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Ringberg Meeting, Apr 05

Ringberg Meeting, Apr 05. 2dF Spectroscopic Identification of a Southern XMM-Newton Serendipitous Sample Jonathan Tedds (Leicester), Mat Page (MSSL) & XMM-Newton Survey Science Centre. Introduction. XMM-Newton X-ray serendipitous surveys

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Ringberg Meeting, Apr 05

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  1. Ringberg Meeting, Apr 05 2dF Spectroscopic Identification of a Southern XMM-Newton Serendipitous Sample Jonathan Tedds (Leicester), Mat Page (MSSL) & XMM-Newton Survey Science Centre

  2. Introduction • XMM-Newton X-ray serendipitous surveys • 2dF optical spectroscopic characterisation of X-ray sample • Unique science example: any BAL QSOs? • Summary Jonathan Tedds Leicester University

  3. The XMM-Newton serendipitous sky survey PI M.Watson (Leicester) • XMM-Newton with EPIC cameras • large FOV • large throughput • excellent high energy response • Every new XMM-Newton pointing discovers ~30-150 serendipitous X-ray sources. • 700 pointings/year  about 50,000 new X-ray sources/year • Angular resolution worse than Chandra • depth limited by confusion • (fx ~ 4 x 10-16, T~100 ksec) • But higher s/n X-ray spectra at medium/faint fluxes Jonathan Tedds Leicester University

  4. Core Programme ‘calibration’  Probable identification Imaging Programme SSC XID programme • statistical identifications for the whole XMM-Newton serendipitous catalogue • Core programme: spectroscopic IDs (1000 sources/sample): • High b faint sample (~10-15 erg cm-2 s-1) • High b medium sample (~10-14 erg cm-2 s-1) => AXIS (PI Barcons) + 2dF -> bulk of objects contributing to X-ray background are at fluxes ~ 10-14 : depth of XMM serendipitous survey • High b bright sample (~10-13 erg cm-2 s-1) => Della Ceca et al 04 • Galactic Plane Sample (~7 10-15 erg cm-2 s-1) => PI Motch • Imaging programme (u,g’,r’,i’,Z,H): a large number of XMM-Newton fields X-ray properties + Optical/IR photometric imaging Jonathan Tedds Leicester University

  5. XMM-Newton 1 y Chandra 1 y pencil beam surveys XMM LH/HDFN Chandra HDFN/CDF ... X-ray surveys ROSAT soft band 10 y SAX/ASCA Jonathan Tedds Leicester University

  6. 2df ID Motivation – Characterise X-ray Sky • AXIS (PI Barcons, IFCA) making a major contribution towards characterising the XMM medium sample in North • Striving for an unbiased survey with statistical completeness • But 1000 sources target very ambitious! • Solution: 2dF at the AAT in South • Complement AXIS • Very high observing efficiency • simply aim for the maximum identification rate

  7. What do we get?

  8. How much have we observed? • 5 pointings with 2dF in 02/03 • 22 pointings with 2dF in 03/04 • 68 XMM fields including LSS fields – some multiple exposures • Typically 1hr exposures • any X-ray source with an optical counterpart that could be allocated a fibre • 1/3 of fields have WFC/WFI multiband opt imaging • In total > 3000 X-ray sources observed and reduced • Identification stage almost complete and we have certainly beaten the barrier of 1000 sources brighter than F0.5-4.5 > 10-14 ergcm-2 s-1 • Opens up unique areas of parameter space

  9. Distribution of 2dF fields on sky Jonathan Tedds Leicester University

  10. Provisional 2dF ID statistics area~8 deg2 , >50% ID rate, ~50% final sample Jonathan Tedds Leicester University

  11. XID: high-b identifications Jonathan Tedds Leicester University

  12. Provisional 2dF ID statistics Jonathan Tedds Leicester University

  13. Unique science example:Broad Absorption Line QSOs • 3-5% of optically selected QSOs (SDSS ~10-20%?) • Virtually absent in previous X-ray surveys because of absorption • None in ROSAT surveys! • But are there any which are transmissive enough to be picked up in current X-ray surveys? • Certainly will require a large survey to have a hope of detecting more than one or two • Not heavily obscured in the optical - perfect area to be addressed by 2dF medium survey

  14. Example BALQSOs found with 2dF XMM: F0.5-4.5=1.2x10-14ergs-1cm-2 XMM: F0.5-4.5=8.6x10-15ergs-1cm-2

  15. Example BALQSOs found with 2dF XMM: F0.5-4.5=9.4x10-15ergs-1cm-2 Jonathan Tedds Leicester University

  16. Broad absorption line QSOs • >10 BALQSOs found cf ~1000 QSOs • 1-2% of the X-ray QSO population • 1/3 the fraction found in past optical surveys • (this is suprisingly large… but new SDSS result?) • The X-ray selected ones will have the lowest X-ray absorption of the BALQSO population • Are their optical absorption lines typical of the optically selected population? • What are their X-ray column densities? • Reprocessing of all 2dF XMM data just completed • Watch this space!

  17. Z=3.052 BAL QSOFX=5x10-15 cgs, power law = 1.66, NH=1020 Bj=22.46 broad Lyb, Lya/NV/SiII + weak abs, broad CII SiIV/OIV NIV] CIV [NIII] CIII] Jonathan Tedds Leicester University

  18. High z quasars • What is the space density of z~4 QSOs in X-ray surveys - do they decline at z > 2 in the same way that optical QSOs do? • What are their X-ray spectra? • How common is X-ray absorption? • Ly-alpha in optical red, relatively easy objects to identify spectroscopically, but fairly rare on the sky - 2dF survey ideal • WFC,ESO mags for some fields - dropouts Jonathan Tedds Leicester University

  19. High z quasars XMM: F0.5-4.5=2.0x10-14ergs-1cm-2 XMM: F0.5-4.5=7.6x10-15ergs-1cm-2 Jonathan Tedds Leicester University

  20. Multi epoch data e.g. Clusters in ~70% of fields • combine spectra • variability GTI=78ks, extent=43” GTI=80ks, extent=49” GTI=23ks, extent=43” Jonathan Tedds Leicester University

  21. Summary • 2dF ID >1000 sources brighter than F0.5-4.5 > 10-14 ergcm-2 s-1 • Homogeneous X-ray data reprocessing just completed • Characterise XRB source population • Optical multiband imaging complete for ½ fields (WFC,ESO…) • Opt mag dropouts? • Excellent statistical ID training sample • XMM serendipitous survey = WIDE coverage! • Larger no of rare objects than deep, narrow surveys to date, e.g. • X-ray selected BAL QSOs => SDSS agreement? • High-z AGN Jonathan Tedds Leicester University

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