Contents

A&A 408, 905-913 (2003)
DOI: 10.1051/0004-6361:20031016

Nature and environment of Very Luminous Galaxies[*]

A. Cappi1 - C. Benoist2 - L. N. da Costa3 - S. Maurogordato4


1 - INAF, Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
2 - CERGA, Observatoire de la Côte d'Azur, BP 4229, Le Mont-Gros, 06304 Nice Cedex 4, France
3 - European Southern Observatory, Karl Schwartzschildsrtra$\beta$e 2, 85748 Garching bei München, Germany
4 - CERGA, CNRS, Observatoire de la Côte d'Azur, BP 4229, Le Mont-Gros, 06304 Nice Cedex 4, France

Received 21 February 2003 / Accepted 12 June 2003

Abstract
The most luminous galaxies in the blue passband have a larger correlation amplitude than L* galaxies. They do not appear to be preferentially located in rich clusters or groups, but a significant fraction of them seem to be in systems which include fainter members. We present an analysis of fields centered on 18 Very Luminous Galaxies ( $M_B \le -21$) selected from the Southern Sky Redshift Survey 2, based on new observations and public data of the 2dF Galaxy Redshift Survey; we present also additional data on a CfA VLG and on Arp 127. We find that all the selected VLGs are physically associated with fainter companions. Moreover, there is a relation between the VLG morphology (early or late) and the dynamical properties of the system, which reflects the morphology-density relation. 6 out of the 18 SSRS2 VLGs are early type galaxies: 2 are in the center of rich Abell clusters with velocity dispersion $\sigma \sim 600$ km s-1, and the other 4 are in poor clusters or groups with $\sigma \sim 300$. The VLG extracted from the CfA catalog is also an elliptical in a Zwicky cluster. The remaining 2/3 of the sample are late-type VLGs, generally found in poorer systems with a larger spread in velocity dispersion, from $\sim$100 up to $\sim$750 km s-1. The low velocity dispersion, late-type VLG dominated systems appear to be analogous to our own Local Group. The possibile association of VLG systems with dark matter halos with mass comparable to rich groups or clusters, as suggested by the comparable correlation amplitude, would imply significant differences in the galaxy formation process. This work also shows that observing fields around VLGs represents an effective way of identifying galaxy systems which are not selected through other traditional techniques.

Key words: cosmology: observations - galaxies: distances and redshifts - galaxies: kinematics and dynamics

1 Introduction

From the analysis of the Southern Sky Redshift Survey 2 (SSRS2, da Costa et al. 1994), we have found that the amplitude of galaxy clustering increases significantly as a function of galaxy luminosity, but only when L > L* (Benoist et al. 1996; see also Willmer et al. 1998); moreover, the analysis of high-order moments shows that the bias is not linear, without a significant dependence on scale (Benoist et al. 1999), analogous to the bias between clusters and galaxies (Cappi & Maurogordato 1995). We have also found that the clustering amplitude of the most luminous galaxies in the sample, having absolute magnitude $M_B \le -21$ (i.e. $L \geq 4 L^*$), which we defined as Very Luminous Galaxies (VLGs), is similar to that of clusters, with a correlation length $r_0 \sim 16$ h-1 Mpc. From the analysis of the 2dF Galaxy Redshift Survey (2dFGRS) Norberg et al. (2001) have confirmed the reality of luminosity segregation for galaxies more luminous than L*, even if their most luminous galaxies show a correlation amplitude not as high as the SSRS2 VLGs.

The large value of the VLG correlation function could be explained if VLGs were in clusters, as originally suggested by Hamilton (1984): in this case, most of them should be luminous ellipticals. However, in our statistical analysis of the SSRS2 VLGs (Cappi et al. 1998, Paper I) we have shown that the fractions of the different morphological types are comparable to lower luminosity samples, and that most of the VLGs are not in rich clusters. Only a minority of VLGs were found in known groups, but in most cases our visual inspection of the Digitized Sky Survey images revealed the presence of fainter companions, often with signs of interaction.

In fact, if VLGs are neither in clusters nor in rich groups, they can nevertheless be associated with poorer systems. In biased galaxy formation (Kaiser 1984; Bardeen et al. 1986) more massive halos, which represent rare fluctuations of the matter density field, have a larger correlation amplitude. This suggests an association of VLGs to high density peaks; the fact that they are dominant galaxies in poor systems with much fainter galaxies can have interesting implications, concerning for example the efficiency of galaxy formation or the overabundance of predicted subhalos relative to the observed dwarf satellites of the Milky Way and M 31 (see e.g. Moore et al. 1999): for this reason, it would be useful to have a statistical sample of galaxy systems similar to our own Local Group.

Unfortunately the properties of poor galaxy systems, especially those comparable to the Local Group, are not well known. Zabludoff & Mulchaey (2000) have studied a sample of six nearby poor groups, finding evidence for a different luminosity function, with an increasing dwarf to giant galaxy ratio with the mass density of the system. More generally, Zabludoff & Mulchaey (1998, 2000) have examined the properties of 12 poor groups of galaxies with PSPC images: 9 of them have diffuse X-ray emission and a bright, central elliptical galaxy.

Our approach is complementary, as it selects another class of poor systems. In fact, a main problem is the bias on the properties of the selected galaxy groups due to the adopted selection criteria. A selection algorithm defines a priori the properties of the systems: well known examples are Abell clusters (Abell 1958) and Hickson compact groups (Hickson 1982). The introduction of automated methods can give a more objective selection, but it is obviously impossible to recover a system if only its most luminous member is present in the original photometric catalogue. Moreover, the typical friends-of-friends algorithms used to select "galaxy groups" require the detection of at least three neighbouring galaxies above the limiting magnitude of the catalogue (see e.g. White et al. 1999): this means that many groups are classified as "binaries''. It is clear that the problem becomes critical when going towards poorer and more distant systems, with increasing contamination and spurious detections.

Let us take the best example of VLG system, i.e. our Local Group, which contains two VLGs: M 31 and our Milky Way (with respectively MV=-21.2 and MV=-20.9, see van den Bergh 1999 and references therein), and is usually considered as a "typical group''. If this is true, it is surely not reflected in group catalogs, for a simple reason: VLGs are rare galaxies. For example, the third brightest galaxy of the Local Group M 33 (with an absolute magnitude MV=-18.9) would become fainter than mV=15.5 (i.e. fainter than the limit of the SSRS2) already at $z \sim 0.025$. Therefore we do not know if the properties of our Local Group are really "typical'', and only looking deeper at VLG fields we can expect to find other groups similar to our own.

In order to construct a statistical sample including, among others, also systems comparable to our Local Group, we have decided to investigate the environment of the VLGs listed in our catalogue defined in Paper I, which represent a volume-limited sample. The first step is to measure redshifts of fainter galaxies in the field of VLGs and determine the membership and velocity dispersion of the systems: in this paper we discuss data concerning the fields of 19 VLGs. In Sect. 2 we define our sample, with the VLG fields we observed at the Observatoire de Haute Provence and the selection of galaxies around VLGs extracted from the 2dFGRS; Sect. 3 presents the individual properties of the systems, while in Sect. 4 we discuss the relation between the VLGs and their environment. Our conclusions are in Sect. 5. In Appendix A we also discuss Arp 127, a pair identified in our preliminary selection as possibly including a VLG, and in Appendix B we give positions, magnitudes and redshifts of 2dFGRS galaxies in our VLG systems.

2 Definition of the sample


  \begin{figure}
\par\mbox{\epsfxsize=5.1cm \epsfbox{hisVLG014.eps}\hskip 0.1cm
...
...ace*{5.2cm}\epsfxsize=5.1cm \epsfbox{hisVLG109.eps}\hspace*{5.2cm}}
\end{figure} Figure 3: Redshift histograms of the VLG systems with $\ge $10 redshifts (dashed line: VLG redshift).

Three VLGs were selected from our catalogue of VLGs (see Table 1 in Paper I), while a fourth galaxy satisfying the VLG definition was selected from the CfA catalogue (see Geller & Huchra 1989); the 4 VLG fields were observed at OHP. Other 15 VLG fields were extracted from the 2dFGRS public catalogue, which has an overlap with the SSRS2. While partially imposed by observational constraints (see below), our selection is random with respect to the VLG properties, and should be representative of the whole sample. In fact, one third of the selected VLGs are early-type galaxies, a fraction consistent with that of the total sample published in Paper I.

2.1 Systems observed at OHP

At the Observatoire de Haute-Provence we could observe only galaxies at $\delta > -10^\circ$, while SSRS2 galaxies are south of $\delta = -2.5^\circ$. Among the 12 VLGs in our catalogue which satisfied this declination constraint, we chose three VLGs around which an inspection of DSS images had revealed the presence of galaxies fainter than the VLG but still bright enough to get a useful spectrum at the 1.93 m telescope. The selected VLGs are VLG 061, VLG 068 and VLG 074. In order to cover the whole night, we included also a VLG galaxy selected from the CfA catalogue (VLG 0716+5323), and Arp 127, a galaxy we had included in a preliminary version of the VLG catalogue but finally excluded for its discrepant redshift and the consequent uncertainty on its absolute magnitude. This system is presented in Appendix A.

Our observations were carried out in 1997 at the 1.93 m telescope with the Carelec spectrograph in long slit mode at the Cassegrain focus. The grating dispersion was 260 Å/mm, corresponding to $\sim$7 Å with the $512\times512$ pixels of the Tektronix CCD. Data reduction was performed with IRAF; calibrations were done using the OHP He-Ar lamps. Redshifts were measured with xcsao in the rvsao package, using 5 star templates and attributing to each galaxy the redshift given by the best-fitting template (i.e. the one with the highest R parameter, see Tonry & Davis 1979). One velocity standard star and one galaxy with velocity measured from HI observations were also observed and used as a check of the zero-point calibration, cross-correlating them with a subset of our spectra and with our templates: in both cases, the redshifts were consistent within 10 km s-1.

Positions and redshifts of the observed galaxies are listed in Table 1.


 

 
Table 1: Heliocentric redshifts of galaxies in VLG fields.
Iden. RA (J2000) Dec (J2000) Vh (km s-1) Error Notes
VLG 061 02 30 42.7 -02 56 21 5719 31  
1 02 30 32.1 -02 53 07 5950 24 Emission lines
2 02 30 44.7 -02 53 58 5488 36  
3 02 30 46.4 -02 57 06 5561 28  
4 02 30 47.6 -02 54 32 5870 20 Emission lines
5 02 30 48.9 -02 56 46 5189 91  
6 02 31 11.6 -02 56 35 5847 31 m=15.76
7 02 30 21.9 -02 59 07 12 498 56  
VLG 068 03 25 11.5 -06 10 52 9933 48 V=10 107 m=13.97
MRK 0609 03 25 25.3 -06 08 38 10 264 57 V=10236
MRK 0610 03 25 31.4 -06 07 43 10 408 55 V=10301
VLG 074a 04 08 07.4 -08 49 45 9930 50 NGC 1516A
VLG 074b 04 08 08.2 -08 50 06 9864 45 NGC 1516B
1 04 07 45.3 -08 44 26 10 073 37  
2 04 07 59.0 -08 50 24 36 482 61  
3 04 08 00.3 -08 49 24 46 248 65 ${\rm H}_\beta$, [OIII]4959 & 5007
4 04 08 06.4 -08 48 04 36 342 101  
5 04 08 12.1 -08 56 11 42 342 95  
6 04 08 21.1 -08 47 20 36 254 45  
VLG 0716+5323 07 16 41.2 53 23 09 19 069 41 m=14.0, V=19307, X-ray
1 07 16 19.9 53 21 51 137 17 Star
2 07 16 21.2 53 21 59 19 048 32  
3 07 16 24.4 53 21 37 19 573 25  
4 07 16 32.0 53 23 45 18 330 44  
5 07 16 38.1 53 15 38 19 781 47  
6 07 16 40.0 53 22 23 19 904 43  
7 07 16 43.1 53 22 55 20 522 73  
8 07 16 47.9 53 22 45 19 066 57  
9 07 17 29.2 53 24 45 19 043 42  


2.2 2dFGRS data

Part of the SSRS2 region is covered by the 2dFRS (see Colless et al. 2001), and we searched for galaxies around VLG positions in the presently available public catalogue (the "100k'' catalogue[*], including more than 102 000 redshifts).

The limiting magnitude of the 2dFGRS is bJ=19.45; within the maximum distance defined by the SSRS2 VLG volume-limited sample ($\sim$0.065), the 2dFGRS is volume-limited at M=-17 (of course the field incompleteness has to be taken into account).

We selected all galaxies in the 2dFGRS within a projected separation less than 1.5h-1 Mpc  and a velocity difference less than 1500 km s-1 with respect to the SSRS2 VLGs. The velocity cut was chosen to limit foreground and background contamination, but large enough to include also marginal members. We also applied a 3-$\sigma$ clipping (see e.g. Yahil & Vidal 1977) to the velocity distribution. The chosen value of the projected radius corresponds to one Abell radius and it is also used as a criterion for determining the Local Group membership (van den Bergh 1999). We found data for 19 VLG fields: in 4 cases (VLG 003, VLG 008, VLG 054, VLG 075) we could retrieve only one redshift (in addition to the VLG) with our selection limits. Such cases deserve a more careful study and we will not include them in the present work. We simply note here that VLG 075 is in a group identified in the Las Campanas Redshift Survey (Tucker et al. 2000). In the other 15 fields we could obtain at least 5 redshifts (reduced to 3 by the 3$\sigma$ clipping in the case of VLG 022).

The images of the fields centered on the selected VLGs (30 arcmin size in $\delta$) were retrieved from the Digitized Sky Survey and are shown in Figs. 1 and 2. In Appendix B and in tables available in electronic form we give positions and redshifts of the 2dFGRS galaxies selected according to the criteria defined above.

3 Properties of the VLG systems

We have calculated the mean redshift and the velocity dispersion for each VLG system; the main properties are shown in Table 2, where we list in Col. (1) the VLG number, in Col. (2) the VLG morphological type, in Col. (3) the total number of galaxies after applying the 3-$\sigma$ clipping and used for measuring the mean redshift and velocity dispersion, in Col. (4) the mean heliocentric redshift with its error, in Col. (5) the velocity dispersion, in Col. (6) the system type, when available from the literature.

With respect to the known systems listed in Table 2 of our Paper I, we could associate other 8 VLGs to galaxy systems, and increase the number of measured velocity dispersions: in fact only VLG 086 (in an Hickson compact group) and VLG 108 (in the ACO cluster A4038) had already an estimate of the velocity dispersion.


 

 
Table 2: Properties of the VLG systems.
Ident. Type Nz $\bar{z}$ $\sigma_r$ (km s-1) System Type
14 Sbc 14 $0.0389 \pm 0.0007$ 747  -114  +204 Triplet
22 S0 3 $0.0570 \pm 0.0003$ $137 \pm 66$ SCG55
31 D 15 $0.0536 \pm 0.0007$ 720  -107  +188 A151
40 S 10 $0.0403 \pm 0.0008$ 724  -127  +256 --
43 Sb 15 $0.0567 \pm 0.0004$ 468  -72  +123 --
45 S 21 $0.0572 \pm 0.0004$ 464  -62  +97 --
48 Sbc 20 $0.0584 \pm 0.0003$ 378  -53  +82 Binary
53 S0 33 $0.0575 \pm 0.0002$ 360  -41  +57 --
61 SB(rs)c 7 $0.0193 \pm 0.0004$ 318  -67 +177 --
68 S Sy1 3 $0.0340 \pm 0.0004$ $236 \pm 99$ SSRS2 group
69 SB(s)b p 8 $0.0376 \pm 0.0002$ 158  -46 +79 Binary
74 S 3 $0.0332 \pm 0.0003$ $104 \pm 56$ Binary
83 E 31 $0.0580 \pm 0.0002$ 319  -38  +53 S0983
86 SB(s)bc p:Sy 37 $0.0231 \pm 0.0004$ 669  -68  +96 HCG91
93 Sb 15 $0.0566 \pm 0.0005$ 550  -83  +144 --
94 SAB(rs)p 39 $0.0336 \pm 0.0002$ 413  -43  +59 EDCC155
108 cD 114 $0.0297 \pm 0.0002$ 659  -41  +49 A4038
109 E 13 $0.0492 \pm 0.0003$ 297  -52  +89 S1155
VLGN 0716+5323 E  9 $0.0645 \pm 0.0007$ 609 +234 -109 Z1261


In Fig. 3 we show the velocity histograms of the systems with at least 10 measured redshifts. The redshift of the VLG is indicated by a dashed line.

From Table 2, and also taking into account the 4 VLGs not included in this selection, it appears that all VLGs have companions. This is not so surprising, given the known correlation between galaxies, and confirms the idea that there are no truly "isolated'' galaxies. Moreover, it is quite striking that in the literature 6 out of the 18 SSRS2 VLGs were not associated to any system, while other 3 were classified simply as binaries: for example, VLG 048 belongs to a system for which we could collect 15 new redshifts from the 2dFGRS. Such a high number of nearby galaxy systems which were not previously identified neither in the optical nor in the X-ray reminds us how poorly known the low-mass end of galaxy systems is. Therefore it is interesting to examine in more detail the nature and environment in which VLGs are found. In the following, we briefly describe the main properties of the selected VLGs and their systems.

4 The relation between VLGs and their environment

In Paper I we have shown that the correlation function of VLGs approaches that of clusters. Various galaxies discussed above (VLG 045, VLG 048, VLG 053) are within the Pisces-Cetus Supercluster, which appears as a prominent feature near the limiting depth of the SSRS2 volume-limited sample of VLGs (the presence of this structure might explain the excess of the VLG correlation amplitude measured in the SSRS2 with respect to the 2dFGRS). The Pisces-Cetus supercluster is well traced by Abell and ACO clusters (Tully 1986), but none of our VLGs is a member of those clusters. The VLG correlation function is large because VLGs trace large-scale fluctuations just as clusters do, not because they are in rich clusters.

Another interesting issue is the luminosity function of the VLG systems. In principle, merging should have played a major role in the formation of the elliptical VLGs, and the luminosity function of the associated system might be different from those dominated by a spiral VLG. As a preliminary test, we have estimated the composite luminosity functions of early and late VLG dominated systems, excluding both rich clusters and systems with probable field contamination. In this rough comparison, we assume that selection effects are the same for the two types of systems. We have normalized numbers to the total number of galaxies in the two samples (66 for spiral VLG and 71 for elliptical VLG systems). In deriving absolute magnitudes, we applied the mean $K {\mbox +} e$ correction formula K = 0.03 z /(0.01+z4) adopted by Norberg et al. (2001); at the distances of SSRS2 VLGs ($\sim 0.05$), it is consistent with the correction adopted for the SSRS2 (da Costa et al. 1994; K = 3z). As apparent from Fig. 4, taking into account the small number of objects in our samples we cannot find significant differences between the two luminosity functions to M=-17, the absolute limiting magnitude at which galaxies around SSRS2 VLGs could still be detected in the 2dFGRS.


  \begin{figure}
\par\epsfxsize=8.8cm \epsfbox{lumifun.eps}\end{figure} Figure 4: Normalized luminosity function of systems with an early type VLG (red squares) and a late type VLG (blue triangles), with Poissonian $1 \sigma $ error bars.

There is however a difference when looking at the morphology of the central VLG and the velocity dispersion of the associated system. It is not surprising that the VLGs which are at the center of clusters are giant ellipticals; these clusters have $\sigma \sim 600$ km s-1 and an associated X-ray emission at a temperature consistent with their velocity dispersion. Other 3 systems including an early type VLG (one S0 and two ellipticals) have velocity dispersions in the range 300-350 km s-1, and might be considered the low-mass end of galaxy clusters. The remaining S0 in the sample is in a compact group with a small velocity dispersion ($\sim$140 km s-1).

The systems dominated by a spiral VLG have a large spread in velocity dispersion: but as we have seen from the velocity histograms, those with the largest velocity dispersions ($\sim$700 km s-1), VLG 014, VLG 040 and VLG 086, are probably affected by field contamination. Moreover, for these systems no extended X-ray emission is reported in the on-line databases.

Within the limits of the small statistics and lack of completeness, we can conclude that VLGs are in a qualitative agreement with the morphology-density relation: in clusters and rich groups we find only early type VLGs, while among systems originally classified as binaries or triplets, and those with the lowest velocity dispersions (with the exception of the S0 VLG 022) the VLG is a late-type.

The nearby systems we have observed at OHP have lower velocity dispersions, and have probably also a lower richness but the limiting apparent magnitude is also brighter for these systems. The system more similar to our own Local Group is the one associated to VLG 069. It has 10 galaxies with measured redshifts and $M_B \le -15.5$: even if this is still not a complete sample, the number is comparable to the Local Group, where we find 10 galaxies with $M_V \le -15.5$. VLG 069 is the main member of a binary system, as Andromeda and the Milky Way; moreover, the VLG 069 system has also a relatively low velocity dispersion, $\sigma \sim 160$ km s-1, still somewhat higher than the velocity dispersion of the Local Group, $\sigma=61 \pm 8$ km s-1 (van den Bergh 1999, 2000), which is indeed lower than the observed range of our VLG systems. However, our observational errors would not allow us to measure accurately such a low velocity dispersion.

Our optical classification of VLG systems can be compared to the X-ray based classification of galaxy groups by Zabludoff & Mulchaey (1998), who distinguish groups with a bright, central elliptical galaxy and smooth X-ray emission from the hot IGM, and groups without X-ray emission, a few bright late-type galaxies with fainter members, like our Local Group. Our systems with an early-type VLG have generally velocity dispersion and richness comparable to the values found by ZM98 for their 9 poor groups with diffuse X-ray emission. They also find that the 3 groups without X-ray emission have a lower number of members, which seems also consistent with what we find. Zabludoff (2000) has suggested the possibile existence of a third class of groups in a transition phase, but it has still to be demonstrated that the differences between the two classes might be due to evolution instead of their different formation processes.

5 Discussion and conclusions

The number density of galaxies is dominated by faint, small systems. As an example, let us assume a Schechter luminosity function with M* bJ=-19.6, $\alpha=-1.22$ and $\phi^*=0.02$ (Zucca et al. 2000). The fraction of galaxies brighter than L* is in fact less than 2% of all galaxies with $M_{b_J} \leq -12.5$. The brightest galaxies with $M_{b_J} \leq -21$ are only 3 out of 10 000. Among these galaxies, we find M 31 and probably the Milky Way (see e.g. van den Berg 1999), which are therefore not typical galaxies, but very special systems. Nevertheless, when looking at the luminosity (mass) density, the contribution of Very Luminous Galaxies (VLGs) with $M_B \leq -21$ to the luminosity density increases to 1.6% and that of M* galaxies to nearly 30%. VLGs are extremely interesting from the point of view of galaxy formation and large-scale structure. They are visible at large distances ( $D_{\rm max} \sim 170$h-1 Mpc  at the limiting magnitude of the SSRS2 mB=15.5) and their distribution is biased with respect to galaxies of lower luminosity.

There is a common misconception according to which optically very luminous galaxies selected with a large correlation amplitude are early-type galaxies in clusters. In this work we have shown that, at least choosing galaxies in the blue passband, this is not the case. We have presented our observations and 2dFGRS data concerning fields centered on SSRS2 VLGs: we have found clear evidence that VLGs are the brightest members of galaxy systems which can escape standard group finding methods, except of course for the minority of early-type VLGs in rich groups or clusters. VLGs have clustering properties similar to clusters, but most of them are in systems with a galaxy population comparable to loose groups, and some of them are probably comparable to our Local Group. The large correlation amplitude suggests that VLGs are in high density regions; most of them, being spirals, cannot have accreted more than a few percent of their mass through major merging episodes (Tóth & Ostriker 1992), so we have to suppose that these systems already formed with a large, central massive galaxy and low mass companions. On the other hand, the merging of two late-type VLGs could evolve into an early type system, analogously to what was suggested for poor groups by Zabludoff & Mulchaey (2000).

Other recent works appear to confirm the general properties of VLGs which we have found from the analysis of the SSRS2. Giuricin et al. (2001) have analysed the Nearby Optical Galaxy sample, finding a similar trend for the luminosity segregation, and that only 10% of their VLGs reside in clusters; they also find that, while the fraction of very luminous early-type galaxies is larger than the corresponding fraction for the total sample, it is still only 29%, less than than the fraction of Scd galaxies (39%). Moreover, from the analysis of the 2dFGRS Norberg et al. (2002) confirm that "luminosity, and not type, is the dominant factor in determining how the clustering strength of the whole galaxy population varies with luminosity''.

The amount of mass associated to VLG systems is still an open question. For example, the lower correlation amplitude for VLGs found in the 2dFGRS would indicate that VLGs are associated to dark halos less massive than typical halo clusters. The increase in local overdensity of galaxies around VLGs should also be better determined. In a recent paper Hogg et al. (2003) analyse the Sloan Digital Sky Survey and find the intriguing results that blue luminous galaxies with L < 3 L* are not apparently found in overdensities, but VLGs have even larger luminosities.

Therefore only further and deeper observations devoted to the detailed study of VLGs, determining the luminosity function of these systems and the dynamics of satellites around the VLGs, together with observations in redder passbands (more representative of the mass of the systems) will shed more light on the properties of VLGs and their environment, and their implications for galaxy formation and evolution.

Acknowledgements
This work has been partially supported by the Italian Space Agency grants ASI-I-R-105-00 and ASI-I-R-037-01, and by the Italian Ministery (MIUR) grant COFIN2001 "Clusters and groups of galaxies: the interplay between dark and baryonic matter". We thank the referee, Florence Durret, for her careful reading of the manuscript and useful comments.

Appendix A: The discrepant redshift of Arp 127


 

 
Table A.1: Heliocentric redshifts of galaxies in Arp 127.
Iden. RA (2000) Dec (2000) Vh (km s-1) Error Bt Notes
NGC 0191 00 38 59.3 -09 00 09  6076  32 12.5 [13.68]
IC 1563 00 39 00.2 -09 00 53  6138  39 14.74 [14.39]
0039-0931 00 39 02.0 -09 00 31 13 652 141  


The Arp 127 pair (Arp 1966) is made by NGC 0191, a spiral classified as SAB(rs)c: pec, and IC 1563, an S0 pec sp. A third, more compact object is seen among the two galaxies (see Fig. A.1). According to the literature, the redshifts of NGC 0191 and IC 1563 are respectively $v=5065 \pm 141$ km s-1 and $v=13~652 \pm 141$ km s-1 (Huchra et al. 1993), a surprising difference given the apparent signs of interactions; for this reason IC 1563 was not included in our final catalogue, even if according to the quoted redshift and the apparent magnitude (m = 14.74) it should be considered a VLG.


  \begin{figure}
\par {\epsfxsize=8.0cm \epsfbox{tvArp127.eps} }
\end{figure} Figure A.1: Arp 127: finding chart (the scale is $8 \times 8$ square arcmin).

Our measurements for NGC 0191 and IC 1563 are reported in Table A.1, and show that there is no discrepancy: the binary system Arp 127 is at $z \sim 6150$ km s-1, and the two galaxies have a velocity difference of only $\sim$60 km s-1 -, i.e. they have the same velocity taking into account the errors. These two galaxies are clearly interacting, as shown by the tidal distortion in NGC 0191.

We suggest that the redshift of 13 652 km s-1 should be attributed to the round object between the two galaxies. In fact Beers et al. (1991) report that value for the redshift giving the coordinates of the round object, but identify it as IC 1563, while Huchra et al. (1993) give the approximate coordinates of the Arp 127 system for both NGC 0191 and IC 1563. The velocity of the round object is in the lower part of the velocity range of the A85 galaxy cluster (see Durret et al. 1998) and at an angular distance of 44 arcmin from its center, and it might be a galaxy member of the cluster.

The new redshift for IC 1563 means that this galaxy has M=-19.2, i.e. it is a typical M* galaxy and not a VLG. In Table A.1 we report also the photometric observations of Reshetnikov & Combes (1996).

References

  
6 Online Material


  \begin{figure}
\par\centerline
{\hskip 3cm VLG061: finding chart. \hskip 6.6cm ...
...VLG074.eps}\hskip 1cm
\epsfxsize=8.0cm \epsfbox{tvVLGN07+53.eps} }
\end{figure} Figure 1: Finding charts of the VLG fields observed at OHP (the scale is approximately $30 \times 30$ square arcmin).


  \begin{figure*}
\par\centerline
{\hskip 3.5cm VLG014 \hskip 7.1cm VLG022}
\mbox...
...x{VLG043.eps}\hskip 1cm
\epsfxsize=8.0cm \epsfbox{VLG045.eps} }
\end{figure*} Figure 2: Finding charts of the VLG fields selected from the 2dFGRS (the scale is approximately $40 \times 30$ square arcmin).


  \begin{figure*}\centerline
{\hskip 5cm VLG048 \hskip 7.1cm VLG053}
\mbox{\epsfx...
...{VLG086.eps}\hskip 1cm
\epsfxsize=8.0cm \epsfbox{VLG093.eps} }
\end{figure*} Figure 5: aa


  \begin{figure*}\centerline
{\hskip 5cm VLG094 \hskip 7.1cm VLG108}
\mbox{\epsfx...
...p 7.1cm}
\mbox{\epsfxsize=8.0cm \epsfbox{VLG109.eps}\hskip 1cm}
\end{figure*} Figure 6: bb

Appendix B: 2dFGRS data

In the following tables we list the 2dFGRS galaxies which we have selected as members of VLG systems. We give in Col. (1) our identification number, in Cols. (2) and (3) respectively right ascension and declination, in Col. (4) the bJ magnitude, and in Col. (5) the redshift.

We have listed the 2dFGRS data on the VLG when available, otherwise we have reported the SSRS2 data.

We could compare magnitudes and redshifts of the 2dFGRS and SSRS2 for 5 VLGs with 2dFGRS data (VLG 014, VLG 022, VLG 043, VLG 045, VLG 048, VLG 109): we find an average velocity difference <V (2dF) - V (SSRS2)> = 118 km s-1 with an rms of 155 km s-1 and an average magnitude difference <bJ (2dF) - mB (SSRS2)> = 0.20, with an rms of 0.46. The magnitude difference is consistent with the $\sim 0.2$ zero-point shift expected between the blue magnitudes of the SSRS2 (Alonso et al. 1993, 1994; da Costa et al. 1994) and the APM bJ magnitudes on which the 2dFGRS is based (Maddox et al. 1990, 1990, 1996). Note that for bright galaxies, magnitudes are not very precise: the APM bJ magnitudes have a precision of 0.2 in the range 17-19.5 but are significantly affected by saturation at magnitudes brighter than bJ = 16 (Norberg et al. 2002).


   
Table B.1: VLG 014 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 00 49 16.58 -27 15 02.3 17.04 0.03514  
2 00 49 32.12 -27 40 00.1 18.14 0.04093  
3 00 49 45.62 -27 45 15.2 16.65 0.04012  
4 00 49 57.81 -26 55 11.7 18.86 0.04342  
5 00 50 20.18 -27 47 36.3 17.41 0.03942  
6 00 50 21.56 -27 37 15.5 18.74 0.04076  
7 00 51 03.74 -27 41 06.2 17.43 0.03996  
8 00 51 27.98 -27 38 24.5 16.89 0.04005  
9 00 52 15.02 -27 19 41.4 15.17 0.03983 VLG014
10 00 52 15.58 -27 01 35.9 18.13 0.03534  
11 00 52 15.64 -27 20 58.1 15.62 0.04005  
13 00 52 25.52 -26 59 17.6 16.96 0.03553  
13 00 52 40.97 -27 15 51.2 18.21 0.03498  
14 00 53 11.23 -26 47 31.7 19.32 0.03946  


   
Table B.2: VLG 022 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 00 58 52.33 -28 18 11.9 15.64 0.05753 VLG022
2 00 58 55.81 -28 19 30.2 16.53 0.05703  
3 01 00 58.93 -28 21 39.9 19.28 0.05640  


   
Table B.3: VLG 031 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 01 07 17.22 -15 04 48.0 18.55 0.05560  
2 01 07 41.81 -14 54 56.7 18.06 0.05044  
3 01 08 09.82 -15 12 18.7 17.13 0.05197  
4 01 08 16.05 -14 52 07.8 17.05 0.05272  
5 01 08 30.64 -14 57 04.7 16.07 0.05112  
6 01 08 32.40 -15 03 10.4 18.21 0.05184  
7 01 08 32.44 -15 08 54.6 18.26 0.05371  
8 01 08 50.70 -15 24 32.2 14.36 0.05326 VLG031; data from SSRS2
9 01 09 40.52 -14 55 50.5 17.47 0.05813  
10 01 10 15.95 -15 18 17.3 17.28 0.05563  
11 01 10 20.67 -15 18 08.1 17.44 0.05439  
12 01 10 21.68 -15 15 22.1 18.09 0.05634  
13 01 10 25.17 -15 15 24.8 15.39 0.05666  
14 01 10 26.38 -15 18 57.4 17.59 0.05309  
15 01 10 27.46 -15 06 43.1 17.58 0.04893  


   
Table B.4: VLG 040 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 01 37 40.78 -28 37 01.9 16.83 0.04254  
2 01 38 20.37 -28 38 58.5 17.61 0.04307  
3 01 38 40.39 -28 57 17.6 19.23 0.04067  
4 01 38 56.46 -28 35 08.7 18.96 0.04261  
5 01 38 59.71 -28 34 21.2 14.64 0.04212 VLG040; data from SSRS2
6 01 39 21.29 -29 00 42.2 17.28 0.04205  
7 01 41 07.26 -29 07 42.7 18.16 0.03683  
8 01 41 47.60 -28 12 26.4 19.37 0.03812  
9 01 41 48.65 -28 31 28.7 17.00 0.03724  
10 01 41 55.43 -28 32 53.0 15.77 0.03768  


   
Table B.5: VLG 043 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 01 38 44.44 -27 50 47.4 16.50 0.05666  
2 01 39 17.85 -27 49 05.0 17.17 0.05702  
3 01 39 21.51 -27 48 47.1 19.21 0.05596  
4 01 39 36.50 -28 25 41.6 19.14 0.05888  
5 01 39 51.04 -27 48 51.9 19.00 0.05674  
6 01 39 57.12 -27 57 21.7 15.63 0.05640 VLG043
7 01 40 03.08 -27 59 04.0 18.05 0.05652  
8 01 40 31.09 -28 04 36.2 19.14 0.05924  
9 01 40 39.96 -27 28 58.6 18.82 0.05372  
10 01 40 55.41 -27 49 40.2 18.62 0.05915  
11 01 41 30.07 -27 46 31.8 17.52 0.05704  
12 01 41 37.09 -27 45 33.0 18.61 0.05658  
13 01 41 42.11 -27 40 18.1 17.03 0.05687  
14 01 41 44.35 -28 07 23.1 19.43 0.05319  
15 01 42 19.91 -27 59 36.8 18.75 0.05674  


   
Table B.6: VLG 045 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 01 48 02.03 -28 49 30.2 19.00 0.05580  
2 01 48 37.65 -29 03 18.1 18.34 0.06024  
3 01 49 00.27 -28 36 28.9 17.32 0.05612  
4 01 49 05.17 -28 33 57.5 17.00 0.05547  
5 01 49 12.19 -28 37 10.2 18.86 0.05607  
6 01 49 22.26 -28 57 38.4 18.04 0.05604  
7 01 49 40.19 -29 15 21.7 19.04 0.05552  
8 01 50 05.55 -28 49 54.0 18.56 0.05576  
9 01 50 06.99 -28 49 17.0 18.36 0.05756  
10 01 50 08.49 -28 45 46.1 18.20 0.05769  
11 01 50 14.15 -28 52 18.0 14.96 0.05759 VLG045
12 01 50 20.74 -29 05 32.0 18.83 0.05736  
13 01 50 43.56 -28 58 56.4 17.04 0.05606  
14 01 50 44.60 -29 11 10.0 17.92 0.06084  
15 01 51 00.56 -28 54 27.9 16.66 0.05802  
16 01 51 01.84 -29 15 35.9 18.64 0.05592  
17 01 51 04.92 -28 59 50.8 19.41 0.05723  
18 01 51 11.10 -28 54 42.2 17.54 0.05622  
19 01 51 32.85 -28 29 32.6 18.04 0.05681  
20 01 51 35.00 -28 55 42.8 18.70 0.06092  
21 01 51 39.92 -28 30 14.8 19.09 0.05707  


   
Table B.7: VLG 048 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 01 53 13.63 -27 54 33.2 19.06 0.05883  
2 01 53 16.97 -27 49 32.7 17.14 0.06007  
3 01 53 34.87 -28 34 07.0 17.54 0.05741  
4 01 53 55.02 -28 14 37.4 19.32 0.05816  
5 01 54 11.90 -28 23 02.1 17.01 0.05745  
6 01 54 12.78 -27 51 57.1 16.90 0.06024  
7 01 54 13.11 -27 52 19.7 17.94 0.05717  
8 01 54 26.25 -27 47 43.0 18.43 0.06103  
9 01 54 27.30 -27 51 08.0 19.30 0.06021  
10 01 54 29.09 -28 27 22.4 17.76 0.05686  
11 01 54 39.87 -27 59 20.8 18.40 0.06010  
12 01 54 41.67 -28 10 10.2 19.31 0.05614  
13 01 54 48.16 -28 11 45.5 19.13 0.05954  
14 01 54 48.72 -28 08 56.8 15.66 0.05726 VLG048
15 01 55 03.18 -28 12 57.9 18.96 0.05750  
16 01 55 09.03 -27 41 35.3 19.45 0.05734  
17 01 55 15.56 -28 11 37.6 18.81 0.05818  
18 01 55 39.26 -27 53 56.5 19.10 0.05897  
19 01 55 49.42 -28 00 13.2 17.53 0.05813  
20 01 56 35.77 -27 55 39.7 19.32 0.05789  


   
Table B.8: VLG 053 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 02 11 25.59 -26 49 51.0 17.93 0.05572  
2 02 11 48.77 -26 35 24.5 18.28 0.05744  
3 02 12 07.18 -26 46 18.8 16.03 0.05566  
4 02 12 07.92 -26 49 38.9 17.72 0.05555  
5 02 12 27.64 -26 38 18.4 18.76 0.05903  
6 02 12 36.11 -26 30 03.9 17.25 0.05513  
7 02 12 36.71 -26 38 29.8 18.46 0.05650  
8 02 12 40.02 -26 29 11.6 18.10 0.05770  
9 02 12 40.28 -26 45 21.8 19.04 0.05890  
10 02 12 43.66 -26 09 50.9 17.70 0.05882  
11 02 12 44.45 -26 27 28.1 19.16 0.05765  
12 02 12 49.00 -26 27 35.0 15.16 0.05695 VLG053; data from SSRS2
13 02 12 51.77 -26 24 39.8 18.56 0.05715  
14 02 12 52.89 -26 47 58.4 15.15 0.05634  
15 02 12 53.46 -26 39 42.3 18.70 0.05724  
16 02 12 54.13 -26 25 20.2 17.02 0.05721  
17 02 12 57.90 -26 42 24.9 18.37 0.05536  
18 02 13 04.47 -26 40 04.4 18.56 0.05652  
19 02 13 08.44 -26 30 11.9 18.62 0.05749  
20 02 13 27.83 -26 48 41.7 18.38 0.05891  
21 02 13 31.14 -26 25 39.3 19.21 0.05916  
22 02 13 35.09 -26 34 47.2 17.00 0.05752  
23 02 13 38.35 -26 50 23.4 19.34 0.05890  
24 02 13 45.41 -26 49 17.1 18.78 0.05958  
25 02 13 46.08 -26 46 12.7 17.96 0.05881  
26 02 14 02.66 -26 27 38.3 16.82 0.05832  
27 02 14 06.69 -26 31 21.9 18.30 0.05605  
28 02 14 07.28 -26 29 43.4 18.80 0.05658  
29 02 14 22.41 -26 39 48.9 16.69 0.05909  
30 02 14 33.71 -26 28 02.9 18.24 0.05676  
31 02 14 46.39 -26 35 14.0 18.70 0.05941  
32 02 14 51.04 -26 39 37.1 15.77 0.05784  
33 02 14 58.37 -26 16 18.9 18.87 0.05661  


   
Table B.9: VLG 069 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 03 29 13.06 -28 07 47.8 19.37 0.03771  
2 03 29 20.35 -28 09 10.5 18.78 0.03778  
3 03 29 20.92 -28 08 00.9 14.22 0.03773  
4 03 29 32.13 -28 09 35.4 16.55 0.03818  
5 03 29 56.13 -28 46 14.5 14.09 0.03647 companion of the VLG?
6 03 29 56.79 -28 46 29.8 13.95 0.03687 VLG069; data from SSRS2
7 03 29 58.84 -28 43 35.5 15.23 0.03830  
8 03 30 11.98 -28 59 49.0 19.20 0.03778  


   
Table B.10: VLG 083 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 21 58 44.19 -19 05 08.0 17.22 0.05913  
2 21 58 49.05 -19 09 46.3 18.51 0.05877  
3 21 58 55.66 -19 03 13.7 19.04 0.05817  
4 21 58 57.89 -19 20 14.5 17.03 0.05751  
5 21 59 10.30 -19 17 13.3 17.78 0.05682  
6 21 59 10.32 -19 24 23.5 18.91 0.05777  
7 21 59 19.18 -19 22 53.1 15.76 0.05814  
8 21 59 31.49 -19 06 59.1 18.34 0.05715  
9 21 59 36.35 -19 22 03.7 18.45 0.05788  
10 21 59 40.51 -19 10 40.1 18.32 0.05752  
11 21 59 43.73 -19 16 26.5 19.16 0.05901  
12 21 59 48.86 -19 20 01.8 18.14 0.05814  
13 21 59 52.95 -19 04 50.0 18.70 0.05691  
14 21 59 56.81 -19 06 06.6 19.01 0.05808  
15 22 00 04.31 -19 09 58.3 19.18 0.05778  
16 22 00 05.40 -19 12 16.0 15.48 0.05858 VLG083; data from SSRS2
17 22 00 07.52 -19 12 38.5 17.93 0.05731  
18 22 00 10.74 -19 02 48.0 18.20 0.05872  
19 22 00 13.16 -18 50 12.4 19.19 0.05848  
20 22 00 22.42 -18 43 14.8 18.99 0.05777  
21 22 00 24.22 -19 09 11.0 16.90 0.05830  
22 22 00 49.05 -19 00 57.6 17.65 0.05588  
23 22 00 55.20 -19 19 58.5 18.74 0.05701  
24 22 00 56.22 -19 09 11.8 19.15 0.05646  
25 22 01 04.69 -19 01 04.6 16.84 0.05713  
26 22 01 28.62 -19 23 53.1 17.34 0.05860  
27 22 01 34.80 -19 26 41.1 18.37 0.05715  
28 22 01 43.74 -19 19 19.4 17.46 0.05709  
29 22 01 56.98 -19 22 54.9 17.99 0.05755  
30 22 02 05.65 -19 23 45.2 17.24 0.05694  


   
Table B.11: VLG 086 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 22 03 38.55 -27 58 32.7 18.02 0.02329  
2 22 03 41.79 -27 56 07.2 15.03 0.02014  
3 22 03 45.74 -27 47 52.5 15.50 0.02327  
4 22 03 54.11 -27 51 30.5 19.14 0.02155  
5 22 04 03.25 -27 29 38.5 16.18 0.02316  
6 22 04 57.79 -28 05 18.4 19.01 0.02291  
7 22 06 14.11 -27 57 14.8 14.32 0.02400  
8 22 06 21.29 -27 35 22.0 17.69 0.02014  
9 22 06 34.06 -27 59 30.8 14.99 0.02287  
10 22 06 36.75 -27 48 05.3 18.89 0.02312  
11 22 06 38.17 -27 57 24.7 17.65 0.02331  
12 22 07 27.04 -27 55 34.9 18.67 0.02309  
13 22 07 33.04 -27 44 51.8 18.98 0.02066  
14 22 07 57.11 -28 15 01.2 16.43 0.02593  
15 22 08 12.28 -27 05 56.1 16.83 0.01956  
16 22 08 26.36 -28 13 07.7 19.21 0.02689  
17 22 08 33.09 -27 56 12.1 18.88 0.02331  
18 22 08 50.20 -26 54 05.3 18.25 0.01885  
19 22 09 07.45 -27 48 22.8 14.19 0.02298  
20 22 09 07.68 -27 48 34.1 13.05 0.02279 VLG086; data from SSRS2
21 22 09 13.08 -27 34 03.9 15.70 0.02352  
22 22 09 14.08 -27 46 57.1 14.66 0.02431  
23 22 09 14.28 -27 24 11.8 14.98 0.02373  
24 22 09 16.29 -27 43 50.0 15.09 0.02398  
25 22 09 38.77 -27 33 18.2 19.00 0.02481  
26 22 09 43.74 -27 35 56.1 18.48 0.02359  
27 22 09 47.10 -26 53 02.7 18.91 0.02141  
28 22 09 50.52 -27 32 06.0 15.18 0.02450  
29 22 09 52.15 -27 37 53.8 19.03 0.02586  
30 22 11 52.69 -27 18 45.2 19.15 0.02410  
31 22 12 20.97 -27 29 17.1 15.93 0.02374  
32 22 12 29.62 -27 54 17.8 18.65 0.02740  
33 22 13 23.04 -27 56 01.9 18.34 0.02404  
34 22 13 23.52 -27 13 10.6 14.00 0.02375  
35 22 13 28.77 -28 07 17.6 19.05 0.02691  
36 22 13 56.58 -27 30 31.3 17.21 0.01765  
37 22 14 39.41 -27 27 52.0 13.97 0.01789  


   
Table B.12: VLG 093 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 22 29 45.57 -30 28 30.1 18.88 0.05894  
2 22 29 49.89 -30 12 24.9 18.62 0.05316  
3 22 29 50.60 -30 31 02.9 14.73 0.05356 VLG093; data from SSRS2
4 22 29 55.77 -30 32 39.7 18.06 0.05389  
5 22 30 11.21 -30 21 19.5 19.32 0.05700  
6 22 30 15.05 -30 47 03.4 18.35 0.05868  
7 22 30 17.94 -30 44 42.8 17.93 0.05788  
8 22 30 21.04 -30 51 48.2 19.14 0.05832  
9 22 30 23.39 -30 40 56.3 18.69 0.05686  
10 22 30 29.91 -30 59 31.5 18.07 0.05709  
11 22 30 36.86 -30 16 37.8 19.21 0.05513  
12 22 30 37.17 -30 37 41.3 17.81 0.05815  
13 22 30 41.06 -30 26 09.7 18.83 0.05492  
14 22 30 50.02 -30 24 01.5 19.06 0.05778  
15 22 31 02.16 -30 43 12.8 18.28 0.05793  


   
Table B.13: VLG 094 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 22 29 36.48 -25 01 38.5 17.52 0.03260  
2 22 29 42.08 -25 27 31.0 19.13 0.03231  
3 22 30 04.41 -24 59 05.2 17.98 0.03186  
4 22 30 07.11 -24 58 22.4 14.56 0.03116  
5 22 30 12.09 -25 18 47.6 19.25 0.03302  
6 22 30 23.82 -25 28 10.0 18.24 0.03317  
7 22 30 35.88 -24 36 56.9 17.77 0.03363  
8 22 30 44.70 -25 43 14.6 18.85 0.03620  
9 22 30 57.29 -25 10 45.9 15.75 0.03384  
10 22 31 02.76 -25 20 34.8 15.12 0.03296  
11 22 31 17.61 -24 58 07.8 19.26 0.03129  
12 22 31 17.97 -24 43 58.5 15.98 0.03410  
13 22 31 27.37 -25 15 41.5 18.41 0.03502  
14 22 31 31.09 -25 53 13.0 15.03 0.03458  
15 22 31 32.05 -25 25 12.9 15.79 0.03376  
16 22 31 41.06 -25 13 36.6 16.67 0.03378  
17 22 31 41.66 -25 30 21.0 18.84 0.03589  
18 22 31 49.74 -25 26 28.5 16.57 0.03190  
19 22 31 55.43 -25 30 39.9 17.04 0.03163  
20 22 31 58.81 -25 21 39.3 15.40 0.03617  
21 22 31 59.49 -25 32 55.6 16.05 0.03310  
22 22 32 03.77 -25 38 47.8 18.83 0.03435  
23 22 32 07.45 -25 24 53.4 18.35 0.03132  
24 22 32 08.10 -25 23 51.0 13.92 0.03409 VLG094; data from SSRS2
25 22 32 11.88 -26 00 19.7 18.77 0.03234  
26 22 32 13.43 -25 23 27.7 16.52 0.03406  
27 22 32 17.26 -25 13 57.4 16.99 0.03179  
28 22 32 17.77 -25 18 49.4 18.46 0.03668  
29 22 32 25.17 -25 20 33.0 18.53 0.03347  
30 22 32 26.99 -25 25 35.3 15.76 0.03632  
31 22 32 33.25 -25 16 29.4 17.15 0.03415  
32 22 32 55.19 -26 02 16.9 18.10 0.03246  
33 22 34 29.62 -25 43 07.3 15.20 0.03330  
34 22 34 49.05 -25 14 29.0 16.51 0.03396  
35 22 34 49.93 -25 36 01.7 17.20 0.03463  
36 22 35 10.71 -25 02 56.7 16.75 0.03465  
37 22 35 18.30 -25 06 56.8 15.76 0.03323  
38 22 35 26.06 -25 04 29.3 14.65 0.03409  
39 22 35 39.69 -25 06 35.8 18.45 0.03474  


   
Table B.14: VLG 108 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 23 43 15.45 -28 14 26.7 17.35 0.02836  
2 23 43 23.27 -28 11 17.9 17.80 0.02845  
3 23 43 35.67 -28 06 04.0 16.67 0.02974  
4 23 44 22.30 -28 11 44.6 17.69 0.02787  
5 23 44 38.81 -27 39 34.5 15.93 0.03031  
6 23 45 03.76 -27 59 11.9 17.99 0.02987  
7 23 45 03.84 -27 20 41.4 16.80 0.02782  
8 23 45 16.64 -27 18 57.1 18.02 0.02784  
9 23 45 28.01 -27 57 49.0 16.63 0.03058  
10 23 45 32.63 -27 37 21.8 19.36 0.02647  
11 23 45 34.49 -28 10 48.0 17.67 0.02811  
12 23 45 40.30 -27 51 48.8 16.91 0.02876  
13 23 45 41.19 -27 48 27.8 17.65 0.03093  
14 23 45 52.57 -28 02 53.0 17.86 0.03008  
15 23 45 55.71 -28 13 52.1 18.53 0.02636  
16 23 46 00.76 -27 53 44.3 17.30 0.02871  
17 23 46 16.09 -27 30 37.3 15.99 0.02933  
18 23 46 22.83 -28 00 18.4 15.34 0.02696  
19 23 46 38.39 -28 15 11.4 16.81 0.02665  
20 23 46 41.44 -27 58 04.4 18.95 0.02947  
21 23 46 43.40 -27 56 01.9 18.23 0.03097  
22 23 46 44.02 -27 50 29.2 17.93 0.03259  
23 23 46 45.76 -27 49 23.7 18.60 0.03180  
24 23 46 47.33 -27 33 21.2 17.88 0.02878  
25 23 46 49.87 -28 10 08.9 16.02 0.03251  
26 23 46 50.07 -27 57 29.1 17.96 0.03142  
27 23 46 53.00 -27 34 47.8 16.68 0.03142  
28 23 46 54.99 -28 21 42.6 15.62 0.02425  
29 23 46 58.15 -28 02 55.6 17.71 0.02706  
30 23 47 11.34 -28 14 25.5 18.00 0.02472  
31 23 47 12.08 -27 55 48.4 15.98 0.02963  
32 23 47 13.29 -28 01 03.0 16.63 0.03345  
33 23 47 14.15 -28 01 48.9 17.72 0.02826  
34 23 47 14.39 -28 11 35.7 16.62 0.02922  
35 23 47 14.80 -27 57 27.9 14.65 0.02884  
36 23 47 17.39 -28 13 37.9 18.08 0.03289  
37 23 47 20.14 -28 03 46.7 17.08 0.02787  
38 23 47 22.36 -27 58 32.6 16.79 0.02475  
39 23 47 23.22 -28 07 09.0 16.36 0.03283  
40 23 47 27.39 -27 27 56.1 16.80 0.02838  
41 23 47 28.56 -28 06 33.3 14.76 0.02792  
42 23 47 28.84 -28 08 08.3 14.81 0.02799  
43 23 47 30.17 -27 39 44.0 15.43 0.02887  
44 23 47 30.63 -28 02 35.5 17.28 0.02780  
45 23 47 30.77 -27 56 05.3 18.56 0.02733  
46 23 47 31.80 -28 06 26.1 16.43 0.02783  
47 23 47 34.67 -28 09 16.0 17.62 0.03218  
48 23 47 38.14 -27 44 45.2 18.45 0.03141  
49 23 47 41.98 -28 04 51.4 19.36 0.03049  
50 23 47 42.10 -28 07 33.8 17.25 0.02946  
51 23 47 42.33 -27 59 54.0 17.56 0.02943  
52 23 47 44.71 -27 29 13.9 14.86 0.02976  
53 23 47 45.00 -28 08 27.0 13.78 0.02916 VLG108; data from SSRS2
54 23 47 45.53 -27 49 49.3 17.98 0.03149  
55 23 47 47.16 -28 08 06.5 17.61 0.02699  
56 23 47 49.34 -28 17 28.7 17.92 0.02979  
57 23 47 49.54 -28 05 12.4 17.31 0.03214  
58 23 47 49.54 -28 12 13.8 16.99 0.03178  
59 23 47 50.41 -28 09 08.8 17.74 0.03289  
60 23 47 52.55 -28 06 13.8 18.45 0.03336  
61 23 47 55.83 -28 14 25.8 18.66 0.03174  
62 23 47 58.53 -27 56 11.5 18.94 0.03119  
63 23 48 00.86 -28 09 22.9 19.18 0.03220  
64 23 48 03.81 -27 53 01.7 18.39 0.03051  
65 23 48 05.68 -27 43 42.6 19.04 0.02868  
66 23 48 11.40 -27 55 58.6 18.54 0.03402  
67 23 48 20.23 -27 55 11.6 18.26 0.03406  
68 23 48 26.86 -27 51 20.1 17.41 0.02998  
69 23 48 27.14 -27 47 44.5 18.97 0.03304  
70 23 48 40.31 -27 52 31.3 18.78 0.03192  
71 23 48 48.75 -27 41 58.5 17.98 0.03400  
72 23 48 54.69 -27 49 03.6 17.13 0.03410  
73 23 49 05.07 -27 44 47.4 18.94 0.02661  
74 23 49 05.47 -28 50 12.3 18.87 0.02953  
75 23 49 11.19 -27 39 06.2 18.05 0.02890  
76 23 49 21.48 -28 32 30.2 16.60 0.02913  
77 23 49 33.91 -28 27 25.6 18.22 0.02695  
78 23 49 44.75 -28 15 41.9 17.65 0.02861  
79 23 49 44.76 -28 00 20.0 18.30 0.03121  
80 23 49 51.09 -27 57 01.2 14.54 0.02996  
81 23 49 57.42 -27 58 49.0 18.05 0.03364  
82 23 50 00.20 -28 11 26.1 17.02 0.03199  
83 23 50 00.69 -27 55 46.3 19.22 0.03025  
84 23 50 06.33 -27 25 46.2 18.79 0.03349  
85 23 50 20.04 -27 38 49.0 17.57 0.02885  
86 23 50 21.56 -28 20 36.1 18.60 0.02506  
87 23 50 24.70 -27 56 25.8 15.42 0.02916  
88 23 50 27.55 -28 20 23.2 18.53 0.02739  
89 23 50 30.75 -27 32 13.1 16.91 0.03411  
90 23 50 35.11 -27 47 45.2 15.62 0.02959  
91 23 50 35.65 -28 07 42.8 16.59 0.02858  
92 23 50 37.30 -28 35 54.3 18.28 0.02799  
93 23 50 37.95 -28 26 04.5 14.86 0.02839  
94 23 50 53.02 -28 03 29.9 17.44 0.02771  
95 23 51 00.47 -27 56 17.1 15.82 0.02982  
96 23 51 02.82 -27 47 51.3 16.78 0.02912  
97 23 51 03.64 -28 21 00.8 16.41 0.02757  
98 23 51 06.50 -28 09 05.5 18.04 0.02742  
99 23 51 07.01 -27 48 44.0 17.61 0.02978  
100 23 51 11.37 -28 06 06.2 19.29 0.02951  
101 23 51 19.10 -27 58 27.8 15.45 0.03360  
102 23 51 24.97 -28 35 44.8 17.11 0.02897  
103 23 51 25.67 -28 28 51.1 17.39 0.02705  
104 23 51 26.91 -28 03 07.9 17.28 0.03219  
105 23 51 35.63 -28 17 13.5 17.48 0.02817  
106 23 51 36.69 -28 21 53.2 14.40 0.02758  
107 23 51 39.58 -28 35 32.1 16.65 0.02789  
108 23 51 41.85 -28 04 26.7 18.91 0.03285  
109 23 51 48.02 -28 18 46.9 17.55 0.02933  
110 23 51 50.29 -28 17 37.6 17.21 0.02777  
111 23 51 50.36 -27 57 55.1 15.11 0.02927  
112 23 51 54.42 -27 55 48.3 14.55 0.02921  
113 23 51 54.55 -27 59 03.6 18.22 0.03317  
114 23 52 02.00 -28 11 34.5 17.41 0.03109  


   
Table B.15: VLG 109 system.
Iden. RA (J2000) DEC (J2000) bJ Redshift  
1 23 47 48.41 -28 56 38.9 18.62 0.04815  
2 23 47 56.85 -29 18 08.3 17.82 0.04885  
3 23 49 21.95 -29 10 22.2 17.46 0.04869  
4 23 49 39.21 -28 56 30.1 16.53 0.04731  
5 23 49 44.29 -29 16 23.6 19.05 0.05044  
6 23 49 52.57 -28 49 41.2 18.51 0.04989  
7 23 50 13.62 -29 00 32.3 14.31 0.04973 VLG 109
8 23 50 15.62 -29 08 09.2 15.08 0.05062  
9 23 50 16.65 -28 59 50.2 18.88 0.05058  
10 23 50 26.60 -29 06 16.6 18.71 0.04857  
11 23 50 34.41 -29 02 03.2 17.16 0.04920  
12 23 50 36.89 -29 06 58.4 16.80 0.04977  
13 23 50 43.89 -28 57 24.8 16.11 0.04778  



Copyright ESO 2003