Does the intermediate-mass black hole in LEDA 87300 (RGG 118) follow the near-quadratic MBH-MSpheroidRelation?
GRAHAM A.W., CIAMBUR B.C. and SORIA R.
Abstract (from CDS):
The mass scaling relation between supermassive black holes and their host spheroids has previously been described by a quadratic or steeper relation at low masses (105 < Mbh/M☉≲ 107). How this extends into the realm of intermediate-mass black holes (102 < Mbh/M☉< 105) is not yet clear, although for the barred Sm galaxy LEDA 87300, Baldassare et al. recently reported a nominal virial mass of Mbh= 5x104 M☉ residing in a ''spheroid'' of stellar mass equal to 6.3x108 M☉. We point out, for the first time, that LEDA 87300 therefore appears to reside on the near-quadratic Mbh-Msph,*relation. However, Baldassare et al. modeled the bulge and bar as the single spheroidal component of this galaxy. Here we perform a 3-component bulge+bar+disk decomposition and find a bulge luminosity which is 7.7 times fainter than the published ''bulge'' luminosity. After correcting for dust, we find that Mbulge= 0.9x108 M☉and Mbulge/Mdisk= 0.04–which is now in accord with ratios typically found in Scd-Sm galaxies. We go on to discuss slight revisions to the stellar velocity dispersion (40±11 km/s) and black hole mass (Mbh = 2.9–2.3+6.7 x 104f2.3 M☉) and show that LEDA 87300 remains consistent with the Mbh-σ relation, and also the near-quadratic Mbh-Msph,* relation when using the reduced bulge mass. LEDA 87300 therefore offers the first support for the rapid but regulated (near-quadratic) growth of black holes, relative to their host bulge/spheroid, extending into the domain of intermediate-mass black holes.
black hole physics - galaxies: elliptical and lenticular, cD - galaxies: individual: LEDA 087300 - galaxies: nuclei - galaxies: photometry - galaxies: structure