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import warnings
warnings.filterwarnings('ignore')
import sys
sys.path.append("../pcygni_profile/")
%matplotlib inline
This brief tutorial should give you a basic overview of the main features and capabilities of the Python P-Cygni Line profile calculator, which is based on the Elementary Supernova Model (ES) of Jefferey and Branch 1990.
Head over to github and either clone my repository (https://github.com/unoebauer/public-astro-tools) or download the Python file directly.
These are all standard Python packages and you should be able to install these with the package manager of your favourite distribution. Alternatively, you can use Anaconda/Miniconda. For this, you can use the requirements file shipped with the github repository:
conda-env create -f pcygni_env.ymlIf you want to interactively use this jupyter notebook, you have to install jupyter as well (it is part of the requirements file and will be installed automatically when setting up the anaconda environment). Then you can start this notebook with:
jupyter notebook pcygni_tutorial.ipnbThe following Python code snippets demonstrate the basic use of the tool. Just execute the following lines in an python/ipython (preferable) shell in the directory in which the Python tool is located:
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import matplotlib.pyplot as plt
Import the line profile calculator module
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import pcygni_profile as pcp
Create an instance of the Line Calculator, for now with the default parameters (check the source code for the default parameters)
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profcalc = pcp.PcygniCalculator()
Calculate and illustrate line profile
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fig = profcalc.show_line_profile()
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import astropy.units as units
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import astropy.constants as csts
Now, we have a look at the parameters of the line profile calculator. The following code line just shows all keyword arguments of the calculator and their default values:
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tmp = pcp.PcygniCalculator(t=3000 * units.s, vmax=0.01 * csts.c, vphot=0.001 * csts.c, tauref=1,
vref=5e7 * units.cm/units.s, ve=5e7 * units.cm/units.s,
lam0=1215.7 * units.AA, vdet_min=None, vdet_max=None)
t: time since explosion (default 3000 secs)vmax: velocity at the outer ejecta edge (with t, can be turned into r) (1% c)vphot: velocity, i.e. location, of the photosphere (0.1% c)vref: reference velocity, used in the density law (500 km/s)ve: another parameter for the density law (500 km/s)tauref: reference optical depth of the line transition (at vref) (1)lam0: rest frame natural wavelength of the line transition (1215.7 Angstrom)vdet_min: inner location of the detached line-formation shell; if None, will be set to vphot (None)vdet_max: outer location of the detached line-formation shell; if None, will be set to vmax (None)Note that you have to supply astropy quantities (i.e. numbers with units) for all these parameters (except for the reference optical depth).
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fig = plt.figure()
ax = fig.add_subplot(111)
for t in [1, 10, 100, 1000, 10000]:
tmp = pcp.PcygniCalculator(tauref=t)
x, y = tmp.calc_profile_Flam(npoints=500)
ax.plot(x.to("AA"), y, label=r"$\tau_{{\mathrm{{ref}}}} = {:f}$".format(t))
ax.set_xlabel(r"$\lambda$ [$\mathrm{\AA}$]")
ax.set_ylabel(r"$F_{\lambda}/F^{\mathrm{phot}}_{\lambda}$")
ax.legend(frameon=False)
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The stronger the line, the deeper the absorption throughs and stronger the emission peak becomes. At a certain point, the line "staurates", i.e the profile does not become more prominent with increasing line strength, since all photons are already scatterd.
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fig = plt.figure()
ax = fig.add_subplot(111)
vmax = 0.01 * csts.c
for v in [0.5 * vmax, vmax, 2 * vmax]:
tmp = pcp.PcygniCalculator(tauref=1000, vmax=v)
x, y = tmp.calc_profile_Flam(npoints=500)
ax.plot(x.to("AA"), y, label=r"$v_{{\mathrm{{max}}}} = {:f}\,c$".format((v / csts.c).to("")))
ax.set_xlabel(r"$\lambda$ [$\mathrm{\AA}$]")
ax.set_ylabel(r"$F_{\lambda} / F^{\mathrm{phot}}_{\lambda}$")
ax.legend(frameon=False)
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fig = plt.figure()
ax = fig.add_subplot(111)
vphot = 0.001 * csts.c
for v in [0.5 * vphot, vphot, 2 * vphot]:
tmp = pcp.PcygniCalculator(tauref=1000, vphot=v)
x, y = tmp.calc_profile_Flam(npoints=500)
ax.plot(x.to("AA"), y, label=r"$v_{{\mathrm{{phot}}}} = {:f}\,c$".format((v / csts.c).to("")))
ax.set_xlabel(r"$\lambda$ [$\mathrm{\AA}$]")
ax.set_ylabel(r"$F_{\lambda} / F^{\mathrm{phot}}_{\lambda}$")
ax.legend(frameon=False)
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fig = plt.figure()
ax = fig.add_subplot(111)
tmp = pcp.PcygniCalculator(tauref=1000)
x, y = tmp.calc_profile_Flam(npoints=500)
ax.plot(x.to("AA"), y, label=r"no detached line-formation shell")
tmp = pcp.PcygniCalculator(tauref=1000, vdet_min=0.0025 * csts.c, vdet_max=0.0075 * csts.c)
x, y = tmp.calc_profile_Flam(npoints=500)
ax.plot(x.to("AA"), y, label=r"detached line-formation shell")
ax.set_xlabel(r"$\lambda$ [$\mathrm{\AA}$]")
ax.set_ylabel(r"$F_{\lambda} / F^{\mathrm{phot}}_{\lambda}$")
ax.legend(frameon=False)
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The detachment of the line-formation region leads to a "flat-top" line profile.