CN ZEEMAN OBSERVATIONS OF MOLECULAR CLOUD CORES

Citation
Rm. Crutcher et al., CN ZEEMAN OBSERVATIONS OF MOLECULAR CLOUD CORES, The Astrophysical journal, 456(1), 1996, pp. 217-224
Citations number
22
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
0004637X
Volume
456
Issue
1
Year of publication
1996
Part
1
Pages
217 - 224
Database
ISI
SICI code
0004-637X(1996)456:1<217:CZOOMC>2.0.ZU;2-W
Abstract
We present results from the first attempt to measure strengths of magn etic fields in dense molecular cloud cores by observations of the Zeem an effect in the 3 mm lines of CN. The observations were made with the 30 m IRAM radio telescope with a new polarimeter constructed for this experiment. The two molecular cores which were observed are located a bout 3' north of Orion-KL (OMC-N4) and about 1' east of IRS 4 in S106 (S106-CN). From CN data for OMC-N4 and S106-CN, respectively, we estim ate cloud radii of 0.03 and 0.05 pc, masses of 10 and 22 M., and H-2 d ensities of 1.6 x 10(6) cm(-3). Our CN Zeeman results for the line-of- sight magnetic fields are B-los(OMC-N4) = +79 +/- 99 mu G and B-los(S1 06-CN) = -57 +/- 199 mu G. Hence, we did not detect magnetic fields. O ur upper limits for B-los are significantly less than field:strengths expected for assumption of internal motions at the Alfven speed, of a critical mass to magnetic flux ratio, or of virial equilibrium, but th e very small sample of clouds and the uncertainties in the \B\(Alfven) , \B\(critical), and \B\(virial) estimates preclude definite conclusio ns.