Presentation is loading. Please wait.

Presentation is loading. Please wait.

Molecular gas in the z~6 quasar host galaxies Ran Wang National Radio Astronomy Observatory Steward Observatory, University of Atrizona Collaborators:

Similar presentations


Presentation on theme: "Molecular gas in the z~6 quasar host galaxies Ran Wang National Radio Astronomy Observatory Steward Observatory, University of Atrizona Collaborators:"— Presentation transcript:

1 Molecular gas in the z~6 quasar host galaxies Ran Wang National Radio Astronomy Observatory Steward Observatory, University of Atrizona Collaborators: Bertoldi, F. (University of Bonn); Chris Carilli (NRAO); Cox, P. (IRAM); Fan, X. (University of Arizona); Menten, K. (MPIfR); Neri, R. (IRAM); Omont, A. (IAP); Riechers, D. (Caltech); Strauss, M. (Princeton); Wagg, J. (NRAO); Walter, F. (MPIfA)

2 Study the formation and early evolution of the quasar-host systems in the most distant universe via mm and cm observations. –Mm dust/cm radio continuum/fine structure interstellar cooling lines: star forming activities in the quasar host galaxies  growth of the stellar bulge. –Molecular CO emission: fuel of the star formation, dynamical mass of the spheroidal bulge. SMBH-host evolution in the most distant universe The formation of the SMBHs and their spheroidal bulges are suggested to be tightly coupled. Fan et al. 2006

3 A sample of 33 z~6 quasars has been observed with MAMBO at 250 GHz, with a median rms of ~0.6 mJy. Ten of them have been detected: ~30%. The mm bright quasars at z~6 IRAM-30m

4 Luminosity correlations (eg. FIR vs. AGN, FIR vs. radio) consistent with the extreme star forming systems. The mm bright quasars at z~6 Strong FIR emission from ~40 to 60 K dust, exceeding that of the local optical quasar template. Wang et al Data: Fan et al. 2004; Jiang et al. 2006; Leipski et al. 2010; Beelen et al. 2006; Robson et al. 2004; Bertoldi et al. 2003; Carilli et al. 2004

5 The mm bright quasars at z~6 A sample of 8 z~6 quasars with 250 GHz flux densities >= 1.8 mJy, based on the MAMBO dust continuum observations. The brightest mm detections: J and J have been detected in strong molecular CO line emission (Walter et al. 2003; Bertoldi et al. 2003; Carilli et al. 2007; Riechers et al. 2009). We observe the other six objects with the PdBI to search for high order CO transitions (6-5 and/or 5- 4). Walter et al Riechers et al. 2009

6 D configuration: FWHM~5”, ~29 kpc at z~6; Two tracks on each of the targets, covering a band width of 1.8 GHz; FOV: FWHM~50”; Unresolved. IRAM-PdBI

7 All the six z~6 quasars has been detected in molecular CO emission. –A sample of eight mm continuum and CO detected quasars at z~6. Host galaxy redshift: accurate to ≤0.002; CO line width: 160 ~860 km/s. –Line width distribution : similar to that of the SMGs and CO detected quasars at lower redshifts. –The source with the largest line width show a possible double- peak line profile. Molecular CO from the z~6 quasar hosts Wang et al. 2010

8 Molecular gas mass distributions : –similar to that of the SMGs and 1.4≤z≤5.0 CO-detected quasars. –An order of magnitude smaller than that of the star forming galaxies found at z~1 to 2 (eg. Daddi et al. 2010; Tacconi et al. 2010). Molecular gas mass distribution

9 CO excitation in the z~6 quasar hosts Warm, highly excited molecular gas with T kin ~50 K and n(H 2 ) ~ cm -3 (Riechers et al. 2009). Similar to that in the FIR and CO detected quasars at lower redshifts (eg. BR at z=4.69, Riechers et al. 2006) and some nearby starburst galaxies (eg. M82, Weiss et al. 2005).

10 FIR-CO luminosity relationship. Star formation rate: 530 to 2380 M sun yr -1. Gas depletion time scale: 10 7 yr, similar to that of the extreme starburst systems, such as the SMGs, ULIRGs, and much smaller that of the star forming galaxies found at z~1 and 2 (Daddi et al. 2010; Tacconi et al. 2010). Wang et al. 2010

11 CO estimated stellar mass with assumption of disk radius, inclination angles. i.e. M dyn : ~f·R·V FWHMCO 2 /G/sin 2 i; M bulge ~M dyn (R, sini)-M gas. Wang et al. 2010

12 Small inclination angles of i <5 to 15 degree are required for most of the sources However, the obscured fraction is probably ≤50% for the very luminous quasars: large torus opening angle at high luminosity (Simpson 2005; Treister et al. 2008)  inclination angle range of about 0 to 60 degree. An average inclination angle of 40 degree: M BH /M bul ~0.022, fifteen times higher than the present-day value. Difficulties : How the observed CO line widths trace the bulge dynamical properties, unknown molecular disk size, inclination angle  high-resolution observations

13 Molecular CO has been detected in a sample of eight mm bright quasars at z~6. The CO detections suggest the presence of highly excited molecular gas in the quasar host galaxies, with molecular gas masses on order of M sun. The gas mass and line width distributions are similar to that of the CO detected SMGs and quasars at z from 1 to 5. FIR-CO luminosity relation: Active bulge building via massive star formation at a rate of a few 100 to 1000 M sun yr -1. Estimations of the dynamical mass of the quasar stellar bulge based on the CO observations suggest a black hole- bulge mass ratio about 15 times higher than that of the present-day value. However, high-resolution observations are still required to fully understand the molecular gas distribution and dynamical properties Summary

14 Companion source close to J1048 CO (6-5) line emission from a companion source northeast to the quasar: ~28”away, redshift z=6.2259, close to the quasar redshift of z= Wang et al. 2010


Download ppt "Molecular gas in the z~6 quasar host galaxies Ran Wang National Radio Astronomy Observatory Steward Observatory, University of Atrizona Collaborators:"

Similar presentations


Ads by Google