Publication Announcement: Supermassive Black Hole Mass Measurement in NGC 5102

I am pleased to announce that Korbin Waters’s latest paper, A Supermassive Black Hole Mass Measurement in NGC 5102 with Schwarzschild Orbit-superposition Modeling, has been officially published in ApJ. The paper addresses one of the gaps in our knowledge: the low-mass end of the black hole mass function. There, dynamical mass measurements are still rare enough that we don’t know what’s going on with the scaling relations.

Korbin measured the mass in NGC 5102 using data from the VLT/MUSE IFU and HST/STIS observations of the Ca II triplet and HST/WFPC2 F547M imaging. The mass measured is 1.3−0.18+0.19×106M⊙1.3^{+0.19}_{-0.18} \times 10^{6}\,M_{\scriptscriptstyle\odot} at an assumed distance of 3.66 Mpc.

What’s especially compelling about this result is the agreement between Korbin’s measurement and an earlier method using Jeans anisotropic modeling of the CO band heads.

Congratulations, Korbin!

This figure shows where the new measurement lands on the M–σeM–\sigma_{e} relation. NGC 5102 (orange) sits in the sparsely populated low-mass end, just above the nominal 10⁶ M⊙ boundary between supermassive and intermediate-mass black holes, and in close agreement with the earlier Nguyen et al. (2019) measurement of the same galaxy (teal). Both are consistent with an extrapolation of the Kormendy & Ho (2013) relation, which is anchored almost entirely by the far more numerous measurements at σe>100kms−1\sigma_e > 100\,\textrm{km}\,{\textrm{s}^{-1}}.
Two side-by-side blue-scale images of the lenticular galaxy NGC 5102, each overlaid with white contours of constant surface brightness and marked with north and east compass arrows and a 15-arcsecond scale bar. The left panel is a smaller, rotated high-resolution field showing a bright, mottled nucleus with visible dust structure. The right panel covers a wider field, showing the same galaxy as a smooth elliptical glow with concentric contours and a dark dust lane crossing just below the center.
NGC 5102 imaged with contours of constant surface brightness overlaid. The high-resolution HST view (left) resolves the dust and structure in the innermost region, while the wider MUSE field (right) traces the smooth, regular isophotes of the outer galaxy. Together they supply the light distribution that the dynamical models turn into a mass.