Spitzer Documentation & Tools
IRS Instrument Handbook

6.3.4             Level 2 (Post-BCD) Data

The products that come from combining Level 1 data are called Level 2, or post-BCD, or PBCD data. Table 6.7 is a list of the PBCD files delivered by the Spitzer Heritage Archive. Figure 6.2 is a cartoon illustrating the relationship between these files.

 

 

Table 6.7 PBCD Files Delivered.

Name

Description

Format

Channel (b)

Type (c)

Size (kb)

2dcoad.txt

List of coadd weights.

ASCII

0,1,2,3

A

< 1

bkmsk.fits

Mask file for bksub.fits.

128 128

16-bit int

0,2

P

< 37

bkspc.fits

Coadded, nod-subtracted spectrum, in Jy. See tablenote (a).

32-bit real

0,2

A

25

bksub.fits

For the low-resolution modules in Staring Mode, the co-added products of one nod are subtracted from those of the other to produce a sky-subtracted image (bksub.fits). This file (and bksub.tbl) should be treated with caution if the area is crowded or contains extended emission around the science target.

128 128

32-bit real

0,2

A

< 90

bksub.tbl

Coadded, nod-subtracted spectrum in Jy. This file (and bksub.fits) should be treated with caution if the area is crowded or contains extended emission around the science target. See tablenote (a).

ASCII

0,2

P

< 30

bkunc.fits

Uncertainty file for bksub.fits.

128 128

32-bit real

0,2

P

< 67

c2msk.fits

Mask file for coa2d.fits.

128 128

16-bit int

1,2,3,4

P

37

c2unc.fits

Uncertainty file for coa2d.fits.

128 128

32-bit real

0,1,2,3

P

67

coa2d.fits

In AORs with multiple cycles, DCEs at each telescope pointing are averaged to produce the coa2d.fits. The DCEs that contribute to each averaged product are listed in *inlist.txt.

128 128

32-bit real

0,1,2,3

P

< 90

ibsmk.txt

List of bmask files for coa2d.fits.

ASCII

0,1,2,3

A

< 1

inlst.txt

List of input files for coa2d.fits.

ASCII

0,1,2,3

A

< 1

out.pline

Output log.

ASCII

0,1,2,3

A

< 27

ridge.tbl

Extraction position table from bcd.fits or bksub.fits.

ASCII

0,2

A

< 57

tune.fits

Extracted spectrum from coa2d, in Jy. See tablenote (a).

32-bit real

0,1,2,3

A

25

tune.tbl

Extracted spectrum from coa2d, in Jy. See tablenote (a).

ASCII

0,1,2,3

P

< 134

xout.pline

Log files output from the extraction pipeline processing.

ASCII

0,1,2,3

A

< 15

(a) The data columns are: (1) spectral order, (2) wavelength in microns, (3) flux density in Janskys, (4) flux density uncertainty in Janskys, and (5) pixel status flag.

(b) 0=Short-Low (SL), 1=Short-High (SH), 2 = Long-Low (LL), 3 = Long-High (LH)

(c) P = Primary, A = Ancillary

 

Figure 6.2 Schematic relationship among PBCD files.