The XMM-Newton (and multiwavelength) view of the nonthermal supernova remnant HESS J- Gerd Pühlhofer Institut für Astronomie und Astrophysik Kepler Center for Astro and Particle Physics Tübingen, Germany V. Doroshenko, G. Pühlhofer, A. Bamba, F. Acero, W. W. Tian, D. Klochkov, A. Santangelo
The search for hadronic SNRs Several historic SNRs have been advocated in the last years to be hadronic SNRs (hadronic = γ-ray emission dominated by π 0 decay) Examples: IC, W, WB, WC, Tycho, Cas A Mostly based on π 0 -bump detected with Fermi-LAT Interaction with molecular clouds Young and middle-aged SNRs TeV emission of these sources (if detected and identified as SNR emission) mostly unresolved or marginally resolved GeV-dominated (in the γ-ray band), hard to track the highest energy particles (if present) TeV image of Tycho s SNR VERITAS coll. π 0 bump XMM-Newton view of the SNR HESS J- - 2 - X-ray Universe, Rome, June 6-
Resolved shell-type supernova remnants in the TeV band RX J.-6 roughly to scale RCW 6 Young, resolved (in TeV), TeV-dominated (in γ-rays) Strong X-ray synchrotron emission, correlated with TeV just leptonically dominated? SN06
HESS J- Similar TeV luminosity as RX J.-6 First discovered in TeV γ-rays; SNR nature through radio synchrotron shell Object not discovered in ROSAT survey (fainter + stronger absorption compared to RX J.-6) Before this work, partial coverage with XMM- Newton + Suzaku pure nonthermal X-rays SED similar to RX J.-6 leptonic? New: complete XMM-Newton coverage of the source H.E.S.S. coll., A&A () HESS J- G.6-0. Observation Observation Duration, Exposure ID Date ks (M/M2/PN), ks 0060 0-0-2 2. 22./22./2. 060 2-0-02 2. 2./2./0 0600-0-0 2.././2. 020 --0 6.././.6 02-02-2.2././0 total: 2.2/2./6.2 XMM-Newton view of the SNR HESS J- - - X-ray Universe, Rome, June 6-
XMM-Newton complete coverage E N Questions (to this data set): Distance estimate to the source Co-location with gas/molecular clouds? Photon index variations? SNR/density geometry? Absorption column X-ray surface brightness? -.0 -. -.6 -. 26. 26.2 26.0 262. 262.6 Scutum-Crux arm ~ kpc Norma-Cyg arm ~. kpc kpc arm ~-6 kpc LOS After HESS coll., A&A XMM-Newton view of the SNR HESS J- - - X-ray Universe, Rome, June 6-
XMM-Newton complete coverage E N Strong contamination by stray light from nearby LMXB Exclude most heavily contaminated regions and treat residual stray-light as additional background component -.0 -. -.6 -. Residual soft proton/qpb and astrophysical background (GRXE) further complicate the analysis (different in different observations) 26. 26.2 26.0 262. 262.6 For spatially resolved analysis fit all spectra simultaneously: No evidence for thermal emission No signifiant variation of the power-law index mainly probe N H variations with fixed power law index Γ Image: observed flux, corrected for all identified backgrounds, including (a large fraction of) straylight XMM-Newton view of the SNR HESS J- - 6 - X-ray Universe, Rome, June 6-
Fit: residual stray light component Fit spectra simultaneously to single-out the background (stray light, QPB, soft protons, GRXE for obs, 2 regions, instruments, but not all regions covered by all combinations), all linked in a complex way with each other to reduce the number of free parameters. 0 6 2 2 6 exposure 2 surface brightness residual stray light constant Γ assumed 0.0 0.2 0. 0.6 0..0.2..6. 2.0 XMM-Newton view of the SNR HESS J- - - X-ray Universe, Rome, June 6-
Fit: residual stray light component Fit spectra simultaneously to single-out the background (stray light, QPB, soft protons, GRXE for obs, 2 regions, instruments, but not all regions covered by all combinations), all linked in a complex way with each other to reduce the number of free parameters. 0 6 2 2 6 exposure 2 Example spectrum (region 2) XMM-Newton view of the SNR HESS J- - - X-ray Universe, Rome, June 6-
Main results: surface brightness and N H Intrinsic (deabsorbed) surface brightness Absorption column 0 6 2 2 6 2 0 6 2 2 6 2 Fig. 2. Intrinsic X-ray flux variation: drop towards West XMM-Newton view of the SNR HESS J- - - X-ray Universe, Rome, June 6-
Lower limit on distance (renewed) X-ray absorption Gas column density (to.2 kpc) 6 0 2 6 2 2 can correlate N H map with CO map H.E.S.S. coll., A&A () XMM-Newton view of the SNR HESS J- - - X-ray Universe, Rome, June 6-
Lower limit on distance (renewed) Correlation between N H and gas map for different distances image from H.E.S.S. coll., A&A () 0.0 realisations with r > robs,%.0.0 0. 0 0 60 0 0 υ LSR,min Quantitative correlation analysis independently confirms the distance lower limit of ~.2 kpc g.. :cumulativeabsorbingcolumndensity(solidline)asafun XMM-Newton view of the SNR HESS J- - - X-ray Universe, Rome, June 6-
Optical extinction Red: optical (VISTA, VVV survey) extinction map, resolution; Green: ATLASGAL 0. mm..0 NH, 22 cm 2 2. 2.0..0 0. 0.0 0..0. 2.0 2..0. A V,rel ig.. Correlation of the absorption column measured from the spatially resolved spectral analysis of XMM-Newton data and the relative Optical extinction is well correlated with X-ray absorption independent check of validity of X-ray analysis alignment with other gas tracers and SNR boundary in the N-W XMM-Newton view of the SNR HESS J- - 2 - X-ray Universe, Rome, June 6-
Morphological correspondence shell-gas? Blue: X-rays; Green: radio synchrotron; Red (+contours): Herschel SPIRE 0 µm Red: optical (VISTA, VVV survey) extinction map, resolution; Green: ATLASGAL 0. mm..0 NH, 22 cm 2 2. 2.0..0 0. 0.0 0..0. 2.0 2..0. A V,rel ig.. Correlation of the absorption column measured from the spatially resolved spectral analysis of XMM-Newton data and the relative Apparent correspondence of gas tracers with SNR boundary in the N-W suggests co-location and interaction of SNR and molecular cloud at.2 kpc XMM-Newton view of the SNR HESS J- - - X-ray Universe, Rome, June 6-
Spectral energy distribution Updated SED: no scaling due to partial coverage necessary any more SED parameters not much affected wrt. earlier analyses Favours leptonic interpretation (?) E 2 dn/de [erg s cm 2 ] 2 6 Energy [ev] Fig.. Broadband spectral energy distribution and the best-fit leptonic scenario model. The X-ray spectrum used here is a simulated PN spectrum with exposure adjusted to yield the same spectral index and flux uncertainties as the best-fit result presented in Table 2 (i.e. the flux is integrated over all extraction regions with contribution of point sources removed). XMM-Newton view of the SNR HESS J- - - X-ray Universe, Rome, June 6-
..(2).(2) 2.(2) 2..6(6) 0.0(0) 0.() V. Doroshenko et al.: XMM-Newton observations of the non-thermal supernova remnant HESS J (G.6-0.) al.: XMM-Newton of the non-thermal supernova remnant HESS J (G.6-0.) V. Doroshenko 22. et.(2).0() observations 0.6() 66..2().(2) 0.00() 6 0..(2) 2.() 0.00() 2..().() 0.00() 6 0 0 2..(2).2() 0.6() 0 2 0 0 2 2 2 2..().2() 2.() 2 2.2.() 0.0(2) 2.() 6..(2).() 0.06().02(). 2.(2).6() 6 6 6 6..2(2).0(2) 2.(2) 6 6 6.0.() 0.0().(2) Fig.. The X-ray image screened for point source and corre 6 6 contribution 6 6 2. 6.().().22() the intrinsic source flux (left panel). The bright blob in the centre of the X 2 2 2 2 2.() 2 2 radio (red, GMRT), X-ray 2(green, XM 2 2 2 60..(2) 2.(2) of the SNR shell morphology in Asymmetry panels. Note that the bright radio and X-ray filaments seem to be well Table 2. Spectral extraction region parameters and best fit results as- and extends further towards the Galactic plane. There seems to be a corr suming pure power-law with constant index for all regions. a arcmin2, contour) tracing the cold dense region also noted by Maxted et al. () b atoms cm 2, c 2 erg cm 2 s arcmin 2 with a 0.06 Gaussian, corresponding to the PSF of the HESS data. Note radio (red, GMRT), X-ray (green, XMM), TeV (blue, H.E.S.S.) Fig.. The X-ray image screened for point source contribution and corrected for the identified background components and absorption represents sub-mm Fig. 2. Left panel shows the mosaic pseudo colour yellow image incontours: 0.-. kev (red),.-2. kev (green), and 2.- kev (blue) energy bands corrected emission flat thetev intrinsic source fluxazimuthally (left panel). The bright blob in the centre of the X-ray shell is due to residual emission from the bright CCO. A comparison for particle, soft proton, and residual stray light contamination. The definition of regions. used for spectral analysis is also shown. The middle panel of the SNR shell morphology in radio (red, GMRT), X-ray (green, XMM-Newton) and TeV (blue, HESS) bands as shown in middle and right shows the combined exposure map in 0.- kev band where regions most heavily contaminated by stray light and excluded from the analysis can panels. X-rays E-W asymmetry Noteshow that the strong bright radio and X-ray filaments seem to be well correlated (middle panel). However, the radio shell is more symmetric be identified. The right panel shows the derived absorption column density (linear scale in range NH 22 atoms cm2 ). and extends further towards the Galactic plane. There seems to be a correspondence between the continuum radio and sub-mm emission (yellow picture for γ-rays? Possibilities:.0 contour) Leptonic tracing the cold dense region also noted by Maxted et al. () in the CS MOPRA data. The right panel shows all three bands smoothed a 0.06 2Gaussian, corresponding to the PSF of the HESS data. Note the region at l., b 0. where the shell is only bright in TeV. e vari-with Inverse Compton in the West enhanced by in the 0. higher target photon field e and hind of the molecular cloud at the same time. This can be either. hoton if the apparent alignment is still a chance coincidence, or if the e rep- Lower B-field and higher electron density 0.0 remnant and the molecular cloud responsible for the absorption hoton inthe West.0 to the of the observed X-ray emission are actually at the same distance Or: additional hadronic component? g and kage 6 0. Consistent with gas in the West if SNR is indeed co-located with gas 0.0 Energy [ev] view of the SNR HESS J- e XMM-Newton the Norm. surface brightness. surface brightness E 2 dn/de [erg s cm 2 ] and interact with each other. In this radio case the fact that part of the 0. X-ray shell appears in the foreground could be explained by irregularitev the absorbing cloud. ties in the distribution of material within.0 ThisWest conclusion North is supported East by the fact that no significant South West X-ray emission is detected from the western part of the remnant. Indeed, apparent difference in the X-ray June morphology - - there is anx-ray Universe, Rome, 6-
Asymmetry: HESS J- vs. RX J.-6 HESS J- (rotated) RX J.-6 Images by F. Acero RX J.-6: High (non-thermal) X-ray emissivity explained with high gas density HESS J-: similar X-ray geometry as RX J.-6, still possibly a different explanation: TeV emissivity pattern is different! X-ray - dim part in region of high gas density (if co-location interpretation is correct) XMM-Newton view of the SNR HESS J- - 6 - X-ray Universe, Rome, June 6-
A blend of leptonic and hadronic TeV emission? Not a complete model, just for illustration Full SNR North-West (region ): TeV excess modeled by additional hadronic component XMM-Newton view of the SNR HESS J- - - X-ray Universe, Rome, June 6-
Conclusion SNR age: Age of 2 kyrs (Tian et al. 0) was most likely overestimated (simple Sedov SNR solution) Cui, GP et al. 6: 2. 6. kyrs Doroshenko, GP et al. 6: ~. kyrs Distance: most likely.2 kpc (this work); see also Maxted et al., submitted distance to companion star (Doroshenko, GP et al. 6):.±0. kpc (Vickers et al. ) SNR likely in a wind bubble (Cui, GP et al. 6) SNR likely co-located with dense gas material at.2 kpc (this work) SNR possibly interacting with dense cloud in the West; dimming of non-thermal X-rays due to slowing shocks? No thermal X-rays detected yet... TeV emissivity and X-ray (intrinsic) non-thermal emissivity different (on large scale across the SNR): TeV emission possibly a blend of leptonic and hadronic emission? XMM-Newton view of the SNR HESS J- - - X-ray Universe, Rome, June 6-