What is the difference between nifpmsel and niextract-events?

Overview

NICER provides several different ways to screen or filter event data. In particular, there are now two low-level tasks, nifpmsel and niextract-events, which performing screening.

Read this thread if you want to: What is the difference between nifpmsel and niextract-events?

Last update: 2021-07-19

Introduction

NICER provides several different ways to screen or filter event data. In particular, there are now two low-level tasks, nifpmsel and niextract-events, which performing screening.

Which to use? Each of these tasks is applicable in different situations.

niextract-events is used to merge event files and filter by time.

nifpmsel is used to screen event files by detector.

niextract-events is used to merge event files and filter by time

The task niextract-events is equivalent to the generic HEASoft task 'extractor', but with extra functionality specific to NICER. The task can be used to merge event files from multiple observations (or from different MPUs) into a single file. It can also be used to screen an event file via a user-supplied Good Time Interval (GTI) file.

Thus, if you want to make sure all data is "cleaned" according to a "clean" GTI, or if you want to combine multiple event files into one file, use niextract-events.

For more information, please see the niextract-events help file.

nifpmsel is used to screen by detector

Unlike niextract-events, nifpmsel is used to select or deselect certain requested detectors from an event file. This may be, for example, because a certain detector is noisy or not behaving properly. The task nifpmsel provides a way to deselect (remove) events from that detector, and properly account for it when generating response files.

For more information, please see the What is FPM Selection Information? and Screening Data with FPM Selections analysis threads, as well as the nifpmsel help file.

Modifications

• 2021-07-19 - initial draft