
NICMOS ISR-2009-004: NICMOS Photometric Calibration Pipeline
We present the details of the NICMOS Photometric Calibration Pipeline used to generate
aperture photometry. We present an overview of the different corrections employed,
explain components of the pipeline and also outline the types of photometric and
statistical data products created. In de Jong et al. (in preparation) this photometry will
be used to determine the photometric calibration constants stored in the PHOTTAB
reference files.
A. C. Viana 29 Jun 2009 (pdf)
NICMOS ISR 2009-006: NICMOS Grism Wavelength Calibration
As part of the Cycle 16 NICMOS calibration program, new observations of planetary nebulae
were obtained using all three NICMOS grisms (G096, G141, and G206). The aim of these observations
was to re-derive the dispersion relations for the grism modes of NICMOS as well as to
examine and parametrize any field dependence of the dispersion relation within the field of view
of the instrument. In this ISR, we present updated versions of the dispersion relations of the
G096, G141, and G206 grisms. While the field dependence is small (1-2% peak to peak variation),
we also compute two dimensional polynomial solutions to compute more exact dispersion
relations anywhere in the field of view of NICMOS.
N. Pirzkal 26 Jun 2009 (pdf)
NICMOS ISR 2009-003: Updates to Calnica: Using Temperature
This report describes how the calnica data reduction software implements
temperature dependent reference files in order to correct for temperature dependent
variations in the dark current, the flat-fields, and the flux calibration. We describe in
detail the logic used by the software to decide when to apply a temperature dependent
correction and which temperature to use in that case.
T. Dahlen 26 Jun 2009 (pdf)
NICMOS ISR 2009-002: Temperature Dependent Dark Reference Files: Linear Dark and Amplifier Glow Components
This report describes the investigation of the temperature dependence of the linear dark
and amplifier glow components of the NICMOS temperature dependent *_tdd.fits
dark reference files in the post-NCS era, 2002-2008. We find a significant temperature
dependence of the amplifier glow signal with higher counts at higher temperature when
using the bias-derived detector temperature. The linear dark should also be dependent on
temperature, however, the expected change in dark current should to be smaller than the
scatter introduced from the read noise. This is consistent with what we find. We also
describe how the calnica reduction software uses the temperature dependent dark
components when calibrating NICMOS images.
T. Dahlen 08 Jun 2009 (pdf)
NICMOS ISR 2009-001: New Bad Pixel Mask Reference Files for the Post-NCS Era
The last determined bad pixel masks for the three NICMOS cameras were made in
September 2002. Those masks were created using data from calibration programs
following the installation of the NCS and are therefore based on the relatively limited
data set available at the time. Since then, the NICMOS calibration monitoring programs
have regularly obtained calibration images of both flat-fields and darks, images used to
create the mask reference files. With numerous images taken during a long base-line
(2002-2008), this data set allows us to create high signal-to-noise reference files, as well
as investigate any temporal dependence of the mask files. In this ISR we describe the
creation of new mask files based on this extended data set and compare the new masks
with the previous versions. The new masks created contain a higher number of bad
pixels compared to the old versions, while the number of pixels thought to be affected by
“grot” is lower.
E. Barker, T. Dahlen 08 Jun 2009 (pdf)
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