J/MNRAS/446/2330 Overmassive black holes (Savorgnan+, 2015)
Overmassive black holes in the MBH-σ diagram do not belong to over
(dry) merged galaxies.
Savorgnan G.A.D., Graham A.W.
<Mon. Not. R. Astron. Soc., 446, 2330-2336 (2015)>
=2015MNRAS.446.2330S 2015MNRAS.446.2330S (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, peculiar ; Velocity dispersion
Keywords: black hole physics - galaxies: elliptical and lenticular, cD -
galaxies: evolution - galaxies: formation
Abstract:
Semi-analytical models in a Λ cold dark matter cosmology have
predicted the presence of outlying, 'overmassive' black holes at the
high-mass end of the (black hole mass-galaxy velocity dispersion)
MBH-σ diagram (which we update here with a sample of 89
galaxies). They are a consequence of having experienced more dry
mergers - thought not to increase a galaxy's velocity dispersion -
than the 'main-sequence' population. Wet mergers and gas-rich
processes, on the other hand, preserve the main correlation. Due to
the scouring action of binary supermassive black holes, the extent of
these dry mergers (since the last significant wet merger) can be
traced by the ratio between the central stellar mass deficit and the
black hole mass (Mdef,*/MBH). However, in a sample of 23 galaxies
with partially depleted cores, including central cluster galaxies, we
show that the 'overmassive' black holes are actually hosted by
galaxies that appear to have undergone the lowest degree of such
merging. In addition, the rotational kinematics of 37 galaxies in the
MBH-σ diagram reveals that fast and slow rotators are not
significantly offset from each other, also contrary to what is
expected if these two populations were the product of wet and dry
mergers, respectively. The observations are thus not in accordance
with model predictions and further investigation is required.
Description:
Our galaxy sample (see Table 1) consists of 89 objects for which a
dynamical detection of the black hole mass and a measure of the
stellar velocity dispersion have been reported in the literature. We
include in our sample all the 78 objects presented in the catalogue of
Graham & Scott (2013ApJ...764..151G 2013ApJ...764..151G), plus 10 objects taken from Rusli
et al. (2013AJ....146...45R 2013AJ....146...45R, Cat. J/AJ/146/45) and 1 object from
Greenhill et al. (2003ApJ...590..162G 2003ApJ...590..162G).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 105 89 Galaxy sample
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See also:
J/AJ/146/45 : Spectroscopy of 6 early-type galaxies (Rusli+, 2013)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Galaxy Galaxy name
10 A1 --- n_Galaxy [*] Note on Galaxy (1)
12- 18 F7.3 Mpc Dist Distance
20- 26 F7.3 10+8Msun MBH Black hole mass
28- 34 F7.3 10+8Msun E_MBH Error on MBH (upper value)
36- 42 F7.3 10+8Msun e_MBH Error on MBH (lower value)
45- 49 F5.2 10+8Msun MBHR ? For the 10 measurements taken from Rusli et
al. (2013, Cat. J/AJ/146/45), measurement
obtained without including in the modelling
the effects of dark matter
51- 53 I3 km/s sigma Stellar velocity dispersions
55- 56 I2 km/s e_sigma ? rms uncertainty on sigma
57 A1 --- --- [-]
58- 60 I3 km/s sigmaU ? Upper value of sigma when interval
62- 65 A4 --- Ref References of black hole mass and velocity
dispersion measurements reported here (2)
67- 70 A4 --- Core [yes/no? ] Presence of a partially depleted
core (3)
72- 75 A4 --- Bar [yes/no ?] Presence of a bar
76- 80 F5.1 10+8Msun Mdef1 ? Central stellar mass deficits as measured by
Rusli et al. (2013, Cat. J/AJ/146/45).
82- 86 F5.1 10+8Msun e_Mdef1 ? rms uncertainty on Mdef1
89- 91 I3 10+8Msun Mdef2 ? For seven galaxies we reconstructed the
'no-dark-matter' values (see Section 3.1)
94- 96 I3 10+8Msun Mdef3 ? Central stellar mass deficits as measured by
Dullo & Graham (2014MNRAS.444.2700D 2014MNRAS.444.2700D)
98-100 I3 10+8Msun e_Mdef3 ? rms uncertainty on Mdef3
102-105 A4 --- Class Kinematical classification (fast/slow rotator)
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Note (1): for the 18 galaxies marked with a *, the black hole masses were
estimated including in the modelling the effects of dark matter.
Note (2): References as follows:
G+03 = Greenhill et al., 2003ApJ...590..162G 2003ApJ...590..162G
R+13 = Rusli et al., 2013AJ....146...45R 2013AJ....146...45R, Cat. J/AJ/146/45
GS13 = Graham & Scott, 2013ApJ...764..151G 2013ApJ...764..151G
Note (3): The question mark is used when the classification has come from the
velocity dispersion criteria mentioned in Section 3.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 15-Jun-2015