Paul A. Vanden Bout

Connecting dense gas tracers of star formation in our galaxy to high-z star formation

Observations have revealed prodigious amounts of star formation in starburst galaxies as traced by dust and molecular emission, even at large redshifts. Recent work shows that for both nearby spiral galaxies and distant starbursts, the global star formation rate, as indicated by the infrared luminosity, has a tight and almost linear correlation with the amount of dense gas as traced by the luminosity of HCN. Our surveys of Galactic dense cores in HCN 1-0 emission show that this correlation continues to a much smaller scale, with nearly the same ratio of infrared luminosity to HCN luminosity found over 7-8 orders of magnitude in, with a lower cutoff L(IR) around 10(4.5) L(circle dot) of infrared luminosity. The linear correlation suggests that we may understand distant star, formation in terms of the known properties of local star-forming regions. Both the correlation and the luminosity cutoff can be explained if the basic unit of star formation in galaxies is a dense core, similar to those studied in our Galaxy.

IRAS F15307+3252: A hyperluminous infrared galaxy at z = 0.93

A new hyperluminous infrared galaxy in the Infrared Astronomy Satellite (IRAS) Faint Source Catalog is identified at a redshift of 0.93. This object has a bolometric luminosity of approximately 10(exp 13) solar luminosity, a very large ratio of infrared-to-optical luminosity, warm dust emission, a ratio of infrared-to-radio flux densities consistent with other infrared galaxies, and an optical spectrum similar to a Seyfert 2 galaxy. IRAS F15307+3552 shares these characteristics and its radio-to-optical spectral energy distribution with two other infrared galaxies, F10214+4724 and P09104+4109. Discovery of a third object with these properties defines an extreme subclass of ultraluminous galaxies powered primarily by star formation. The systematic method used to find this object begins the process of determining the space density of these most luminous examples of the infrared galaxy phenomenon.

IRAS F10214 + 4724 - an extended CO emission source at Z = 2.2867

Using the IRAM 30 m telescope, we observed CO(J=3-2) and CO(J=4-3) emission lines at z=2.2867 from the gas-rich protogalaxy IRAS F10214+4724. We estimate the molecular mass to be 3×10 11 h −2 <M(H 2 )/M ⊙ <3×10 12 h −2 and the gas-to-dust mass ratio as 1500<M(H 2 )/M d <15,000

ALMA Resolves the Nuclear Disks of Arp 220

We present 90 mas (37 pc) resolution ALMA imaging of Arp 220 in the CO (1-0) line and continuum at

CONTINUUM OBSERVATIONS AT 350 MICRONS OF HIGH-REDSHIFT MOLECULAR EMISSION LINE GALAXIES

\lambda = 2.6

Forbidden C I emission at Z = 2.286 in the protogalaxy IRAS F10214 + 4724

mm. The internal gas distribution and kinematics of both galactic nuclei are well-resolved for the first time. In the West nucleus, the major gas and dust emission extends out to 0.2\arcsec radius (74 pc); the central resolution element shows a strong peak in the dust emission but a factor 3 dip in the CO line emission. In this nucleus, the dust is apparently optically thick (

The discovery of a new massive molecular gas component associated with the submillimeter galaxy SMM J02399-0136.

\tau_{\rm 2.6mm} \sim1

Green Bank Telescope and the Millimeter Array

) at

CO at high redshifts

\lambda = 2.6

Comment on ''Anomalous hyperfine lines in formaldehyde in a dust cloud''

mm with a dust brightness temperature