Support #3131

Possible cause of error

Added by Acharyya Atreya about 1 year ago. Updated about 1 year ago.

Status:NewStart date:01/09/2020
Priority:NormalDue date:
Assigned To:Knödlseder Jürgen% Done:

50%

Category:-
Target version:-
Duration:

Description

I am running some ctools simulations for the CTA exgal working group. We are computing the pre-trial significance of 1550 AGN using ctools. When doing 50 hour simulations in the energy range 1-300 TeV I am encountering the following error

+++ WARNING in GCTABackground3D::mc(GEnergy&, GTime&, GRan&): Background rate 6.9329386163784e-08 for 196.515956506239 TeV at DETXY=[0.167020996035742,-0.113500638104345] is larger than the maximum expected rate 2.06984562822754e-08. Something is wrong with the code.

Code seems to be working for other analysis (have attached it here). Am worried about what it means.
Thanks in advance.

pl_simulations_50hr.py Magnifier (13.8 KB) Acharyya Atreya, 01/09/2020 12:58 PM


Recurrence

No recurrence.

History

#1 Updated by Tibaldo Luigi about 1 year ago

Hi Atreya,
could you please tell me:
  • which is the version of ctools you are using
  • for which IRFs you obtain this error message
  • what is the minimum energy (1 TeV)

#2 Updated by Acharyya Atreya about 1 year ago

Tibaldo Luigi wrote:

Hi Atreya,
could you please tell me:
  • which is the version of ctools you are using
  • for which IRFs you obtain this error message
  • what is the minimum energy (1 TeV)

Hi Luigi,

Am using :
Ctools version 1.6.3
The errors only occur for north sources having a declination >40
IRF prod 3b-v2 'South_z60_50h’ and 'North_z60_50h’ depending on declination

The minimum energy for this instance is 1 TeV upto a maximum of 199 TeV

Thanks

#3 Updated by Tibaldo Luigi about 1 year ago

Could you give me the coordinates of one of the sources for which you get the error please?

#4 Updated by Acharyya Atreya about 1 year ago

Tibaldo Luigi wrote:

Could you give me the coordinates of one of the sources for which you get the error please?

A possible source would be 4FGL_J0209.9+7229 32.4979 72.4877

I see what you mean. This source would not be detectable with CTA-S as below horizon (negative culmination). So it is possible then that this error arises due to that.
I had assumed that ctobssim would automatically handle that exception and give 0/'nan’ significance especially because I didn’t get same error for 5 hour simulations at all energy thresholds.
Thanks again

#5 Updated by Tibaldo Luigi about 1 year ago

No, it’s up to you to choose the array you want to run the simulation for. For this specific source you should choose CTA-N.
Can you please confirm whether you get this error for this source when you use a North IRF or if it is only when you use a South one?

#6 Updated by Acharyya Atreya about 1 year ago

Tibaldo Luigi wrote:

No, it’s up to you to choose the array you want to run the simulation for. For this specific source you should choose CTA-N.
Can you please confirm whether you get this error for this source when you use a North IRF or if it is only when you use a South one?

Yes it’s only when I run the South Array and a similar error also occurs for really Southern sources with North IRFs. Makes sense

I’ll manually alter my script to incorporate objects below horizon. They’d asked us to find pre-trial significances for both North and South arrays so I hadn’t done so yet.
Thanks so much and you’ve been a great help as usual.

#7 Updated by Tibaldo Luigi about 1 year ago

  • Tracker changed from Bug to Support
  • Assigned To set to Tibaldo Luigi
  • % Done changed from 0 to 50

You’re welcome.

TBD: figure out exactly what triggers this behavior, and, in case, implement a clearer error message.

#8 Updated by Tibaldo Luigi about 1 year ago

  • Assigned To changed from Tibaldo Luigi to Knödlseder Jürgen

I cannot figure out why dealing with an unreasonable ROI (below the horizon), raises this error. Jürgen, could you please take a look?

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