Astron. Astrophys. 362, 635-645 (2000)

2. Observations

Using the submillimeter common user bolometer array SCUBA (Gear & Cunningham 1995) on the James Clerk Maxwell Telescope (JCMT) ¹, we obtained 450 µm and 850 µm maps of IRAS 00259+5625 (in CB 3) and IRAS 19433+2743 (in L 810) on 1997 December 18, and IRAS 05440+2059 (in CB 34) on 1998 February 15. These IRAS sources are among the brightest 100 µm sources associated with globules listed in the Clemens & Barvainis (1988) catalog. Our maps, covering at least 15 15 regions approximately centered on each IRAS source, represent 5-10% of the optical core regions within CB 3 and L 810 and more than half of the optical core of CB 34. Most of the members of the known near-infrared clusters associated with these large globules lie within the regions covered by our submillimeter maps. We reduced the submillimeter maps using the methods described in the SCUBA mapping cookbook (Sandell 1997). The final maps were calibrated in units of Jy beam^-1 from maps of Uranus and the secondary calibrators RAFGL 618 and RAFGL 2688 (Sandell 1994) ². We estimate that the 450 µm and 850 µm flux calibration errors are less than 30% and 15%, respectively. The submillimeter opacities at 450 µm and 850 µm were estimated from the sky dip meter located at Caltech Submillimeter Observatory, which provides opacity information at 1300 µm every 10 minutes. Our data were collected on nights with good atmospheric conditions when the 850 µm opacity was as low as 0.16, providing stringent upper limits for undetected sources at both 450 µm and 850 µm. In order to derive accurate positions, a nearby source of known position was observed before and after mapping each region. Consequently, the pointing uncertainties are less than 2 arcseconds in all maps.

SCUBA has 37 bolometers in the long (850 µm) wavelength array and 91 bolometers in the short (450 µm) wavelength array; the bolometers of each array are separated by approximately two beam widths in a hexagonal pattern. The half power beam width (HPBW) of SCUBA is 80 at 450 µm and 15" at 850 µm. Both arrays can be used simultaneously. We used the 850 µm + 450 µm filter combination in jiggle-map mode as described in Huard et al. (1999).

© European Southern Observatory (ESO) 2000

Online publication: October 24, 2000
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