THE J(2)-J(1)-E-METHANOL TRANSITIONS FOR J-GREATER-THAN-OR-EQUAL-TO-12 IN ORION-KL

The first astronomical measurements of the J(k) = 12(2) - 12(1), 14(2) - 14(1), 15(2) - 15(1), 16(2) - 16(1), and 17(2) - 17(1) transitions of E type methanol are presented. Corrections to the line rest frequen cies are significant. A map of the averaged J = 15 to 17 lines shows t hat the emission arises from a region of 35 ''(delta) by similar to 20 ''(alpha) FWHP size, centered similar to 7 '' south, <2 '' west of th e Hot Core. This is the Methanol Emission Center; the most intense CH3 OH masers are 15 '' to the NW. The J greater than or equal to 12 profi les are adequately fitted with two gaussian velocity components with F WHP Delta upsilon(1/2) approximate to 0.8 km s(-1) and approximate to 3 km s(-1). For the wider component, our data give a rotational temper ature of similar to 100 K. Excitation calculations indicate that the J (2) - J(1) populations are inverted; the narrow velocity component in the J = 15 to 17 transitions may be a low gain maser.