Search found 36 matches

by JeremySanders
Thu May 08, 2025 9:27 am
Forum: evtool
Topic: evtool failing when trying to merge event files
Replies: 7
Views: 60398

Re: evtool failing when trying to merge event files

Hi Brandon All radec2xy does is recalculate the X and Y coordinates to be centred on that position in the event file. By default, it should be the centre of the sky tile. If you'd like to make an image from the event file, then evtool is what you should use. It's a bit easier to use radec2xy to set ...
by JeremySanders
Wed May 07, 2025 5:41 pm
Forum: evtool
Topic: evtool failing when trying to merge event files
Replies: 7
Views: 60398

Re: evtool failing when trying to merge event files

Hi Brandon It's not very clear what you want to do. Can you explain what you want to achieve from the start? Why do you need to have an event file centred on a source? Is it for making images or source extraction? If your source covers multiple tiles, you'll need evtool to merge them. If you want to...
by JeremySanders
Wed Apr 16, 2025 5:08 pm
Forum: erbackmap
Topic: Process killed for large areas
Replies: 1
Views: 38875

Re: Process killed for large areas

Hi Jorge This seems like it ran out of memory to me. Is this Linux? If so, you could try running dmesg (may need sudo) and see whether the OOM Killer (out of memory killer) killed the process. If so, you'll need a machine with more memory or swap, or use smaller regions. It could also be quotas that...
by JeremySanders
Tue Dec 10, 2024 8:20 am
Forum: srctool
Topic: Annular Spectra
Replies: 1
Views: 50681

Re: Annular Spectra

Hi Jessica -

I'm off at the moment so can't check the code. I believe that it's only the model in the extraction region which matters. I think you can give a large source model with no problem. You can verify it yourself with a test case, however, and compare the ARFs/exposure.

Cheers

Jeremy
by JeremySanders
Tue Oct 22, 2024 9:58 am
Forum: expmap
Topic: "withweights" parameter effect
Replies: 7
Views: 64561

Re: "withweights" parameter effect

Dear Katharina Sorry for the delay. Ian's away at the moment, so I will reply. We've done some investigation to check that expmap is doing what we expect. The behaviour is * If withweights=yes, then the merged map is the effective on-axis exposure time that TM0 would have, no matter which TM modules...
by JeremySanders
Thu Aug 15, 2024 5:39 pm
Forum: srctool
Topic: Background Extraction with srctool
Replies: 1
Views: 19861

Re: Background Extraction with srctool

Hi Joe Yes, it's because the background spectra are accumulated during the good time intervals (GTIs) of the source. The manual says Please note that by default any background region is extracted using the same GTIs as the source. If the source region is large, this means that only a limited part of...
by JeremySanders
Fri Jul 26, 2024 8:24 am
Forum: Data analysis
Topic: Noisy Spectrum
Replies: 4
Views: 36053

Re: Noisy Spectrum

PS In Xspec, I suggest the "setplot rebin" command to visualise spectra with low numbers of counts with low grouping. e.g. "setplot rebin 10 50", to rebin for display to S/N=10 and a max of 50 channels. This doesn't affect the fit, but allows you to visualise the fit.
by JeremySanders
Fri Jul 26, 2024 8:05 am
Forum: Data analysis
Topic: Noisy Spectrum
Replies: 4
Views: 36053

Re: Noisy Spectrum

You need to look at brighter sources to get better spectra! For very faint sources you will have to make some strong model assumptions, for example where you freeze your parameters or add strong priors. You might only get a flux depending on model. Take a look at this advice: https://asd.gsfc.nasa.g...
by JeremySanders
Fri May 03, 2024 12:50 pm
Forum: Data analysis
Topic: Effective area for flux estimate
Replies: 1
Views: 20857

Re: Effective area for flux estimate

Hi Matteo

If you're making merged exposure maps, the exposure time is the equivalent exposure for the *on-axis* combined eROSITA effective area.

You can take the effective area at a particular energy from the ARF file here: https://erosita.mpe.mpg.de/dr1/eSASS4DR ... R1_arfrmf/

Cheers

Jeremy
by JeremySanders
Thu Apr 25, 2024 1:55 pm
Forum: srctool
Topic: Radial Profiles with srctool
Replies: 2
Views: 26257

Re: Radial Profiles with srctool

Dear Joe I would need to see a more complete description of how you are using srctool to understand the problem better. However, I can give some comments: The exposure time given by srctool isn't the same as in exposure maps - it is more of an on-time. See the docs. I would not use the rates from sp...