An infrared quintuplet near the Galactic center

Abstract

We present near-infrared broad-band images at K (λ = 2.23 μm), L' (μ = 3.75 μm), and M' (λ = 4.67 μm), and maps at L (λ = 3.5 μm), and N (λ = 10.2 μm) of a peculiar infrared quintuplet source along the line of sight toward the Galactic center Radio Arc. The five members have a very red energy distribution, 3.0 ≤ K-L' ≤ 4.7. Most likely the quintuplet complex is near the Galactic center, not merely a projection of foreground stars. The location of this group near a bright ridge structure in the "Radio Arc" suggests a possible association with that region. If the quintuplet is truly located close to the Galactic center, the sources have luminosities comparable to those of bright giants or supergiants, although they do not seem to be a cluster of OB- or M-type stars.