NICER Proposal Tools
The following documentation and applications can be used to
support the preparation of NICER observing proposals:
- NICER Mission Guide: The NICER team has developed a
NICER
Mission Guide document which describes NICER's technical
capabilities and concept of operations.
- Visibility: The standard HEASARC
Viewing tool
can be used to determine target visibilities for NICER based solely on Sun and Moon avoidance. The tool
reports a "preferred" visibility window, which has a Sun angle
constraint of 60-180 degrees, and a ``nominal'' visibility window,
which has a Sun angle constraint of 45-180 degrees. The Moon
avoidance angle is 15 degrees.
The NICER
Enhanced Visibility Calculator calculates visibilities for targets
over roughly the next 2-week period taking into account ISS orientation and target occultation by ISS structures, and other relevant constraints. These visibility intervals are more accurate than visibilities based solely on Sun and Moon avoidance.
- NICER Tips: Prospective proposers may wish to consult
this page
which provides NICER data analysis tips and caveats.
- Count Rate and Spectral Simulations:
The standard HEASARC count rate and spectral simulations
tools, WebPIMMS
and WebSpec, are available
for NICER simulations. They were updated in August 2019 to
include the most recent NICER responses and background files. It also
corrected a bug in the prior version that significantly overestimated
NICER's background rates in many circumstances.
- The NICER responses and background files can also be downloaded
directly by following the links below. These files can be used to
simulate spectra in spectral analysis software such as XSPEC. They are
suitable for the preparation of Cycle 2 proposals.
- Background Estimator Tools: The NICER team has developed
two
independent software packages to be used as add-ons to the
HEASoft software
that provide detailed models of the NICER background for a given
observation.
In addition, the NICER team has made available a set of files to assist users in
performing XSPEC analyses of NICER data.
- NICER Redistribution Matrix File (RMF).
- NICER Ancillary Response File (ARF).
- NICER Background PI: Example background spectral file.
- nixtiback20190807.pi
This file reproduces a "typical" NICER non-source count spectrum, including
particle-induced and cosmic diffuse X-ray background.
The background can deviate greatly from this typical spectrum, and can
do so to different degrees at low (<0.3 keV) and high energies,
depending on the details of the observation and the data screening
strategy that is applied.
Last Updated: July 28, 2021
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