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| STScI Analysis Newsletter (STAN)
| Cosmic Origins Spectrograph (COS)
|
|October 2013
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In this Newsletter we provide some updates of interest to
COS users.
Contents:
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New COS/FUV TDS Correction Produces More Accurate Fluxes
A new COS FUV time-dependent sensitivity (TDS) reference file
(x9h1254fl_tds.fits) has been delivered for use in the HST
Pipeline. Due to a significant flattening of the COS FUV
sensitivity decline over the last year, data taken after
November 1, 2012 have artificially high fluxes (up to 12%
for most settings) and should be re-retrieved from MAST
if the absolute flux calibration is a concern.
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New Flat-Field reference file (FLATFILE) for COS FUV
Recent analysis of the COS FUV flat field has led to an improved
correction for some of the deepest features seen in FUV
observations, and on September 18, 2013, a new COS FUV
FLATFILE was delivered to On the Fly Recalibration (OTFR).
Users, especially those with either G140L observations at both
lifetime positions or with science interests near the edges of
the FUVB detector (for data taken at lifetime position 2,
i.e., after July 23 2012), should re-retrieve their data
(archive.stsci.edu) in order to get an improved
correction for flat-field effects.
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| The Space Telescope Science Institute is operated by the
| Association of Universities for Research in Astronomy,
| Inc., under NASA contract NAS5-26555.
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