Tour of hera_sim¶

This notebook briefly introduces some of the effects that can be modeled with hera_sim.

[8]:

%matplotlib inline
import numpy as np
import pylab as plt
import uvtools
from astropy.units import sday

from hera_sim import DATA_PATH

plt.rcParams["figure.figsize"] = [14, 8]

[10]:

from hera_sim import defaults, foregrounds, noise, rfi, sigchain

[12]:

defaults.set("h1c")
fqs = np.linspace(0.1, 0.2, 1024, endpoint=False)
lsts = np.linspace(0, 2 * np.pi, 10000, endpoint=False)
times = lsts / (2 * np.pi) * sday.to('s')
bl_len_ns = np.array([30.0, 0, 0])
h1c_beam = defaults("omega_p")(fqs)

Foregrounds¶

Diffuse Foregrounds¶

[13]:

Tsky_mdl = noise.HERA_Tsky_mdl["xx"]
vis_fg_diffuse = foregrounds.diffuse_foreground(
    lsts, fqs, bl_len_ns, Tsky_mdl=Tsky_mdl, omega_p=h1c_beam
)

[14]:

uvtools.plot.labeled_waterfall(vis_fg_diffuse, mode="log", freqs=fqs * 1e9, lsts=lsts)
uvtools.plot.labeled_waterfall(vis_fg_diffuse, mode="phs", freqs=fqs * 1e9, lsts=lsts);

../_images/tutorials_hera_sim_tour_8_0.png

../_images/tutorials_hera_sim_tour_8_1.png

Point-Source Foregrounds¶

[15]:

vis_fg_pntsrc = foregrounds.pntsrc_foreground(lsts, fqs, bl_len_ns, nsrcs=200)

[16]:

uvtools.plot.labeled_waterfall(vis_fg_pntsrc, mode="log", freqs=fqs * 1e9, lsts=lsts)
uvtools.plot.labeled_waterfall(vis_fg_pntsrc, mode="phs", freqs=fqs * 1e9, lsts=lsts);

../_images/tutorials_hera_sim_tour_11_0.png

../_images/tutorials_hera_sim_tour_11_1.png

Diffuse and Point-Source Foregrounds¶

[17]:

vis_fg = vis_fg_diffuse + vis_fg_pntsrc

[18]:

uvtools.plot.labeled_waterfall(vis_fg, mode="log", freqs=fqs * 1e9, lsts=lsts)
uvtools.plot.labeled_waterfall(vis_fg, mode="phs", freqs=fqs * 1e9, lsts=lsts);

../_images/tutorials_hera_sim_tour_14_0.png

../_images/tutorials_hera_sim_tour_14_1.png

Noise¶

[19]:

nos_jy = noise.sky_noise_jy(
    lsts, fqs, omega_p=h1c_beam, Tsky_mdl=noise.HERA_Tsky_mdl['xx']
)

[22]:

uvtools.plot.labeled_waterfall(nos_jy, mode="log", freqs=fqs * 1e9, lsts=lsts,
                               dynamic_range=2)
uvtools.plot.labeled_waterfall(nos_jy, mode="phs", freqs=fqs * 1e9, lsts=lsts);

../_images/tutorials_hera_sim_tour_17_0.png

../_images/tutorials_hera_sim_tour_17_1.png

[23]:

vis_fg_nos = vis_fg + nos_jy

[24]:

uvtools.plot.labeled_waterfall(vis_fg_nos, mode="log", freqs=fqs * 1e9, lsts=lsts,
                               dynamic_range=3)
uvtools.plot.labeled_waterfall(vis_fg_nos, mode="phs", freqs=fqs * 1e9, lsts=lsts);

../_images/tutorials_hera_sim_tour_19_0.png

../_images/tutorials_hera_sim_tour_19_1.png

RFI¶

[50]:

rfi1 = rfi.rfi_stations(lsts, fqs, stations=DATA_PATH / "HERA_H1C_RFI_STATIONS.npy")
rfi2 = rfi.rfi_impulse(lsts, fqs, impulse_chance=0.05, impulse_strength=1e6)
rfi3 = rfi.rfi_scatter(lsts, fqs, scatter_chance=0.01, scatter_strength=1e6)
rfi_all = rfi1 + rfi2 + rfi3

[51]:

uvtools.plot.labeled_waterfall(rfi_all, mode="abs", freqs=fqs * 1e9, lsts=lsts)
uvtools.plot.labeled_waterfall(rfi_all, mode="phs", freqs=fqs * 1e9, lsts=lsts);

../_images/tutorials_hera_sim_tour_22_0.png

../_images/tutorials_hera_sim_tour_22_1.png

[52]:

vis_fg_nos_rfi = vis_fg_nos + rfi_all

[53]:

uvtools.plot.labeled_waterfall(vis_fg_nos_rfi, mode="log", freqs=fqs * 1e9, lsts=lsts)
uvtools.plot.labeled_waterfall(vis_fg_nos_rfi, mode="phs", freqs=fqs * 1e9, lsts=lsts);

../_images/tutorials_hera_sim_tour_24_0.png

../_images/tutorials_hera_sim_tour_24_1.png

Gains¶

[54]:

g = sigchain.gen_gains(fqs, [1, 2, 3])
plt.figure()
for i in g:
    plt.plot(fqs, np.abs(g[i]), label=str(i))
plt.legend()
plt.show()

../_images/tutorials_hera_sim_tour_26_0.png

[58]:

vis_total = sigchain.apply_gains(vis_fg_nos_rfi, g, (1, 2))

uvtools.plot.labeled_waterfall(vis_total, mode="log", freqs=fqs * 1e9, lsts=lsts,
                               dynamic_range=6)
uvtools.plot.labeled_waterfall(vis_total, mode="phs", freqs=fqs * 1e9, lsts=lsts);

../_images/tutorials_hera_sim_tour_27_0.png

../_images/tutorials_hera_sim_tour_27_1.png

Crosstalk¶

[59]:

xtalk = sigchain.gen_whitenoise_xtalk(fqs)
if xtalk.ndim == 1:
    xtalk = np.reshape(xtalk, (1, -1))
vis_xtalk = vis_fg_nos_rfi + xtalk
vis_xtalk = sigchain.apply_gains(vis_xtalk, g, (1, 2))

[60]:

uvtools.plot.labeled_waterfall(vis_xtalk, mode="log", freqs=fqs * 1e9, lsts=lsts,
                               dynamic_range=6)
uvtools.plot.labeled_waterfall(vis_xtalk, mode="phs", freqs=fqs * 1e9, lsts=lsts);

../_images/tutorials_hera_sim_tour_30_0.png

../_images/tutorials_hera_sim_tour_30_1.png