CO at $z=2.3$ in IRAS 10214+4724
Session 18 -- AGN Spectroscopy
Display presentation, Monday, 9, 1995, 9:20am - 6:30pm

## [18.04] CO at $z=2.3$ in IRAS 10214+4724

\def\CO#1#2{{\hbox {CO($#1\!\rightarrow\!#2$)}}} \def\,{\thinspace} \def\kms{km\thinspace s$^{-1}$} \def\Msun{M$_\odot$} \def\percc{cm$^{-3}$} \def\Htwo{{\hbox {H$_2$}}} S.~J.~E.~Radford (NRAO), P.~M.~Solomon (SUNY Stony Brook), D.~Downes (IRAM)

New observations of CO in IRAS 10214+4724 confirm the presence of large amounts of warm, dense molecular gas in a small source.

A new \CO32 spectrum from the 12\,m telescope shows a 250\,\kms\ wide line centered at $z=2.2855$. The line flux, $6\pm 1.5$\,Jy\,\kms, agrees with measurements at other telescopes (IRAM 30\,m and NRO 45\,m). This indicates the source must be small and dispels previous suggestions of missing flux or undetected components.

A new \CO32 map from the IRAM interferometer with $2''$ resolution shows the source size is $<2''$ and there is little, if any, evidence for a velocity gradient. In particular, the new map does not confirm the source extension indicated by an earlier, lower quality map.

A map of \CO65 from the OVRO interferometer with $2.5''$ resolution confirms the line flux measured with the IRAM 30\,m telescope and, hence, the high excitaiton of the molecular gas. This map also shows litte evidence for source extension or a velocity gradient.

The CO data imply 10214+4724 contains $10^{11}h^{-2}$\,\Msun\ of \Htwo\ at 5000\,\percc\ and 50\,K. The source size limit corresponds to $<8 h^{-1}$\,kpc, a typical galactic scale. Combined with the line width, this indicates the total mass is $< 1.3 \times 10^{11}/(\sin i)^2 \ h^{-1}$\,\Msun. Thus either a very large fraction of the galaxy's mass is molecular gas or the inclination is low.

The NRAO is operated by Associated Universities, Inc., under cooperative agreement with the National Science Foundation.