Light curves from highly compact neutron stars with spot size effect. (arXiv:2002.11840v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Sotani_H/0/1/0/all/0/1">Hajime Sotani</a>
We systematically examine light curves from a single hot spot on a slowly
rotating neutron star with very high compactness, where the so-called invisible
zone does not exist. In particular, we adopt three different shapes of hot spot
and take into account the finite size effect of hot spot on the light curves.
Then, we find that the brightening of flux occurs when the hot spot with small
area crosses the opposite side to the observer, where the brightening becomes
stronger as the area of hot spot decreases. Since this brightening happens only
when a part of hot spot crosses the opposite side to the observer, one may
constrain the neutron star geometry, i.e., the combination of an inclination
angle, angle between the rotational axis and normal vector at the center of hot
spot, and the opening angle of hot spot, if the brightening would be observed.
In addition, by counting such a brightening in the light curves, one may know
how many narrow bands of hot spot and/or spots with small area cross the
opposite side to the observer.
We systematically examine light curves from a single hot spot on a slowly
rotating neutron star with very high compactness, where the so-called invisible
zone does not exist. In particular, we adopt three different shapes of hot spot
and take into account the finite size effect of hot spot on the light curves.
Then, we find that the brightening of flux occurs when the hot spot with small
area crosses the opposite side to the observer, where the brightening becomes
stronger as the area of hot spot decreases. Since this brightening happens only
when a part of hot spot crosses the opposite side to the observer, one may
constrain the neutron star geometry, i.e., the combination of an inclination
angle, angle between the rotational axis and normal vector at the center of hot
spot, and the opening angle of hot spot, if the brightening would be observed.
In addition, by counting such a brightening in the light curves, one may know
how many narrow bands of hot spot and/or spots with small area cross the
opposite side to the observer.
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