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Exploring structure around submillimetre-bright QSOs

Exploring structure around submillimetre-bright QSOs. Francisco J. Carrera (IFCA, CSIC-UC, Spain/Imperial, UK) Mathew J. Page (MSSL-UCL, UK) Jason Stevens (CAR, U. Hertfordshire, UK) Rob Ivison (ROE, UK) Serena Falocco (IFCA, CSIC-UC, Spain), Jacobo Ebrero (SRON, NL). MSSL, 14-July- 2010.

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Exploring structure around submillimetre-bright QSOs

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  1. Exploring structure around submillimetre-bright QSOs Francisco J. Carrera (IFCA, CSIC-UC, Spain/Imperial, UK) Mathew J. Page (MSSL-UCL, UK) Jason Stevens (CAR, U. Hertfordshire, UK) Rob Ivison (ROE, UK) Serena Falocco (IFCA, CSIC-UC, Spain), Jacobo Ebrero (SRON, NL) MSSL, 14-July- 2010

  2. Outline • Introduction: our hard QSO sample • What we now so far about them • Environment in submm: strong overdensities • Confirmation for RXJ0941 • Radio imaging • SEDs • Presence of AGN • Evolutionary status • Summary

  3. Simultaneous strong growth of BH and star formation Stronger SF in the past Transitory phase ~10-15% QSO life Just starting to blow away circumnuclear material? Introduction: our hard QSO sample(Page+01,04,10 Stevens+04,05) • Sample of Broad Line QSO with X-ray absorbed spectra • At z and LX where most contribution to X-ray background • Matched sample of similar (LX,z) unabsorbed QSO • Strong difference in submm fluxes: • Absorbed mostly bright, unabsorbed mostly faint • All submm detected are at z>1.5 • Submm much too bright to come from AGN: strong star formation • Absorbed BLQSO are ~10-15% of BLQSO population • X-ray-UV spectra: strong ionized winds, enough to terminate SF

  4. ~400kpc ~2´ Environment in submm: SCUBA 850m (Stevens+05,+10) These QSOs are sitting in overdensities in the Universe Submm luminosity from starburst (triggered by fusion/interaction?) • 2-4x overdensities • Structure in 100skpc • Each an ULIRG (if @z) • Some: disturbed morphol. • Major galaxy merger

  5. iK4.5m 8m 24m 450m 850m 6cm 20cm Confirmation for RXJ0941: radio imaging • 4 450m sources, 3 850 m sources (2 in common): 5 total • All in radio (plus blob?) (Carrera+10)

  6. Confirmation for RXJ0941: photo-z • Radio imaging: submm sources real • pinpoint some counterparts • Counterparts very faint for spectroscopy • Photometric redshifts (hyperz): • Fitting spectral templates (MRR08) to RiZJK-4.5,8μm • Also tried Bruzual & Charlot 2003: similar z • Only fit to rest-frame optical-NIR: no dust • Best if conspicuous feature: Balmer break @3646Å • @z=1.82: between Z and J • MK: bulge (stellar) mass M* from Borys+05 • Also used MRR08 (diff M/L): a factor 2-3 larger

  7. Confirmation for RXJ0941: z and SEDs • Once z: Spectral Energy Distribution (SED) • Using Chary & Elbaz 2001 templates for ≥MIR • Dust emission • Not expected good match to rest-frame Opt.-NIR • But surprisingly good… • Not fit: renormalizing to 450μm, 850μm, 4.5μm,… • From CE01 templates: • LIRStar Formation Rate (SFR) (Kennicutt 1998) • From 450μm/850μm fluxes: • Assuming (T/,) (QSO/SMGs Martínez-Sansigre+09)  dust mass

  8. iK4.5m 8m 24m 450m 850m 6cm 20cm RXJ0941: the QSO850_1/450_1 • z=1.82 • Several components: • AGN direct accretion (MRR+08) • AGN re-processing: torus (MRR+08) • Star formation: LIR~2x1013L • Dominates in MIR/submm • SFR~4000M/y F(cgs/Å) obs(Å)

  9. 850_2/450_2 iK4.5m 8m 24m 450m 850m 6cm 20cm Phot. z=1.85LIR~2x1013LSFR~4000M/ylog(M*/M)~11.6 F(cgs/Å) Photo-z fit CE01 450μm CE01 850μm obs(Å)

  10. iK4.5m 8m 24m 450m 850m 6cm 20cm 850_3 Phot. z=1.85LIR~0.5x1013LSFR~900M/ylog(M*/M)~11.5 F(cgs/Å) Photo-z fit CE01 4.5μm CE01 850μm obs(Å)

  11. iK4.5m 8m 24m 450m 850m 6cm 20cm 450_4 F(cgs/Å) Phot. z=1.85LIR~1013LSFR~2400M/y log(M*/M)~11.5 Photo-z fit CE01 450μm obs(Å)

  12. iK4.5m 8m 24m 450m 850m 6cm 20cm 450_3 F(cgs/Å) Phot. z=2.8LIR~2x1013LSFR~4000M/y log(M*/M)~11.5 Photo-z fit CE01 4.5m CE01 450μm obs(Å)

  13. Table summary • One spurious expected from logN-logS (Coppin+06) • log(M*/M)~11.50.2 (inc. z and K) • SFR~2000 M/y • Mdust~109M (interval from z, T/, ) • Mgas~5×1010M (Kovács+06 SMG, Seaquist+04 SCUBA)

  14. Presence of AGN • X-ray upper limits on soft (6×10-16cgs) and hard (4×10-15cgs) bands: • Using Gilli+07 models • 2-10keV luminosity upper limits • All 24μm from AGN: very conservative (Elvis+94) • log(LX/cgs)<44 • BC~35 (Marconi+04,Elvis+94) • ~0.2 (SMGs z~2 low LX Alexander+08) hard soft • log(MBH/M)<8.1 ( +log(BC/35)-log(/0.2) )

  15. Evolutionary state(Borys+05, Alexander+08, Michalowski+10…) • log(M*/M)~11.50.2 (~other SMG samples): • ~Schechter mass of MIR-sel gals. (Pérez-González+08) • Gas mass ~10% galaxy mass • Galaxy mature and not much further growth • log(MBH/M)<8.1 (7.4-8.4 with BC, ) • (MBH/M*)/(MBH/M*)local< 6 (1-100 with ) (Marconi&Hunt 04) • ~1 only if flux at X-ray upper limit and NH>> • LX~5×1043 erg/s (SMG Alexander+08), M*×2 if MRR08… • Growth of BH lags the growth of the galaxy

  16. Evolutionary state • Plenty of fuel for AGN growth: • Only ~1.5% of Mgas into BH to reach local MBH-M* • If BH in exponential growth phase: • Mass e-folding time: t=4.4×108y × /(1-) (Martínez-Sansigre & Taylor 09, Rees 84) • =0.2 (low LX SMG Alexander+08) • =0.08 (Marconi+04, M-S&T 09) • MBH×6 (local): t~340My (over by z~1.65)

  17. Summary • We confirmed overdensity around RXJ0941 • Counterparts to 4/5 sources at same z • Expected ~1 spurious from submm source counts • HLIRGs, SFR~2000 M/y • Counterparts are massive submm galaxies: • Limited additional growth • Already mature • Any AGN must have log(MBH/M)<8.1 • Below local MBH/M* relationship • Growth of BH lags growth of galaxy • Growth of AGN feasible: • Enough fuel • Relatively quickly • Need: Herschel to measure submm SED shape (good T/, Mdust…), deeper X-ray to measure MBH, photo-z for the rest…

  18. And there are more... • Photo-z successful for 225 • Peak ~1.5-2 • Similar for BC03 • 89 sources “close” to z=1.82 within 99% with 3 points • M* histogram for those 89: • Broad • Narrower if only M*<1: 8-11 • All three counterparts in highest bins

  19. X-ray FIR Interpretation: an evolutionary sequence? Joint spheroid/QSO evolution within a hierarchical clustering scenario(Granato+04, Silk & Rees 1998, Fabian’99,Di Matteo+05) • More massive DM halos collapse earlier • Collisions and mergers occur • These processes channel material to the center which • Makes stars • Feeds the BH • Material obscures opt/UV (dust) and X-ray (gas) • Heated dust emits FIR which escape unimpeded

  20. X-ray X-ray FIR FIR Interpretation: an evolutionary sequence? Joint spheroid/QSO evolution within a hierarchical clustering scenario(Granato+04, Silk & Rees 1998, Fabian’99,Di Matteo+05) • FIR emission increases  ULIRGs • Bulk of submm gal. population discovered by SCUBA (Smail+97) ? • As BH grows it reaches Sy-like X-ray luminosities • Absorbed X-ray sources (Alexander+05) • Signatures of buried AGN in opt spec. (Chapman+04)

  21. X-ray X-ray FIR FIR X-ray  our X-ray absorbed QSOs FIR Interpretation: an evolutionary sequence? Joint spheroid/QSO evolution within a hierarchical clustering scenario(Granato+04, Silk & Rees 1998, Fabian’99,Di Matteo+05) • Still forming stars (FIR>>) • BH allmost fully grown: QSO luminosities • QSO radiation and starbursts are starting to sweep out circumnuclear material: • Less absorbed X-ray sources  our X-ray absorbed QSOs • BALQSOs in slightly later stage? (Fabian’99)

  22. X-ray X-ray FIR FIR • Fully grown QSO “living off the rents”  our X-ray unabsorbed QSOs • Passively evolving stellar population X-ray X-ray  our X-ray unabsorbed QSOs FIR Interpretation: an evolutionary sequence? Joint spheroid/QSO evolution within a hierarchical clustering scenario(Granato+04, Silk & Rees 1998, Fabian’99,Di Matteo+05)

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