AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |
Back to Blog
Scitools Understand Tutorial3/25/2021
Text can be read and used as a data format by any programming.Examples might be simplified to improve reading and basic understanding.
Scitools Understand Tutorial Full Correctness OfTutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. While using this site, you agree to have read and accepted our terms of use. For some of the selections that we made with the data server and dont want to modify, we can use INDEF to instruct the tool to read those values from the data file header. There will be a network outage, Wednesday May 2, 2018 from 19:00 EDT - 23:59 EDT. All services, web sites, and systems that require access to the internet will be affected by this work. The HEASARC welcomes your participation in a brief survey to capture how users access and utilize HEASARC data, software, and services. The outcome(s) of this survey will be used to guide, prioritize, and plan our activities and development in the coming years. It contains 18 questions, generally takes just a few minutes to complete, and your answers will remain totally anonymous. The detection, flux determination and spectral modeling of Fermi LAT sources is accomplished by a maximum likelihood optimization technique, as described in the Cicerone (see also, e.g., Abdo, A. A. et al. 2009, ApJS, 183, 46 ). Scitools Understand Tutorial How To Use TheTo illustrate how to use the Likelihood software, this narrative gives a step-by-step description for performing a binned likelihood analysis. However, when analyzing data over short time periods (with few events), it is better to use the unbinned analysis. To perform an unbinned likelihood analysis see the Unbinned Likelihood tutorial. A technical document explaining weighted likelihood is available. ![]() You may choose to select your own data files, or to use the files provided within this tutorial. The exposure map must be recomputed if any change is made to the data selection or binning. This is a longer data set than is described in the Extract LAT Data tutorial. The region selection used in the data extraction step, which is conical, must fully contain the 3D counts map spatial boundary, which is square. We provide the user with the original event data files and the accompanying spacecraft file. In order to combine the two events files for your analysis, you must first generate a text file listing the events files to be included. Scitools Understand Tutorial Download All TheIf you do not wish to download all the individual files, you can skip to the next step and retrieve the combined, filtered event file. However, you will need the spacecraft file to complete the analysis, so you should retrieve that now.) To generate the file list, type. When analyzing point sources, it is recommended that you include events with high probability of being photons. To do this, you should use gtselect to cut on the event class, keeping only the SOURCE class events (event class 128, or as recommended in the Cicerone ). In addition, since we do not wish to cut on any of the three event types (conversion type, PSF, or EDISP), we will use evtype3 (which corresponds to standard analysis in Pass 7). The text file you made ( binnedevents.txt ) will be used in place of the input fits filename when running gtselect. The syntax requires that you use an before the filename to indicate that this is a text file input rather than a fits file. For this example, we consider the source class photons within our 15 degree region of interest (ROI) centered on the blazar 3C 279.
0 Comments
Read More
Leave a Reply. |