We present \lambda / \Delta \lambda = 550 to 1200 near infrared H 
and K spectra for a magnitude limited sample of 79 asymptotic giant branch and cool supergiant stars in the central \approx 5 pc ( diameter ) of the Galaxy .
We use a set of similar spectra obtained for solar neighborhood stars with known T _ { eff } and M _ { bol } that is in the same range as the Galactic center ( GC ) sample to derive T _ { eff } and M _ { bol } for the GC sample .
We then construct the Hertzsprung–Russell ( HRD ) diagram for the GC sample .
Using an automated maximum likelihood routine , we derive a coarse star formation history of the GC .
We find ( 1 ) roughly 75 \% of the stars formed in the central few pc are older than 5 Gyr ; ( 2 ) the star formation rate ( SFR ) is variable over time , with a roughly 4 times higher star formation rate in the last 100 Myr compared to the average SFR ; ( 3 ) our model can only match dynamical limits on the total mass of stars formed by limiting the IMF to masses above 0.7 M _ { \odot } .
This could be a signature of mass segregation or of the bias toward massive star formation from the unique star formation conditions in the GC ; ( 4 ) blue supergiants account for 12 \% of the total sample observed , and the ratio of red to blue supergiants is roughly 1.5 ; ( 5 ) models with isochrones with [ Fe/H ] = 0.0 over all ages fit the stars in our HRD better than models with lower [ Fe/H ] in the oldest age bins , consistent with the finding of Ramirez et al .
( 2000 ) that stars with ages between 10 Myr and 1 Gyr have solar [ Fe/H ] .