NICMOS STScI Analysis Newsletter 22
May 2000
CONTENTS:
- NICMOS NEWS
+ New NICMOS Exposure Time Calculator
+ Synthetic Darks for NIC1
- RELEASE OF THE VISUAL TARGET TUNER
- RECENT PREPRINTS
- APPENDIX: NICMOS CONTACTS
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NICMOS NEWS
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New NICMOS Exposure Time Calculator
-----------------------------------
Anand Sivaramakrishnan
During cryocooler operation of NICMOS (cycle 10), the detectors
in the camera will operate at significantly higher temperatures
than during the previous cycles when the detector was cooled with
solid nitrogen. This difference in operating temperature affects dark
current adversely, but improves the quantum efficiency (QE)
of the NICMOS detectors.
A new exposure time calculator (ETC) which incorporates the
detector behavior observed during the 'end of life' warm-up
of NICMOS is now available.
This ETC has a reworked thermal model for the HST OTA and NICMOS optics.
It also incorporates effects of cold pupil decentering and its concomitant
slight increase in thermal background in the longest wavelength NICMOS
bandpasses. The dominant sources of thermal background in these
filters are still the primary and secondary mirrors. The ETC uses
the STSDAS.SYNPHOT.COUNTRATE task as its throughput machine,
and throughput and quantum efficiency files from the Institute's
Calibration Data Base System (CDBS).
The ETC will soon be available at
http://www.stsci.edu/instruments/nicmos/NICMOS_tools/nicmos_tools.html
The NICMOS ISR 00-001 describes the ETC in more detail.
Synthetic Darks for NIC1
------------------------
Brian Monroe
The NICMOS Synthetic Dark web tool
http://www.stsci.edu/instruments/nicmos/NICMOS_tools/syndark.html
now supports multiaccum darks for camera 1. The magnitude of the shading error
is not as big as in camera 2, so visible improvements might not be as obvious.
However, pixel-to-pixel noise has been greatly reduced, so it is still worth
recalibrating.
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Release of the Visual Target Tuner
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Steve Lubow
With the June Call for Proposals, STScI will release a prototype
software tool called the Visual Target Tuner (VTT). The VTT was
originally developed as a proof of concept by a collaborating team
from NASA Goddard and STScI (aaaprod.gsfc.nasa.gov/SEA). This tool
displays HST apertures superimposed on sky images. The VTT provides
capabilities to import sky images, display primary and parallel
apertures, rotate apertures, centroid objects, specify excluded points
and regions, experiment with various orientations, and display catalog
overlays and object information. The tool can be useful for either
Phase 1 or Phase 2 of HST proposal preparation, although its main use
is likely to be for Phase 2.
In Phase 1, the tool can be used to answer questions such as: How many
fields will I need to mosaic my extended target? Which of my
potential targets "fits best" in the aperture? Is there anything
interesting I can pick up with a coordinated parallel in another
aperture? Do any of my potential targets have nearby bright objects
that could spoil the observation? Is there an orientation which would
avoid the bright object? (Note: this VTT release does not incorporate
moving target capabilities.)
The VTT is supported for use on the Solaris and Windows operating
systems. Further information about this tool will be available on the
"Proposing to Use HST" web page (www.stsci.edu/observing/proposing.html)
If you think you would benefit from a tool like this in either Phase 1
or Phase 2 we encourage you to download and try the software. The
feedback we receive this summer will play a role in determining our
priorities for the Phase 2 release in December.
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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.
DICKINSON, M. "Galaxy Evolution at 0 < z < 2 from the NICMOS
HDF-North," XIXth Moriond Astrophysics Meeting.
DICKINSON, M. "The First Galaxies: Structure and
Stellar Populations" Phil. Trans. Royal Soc. A
LUHMAN, K.L.; RIEKE, G.H.; YOUNG, E.T.; COTERA,
A.S.; CHEN, H.; RIEKE, M.J.; SCHNEIDER, G.;
THOMPSON, R.I. "The Initial Mass Function of
Low-Mass Stars and Brown Dwarfs in Young Clusters"
ApJ accepted
CHARY, R.; BECKLIN, E.E.; EVANS, A.S.; NEUGEBAUER,
G.; SCOVILLE, N.Z.; MATTHEWS, K.; RESSLER, M.E.
"High Resolution Infrared Imaging of the Compact
Nuclear Source in NGC 4258" ApJ 3-10-00
DAYAL, A.; LATTER, W.B.; BIEGING, J.; MEAKIN, C.;
KELLY, D.M.; HORA, J.L.; TIELENS, A.G.G.M.
"HST/NICMOS Observations of the Planetary Nebula
NGC 7027" Asymmetrical Planetary Nebulae II
HORA, J.L.; LATTER, W.B.; DAYAL, A.; BIEGING, J.;
KELLY, D.M.; TIELENS, A.G.G.M.; TRAMMELL, S.R.
"HST/NICMOS Imaging of the Planetary Nebula Hubble
12" Asymmetrical Planetary Nebulae II
LATTER, W.B.; DAYAL, A.; BIEGING, J.H.; KELLY,
D.M.; HORA, J.L.; TIELENS, A.G.G.M. "HST/NICMOS
Imaging of the Planetary Nebulae BD+30 degrees
3639" Asymmetrical Planetary Nebulae II
LATTER, W.B.; DAYAL, A.; BIEGING, J.H.; MEAKIN, C.;
HORA, J.L.; KELLY, D.M.; TIELENS, A.G.G.M.
"Revealing the Photodissociation Region: Hubble
Space Telescope/NICMOS Imaging of NGC 7027" ApJ
accepted
QUILLEN, A.C.; BOWER, G.A.; STRITZINGER, M. "A
NICMOS Survey of Early-Type Galaxy Centers: the
Relation Between Core Properties, Gas and Dust
Content and Environment" ApJS accepted
QUILLEN, A.C.; SHAKED, S.; ALONSO-HERRERO, A.;
MCDONALD, C.; LEE, A.; RIEKE, M.J.; RIEKE, G.H.
"The Variability of Seyfert 1.8 and 1.9 Galaxies at
1.6 Microns" ApJ 532: L17-L20, 2000
http://www.journals.uchicago.edu/cgi-bin/resolve?ApJv553pL17
BIEGING, J.H.; MEAKIN, C.A.; KELLY, D.M.; DAYAL,
A.; LATTER, W.B.; HORA, J.L.; TIELENS, A.G.G.M.
"HST/NICMOS Near-IR Imaging of the Proto-Planetary
Nebula OH 231.8+4.2" Asymmetrical Planetary Nebulae
2:
ZEPF, S.; LIU, M.C.; MARLEAU, F.R.; SACKETT, P.D.;
GRAHAM, J.R. "The Stellar Content of the Halo NGC
5907 from Deep HST NICMOS Imaging" AJ accepted
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APPENDIX: NICMOS Contacts
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Analysis, STSDAS or any other HST-related questions can be
addressed to help@stsci.edu.
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