Greybody factors for a minimally coupled massless scalar field in Einstein-Born-Infeld dilaton spacetime

We analyze in detail the propagation of a minimally coupled massless scalar field in the gravitational background of a four-dimensional Einstein-Born-Infeld dilaton charged black hole. We obtain analytical expressions for the absorption cross section as well as the decay rate for the scalar field in the aforementioned spacetime, and we graphically show its behavior for different values of the free parameters of the theory.

Figure 1

Effective potential versus $r$ for $l=1,\gamma =1,\mathrm{\Lambda }=0$, and for $M=1.1$ (solid black line), $M=1.75$ (dashed blue line), and $M=2.25$ (dot-dashed red line).

Figure 2

Same as in Fig. 1, but for $l=0$.

Figure 3

Reflection coefficient versus $\omega$ for $l=0$, $\mathrm{\Lambda }=0$, and from left to right $\gamma =0.5$, $\gamma =1$, and $\gamma =2$.

Figure 4

Reflection coefficient versus $\omega$ for $l=0$, $\gamma =1$, and from left to right $\mathrm{\Lambda }=0.1$, $\mathrm{\Lambda }=0.01$, and $\mathrm{\Lambda }=0.001$.

Figure 5

Absorption cross section as a function of $\omega$ for $l=0$ and for the same values of $\gamma$ and $\mathrm{\Lambda }$ as in Fig. 3.

Figure 6

Absorption cross section as a function of $\omega$ for $l=0$ and for the same values of $\gamma$ and $\mathrm{\Lambda }$ as in Fig. 4.

Figure 7

Decay rate as a function of $\omega$ for $l=0$ and for the same values of $\gamma$ and $\mathrm{\Lambda }$ as in Fig. 3. Note that the vertical axis is scaled as 1:${10}^{-3}$.

Figure 8

Decay rate as a function of $\omega$ for $l=0$ and for the same values of $\gamma$ and $\mathrm{\Lambda }$ as in Fig. 4. Note that the vertical axis is scaled as 1:${10}^{-3}$.