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| GGGGGGG HH HH RRRRR SSS |
STScI | GG HH HH RR R SS | STAN - GHRS
Analysis | GG GGG HHHHHH RRRRR SS | Number 20
News | GG GG HH HH RR R SS | May 1997
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CONTENTS:
- NEW GHRS DOCUMENTATION
- RECENT PREPRINTS
- APPENDIX: GHRS CONTACTS
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NEW GHRS DOCUMENTATION
----------------------
We have completed the following Instrument Science Reports for
close-out GHRS calibrations. The reports have been posted to our web
page; we provide the abstracts below.
GHRS-ISR-081: "An Analysis of Pipeline Wavelength Calibrations for the
First-Order Gratings of the GHRS in Cycles 4 through 6."
This Report is based on the execution of the Side 2 calibration
proposals 5600, 6172 and 6898, and Side 1 calibration proposals 5542,
6171, and 6897 (Cycles 4, 5, and 6, respectively). Results indicate
that the default wavelength scale provided by the pipeline data
reduction system has not changed significantly with time during the
past three cycles.
GHRS-ISR-082: "Analysis of Detector Calibrations for the GHRS for Cycle
4, 5, and 6."
This report presents the analysis of GHRS D1 and D2 detector
calibrations encompassing Cycles 4, 5, and 6. Calibration tests
examined include: dark count measurements, focus checks, flat-field
count rates, sample mapping function, and line mapping function
tests. Additional flat-field data from Cycles 1 to 3 were processed
and displayed to demonstrate the continuing decreasing trend in the
flat-field lamps response. Results of these analyses indicate the
instrument has remained stable throughout the past three Cycles.
GHRS-ISR-084: "Implementation of a Background Count Rate Model for the
GHRS."
This document describes the implementation and usage of a background
count rate model for the GHRS detectors. The model uses geomagnetic
longitude and latitude to predict the background count rate at the
time of observation. The calculation uses a mean relation determined
for the FOS, scaled appropriately for Sides 1 and 2 of the GHRS.
Please note that the paper version of GHRS-ISR-084 that was issued was
missing Fig. 1, due to a technical problem. It has been restored in
the on-line PostScript version.
GHRS-ISR-085: "Redetermination of Sensitivity for Grating G140L."
This GHRS-ISR describes a re-determination of the sensitivity
function for grating G140L of the GHRS. This was done after it was
determined that the existing functions left significant and
systematic residual errors. Definitions of the sensitivity and
vignetting functions are provided, and the procedures used to derive
them are described and illustrated. Some intrinsic limitations are
described of the process of deriving sensitivity for the GHRS and for
the ultraviolet in general. New baseline sensitivity functions for
G140L, and ones that are time-dependent, have now been installed in
CDBS.
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RECENT PREPRINTS
----------------
We draw your attention to these papers, based on GHRS data, that will
appear in the next few months. This list includes all preprints
received by the STScI Library not yet published in the journals.
Please remember to include our Library in your preprint distribution
list.
HECKMAN, T.M.; LEITHERER, C. "Kinematics of the interstellar medium in
NGC 1705: implications for distant star-forming galaxies" AJ 7-97
LANDSMAN, W.; APARICIO, J.; BERGERON, P.; DI STEFANO, R.; STECHER,
T.P. "S 1040 in M67: a post-mass transfer binary with a helium core
white dwarf" ApJ 6-1-97
LANZ, T.; HUBENY, I.; HEAP, S.R. "Non-LTE line-blanketed model
atmospheres of hot stars. III. Hot subdwarfs: the sdO star, BD +75
deg. 325" ApJ accepted
SAVAGE, B.D.; SEMBACH, K.R.; LU, L. "Absorption by highly ionized
interstellar gas along extragalactic and galactic sight lines" AJ 6-97
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APPENDIX: GHRS Contacts
-----------------------
Any questions about the scheduling of your observations should be
addressed to your Program Coordinator. Post-Observation questions can
be addressed to your Contact Scientist.
Analysis, STSDAS or any other HST-related questions can also be
addressed to help@stsci.edu.
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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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