cloudy-apec-combined

Cloudy generated models and their comparison with apec photon flux output.

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How to get started?

CLOUDY model generation

• Download and compile CLOUDY 17.03 version ¹. Have the cloudy_shared.exe and libcloudy.so in the working directory.

• Create an input condition file <file_name.in> for generating the models, eg, apec_compare.in and save diffuse and total emission in <file_name>.lin, with params ² like:

  CMB redshift 0. 
  sphere
  radius 150 to 151 linear kiloparsec
  abundances "allen73.abn"
  metals 0.3 linear
  hden -4 log
  ## constant temperature, T=0.5 keV linear
  coronal, T=2.3e7 K linear
  stop zone 1
  iterate convergence
  age 1e9 years
  save continuum "temp-2.lin" units keV no isotropic
  save diffuse continuum "temp-2-emm.lin" units keV no isotropic
  

• Run the CLOUDY model generators for various params:

  ./cloudy_shared.exe -r apec_compare

• Do this for multiple temperature and metallicities for comparison.

APEC model generation

If you have patomdb and apec installed ³, go ahead with the following steps:

• Load threeML ⁴ conda environment:

  conda activate threeML

• Open the jupyter notebook and import the PYATOMDB database:

  jupyter-notebook apec-test.ipynb

• Initialise the APEC module and choose the abundances, temperature (kT in keV), normalisation (K in EM units), redshift, metallicity:

  from threeML import *
  modapec = APEC()
  modapec.abundance_table='Allen'
  # input params
  modapec.kT.value       = 1.0   # keV temperature
  modapec.K.value        = 1e-2  # Normalization, proportional to emission measure
  modapec.redshift.value = 0.    # Source redshift
  modapec.abund.value    = 0.3   # The metal abundance of each element is set to 0.3 times the Solar abundance
  

• Create energy grid (sets the energy binning you are sampling) and call modapec for corresponding photon flux:

  energies = np.logspace(-1., 1.5, 2000) # Set up the energy grid ## energy resoultion
  modapec(energies) # gives the output spectrum in the enrgy bins provided
  

🔖Dependencies:

• apec-test.ipynb → jupyter notebook to compare cloudy generated emission with APEC photon flux
• apec_compare.in → input file for cloudy
• apec_compare.in → output file for cloudy
• <file_name.lin> → Variuous example files generated by CLOUDY (out-> $4 \pi \nu J_{\nu} (\rm erg/s/cm^{2})$ with different temperatures for fixed metallicity of 0.3 solar.
• <file_name-emm.lin> → Corresponding outputs of $\nu (keV)$ vs $4 \pi \nu j_{\nu} (\rm erg/s/cm^{3})$.

🎓 Collaborators: Alankar Dutta, Ritali Ghosh, Prof. Prateek Sharma.

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Footnotes

1. https://trac.nublado.org/wiki/DownloadLinks ↩

2. http://web.physics.ucsb.edu/~phys233/w2014/hazy1_c13.pdf ↩

3. https://threeml.readthedocs.io/en/stable/notebooks/APEC_doc.html ↩

4. https://threeml.readthedocs.io/en/stable/notebooks/installation.html ↩