Response to Comment on “A noninteracting low-mass black hole─giant star binary system”

Van den Heuvel and Tauris argue that if the red giant star in the system 2MASS J05215658+4359220 has a mass of 1 solar mass (M☉), then its unseen companion could be a binary composed of two 0.9 M☉ stars, making a triple system. We contend that the existing data are most consistent with a giant of mass 3.2 − 1.0 + 1.0 M☉, implying a black hole companion of 3.3 − 0.7 + 2.8 M☉.