(4.4 \pm 0.2) \times 10^6 \nonumber \\
     & & \hskip -0.3in \left(
\frac{{\ensuremath{L_{5100}}}}{10^{44}~{\rm erg~
s^{-1}}} \right)^{0.64 \pm 0.02}~\left( \frac{{\ensuremath{\mathrm{FWHM}_\mathrm{H{\beta}}}}}{10^{3}~\mathrm{km~s^{-1}}} \right)^2 {\ensuremath{M_{\odot}}}.\end{aligned}$$

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Substituting Equations 1 and 3 into Equation 5, we obtain a virial mass formula that depends on the [H$\alpha$]{} line alone:

$$\begin{aligned}
{\ensuremath{M_\mathrm{BH}}}& = & (2.0 ^{+0.4}_{-0.3}) \times 10^6 \nonumber \\
     &   & \hskip -0.5in \left(
\frac{{\ensuremath{L_{\mathrm{H{\alpha}}}}}}{10^{42}~{\rm erg~s^{-1}}} \right)^{0.55 \pm 0.02}\left(
\frac{{\ensuremath{\mathrm{FWHM}_\mathrm{H{\alpha}}}}}{10^{3}~\mathrm{{km~s\ensuremath{^{-1}}}}} \right)^{2.06 \pm 0.06} {\ensuremath{M_{\odot}}}.\end{aligned}$$

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While we argue that [H$\alpha$]{} is the line of choice whenever possible, we recognize that often [H$\beta$]{} is more readily available (for instance, due to redshift constraints). In such cases, it might still be preferable to use [$L_{\mathrm{H{\beta}}}$]{} rather than [$L_{5100}$]{}, and for completeness we give the virial mass formula based only on the [H$\beta$]{} line:

$$\begin{aligned}
{\ensuremath{M_\mathrm{BH}}}&=& (3.6 \pm 0.2) \times 10^6 \nonumber \\
     & & \hskip -0.3in \left(
\frac{{\ensuremath{L_{\mathrm{H{\beta}}}}}}{10^{42}~{\rm erg~s^{-1}}} \right)^{0.56 \pm 0.02}~\left(
\frac{{\ensuremath{\mathrm{FWHM}_\mathrm{H{\beta}}}}}{10^{3}~\mathrm{{km~s\ensuremath{^{-1}}}}} \right)^2 {\ensuremath{M_{\odot}}}.\end{aligned}$$

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Comparison with Kaspi et al. (2005)
-----------------------------------

Kaspi [et al.]{} (2005) revisit the radius-luminosity relation for the reverberation-mapped sample, and we present a brief comparison of our respective results. Our best-fit [$R_{\mathrm{BLR}}$]{}-[$L_{5100}$]{} slope, 0.64 $\pm$ 0.02, is consistent with the result of Kaspi [et al.]{}, who find a best-fit slope of 0.67 