NCSA Astronomy Digital Image Library
Project Abstract and Description
BIMA CO Observations of the Starburst Nucleus of M82
Jianjun Shen and K. Y. Lo
Contact: Jianjun Shen
Email: shenj@astro.uiuc.edu
Number of images in project: 2
References: 1995ApJ...445L..99S
Abstract
Observations with 2.5" (38 pc) resolution of the CO (J=1-0) emission
from the starburst nucleus of M82, obtained with the
Berkeley-Illinois-Maryland Association (BIMA) 6-element
millimeter-wave array, have revealed unresolved (< 30 pc) structure in
the CO emission with very high brightness temperature (up to 34
K). The new observations have also resolved the previously identified
double lobe and central peak in the integrated CO intensity into many
peaks that are all due to ``velocity crowding" of several velocity
components. Most of the CO emitting gas could be located in molecular
spiral arms at 125 pc and 390 pc from the nucleus. Outflow motion
(approximately 230 km/s) of part of the molecular gas normal to the
plane is also indicated. The new observations suggest that the
starbursts took place within molecular spiral arms at some distance
from the nucleus. The starbursts may in fact have propagated inwards.
Given the substantial amount of dense molecular gas still present in
the M82 starburst region, it is not clear why the starburst activity
appears to have subsided.
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