Millimeter and Radio studies of Millimeter and Radio studies of z~6 Quasarsz~6 Quasars

Millimeter and Radio studies of Millimeter and Radio studies of z~6 Quasarsz~6 Quasars

Ran WangDepartment of Astronomy, Peking University,

China

Supervisor: Chris Carilli ( NRAO), Xue-Bing Wu (PKU)Collaborators: Bertoldi, F. (University of Bonn); Cox, P. (IRAM); Fan, X. (University of Arizona); Jiang, L. (University of Arizona); Menten, K. (MPIfR); Omont, A. (IAP); Strauss, M. (Princeton); Wagg, J. (NRAO); Walter, F. (MPIfA)

Introduction – The discovery of Introduction – The discovery of z~6 quasarsz~6 quasars

1148+5251 z=6.42

Beelen et al. 2006

Walter et al. 2004; Carilli et al. 2008

IntroductionIntroductionIntroductionIntroduction

• We are pursuing cm and mm studies of all the quasars discovered at z~6

SampleSampleSampleSample

• There are totally Thirty-three quasars discovered at z~6.– z=5.71 to 6.43– M_1450A < -25.0

• Twenty-two from the SDSS survey of ~8000 deg^2 area, with m1450A < 20.

• Nine from deeper optical imaging with m1450A>20, Jiang et al. 2007; Wollitt et al. 2007

• IR (Spitzer) + optical: one; Cool et al. (2006)• Radio (FIRST) + optical: one; McGreer et al. (2006)

Most of these objects were optically selected from the SDSS survey

Represent the most luminous quasar population at z~6.

SHARC-II CSO

PdBI IRAM

ObservationsObservationsObservationsObservations

MAMBO IRAM-30mVLA

A summary of the (sub)mm and A summary of the (sub)mm and radio Resultsradio Results

A summary of the (sub)mm and A summary of the (sub)mm and radio Resultsradio Results

• MAMBO observations of 33 sources– rms in the range of 0.4 to 1.1 mJy with a

median value of 0.6 mJy– Ten are detected at ≥ 3 σ level

• VLA observation of 32 sources– rms ≤ 20 uJy for most of the sources – Ten were detected, with two of them having

flux densities > 1mJy– Three of them have radio loudness R ≥10

• CO observations of the bright mm detections.

Av

GHzv

f

fR

4400,

5,

The average FIR and radio The average FIR and radio emissionemission

The average FIR and radio The average FIR and radio emissionemission

FIR-millimeter spectral index ~2

Wang et al. (2008 submitted)

The bright millimeter detectionsThe bright millimeter detectionsThe bright millimeter detectionsThe bright millimeter detections

•The FIR emission exceeds that of the local quasar template.

•The FIR SED is consistent with optically thin gray-body emission from 40 ~ 50 K dust.

•The FIR-to-radio SED is consistent with that of typical star forming galaxies.

•Dust mass: ≥108 Msun

•FIR luminosity ~ 1013 Lsun

•Observations at 2mm and 3mm will determine the emissivity index.

CO detectionsCO detectionsCO detectionsCO detections

•Molecular CO emission has been detected in the mm bright quasars.

•Gas mass : M(H2) ≥ 1010 Msun .

•CO line width of the new detections: FWHM ≥ 500 km/s

•The median value is 300 km/s for previous CO detected quasars at high-z.

Carilli et al. 2007

Luminosity correlation LLuminosity correlation LFIRFIR – L – L’’COCOLuminosity correlation LLuminosity correlation LFIRFIR – L – L’’COCO

Luminosity correlation LLuminosity correlation LFIRFIR - L - LBolBolLuminosity correlation LLuminosity correlation LFIRFIR - L - LBolBol

Wang et al. (2008 in press)

Discussion – star formation in the z~6 Discussion – star formation in the z~6 quasarsquasars

Discussion – star formation in the z~6 Discussion – star formation in the z~6 quasarsquasars

• The MAMBO undetected quasars at z~6:– The average FIR-to-radio SED is consistent with the

templates of local optical quasars.– The average FIR to AGN-bolometric luminosity ratio follows

the trend defined by local PG quasars.

• The average FIR luminosity: 1.2x1012 Lsun

– Even 50% of the FIR emission from star formation, the star formation rate => 200 Msun yr-

1

– The major bulge building stage via starburst has been finished ?

Discussion – star formation in the z~6 Discussion – star formation in the z~6 quasarsquasars

Discussion – star formation in the z~6 Discussion – star formation in the z~6 quasarsquasars

• The mm and CO detected quasars at z~6:– FIR emission from 40 ~ 50 K warm dust.– Properties similar to that of star forming

galaxies.

– Derived star formation rate: ≥ 103 Msun yr-1

– Gas depletion time: Mgas/SFR ~ 107 yr .

– Active bulge building via massive star formation co-eval with SMBH accretion.

– Black hole-bulge mass ratio : high-resolution CO mapping.