Disky Elliptical Galaxies and the Allegedly Over-Massive Black Hole in the Compact Massive “Es” Galaxy NGC 1271

Abstract

While spiral and lenticular galaxies have large-scale disks extending beyond their bulges, and most local early-type galaxies with 10 10 < M * /M < 2 × 10 11 contain a disk (e.g., ATLAS 3D ), the earlytype galaxies do possess a range of disk sizes. The edge-on, intermediate-scale disk in the 'disky elliptical' galaxy NGC 1271 has led to some uncertainty as to what is its spheroidal component. Walsh et al. reported a directly measured black hole mass of (3.09 M for this galaxy; which they remarked was an order of magnitude greater than what they expected based on their derivation of the host spheroid's luminosity. Our near-infrared image analysis supports a small embedded disk within a massive spheroidal component with M sph, * = (0.9 ± 0.2) × 10 11 M (using M * /L H = 1.4from Walsh et al.). This places NGC 1271 just 1.6-sigma above the near-linear M bh -M sph, * relation for early-type galaxies. Therefore, past speculation that there may be a systematic difference in the black hole scaling relations between compact massive early-type galaxies with intermediate-scale disks, i.e. ES galaxies such as NGC 1271, and early-type galaxies with either no substantial disk (E) or a large-scale disk (S0) is not strongly supported by NGC 1271. We additionally (i) show how ES galaxies fit naturally in the ('bulge'-to-total)-(morphological type) diagram, while noting a complication with recent revisions to the Hubble-Jeans tuning-fork diagram, (ii) caution about claims of over-massive black holes in other ES galaxies if incorrectly modelled as S0 galaxies, and (iii) reveal that the compact massive spheroid in NGC 1271 has properties similar to bright bulges in other galaxies which have grown larger-scale disks.

A Black Hole Mass Determination for the Compact Galaxy Mrk 1216

“…In particular, from the MGE descriptions of HST images (van den Walsh et al 2015) and the best-fit stellar mass-to-light ratios from dynamical models fit to AO observations , we measure total luminosities of L V = 1.7 × 10 10 L ⊙ and L H = 7.2 × 10 10 L ⊙ , and total stellar masses of 1.6 × 10 11 M ⊙ and 1.0 × 10 11 M ⊙ for NGC 1277 and NGC 1271, respectively. These values are similar to the total luminosities and masses reported by Emsellem (2013) for NGC 1277 and Graham et al (2016b) for NGC 1271. Graham et al (2016a) calculate a larger total luminosity for NGC 1277 based on modeling the 1D light profile, however their MGE model suggests a smaller total luminosity than the one adopted here (their MGE model has 43% less light than their 1D component analysis).…”

The SAMI Galaxy Survey: embedded discs and radial trends in outer dynamical support across the Hubble sequence

“…The SAMI Galaxy Survey stellar kinematic sample will double in size this year as the recently observed data are analysed and added to the existing sample. In a follow-up paper (Foster et al in prep), we explore radial tracks in the spin-ellipticity diagram (Graham et al 2016) to further investigate the link between visual structure and kinematics. The planned multi-object wide-field IFU spectrograph, HECTOR (Bryant et al 2016) on the Anglo-Australian Telescope is designed to have optimised radial coverage of the stellar kinematics out to at least 2Re.…”

Revealing Hidden Substructures in the MBH–σ Diagram, and Refining the Bend in the L–σ Relation

“…Elliptical galaxies are pressuresupported, spheroid-dominated galaxies with minimal rotation. Ellicular galaxies host an intermediate-scale (rotating) stellar disk within their spheroids (Liller 1966;Graham et al 2016a), while lenticular galaxies have a large-scale disk extending beyond their bulges (see Graham 2019a, for a detailed morphological classification grid). LTGs are spiral (Sp) galaxies with a bulge, a large-scale disk, and spiral arms.…”