06/08/2009 Data Delivery SAGE LMC IRAC images
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IRAC 2.0" pixel 8x8 deg mosaics and mosaics of residual images of SAGE LMC
IRAC 1.2" pixel 8x8 deg mosaics and mosaics of residual images of SAGE LMC
IRAC 0.6" pixel 1.2x1.2 deg mosaic tiles of SAGE LMC
IRAC 0.6" pixel 0.9x0.6 deg mosaics of the SAGE LMC OFFSET position (centered at
RA=82.25 deg, Dec=-45.95 deg)
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These IRAC images were made from frames using SSC pipeline version S13.2
and later processing. Both SAGE LMC epochs of data were used in the
images. The images have been made at three pixel scales: 2", 1.2" (the
native resolution), and 0.6" pixel. The 12 second frametime IRAC
frames were mosaiced. The units are MJy/sr.
The 8x8 deg image filenames include the IRAC channel and pixel scale as
well as whether it is a mosaic or a residual image (e.g.
SAGE_LMC_IRAC4.5_2_mosaic.fits is the 8x8 deg 2" pixel band 2, 4.5 um
mosaic image; SAGE_LMC_IRAC8.0_1.2_resid.fits is the 8x8 1.2" pixel band 4
8.0 um residual image). The 0.6" pixel mosaic filenames give the IRAC
channel and tile number information. e.g. SAGE_LMC_IRAC3.6_tile45.fits is
the 1.2x1.2 deg 0.6" pixel band 1 3.6 um image centered at RA=79.70 deg,
Dec=-67.70 deg (see the table below for the tile centers). The SAGE LMC
Offset position filename is e.g. SAGE_LMC_OFF_IRAC5.8.fits.
The images have been corrected for column pulldown, banding, and muxbleed.
Outlier masking (using the improved outlier masking program IRACproc
(Schuster et al 2006, SPIE, 6270, 65)) has been done. Visual inspection
was done on the higher resolution 0.6" pixel mosaics. The instrument
artifacts found by this visual inspection were removed. Also, latent
images from bright sources were removed when possible. Note that the
instrument artifacts near the edge of coverage cannot be removed without
causing gaps in the images, because of little or no redundancy of
coverage. Montage's background matching was done for all 4 bands. The
gradient introduced because of the background matching was removed for the
8x8 deg images.
The residual images (images with the point sources removed) were produced
by running DAOPHOT on the IRAC BCD frames. These residual images are
mosaics of individual frame residuals. Thus, if a source is extracted in
some but not all frames it will show up in these images as a source
(although its brightness will be reduced because it is being averaged with
images where the source was extracted). Sources may not be extracted for a
variety of reasons, mainly due to cosmic ray contamination,
saturation/non-linearity limits and along the frame edges. Bands 1 and 2
residuals are always a bit worse than bands 3 and 4 due to the fact that
bands 1 and 2 are the more undersampled psfs of the 4 bands. Sources along
ridges and on complex background regions may be slightly over-extracted.
Close doubles are sometimes extracted as a single source. In these cases
the residual usually looks like a dark bar between two brighter lobes.
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The files in this data delivery are:
o README File:
SAGE_LMC_IMAGES_README_june2009 (this file)
o 2.0" pixel images - 8x8 deg
o 2.0" pixel mosaics of the 12 second FT data from both epochs
(1 GB per each fits file):
SAGE_LMC_IRAC3.6_2_mosaic.fits
SAGE_LMC_IRAC4.5_2_mosaic.fits
SAGE_LMC_IRAC5.8_2_mosaic.fits
SAGE_LMC_IRAC8.0_2_mosaic.fits
o 2.0" pixel mosaics of the residuals of the 12 second FT data from both epochs
(1 GB per file):
SAGE_LMC_IRAC3.6_2_resid.fits
SAGE_LMC_IRAC4.5_2_resid.fits
SAGE_LMC_IRAC5.8_2_resid.fits
SAGE_LMC_IRAC8.0_2_resid.fits
o 1.2" pixel images - 8x8 deg
o 1.2" pixel mosaics of the 12 second FT data from both epochs
(2.5 GB per file):
SAGE_LMC_IRAC3.6_1.2_mosaic.fits
SAGE_LMC_IRAC4.5_1.2_mosaic.fits
SAGE_LMC_IRAC5.8_1.2_mosaic.fits
SAGE_LMC_IRAC8.0_1.2_mosaic.fits
o 1.2" pixel mosaics of the residuals of the 12 second FT data from both epochs
(2.5 GB per file):
SAGE_LMC_IRAC3.6_1.2_resid.fits
SAGE_LMC_IRAC4.5_1.2_resid.fits
SAGE_LMC_IRAC5.8_1.2_resid.fits
SAGE_LMC_IRAC8.0_1.2_resid.fits
o 0.6" pixel images
o 1.2x1.2 deg 0.6" pixel mosaics of the 12 second FT data from both epochs
(<210 MB per file):
Below are listed the centers of the 1.2x1.2 deg 0.6" pixel tiles covering the
SAGE LMC survey region. The centers are offset 1.0 deg.
The tile# corresponds to the number shown in sagelmc_1.2x1.2_tiles.jpg. Note tiles 9,
38 & 85 are not used in any band (they are used in the MIPS mosaics). Tiles 10, 77 & 82
are not used in bands 2 & 4. Either there was no coverage or the coverage in that tile
was completely found in another tile. There are 82 bands 1 & 3 tiles and 79 bands 2 & 4
tiles. Images are projected to the common projection center: RA=79.7 deg, Dec=-68.7 deg.
1.2x1.2 deg tile numbers and tile centers:
Tile# RA (deg) Dec
1 93.21 -68.15
2 92.65 -67.18
3 92.13 -66.20
4 91.62 -70.31
5 91.08 -69.33
6 90.58 -68.35
7 90.12 -67.36
8 89.70 -66.38
9 89.32 -65.40 not used
10 89.66 -72.44 not used in bands 2 & 4
11 89.15 -71.46
12 88.70 -70.48
13 88.28 -69.49
14 87.90 -68.50
15 87.56 -67.51
16 87.24 -66.52
17 86.94 -65.53
18 86.76 -73.57
19 86.38 -72.58
20 86.03 -71.59
21 85.72 -70.60
22 85.44 -69.61
23 85.19 -68.61
24 84.96 -67.62
25 84.74 -66.62
26 84.54 -65.63
27 84.36 -64.63
28 83.24 -73.66
29 83.05 -72.67
30 82.88 -71.67
31 82.72 -70.67
32 82.58 -69.68
33 82.45 -68.68
34 82.33 -67.68
35 82.23 -66.68
36 82.13 -65.68
37 82.03 -64.69
38 81.95 -63.70 not used
39 79.70 -73.69
40 79.70 -72.69
41 79.70 -71.70
42 79.70 -70.70
43 79.70 -69.70
44 79.70 -68.70
45 79.70 -67.70
46 79.70 -66.70
47 79.70 -65.70
48 79.70 -64.71
49 79.70 -63.71
50 76.35 -72.67
51 76.52 -71.67
52 76.68 -70.67
53 76.82 -69.68
54 76.95 -68.68
55 77.07 -67.68
56 77.17 -66.68
57 77.27 -65.68
58 77.37 -64.69
59 77.45 -63.70
60 73.02 -72.58
61 73.37 -71.59
62 73.68 -70.60
63 73.96 -69.61
64 74.21 -68.61
65 74.44 -67.62
66 74.66 -66.62
67 74.86 -65.63
68 75.04 -64.63
69 75.21 -63.64
70 70.25 -71.46
71 70.70 -70.48
72 71.12 -69.49
73 71.50 -68.50
74 71.84 -67.51
75 72.16 -66.52
76 72.46 -65.53
77 72.73 -64.54 not used in bands 2 & 4
78 67.78 -70.31
79 68.32 -69.33
80 68.82 -68.35
81 69.28 -67.36
82 69.70 -66.38 not used in bands 2 & 4
83 64.92 -70.09
84 65.58 -69.12
85 66.19 -68.15 not used
o 0.9x0.6 deg 0.6" pixel mosaics of the SAGE LMC OFFSET position
(center: RA=82.25 deg, Dec=-45.95 deg)
SAGE_LMC_OFF_IRAC3.6.fits
SAGE_LMC_OFF_IRAC4.5.fits
SAGE_LMC_OFF_IRAC5.8.fits
SAGE_LMC_OFF_IRAC8.0.fits