dhuppenkothen / clarsach Goto Github PK

A file provided to XSpectrum.__init__ might not have the associated arf and rmf file specified.

Need to read "fracexpo" column from the ARF for proper treatment of HETG data.

Will probably just attach this to XSpectrum._read_Chandra method

The .pi files produced by CIAO specextract do not have binning specified.

It is probably the same binning as that provided by ARF and RMF, but will look into it.

Either way, current version of clarsach will fail to load it.

I plan to write this into the XSpectrum class for cases when an ARF and RMF are not automatically loaded.

pha2 fils contain the spectrum information for HEG and MEG spectra for multiple orders up to m = +/- 3

The XSpectrum call needs an additional keyword, "row", to handle this file type.

We might want to consider making XSpectrum a subclass (?) of astropy.nddata. This will be helpful if we want astropy to include X-ray stuff in specutils.

Either way, it would be nice to store the fits table data itself in the object because there are other useful pieces of information (e.g. background) that are situational, but highly useful.

I have a silly request. Please feel free to say "no" because I don't want to step on toes.

I was wondering if we could rename "clarsach" to "harp" when it is eventually publicly released.

We could make up an acronym for HARP like "High energy Astrophysics Response Program" or "High energy ARF and RMF in Python"

In real data, does the "EXPOSURE" keyword in the ARF and the observation contain the same number? They don't for our simulated data, but I'm wondering if that's every true in real data or whether that's just a special case related to our simulations?

Background: I've been thinking of moving the multiplication of frac_exp and exposure into the apply_arf method of the ARF class rather than have it in the apply_response method in XSpectrum, but then I realized that this doesn't work for our simulations because the exposure of the observation and the ARF are not the same!

Since I've now figured out how to create flux spectra, it'd be useful to have a function that calculates spectra in photon flux units rather than counts units. This is just a reminder that I should add this function.

I downloaded some data from tgcat and found that the ARF and RMF bin units are in 'keV' while the PHA file is in 'angstroms'. I'm glad we included that warning.

Will likely just add a method to the XSpectrum class that switches bin_unit between angstrom and keV (and reverse the binning).

_load_arf function relies on "ENERG_LO" and "ENERG_HI". However, the "SPECRESP" field is not always in energy units.

For HETG data:
I think that the specresp field is listed backwards (in angstrom) order. I would recommend relying on "BIN_LO" and "BIN_HI" because it is more universal and will more likely reflect the order in which the SPECRESP field is listed.

OR we will need to account for units in the apply_arf function

I plan to implement this in the XSpectrum._read_chandra method