/Fe 0.600.06
• Fe 1.060.03
• ? AGB winds for CN!

Continuum-subtracted RGS spectrum
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Nitrogen with RGS other cases

• M87 N/Fe 1.620.21
• 2A 0335096 (Werner et al. 2006) 1.30.4
• Sérsic 159-3 (De Plaa et al. 2006) 0.00.5
• Centaurus (Sanders et al. 2008) 1.5-3
• Need for more deep exposures with RGS

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Groups of galaxies

• O/Fe ratio 0.5-0.6 x Solar in 4 groups
• N/Fe 1.1-1.2 x Solar in NGC 4472 NGC 4636, but
  1.6 in M87
• Need more data this year deeper spectra of NGC
  5044 NGC 5813

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5. Future prospects

• Long term XEUS (ESA), Con-X (NASA) gt2018 (30 x
  effective area EPIC, resolution RGS, imaging)?
• Mid-term NeXT (Japan) 2013/14
• Short term (2011-2012)
• SXC (SpektrRG X-ray Calorimeter
• (Netherlands, USA, Japan, Germany, Russia)?

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Future SXC
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SXC Measuring clusters ISM simultaneously
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How accurate can we getcomparison XMM-Newton
with SXC
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Which elements will we see?(XEUS)?
K-shell

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6. Conclusions

• XMM-Newton observations of clusters of galaxies
  can disentangle contributions different SN types
  in clusters of galaxies
• In a few cases, CN abundances can be measured
  also
• After 2012, we will have a new generation of
  instrumentation allowing more and more accurate
  abundance measurements