2008ApJ...686.1007B


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.31CET12:33:24

2008ApJ...686.1007B - Astrophys. J., 686, 1007-1018 (2008/October-3)

AGB connection and ultraviolet luminosity excess in elliptical galaxies.

BUZZONI A. and GONZALEZ-LOPEZLIRA R.A.

Abstract (from CDS):

Relying on infrared surface brightness fluctuactions to trace AGB properties in a sample of elliptical galaxies in the Virgo and Fornax Clusters, we assess the puzzling origin of the ``UV upturn'' phenomenon, recently traced to the presence of a hot horizontal branch (HB) stellar component. The UV upturn actually signals a profound change in the galaxy stellar populations, involving both the hot stellar component and red giant evolution. In particular, the strengthening of the UV rising branch is always seen to correspond to a shortening in AGB deployment; this trend can be readily interpreted as an age effect, perhaps mildly modulated by metal abundance. Brightest stars in ellipticals are all found to be genuine AGB members, all the way, and with the AGB tip exceeding the RGB tip by some 0.5-1.5 mag. The inferred core mass of these stars is found to be ≲0.57 M among giant ellipticals. This value accounts for the recognized deficiency of planetary nebulae in these galaxies, as a result of a lengthy transition time for the post-AGB stellar core to become a hard UV emitter and eventually ``fire up'' the nebula. The combined study of galaxy (1550-V)0 color and integrated Hβ index points to a a bimodal temperature distribution for the HB with both a red clump and an extremely blue component, in a relative proportion [N(RHB):N(BHB)]~[80:20]. For the BHB stellar population, [Fe/H] values of either ≃-0.7 or ≳+0.5 dex may provide the optimum ranges to feed the needed low-mass stars (M*≪0.58 M) that at some stage begin to join the standard red clump stars.

Abstract Copyright:

Journal keyword(s): Galaxies: Elliptical and Lenticular, cD - Galaxies: Evolution - Stars: AGB and Post-AGB - Stars: Mass Loss - Ultraviolet: Galaxies

Simbad objects: 29

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Number of rows : 29

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 104 GlC 00 24 05.359 -72 04 53.20   5.78 4.09     ~ 3575 0
2 M 32 IG 00 42 41.825 +40 51 54.61 9.51 9.03 8.08     ~ 2022 2
3 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 11057 1
4 NGC 1316 GiP 03 22 41.789 -37 12 29.52 9.81 9.15 8.53 7.66   ~ 1216 1
5 NGC 1379 GiP 03 36 03.940 -35 26 28.23 12.17 12.04 10.91 10.60   ~ 243 1
6 NGC 1387 GiP 03 36 57.0325944947 -35 30 23.691986124 12.18 11.75 10.69 10.16   ~ 222 1
7 NGC 1389 GiP 03 37 11.7424496792 -35 44 45.871664087 12.80 12.39 11.50 10.99   ~ 175 1
8 NGC 1399 BiC 03 38 29.083 -35 27 02.67 11.05 9.74 9.59 8.12   ~ 1463 1
9 ACO S 373 ClG 03 38 30 -35 27.3           ~ 1568 0
10 NGC 1404 GiP 03 38 51.917 -35 35 39.81 11.53 10.69 10.00 9.03   ~ 675 1
11 NGC 2808 GlC 09 12 03.10 -64 51 48.6   7.77 5.69     ~ 1254 0
12 NGC 3115 GiG 10 05 13.978 -07 43 06.89   11   9.37   ~ 936 2
13 M 105 LIN 10 47 49.600 +12 34 53.87   10.56 9.76 9.12 8.18 ~ 1385 0
14 NAME M96 Group GrG 10 48 +13.3           ~ 281 0
15 NGC 3384 GiG 10 48 16.897 +12 37 45.48   10.0       ~ 555 1
16 NGC 4278 LIN 12 20 06.8253868 +29 16 50.713486 11.54 11.09 10.16     ~ 892 2
17 M 84 Sy2 12 25 03.74333 +12 53 13.1393 12.67 12.09 10.49     ~ 1645 2
18 M 86 GiG 12 26 11.814 +12 56 45.49 10.32 9.83 8.90   7.50 ~ 1019 1
19 NAME Vir I ClG 12 26 32.1 +12 43 24   10.00 8.49     ~ 5909 0
20 M 49 Sy2 12 29 46.798 +08 00 01.48   13.21 12.17     ~ 1971 2
21 M 87 BiC 12 30 49.42338230 +12 23 28.0438581 10.16 9.59 8.63   7.49 ~ 6283 3
22 M 89 LIN 12 35 39.8073444 +12 33 22.830809 11.29 10.73 9.75     ~ 931 2
23 M 59 GiG 12 42 02.322 +11 38 48.95   11.0       ~ 662 0
24 M 60 GiP 12 43 40.008 +11 33 09.40   10.3       ~ 1258 0
25 NGC 5139 GlC 13 26 47.28 -47 28 46.1   6.12 5.33     ~ 3032 0
26 NGC 6388 GlC 17 36 17.461 -44 44 08.34   7.40       ~ 810 1
27 NGC 6441 GlC 17 50 13.06 -37 03 05.2   9.26 8.00     ~ 772 0
28 NGC 6791 OpC 19 20 53 +37 46.3   10.52 9.5     ~ 880 0
29 NAME Local Group GrG ~ ~           ~ 7076 0

    Equat.    Gal    SGal    Ecl

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2020.10.31-12:33:24

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