HEASARC Staff Scientist Position - Applications are now being accepted for a Staff Scientist with significant experience and interest in the technical aspects of astrophysics research, to work in the High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA Goddard Space Flight Center (GSFC) in Greenbelt, MD. Refer to the AAS Job register for full details.
Appendix J: Glossary
- Component – A part of a model.
- Additive – A component which produces a theoretical spectrum.
- Multiplicative – A component which produces
multiplicative factors to apply to the current theoretical spectrum.
- Convolution – A component which modifies the current
theoretical spectrum
- Mixing – If there are multiple datasets with
separately calculated theoretical models this component modifies
all of them simultaneously.
- Datagroup – A set of observed spectra which will all be
fit using the same model and parameter values.
- Dataset – The observed spectrum and its associated information.
- Fit statistic – The statistic used to determine the
best fit value. The options are based on maximizing the likelihood.
- Model – The parameterized theoretical model for the
source spectrum. There is a default unnamed model but additional
named models can be defined.
- Plotgroup – A set of spectra which are summed together
for plotting purposes only.
- Response Model – A model which modifies the
response. At the moment this is limited to the gain.
- Source – In some observations several objects can
contribute to the same spectrum. In this case XSPEC refers to them as
different sources and each source can have its own model and response.
- Table Model – A model component stored as a FITS file
containing model spectra tabulated on a grid of parameter values.
- Test Statistic – The statistic to provide the
goodness-of-fit criterion after the parameters have been optimized
based on the fit statistic
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Last modified: Friday, 23-Aug-2024 13:20:40 EDT
HEASARC Staff Scientist Position - Applications are now being accepted for a Staff Scientist with significant experience and interest in the technical aspects of astrophysics research, to work in the High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA Goddard Space Flight Center (GSFC) in Greenbelt, MD. Refer to the AAS Job register for full details.
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