Constraint on Primordial Magnetic Fields In the Light of ARCADE 2 and EDGES Observations. (arXiv:2007.09938v3 [astro-ph.CO] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Natwariya_P/0/1/0/all/0/1">Pravin Kumar Natwariya</a>
We study the constraints on primordial magnetic fields (PMFs) in the light of
the Experiment to Detect the Global Epoch of Reionization Signature (EDGES)
low-band observation and Absolute Radiometer for Cosmology, Astrophysics and
Diffuse Emission (ARCADE 2). ARCADE 2 observation detected extra-galactic
excess radio radiation in the frequency range 3-90 GHz. The enhancement in the
radio radiation is also supported by the first station of the Long Wavelength
Array (LWA1) in the frequency range 40-80 MHz. The presence of early radiation
excess over the cosmic microwave background can not be completely ruled out,
and it may explain the EDGES anomaly. In the presence of decaying PMFs, 21 cm
differential brightness temperature can modify due to the heating of the gas by
decaying magnetic fields, and we can constraint the magnetic fields. For excess
radiation fraction ($A_r$) to be LWA1 limit, we show that the upper bound on
the present-day magnetic field strength, $B_0$, on the scale of 1 Mpc is
$lesssim 3.7$ nG for spectral index $n_B=-2.99$. While for $n_B=-1$, we get
$B_0lesssim1.1times10^{-3}$ nG. We also discuss the effects of first stars on
IGM gas evolution and the allowed value of $B_0$. For $A_r$ to be LWA1 limit,
we get the upper constraint on magnetic field to be
$B_0(n_B=-2.99)lesssim4.9times10^{-1}$ nG and
$B_0(n_B=-1)lesssim3.7times10^{-5}$ nG. By decreasing excess radiation
fraction below the LWA1 limit, we get a more stringent bound on $B_0$.
We study the constraints on primordial magnetic fields (PMFs) in the light of
the Experiment to Detect the Global Epoch of Reionization Signature (EDGES)
low-band observation and Absolute Radiometer for Cosmology, Astrophysics and
Diffuse Emission (ARCADE 2). ARCADE 2 observation detected extra-galactic
excess radio radiation in the frequency range 3-90 GHz. The enhancement in the
radio radiation is also supported by the first station of the Long Wavelength
Array (LWA1) in the frequency range 40-80 MHz. The presence of early radiation
excess over the cosmic microwave background can not be completely ruled out,
and it may explain the EDGES anomaly. In the presence of decaying PMFs, 21 cm
differential brightness temperature can modify due to the heating of the gas by
decaying magnetic fields, and we can constraint the magnetic fields. For excess
radiation fraction ($A_r$) to be LWA1 limit, we show that the upper bound on
the present-day magnetic field strength, $B_0$, on the scale of 1 Mpc is
$lesssim 3.7$ nG for spectral index $n_B=-2.99$. While for $n_B=-1$, we get
$B_0lesssim1.1times10^{-3}$ nG. We also discuss the effects of first stars on
IGM gas evolution and the allowed value of $B_0$. For $A_r$ to be LWA1 limit,
we get the upper constraint on magnetic field to be
$B_0(n_B=-2.99)lesssim4.9times10^{-1}$ nG and
$B_0(n_B=-1)lesssim3.7times10^{-5}$ nG. By decreasing excess radiation
fraction below the LWA1 limit, we get a more stringent bound on $B_0$.
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