The exponential scale length

**Figure:** Logarithm of the exponential scale-length in parsecs, 141#141 vs. absolute 10#10 magnitude. The group&field sample galaxies are coded with different symbols according to their environment, see the legend. Cluster galaxies are represented by small dots. The solid line is a fit to the cluster sample, the dashed line the same relation shifted to fit the group&field data within the analysis range 47#47.
140#140

The difference between the group&field and cluster samples in this case is a trend towards smaller scale length at equal absolute magnitude.

A relation 142#142 was fitted over the range 143#143 to 51#51, and the results are summarized in Table

. The fitted lines are plotted in Figs.

and

. The average differences in this case amount to 144#144 for the whole sample, 145#145 for the early type subsample and 146#146 for the late type subsample.

**Figure:** Logarithm of the exponential scale-length 141#141 versus absolute 10#10 magnitude, for early type dwarfs. The symbols are as in Fig. . The solid line is a fit to the cluster sample, the dashed line the same relation shifted to fit the group&field data within the analysis range 47#47. The dash-dotted line is a fit to the group&field data in the range 148#148.Early types are plotted in the left plot and late types in the right.
147#147

The distributions of scale-length, binned in one magnitude bins from 50#50 to 51#51, are shown in Fig.

. The results of the KS test as described in the previous sections, as well as the mean values and standard deviations in each bin are summarized in Table

**Table:** Coefficients of robust fits to the data shown in Figs. and , i.e. exponential scale length 139#139 vs. absolute magnitude. The fits are of the form 142#142.
Sample	54#54	149#149	150#150	59#59	60#60
C All	151#151	152#152	153#153	154#154	-
C Early	151#151	155#155	153#153	154#154	-
C Late	156#156	157#157	68#68	158#158	-
G/F All	-	159#159	72#72	160#160	72#72
G/F Early	-	161#161	162#162	163#163	83#83
G/F Early	-	164#164	72#72	86#86	165#165
G/F Late	-	166#166	167#167	160#160	168#168

From Table

one can see that the exponential scale-lengths of the early types and late types in the cluster sample are roughly the same, whereas in the group&field sample they differ significantly. The late types in the the group&field are larger than the early types in the same environment, for a fixed absolute magnitude. The group&field galaxies are systematically smaller than the cluster galaxies of same absolute magnitude.

**Figure:** Distributions of 141#141 for all galaxies (a), early types only (b) and late types only (c), binned in absolute magnitude. The bins are indicated in the plots. Hatched histograms represent the group&field sample. Open histograms represent the cluster sample.
169#169

**Table:** Mean values of 141#141 for the cluster and group&field samples, in one magnitude bins, as well as results of a KS test applied to the distributions in the respective bins. The results for the whole sample are in the top part, the early types in the middle and late types in the bottom part. The KS probabilities for which a larger magnitude bin width was used are indicated.
Bin	cluster	field	ks prob
92#92	170#170	171#171	172#172
96#96	173#173	174#174	175#175
100#100	176#176	177#177	178#178
104#104	179#179	180#180	181#181
108#108	182#182	183#183	-
92#92	184#184	185#185	186#186
96#96	187#187	188#188	189#189
100#100	190#190	191#191	192#192
104#104	193#193	194#194	195#195
108#108	196#196	-	-
92#92	197#197	198#198	199#199
96#96	200#200	201#201	202#202
100#100	203#203	204#204	205#205
104#104	206#206	207#207	208#208
108#108	209#209	183#183	-

Proceeding as in the previous cases, the parameters of linear fits to the mean values given in Table

give 210#210 and 211#211 for the field and cluster samples respectively. From these, one sees that the faint field galaxies tend to be smaller at given absolute magnitude than their cluster counterparts, whereas the difference is smaller for the brighter galaxies. In the case of the early type galaxies, one has 212#212 and 213#213, i.e. an opposite trend, the difference between the field and cluster early types being larger, in the sense field galaxies being bigger, for the brighter galaxies than for the faint galaxies.