2016ApJ...829...45K


C.D.S. - SIMBAD4 rel 1.7 - 2021.05.17CEST03:35:00

2016ApJ...829...45K - Astrophys. J., 829, 45-45 (2016/September-3)

Equilibrium sequences and gravitational instability of rotating isothermal rings.

KIM W.-T. and MOON S.

Abstract (from CDS):

Nuclear rings at the centers of barred galaxies exhibit strong star formation activities. They are thought to undergo gravitational instability when they are sufficiently massive. We approximate them as rigidly rotating isothermal objects and investigate their gravitational instability. Using a self-consistent field method, we first construct their equilibrium sequences specified by two parameters: α corresponding to the thermal energy relative to gravitational potential energy, and R_{B} measuring the ellipticity or ring thickness. Unlike in the incompressible case, not all values of R_{B} yield an isothermal equilibrium, and the range of R_{B} for such equilibria shrinks with decreasing α. The density distributions in the meridional plane are steeper for smaller α, and well approximated by those of infinite cylinders for slender rings. We also calculate the dispersion relations of non-axisymmetric modes in rigidly rotating slender rings with angular frequency Ω_0 and central density ρ_c. Rings with smaller α are found more unstable with a larger unstable range of the azimuthal mode number. The instability is completely suppressed by rotation when Ω_0 exceeds the critical value. The critical angular frequency is found to be almost constant at ∼0.7{(Gρ_c)}^{1/2} for α >= 0.01 and increases rapidly for smaller α. We apply our results to a sample of observed star-forming rings and confirm that rings without a noticeable azimuthal age gradient of young star clusters are indeed gravitationally unstable.

Abstract Copyright: © 2016. The American Astronomical Society. All rights reserved.

Journal keyword(s): galaxies: ISM - galaxies: kinematics and dynamics - galaxies: nuclei - galaxies: structure - instabilities - stars: formation - stars: formation

CDS comments: In Table 3: NGC IC14 is a probable misprint for IC1438.

Simbad objects: 20

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Number of rows : 20

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NGC 473 LSB 01 19 55.0591751679 +16 32 41.288307933   13.41 12.63     ~ 79 0
2 NGC 613 AGN 01 34 18.235 -29 25 06.56   10.77 12.71 9.50 10.6 ~ 363 3
3 NGC 1097 LIN 02 46 19.059 -30 16 29.68 10.46 9.97 9.48 8.72 9.8 ~ 1211 3
4 NGC 1300 GiP 03 19 41.0453355271 -19 24 40.141850719   11.16 10.42 9.90 10.7 ~ 460 0
5 NGC 1343 G 03 37 49.7251634461 +72 34 16.607101942   14.1       ~ 67 0
6 NGC 1530 G 04 23 27.102 +75 17 44.05   13.40       ~ 261 1
7 NGC 2905 H2G 09 32 10.111 +21 30 02.99 10.44 9.75 9.07 8.68   ~ 1019 3
8 M 95 GiP 10 43 57.69173 +11 42 13.6274 10.71 10.51 9.73 9.48   M0 978 2
9 M 61 Sy2 12 21 54.9275149050 +04 28 25.588335799 10.07 10.18 9.65     ~ 903 2
10 NGC 4314 LIN 12 22 31.978 +29 53 43.09 11.72 11.43 10.58     ~ 458 1
11 M 100 AGN 12 22 54.9318850854 +15 49 20.294302163 10.04 10.05 9.35     ~ 1692 2
12 NGC 5248 GiG 13 37 32.069 +08 53 06.22   11.4       ~ 462 0
13 NGC 5728 Sy2 14 42 23.928 -17 15 11.41   14.34 13.40     ~ 524 0
14 NGC 5905 H2G 15 15 23.324 +55 31 01.59   13.6       ~ 254 1
15 NGC 5953 GiP 15 34 32.402 +15 11 37.80   13.23 12.45     ~ 345 1
16 NGC 6951 Sy2 20 37 14.1181441937 +66 06 20.078027288   11.64 10.65     ~ 504 2
17 IC 1438 EmG 22 16 29.106 -21 25 50.62   12.63   11.57   ~ 75 0
18 NGC 7552 GiP 23 16 10.767 -42 35 05.39 11.34 11.22 10.57 10.08 11.1 ~ 515 3
19 NGC 7716 G 23 36 31.458 +00 17 50.33   12.9   13.0 12.6 ~ 147 0
20 NGC 7752 GiP 23 46 58.557 +29 27 32.17   14.3       ~ 122 0

    Equat.    Gal    SGal    Ecl

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2021.05.17-03:35:00

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