J/MNRAS/495/58 Dwarf galaxy rotational velocities (Santos-Santos+, 2020)
Baryonic clues to the puzzling diversity of dwarf galaxy rotation curves.
Santos-Santos I.M.E., Navarro J.F., Robertson A., Benitez-Llambay A.,
Oman K.A., Lovell M.R., Frenk C.S., Ludlow A.D., Fattahi A., Ritz A.
<Mon. Not. R. Astron. Soc., 495, 58-77 (2020)>
=2020MNRAS.495...58S 2020MNRAS.495...58S (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, dwarf ; Galaxies, rotation ; Galaxies, radius ;
Rotational velocities ; Optical ; Infrared
Keywords: galaxies: dwarf - galaxies: evolution - galaxies: formation -
galaxies: haloes - dark matter - cosmology: theory
Abstract:
We use a compilation of disc galaxy rotation curves to assess the role
of the luminous component ('baryons') in the rotation curve diversity
problem. As in earlier work, we find that rotation curve shape
correlates with baryonic surface density: high surface density
galaxies have rapidly rising rotation curves consistent with cuspy
cold dark matter haloes; slowly rising rotation curves (characteristic
of galaxies with inner mass deficits or 'cores') occur only in low
surface density galaxies. The correlation, however, seems too weak to
be the main driver of the diversity. In addition, dwarf galaxies
exhibit a clear trend, from 'cuspy' systems where baryons are
unimportant in the inner mass budget to 'cored' galaxies where baryons
actually dominate. This trend constrains the various scenarios
proposed to explain the diversity, such as (i) baryonic inflows and
outflows during galaxy formation; (ii) dark matter self-interactions;
(iii) variations in the baryonic mass structure coupled to rotation
velocities through the 'mass discrepancy-acceleration relation'
(MDAR); or (iv) non-circular motions in gaseous discs. Together with
analytical modelling and cosmological hydrodynamical simulations, our
analysis shows that each of these scenarios has promising features,
but none seems to fully account for the observed diversity. The MDAR,
in particular, is inconsistent with the observed trend between
rotation curve shape and baryonic importance; either the trend is
caused by systematic errors in the data or the MDAR does not apply.
The origin of the dwarf galaxy rotation curve diversity and its
relation to the structure of cold dark matter haloes remains an open
issue.
Description:
Our compilation of rotation curves from the literature includes data
sets from the Spitzer Photometry & Accurate Rotation Curves project
(SPARC; Lelli et al. 2016AJ....152..157L 2016AJ....152..157L, Cat. J/AJ/152/157); from The
HI Nearby Galaxy Survey (THINGS; de Blok et al. 2008AJ....136.2648D 2008AJ....136.2648D);
from the Local Irregulars That Trace Luminosity Extremes, The HI
Nearby Galaxy Survey (LITTLE THINGS ; Oh et al. 2015AJ....149..180O 2015AJ....149..180O);
as well as from the work of Adams et al. (2014ApJ...789...63A 2014ApJ...789...63A) and
Relatores et al. (2019ApJ...873....5R 2019ApJ...873....5R).
All rotation curves in this compilation were inferred from
high-resolution HI and/or Hα velocity fields, and include
asymmetric drift corrections when needed. In all cases the velocity
field data has been combined with photometry to construct mass models
that include the stellar, gaseous, and dark matter components. In
particular, the SPARC, THINGS, and LITTLE THINGS data make use of
Spitzer 3.6µm surface photometry, while Adams et al.
(2014ApJ...789...63A 2014ApJ...789...63A) and Relatores et al. (2019ApJ...873....5R 2019ApJ...873....5R) use
r-band images from a variety of sources. If the same galaxy is common
to more than one survey, we adopt the SPARC data, because the majority
of galaxies in our sample come from that compilation.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 66 160 Observational data used in this work
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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: tablea1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Galaxy name
13- 14 A2 --- Sample Sample the galaxy belongs to (1)
16- 21 F6.2 km/s Vmax Maximum circular velocity
23- 28 F6.2 km/s Vbmax Baryonic contribution to Vmax
30- 35 F6.2 km/s Vfid Rotation velocity at the fiducial inner
radius (rfid) (2)
37- 42 F6.2 km/s Vbfid Baryonic contribution to Vfid
44- 51 E8.3 Msun Mbar Total baryonic mass
53- 57 F5.2 kpc rbhalf Half mass radius of the galaxy
59- 66 E8.3 Msun M200 Virial mass
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Note (1): Sample as follows:
S = SPARC, Lelli et al. (2016AJ....152..157L 2016AJ....152..157L, Cat. J/AJ/152/157)
LT = LITTLE THINGS, Oh et al. (2015AJ....149..180O 2015AJ....149..180O)
TH = THINGS, de Blok et al. (2008AJ....136.2648D 2008AJ....136.2648D)
A = Adams et al. (2014ApJ...789...63A 2014ApJ...789...63A)
R = Relatores et al. (2019ApJ...873....5R 2019ApJ...873....5R)
Note (2): The fiducial inner radius is defined as rfid=2(Vmax/70) (in kpc)
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 06-Jun-2023