Title Imaging the molecular gas in high redshift FIR-luminous Pi C. Carilli Time 60 hrs 1.6.3: Name -- Imaging the molecular gas in high redshift FIR-luminous QSOs Authors: C. Carilli 2. Science goal: We propose high resolution (0.2") imaging of the CO emission from high redshift (z=4 to 6.4) QSOs. Studies of high redshift QSOs have shown that about 30% of the sources are luminous FIR sources, corresponding to thermal emission from warm dust, with dust masses >= 1e8 M_sun (eg. Omont et al. 2003, A&A 398, 857; Carilli et al. 2002 ApJ 555, 625). In all cases studied with adequate sensitivity (and redshift accuracy), CO emission has also been detected, with typical line peak flux densities for the 5-4 transition (redshifted to band 3 of ALMA) >= 2 mJy. Various lines of argument suggest that the dominant dust heating mechanism is star formation, implying star formation rates of order 1e3 M_sun/year, although the AGN could also contribute to the dust heating. The coexistence of massive starbursts and major accretion events onto supermassive black holes, is consistent with the idea of coeval SMBH-galaxy formation at high redshift, as suggested by the close correlation between black hole mass and bulge mass seen in nearby spheroidal galaxies. Imaging the CO emission provides the only means of determining the dynamical mass of the host galaxy, and also provides information on the nature and physical conditions of the earliest galaxies. In particular, determining the distribution of the molecular gas and dust relative to the AGN could help to constrain the dust heating mechanism, as well as reveal complex/multiple sources, as might be expected in for hierarchical structure formation. We will observe a representative sample of 5 sources using band 3 in A configuration (0.17" resolution). The typical sizes inferred for the CO emitting regions are between 0.2 and 2". Assuming a characteristic size of order 1" implies a typical expected surface brightness of about 0.1 mJy/beam for a 50 km/s channel. 3. Number of sources: 5 4. Coordinates: 4.1. Choose equatorial sources from SDSS/DPSS, selected as FIR-luminous QSOs from single-dish bolometer surveys (eg. next generation MAMBO/SCUBA), and detected in CO emission using LMT or GBT (or small configuration ALMA survey). 4.2. Moving target: no 4.3. Time critical: no 5. Spatial scales: 5.1. Angular resolution: 0.17" 5.2. Range of spatial scales/FOV: 0.17" to 4" 5.3. Single dish: no 5.4. ACA: no 5.5. Subarrays: no 6. Frequencies: 6.1. Receiver band: Band 3 -- 100 GHz in Configuration A 6.2. Lines and Frequencies 6.3. Spectral Resolution (km/s) 50 km/s 6.4. Bandwidth or spectral coverage: 8 GHz (for continuum sensitivity) with 512 spectral channels/polarization 7. Continuum flux density: 7.1. Typical value: 1 mJy 7.2. Continuum peak value: 7.3. Required continuum rms: 0.002 mJy/beam 7.4. Dynamic range in image: 8. Line intensity: 8.1. Typical value: 0.1 mJy/beam/channel 8.2. Required rms per channel: 0.035 mJy/beam/channel 8.3. Spectral dynamic range: 9. Polarization: no 10. Integration time per setting: 5 sources at 2x6 hrs per source 11. Total integration time for program: 60 hr Notes: could be included in 1.1 or 1.5. A parallel program could be to search for CO emission from high z QSOs, but this could also be done with LMT/GBT. The unique aspect of ALMA is the high resolution imaging. For some sources it might be possible to do multiple transitions (eg. 5-4 and 6-5) within band 3 simultaneously, thereby allowing for study of excitation gradients. ************************************************************************ Review Jean Turner: An area which is very popular right now, and in which not very much is known. 60 hours is not much time, given how much there is to be learned here; even a detection gives a lot of information about the early universe. The total time for this project could easily be increased given the present interest in these galaxies. ALMA is better suited to this study than the LMT because of the high resolution. Technical: angular resolution is appropriate. 12 hours per source is actually not much time for these sources. They're weak. However at the moment this is somewhat arbitrary. (It's actually difficult to judge this proposal for that reason, not much is known now and it's all pretty arbitrary) Integrations: checked and numbers about right. See 1) about total increase in time. I'm guessing ALMA will spend a LOT more time on this area, given recent experience at OVRO. Comment Ewine: some of these sources will likely also be covered in section 1.1. Since there will be many of these types of programs, it is good to have some duplicates with slightly different strategies. Increase sample here to 10 sources => 120 hr assuming 12 hr/source -------------------------------------------------- Review v2.0: 1.6.5 Imaging the molecular gas in high redshift FOR-luminous QSOs (Carilli) Not revised since DRSP 1.1. Nothing needs to be added to the review back then, no severe impact through reduction to 50 antennas, no need for ACA. I agree that this is a quite hot topic right now, and even though a lot of progress has been made, particularly with PdB, since the last review, the topic will most likely not be exhausted when ALMA comes on line, we'll see a lot more proposals like that, for a larger sample, and possibly also for higher resolution.