2000ApJ...538..569R


C.D.S. - SIMBAD4 rel 1.7 - 2020.04.06CEST11:49:39

2000ApJ...538..569R - Astrophys. J., 538, 569-580 (2000/August-1)

Lopsided galaxies, weak interactions, and boosting the star formation rate.

RUDNICK G., RIX H.-W. and KENNICUTT R.C.Jr

Abstract (from CDS):

To investigate the link between weak tidal interactions in disk galaxies and the boosting of their recent star formation, we obtain images and spatially integrated spectra (3615 Å≤λ≤5315 Å) for 40 late-type spiral galaxies (Sab-Sbc) with varying degrees of lopsidedness (a dynamical indicator of weak interactions). We quantify lopsidedness as the amplitude <A{d5}1> of the m=1 Fourier component of the azimuthal surface brightness distribution averaged over a range of radii. The median spectrum of the most lopsided galaxies shows strong evidence for a more prominent young stellar population (i.e., strong Balmer absorption, strong nebular emission, a weak 4000 Å break, and a blue continuum) when compared to the median spectrum of the most symmetric galaxies. We compare the young stellar content, quantified by EW(Hδabs) and the strength of the 4000 Å break (D4000), with lopsidedness and find a 3-4 σ correlation between the two. We also find a 3.2 σ correlation between EW(Hβemission) and lopsidedness. Using the evolutionary population synthesis code of Bruzual & Charlot we model the spectra as an ``underlying population'' and a superimposed ``boost population'' with the aim of constraining the fractional boost in the SFR averaged over the past 0.5 Gyr (the characteristic lifetime of lopsidedness). From the difference in both EW(Hδabs) and the strength of the 4000 Å break (D4000) between the most and least symmetric thirds of our sample, we infer that ∼1x109 M of stars are formed over the duration of a lopsided event in addition to the ``underlying'' star formation history (assuming a final galactic stellar mass of 1010 M). This corresponds to a factor of 8 increase in the star formation rate over the past 5x108 years. For the nuclear spectra, all of the above correlations except D4000 versus <A{d5}1> are weaker than for the disk, indicating that in lopsided galaxies, the star formation boost is not dominated by the nucleus.

Abstract Copyright:

Journal keyword(s): Galaxies: Evolution - Galaxies: Interactions - Galaxies: Kinematics and Dynamics - Galaxies: Spiral - Galaxies: Structure - Stars: Formation

Status at CDS:  

Simbad objects: 40

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Number of rows : 40

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 2347 LIN 07 16 04.087 +64 42 41.54   13.2       ~ 101 0
2 NGC 2582 LIN 08 25 12.0710981111 +20 20 05.057032900   14.3       ~ 56 0
3 IC 520 GiG 08 53 42.2492333067 +73 29 27.433036188   11.9       ~ 45 0
4 NGC 2744 GiG 09 04 39.020 +18 27 52.14   13.7       ~ 47 0
5 NGC 2916 Sy2 09 34 57.5939750994 +21 42 18.947459809 12.81 12.74 12.05     ~ 123 1
6 NGC 3066 GiP 10 02 10.9014314395 +72 07 30.850746153   12.8       ~ 71 0
7 NGC 3162 GiG 10 13 31.5928405755 +22 44 15.161785167   12.2       ~ 121 0
8 NGC 3177 AGN 10 16 34.1437574295 +21 07 22.986941605   12.8       ~ 130 0
9 NGC 3310 AGN 10 38 45.857 +53 30 11.89   12.45 12.15     ~ 724 1
10 NGC 3353 AGN 10 45 22.390 +55 57 37.36 12.90 13.25 12.79     ~ 316 1
11 NGC 3681 GiG 11 26 29.7823852250 +16 51 48.268851452   12.2       ~ 129 0
12 NGC 3684 GiP 11 27 11.173 +17 01 49.12   12.1       ~ 153 0
13 NGC 3897 LIN 11 48 59.4581517223 +35 00 57.693778245   14.2       ~ 38 0
14 NGC 3928 AGN 11 51 47.6189114011 +48 40 59.276693861   13.1       ~ 156 0
15 NGC 3963 GiP 11 54 58.7341909664 +58 29 37.013974281   12.2       ~ 110 0
16 NGC 4017 rG 11 58 45.626 +27 27 08.41   13.5       ~ 87 0
17 NGC 4041 SyG 12 02 12.2373728821 +62 08 14.095878409   11.6       ~ 224 1
18 UGC 7416 AGN 12 21 39.199 +40 50 55.64   13.863 13.190 12.673 12.059 ~ 63 0
19 NGC 4351 GiG 12 24 01.560 +12 12 18.09   13.5       ~ 190 0
20 NGC 4412 Sy2 12 26 36.0838908611 +03 57 52.923602148   13.2       ~ 124 0
21 NGC 4430 GiP 12 27 26.4014958744 +06 15 45.975179068   13.4       ~ 139 0
22 NGC 4595 GiG 12 39 51.9129989652 +15 17 51.960292929   12.8       ~ 179 0
23 NGC 4639 GiP 12 42 52.3781396179 +13 15 26.712929286   13.62 12.72     ~ 551 0
24 NGC 4814 GiP 12 55 21.9163972177 +58 20 38.628435405   12.4       ~ 87 0
25 NGC 4911 LIN 13 00 56.0616026595 +27 47 27.151217355 14.58 13.7 13.33 12.601 12.068 ~ 179 0
26 NGC 5218 GiP 13 32 10.4287653669 +62 46 04.126116981   13.1       ~ 140 1
27 IC 900 GiG 13 34 43.0155124244 +09 20 12.797702932   14.3       ~ 53 0
28 NGC 5614 IG 14 24 07.591 +34 51 32.02   12.6       ~ 118 0
29 NGC 5653 H2G 14 30 10.411 +31 12 55.86   12.7       ~ 154 0
30 NGC 5713 GiP 14 40 11.528 -00 17 21.16 11.88 11.84 11.20     ~ 344 2
31 NGC 5923 LIN 15 21 14.256 +41 43 33.41   14.7       ~ 31 0
32 NGC 5915 GiP 15 21 33.076 -13 05 30.22   13.1   12.32 12.7 ~ 100 0
33 NGC 5936 H2G 15 30 00.846 +12 59 21.55   13.0       ~ 149 1
34 NGC 6012 G 15 54 13.9058160507 +14 36 04.281115506   13.209 12.420 11.870 11.195 ~ 115 0
35 NGC 6195 LIN 16 36 32.5655877037 +39 01 40.409449250   14.7       ~ 70 0
36 IC 1269 G 17 52 05.859 +21 34 09.03   14.026 13.218 12.709 12.189 ~ 43 0
37 NGC 6574 GiG 18 11 51.2462161679 +14 58 54.740459628   12.5       ~ 169 0
38 NGC 6711 G 18 49 00.902 +47 39 29.09   13.984 13.267 12.735 12.222 ~ 42 0
39 NGC 6824 GiG 19 43 40.671 +56 06 34.00   13.1       ~ 60 0
40 NGC 7177 LIN 22 00 41.250 +17 44 17.22   12.2       ~ 184 0

    Equat.    Gal    SGal    Ecl

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2020.04.06-11:49:39

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