Star formation history of early–type galaxies in low density environments III. The isophote shape parameter and nuclear line–strength indices

نویسندگان

  • R. Rampazzo
  • M. D’Onofrio
  • P. Bonfanti
چکیده

Using two line–strength indices, H+K(CaII) and ∆4000, sensible to the age of the stellar population, we analyze the correlations between the shape and the ‘galaxy age’ suggested by de Jong & Davies (1997) on the basis that discy galaxies have higher Hβ indices. By enlarging their sample with the present one, we find that the significance of the correlation a4/a vs. line– strength indices disappears. We conclude that the ‘age of the stellar population of earlytype galaxies’ is not correlated to the isophote shape parameter.

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تاریخ انتشار 1998