A&A 381, 761-770 (2002)
DOI: 10.1051/0004-6361:20011568

Environmental effects in galaxies

The data[*],[*]

D. F. de Mello1 - M. A. G. Maia2 - T. Wiklind1


1 - Onsala Space Observatory, 43992 Onsala, Sweden
2 - Observatório Nacional, Rua Gal. José Cristino 77, RJ 20921, Brazil

Received 5 January 2001 / Accepted 15 October 2001

Abstract
We present optical and millimetric data for 47 intermediate Hubble type spiral galaxies located either in dense environments or in the field. We compare correlations between global parameters, such as far-infrared luminosity, blue luminosity, and total molecular gas content, with other samples of galaxies, including normal galaxies, clusters and ultraluminous infrared galaxies. We find that overall our sample is a well-defined subset of these other samples of galaxies.

Key words: galaxies: interactions - general - stellar content


1 Introduction

A longstanding issue in galaxy evolution is whether galaxies evolve according to a given set of initial conditions or whether the environment in which they reside is decisive for their evolution; i.e. whether galaxy evolution depends on nature or nurture. In order to search for environmental effects in galaxy properties, we have obtained optical and millimetric data for galaxies in dense regions of the Southern sky and in the field. In de Mello et al. (2002, hereafter Paper II) we present an extensive analysis of the data. The main results we found are: intermediate type spirals in dense environments have on average less molecular gas per blue luminosity, lower current SFR, the same SFE and higher atomic gas fraction when compared with field galaxies. Although none of the above results stand out as a single strong diagnostic, given their statistical significance (see Table 3 of Paper II), taken together they suggest a trend for diminished gas content and star formation activity in galaxies in high density environments. We also found that SFR per blue luminosity increases linearly as the total amount of gas increases in LINERs. This result, based on a small sample, suggests that LINERs are powered by star formation rather than an AGN. We refer the reader to Paper II for a more detailed analysis of these results.

In this paper we present the optical and millimetric data; it is organized as follows. Section 2 describes the sample, Sect. 3 describes the optical data, Sect. 4 describes the millimetric data, Sect. 5 describes general properties, and a comparison with other samples, Sect. 6 presents a summary and conclusions. A database of optical and millimetric spectra together with digitized images are shown in Appendix A (only available in electronic form).

2 Sample selection

2.1 Previous samples

Surveys of the molecular gas content in galaxies have in general been done on samples which are far-infrared selected, or galaxies selected exclusively for belonging to clusters or groups (often with a far-infrared selection criteria on top; e.g. Casoli et al. 1991; Combes et al. 1994; Leon et al. 1998). A few exceptions exist in the literature. For example, Sage (1993) presents the CO content of a distance limited sample of 65 non-strongly interacting spiral galaxies, and Horellou et al. (1995) present a CO and HI survey of spiral and lenticular galaxies in the Fornax cluster, both based on samples selected without a far-infrared criterion.

However, until now no survey of galaxies in different environments has included a rigorously selected control sample. For instance, the sample by Casoli et al. (1998) which contains a large sample of 582 objects is an important source of information concerning molecular gas in spiral galaxies. However, it was built by gathering data from various surveys and is very heterogeneous in terms of morphology and environment. It contains galaxies from several clusters as well as galaxies in the field.

2.2 Dense environment and Control Sample (HDS and CS)

In view of these biases plagueing existing samples we have selected our sample from the catalog by Maia et al. (1994) which contains objects in low and high density areas of the Southern sky. The selection of groups adopted by Maia et al. is similar to the methodology developed by Huchra & Geller (1982) with the adaptations described by Maia et al. (1989). The catalog was drawn from the ESO/Uppsala Survey of the ESO(B) Atlas (Lauberts 1982) and used velocity information from the Southern Sky Redshift Survey (e.g., da Costa et al. 1989). The groups are defined to be formed by the accumulation of galaxy pairs with a member in common.

2.3 HDS versus compact groups and poor groups

Although a group-finding algorithm was used to generate the samples, the idea is not to identify groups (either loose or compact), but galaxies in high and low local density environments. The main difference between the HDS and compact groups of galaxies is the isolation criterion which is imposed by the groups selection (Hickson 1982; Coziol et al. 2000). The only 2 compact groups (HCG 21 and HCG 90) in the region searched by Maia et al. (1994) ( $b^{\rm II}\le{-}30^{\circ}$, $\delta <-17\hbox{$.\!\!^\circ$ }5$) have 3 galaxies of each group taking part of the HDS, but none of them take part in the present subsample analysis.

The HDS should also not be confused with poor groups which are defined as systems with less than five bright galaxies but which can have 20-50 faint members (e.g., Zabludoff & Mulchaey 1998; Willmer et al. 1999). Some galaxies in these poor groups are certainly part of the HDS, but since our selection includes only members with known redshift, the HDS will have only the brighter members which have measured redshift. The HDS and CS contain in total 151 and 179 galaxies, respectively.

2.4 Our subsample: Morphology selection

Maia et al. (1994) have analysed the morphology distribution of the HDS and CS and concluded that the HDS has an excess of early-type galaxies compared to the CS. This is interpreted as an effect of the morphology-density relationship (Dressler 1980); i.e. a correlation between morphological types and local density showing that the fraction of early-type galaxies increases as a function of local galaxy density while the fraction of later types decreases (see also Sanroma & Salvador-Solé 1990; Whitmore & Gilmore 1991). Since there are galaxies of all morphologies in the HDS and in the CS, the main goal of our work is to evaluate the effects of the environment in galaxies of the same morphological type when compared with isolated galaxies. The ideal survey would include all galaxies in the HDS and CS, however, due to large size of the samples we have imposed such a selection which is fundamental in order to avoid any bias due to the well-known correlation between morphology and physical properties of galaxies. Figures 2-4 of Roberts & Haynes (1994) summarize clearly how morphology is correlated with fundamental properties of galaxies such as, blue luminosity, far infrared lumninosity, total mass, and neutral hydrogen mass. One of their conclusions is that, although the scatter is large, Sa-Sc have near constant molecular gas normalized either by the blue luminosity or by the total mass. They also pointed out that later-type spirals have less molecular gas and suggest that this could also be due to the CO to H2 conversion factor which would depend on morphology. Therefore, in order to have an homogeneous sample, we selected mostly intermediate spiral galaxies; i.e. Sb, Sbc, and Sc, avoiding Sa and Sd galaxies. In this work we present the analysis of the optical and millimetric data of a subsample of 47 spiral galaxies, 22 in the HDS and 25 in the CS, with velocities less than 5500 km s-1.

Table 1 lists information taken from the NASA/IPAC Extragalactic Database (NED) on each galaxy as follows. Column 1: designation in the ESO-Uppsala catalog (LV89); Col. 2: designation in other catalogs; Col. 3: right ascension ( $^{\rm h\ m\ s}$) and declination ($^{\circ}$ ' '') for J2000; Col. 4: type of sample (control $\rm sample=CS$ and high density $\rm sample=HDS$) and morphological type (Lauberts & Valentijn 1989, hereafter LV89) $\rm 1=Sa$, $\rm 2=Sa$-b, $\rm 3=Sb$, $\rm 4=Sb$-c, $\rm 5=S$..., $\rm 6=Sc$, Sc-d, $\rm 7=S$../Irr, $\rm 8=Sd$; Col. 5: morphological type from The Third Reference Catalogue of Bright Galaxies (RC3; de Vaucouleurs et al. 1991); Col. 6: number of galaxies in the same group (Maia et al. 1989); Col. 7: mean pairwise separation in Mpc (Maia et al. 1989); Col. 8: $B_{\rm T}$ magnitude from RC3; Col. 9: IRAS 60 $\mu$m flux in Jy (Moshir et al. 1990), and Col. 10: IRAS 100 $\mu$m flux in Jy (Moshir et al. 1990).

 
 
Table 1: Observed sample.

ESO-LV		 Other Coord. Sample & Morph. $N_{\rm g}$ $r_{\rm p}$ $B_{\rm T}$ $F_{\rm 60\,\mu m}$ $F_{\rm 100\,\mu m}$
Name Name J2000 Morph. RC3   Mpc   Jy Jy
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

5390050		   00 17 10.1 -19 18 00 CS 5 SAB(rs)c?     13.53 0.977 2.972
3500140 N101 00 23 54.6 -32 32 09 CS 6 SAB(rs)c     13.37 0.549 1.754
3520530 N491 01 21 20.3 -34 03 48 HDS 3 SB(rs)b: 3 0.18 13.21 2.843 8.632
2960380   01 32 27.4 -38 40 40 CS 4 SAB(rs)c     13.99 0.516 1.779
4780060   02 09 19.1 -23 24 54 CS 4 Sbc     13.22 3.543 9.112
5450100 N907 02 23 01.7 -20 42 43 HDS 5 SBdm? sp 5 0.40 13.21 2.649 5.625
5450110 N908 02 23 04.8 -21 14 03 HDS 5 SA(s)c     10.83 14.770 43.670
3550260   02 32 17.5 -35 01 50 CS 4 SB(s)bc:     13.80 0.482 1.588
3550300   02 37 36.4 -32 55 28 CS 4 SB(rs:)bc:     13.59 0.881 3.137
0310050   02 58 06.0 -74 27 24 CS 3.5 SAB(rs)bc     14.07 1.043 3.887
3570190 N1310 03 21 03.7 -37 05 58 HDS 5 SB(rs)cd 55 0.82 12.55 0.881 3.345
5480070 N1325 03 24 25.6 -21 32 35 HDS 3.5 SA(s)bc 7 0.94 12.22 0.631 3.211
5480310 N1353 03 32 03.0 -20 49 04 HDS 3 SA(rs)bc 7 0.94 12.40 2.420 8.786
5480380 I1953 03 33 41.7 -21 28 45 HDS 6 SB(rs)d 7 0.94 12.24 8.470 11.128
4190030   03 42 11.2 -27 51 47 CS 4 (R')SAB(rs)c     13.60 1.334 3.361
4820430 N1459 03 46 58.0 -25 31 11 CS 4 SB(s)bc?     13.62 0.572 2.657
4200030   04 07 45.8 -29 51 30 CS 5 SA(rs)bc     13.52 0.704 2.172
2010220   04 08 59.3 -48 43 42 CS 5 Sbc     14.73 0.356 1.466
1570050 N1536 04 10 59.9 -56 28 48 HDS 5.5 SB(s)c pec: 46 1.30 13.15 0.475 1.649
4840250 N1591 04 29 30.7 -26 42 44 CS 2 SB(r)ab pec     13.77 1.929 5.001
1190060 N1688 04 48 23.8 -59 47 59 HDS 7.5 SB(rs)dm 14 0.85 12.57 2.683 6.677
1190190 N1703 04 52 51.9 -59 44 33 HDS 5 SA(s)c 14 0.85 11.90 2.122 7.723
3050140   05 12 34.1 -39 51 36 CS 5 SB(s)c     14.13 0.378 0.982
2030180 N1803 05 05 26.6 -49 34 05 CS 4 Sbc:     13.38 0.277 0.715
1420500 I4901 19 54 23.1 -58 42 50 CS 5 SAB(r)c     12.29 1.778 6.518
2340160   20 23 25.1 -50 32 43 HDS 5 SAB(s)bc pec 4 0.68 14.56 3.069 7.875
2850080 N6902 20 24 27.7 -43 39 09 HDS 4 SA(r)b 4 0.31 11.64 0.826 3.924
1060120 I5038 20 46 51.2 -65 01 00 CS 6 (R':)SB(s)bc     14.13 0.723 2.460
2350550   21 05 55.4 -48 12 23 HDS 5 (R')SAB(rs)bc 9 1.00 12.70 0.461 2.840
2350570   21 06 21.8 -48 10 14 HDS 4 Sbc: sp 9 1.00 14.45 0.461 3.368
2860820   21 15 45.4 -42 25 33 HDS 5 SAB(s)c 3 0.20 14.51 0.337 1.032
2370020 N7124 21 48 05.7 -50 33 51 CS 4.5 SB(rs)c     13.10 0.791 3.411
1890070 N7140 21 52 15.3 -55 34 10 CS 4 (R'2)SB(rs)b     12.20 2.183 5.886
2880260 N7162 21 59 39.0 -43 18 12 HDS 5 (R')SA(r)bc 4 0.20 13.29 0.484 1.656
5320090 N7167 22 00 30.9 -24 38 00 CS 5 SB(s)c:     13.22 1.314 3.588
6010040   22 01 30.4 -22 04 15 CS 4.6 SB(s)c:     14.58 0.227 0.877
1080130 N7191 22 06 51.3 -64 38 03 HDS 3.5 SAB(rs)c 5 0.48 13.80 0.570 2.061
1080200 I5176 22 11 55.0 -66 50 46 CS 3.9 SAB(s)bc?sp     13.54 3.031 11.21
1460090 N7205 22 08 34.4 -57 26 33 CS 5 SA(s)bc     11.55 8.861 25.960
4050180 N7267 22 24 21.6 -33 41 38 CS 1 (R'1)SB(rs)a     12.91 2.081 4.930
4060250 N7418 22 56 36.0 -37 01 47 HDS 5 SAB(rs)cd 32 1.31 11.66 4.344 15.010
4060330 I5270 22 57 54.7 -35 51 30 HDS 6 SB(rs)c 32 1.31 13.00 3.076 8.398
4070140   23 17 39.7 -34 47 24 CS 5 SB(s)c?     13.48 0.987 2.766
3470340 N7599 23 19 21.1 -42 15 20 HDS 3 SB(s)c 32 1.31 12.08 5.408 21.750
2400110   23 37 49.7 -47 43 42 HDS 4.8 Sb 3 0.18 13.20 0.956 5.612
2400130   23 39 26.9 -47 46 27 HDS 3 (R'1)SAB(rs)b 3 0.18 13.99 0.791 3.411
4710200 N7755 23 45 51.8 -30 31 19 CS 4.5 SB(r)bc     12.56 2.686 8.538


Column 4: $\rm CS=control$ sample, $\rm HDS=high$ density sample; morphological types are: $\rm 1=Sa$, $\rm 2=Sa$-b, $\rm 3=Sb$, $\rm 4=Sb$-c, $\rm 5=S$..., $\rm 6=Sc$, Sc-d, $\rm 7=S$../Irr, $\rm 8=Sd$. Column 6: $N_{\rm g}$ is the number of companions from Maia et al. (1989). Column 7: $r_{\rm p}$ is the mean pairwise separation from Maia et al. (1989).


3 The optical data


 
 
Table 2: Parameters of strong emission lines.

ESO-LV		 Sample & F(H$\beta$)$\times$10-15 F([OIII]5007)$\times$10-15 F(H$\alpha$)$\times$10-15 F([NII]6583)$\times$10-15 EW(H$\alpha$) Type of
name Morph. ergs cm-2 s-1 ergs cm-2 s-1 ergs cm-2 s-1 ergs cm-2 s-1 Å Activity
(1) (2) (3) (4) (5) (6) (7) $^{\dagger}$ (8)

0310050		 CS 3.5 4.0 0.3 15.0 8.2 8.2 HII
1060120 CS 6 10.2 1.5 38.0 18.0 12.4 HII
1080130 HDS 3.5 7.2 0.6 41.0 15.0 14.2 HII
1190190 HDS 5 5.7 1.3 12.0 6.7 5.5 HII
1420500 CS 5 10.0 2.8 20.0 16.0 3.0 L
1460090 CS 5 21.0 5.1 60.0 31.0 5.6 HII
1570050 HDS 5.5 14.5 4.4 53.0 17.0 27.9 HII
2010220 CS 5 12.0 8.8 45.8 13.1 16.6 HII
2030180 CS 4 45.4 23.3 160 63.0 29.2 HII
2340160 HDS 5 11.6 8.0 40.0 15.0 29.6 HII
2350550 HDS 5 3.0 2.4 8.7 17.0   L
2350570 HDS 4 2.1 2.7 5.9 11.0 1.2 L
2370020 CS 4.5 7.9 2.8 3.3 9.5 0.9 L
2400110 HDS 4.8 12.0 0.9 16.6 18.5 1.9 L
2850080 HDS 4 14.6 4.2 9.0 17.0 1.1 L
2860820 HDS 5 8.0 0.9 27.0 11.0 14.6 HII
2880260 HDS 5 19.0 1.0 49.0 32.0 6.6 L
2960380 CS 4 7.2 1.7 26.0 10.0 16.5 HII
3050140 CS 5 1.8 0.4 6.7 3.8 8.7 HII
3500140 CS 6 8.7 2.6 33.0 14.0 13.3 HII
3550300 CS 4 12.2 2.6 22.2 18.0 3.7 L
3570190 HDS 5 13.4 8.4 50.0 22.0 14.9 HII
4060330 HDS 6 43.0 21.0 180 66.0 27.4 HII
4070140 CS 5 53.2 51.0 190 58.0 40.6 HII
4190030 CS 4 5.1 1.6 22.0 7.8 24.2 HII
4200030 CS 5 15.2 4.7 48.0 18.0 13.3 HII
4710200 CS 4.5 24.3 6.5 98.0 47.0 10.3 HII
4780060 CS 4 23.1 6.0 63.0 26.0 13.7 HII
4820430 CS 4 6.9 2.6 17.0 9.4 6.7 HII
5320090 CS 5 16.8 7.3 51.0 21.0 13.4 HII
5390050 CS 5 16.7 9.2 64.0 28.0 20.0 HII
5450100 HDS 5 23.4 24.7 95.0 26.0 30.0 HII
5480310 HDS 3 16.0 1.0 53.0 35.0 4.2 L
5480380 HDS 6 5.6 1.4 24.0 9.6 28.8 HII
6010040 CS 4.6 8.6 1.0 30.0 14.0 6.6 HII


Column 2: $\rm CS=control$ sample, $\rm HDS=high$ density sample; morphological types are: $\rm 1=Sa$, $\rm 2=Sa$-b, $\rm 3=Sb$, $\rm 4=Sb$-c, $\rm 5=S$..., $\rm 6=Sc$, $\rm Sc$-d, $\rm 7=S$../Irr, 8=Sd. Column 8: $\rm HII=activity$ typical of HII regions, $\rm L=activity$ typical of LINERs.
$^{\dagger}$ Only EW(H$\alpha$) is corrected for internal reddening.



  \begin{figure*} \centering \includegraphics[angle=-90,width=16.5cm,clip]{MS1011f1.ps}\end{figure*} Figure 1: Left panel a): total molecular gas as a function of FIR luminosity. The CS is marked by open squares and HDS by filled circles. Right panel b): the same as in the left panel. Ultraluminous infrared galaxies (Sanders et al. 1991) are marked by open diamonds, normal spiral galaxies from Young et al. (1989) and Braine et al. (1993) are marked by dots, cluster galaxies (Coma and Fornax) from Casoli et al. (1991) and Horellou et al. (1995) are marked by open stars. Luminosity is in $L_{\odot}$ and mass is in $M_{\odot}$.
Open with DEXTER

Long-slit spectra were obtained with the Boller & Chivens Cassegrain spectrograph at the ESO 1.52 m telescope (La Silla) during several runs in 1997 and 1998 as part of a key project during Brazilian time. We used the Loral/Lesser CCD (No. 39) with $2048 \times 2048$ pixels ( $\rm 1~pixel = 15~\mu$m) and grating No. 27 which has 600 lines mm-1 and gives a spectral coverage of 3600-7500 Å and dispersion of 1.7 Å pix-1. The slit width was 3'' and positioned along the major axis of the galaxies which corresponds to galactic sizes of 250 pc for the closest galaxy in the sample and to 1 kpc for the most distant galaxy in the sample.

Spectrophotometric standard stars were observed close to zenith several times during the night with a slit width of 5''. A He-Ar lamp was observed after every exposure and used for wavelength calibration. Typical exposure times were $2 \times 20{-}30$ min for galaxies and 5-10 min for stars.

Standard data reduction, including bias and flat-field correction, was performed using IRAF. One dimensional spectra were extracted from each galaxy integrated along the slit length. We corrected for Galactic extinction using the Cardelli et al. (1989) extinction curve and E(B-V) from NED. All spectra are flux calibrated and corrected for Doppler shift which was calculated using a cross-correlation technique.

Starlight subtraction was particularly critical in weak lines such as H$\beta$. The starlight contribution was removed using the technique of McCall et al. (1985, see also Storchi-Bergmann et al. 1994). Taking into account that in the typical stellar population the equivalent width of H$\beta$ in absorption is of the order of 1.5 Å, we corrected for this effect by adding a factor of 1.5 times the continuum flux around H$\beta$ to the emission line flux. When no emission line was clearly visible we adopted a theoretical ratio, H$\alpha$/H $\beta=2.86$ (Ho et al. 1997). In this case, the value of H$\beta$ is an upper limit. Therefore, higher ratios of H$\alpha$/H$\beta$ can also be expected. We have investigated whether a higher ratio would influence our results by adopting ratios typical of AGNs (H$\alpha$/H$\beta=3.1$). We found no significant difference given the uncertainties in the continuum determination.

We tested a second method of starlight subtraction using templates of old stellar populations from Bica (1988). We subtracted our spectra from the templates and then measured the fluxes. Both methods gave similar results given the accuracy of the measurements, dominated by the uncertainty in the continuum determination (Cid Fernandes et al. 1998).

We measured the integrated fluxes and equivalent widths of the emission lines H$\beta$, [OIII]$\lambda$5007, [NII]$\lambda$6548, H$\alpha$, [NII]$\lambda$6583, [SII]$\lambda$6716,6731 for 35 galaxies with good signal-to-noise spectra. Internal reddening was estimated from the Cardelli et al. (1989) extinction curve and H$\alpha$/H$\beta$ ratios. H$\alpha$ equivalent width was measured after internal reddening correction, following the same procedure as in Ho et al. (1997).

The type of activity was classified by measuring line-intensity ratios (log([OIII] $\lambda$ 5007/H$\beta$) and log([NII] $\lambda$ 6583/H$\alpha$)) and applying standard diagnostic diagrams (Baldwin et al. 1981; Veilleux & Osterbrock 1987). In Paper II we show the diagnostic diagram used to classify the type of activity.

Table 2 lists the emission line parameters as follows. Column 1: designation in the ESO-Uppsala catalog (LV89); Col. 2: type of sample (control $\rm sample=CS$ and high density $\rm sample=HDS$) and morphological type (LV89) $\rm 1=Sa$, $\rm 2=Sa$-b, $\rm 3=Sb$, $\rm 4=Sb$-c, $\rm 5=S$..., $\rm 6=Sc$, Sc-d, $\rm 7=S$../Irr, $\rm 8=Sd$; Col. 3: H$\beta$ flux; Col. 4: [OIII]$\lambda$5007 flux; Col. 5: H$\alpha$ flux; Col. 6: [NII]$\lambda$6583 flux; Col. 7: H$\alpha$equivalent width in Å, and Col. 8: type of activity ( $\rm L=LINERS$, $\rm HII=HII$ region).

In Appendix A (only available in electronic form) we show the optical spectra of 35 galaxies of our sample. We also included in the Appendix the CO spectra described below and images from The Digitized Sky Surveys[*] which allows direct inspection of the galaxies morphology.

 
 
Table 3: CO data.

ESO-LV		 Sample & $V_{\rm CO}$ $\Delta V_{\rm CO}$ log $L_{\rm B}$ $L_{\rm FIR}$$\times$109 $I_{\rm CO(1-0)}$ $M_{\rm H_2}$$\times$109 $I_{\rm CO(2-1)}$
name Morph. kms-1 kms-1 $L_{\odot}$ $L_{\odot}$ K kms-1 $M_{\odot}$ K kms-1
(1) (2) (3) (4) (5) (6) (7) (8)  

0310050		 CS 3.5 4714 287 10.11 13.60 $\pm$ 0.39 3.62 $\pm$ 0.26 3.30 $\pm$ 0.23 3.64 $\pm$ 0.22
1060120 CS 6 4154 180 9.97 6.90 $\pm$ 0.39 2.75 $\pm$ 0.28 1.93 $\pm$ 0.19  
1080130 HDS 3.5 2941 135 9.78 2.67 $\pm$ 0.15 2.43 $\pm$ 0.21 0.81 $\pm$ 0.07  
1080200 CS 3.9 1720 183 9.37 4.45 $\pm$ 0.20 6.28 $\pm$ 0.25 0.65 $\pm$ 0.03 3.63 $\pm$ 0.18
1190060 HDS 7.5 1256 43 9.48 1.66 $\pm$ 0.05 1.99 $\pm$ 0.14 0.11 $\pm$ 0.01  
1190190 HDS 5 1527 33 9.94 2.52 $\pm$ 0.07 5.06 $\pm$ 0.19 0.42 $\pm$ 0.02  
1420500 CS 5 2135 165 10.10 4.40 $\pm$ 0.09 3.40 $\pm$ 0.25 0.59 $\pm$ 0.04  
1460090 CS 5 1652 183 10.13 10.40 $\pm$ 0.34 11.68 $\pm$ 0.66 1.10 $\pm$ 0.06  
1570050 HDS 5.5 1311 40 9.30 0.39 $\pm$ 0.02 1.66 $\pm$ 0.06 0.10 $\pm$ 0.01 0.88 $\pm$ 0.09
1890070 CS 4.0 3006 169 10.44 9.15 $\pm$ 0.36 4.22 $\pm$ 0.26 1.48 $\pm$ 0.09  
2010220 CS 5 3990 188 9.70 3.53 $\pm$ 0.23 1.50 $\pm$ 0.11 0.98 $\pm$ 0.07 1.30 $\pm$ 0.11
2030180 CS 4 4123 157 10.27 25.39 $\pm$ 1.17 4.66 $\pm$ 0.23 3.30 $\pm$ 0.16 5.04 $\pm$ 0.14
2340160 HDS 5 5218 10 10.01 3.72 $\pm$ 0.50 0.82 $\pm$ 0.05 0.94 $\pm$ 0.06 0.45 $\pm$ 0.12
2350550 HDS 5 5098 70 10.73 9.92 $\pm$ 1.11 1.88 $\pm$ 0.11 2.04 $\pm$ 0.12 1.34 $\pm$ 0.11
2350570 HDS 4 5069 248 10.03 11.08 $\pm$ 1.30 3.22 $\pm$ 0.12 3.45 $\pm$ 0.13 3.56 $\pm$ 0.22
2370020 CS 4.5 5214 236 10.58 13.72 $\pm$ 0.70 4.42 $\pm$ 0.16 4.90 $\pm$ 0.18 1.96 $\pm$ 0.11
2400110 HDS 4.8 2890 278 10.00 5.81 $\pm$ 0.31 5.20 $\pm$ 0.17 1.65 $\pm$ 0.05  
2400130 HDS 3 3284 50 9.80 5.17 $\pm$ 0.31 2.58 $\pm$ 0.15 1.08 $\pm$ 0.06  
2850080 HDS 4 2838 132 10.63 4.45 $\pm$ 0.23 1.97 $\pm$ 0.21 0.64 $\pm$ 0.07  
2860820 HDS 5 4958 134 9.98 4.42 $\pm$ 0.51 1.62 $\pm$ 0.09 1.66 $\pm$ 0.09 1.68 $\pm$ 0.08
2880260 HDS 5 2383 80 9.79 1.42 $\pm$ 0.10 1.51 $\pm$ 0.11 0.32 $\pm$ 0.02  
2960380 CS 4 3645 51 9.90 3.73 $\pm$ 0.33 0.84 $\pm$ 0.12 0.44 $\pm$ 0.06  
3050140 CS 5 4761 450 10.11 4.31 $\pm$ 0.55 2.38 $\pm$ 0.10 2.31 $\pm$ 0.10 1.21 $\pm$ 0.08
3470340 HDS 3 1671 117 9.92 7.85 $\pm$ 0.79 23.46$^{\dagger}$ $\pm$ 0.62 2.27 $\pm$ 0.06  
3500140 CS 6 3400 35 10.09 3.30 $\pm$ 0.25 2.68 $\pm$ 0.09 1.23 $\pm$ 0.04  
3520530 HDS 3 3874 260 10.27 21.89 $\pm$ 0.93 10.85 $\pm$ 0.52 6.55 $\pm$ 0.32  
3550260 CS 4 1985 105 9.42 0.95 $\pm$ 0.07 1.02 $\pm$ 0.13 0.15 $\pm$ 0.02  
3550300 CS 4 4448 336 10.25 10.05 $\pm$ 0.43 4.08 $\pm$ 0.44 3.33 $\pm$ 0.36  
3570190 HDS 5 1789 66 9.83 1.52 $\pm$ 0.06 3.40 $\pm$ 0.28 0.41 $\pm$ 0.03  
4050180 CS 1 3375 124 10.27 10.67 $\pm$ 0.68 7.70 $\pm$ 0.37 3.52 $\pm$ 0.17  
4060250 HDS 5 1470 83 9.98 4.42 $\pm$ 0.20 27.44$^\ddagger$ $\pm$ 0.74 2.04 $\pm$ 0.05  
4060330 HDS 6 1922 110 9.71 5.01 $\pm$ 0.21 3.15 $\pm$ 0.17 0.42 $\pm$ 0.02  
4070140 CS 5 2761 129 9.85 3.54 $\pm$ 0.23 2.64 $\pm$ 0.14 0.78 $\pm$ 0.04  
4190030 CS 4 4146 83 10.20 11.19 $\pm$ 0.36 1.52 $\pm$ 0.13 1.10 $\pm$ 0.09  
4200030 CS 5 4093 163 10.22 6.41 $\pm$ 0.41 2.86 $\pm$ 0.20 2.02 $\pm$ 0.14  
4710200 CS 4.5 3017 160 10.30 12.49 $\pm$ 0.53 5.46 $\pm$ 0.36 1.95 $\pm$ 0.13  
4780060 CS 4 5401 164 10.58 51.12 $\pm$ 2.91 8.79 $\pm$ 0.37 10.86 $\pm$ 0.46 15.16 $\pm$ 0.33
4820430 CS 4 4073 85 10.17 6.57 $\pm$ 0.33 3.36 $\pm$ 0.30 2.35 $\pm$ 0.21  
4840250 CS 2 4128 191 10.13 16.54 $\pm$ 0.64 3.63 $\pm$ 0.31 2.65 $\pm$ 0.22  
5320090 CS 5 2582 83 9.91 4.22 $\pm$ 0.20 1.54 $\pm$ 0.17 0.41 $\pm$ 0.05  
5390050 CS 5 3158 256 9.98 5.03 $\pm$ 0.29 4.95 $\pm$ 0.33 1.99 $\pm$ 0.13  
5450100 HDS 5 1715 21 9.55 3.21 $\pm$ 0.14 1.29 $\pm$ 0.09 0.15 $\pm$ 0.01 2.67 $\pm$ 0.13
5450110 HDS 5 1456 168 10.35 14.78 $\pm$ 0.72 27.01 $\pm$ 0.92 2.15 $\pm$ 0.07  
5480070 HDS 3.5 1557 17 9.87 1.05 $\pm$ 0.05 1.79 $\pm$ 0.11 0.17 $\pm$ 0.01  
5480310 HDS 3 1531 108 9.79 3.17 $\pm$ 0.13 6.99 $\pm$ 0.32 0.65 $\pm$ 0.03  
5480380 HDS 6 1874 86 10.03 10.56 $\pm$ 0.31 2.14 $\pm$ 0.15 0.30 $\pm$ 0.02  
6010040 CS 4.6 5219 103 10.01 3.85 $\pm$ 0.56 1.01 $\pm$ 0.08 1.17 $\pm$ 0.09 0.78 $\pm$ 0.04


$^{\dagger}$ added CO(1-0) intensities of 5 points (map);
$^\ddagger$ added CO(1-0) intenstities of 7 points (map).
Column 2: CS=control sample, $\rm HDS=high$ density sample; morphological types are: $\rm 1=Sa$,
$\rm 2=Sa$-b, $\rm 3=Sb$, $\rm 4=Sb$-c, $\rm 5=S$..., $\rm 6=Sc$, Sc-d, $\rm 7=S$../Irr, $\rm 8=Sd$.


4 The CO data


  \begin{figure*} \centering \includegraphics[angle=-90,width=16.5cm,clip]{MS1011f2.ps}\end{figure*} Figure 2: Left panel a): total molecular gas as a function of blue luminosity. Right panel b): the same as in the left panel. Additional samples of ultraluminous infrared galaxies, galaxies in clusters, and spiral galaxies are included. Symbols are the same as in Fig. 1. Luminosity is in $L_{\odot}$ and mass is in $M_{\odot}$.
Open with DEXTER

Millimetric observations were carried out at the Swedish-ESO (SEST) 15 m radiotelescope at La Silla in October 1996 and September 1998 during good weather conditions. In the first run we used the SESIS 100 receiver with a 1 GHz bandwidth at 115 GHz (12CO(1-0)). Typical system temperatures were $\sim$250 K (in the $T_{\rm A}^{*}$ scale) at the elevation of the sources and typical zenith opacities between 0.1-0.2. During the second run we used the IRAM 115 and IRAM 230 receivers with 500 MHz and 1 GHz bandwith, at 115 GHz (12CO(1-0)) and 230 GHz (12CO(2-1)), respectively. The half power beamwidth of the SEST at 115 GHz is 45'' and 23'' at 230 GHz.

All galaxies were observed at the central optical coordinate. Integration times were 2-3 hours depending on the signal-to-noise achieved. The pointing was regularly checked on nearby SiO masers. The pointing uncertainties were of the order of 5''. CO emission was detected in 47 galaxies and had low signal-to-noise detection in only 5 galaxies, ESO-LV1080110 (HDS), ESO-LV1880170 (CS), ESO-LV2850050 (HDS), ESO-LV3550300 (CS), and ESO-LV6050070 (CS). We have not included these galaxies in our analysis.

Two galaxies, ESO-LV3470340 and ESO-LV4060250, were considerably larger than the SEST beam and were observed in 5 and 7 positions, respectively, spaced by half of a beamwidth (23''). In Appendix A we show each position along the major axis of the galaxy and give their spectra. We have added the intensities at each position in order to obtain the total CO intensity of each galaxy.

The CO spectra were reduced with the CLASS package (Forveille et al. 1990). We have binned the spectra with a boxcar function. Spectra were corrected for first order baseline in most of the cases or third order in a few obvious cases where first order did not give a good fit to the data. CO intensities were calculated by using the main-beam efficiency, $\eta_{\rm mb}$, values of 0.7 and 0.5 for 115 GHz and 230 GHz, respectively. We estimated the 1 $\sigma$ uncertainty in the integrated line intensity taking into account the channel-to-channel noise (rms), the width of the emission profile ($\Delta V$) and the number of channels (N) that the emission profile covers ( ${\rm error = rms}\times\Delta V\times N^{-1/2}$).

Table 3 lists the CO data as follows. Column 1: designation in the ESO-Uppsala catalog (LV89); Col. 2: type of sample (control $\rm sample=CS$ and high density $\rm sample=HDS$) and morphological type (LV89) $\rm 1=Sa$, $\rm 2=Sa$-b, $\rm 3=Sb$, $\rm 4=Sb$-c, $\rm 5=S$..., $\rm 6=Sc$, Sc-d, $\rm 7=S$../Irr, $\rm 8=Sd$; Col. 3: velocity derived from central CO(1-0) profiles in kms-1; Col. 4: the width of the emission profile in kms-1; Col. 5: blue luminosity in $L_{\odot}$ derived from $B_{\rm T}$ magnitude (errors in $L_{\rm B}$ are within 10% when the magnitude estimates in the RC3 have errors of 0.1 mag); Col. 6: far-infrared luminosity in $L_{\odot}$ calculated as described in the next section; Col. 7: CO intensity in the line J=(1-0) in K kms-1 and errors; Col. 8: H$_{\rm 2}$ masses and errors in $M_{\odot}$ estimated from the velocity integrated CO(1-0) emission as described in the next section, and Col. 9: CO intensity in the line J=(2-1) in K kms-1. Distances were corrected for the Virgocentric flow according to model 3.1 in Aaronson et al. (1982). Hubble constant value of 75 kms-1 Mpc-1 was adopted in all calculations.

Table 4 lists the CO intensity in the line J=(1-0) available in the literature for 7 galaxies (4 in the HDS and 3 in the CS). The differences between the fluxes we have measured and the ones obtained previously are due to (i) different sizes of the beam (Elfhag et al. 1996); (ii) baseline adjustments (Combes et al. 1994; Andreani et al. 1995), or short integration time (Horellou & Booth 1997).

5 General properties


   
Table 4: CO data from the literature.
ESO-LV Sample $I_{\rm CO(1-0)}$ References
name   K kms-1  
1060120 CS 2.2 Combes et al. (1994)$^{\dagger}$
1570050 HDS <1.2 Horellou & Booth (1997)$^{\dagger}$
3570190 HDS <0.6 Horellou & Booth (1997)$^{\dagger}$
4780060 CS $5.4\pm 1.8$ Andreani et al. (1995)$^{\dagger}$
4840250 CS $3.5\pm 0.7$ Andreani et al. (1995)$^{\dagger}$
5450110 HDS $12.2\pm 0.8$ Elfhag et al. (1996)$^\ddagger$
5480380 HDS 4.4 Combes et al. (1994)$^{\dagger}$


$^{\dagger}$ Using SEST; $^\ddagger$ using Onsala 20 m.



 
 
Table 5: Average values.
Sample log $L_{\rm B}$ log $L_{\rm FIR}$ log $M_{\rm H_2}$ EW(H$\alpha$)$^{\dagger}$
  $L_{\odot}$ $L_{\odot}$ $M_{\odot}$ Å
HDS mean 9.94 $\pm$ 0.33 9.59 $\pm$ 0.40 8.86 $\pm$ 0.39 15.9 $\pm$ 11.3
HDS median 9.94 $\pm$ 0.12 9.65 $\pm$ 0.28 8.91 $\pm$ 0.40 14.2 $\pm$ 11.2
CS mean 10.08 $\pm$ 0.29 9.85 $\pm$ 0.35 9.18 $\pm$ 0.39 8.7 $\pm$ 3.4
CS median 10.11 $\pm$ 0.14 9.82 $\pm$ 0.21 9.29 $\pm$ 0.22 8.2 $\pm$ 3.3
$\textstyle \parbox{14cm}{ $^\dagger$\space Without LINERs.}$


  \begin{figure*} \centering \includegraphics[angle=-90,width=16.5cm,clip]{MS1011f3.ps}\end{figure*} Figure 3: Left panel a): total molecular gas normalized by the blue luminosity as a function of blue luminosity. Right panel b): the same as in the left panel. Additional samples of ultraluminous infrared galaxies, galaxies in clusters, and spiral galaxies are included. Symbols are the same as in Fig. 1. Luminosity is in $L_{\odot}$ and mass is in $M_{\odot}$.
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The FIR emission together with the molecular gas provide unique information in terms of fuel and star formation. The FIR luminosity was calculated using the relation (Lonsdale & Helou 1985)

\begin{eqnarray*}L_{\rm FIR} = 5.9\times 10^{5}D^{2}(2.58\times F_{60}+F_{100}) \end{eqnarray*}


where F60 and F100 are fluxes in Jy at 60 and 100 $\mu$m detected by IRAS and D is the distance in Mpc corrected for the Virgo infall.

H$_{\rm 2}$ masses were estimated from the velocity integrated CO(1-0) emission, using a $N_{\rm H_{2}}/I_{\rm CO}$ conversion ratio of $3\times 10^{20}$ cm-2 (K kms-1).

We are assuming that the conversion factor is the same in all galaxies in our sample. This assumption is reasonable since our sample do not contain any later-type systems (Sd, Sm, Ir) which, despite the ongoing star formation, show weak CO emission (e.g. Rubio et al. 1991).

Average and median values of $L_{\rm B}$, $L_{\rm FIR}$, $M_{\rm H_2}$, and H$\alpha$ equivalent width are presented in Table 5.

Figures 1a and 2a show the total amount of molecular gas as a function of FIR and blue luminosities. Figure 1a confirms the known correlation between $L_{\rm FIR}$ and the H$_{\rm 2}$ masses (correlation $\rm coefficient= 0.80$ and 0.84 for the HDS and CS, respectively). From Fig. 2a we verify that galaxies in the CS are on average more luminous than those in the HDS (a distance bias in our subsample). In order to eliminate this effect, CO intensities were normalized by the blue luminosity, $L_{\rm B}$, in the analysis presented in Paper II. Given our morphological selection criteria, we assumed that the mass/$L_{\rm B}$ ratio is approximately the same for our galaxies (Roberts & Haynes 1994) and $L_{\rm B}$ is thus a measure of the total mass.

We have plotted the $M_{\rm H_{2}}/L_{\rm B}$ as a function of $L_{\rm B}$ (Fig. 3a) in order to compare whether the bias in blue luminosity present in our subsample may cause a bias in our analysis. The correlation found for HDS and CS is very similar (correlation $\rm coefficient= -0.03$ and 0.06 for the HDS and CS, respectively) suggesting no evident bias. We have compared our sample properties with samples observed by others, such as normal spiral galaxies (Young et al. 1989; Braine et al. 1993), the ultraluminous FIR galaxies (Sanders et al. 1991), and galaxies in the Coma and Fornax clusters (Casoli et al. 1991; Horellou et al. 1995). As it is shown in Figs. 1b, 2b, and 3b the 47 spiral galaxies of our sample (HDS and CS) have correlations between global parameters which are similar to those in other samples. The ultraluminous FIR galaxies (Sanders & Mirabel 1996), as expected, are overall brighter and more massive than our subsample. The other samples include spirals of all types which explains the large dispersion found in luminosities and masses.

  \begin{figure*} \centering \includegraphics[angle=-90,width=16.5cm,clip]{MS1011f4.ps} % \end{figure*} Figure 4: Left panel a): FIR luminosity normalized by the total molecular gas as a function of the FIR luminosity normalized by the blue luminosity. Right panel b): the same as in the left panel. Additional samples of ultraluminous infrared galaxies, galaxies in clusters, and spiral galaxies are included. Symbols are the same as in Fig. 1. Luminosity is in $L_{\odot}$ and mass is in $M_{\odot}$.
Open with DEXTER

As previously mentioned, only intermediate Hubble types (Sb, Sbc, and Sc) were selected in order to avoid any bias due to the correlation between general properties and morphology. However, even in this sample the uncertainties in morphological classification should be taken into account when making any firm statement. Galaxies in dense environments can have their morphology distorted by tidal effects which makes them difficult to classify. One should refer to Appendix A (only available in electronic form) in order to visually check the morphology of each individual galaxy in more detail. We also refer to the detailed morphological classification taken from RC3 presented in Table 1 which gives a general idea on the complexity of the morphologies.

In Table 3 we give both the CO(1-0) and CO(2-1) integrated line intensitites. In order to estimate the CO(2-1)/CO(1-0) intensity ratios we need to convolve the CO(2-1) data to the same angular resolution as the CO(1-0) data. Since we observed only a single position for most galaxies, we can not do this. However, taking the values in Table 3 at face value, the average CO(1-0) to CO(2-1) line intensity ratio is $0.93\pm 0.47$. This is an upper limit to the line ratio. In the case of a molecular gas distribution more extended than both the CO(1-0) and CO(2-1) telescope beams (45'' and 23'', respectively), the correction for different angular resolutions would be 1.0. In the other extreme, with the CO emission originating in a point source, the correction for different angular resolutions would be 0.25. Since our telescope beam in almost all cases is large with respect to the optical extent of the galaxies, and since the molecular gas is likely to be centrally concentrated, the correction for different angular resolutions should be $\sim$0.5. Our average line ratio is thus ${\sim} 0.5 \pm 0.4$. This value is lower than that found by Braine et al. (1993) of $0.89\pm 0.34$ for normal spiral galaxies. The lower value is characteristic of optically thick and subthermally excited molecular gas and most likely reflects the lower star formation activity in our environmentally selected sample as opposed to far infrared bright selected samples.

In Fig. 4 we verify that the HDS and CS are also very similar to the galaxies in other samples in terms of SFE. We conclude that the intermediate type spirals in the HDS and CS do not belong to a separate class of objects but contain objects with properties similar to galaxies in clusters, nearby spiral galaxies and infrared luminous galaxies.

6 Summary

In this paper we present millimetric and optical data obtained in order to study environmental effects in galaxies. Our sample has 47 intermediate Hubble type spirals in either dense environments or in the field. We compared general properties, such as far-infrared luminosity, blue luminosity, and total molecular gas content, to other samples of galaxies, such as ultraluminous infrared galaxies, clusters of galaxies and spiral galaxies. We find that overall our sample has general properties very similar to these other galaxies; i.e. they are not a separate class of objects.

Acknowledgements
We thank the ON team of observers at the ESO1.52m, in particular Christopher Willmer for helping with the data reduction and Henrique Schmitt for valuable suggestions regarding the stellar contamination. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The Digitized Sky Surveys were produced at the Space Telescope Science Institute under US Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. D.F.M. was partially supported by CNPq Fellowship 301456/95-0, and the Swedish Vetenskapsrådet project number F620-489/2000. M.A.G.M. was supported by CNPq grant 301366/86-1. T.W. was supported by Vetenskapsrådet project number F1299/1999.

References

 

Online Material

Appendix A: The database

The database is composed of:

1.
Optical spectra of 35 galaxies taken with Boller & Chivens Cassegrain spectrograph at the ESO 1.52 m telescope (La Silla). The spectra shown are in restframe wavelength versus Flux, which was normalized to 10 flux units at 5870 Å.

2.
12CO(1-0) spectra of 47 galaxies, and 12CO (2-1) spectra of 14 galaxies taken with the SEST telescope. The spectra shown are in heliocentric velocities (km s-1) versus main beam Temperature ( $T_{\rm mb}$) in mK. Spectra were binned with a boxcar function resulting in a velocity resolution of $\sim$20-30 km s-1. Spectra were corrected for first or, in a few cases, third order baseline.

3.
We have also included images from The Digitized Sky Surveys[*] which allows direct inspection of the morphology of the galaxies. All images are of size 8$' \times$ 8' and centered on the objects. North is to the top and East is to the left. The designation in the ESO-Uppsala catalog (Lauberts & Valentijn 1989) and the type of sample (control sample=CS and high density sample=HDS) are given below each image.


  \begin{figure*}\par\psfig{figure=0310050.ps,width=17.5cm}\end{figure*} Figure A.1: Upper left: ESO-LV 0310050 image from the STScI Digitized Sky Survey (8$' \times$ 8'). North is to the top and East is to the left. Circle on the bottom left corresponds to 45'', the size of the SEST beam at 115GHz (12CO(1-0)). Upper right: Spectrum at 115GHz (12CO (1-0)), intensities are in mK. Bottom left: optical spectrum normalized to 10 flux units at 5870 Å. Bottom right: spectrum at 230 GHz (12CO (2-1)), intensities are in mK.


  \begin{figure*}\par\psfig{figure=1060120.ps,width=17.5cm}\end{figure*} Figure A.2: Upper left: ESO-LV 1060120 image from the STScI Digitized Sky Survey (8$' \times$ 8'). North is to the top and East is to the left. Circle on the bottom left corresponds to 45'', the size of the SEST beam at 115GHz (12CO(1-0)). Upper right: Spectrum at 115GHz (12CO (1-0)), intensities are in mK. Bottom left: optical spectrum normalized to 10 flux units at 5870 Å.


  \begin{figure*}\par\psfig{figure=1080130.ps,width=17.5cm}\end{figure*} Figure A.3: ESO-LV 1080130. Same caption as in Fig. A.2.


  \begin{figure*}\par\psfig{figure=1080200.ps,width=17.5cm}\end{figure*} Figure A.4: Upper left: ESO-LV 1080200 image from the STScI Digitized Sky Survey (8$' \times$ 8'). North is to the top and East is to the left. Circle on the bottom left corresponds to 45'', the size of the SEST beam at 115GHz (12CO(1-0)). Upper right: Spectrum at 115GHz (12CO (1-0)), intensities are in mK. Bottom right: spectrum at 230 GHz (12CO (2-1)), intensities are in mK.


  \begin{figure*}\par\psfig{figure=1190060.ps,width=17.5cm}\end{figure*} Figure A.5: Upper left: ESO-LV 1190060 image from the STScI Digitized Sky Survey (8$' \times$ 8'). North is to the top and East is to the left. Circle on the bottom left corresponds to 45'', the size of the SEST beam at 115GHz (12CO(1-0)). Upper right: Spectrum at 115GHz (12CO (1-0)), intensities are in mK.


  \begin{figure*}\par\psfig{figure=1190190.ps,width=17.5cm}\end{figure*} Figure A.6: ESO-LV 1190190. Same caption as in Fig. A.2.


  \begin{figure*}\par\psfig{figure=1460090.ps,width=17.5cm}\end{figure*} Figure A.7: ESO-LV 1460090. Same caption as in Fig. A.2.


  \begin{figure*}\par\psfig{figure=1570050.ps,width=17.5cm}\end{figure*} Figure A.8: ESO-LV 1570050. Same caption as in Fig. A.1.


  \begin{figure*}\par\psfig{figure=1890070.ps,width=17.5cm}\end{figure*} Figure A.9: ESO-LV 1890070. Same caption as in Fig. A.5.


  \begin{figure*}\par\psfig{figure=2010220.ps,width=17.5cm}\end{figure*} Figure A.10: ESO-LV 2010220. Same caption as in Fig. A.1.


  \begin{figure*}\par\psfig{figure=2030180.ps,width=17.5cm}\end{figure*} Figure A.11: ESO-LV 2030180. Same caption as in Fig. A.1.


  \begin{figure*}\par\psfig{figure=2340160.ps,width=17.5cm}\end{figure*} Figure A.12: ESO-LV 2340160. Same caption as in Fig. A.1.


  \begin{figure*}\par\psfig{figure=2350550.ps,width=17.5cm}\end{figure*} Figure A.13: ESO-LV 2350550. Same caption as in Fig. A.1.


  \begin{figure*}\par\psfig{figure=2350570.ps,width=17.5cm}\end{figure*} Figure A.14: ESO-LV 2350570. Same caption as in Fig. A.1.


  \begin{figure*}\par\psfig{figure=2370020.ps,width=17.5cm}\end{figure*} Figure A.15: ESO-LV 2370020. Same caption as in Fig. A.1.


  \begin{figure*}\par\psfig{figure=2400110.ps,width=17.5cm}\end{figure*} Figure A.16: ESO-LV 2400110. Same caption as in Fig. A.2.


  \begin{figure*}\par\psfig{figure=2400130.ps,width=17.5cm}\end{figure*} Figure A.17: ESO-LV 2400130. Same caption as in Fig. A.5.

Appendix A: The Database - Cont.


  \begin{figure*}\par\setcounter{figure}{17} \psfig{figure=2850080.ps,width=17.5cm}\end{figure*} Figure A.18: ESO-LV 2850080. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=2860820.ps,width=17.5cm}\end{figure*} Figure A.19: ESO-LV 2860820. Same caption as in Fig.A.1.


  \begin{figure*}\par\psfig{figure=2880260.ps,width=17.5cm}\end{figure*} Figure A.20: ESO-LV 2880260. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=2960380.ps,width=17.5cm}\end{figure*} Figure A.21: ESO-LV 2960380. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=3050140.ps,width=17.5cm}\end{figure*} Figure A.22: ESO-LV 3050140. Same caption as in Fig.A.1.


  \begin{figure*}\par\psfig{figure=3470340.ps,width=17.5cm}\end{figure*} Figure A.23: Upper left: ESO-LV 3470340 image from the STScI Digitized Sky Survey (8$' \times$ 8'). North is to the top and East is to the left. Numbers along the major axis corresponds to positions spaced by half of a beamwidth (23''). Circle on the bottom left corresponds to the size of the SEST beam at 115GHz (12CO(1-0)) 45''. Upper and bottom right: spectrum at 115GHz (12CO (1-0)) taken at positions 1 and 2. Intensities are in mK. Bottom left: optical spectrum normalized to 10 flux units.


  \begin{figure*}\par\psfig{figure=3470340.ps,width=17.5cm}\end{figure*} Figure A.24: Upper left: ESO-LV 3470340 image from the STScI Digitized Sky Survey (8$' \times$ 8'). North is to the top and East is to the left. Numbers along the major axis corresponds to positions spaced by half of a beamwidth (23''). Circle on the bottom left corresponds to the size of the SEST beam at 115GHz (12CO(1-0)) 45''. Upper right, bottom left and right: spectrum at 115GHz (12CO (1-0)) taken at position 3, 4 and 5. Intensities are in mK.


  \begin{figure*}\par\psfig{figure=3500140.ps,width=17.5cm}\end{figure*} Figure A.25: ESO-LV 3500140. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=3520530.ps,width=17.5cm}\end{figure*} Figure A.26: ESO-LV 3520530. Same caption as in Fig.A.5.


  \begin{figure*}\par\psfig{figure=3550260.ps,width=17.5cm}\end{figure*} Figure A.27: ESO-LV 3550260. Same caption as in Fig.A.5.


  \begin{figure*}\par\psfig{figure=3550300.ps,width=17.5cm}\end{figure*} Figure A.28: ESO-LV 3550300. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=3570190.ps,width=17.5cm}\end{figure*} Figure A.29: ESO-LV 3570190. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=4050180.ps,width=17.5cm}\end{figure*} Figure A.30: ESO-LV 4050180. Same caption as in Fig.A.5.


  \begin{figure*}\par\psfig{figure=4050180.ps,width=17.5cm}\end{figure*} Figure A.31: Upper left: ESO-LV 4060250 image from the STScI Digitized Sky Survey (8$' \times$ 8'). North is to the top and East is to the left. Numbers along the major axis corresponds to positions spaced by half of a beamwidth (23''). Circle on the bottom left corresponds to the size of the SEST beam at 115GHz (12CO(1-0)) 45''. Upper right, bottom left and right: spectrum at 115GHz (12CO (1-0)) taken at positions 1, 2 and 3. Intensities are in mK.


  \begin{figure*}\par\psfig{figure=4050180.ps,width=17.5cm}\end{figure*} Figure A.32: Upper and bottom left: ESO-LV 4060250 spectrum at 115GHz (12CO (1-0)) taken at position 4 and 6. Upper and bottom right: spectrum at 115GHz (12CO (1-0)) taken at position 5 and 7. Intensities are in mK.


  \begin{figure*}\par\psfig{figure=4060330.ps,width=17.5cm}\end{figure*} Figure A.33: ESO-LV 4060330. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=4070140.ps,width=17.5cm}\end{figure*} Figure A.34: ESO-LV 4070140. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=4190030.ps,width=17.5cm}\end{figure*} Figure A.35: ESO-LV 4190030. Same caption as in Fig.A.2.

Appendix A: The Database - Cont.


  \begin{figure*}\par\setcounter{figure}{35} \psfig{figure=4200030.ps,width=17.5cm}\end{figure*} Figure A.36: ESO-LV 4200030. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=4710200.ps,width=17.5cm}\end{figure*} Figure A.37: ESO-LV 4710200. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=4780060.ps,width=17.5cm}\end{figure*} Figure A.38: ESO-LV 4780060. Same caption as in Fig.A.1.


  \begin{figure*}\par\psfig{figure=4820430.ps,width=17.5cm}\end{figure*} Figure A.39: ESO-LV 4820430. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=4840250.ps,width=17.5cm}\end{figure*} Figure A.40: ESO-LV 4840250. Same caption as in Fig.A.5.


  \begin{figure*}\par\psfig{figure=5320090.ps,width=17.5cm}\end{figure*} Figure A.41: ESO-LV 5320090. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=5390050.ps,width=17.5cm}\end{figure*} Figure A.42: ESO-LV 5390050. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=5450100.ps,width=17.5cm}\end{figure*} Figure A.43: ESO-LV 5450100. Same caption as in Fig.A.1.


  \begin{figure*}\par\psfig{figure=5450110.ps,width=17.5cm}\end{figure*} Figure A.44: ESO-LV 5450110. Same caption as in Fig.A.5.


  \begin{figure*}\par\psfig{figure=5480070.ps,width=17.5cm}\end{figure*} Figure A.45: ESO-LV 5480070. Same caption as in Fig.A.5.


  \begin{figure*}\par\psfig{figure=5480310.ps,width=17.5cm}\end{figure*} Figure A.46: ESO-LV 5480310. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=5480380.ps,width=17.5cm}\end{figure*} Figure A.47: ESO-LV 5480380. Same caption as in Fig.A.2.


  \begin{figure*}\par\psfig{figure=6010040.ps,width=17.5cm}\end{figure*} Figure A.48: ESO-LV 6010040. Same caption as in Fig.A.1.

Copyright ESO 2002