Exploring structure around submillimetre-bright QSOs

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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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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

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Introduction our hard QSO sample(Page01,04,10
Stevens04,05)

• 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 zgt1.5
• 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

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Environment in submm SCUBA 850?m
(Stevens05,10)
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 _at_z)
• Some disturbed morphol.
• Major galaxy merger

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Confirmation for RXJ0941 radio imaging

• 4 450?m sources, 3 850 ?m sources (2 in common)
  5 total
• All in radio (plus blob?) (Carrera10)

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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 _at_3646Å
• _at_z1.82 between Z and J
• MK bulge (stellar) mass M from Borys05
• Also used MRR08 (diff M/L) a factor 2-3 larger

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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-Sansigre09)
  ? dust mass

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RXJ0941 the QSO850_1/450_1
i K 4.5?m 8?m 24?m 450?m
850?m 6cm 20cm

• z1.82
• Several components
• AGN direct accretion (MRR08)
• AGN re-processing torus (MRR08)
• Star formation LIR2x1013L?
• Dominates in MIR/submm
• SFR4000M?/y

F?(cgs/Å)
?obs(Å)
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850_2/450_2
i K 4.5?m 8?m 24?m 450?m
850?m 6cm 20cm
Phot. z1.85LIR2x1013L?SFR4000M?/ylog(M/M?)
11.6
F?(cgs/Å)
Photo-z fit CE01 450µm CE01 850µm
?obs(Å)
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i K 4.5?m 8?m 24?m 450?m
850?m 6cm 20cm
850_3
Phot. z1.85LIR0.5x1013L?SFR900M?/ylog(M/M?)
11.5
F?(cgs/Å)
Photo-z fit CE01 4.5µm CE01 850µm
?obs(Å)
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i K 4.5?m 8?m 24?m 450?m
850?m 6cm 20cm
450_4
F?(cgs/Å)
Phot. z1.85LIR1013L?SFR2400M?/y
log(M/M?)11.5
Photo-z fit CE01 450µm
?obs(Å)
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i K 4.5?m 8?m 24?m 450?m
850?m 6cm 20cm
450_3
F?(cgs/Å)
Phot. z2.8LIR2x1013L?SFR4000M?/y
log(M/M?)11.5
Photo-z fit CE01 4.5m CE01 450µm
?obs(Å)
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Table summary
Source z LIR (1013L?) SFR (M?/y) Mdust (108M?) logM (logM?) Flux (µJy) 450(850)µm
850_1/450_1 1.82 2.4 4100 5-22 - 40?10
850_2/450_2 1.85 2.2 3800 4-23 11.6 40?10
850_3 1.85 0.5 900 2-6 11.5 (3?2)
450_3 2.8 2.1 3600 4-25 11.3 34?9
450_4 1.85 1.4 2400 3-16 11.5 29?8

• One spurious expected from logN-logS (Coppin06)
• log(M/M?)11.5?0.2 (inc. ?z and ?K)
• SFR2000 M?/y
• Mdust109M? (interval from ?z, ?T/?, ??)
• Mgas51010M? (Kovács06 SMG, Seaquist04 SCUBA)

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Presence of AGN

• X-ray upper limits on soft (610-16cgs) and hard
  (410-15cgs) bands
• Using Gilli07 models
• 2-10keV luminosity upper limits
• All 24µm from AGN very conservative (Elvis94)
• log(LX/cgs)lt44
• BC35 (Marconi04,Elvis94)
• ?0.2 (SMGs z2 low LX Alexander08)

hard
soft

• log(MBH/M?)lt8.1 ( log(BC/35)-log(?/0.2) )

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Evolutionary state(Borys05, Alexander08,
Michalowski10)

• log(M/M?)11.5?0.2 (other SMG samples)
• Schechter mass of MIR-sel gals.
  (Pérez-González08)
• Gas mass 10 galaxy mass
• Galaxy mature and not much further growth
• log(MBH/M?)lt8.1 (7.4-8.4 with ?BC, ??)
• (MBH/M)/(MBH/M)locallt 6 (1-100 with ?)
  (MarconiHunt 04)
• 1 only if flux at X-ray upper limit and NHgtgt
• LX51043 erg/s (SMG Alexander08), M2 if
  MRR08
• Growth of BH lags the growth of the galaxy

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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 t4.4108y ?/?(1-?)
  (Martínez-Sansigre Taylor 09, Rees 84)
• ?0.2 (low LX SMG Alexander08)
• ?0.08 (Marconi04, M-ST 09)
• MBH6 (local) t340My (over by z1.65)

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Summary

• We confirmed overdensity around RXJ0941
• Counterparts to 4/5 sources at same z
• Expected 1 spurious from submm source counts
• HLIRGs, SFR2000 M?/y
• Counterparts are massive submm galaxies
• Limited additional growth
• Already mature
• Any AGN must have log(MBH/M?)lt8.1
• 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

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And there are more...

• Photo-z successful for 225
• Peak 1.5-2
• Similar for BC03
• 89 sources close to z1.82 within 99 with ?3
  points
• M histogram for those 89
• Broad
• Narrower if only ?Mlt1 8-11
• All three counterparts in highest bins

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Interpretation an evolutionary sequence?
Joint spheroid/QSO evolution within a
hierarchical clustering scenario (Granato04,
Silk Rees 1998, Fabian99, Di Matteo05)

• 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

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Interpretation an evolutionary sequence?
Joint spheroid/QSO evolution within a
hierarchical clustering scenario (Granato04,
Silk Rees 1998, Fabian99, Di Matteo05)

• FIR emission increases ? ULIRGs
• Bulk of submm gal. population discovered by SCUBA
  (Smail97) ?
• As BH grows it reaches Sy-like X-ray luminosities
• Absorbed X-ray sources (Alexander05)
• Signatures of buried AGN in opt spec. (Chapman04)

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Interpretation an evolutionary sequence?
Joint spheroid/QSO evolution within a
hierarchical clustering scenario (Granato04,
Silk Rees 1998, Fabian99, Di Matteo05)

• Still forming stars (FIRgtgt)
• 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?
  (Fabian99)

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Interpretation an evolutionary sequence?
Joint spheroid/QSO evolution within a
hierarchical clustering scenario (Granato04,
Silk Rees 1998, Fabian99, Di Matteo05)