Observations of Bright Galactic Clouds

The following table lists a number of bright sources in the Galactic plane which are viable polarimetry targets, due to the high brightness of the sources. One way to choose which of these sources is most likely to give high polarization is to check what the inclination of the sight-line to the galactic azimuthal direction is for each source. The results of this check are noted under Notes. If nothing is noted it can be assumed that there is no close alignment between sightline and azimuth. (The reason that we want to do this checking is that the field tends to run on parallel to the Galactic azimuthal direction for positions outside the nucleus.)

The coordinates are based on the 2000 equinox. The notes for each source will indicate whether the precession from the 1950 equinox (as originally listed) was done by Tom or by skyview.

Update 3/17/00 Precession errors for RCW 57 and NGC 6334 have been corrected.

Source	RA (2000)	Dec (2000)	Temperature	Peak intensity	t₃₀₀	Notes
NGC 6334	17 20 55.0	-35 46 05.7	20-30 K	1400 MJy/sr	2.2 hr	Coordinates given for the northern peak. Flux is 400 micron flux quoted from Gezari (1982). Precession from 1950 epoch done by Tom.
RCW 122	17 20 05	-38 57 48	35-60 K	740-260 MJy/sr	4.5 hr	Coordinates are for a 150 micron peak, which is about 30" from the peak taken from a 100 micron IRAS FITS image. Precession done by skyview.
RCW 108	16 40 00	-48 51 45	35-40 K	460-330 MJy/sr	6.5-12.5 hr	Coordinates are for a 150 micron peak, which is within 7" of the IRAS 100 micron peak. Skyview coordinates listed. I did a check on this source to verify that the formulae I was using gave the same results as turned out by skyview, which they did to within 5" in dec. The RA was within 0.1 sec between the two methods for determining precession.
RCW 57	11 11 49	-61 18 43	40 K	715 MJy/sr	1.5 hr	Coordinates are an average of 150 micron and 1 mm peaks, which agree well (within 20") with each other. The listed coordinates agree well with the IRAS 100 micron FITS file data. The skyview search lists coordinates for RCW 57 about 3/4 of a degree off of the listed coordinates, but is now suspected to be the coordinates of a nearby source, NGC 3603. Also note that the sightline to RCW 57 is more or less along the azimuthal direction for its position. Precession done by Tom.
RCW 36	08 59 01	-43 44 10	40 K	315 MJy/sr	20.3 hr	Coordinates are for a 150 micron peak, which agree well with the peak of the IRAS 100 micron FITS file. Note that the sightline to RCW 36 lies along the azimuth for its position. Precession done by skyview.
Carinae Nebula	10 45 03.6	-59 41 04.2	30-40 K	435-200 MJy/sr	4.3-21 hr	Coordinates are for Eta Carinae. There appears to be an area of several array footprints with a 100 micron intensity of at least 6000 MJy/sr in the Carinae Nebula surrounding Eta Carinae. Precession done by skyview.