One of the features of the ETC is its ability handle a spectrum supplied by the user. In this version of the ETC this is accomplished by a direct upload from the machine where the user is running the web browser.
To use this option, you will need to:
The file will be uploaded when you click the “submit” button at the top or bottom of the form. If the file is large or the computer has a slow internet connection it will take extra time for the browser to send the file to the ETC server.
Prepare your input spectrum file with 2 columns:
Column 1 should be the wavelength in and column 2 should be the flux density (in for point sources, and in for diffuse sources).
The user specified spectrum file should be in one of the following 2 file formats:
Try to use a unique filename for this file, for example by using your last name as part of the filename.
If the file is an ASCII file, it must contain the following 2 columns:
column 1: wavelength (in )
in for diffuse sources
Any comment lines in the file must start with # in order to avoid confusion when it is used in the calculation.
The SDAS table file format is not portable to different machine architectures and so support for it has been discontinued. We recommend using the TTools command “tcopy” to convert all SDAS files to FITS format.
If the file is a FITS binary table, it should have two columns labeled “WAVELENGTH” and “FLUX”, again with the units specified for each column. The header of the FITS table should then include lines similar to these:
PCOUNT = 0 / GCOUNT = 1 / Only one group TFIELDS = 2 / Number of fields per row EXTNAME = 'f4v_v15_flam.tab' / Name of extension TTYPE1 = 'WAVELENGTH' / TBCOL1 = 1 / TFORM1 = 'E15.7 ' / TUNIT1 = 'angstroms' / TDISP1 = 'G15.7 ' / %15.7g TTYPE2 = 'FLUX ' / TBCOL2 = 17 / TFORM2 = 'E15.7 ' / TUNIT2 = 'flam ' / TDISP2 = 'G15.7 ' / %15.7g
In section 3 of the ETC input form, simply check the box next to “User Supplied Spectrum”. You may then either type the path of the file in the input box, or use the “browse” button next to the box and then navigate through the local file system to the file.