Discovery of three near infrared objects in CCD images of the Galactic Center

At visible wavelengths, the light of the Galactic Center is extinguished by a factor of ∠10¹² due to the absorbing matter along the 10 kpc path to the Sun. Thus, direct visible observations are not possible. However, at  far red  wavelengths (λ≳7000Å), the extinction declines dramatically, dropping to ∠10⁵ near a wavelength of 0.9μm. Recently, sensitive charge‐coupled devices (CCDs) have been developed with high quantum efficiency in the 0.9μm‐1.0μm range. On 1981 September 4/5 and 5/6, we used a CCD detector system (the ′′MASCOT′′) at the Cerro Tololo Inter‐American Observatory, to detect 3 extremely red objects in the direction of the Galactic Center which were not previously known. All three objects are <10′′ from the location of Sgr A West. If these objects do indeed lie at a distance of 10 kpc, then they are located within the innermost 1 pc of the Galaxy. One of these objects, designated NIR 1, lies within the extended 2.2μm infrared source IRS 16, which is thought to contain the dynamic center of Galaxy. Two interpretations which we consider for these three objects (NIR 1, NIR 2, and NIR 3) are that they are either tightly knit clusters of K5‐MO giant stars, or that they are extremely compact H II regions seen in the light of forbidden, doubly‐ionized sulfur. Further observational tests of these two hypotheses are suggested.