2007A&A...470..173B


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.19CEST18:39:59

2007A&A...470..173B - Astronomy and Astrophysics, volume 470, 173-178 (2007/7-4)

The formation of S0 galaxies: evidence from globular clusters.

BARR J.M., BEDREGAL A.G., ARAGON-SALAMANCA A., MERRIFIELD M.R. and BAMFORD S.P.

Abstract (from CDS):

We devise a simple experiment to test the theory that lenticular (S0) galaxies form from spirals whose star formation has been shut down. An individual galaxy's fading is measured using the globular cluster specific frequency (SN), defined as the number of globular clusters normalised by the galaxy luminosity. This is compared with a spectroscopically-derived age estimate. We make NTT/EMMI long-slit spectroscopic observations of 11 S0 galaxies at z<0.006. We measure the absorption-line indices, Hδ, Hγ, Mgb, Fe5270 and Fe5335 within the central re/8. By inverting single-stellar population models, luminosity-weighted mean ages, metallicities and α-element abundance ratios are derived. We estimate the amount of fading a galaxy has undergone by comparing each galaxy's SN with its deviation from the mean spiral SN. Galaxies with higher SN have older stellar populations. Moreover, we find that the zero-point and amount of fading is consistent with a scenario where lenticulars are formed by the quenching of star formation in spiral galaxies. Our data also rule out any formation method for S0s which creates a large number of new globular clusters. We confirm that previous results showing a relationship between SN and color are driven by the SN -Age relation. Five galaxies show detectable Hβ, [OIII], Hα or [NII] emission lines. However, only in the two youngest galaxies is this emission unambiguously from star formation. Our results are consistent with the theory that S0 galaxies are formed when gas in normal spirals is removed, possibly as a result of a change in environment. The on-going star formation in the youngest galaxies hints that the timescale of quenching is ≲1Gyr. We speculate, therefore, that the truncation of star formation is a rather gentle process unlikely to involve a rapid burst of star formation.

Abstract Copyright:

Journal keyword(s): galaxies: formation - galaxies: evolution - galaxies: structure - galaxies: star clusters

Simbad objects: 15

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Number of rows : 15

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 EGGR 382 WD? 00 33 54.4629052338 -12 07 58.777597136 15.511 15.572 14.891 14.467 14.051 DC? 92 0
2 NGC 1201 GiG 03 04 07.969 -26 04 10.53   11.78 10.64 10.35   ~ 132 0
3 IC 1919 GiG 03 26 02.2131461212 -32 53 40.326286596   13.78   12.60   ~ 72 0
4 NGC 1332 GiP 03 26 17.321 -21 20 07.33   11.45   9.84   ~ 310 0
5 NGC 1389 GiP 03 37 11.7424496792 -35 44 45.871664087 12.80 12.39 11.50 10.99   ~ 175 1
6 NGC 1400 EmG 03 39 30.851 -18 41 17.25 12.48 12.01 10.96 10.45   ~ 280 1
7 GD 50 WD* 03 48 50.1861716368 -00 58 32.290158840 12.596 13.787 14.063 14.210 14.388 DA1.2 237 0
8 NGC 1553 GiP 04 16 10.4711638537 -55 46 48.107262747 10.76 10.10 9.40 8.74   ~ 356 2
9 NGC 1581 GiG 04 24 44.9218112977 -54 56 31.347626096   13.36   12.24   ~ 42 0
10 NGC 2902 GiG 09 30 52.892 -14 44 08.98   13.1   12.03 12.4 ~ 64 0
11 NGC 3056 GiG 09 54 32.8546621996 -28 17 53.618094371   12.61   11.00 12.0 ~ 69 0
12 GD 108 HS* 10 00 47.2462037648 -07 33 30.777365253 12.406 13.349 13.563 13.662 13.781 sdB 129 1
13 NAME NGC 3115 DW1 GiG 10 05 41.5916956639 -07 58 53.592496977   14.32 13.45     ~ 78 1
14 NGC 3156 GiG 10 12 41.2459118495 +03 07 45.693904357   12.8       ~ 223 0
15 Feige 110 HS* 23 19 58.3995050606 -05 09 56.170282845 10.360 11.45 11.50 11.970 12.145 sdO8VIIIHe5 559 1

    Equat.    Gal    SGal    Ecl

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2020.10.19-18:39:59

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