Abstract.We report the detection of the 405 nm band of interstellar C3 in absorption toward HD 210121. The abundance of triatomic carbon is approximately 1/17 of that of diatomic carbon in the same diffuse molecular cloud. Rotational levels of C3 up to J = 14 are seen in this cloud. The rotational excitation of C3 in the interstellar medium may reflect a competition between inelastic collisions, formation and destruction of the molecule, and radiative pumping in the far-infrared. The abundance of C3 is compared with chemical models. Attention is called to molecular properties that need to be better determined.

Abstract.To investigate the presence of small scale structure in the spatial distribution of H 2 molecules we have undertaken repeated FUSE UV observations of the runaway O9.5V star, HD 34078. In this paper we present five spectra obtained between January 2000 and October 2002. These observations reveal an unexpectedly large amount of highly excited H 2 . Column densities for H 2 levels from (v = 0, J = 0) up to (v = 0, J = 11) and for several v = 1 and v = 2 levels are determined. These results are interpreted in the frame of a model involving essentially two components: i) a foreground cloud (unaffected by HD 34078) responsible for the H 2 (J = 0, 1), CI, CH, CH + and CO absorptions; ii) a dense layer of gas (n 10 4 cm −3 ) close to the O star and strongly illuminated by its UV flux which accounts for the presence of highly excited H 2 . Our model successfully reproduces the H 2 excitation, the CI fine-structure level populations as well as the CH, CH + and CO column densities. We also examine the time variability of H 2 absorption lines tracing each of these two components. From the stability of the J = 0, 1 and 2 damped H 2 profiles we infer a 3σ upper limit on column density variations ∆N(H 2 )/N(H 2 ) of 5% over scales ranging from 5 to 50 AU. This result clearly rules out any pronounced ubiquitous small scale density structure of the kind apparently seen in HI. The lines from highly excited gas are also quite stable (equivalent to ∆N/N ≤ 30%) indicating i) that the ambient gas through which HD 34078 is moving is relatively uniform and ii) that the gas flow along the shocked layer is not subject to marked instabilities.

We present data from high-dispersion echelle spectra and simultaneous uvby photometry for γ Doradus. These data were obtained from several sites during 1994 November as part of the MUSICOS-94 campaign. The star has two closely-spaced periods of about 0.75 d and is the brightest member of a new class of variable early F-type stars. A previously suspected third period, very close to the other two, is confirmed. Previous observations indicated that sudden changes could be expected in the spectrum, but none were found during the campaign. The radial velocities rule out the possibility of a close companion. The phasing between the radial velocity and light curve of the strongest periodic component rules out the starspot model. The only viable mechanism for understanding the variability is nonradial pulsation. We used the method of moments to identify the modes of pulsation of the three periodic components. These appear to be sectorial retrograde modes with spherical harmonic degrees, (ℓ, m), as follows: f 1 = (3,3), f 2 = (1,1) and f 4 = (1,1). The angle of inclination of the star is found to be i ≈ 70 • .

Abstract. As part of our efforts to unveil extragalactic large-scale structures behind the southern Milky Way, we here present redshifts for 764 galaxies in the Hydra/Antlia, Crux and Great Attractor region (266 . A total of 947 galaxies have been observed, a small percentage of the spectra (N = 109, 11.5%) were contaminated by foreground stars, and 74 galaxies (7.8%) were too faint to allow a reliable redshift determination. With MEFOS we obtained spectra down to the faintest galaxies of our optical galaxy survey, and hence probe large-scale structures out to larger distances (v < ∼ 30 000 km s −1 ) than our other redshift follow-ups using the 1.9-m telescope at the South African Astronomical Observatory (Kraan-Korteweg et al. 1995;Fairall et al. 1998;Woudt et al. 1999) and the 64-m Parkes radio telescope (Kraan-Korteweg et al. 2002). The most distinct large-scale structures revealed in the southern Zone of Avoidance are discussed in context to known structures adjacent to the Milky Way.

Abstract. We present a catalogue of velocities for 551 galaxies (and give the coordinates of 39 stars misclassified as galaxies in our photometric plate catalogue) in a region covering about 100 × 100 (0.94×0.94 Mpc for an average redshift of 0.0555, assuming H 0 =50 km s −1 Mpc −1 ) in the direction of the rich cluster ABCG 85. This catalogue includes previously published redshifts by Beers et al. (1991) and Malumuth et al. (1992), together with our 367 new measurements. A total of 305 galaxies have velocities in the interval 13350−20000 km s −1 , and will be considered as members of the cluster. ABCG 85 therefore becomes one of the clusters with the highest number of measured redshifts; its optical properties are being investigated in a companion paper.Key words: galaxies: clusters: individual: ABCG 85; galaxies: distances and redshifts -instrumentation: spectrographs 1. Observations and data reduction Description of the observationsThe observations were performed with the ESO 3.6 m telescope equipped with MEFOS (see description below) during 6 nights on November 5-11, 1994 and 2 nights on November 24-26, 1995. The grating used with the Boller & Chivens spectrograph had 300 grooves/mm, giving a dispersion of 224Å/mm in the wavelength region Send offprint requests to: F. Durret, durret@iap.fr Based on observations collected at the European Southern Observatory, La Silla, Chile. Table 3 is also available in electronic form at CDS, Table 4 is only available in electronic form at CDS via anonymous ftp strasbg.fr/Abstract.html 3820−6100Å. The detector was CCD #32, with 512 2 pixels of 27 × 27 µm.The catalogue of galaxy positions used in this survey was obtained with the MAMA measuring machine and is presented in a companion paper ). This catalogue gives approximate magnitudes in the b J band, which were used to select the galaxies to be observed spectroscopically. CCD photometry of the central regions of the cluster in the V and R bands was later performed to recalibrate b J magnitudes and obtain V and R magnitudes for the entire photometric sample. We observed spectroscopically a total number of 21 fields, with exposure times of 2×20 minutes for the two fields with galaxies all brighter than b J = 18, and 2×30 minutes for the other ones. We obtained 519 spectra in total (plus the same number of sky spectra).

The results of spectroscopic observations of 46 R º 1 clusters of galaxies from the Abell and Abell, Corwin, & Olowin (hereafter ACO) catalogs are presented. The observations were conducted at the ESO 3.6 m telescope with the Meudon-ESO Fibre Optics Spectrograph (MEFOS) multiple-Ðber spectrograph. Thirty-nine of the clusters lie in a 10¡ ] 45¡ strip of sky that contains two supercluster candidates (in Aquarius and Eridanus). These candidates were identiÐed by a percolation analysis of the Abell and ACO catalogs, using estimated redshifts for clusters that had not yet been measured. With our measurements and redshifts from the literature, the target strip is now 85% complete in redshift measurements for R º 1 ACO clusters with Seven other clusters were observed in a supercluster candidate m 10 ¹ 18.3. in the Grus-Indus region. Seven hundred thirty-seven galaxy redshifts were obtained in these 46 cluster Ðelds. We Ðnd that one of the supercluster candidates is a collection of 14 R º 1 ACO/Abell clusters with a spatial number density that is 20 times the average spatial density for rich ACO clusters. This overdensity has a maximum extent of D110 h~1 Mpc, making it the longest supercluster composed only of R º 1 clusters to be identiÐed to date. This Ðlament of clusters runs within 6¡ of the line of sight in the Aquarius region, and, on its high-z end, four R \ 0 ACO clusters (three of which are R \ 1 in the Abell catalog) appear to bridge gaps to other clusters, extending the structure to D150 h~1 Mpc. Our analysis also reveals that another supercluster, consisting of eight rich clusters with an extent of D75 h~1 Mpc, runs roughly perpendicular to Aquarius near its low-redshift end. Both of these superclusters are remarkably Ðlamentary. Fitting ellipsoids to all N º 5 clumps of clusters (at b \ 25 h~1 Mpc) in the measured-z Abell/ACO R º 1 clusters sample, we found two other superclusters with axis ratios º3 (long-to-midlength axis). The frequency of such Ðlaments (D20%) was nearly identical with that found among "" superclusters ÏÏ in Monte Carlo simulations of random and random-clumped cluster samples, however, so the Abell/ACO clusters have no particular tendency toward Ðlamentation. The Aquarius and Aquarius-Cetus superclusters, in this one region of the sky, have axis ratios of 4.3 and 3.0, respectively. The Aquarius Ðlament also contains a "" knot ÏÏ of six R º 1 clusters at z D 0.11, with Ðve of the clusters close enough together to represent an apparent overdensity of 150There are three other n6 . R º 1 cluster density enhancements similar to this knot at lower redshifts : Corona Borealis, the Shapley concentration, and another grouping of seven clusters in Microscopium. All four of these dense superclusters appear near the point of breaking away from the Hubble Ñow, and some may now be in collapse, but there is little indication of any being virialized. With four such objects, studies of them as a class may now lead to much greater insight into large-scale processes.

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