Lam CYLu JRUdalski ABond IBennett DPSkowron JMróz PPoleski RSumi TSzymański MKKozłowski SPietrukowicz PSoszyński IUlaczyk KWyrzykowski ŁMiyazaki SSuzuki DKoshimoto NRattenbury NJHosek Jr MWAbe FBarry RBhattacharya AFukui AFujii HHirao YItow YKirikawa RKondo IMatsubara YMatsumoto SMuraki YOlmschenk GRanc COkamura ASatoh YSilva SIToda TTristram PJVandorou AYama HAbrams NSAgarwal SRose STerry SK2023-11-122023-11-202020-07-062023-11-122023-11-202022-07-06Lam CY, Lu JR, Udalski A, Bond I, Bennett DP, Skowron J, Mróz P, Poleski R, Sumi T, Szymański MK, Kozłowski S, Pietrukowicz P, Soszyński I, Ulaczyk K, Wyrzykowski Ł, Miyazaki S, Suzuki D, Koshimoto N, Rattenbury NJ, Hosek MW, Abe F, Barry R, Bhattacharya A, Fukui A, Fujii H, Hirao Y, Itow Y, Kirikawa R, Kondo I, Matsubara Y, Matsumoto S, Muraki Y, Olmschenk G, Ranc C, Okamura A, Satoh Y, Silva SI, Toda T, Tristram PJ, Vandorou A, Yama H, Abrams NS, Agarwal S, Rose S, Terry SK. (2022). Supplement: "an Isolated Mass-gap Black Hole or Neutron Star Detected with Astrometric Microlensing" (. Astrophysical Journal, Supplement Series. 260. 2.0067-0049https://mro.massey.ac.nz/handle/10179/69190This supplement provides supporting material for Lam et al. We briefly summarize past gravitational microlensing searches for black holes (BHs) and present details of the observations, analysis, and modeling of five BH candidates observed with both ground-based photometric microlensing surveys and Hubble Space Telescope astrometry and photometry. We present detailed results for four of the five candidates that show no or low probability for the lens to be a BH. In these cases, the lens masses are <2 M ⊙, and two of the four are likely white dwarfs or neutron stars. We also present detailed methods for comparing the full sample of five candidates to theoretical expectations of the number of BHs in the Milky Way ( 1/4108).(c) The author/s CC BY 4.0https://creativecommons.org/licenses/by/4.0/Astrometry (80)Astrometric microlensing effect (2140)Astrophysical black holes (98)Stellar populations (1622)Journal article10.3847/1538-4365/ac74411538-4365journal-article55