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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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
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
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 SFSimultaneous strong growth of BH and star formationStronger SF in the pastTransitory phase ~10-15% QSO lifeJust starting to blow away circumnuclear material?
Environment in submm: SCUBA 850m
(Stevens+05,+10)
~40
0kp
c ~2´
• 2-4x overdensities• Structure in 100skpc• Each an ULIRG (if @z)• Some: disturbed
morphol.– Major galaxy merger
These QSOs are sitting in overdensities in the UniverseSubmm luminosity from starburst (triggered by fusion/interaction?)
Confirmation for RXJ0941: radio imaging
• 4 450m sources, 3 850 m sources (2 in common): 5 total• All in radio (plus blob?) (Carrera+10)
i K 4.5m
8m 24m 450m
850m 6cm 20cm
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
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
F(
cgs/
Å)
RXJ0941: the QSO
850_1/450_1
i K 4.5m
8m 24m 450m
850m 6cm 20cm
obs(Å)
• 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
850_2/450_2
Phot. z=1.85LIR~2x1013L
SFR~4000M/ylog(M*/M)~11.6
obs(Å)
F(
cgs/
Å)
i K 4.5m
8m 24m 450m
850m 6cm 20cm
Photo-z fitCE01 450μmCE01 850μm
obs(Å)
F(
cgs/
Å)
850_3
Phot. z=1.85LIR~0.5x1013L
SFR~900M/ylog(M*/M)~11.5
i K 4.5m
8m 24m 450m
850m 6cm 20cm
Photo-z fitCE01 4.5μmCE01 850μm
Phot. z=1.85LIR~1013L
SFR~2400M/y log(M*/M)~11.5
obs(Å)
F(
cgs/
Å)
450_4
i K 4.5m
8m 24m 450m
850m 6cm 20cm
Photo-z fitCE01 450μm
Phot. z=2.8LIR~2x1013L
SFR~4000M/y log(M*/M)~11.5
i K 4.5m
8m 24m 450m
850m 6cm 20cm
450_3
obs(Å)
F(
cgs/
Å)
Photo-z fitCE01 4.5m
CE01 450μm
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 - 4010
850_2/450_2 1.85
2.2 3800 4-23 11.6 4010
850_3 1.85
0.5 900 2-6 11.5 (32)
450_3 2.8 2.1 3600 4-25 11.3 349
450_4 1.85
1.4 2400 3-16 11.5 298• One spurious expected from logN-logS (Coppin+06)
• log(M*/M)~11.50.2 (inc. z and K)• SFR~2000 M/y• Mdust~109M (interval from z, T/, )
– Mgas~5×1010M (Kovács+06 SMG, Seaquist+04 SCUBA)
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