Supermassive black holes and their host spheroids. II. The red and blue sequence in the M{sub BH}–M{sub *,SPH} diagram

Journal Article · Wed Jan 20 04:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/817/1/21· OSTI ID:22887121

Savorgnan, Giulia A. D.; Graham, Alister W. ^[1]; Marconi, Alessandro ^[2]; Sani, Eleonora ^[3]

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1. Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia)
2. Dipartimento di Fisica e Astronomia, Universitá di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy)
3. European Southern Observatory, Alonso de Cordova, Vitacura 3107, Santiago (Chile)

In our first paper, we performed a detailed (i.e., bulge, disks, bars, spiral arms, rings, halo, nucleus, etc.) decomposition of 66 galaxies, with directly measured black hole masses, M{sub BH}, imaged at 3.6 μm with Spitzer. Our sample is the largest to date and, for the first time, the decompositions were checked for consistency with the galaxy kinematics. We present correlations between M{sub BH} and the host spheroid (and galaxy) luminosity, L{sub sph} (and L{sub gal}), and also stellar mass, M{sub ∗,sph}. While most previous studies have used galaxy samples that were overwhelmingly dominated by high-mass, early-type galaxies, our sample includes 17 spiral galaxies, half of which have M{sub BH}<10{sup 7} M{sub ⊙}, and allows us to better investigate the poorly studied low-mass end of the M{sub BH}--M{sub ∗,sph} correlation. The bulges of early-type galaxies follow M{sub BH} ∝ M{sub ∗,sph}{sup 1.04±0.10} and define a tight red sequence with intrinsic scatter ϵ{sub (M{sub B{sub H|M{sub ∗{sub ,{sub s{sub p{sub h)}}}}}}}} = 0.43 ± 0.06 dex and a median M{sub BH}/M{sub ∗,sph} ratio of 0.68 ± 0.04%, i.e., a ±2σ range of 0.1%–5%. At the low-mass end, the bulges of late-type galaxies define a much steeper blue sequence, with M{sub BH} ∝ M{sub ∗,sph}{sup 2−3} and M{sub BH}/M{sub ∗,sph} equal to 0.02% at M{sub BH} ≈ 10{sup 6} M{sub ⊙}. We additionally report that (1) our Sérsic galaxy sample follows M{sub BH} ∝ M{sub ∗,sph}{sup 1.48±0.20}, a less steep sequence than previously reported; (2) bulges with Sérsic index n{sub sph}<2, argued by some to be pseudo-bulges, are not offset to lower M{sub BH} from the correlation defined by the current bulge sample with n{sub sph}>2; and (3) L{sub sph} and L{sub gal} correlate equally well with M{sub BH}, in terms of intrinsic scatter, only for early-type galaxies—once reasonable numbers of spiral galaxies are included, the correlation with L{sub sph} is better than that with L{sub gal}.

• OSTI ID: 22887121
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 817; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BLACK HOLES
GALACTIC EVOLUTION
GALAXIES
GALAXY NUCLEI
LUMINOSITY
MASS
SUPERMASSIVE STARS