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NICMOS STScI Analysis Newsletter 19

NICMOS STScI Analysis Newsletter 19

September 1999

CONTENTS:


        - NICMOS NEWS
          + New NICMOS Information on the WWW
	  + New software tools on the web
	  + Synthetic Dark Image Generator
	  + NICMOS Histroy Tool

        - RECENT PREPRINTS

        - APPENDIX:  NICMOS CONTACTS

============================================================================  
				
				NICMOS NEWS
				-----------

New NICMOS Information on the WWW
---------------------------------

As with all Space Telescope instruments, the NICMOS home page is updated 
regularly. This page can be found from the STSCI home page 
(http://www.stsci.edu) by following the "Instruments" link.

Since the last STAN, the following ISRs have been published:

	ISR-99-008:  GROT in NICMOS Cameras
	(M. Sosey, E. Bergeron, September 20, 1999)

	ISR-99-007: NIC 2 Growth Curves 
	(S. T. Holfeltz & D. Calzetti, September 13, 1999) 

	ISR-99-006: NICMOS Coronagraphic Imaging Strategy 
	(A.B. Schultz, A.D. Storrs, and D. Fraquelli, August 27, 1999) 

	ISR-99-005: Camera 3 Intrapixel Sensitivity 
	(A. Storrs, R. Hook, M. Stiavelli, C. Hanley, 
	 W. Freudling, August 1999) 

	ISR-99-004: User's Guide to Polarimetric Imaging Tools 
	(Lisa Mazzuca & Dean Hines, August 2, 1999) 

	There is a new electronic distribution list for ISRs:
	+-----------------------------------------------------+
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	+-----------------------------------------------------+

New software tools on the web:
------------------------------

The following new software tools are now available on the web

	- Temperature-Dependent Dark Generator
	- Polarizer Data Analysis Software

see s/w tools page at following URL for info

http://www.stsci.edu/instruments/nicmos/NICMOS_tools/nicmos_tools.html
 

Synthetic Dark Image Generator
------------------------------
	by Brian Monroe

A new web tool has been made available to the public via the NICMOS webpage, 
which creates synthetic dark reference files based on temperature models 
achieved during the warm-up of NICMOS in late 1998/early 1999.  It can be found 
at http://www.stsci.edu/instruments/nicmos/NICMOS_tools/syndark.html.

The user fills out a form for which the required input is the camera, the 
temperature at which the observations were made, and the readout sequence which 
was used to obtain the data.  The web tool then manufactures the dark file and 
immediately returns a link to the new file so it can be downloaded. See the
on-line instructions for details.

The ability to manufacture temperature-specific darks has become necessary due 
to the sensitivity of NICMOS electronics to the small changes in temperature.  
The main feature which these new darks correct is the "shading" -- a detector 
bias which continually changes as the pixels are read out, resulting in a 
shadowed appearance of the data.  The new darks also contain an updated model 
of the true linear dark current.  The shading models were made by examining the 
behavior of the bias as NICMOS warmed from below 62 degrees to over 80 degrees  
K as the cryogen exhausted itself prematurely last winter.  They were made from 
dozens of images taken in a program specifically designed to monitor the darks 
as the instrument warmed up.  The linear dark current was also obtained from 
dozens of datasets in the same program.

Indications so far are that the new darks significantly improve both the 
problem of shading and pixel-to-pixel noise in the dark current.  The new 
tool in its current state only makes darks for NICMOS camera 2, where the
response of the detector to changes in temperature is the greatest. Soon
the tool will be updated in order to create darks for camera 1 and 3.


NICMOS History Tool
-------------------
	by Megan Sosey and Alex Storrs

Some parameters of interest in understanding NICMOS data are not currently
included in the data headers. Thus we have developed a new web tool for use 
with NICMOS data taken between January 7,1997 and January 31,1999. This 
tool allows observers determine the interpolated best focus, coronagraphic 
hole position, and plate scale for their observations. The tool also 
contains links to the new SAA tool, which provides information on South 
Atlantic Anomoly (SAA) passages preceding the observation, and a new 
attitude history tool, which provides plots of the solar elongation and 
off-nominal roll preceding an observation. This area is under development,
and suggestions are always welcome (write to storrs@stsci.edu).

The tool is on the "Instrument Status" link of the STScI NICMOS homepage:
http://www.stsci.edu/instruments/nicmos/nicmos_status.html

The SAA tool is also available as a standalone program. It uses 
a modified set of Science Mission Schedule (SMS) calendar files which 
contain the SAA entrance and exit times for the NICMOS SAA Avoidance 
Model (23). After entering each dataset's MJD start time (contained 
in the header keyword EXPSTART) the tool returns a plot detailing when 
each dataset started in relation to the last SAA passage.  A file is 
also returned which contains a listing of each input dataset's MJD start 
time, startime converted to decimal days from January 1 of that year, 
the time in minutes since the last saa exit, the duration of the last 
SAA passage and the SAA exit time in decimal days. Both the plots and 
the data file may be saved by the user for future reference. Further 
instructions on how to use the calculator and details about the output 
can be found on the startpage for the tool.
 
See: http://ra.stsci.edu/~sosey/saatool/nicmos_saatool.html

We are currently trying to incorporate these items automatically in the
NICMOS headers, but cycle 7 and cycle 7-NICMOS data will not have these
parameters. If they are of interest, please run the tool to determine
the proper values for interpreting your data.


=============================================================================

                         RECENT PREPRINTS
                         ----------------

We draw your attention to these papers, based on NICMOS 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.


MARTINI, P.; POGGE, R.W.  "Hubble Space Telescope
Observations of the CfA Seyfert 2s: the Fueling of Active
Galactic Nuclei"  AJ accepted

TREU, T.; STIAVELLI, M.  "A NICMOS Search for High Redshift
Elliptical Galaxy Candidates"  ApJ accepted

WEINBERGER, A.J.; BECKLIN, E.E.; SCHNEIDER, G.; SMITH,
B.A.; LOWRANCE, P.J.; SILVERSTONE, M.D.; ZUCKERMAN, B.;
TERRILE, R.J.  "The Circumstellar Disk of HD 141569 Imaged
with NICMOS"  ApJ accepted

CORBIN, M.R.; THOMPSON, R.I.; O'NEIL, E.; RIEKE, M.;
SCHNEIDER, G.  "High-Redshift Galaxies and QSOs in the
NICMOS Parallel Fields"  Photometric Redshifts and
High-Redshift Galaxies

FIGER, D.F.; KIM, S.S.; MORRIS, M.; SERABYN, E.; RICH,
R.M.; MCLEAN, I.S.  "HST/NICMOS Observations of Massive
Stellar Clusters Near the Galactic Center"  (paper preprint
not submitted; http://xxx.lanl.gov/abs/astro-ph/9906299)

FIGER, D.F.; MORRIS, M.; GEBALLE, T.R.; RICH, R.M.;
SERABYN, E.; MCLEAN, I.S.; PUETTER, R.C.; YAHIL, A.  "High
Resolution Infrared Imaging and Spectroscopy of the Pistol
Nebula: Evidence for Ejection"  (paper preprint not
submitted; http://xxx.lanl.gov/abs/astro-ph/9906479)

QUILLEN, A.C.; ALONSO-HERRERO, A.;RIEKE, M.J.; MCDONALD,
C.; FALCKE, H.; RIEKE, G.H.  "Dust Lanes Causing Structure
in the Extended Narrow Line Region of Early-Type Seyfert
Galaxies"  ApJ accepted

============================================================================

                     APPENDIX: NICMOS 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. If you do not know who these
persons are, you can find the information on the WWW at
http://www.stsci.edu/public/propinfo.html.

Analysis, STSDAS or any other HST-related questions can also be
addressed to help@stsci.edu.
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