J/A+A/623/A123 Einasto parameters for SPARC galaxies (Ghari+, 2019)
Dark matter-baryon scaling relations from Einasto halo fits to SPARC galaxy
rotation curves.
Ghari A., Famaey B., Laporte C., Haghi H.
<Astron. Astrophys. 623, A123 (2019)>
=2019A&A...623A.123G 2019A&A...623A.123G (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, rotation
Keywords: galaxies: kinematics and dynamics - galaxies: spiral - dark matter
Abstract:
Dark matter-baryon scaling relations in galaxies are important in
order to constrain galaxy formation models. Here, we provide a modern
quantitative assessment of those relations, by modelling the rotation
curves of galaxies from the Spitzer Photometry and Accurate Rotation
Curves (SPARC) database with the Einasto dark halo model. We focus in
particular on the comparison between the original SPARC parameters,
with constant mass-to-light ratios for bulges and disks, and the
parameters for which galaxies follow the tightest radial acceleration
relation. We show that fits are improved in the second case, and that
the pure halo scaling relations also become tighter. We report that
the density at the radius where the slope is -2 is strongly
anticorrelated to this radius, and to the Einasto index. The latter is
close to unity for a large number of galaxies, indicative of large
cores. In terms of dark matter-baryon scalings, we focus on relations
between the core properties and the extent of the baryonic component,
which are relevant to the cusp-core transformation process. We report
a positive correlation between the core size of halos with small
Einasto index and the stellar disk scale-length, as well as between
the averaged dark matter density within 2kpc and the baryon-induced
rotational velocity at that radius. This finding is related to the
consequence of the radial acceleration relation on the diversity of
rotation curve shapes, quantified by the rotational velocity at 2kpc.
While a tight radial acceleration relation slightly decreases the
observed diversity compared to the original SPARC parameters, the
diversity of baryon-induced accelerations at 2kpc is sufficient to
induce a large diversity, incompatible with current hydrodynamical
simulations of galaxy formation, while maintaining a tight radial
acceleration relation.
Description:
Maximum posterior dark matter halo parameters of individual rotation
curve fits to 160 SPARC galaxies with Q<3 and parameters from Li et
al. (2018A&A...615A...3L 2018A&A...615A...3L).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 92 160 Rotation curve fit results
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See also:
J/AJ/152/157 : Mass models for 175 disk galaxies with SPARC (Lelli+, 2016)
http://astroweb.cwru.edu/SPARC/ : SPARC database
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Name Name of the galaxies
15- 21 F7.3 10-3Msun/pc+3 rho-2 Einasto parameter rho-2,
density at radius r-2
23- 28 F6.3 10-3Msun/pc+3 e_rho-2 Error on rho-2 (lower value,
68 percent confidence interval)
30- 35 F6.3 10-3Msun/pc+3 E_rho-2 Error on rho-2 (upper value,
68 percent confidence interval)
37- 43 F7.3 kpc r-2 Einasto parameter r-2, radius at which
the density profile has a slope of -2
45- 50 F6.3 kpc e_r-2 Error on r-2 (lower value,
68 percent confidence interval)
52- 57 F6.3 kpc E_r-2 Error on r-2 (upper value,
68 percent confidence interval)
59- 64 F6.3 --- n Einasto index n, sets the general
shape of the density profile
66- 70 F5.3 --- e_n Error on n (lower value,
68 percent confidence interval)
72- 76 F5.3 --- E_n Error on n (upper value,
68 percent confidence interval)
78- 84 F7.3 km/s Vmax Maximum circular velocity of the halo
86- 92 F7.3 km/s Vrot Rotational velocity at 2kpc from
the center
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Acknowledgements:
Amir Ghari, amir.ghari(at)iasbs.ac.ir
(End) Patricia Vannier [CDS] 31-Jan-2019