J/ApJ/517/650 Surface photometry of dwarf galaxies in Virgo (Ryden+, 1999)
Detailed surface photometry of dwarf elliptical and dwarf S0 galaxies
in the Virgo cluster
Ryden B.S., Terndrup D.M., Pogge R.W., Lauer T.R.
<Astrophys. J. 517, 650 (1999)>
=1999ApJ...517..650R 1999ApJ...517..650R
ADC_Keywords: Clusters, galaxy ; Photometry, surface
Keywords: galaxies: clusters: individual (Virgo) - galaxies:
elliptical and lenticular, cDgalaxies: photometry - galaxies:
structure
Abstract:
We analyze new V-band images of 14 dwarf S0 galaxies and 10 dwarf
elliptical galaxies in the Virgo Cluster, in combination with R-band
images of 70 dwarf elliptical galaxies from an earlier paper. We
compute the intensity-weighted mean ellipticity, the mean deviations
from elliptical isophotes, and a newly defined parameter to measure
isophotal twists. We also fit each major-axis profile to a power law
Σ(a) ∝ exp[-(a/as)n], where n is allowed to vary.
Consistent with other studies of the Virgo dwarf ellipticals, we find
that the profile shapes for the entire sample is strongly peaked near
n=1 (exponential profiles) and that no galaxies have n=1/4 (de
Vaucouleurs profile). The faintest galaxies all have nearly
exponential profiles, while the brighter ones on average have n<1. The
correlation between ellipticity and the boxy/disky parameter is
similar to that of large elliptical galaxies, suggesting that dwarfs
may also be divided into two groups with differing internal dynamics.
The Virgo dEs also show a greater degree of isophotal twisting than
more luminous elliptical galaxies.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 103 93 Results of the dwarf galaxy surface photometry
--------------------------------------------------------------------------------
See also:
J/A+AS/139/491 : BVI photometry of nearby galaxies (Makarova+, 1999)
J/MNRAS/279/595 : Blue compact dwarf galaxies in Virgo (Drinkwater+ 1996)
J/A+AS/127/367 : Virgo Photometry Catalogue (VPC) (Young+ 1998)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- VCC Galaxy number from VCC (1)
9- 12 A4 --- Class Galaxy classification from VCC (1)
14 A1 --- f_Class [N] Indicates the presence of a nucleus
17- 20 I4 yr Obs.Y Year observation was obtained in
23- 26 F4.1 arcsec Rad ? Outer fiducial radius where the intensity
is < 180 counts
33- 36 F4.2 --- Ellip Mean ellipticity
39 A1 --- f_Ellip [a] Indicates Ellip estimated in Ryden+
(1994ApJ...425...43R 1994ApJ...425...43R)
45- 48 F4.2 --- E(Rad) ? Ellipticity at Rad
53- 61 E9.2 --- Box ? Intensity weighted boxiness coefficient
66- 74 E9.2 --- e_Box ? Uncertainty in Box
77- 85 E9.2 --- Twist ? Dimensionless twisting statistic
91- 94 F4.2 --- Index ? Power law exponent of the surface
brightness (2)
100-103 F4.2 --- e_Index ? Uncertainty in Index
--------------------------------------------------------------------------------
Note (1):
VCC = Virgo Cluster Catalog. Binggeli, B., Sandage, A., & Tammann,
G. A. 1985, AJ, 90, 1681 (1985AJ.....90.1681B 1985AJ.....90.1681B)
Note (2): surface brightness ∝ exp[-(semi-major axis/scale radius)n].
An Index value of 1 and 1/4 are exponential and de Vaucouleurs (1948)
profiles respectively.
--------------------------------------------------------------------------------
History:
From ApJ electronic edition
References:
de Vaucouleurs, G. 1948, Ann. d'Astrophys., 11, 247
(End) Greg Schwarz [AAS] 08-Mar-2000