Searching for emission from the warm-hot intergalactic medium
Yoh Takei (ISAS/JAXA) Takaya Ohashi1, Kosuke Sato2,3, Ikuyuki Mitsuishi4, Enzo Branchini5, Eugenio Ursino5, Alessandra Corsi6
1: Tokyo Metropolitan U.; 2: Kanazawa U.; 3: MIT; 4: ISAS/JAXA; 5: Roma Tre U.; 6: INAF-IASF-Rome Evolution of the Universe
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7 Warm-hot intergalactic medium
• Warm-hot intergalactic medium (WHIM): 5 7 • T=10 -10 K; 100 Mpc/h -5 -3 -3 nH = 10 -10 cm .
• Dominant baryon and metal reservoir at z=0.
• Chemical enrichment history is imprinted.
Cen & Ostriker 2006
Yoh Takei ([email protected]) COSPAR2010WHIM distribution(Bremen, 24 fromJuly, 2010)simulation 3 WHIM as a reservoir of baryons
Mass fraction Metal mass fraction WHIM
WHIM
Cen & Chisari 2010
Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 4 “Cooler” WHIM has been detected
• ~20% of baryons are in the cooler (<106 K) WHIM. • Though OVI and broad Ly! absorption lines in UV band. • Remaining ~40% baryons is “hotter” (>106 K) WHIM. • Could be detected in X-rays.
Baryons Compiled by M. Shull
WHIM “missing” 4.6% (BLAs) ~40% 14% 22.7% Dark matter WHIM 7% (OVI+BLAs) 8% galaxies Dark energy ~20% Ly! Forest clusters ~3% 30% 72.7% WHIM (OVI) cold HI <1% Further Reading: YohOVI: Takei Danforth ([email protected] & Shull 2005, 2008; Tripp) et al. 2000,COSPAR2010 2008; Thom (Bremen,& Chen 2008a,b 24 July, 2010) 5 BLAs: Richter et al. 2004, 2006; Lehner et al. 2007; Danforth, Stocke & Shull 2010 Ly! Forest: Penton, Stocke & Shull 2000-2004; Danforth & Shull 2006, 2008 WHIM observed in X-rays so far (1) 1352 BUOTE ET AL. Vol. 695 • WHIM associated with Sculptor Wall and RGS2. But due to the failure of one of the CCD chips early in the mission, the RGS2 lacks sensitivity over the energy range • Buote+2009, Fang+2010 (20–24 Å) relevant for the O vii lines. Consequently, we focus on the RGS1 in this paper. We analyzed the RGS1 data with • Redshifted OVII absorption line observed the most up-to-date XMM-Newton Science Analysis Software (SAS 8.0.0)6 along with the latest calibration files. with 4" significance. We generated a light curve of the background events using CCD number 9; i.e., the CCD that is close to the optical axis No. 2, 2010 CONFIRMATION OF X-RAY ABSORPTION BY WHIM• Detected IN THE SCULPTOR by both Chandra WALL and XMM 1719 and is most likely to be affected by the background flares. Inspection of the light curve does reveal a flare near the end of the observation, which we removed, resulting in a clean exposure of 126 ks for the RGS1. Using these good time intervals, we reprocessed the RGS1 data to produce the data files required for spectral analysis; i.e., the response matrix, the background spectrum, and the file containing the spectrum of H 2356-309 (which also contains background). We restrict our analysis to the first-order spectra, because the second order does not cover the relevant O vii line energies and its count rate is much lower. Chandra observed H 2356-309 for 95.5 ks with the Low- Energy Transmission Grating (LETG) and the HRC-S detectors, which offer the best compromise between sensitivity and spec- tral resolution in the wavelength range of the O vii lines. We reduced the data using the standard Chandra Interactive Analy- sis of Observations (CIAO) software (version 4.0) and Chandra Calibration Database (CALDB, version 3.4.0) and followed the standard Chandra data reduction threads.7 To ensure up-to-date Sculptor Wall calibration, we reprocessed the data from the “level 1” events Fang+ 2010 file to create a new “level 2” file for analysis. We applied the latest HRC gain map and pulse-height filter for use with LETG data.8 This procedure removed a sizable portion of background Buote+ 2009 events with negligible X-ray event loss. From inspection of the Figure 1. Sky map (top) and wedge diagram (bottom), each expressed in R.A., light curves extracted from source-free regions of the detector, Figure 4. Stacked Chandra data and best-fitting model as in Figure 3 except of the region of the Sculptor Wall where the blazar H 2356-309 is located. we concluded that the observation was not affected significantly shownYoh for Takei a wider ([email protected] wavelength range. We) omit theCOSPAR2010 corresponding (Bremen, expanded 24Galaxy July, redshifts2010) are taken from NED. The (blue) dashed lines in the upper6 Figure 3. Panel (a) shows the stacked spectra of the ten Chandra data sets, and panel define the range of declination of the galaxies displayed in the lower by background flares. RGS spectrum because much of the added bandwidth is contaminated by panel. Conversely, the (blue) dashed lines in the lower panel define the redshift We used the CIAO software to produce the files required panel (b) shows the XMM-Newton data set. The Chandra data were stacked using instrumental features. We caution the reader against interpreting uninteresting, range of the points in the upper panel. The blazar line of sight is indicated by for spectral analysis; i.e., the response matrix, the background the (red) dotted line in the wedge diagram. an adaptive binning scheme (see the text) intended for display purposes only. narrow, statistical fluctuations in the spectra as real features. The likelihood of spectrum, and the file containing the spectrum of H 2356-309 (A color version of this figure is available in the online journal.) The red lines are not produced by fitting the stacked spectrum, but rather are finding such a statistical fluctuation is dramatically enhanced if the line energy (which also contains background). Unlike the RGS, different the results of simultaneous fitting of the individual Chandra data sets (Figure 2) is not a priori known, in contrast to the case of the local and Sculptor wall orders cannot be separated from the LETG–HRC-S spectra, with the XMM-Newton data set. features we discuss in this paper. and so a given spectrum contains all orders. Consequently, by to catch the blazar in a high state. The observations were per- default we use a response matrix that includes information up (A color version of this figure is available in the online journal.) (A color version of this figure is available in the online journal.) formed four months apart because of different triggering criteria to the sixth order. In Section 3.5, we compare results using a used for the different satellites. response matrix that includes information only on the first-order Despite H 2356-309 being observed in its low state spectrum. that simply subtract a Gaussian from a continuum model. Note visual interpretation we stacked the individual spectra into a 11 2 1 ( 10− erg cm− s− 0.5–2.0 keV flux), we detected a can- We rebinned the spectra to optimize detection of the absorp- ∼ following B09, in calculating the optical depth we ignore the single combined spectrum using an adaptive binning scheme. didate WHIM O vii resonance line in the Sculptor Wall from a tion lines. After some experimentation, we achieved this by correction term from stimulated emission since it is negligible We show the resulting stacked spectrum for the Chandra data in simultaneous fit of the XMM and Chandra data. Although we requiring a minimum of 75 and 40 counts per bin, respectively, at the gas temperature where the O vii ionization fraction examined other candidate lines from other parts of the spectra in the RGS1 and LETG spectra. Figure 3 (along with the XMM data), which can be considered a using all the XMM and Chandra data, here we present only the In Figure 2, we present the background-subtracted Chandra peaks. lightly smoothed spectrum constructed from some components results for the O vii line because only for it do we achieve a and XMM spectra (the background subtraction is achieved To determine the significance of the WHIM line at 22.25 Å, with a coarser bin scale. Also shown are the best-fitting models detection of at least 3σ significance. in the normal way in xspec via the “data” and “backgrnd” ∼ The paper is organized as follows. In Section 2, we present commands). Two candidate absorption lines in each detector we adopt the following procedure. We first fit the Galactic (i.e., obtained from the simultaneous fits to the individual exposures. the observations and describe the data preparation. The spectral are immediately apparent upon visual inspection. The line near local) line in addition to the local continuum (all modified by We re-iterate that the models displayed in Figure 3 are not fitted fitting, modeling approach, and systematic errors are discussed 21.6 Å corresponds to O vii for z 0, consistent with nearby = Galactic neutral hydrogen absorption), where, as noted above, to the stacked spectrum. In Figure 4, we show the expanded in Section 3. We present our conclusions in Section 4. WHIM in the Local Group or hot gas in the Milky Way. However, the other candidate line near 22.3 Å corresponds to O vii the latter is restricted to have power-law exponent consistent Chandra spectrum between 20.5 and 23.5 Å. for z 0.03, consistent with the redshift of the unvirialized with the 90% limits that were established by the broadband Visual inspection of Figure 3 reveals very clearly the presence 2. OBSERVATIONS ≈ fit. The redshift of the added line was restricted to match the of the WHIM line near 22.25 Å. This is confirmed by the On 2007 June 2 XMM observed H 2356-309 (ObsID structure in the Sculptor Wall (z 0.028–0.032; B09). We improvement in the spectral fits when adding the WHIM line. 0504370701) for approximately 130 ks with the Reflection Grat- 6 http://xmm.esac.esa.int/sas/8.0.0/ = ing Spectrometer (RGS) as the primary instrument. The RGS is 7 http://cxc.harvard.edu/ciao/threads/ then add the WHIM line, fit again, and the resulting C-statistic The C-statistic decreases by 14.1 (229 bins) when using only comprised of two nominally identical sets of gratings, the RGS1 8 http://cxc.harvard.edu/contrib/letg/GainFilter/ difference between this fit and the previous one (local continuum the Chandra data and decreases even more (20.4 for 271 bins) + the Galactic line) gives the significance of the WHIM line. when including the XMM data in the fits. The reduction in the For the Galactic line, we follow the same procedure by fitting C-statistic and the total number of bins are over twice that the WHIM line first and then adding the Galactic line, which reported in B09 using only the Cycle-8 Chandra data along we restrict to have z<0.0025. with the XMM data, and thus the statistical significance of the We have two choices for spectral fitting. One is to stack all line detection is now much larger. (We note that the measured the observations into one spectrum and combine the response line equivalent width of 26 mÅ (Table 2) is very close to, and and effective area file of each observation into one response consistent with, the value≈ of 30 mÅ obtained by B09.) file. This approach is advantageous for low signal-to-noise Following B09, we estimate the statistical significance of the spectra. However, due to the variation of each spectrum (both WHIM and local lines using Monte Carlo simulations (see B09 power-law index and flux), which is typical for blazars, this for details). Briefly, we make two sets of simulated spectra for approach will produce significant systematic errors, as described each observation. One includes both source and background, in Rasmussen et al. (2007). So instead of stacking all the spectra, and one is the background only. For the simulated background we simultaneously fit all the data sets, such as we did previously spectra, we used the model parameters obtained by fitting the with the Cycle-8 Chandra data and the XMM data in B09. real extracted background with a single power-law model. For Each spectrum has its own RMF and ARF. While we allow the source spectrum, we use a model that includes the continuum the continuum parameters (photon index and normalization) and only one absorption feature, i.e., we include the Galactic to vary separately for each observation, the parameters for the line when estimating the significance for the WHIM line, and absorption lines are tied between each Chandra observation. We vice versa. We treat the two spectra in exactly the same way also allow the redshift of the XMM data to be fitted separately as the real data sets. In particular, as above we restricted the from the Chandra data, which we discuss more below. redshift of the WHIM line to lie between 0.028–0.032 to match In Figure 2, we display for each Chandra spectrum the best- the Sculptor Wall. fitting model obtained from a simultaneous fit of the Chandra First, we examined the significance of the Sculptor O vii line and XMM data. Because the absorption lines are not immediately using only the Chandra data. In 100,000 simulations of the apparent to visual inspection in every Chandra spectrum, to aid Chandra data without the Sculptor line, we obtained 64 false 5.3. EMISSION LINES IN THE EPIC SPECTRA 65
5.3.2 Spectral analysis We fitted the net vignetting corrected spectrum with a collisionally ionized thermal plasma model component (APEC in XSPEC) for the Coma hot gas, plus an APEC component for WHIMthe Milky observed Way background, plus in a power X-rays law component so for thefar cosmic (2) X-ray background. • SimilarThe strategy, free and fixedbut less parameters significant of the modelsreports are for given Virgo in Table and 5.7.Coma The clusters energy range for the spectral fit was 0.4-7.0 keV, excluding the834 energies of strong detector lines (1.4–1.6 keV). TAKEI ET AL. Vol. 655 • 2" OVIIIOur absorption key finding is for a clear Virgo detection of O VII and Ne IX lines from the X Comae field, as (Fujimoto,shown in FigureYT+ 2004) 5.9. In that figure we plot the ratio ofYT+ the 2007 data to the smooth continuum fit described above. We tried to fit the excess of the spectrum by adding anotherX Comae lower • 2.7temperature" NeIX absorption APEC model. for Coma However, the Ne IX line was not fitted, while O VII and O VIII (YT+structures 2007) were fitted. Next, we set the abundance of the warm thermal plasma zero and • Possibleadded three excess Gaussian emission lines to lines. represent O VII,OVIII and Ne IX lines. The width of the three Gaussians were fixed to be 1 eV, which is far smaller than energy resolution of the (redshift not constrained) detector. This model well fitted the data. The best fit values for the entire X Comae field No. ]are shown in Table Warm-Hot 5.7. Intergalactic Medium around the Virgo Cluster3
the best-fit C-statisticYT+ 2007 ofVicinity 177.43. of Thus, X Comae the improvement, Fujimoto, YT+ 2004 ∆C,is4.33.Thevalueof∆C approximately follows the χ2 statistic for 1 degree of freedom if the absorption line is just a statistical fluctuation (Cash 1979). In order to evaluate the statistical confidence of the line detection, we produced 10000 simulation spectra using the contin-
OVIII at Virgo z uum model shown in table 2 and the background without Possible Possible the absorption line. We then fitted the spectra with and Fig. 4.—Error-weighted average ratio of the data to the continuum model (as
without a Gaussian absorption or emission NeIX extratalactic line model.defined in eq. [1]) vs. z for the Ne ix and O viii lines. Vertical dashed lines in- dicate zComa and zComa 2:5gal. The two horizontal lines show the 1 error We obtained ∆C ≥ 4.33 for 3.6% of the simulation spec- Æ Æ
Galactic of the model continuum normalization with power-law indices fixed at their best- tra. This is consistentOVII/OVIII with the value expected from thefit values. The average of the ratio in the six bins between the left and right vertical χ2 distribution (3.7%). We thus conclude that the chancelines is 0:813 0:050. The significance of this absorption is 99.7% according Æ probability for detecting such an absorption line at theto Monte Carlosimulations. The average of theremaining 10continuumbins is 0:993 0:039, which is consistent with unity. The FWHM averaged wavelength very wavelength corresponding to O VIII Kα at the clusterresolutionÆ of RGS is also shown as a horizontal line at the lower right. Yoh Takei ([email protected]) COSPAR2010 (Bremen,redshift 24 July, is 3.6%; 2010) in other words, the statistical confidence7 of the absorption line is 96.4%. Figure 5.9: EPIC pn spectrum from the sum of the five regions around X Comae. Left: Fig. 2. Spectra around the O VIII Kα line obtained with The width of the wavelength range where both thethe absorption in our observed RGS data can be estimated as RGS1 and 2. Thethe cross spectrum and circle with symbols a model represent without the data metals. TheRGS1 discrepancy and 2 operate around is ∼ 0.5715.6 keVA.˚ Because and 0.90 the keV wavelengththe probability that the simulated spectra without absorption yield a smaller discrepancy from unity. The significance for the points of RGS1suggests and 2, respectively. the existence The thick of O andVII thinand solid Ne IX, respectively.resolution is ∼ Right:0.06 A,˚ the there ratio are of the about data 260 to independent a histograms show the best-fit models for RGS1 and 2. The grand error-weighted average was 99.7%. We conclude that smooth continuum (the model shown in thewavelength left panel. bins. The The smooth probability line is a for fit detecting of three an emis- backgrounds were not subtracted, but were instead simulta- we have detected absorption by material associated with the ≥ neously fittednarrow with a constant width model. (much The less background than the levelsresolution)sion/absorption Gaussians to the structure residuals. of The∆C center4.33 of at thesome wave-Coma Cluster with a significance of 99.7%. This significance is are shown withlower-energy dotted curves. two For illustrative Gaussians purposes, are fixed chan- to O VIIlengthand O isVIII almostat unity zero redshift, with an expectedrespectively, occurrence and of 9.4.equivalent to 3.0 of a Gaussian distribution. The significance nels with flickeringthat pixels of the were higher-energy masked. Gaussian is fixed toWe Ne searchedIX at the for Coma such redshift. structures in the observed spectra,of Ne ix and O viii was 98.0% (2.3 )and94.1%(1.9), and actually found seven such structures other than thatrespectively. Table 2. Best-fit parameters of the absorption line. at 19.05 A.˚ However, none of them can be identified with The equivalent width (EW) of the absorption lines can be cal- any atomic emission/absorption line with a reasonable os-culated from the ratios as (1 ratio)ÁE,whereÁE is the energy We also investigated the spatial variability of the O VII,OVIII and Ne IX lines. We À dividedAbsorption the X Comae line field into five concentriccillator annuli strength approximately at z =0,theclusterredshift,orthequasar centered on the center corresponding to the width of six bins we used to calculate the +0.8 redshift. Thus, these are all considered to be statisticalratios. The EWs for the four lines are also shown in Table 4. Energyof the 650 cluster.9 . (seeeV Figure 5.8 right), and fitted the spectra extracted from each region in the −1 9 fluctuations, and only the 19.05 Afeaturecanberealat˚ Assuming that the absorption lines are not saturated, the column Width (σ)* same< way.5.1eV(90%) The spectra of the four background fields were also fitted. Figure 5.10 shows the . astatisticalconfidenceof96.4%. density Nion is calculated from EW as (Sarazin 1989) Normalization (3.9+2 0) × 10−6 photons cm−2 s−1 surface brightness−2.8 of O VII ,OVII and Ne IX vs.We the then radius investigated from NGC4874. the systematic The five errors. points First, we Power law mec 1 z EW with a small radius corresponds to the X Comaechecked fields. the The RGS intensity spectra of the of bright Ne IX component X-ray sources in the Nion ðÞþ ; 2 ¼ he 2 f ð Þ Indexincreases 3.2 toward the Coma cluster center. Thearchival intensity data of to this ensure line in that the there background is no instrumental fields fea- os † ± × −4 Fig. 3.—Ratios of the data to the continuum model (as defined in eq. [1]) vs. Normalization (3.57 0.35) 10 ture at that wavelength. Then, since the estimation ofor C-statistic 177.02 z for Ne ix,Nex,Ovii,andOviii ( from top to bottom). Vertical dashed lines indicateanzComa absorptionand zComa line2:5gal could. The average be influenced RGS1 and RGS2 by the instrumental determina- Æ d.o.f 167 resolutiontion of 0.067 of the8 ( FWHM continuum, ) corresponds we to examined a redshift resolution the dependence of 0.0050, of 15 2 1 z EW ∗ For all fits except for the determination of the statistical error0.0055, 0.0031, and 0.0035 ( from top to bottom), which is indicated as a hori- Nion 9:11 ; 10 cmÀ ðÞþ ; 3 ¼ fos 1eV ð Þ for this parameter, it was fixed at 0.1 eV. zontalthe line at equivalent the lower right width of each on panel. the wavelength region used in the † In units of photons keV−1 cm−2 s−1 at 1 keV. fits and the choice of the continuum model. For this pur- ÀÁ pose, we changed the width of the wavelength bandTABLE for4 fits from 1.0 to 2.8 Aandaddedafifth-orderpolynomial˚ Ratio for Continuum and Absorption Spectral Regions compared with the detector resolution (∆λ ∼ 0.06–0.07 A˚ to the continuum. We found that, as long as the width of or ∆E ∼ 2eVFWHM).Whenwecalculatedtheerrors the fitting region is wider than 1.6 A,˚ the variation of the EW c a a,b of the absorption-line parameters, we also fixed the pho- equivalent width is smallerLine than 0.2 eV. When Continuumthe fitting Region Absorption Region (eV) ton index of the power-law component. The observed line . region is tooNe narrow,ix...... the continuum level is not well 1.027 con-0.058 0.782 0.071 (98.0%) 3.3 1.8 +0 8 Æ Æ Æ center energy and equivalent width were 650.9−1.9 eV and strained, andNe isx...... strongly coupled to the equivalent 1.011 width0.073 0.950 0.092 (42.7%) 0.8 (<3.9) +1.3 Æ Æ 2.8 . eV, respectively. If we assume that this is an O VIII of the line. O vii ...... 0.908 0.080 0.927 0.103 (50.0%) 0.7 (<2.6) −2 0 Æ Æ O viii...... 0.963 0.054 0.845 0.071 (94.1%) 1.7 1.3 absorption line, the energy shift from the rest frame is Assuming that the absorption line is not saturated,Æ the Æ Æ +0.8 +881 −1 Average of Ne ix and O viii ...... 0.993 0.039 0.813 0.050 (99.7%) ... 2.7−1.9 eV, which corresponds to cz =1253−369 km s . equivalent width is related to the ion column densityÆ in Æ −1 This is consistent with that of M87 (cz =1307kms ). the following way:a Errors are quoted at 68% confidence level. b Note that the systematic error in the absolute energy scale 2 Probability that a simulated spectrum without absorption yields a smaller discrepancy from unity. πhe c ErrorsNion are quoted at 90% confidence level, while upper limits are 2 . of the RGS is 8 mA(rms)or0.3eVat650eV(denHerder˚ EW = fos , (1) m c 1+z et al. 2001), which is much smaller than the statistical er- e rors. where Nion is the column density of the ion and fos is the We evaluated the statistical significance of the absorp- oscillator strength of the transition (Sarazin 1989). We tion line in the following way. The best-fit model without used fos =0.70 for the O VII resonance absorption line and an absorption line gives a C-statistic of 181.76. When fos =0.42 for that of O VIII (Verner et al. 1996). Then, +3.3 16 −2 we include an absorption line, but fix the center and the the O VIII column density was (6.2−4.4)×10 cm ,while width to the energy of the O VIII Kα resonant line with the 99.7% upper limit on the O VII column density was cz =1307kms−1 and σ =0.1eV,respectively,weobtain 3.7 × 1016 cm−2. WHIM observed in X-rays so far (3)
• Bridge between A222 and A223 (Werner+ 2008) • Explained by 0.9 keVN. Wernergas with et al.:overdensity Detection of (# hot/<# gas>) of in the~150. filament connecting the clusters of galaxies Abell 222 and Abell 223 L31
Yoh Takei ([email protected]+ 2008 ) COSPAR2010 (Bremen, 24 July, 2010) Fig. 2. The8 spectrum of the filament between the clusters A 222/223 –thedatapointsonthetopwereobtainedbyEPIC/pn and below by Fig. 1. Wavelet-decomposed 0.5–2.0 keV image of Abell 222 (to the EPIC/MOS. The contributions from the X-ray background and from South) and Abell 223 (the two X-ray peaks to the North). We show the filament to the total model are shown separately. only sources with >5σ detection, but for these sources we follow the emission down to 3σ.Thefilamentconnectingthetwomassiveclusters is clearly visible in the image. The regions used to extract the filament spectrum and to determine the background parameters are indicated by red and yellow circles, respectively. To verify our result, we created an image modelling the X-ray emission from the two clusters without a filament with two beta models determined by fitting the surface-brightness profile of A 222 and A 223. We then applied the wavelet-decomposition H radio data (N = 1.6 1020 cm 2, Kalberla et al. 2005). We H − algorithm to this image, which did not reveal a bridge such as modelled the background× with four components: the extragalac- that observed between A 222 and A 223. tic power-law (EPL), to account for the integrated emission of unresolved point sources (assuming a photon index Γ = 1.41 If the emission in the bridge between the clusters originated 11 1 2 2 in a group of galaxies within the filament, then this group would and a 0.3–10.0 keV flux of 2.2 10− erg s− cm− deg− af- ter extraction of point sources, De× Luca & Molendi 2004); two be well resolved in the image. Groups of galaxies at the red- shift of this cluster emit on spatial scales of 0.5 as shown in thermal components, to account for the local hot bubble (LHB) ≈ $ emission (kT = 0.08 keV) and for the Galactic halo (GH) emis- Fig. 1 by the six extended sources detected at the 4σ significance 1 around Abell 222/223 marked by ellipses numbered from 1 to 6. sion (kT2 0.2keV);andanadditionalpower-lawtoaccount for the contamination∼ from the residual soft proton particle back- The filament seen in the image is about 6$ wide, which at the ground. The best-fitted fluxes, temperatures, and photon indices redshift of the cluster corresponds to about 1.2 Mpc. of the background components, using the 3.2$ circular extraction The observed filament is about an order of magnitude fainter region, are shown in Table 1. than the ROSAT PSPC detected filament reported by Dietrich We modelled the spectrum of the filament with a et al. (2005). The ROSAT detection was based on an image collisionally-ionized plasma model (MEKAL), the metallicity of smoothed by a Gaussian with σ = 1.75$,andthefilamentcould which was set to 0.2 Solar (proto-Solar abundances by Lodders be the result of the combination of emission from the cluster 2003), which is the lowest value found in the outskirts of clus- outskirts and from a few previously unresolved point-sources be- ters and groups (Fujita et al. 2008; Buote et al. 2004). However, tween the clusters. since the average metallicity of the WHIM is unknown, we re- The point-sources (mostly AGNs) detected by port results also for metallicities of 0.0, 0.1, and 0.3 Solar. The XMM-Newton and Chandra do not show an overdensity free parameters in the fitted model are the temperature and the between the clusters, and the uniform contribution from the emission measure of the plasma. distant unresolved AGNs was subtracted from our image. Our 15 1 2 detection limit for point sources is 0.8 10− erg s− cm− , ∼ 41× 1 which corresponds to a luminosity of 10 erg s− for the faintest 3. Results resolved galaxy at the cluster redshift. The number of X-ray emitting galaxies with this luminosity required to account for 3.1. Imaging the observed emission in the filament would be 10 times larger ∼ We detect the filament in the wavelet-decomposed soft-band than expected from the distribution function of Hasinger (1998), assuming a filament over-density of ρ/ ρ 100. (0.5–2.0 keV) X-ray image with 5σ significance. In Fig. 1, & '∼ we show the wavelet-decomposed image produced by setting the detection threshold to 5σ and following the emission down 3.2. Spectroscopy to 3σ (for details of the wavelet decomposition technique see Vikhlinin et al. 1998). There is a clear bridge in the soft emis- The clusters of galaxies Abell 222 and Abell 223 are bright and sion between the clusters, which originates in an extended com- relatively hot. The temperature of A 222, extracted from a region ponent. We note that no such features are detected in any with a radius of 2$ is 4.43 0.11 keV and the temperature of XMM-Newton mosaics of empty fields in observations of sim- southern core of A 223 extractedwithin± the same radius is 5.31 ilar but also much larger depths. We do not detect the bridge 0.10 keV. However, we focus here on the bridge connecting the± between the clusters in the 2.0–7.5 keV image. two clusters. And several “unconfirmed” detection reports...
XMM warm Nicastro, F., Mathur, S., Elvis, M., Drake, J., component Fang, T., Fruscione, A., Krongold, Y., Mar- YT+ 2008 shall, H., Williams, R., & Zezas, A. 2005a, Na- • Kaastra+ 2003 (OVII/OVIIIture, 433, 495 emission associated withNicastro, clusters) F., Mathur, S., Elvis, M., Drake, J., Fiore, F., Fang, T., Fruscione, A., Krongold, Y., Marshall, H., & Williams, R. 2005b, ApJ, • Calibration and629, 700 Galactic foreground problem. Nicastro, F., Zezas, A., Drake, J., Elvis, M., Fiore, F., Fruscione, A., Marengo, M., Mathur, S., & Suzaku • Finoguenov+ 2003Bianchi, (OVII/OVIII S. 2002, ApJ, 573, emission 157 upper limits in Coma-11 field)Paerels, F., Rasmussen, A., Kahn, S., Herder, J. W., & Vries, C. 2003, X-ray Absorption • Solar wind chargeand Emission exchange Spectroscopy of the (YT+ Intergalactic Medium at Small Redshift 2008). Rasmussen, A., Kahn, S. M., & Paerels, F. 2003a, in ASSL Vol. 281: The IGM/Galaxy Connec- • Nicastro+ 2005 (OVIItion. The absorption Distribution of Baryons in the at z=0, ed. line of sight of Mrk421)J. L. Rosenberg & M. E. Putman, 109–+ Rasmussen, A., Kahn, S. M., Paerels, F., den • Not confirmedHerder, by J., XMM & de Vries, (Rasmussen C. 2003b, AAS/High + 2007, Kaastra+Energy Astrophysics2007). Division, 7, #201 Ravasio, M., Tagliaferri, G., Pollock, A. M. T., Ghisellini, G., & Tavecchio, F. 2005, A&A, 438, 481 Savage, B. D., Wakker, B. P., Fox, A. J., & Sem- Rasmussen+ 2007 Fig. 4.— A comparison of the 955 ks absorption bach, K. R. 2005, ApJ, 619, 863 Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010)spectrum toward Mrk 421 to the absorption line9 Schmidt, M., Beiersdorfer, P., Chen, H., Thorn, pattern of the Chandra LETGS spectrum (Nicas- D. B., Tr¨abert, E., & Behar, E. 2004, ApJ, 604, tro et al. 2005b; Williams et al. 2005). 562 Ulrich, M.-H., Kinman, T. D., Lynds, C. R., Rieke, G. H., & Ekers, R. D. 1975, ApJ, 198, 261 Williams, R. J., Mathur, S., Nicastro, F., & Elvis, M. 2006, ApJ, accepted for publication Williams, R. J., Mathur, S., Nicastro, F., Elvis, M., Drake, J. J., Fang, T., Fiore, F., Krongold, Y., Wang, Q. D., & Yao, Y. 2005, ApJ, 631, 856
This 2-column preprint was prepared with the AAS LATEX macros v5.2.
14 Lessons learned from “unconfirmed” detection
• Significant detections are only those associated with densest parts in large scale structures. • Random search of absorption lines have not resulted in a significant detection.
• Understanding possible systematic uncertainties is essential. • Detector background and response. • Galactic foreground emission. • Spatial variation of OVII/OVIII emission (Yoshino+ 2009) • Variability due to solar-wind charge exchange emission (Fujimoto+ 2007)
Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 10 Why do we search in emission?
Yoshikawa+ 2002 • Emission may give Dark matter Clusters us 3D distribution of the WHIM. • Absorption can only do pencil beam analysis.
• Interaction to dense nodes (clusters) may be studied. Galaxies WHIM
• However, applicable for only dense region 2 (I ∝ nH ) • Absorption can probe less density region (EW ∝ nH) 20 Mpc/h Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 11 Search for WHIM in emission
• Two approaches • CCD-based search using a current mission. • Search for redshifted OVII and OVIII lines to get “evidence” of WHIM. • Suzaku XIS used because it has low and stable detector background and line spread function at low energy is good. • Utilizing progress in understanding foreground emission.
• Proposing new mission with a microcalorimeter. • DIOS (Japan), XENIA (US, Europe, Japan) • Estimating detectability is important.
Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 12 Search cluster vicinities with Suzaku
Coma11 • Eight clusters and superclusters ROSAT R45 map A1413 have been observed. A2142 A2052 • Targets are selected based A2218 Shapley on the possible elongation in LOS and reported soft emission in literature. • Additional observations to determine the foreground A399/401 level are performed in most cases. Sculptor
Target Redshift Info Observation Reference
A2218 0.18 Elongation in LOS is suggested100 2005-10-27 YT+07 400 1400 Coma-11 0.02 XMM detected OVII/OVIII liens 2007-06-21 YT+08 A399/401 0.07 Pair cluster 2006-08-22 Fujita+08 A2052 0.04 Soft excess reported with XMM 2005-08-20 Tamura+08 A1413 0.14 Suzaku observed to virial radius 2005-11-15 Hoshino+10 A2142 0.09 Big cluster under merger 2007-01-05 Akamatsu+ in prep. Shapley 0.06 Soft excess reported with ROSAT 2008-07-10 Mitsuishi+ in prep. Sculptor 0.11 Soft excess reported with ROSAT 2005-12-03 Sato+ submitted Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 13 Spectra obtained with Suzaku
• Spectra are consistent with a sum of background and foreground emission, and hot intracluster medium in some cases.
Sculptor supercluster A2218 outskirts Sato, Kelley, YT+ (submtited) YT+ 2007
Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 14 Summary of search with Suzaku
• No detection. Tight upper limits of OVII/OVIII surface brightness is obtained.
• Some upper limits are tighter than previously claimed “detections”.
• Discrepancy mainly due to incorrect foreground modeling.
Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 15 Estimated upper limit of overdensity
I n n ZF(T )dL Suzaku sensitivity ∝ H e assuming Z= 0.1 Zsolar and L = 2 Mpc OVIII n2 ZLF (T ) 8 ∝ H Continuum 7.5 • Surface brightness is proportional to density2, abundance (Z), LOS path 7 length (L) and emissivity (F(T)). 6.5 • Density is constrained with an OVII assumption of Z, L and T. log T 6 T = 106 K • Suzaku upper limits correspond to 5.5 $~300 assuming Z = 0.1 Zsolar and L = 2 Mpc 5 $ = 300 • Note: in A222-223 filaiment, 4.5 $=150. -2 -1 0 1 2 3 4 log (density/mean baryon dnesity)
Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 16 Future missions optimized for WHIM study
XENIA DIOS (Japan) (US, Europe, Japan)
• % E: 2 eV • % E: 2.5 eV (goal 1 eV) • Effective area: ~100 cm2 • Effective area: ~1000 cm2 (goal 1300) • N of pixels: 12 x 12 pixels • N of pixels: 2000 (goal 2176) • FOV: 0.7 deg x 0.7 deg • FOV: 0.9 deg x 0.9 deg (goal 1 x 1) • PSF: 2 arcmin HPD • PSF: 4 arcmin HPD (goal 2.5)
Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 17 Simulation for detectability with XENIA
• Studied mock spectra based on SPH simulation by Borgani+ 2004, based on GADGET-2 (Springel+ 2005) • Spectrum is calculated assuming CIE. • Metallicity is determined a posteriori, min(0.3, 0.005(#/<#>) with scatter to reproduce Cen & Ostriker 1998). X–ray cluster properties 5
• !" = 0.7 • !b = 0.04 • h = 0.7 • #8 = 0.8 • Box size = 192h-1 Mpc • particles = 4803 + 4803 • Gravitatioal softning: $ = 7.5h-1 Mpc at z=0. • SF: included as sub- resolution multiphase mode (Springel & Hernquiet 2003) • FB from SNe: weak Gas density profile (Borgani+ 2004) galactic outflows 192 h-1 Mpc • Radiative cooling assumes zero metallicity FigureYoh 1. Left Takei panel: ([email protected] map of the gas density over the) whole simulationCOSPAR2010 box at z =0,projectedusingaray–tracingtechniquethrough (Bremen, 24 July, 2010) 18 aslicehavingthicknessof12 h−1Mpc, and containing the most massive cluster found in the simulation (upper right side of the panel). Right panel: zoom into the region of the largest cluster; the cluster is shown out to one virial radius, so that the panel encompasses a physical scale of about 4.5 h−1 Mpc.
pansion factor, from aexp =0.1toaexp = 1, thus producing the large dynamic range encompassed by the hydrodynamic a total amount of about 1.2 Tb of data. The fine spacing treatment of the gas in our simulation. of snapshots in time can be used to measure merger tree of The cluster shown in Fig. 1, which has an emission– halos, and to realize projections along the backward light– weighted temperature of Tew ! 7 keV (see below), is re- cone. solved with about 2 × 105 DM particles within the virial radius. Overall, we have 400 halos resolved with at least 10,000 DM particles, 72 clusters with Tew > 2keV,outof which 23 have Tew > 3 keV. Clusters with Tew =1keV 3 RESULTS are resolved with about 7,000 DM particles. Therefore, our We start our analysis with an identification of groups and simulation provides us with an unprecedented large sample clusters within the simulations box. To this end, we first of simulated groups and clusters of medium-to-low richness apply a friends-of-friends halo finder to the distribution of that are represented with good enough numerical resolution DM particles, with a linking length equal to 0.15 times their to obtain reliable estimates of X–ray observable quantities, mean separation. For each group of linked particles with such as luminosity, temperature and entropy. more than 500 members, we identify the particle having the In the following, we will mainly concentrate on the de- minimum value of the gravitational potential. This particle scription of the properties of clusters at z =0,whilewe is then used as a starting point to run a spherical over- will deserve to a forthcoming paper the discussion of the density algorithm, which determines the radius around the redshift evolution of the X–ray scaling relations and their target particle that encompasses an average density equal comparison with observational data. to the virial density for the adopted cosmological model, 2 ρvir(z)=∆c(z)ρc(z), where ρc(z)=[H(z)/H0] ρc,0 is the critical density at redshift z, and the overdensity ∆c(z)is 3.1 The stellar fraction in clusters computed as described in Eke, Cole & Frenk (1996). In the left panel of Figure 1, we show a map of the gas Observational determinations of the fraction of baryons distribution at z = 0, projected through a slice of thickness locked up in stars in galaxy clusters, f∗,consistentlyindi- 1/16th of the box size. This slice includes the most massive cate a rather small value. For instance, Balogh et al. (2001) cluster found in the simulation, which is located in the upper found this fraction to be below 10 per cent, independent of right region of the map. The panel on the right shows the the cluster richness. More recently, Lin et al. (2003) selected gas distribution of this cluster out to the virial radius, thus a sample of nearby clusters, with ICM masses available from representing a zoom-in by about a factor of 40. The tiny dark ROSAT-PSPC data and total stellar mass estimated from spots visible in the central cluster regions are condensations the total K–band luminosity, as provided by the 2MASS of high–density cold gas. They mark the locations where survey (e.g., Cole et al. 2001). They found that rich clus- < star formation is taking place and, therefore, the positions ters have f∗∼ 10 per cent, with an increasing trend toward of cluster galaxies. The amount of small–scale detail which poorer systems (see the data points plotted in Figure 2). is visible in the zoom–in of the right panel demonstrates On the other hand, hydrodynamical simulations of clus-
!c 2003 RAS, MNRAS 000,000–000 Detecting emission lines from mock spectra
• Created mock spectra for 0 Detector (CRIS) 2 10 Black: Galactic + CXB (z=0.033) (z=0.033) WHIM OVII WHIM OVIII Galactic OVII Galactic OVIII 2.6 arcmin ! Red: extragalactic diffuse in 2.6 1 -1 KeV -1 10-1 Counts sec –10 18-2 – -3 10 0.4 0.45 0.5 0.55 0.6 0.65 0.7 one can compute the significance of a line detection using the following expression: Energy (keV) fline σline = ∆ΩtexpAeff , (1) [fline +(fCXB + fFG)∆E] ! 12 eV 2.6’1 x 2.6’1 2 where fline is the line flux in! units of photons cm− s− sr− , ∆E1000is cm the (XENIA) energy resolution 20 ph s-1 cm-2 keV-1 sr-1 of theYoh instrument, Takei ([email protected]ff its effective) 30COSPAR2010 area, ph s-1 cm∆Ω-2 keVits (Bremen,-1 sr angular-1 24 July, resolution 2010)1 Ms and texp is the exposure19 time. Eq. 1 assumes that both signal and noise can be treated as Poisson variables. In Table 2 we list for the two WHIM model explored (column 1) and two different exposure times (col. 2) the minimum line surface brightness required for a 5σ line detection (col. 3) in a hypothetical observation performed with CRIS. The value should be revised after fixing the assumed FG and CXB level. The corresponding number of detections per resolution element and unit redshift can be obtained from the dN/dz statistics plotted in Figures 2, 3 and 4. They are listed in columns 4 (OVII), 5 (OVIIII) and 6 (simultaneous OVII and OVIII detections), respectively. Column 7 shows the total number of OVI+OVIII WHIM detections expected in the CRIS field of view due to the gas at z 0.5. Each entry in ≤ the table shows two values. The higher one represents the expected number of detected lines contributed by all gas, not just the WHIM, along the line of sight. The smaller one refers to lines which can be attributed to the WHIM. All detection estimates assume an angular resolution of 4 arcmin (i.e. the CRIS baseline) and thus are easily rescaled to the resolution of 2.5 arcmin (the CRIS goal). ¿From Table 2 we see that the expected number of WHIM detections is quite large even in the least favourble case (model B1, texp=100 ks, simultaneous OVII+OVIII detection), making us confident that next generation instruments will give us the possibility not only to detect the WHIM but also to investigate its statistical and physical properties. Long exposures of 1 Ms are required to trace the 3D distribution of the WHIM, as it will be shown in Section 5.2. In this case, the existence of a large scatter in the density-metallicity relation, like in our B2 model, is required to detect the WHIM away from the higher density peaks, i.e. to trace its filamentary structure. Observational perspectives for the study of the WHIM are actually even more promising since detections estimates estimates listed in Table 2 are likely to be biased low. For three reasons. First of all, we have considered only gas within z =0.5 while numerical simulations indicate that baryon mass fraction in WHIM does not drop suddenly beyond z =0.5. Instead it slowly decreases with redshift: it constitutes 30-40 % of the baryons at z = 1 and 18-20 % at z = 2 (Cen & Ostriker 2006). The hope is to be able to use metal lines different from OVII and OVIII to detect the WHIM atz>0.5 Second of all, we have considered the baseline characteristics of a detector like CRIS, while it is likely that next generation detector will be able to match some of the goal requirements. Finally, we have considered a XENIA 1 Ms detection limit Detectability with XENIA All gas WHIM ($ < 1000; • Expected detection is dNdz > 1 for 105 K < T < 107 K) both OVII and OVIII lines for a single sight line. • With 1 deg x 1 deg FOV, dz = 0.5, All gas WHIM and 2.6‘x2.6’ angular element size, ($ < 1000; More than 600 OVII/OVIII pairs are 105 K < T < 107 K) expected to be detected with one 1 Ms observation. WHIM+clusters +groups All gas WHIM ($ < 1000; 105 K < T < 107 K) Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 20 Identified gas in %-T plane 8 1.2 7.5 1 Log (T [K] 7 0.8 6.5 0.6 6 0.4 5.5 5 0.2 4.5 0 -2 -1 0 1 2 3 4 Log (! /< ! >) gas gas All gas > 105 K, averaged in 2.6’ x 2.6’x 3 Mpc Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 21 Identified gas in %-T plane 8 1.20.9 7.5 0.8 1 Log (T [K] Log (T [K]) 0.7 7 0.80.6 6.5 0.5 0.6 6 0.4 0.40.3 5.5 0.2 5 0.2 0.1 4.5 0 -2 -1 0 1 2 3 4 Log (! /< ! >) gas gas DetectedAll gas > 10 with5 K, 1Ms averaged exposure in 2.6’ x 2.6’x 3 Mpc Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 21 Mass fraction probed with emisison 0.5 • Most of $>100 and half 0.4Mass fraction of $>30 region can be probed with 1 Ms exposure of XENIA. 0.3 0.2 • With 100 ks, only $>100-300 can be 0.1 probed. 0 -2 -1 0 1 2 3 4 Log (! /< ! >) gas gas Red: detected with 1Ms exposure Blue: detected with 100 ks exposure Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 22 Expected 3D map at z=0.22 Gas density OVII/OVIII emission line 5.5 deg = 48 Mpc/h 54 Mpc/h (!z = 0.02) Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 23 Expected 3D map at z=0.1 Gas density OVII/OVIII emission line 5.5 deg = 23 Mpc/h 58 Mpc/h (!z = 0.02) Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 24 Prospects with other missions • Suzaku • Sensitivity reaches to $~300. Possibly we will get evidence of redshifted O lines for a few cluster outskirts • DIOS • Similar energy resolution, but x10 smaller effective DIOS area as XENIA. • Expected to provide similar 3D maps as XENIA. However, only denser nodes can be probed. • Astro-H (2014) • First microcalorimeter in orbit. But small effective area (100 cm2) and small FOV (2.9‘x2.9’) limits the study at cluster outskirts/groups. Astro-H • IXO • Quite larger effective area (x10), but small FOV (x1/1000). Good to probe smaller scale blobs, but IXO not suitable for mapping. For absorption study, IXO will provide a significant progress. Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 25 XENIA as a probe of chemical evolution Evolution of the Universe 1(00(#+(2.Small scale Past 3,+4) • Current Universe reflects !"# Stars GRBs $%&$'()$%& SNRs • not only structure :"";3(-7.8. formaiton by gravity, "&+$-<0"&)Starburst galaxies/ • but also chemical Galaxies *)+,-),+". AGNs /%+0()$%& enrichment and feedback from smaller scale to largr 56,4)"+.%,)47$+)4.8. scale. "9%6,)$%& Clusters Structure formation Structure Clusters ! !";4<$/) • The warm-hot intergalactic medium (WHIM) forms largest structures in the local =1>."0$44$%& Feedback & Enrichment Feedback Universe, tracing distribution =1>.(34%+?)$%& ! Present WHIM ! "#$%!&'(!)**+,!-./+012!13,4.5+!6,#$78/+11!#9.$+!4:,!.!;:19:0:$#5.0!1#930.8#:/!:4!.!50318+,!.8!.!,+<17#48!:4!=%=(! of dark matter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`1!"C'9:+&0+)/1+.!"'.+,0/+(!#*/0<*+#5+).8($#K'++*/!:"42+!280T*-&+#5#.+0$!+1,3-,:+0,21-!(&4:#,%!+"'*3('*"01+(+2+(8'3(0-+$)/&-"0*+ ")+ '0-#*+ (2+ %")0+ ")'0)*"'"0*+ &<&")*'+ =3"13+ =0+ /0-".0+ ($-+ #/<##K(#+I30)+0'+&%:+ 1T18+9.8#51!#/!87+!LCC'M+H8:/!+,,:,!63<$+8%!M:8+!7:H!:61+,-K0.8#:?/1$!+A"8-+/0&C'K"#(,E)!&+%2R(!$A!)R=/R+(8!C91+:I0[!0c):/+K5.+L,+0*0#!'+-8"!M.00%!-&A=H=NBN?!N! E+'3&'+")1%$/0+'30+ @72+0!0,+/<8! *&:1#/M8+!0#/2<20#51.'8+1(!28+7<+&! +%&A*1+'"518+<*!$5,:0/1-8O,=.#/")8!/.*8!+c&&)==/! H+/#870!,.&! ,-+'$0.-8#0K+*!++2-,,(:#,! :+4%!(B1d&!%+>R'3a0?D!-#:6(8./#/9+)<&! 4#,:9"1!+R0!?C$1"!%"8-"$#:+P"<$-0+ +AP*:"<13:+,+B!OHH#+87"%!%N$O*P'-N&%'!0M*:+8+'3!807.+,8!4-:(,1!80T*/#5$.-00!:+6=e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�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�)'*+=0-0+2(-#0/+:+6)+'3"*+-0*,01'+QR@*+&-0+'30+,0-201'+*($-10*:+5(=0.0->+'309+ 0#"'+&+1()*"/0-&8%0+2-&1'"()+(2+'30+*(2'+\O-&9+,3('()*+*(()+&2'0-+'30+,-(#,':+;30-02(-0>+2&*'+-0O,(")'")<+ 1&,&8"%"'"0*+&-0+-0?$"-0/+'(+0[,%("'+QR@*+&*+\O-&9+80&1()*:+ Q".0)+'30+2%$0)10+(2+&+QR@+'30+02201'".0+&-0&+&)/+*,01'-&%+-0*(%$'"()>+"'+"*+*'-&"<3'2(-=&-/+'(+1(#,$'0+ '30+#")"#$#+0?$".&%0)'+="/'3+^S4_+-0?$"-0/+'(+/0'01'+&+%")0+="'3+&+*"<)"2"1&)10+%&-<0-+'3&)+Y!++&)/+'30)>+ 2-(#+ #(/0%*>+ '30+ &.0-&<0+ )$#80-+ (2+ %")0*+ ,0-+ $)"'+ -0/*3"2'+ &8(.0+ '3&'+ <".0)+ S4:+ ;30+ /-(,+ ")+ '30+ )$#80-+(2+*9*'0#*+&8(.0+H`C+M#a*+A"C:Y+0FE+"#,%"0*+'3&'+()%9+#0/"$#+8-"<3'+&2'0-<%(=*>+="'3+&+2%$0)10+ b+C:`+M0F]+`+HCOG+1<*+="%%+80+02201'".0:+;3$*+'30+,-"#&-9+-0?$"-0#0)'+2(-+'30+STQS+4"/0+P"0%/+7()"'(-+ "*+ '(+ &13"0.0+ &+ %&-<0+ 2"0%/+ (2+ ."0=>+ ")+ (-/0-+ '(+ #&["#"U0+ '30+ )$#80-+ (2+ 8-"<3'+ &2'0-<%(=*>+ $*$&%%9+ 7 XENIA as a probe of chemical evolution Evolution of the Universe XENIA s keV 0.04 2 1(00(#+(2. − Small scale Galactic 0.02 Past 1000 2000 3,+4) Photons cm OVII GRBs • CurrentAbsorption in GRB at Universez=7 reflects r=15’ (Shock) Stars 1 r= 0’ (Center) !"# − Si S CVI NVI NVII OVII keV 1 $%&$'()$%& − CV OVIII Ratio Fe 0.80.9 1 • not only structure SNRs 0.2 0.5 1 Energy (keV) First metal creation at Counts s :"";3(-7.8. z>5 formaiton by gravity, 0 50 100 150 200 0.4 0.5 0.6 "&+$-<0"&)Starburst Absorption at z=1 Energy (keV) galaxies/ • but also chemical Galaxies Metal creation/injection *)+,-),+". AGNs by super novae /%+0()$%& enrichment and feedback from smaller scale to largr T / 56,4)"+.%,)47$+)4.8. scale. 0.4 0.6 0.8 1 1.2 Absorption in GRB host "9%6,)$%& 200 galaxies Clusters M / 0 0.5 1 0 0.5 1 Structure formation Structure Clusters r / R200 ! Cluster temperature/mass . O !";4<$/) • The warm-hot intergalactic study to virial radius Z / 0.3 medium (WHIM) forms Galactic +: Fe x: Si NeVII Counts 0largest 0.5 1 structures in the local 0 0.5 1 =1>."0$44$%& 1 10 1001000 Feedback & Enrichment Feedback r / R200 ClusterUniverse, abundance to tracing distributionOVII =1>.(34%+?)$%& OVIII z=0.069 ! virial radius OVII Present WHIM ! Counts "#$%!&'(!)**+,!-./+012!13,4.5+!6,#$78/+11!#9.$+!4:,!.!;:19:0:$#5.0!1#930.8#:/!:4!.!50318+,!.8!.!,+<17#48!:4!=%=(! of dark matter. OVIII z=0.30 >,+4%?%!@7+!1#930.8#:/!#1!&:A&:!5:,,+1*:/<#/$!8:!B%BC*5AB%BC*5D!87+!50318+,!7.1!,&==!E!!&%F!C*5D!*#A+01!.,+!(G!:/!87+! 1#<+%! @7+! 8H:! #9.$+1! 17:H! 87+! 13,4.5+! 6,#$78/+11! :4! 87+! 1#930.8+.6:38!R=!8#9+1!0:H+,?%!@7+!5#,50+1!7.K+!.! Missing baryons at low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`1!"C'9:+&0+)/1+.!"'.+,0/+(!#*/0<*+#5+).8($#K'++*/!:"42+!280T*-&+#5#.+0$!+1,3-,:+0,21-!(&4:#,%!+"'*3('*"01+(+2+(8'3(0-+$)/&-"0*+ ")+ '0-#*+ (2+ %")0+ ")'0)*"'"0*+ &<&")*'+ =3"13+ =0+ /0-".0+ ($-+ #/<##K(#+I30)+0'+&%:+ 1T18+9.8#51!#/!87+!LCC'M+H8:/!+,,:,!63<$+8%!M:8+!7:H!:61+,-K0.8#:?/1$!+A"8-+/0&C'K"#(,E)!&+%2R(!$A!)R=/R+(8!C91+:I0[!0c):/+K5.+L,+0*0#!'+-8"!M.00%!-&A=H=NBN?!N! E+'3&'+")1%$/0+'30+ @72+0!0,+/<8! *&:1#/M8+!0#/2<20#51.'8+1(!28+7<+&! +%&A*1+'"518+<*!$5,:0/1-8O,=.#/")8!/.*8!+c&&)==/! H+/#870!,.&! ,-+'$0.-8#0K+*!++2-,,(:#,! :+4%!(B1d&!%+>R'3a0?D!-#:6(8./#/9+)<&! 4#,:9"1!+R0!?C$1"!%"8-"$#:+P"<$-0+ +AP*:"<13:+,+B!OHH#+87"%!%N$O*P'-N&%'!0M*:+8+'3!807.+,8!4-:(,1!80T*/#5$.-00!:+6=e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�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�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`C+M#a*+A"C:Y+0FE+"#,%"0*+'3&'+()%9+#0/"$#+8-"<3'+&2'0-<%(=*>+="'3+&+2%$0)10+ b+C:`+M0F]+`+HCOG+1<*+="%%+80+02201'".0:+;3$*+'30+,-"#&-9+-0?$"-0#0)'+2(-+'30+STQS+4"/0+P"0%/+7()"'(-+ "*+ '(+ &13"0.0+ &+ %&-<0+ 2"0%/+ (2+ ."0=>+ ")+ (-/0-+ '(+ #&["#"U0+ '30+ )$#80-+ (2+ 8-"<3'+ &2'0-<%(=*>+ $*$&%%9+ 7 Summary • WHIM study using emission still remains to be done. • No significant detection yet. • Will be a new probe for cosmic chemical evolution. • XENIA will certainly make a remarkable progress. • ~600 OVII/OVIII pairs in a 1 Ms exposure. • Half of mass of $~30 detected. • 3D maps. • CCD-based analysis (Suzaku) is quite tough, but maybe detect a few redshifted O lines associated with the large scale structure. Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 27 Energy budget on a dish Baryons (pepper and sauce) Dark energy Dark (beef) matter (potato) Yoh Takei ([email protected]) COSPAR2010 (Bremen, 24 July, 2010) 28