#!/usr/bin/env python
# coding: utf-8

# # Apparent angular size of astrophysical black holes

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version()


# We get some data from the `kerrgeodesic_gw` SageMath package:

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from kerrgeodesic_gw.astro_data import *


# 1 radian in microarcseconds:

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rad_muas = n(180/pi * 3600 * 1e6)
rad_muas


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1/rad_muas


# ## Sgr A*

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SgrA_mass_sol


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SgrA_distance_pc


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s = SgrA_mass_m / SgrA_distance_m
s


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s*rad_muas


# ## M87*

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M87_mass_sol


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M87_distance_pc


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s = M87_mass_m / M87_distance_m
s


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s*rad_muas


# ## Cyg X1

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CygX1_mass_sol = 15
CygX1_mass_m = CygX1_mass_sol * solar_mass_m 
CygX1_mass_sol


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CygX1_distance_pc = 1.86e3
CygX1_distance_m = CygX1_distance_pc * pc
CygX1_distance_pc 


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s = CygX1_mass_m / CygX1_distance_m
s


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s*rad_muas


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s*rad_muas*1e5


# ## M31*

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M31_mass_sol = 1.5e8
M31_mass_m = M31_mass_sol * solar_mass_m
M31_mass_sol 


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M31_distance_pc = 7.6e5
M31_distance_m = M31_distance_pc * pc
M31_distance_pc 


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s = M31_mass_m / M31_distance_m
s


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s*rad_muas


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