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Proposal Identication No.: A1966 Date Received: 2004-Jun-01 08:46:39
Technical Page
Proposal Type: Regular
General Category: Astronomy
Sub-Category: Spectroscopy
Observation Category: Galactic
Total Time Requested: 8 Hours
Proposal Title: A survey of OH toward dark cloud cores observed by SWAS
ABSTRACT:
Oxygen is the third most abundant element in the interstellar space, and thus O-chemistry must be understood in
order to fully understand chemical proceesses in space. The Submillimeter Wave Astronomy Satellite (SWAS) has
detected spatially extended H 2 O emission from several giant molecular cloud cores, but only upper limits to the
water abundance could be established for three dark cloud cores (TMC-1, L134N and B335, Snell et al. 2000).
SWAS, however, failed to detect O 2 emission from the observed GMCs as well as the dark cloud cores. A tentative
detection was reported by Goldsmith et al. (2002) in the rho-Oph cloud core region (not observable from Arecibo).
The OH radical is a crucial intermediary in the Oxygen chemical network (Sternberg and Dalgarno 1995) and thus
the OH abundance can provide insight into the chemistry of O-bearing molecules. Here, we propose to observe the
2  3=2 J = 3=2 F = 1 2 (1612 ~
MHz), F = 1 1 (1665 ~
MHz), F = 2 2 (1667 ~
MHz) and F = 2 1 (1720 ~
MHz) OH
lines toward the three dark cloud cores observed by SWAS and also two well{studied regions: L1544, a pre{stellar
core, and NGC ~ 1333, an active site of low{mass star formation where shock chemistry is at work.
Name Institution E-mail Phone Student
Luca Olmi Institute of Radio
Astronomy
olmi@arcetri.astro.it +39-055-
2752214
no
Service Observing Request Remot e Observing Request
X None No
All of the observing run. X Maybe
Part of the observing run. Yes
Queue Observing
Instrument Setup
L-wide
Atmospheric Observation Instruments:
1

Special Equipment or setup: none
RFI Considerations
Frequency Ranges Planned
1605 - 1730
This proposal requires Iridium RFI protection at 1612 MHz between 10pm and 6am EST.
2