Composite Surveys

Available below are raw, interpolated, and moment-masked versions of a large (1.3 GB) FITS cube containing the entire CO archive: all longitudes, all velocities (± 320 km/s), and ± 30° of latitude. While this cube can be very useful for large-scale Galactic studies, one should keep in mind that the component surveys vary somewhat in sensitivity, gridding, and velocity coverage. In numerous cases interpolation was required to force individual surveys onto the common lbv grid. In general the individual CO surveys will provide slightly higher data fidelity.

The moment masked cube was not created directly from the raw cube, but rather is a composite of all the individual moment masked cubes. Each of these was "padded" with surrounding surveys before moment masking in order to avoid gaps in the composite cube between individual surveys owing to smoothing.


Whole Galaxy Cube (all l, b, v)
Dame, Hartmann, & Thaddeus (2001) ApJ, 547, 792

56 MB, 1.3 GB uncompressed
Raw: COGAL_all_raw.fits.gz
Raw Header: COGAL_all_raw.txt
Interpolated*: COGAL_all_interp.fits.gz
Moment masked: COGAL_all_mom.fits.gz


The very large cubes above are mainly empty, owing to the fact that the velocity spread of the emission is large only near the plane, and the latitude spread is large only near zero velocity. For these reasons, essentially all of the CO emission can be stored in two much smaller cubes, one restricted to a narrow latitude range (± 5° COGAL_deep.fits) and another restricted to a fairly narrow velocity range (± 35 km/s; COGAL_local.fits). The former is most useful for large-scale Galactic studies while the latter is best suited for studies of the solar neighborhood.


Whole Galaxy "Deep" Cube (restricted to ± 5° in b)
44 MB, 220 MB uncompressed
Raw: COGAL_deep_raw.fits.gz
Raw Header: COGAL_deep_raw.txt
Interpolated*: COGAL_deep_interp.fits.gz
Moment masked: COGAL_deep_mom.fits.gz


Whole Galaxy "Local" Cube (restricted to ± 35 km/s)
24 MB, 146 MB uncompressed
Raw: COGAL_local_raw.fits.gz
Raw Header: COGAL_local_raw.txt
Interpolated*: COGAL_local_interp.fits.gz
Moment masked: COGAL_local_mom.fits.gz


* In each spectrum, <= 2 missing channels are filled by linear interpolation. In each
spatial plane, single missing pixels are filled by linear interpolation, first in l direction, then b.



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