2013AJ....146..144A


C.D.S. - SIMBAD4 rel 1.7 - 2020.02.27CET22:27:10

2013AJ....146..144A - Astron. J., 146, 144 (2013/December-0)

The star formation history of the very metal-poor blue compact dwarf I zw 18 from HST/ACS data.

ANNIBALI F., CIGNONI M., TOSI M., VAN DER MAREL R.P., ALOISI A., CLEMENTINI G., CONTRERAS RAMOS R., FIORENTINO G., MARCONI M. and MUSELLA I.

Abstract (from CDS):

We have derived the star formation history (SFH) of the blue compact dwarf galaxy I Zw 18 through comparison of deep HST/ACS data with synthetic color-magnitude diagrams (CMDs). A statistical analysis was implemented for the identification of the best-fit SFH and relative uncertainties. We confirm that I Zw 18 is not a truly young galaxy, having started forming stars earlier than ∼1 Gyr ago, and possibly at epochs as old as a Hubble time. In I Zw 18's main body we infer a lower limit of ~2x106 M for the mass locked up in old stars. I Zw 18's main body has been forming stars very actively during the last ∼10 Myr, with an average star formation rate (SFR) as high as ~1 M/yr (or ~2x10–5 M/yr/pc2). On the other hand, the secondary body was much less active at these epochs, in agreement with the absence of significant nebular emission. The high current SFR can explain the very blue colors and the high ionized gas content in I Zw 18, resembling primeval galaxies in the early universe. Detailed chemical evolution models are required to quantitatively check whether the SFH from the synthetic CMDs can explain the low measured element abundances, or if galactic winds with loss of metals are needed.

Abstract Copyright:

Journal keyword(s): galaxies: dwarf - galaxies: individual: I Zw18 - galaxies: irregular - galaxies: starburst

Simbad objects: 7

goto Full paper

goto View the reference in ADS

Number of rows : 7

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 NAME Mayall II GlC 00 32 46.53 +39 34 40.5   14.564 13.807 13.208 12.684 ~ 367 1
2 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 10714 1
3 NGC 1569 IG 04 30 49.186 +64 50 52.52 11.72 11.86 11.03     ~ 1143 3
4 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14557 1
5 NAME 30 Dor Nebula SFR 05 38 36.0 -69 05 11           ~ 1030 2
6 Mrk 116 PaG 09 34 02.1 +55 14 25           ~ 986 1
7 NGC 5139 GlC 13 26 47.28 -47 28 46.1   6.12 5.33     ~ 2954 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2013AJ....146..144A and select 'bookmark this link' or equivalent in the popup menu


2020.02.27-22:27:10

© Université de Strasbourg/CNRS

    • Contact