Date: Thursday August 27, 2009 14:49 PDT

Subject: Bug in S18.7 High-Resolution IRS Post-BCD Products, Legacy Program Data Deliveries

Contents:
1. Bug in S18.7 High-Resolution IRS Post-BCD Products
2. Spitzer LVL Legacy Program Enhanced Data Products Available
3. SAGE-Spectroscopy Legacy Program Enhanced Data Products Available


1. Bug in S18.7 High-Resolution IRS Post-BCD Products
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As part of the standard IRS post-BCD data processing, all the BCDs
associated with a given pointing are co-added. A bug in the pipeline
sometimes causes incorrect weights to be used in the co-addition for
S18.7 IRS high-resolution data.

The affected files are all found in the "pbcd" directory of data sets
downloaded from the Spitzer archive. Any of the co-added files
("coa2d.fits", "c2msk.fits", "c2unc.fits") may be incorrect. If a
"coa2d.fits" file is found to be incorrect, any files generated from
it will be also.  The affected files have the following suffixes:
"tune.fits", "tune.tbl". The BCDs are unaffected by this problem,
so these files can be used to extract spectra and/or assemble
spectral maps without cause for concern.

To determine if your data are affected, please examine the
"2dcoad.txt" files in the "pbcd" directory of your data set. The
first column of this file contains the weights used in the 
co-addition. The weights should all be close to unity. If you see 
low and/or negative weights, then your co-added files may be 
corrupted. 

As generally recommended, users are encouraged to construct their 
own co-adds before extraction. Alternatively, users can co-add 
1D spectra which have been extracted from the BCDs, which are 
unaffected by the bug.

The IRS team plans to reprocess all data in mid-2010, and this will
rectify the problem. In the meantime, if desired, users can create
their own "coa2d.fits" files by combining the appropriate "bcd.fits"
files. The associated 1D spectra can then be extracted using SPICE.
While it is possible to use a variety of software packages to create
the co-added images, we are providing an IDL procedure for this
purpose. This procedure, 'coad.pro', can be found at

http://ssc.spitzer.caltech.edu/postbcd/coad.html

If you have questions, please contact the Spitzer Helpdesk at:

http://sohelp2.ipac.caltech.edu/support/


2. Spitzer LVL Legacy Program Enhanced Data Products Available
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We have recently made available the latest Enhanced Data Products from 
the Local Volume Legacy (LVL) Spitzer Legacy program. The new delivery
consists of 256 galaxies for MIPS and 76 reprocessed archival galaxies 
for IRAC. Including all deliveries to date, now 256 LVL galaxies have 
IRAC and MIPS data. For 38 galaxies, additional 70 micron mosaics 
with values interpolated over low-weight pixels are provided. You can 
access the data via the team's data delivery web page at

http://ssc.spitzer.caltech.edu/legacy/lvlhistory.html

the Popular Products site at

http://data.spitzer.caltech.edu/popular/lvl/20090731_enhanced/

or through Leopard by performing a "Popular Products Query".


3. SAGE-Spectroscopy Legacy Program Enhanced Data Products Available
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We have recently made available the first Enhanced Data Products 
from the SAGE-Spectroscopy Spitzer Legacy program. The new delivery 
consists of IRS staring mode spectra of 197 sources, MIPS-SED 
spectra of 48 sources; postscript plots of the spectra, and SEDs 
of the sources. You can access the data via the team's data delivery 
web page at

http://ssc.spitzer.caltech.edu/legacy/sagespechistory.html

the Popular Products site at

http://data.spitzer.caltech.edu/popular/sage-spec/20090730_enhanced/

or through Leopard by performing a "Popular Products Query".


Spitzer Science User Support