MULTIPLE CO TRANSITIONS, C-I, AND HCN FROM THE CLOVERLEAF QUASAR

New millimeter-wavelength emission lines are reported for the Cloverle af (H1413+117), a gravitationally lensed quasar at redshift 2.56. High signal-to-noise ratio (S/N) spectra of four lines in CO (3 --> 2, 4 - -> 3, 5 --> 4, and 7 --> 6) have been obtained and are modeled with an escape probability formalism. The line brightness temperatures are fl at or rising between CO (3 --> 2) and CO (4 --> 3) and then drop to th e CO (5 --> 4) and CO (7 --> 6) lines; this falloff suggests that the optical depths in the CO lines are modest (tau(4-3) less than or simil ar to 3) and that the gas is relatively warm (T greater than or simila r to 100 K) and dense (n(H2) greater than or similar to 3 x 10(3) cm(- 3)). The neutral carbon fine-structure line C I (P-3(1) --> P-3(0)) wa s detected with moderate S/N on two separate occasions and appears sec ure. The HCN (4 --> 3) line is somewhat more tentative, as it was obse rved only once and detected with moderate S/N. However, its brightness ratio relative to the CO (4 --> 3) line, L'(HCN)/L'(CO) approximate t o 0.25, is very similar to the ratio seen in luminous infrared galaxie s. This probably reflects the gas fraction maintained at high densitie s by radiation pressure from the active nucleus; alternatively, the HC N transition may be excited through absorption of infrared radiation a t 14 mu m. The detectability of the Cloverleaf in molecular and neutra l atomic transitions is largely due to high emissivity of the gas and magnification from gravitational lensing rather than an extremely larg e mass of gas.