J/A+A/612/L6 j-M law from dwarf to massive spirals (Posti+, 2018)
The angular momentum-mass relation: a fundamental law from dwarf irregulars to
massive spirals.
Posti L., Fraternali F., di Teodoro E. M., Pezzulli G.
<Astron. Astrophys. 612, L6 (2018)>
=2018A&A...612L...6P 2018A&A...612L...6P (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby; Stars, masses
Keywords: galaxies: kinematics and dynamics - galaxies: spiral -
galaxies: structure - galaxies: formation
Abstract:
In a {LAMBDA} CDM Universe, the specific stellar angular momentum (j*)
and stellar mass (M*) of a galaxy are correlated as a consequence of
the scaling existing for dark matter haloes (jh∝2/3). The
shape of this law is crucial to test galaxy formation models, which
are currently discrepant especially at the lowest masses, allowing to
constrain fundamental parameters, such as, for example, the retained
fraction of angular momentum. In this study, we accurately determine
the empirical j*-M* relation (Fall relation) for 92 nearby spiral
galaxies (from S0 to Irr) selected from the Spitzer Photometry and
Accurate Rotation Curves (SPARC) sample in the unprecedented mass
range 7≲logM*/M☉≲11.5. We significantly improve all previous
estimates of the Fall relation by determining j* profiles
homogeneously for all galaxies, using extended HI rotation curves, and
selecting only galaxies for which a robust j* could be measured
(converged j*(<R) radial profile). We find the relation to be well
described by a single, unbroken power-law j*αM*α over
the entire mass range, with α=0.55±0.02 and orthogonal
intrinsic scatter of 0.17±0.01dex. We finally discuss some
implications of this fundamental scaling law for galaxy formation
models and, in particular, the fact that it excludes models in which
discs of all masses retain the same fraction of the halo angular
momentum.
Description:
The table contains the estimates of the stellar masses and specific
angular momenta of 92 spiral galaxies in the SPARC sample (Lelli et
al., 2016, Cat. J/AJ/152/157). Estimates are given both for the whole
galaxy and only for its disc component, together with standard
uncertainties. Two flags on the quality of the measurements, assessing
whether the observed specific angular momentum profiles have reached
convergence (defined in Eq. 2 in the paper), are also provided.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 81 92 List of galaxy masses and specific angular momenta
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See also:
J/AJ/152/157 : Mass models for 175 disk galaxies with SPARC (Lelli+, 2016)
Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Galaxy Galaxy name (1)
14- 15 I2 --- T Hubble type (1)
17 I1 --- fD [1/5] Distance method (2)
19- 26 E8.2 Msun Mstar Galaxy's stellar mass (3)
28- 35 E8.2 Msun Mdisc Disc's stellar mass (3)
37- 44 E8.2 Msun e_Mstar Uncertainty on the stellar masses (3)
46- 53 E8.2 kpc.km/s jstar Galaxy's specific angular momentum
55- 62 E8.2 kpc.km/s jdisc Disc's specific angular momentum
64- 71 E8.2 kpc.km/s e_jstar Uncertainty on the specific angular momenta
73- 76 F4.2 --- jdiff Relative difference between last 2 points of
jstar profile (4)
78- 81 F4.2 --- jgrad Gradient of jstar profile at last
grid point (4)
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Note (1): same convention as in Lelli, McGaugh & Schombert, 2016,
Cat. J/AJ/152/157
Note (2): SPARC galaxies classification depending on the distance estimate
is defined as follows:
1 = Hubble-Flow assuming H0=73km/s/Mpc and correcting for Virgo-centric infall
2 = Magnitude of the tip of the red giant branch
3 = Cepheids magnitude-period relation
4 = Ursa Major cluster of galaxies
5 = Supernovae light curve
Note (3): the following 3.6mu mass-to-light ratios have been used
M/Lbulge=0.5, M/Ldisc=0.7.
Note (4): these two quantities define the quality of the measured specific
angular momentum profile and they are defined in Equation (2). Galaxies with
"converged" jstar(<R) profiles are those with jdifflast=jgradlast=0
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Acknowledgements:
Lorenzo Posti, posti(at)astro.rug.nl
(End) Patricia Vannier [CDS] 16-Apr-2018