MATLAB: Difference between manually fitting data with a distribution and Histfit() function

Question

I'm trying to fit my time series data with a distribution. In the beginning, I used the function fitdist() to get the parameters and then used makedist() and pdf() to plot the histogram and pdf. However, the plot is a little bit different from the plot obtained with the function histfit(). Here's my code and plots (The left one is manual fitting while the right is plotted by function histfit()). Could anyone point out my mistakes? Is it due to the different scaling of y axis for the pdf?

a = n_rt(2:991);    % time series data
subplot(1,2,1)
yyaxis left
histogram(a, 20);    % histogram
yyaxis right
pd = fitdist(a', 'Gamma');    % fit the data with gamma distribution
pd2 = makedist('Gamma', pd.a, pd.b);    % make the pdf
y = pdf(pd2, 0.2:0.01:1.8);
y = y/sum(y);
plot(0.2:0.01:1.8, y, 'LineWidth', 2);
subplot(1,2,2)
histfit(a, 20, 'gamma');

Answer 1

"Is it due to the different scaling of y axis for the pdf?" Yes.