University of Groningen The HI distribution of spiral galaxies in the cluster A 262 Bravo-Alfaro, H.; Szomoru, A.; Cayatte, V.; Balkowski, C.; Sancisi, R. Published in: Astronomy & astrophysics supplement series DOI: 10.1051/aas:1997281 IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 1997 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Bravo-Alfaro, H., Szomoru, A., Cayatte, V., Balkowski, C., & Sancisi, R. (1997). The HI distribution of spiral galaxies in the cluster A 262. Astronomy & astrophysics supplement series, 126(3), 537-546. https://doi.org/10.1051/aas:1997281 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license. More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne- amendment. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date: 29-09-2021 ASTRONOMY & ASTROPHYSICS DECEMBER II 1997, PAGE 537 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 126, 537-546 (1997) The HI distribution of spiral galaxies in the cluster A 262? H. Bravo-Alfaro1,A.Szomoru2,3, V. Cayatte1 , C. Balkowski1, and R. Sancisi2 1 Observatoire de Paris, DAEC and URA 173, associ´e au CNRS eta ` l’Universit´e Paris 7, 92195 Meudon Cedex, France 2 Kapteyn Astronomical Institute, P.O. Box 800, NL 97000 AV Groningen, The Netherlands 3 UCO/Lick Observatory, University of California, Santa Cruz, California 95064, U.S.A. Received October 31, 1996; accepted April 21, 1997 Abstract. We present results of an Hi survey of the clus- been shown that cluster galaxies can be substantially de- ter of galaxies Abell 262, using the Westerbork Synthesis ficient in neutral hydrogen. The Hi content of individual Radio Telescope (WSRT). Eleven galaxies were detected galaxies depends on the distance from the cluster cen- in five fields. In a few cases the gas in these galaxies ter, with the most gas deficient objects near the core. shows an asymmetrical distribution; the most likely expla- Furthermore, the Hi deficiency of the cluster is also corre- nation is the interaction between the cluster medium and lated with its X–ray luminosity. the gaseous disks. Only two of the detected galaxies are In order to obtain more information on the spatial dis- slightly Hi-deficient. At 4000 to the West of CGCG 160 − tribution of the neutral hydrogen in deficient galaxies in 049 we tentatively detect what may be an associated Hi A 262, 21 cm line observations were done with the WSRT. 8 cloud. The total mass of this cloud is 2.510 M , and no Five fields were surveyed, centered between 0.07 and 0.70 ◦ optical counterpart has yet been found. rA (the Abell radius rA, equals 1.75 for A 262), covering a significant part of the core of the cluster where we searched Key words: galaxies: clusters: individual: Abell 262 — for galaxies already detected by Giovanelli et al. (1982), radio lines: galaxies Giovanelli & Haynes (1985) and Wegner et al. (1993). We describe the observations and the data reduction in Sect. 2. Results are given in Sect. 3, where we present the total Hi maps of eleven galaxies superposed on optical images from the Digitized Sky Survey (DSS). For some 1. Introduction of these galaxies (NGC 688 and NGC 753), we show the intensity weighted velocity fields, and position velocity di- This paper describes Hi observations of eleven galaxies in agrams along the major axis (for NGC 688, NGC 753 and the cluster Abell 262. This is a spiral rich cluster, classed UGC 1347). Our conclusions are summarized in Sect. 4. III in the Bautz-Morgan system and characterized by the X–ray source 3U 015 + 36, located near the core and concentric with respect to the elliptical galaxy NCG 708. 2. Observations and data reduction Its X–ray luminosity (L =3.09 1043 ergs s−1; Jones & x The observations were done in 1984 with the WSRT Forman 1984) is comparable to that of the Virgo cluster. (H¨ogbom & Brouw 1974). Each pointing was observed Its relatively low redshift (z =0.0156) combined with its for 12 hours, with a total bandwidth of 10 MHz and wealth of spirals, makes it an interesting cluster for a study 31 frequency channels, resulting in a channel spacing of of the Hi content of its member galaxies as a parameter 68 km s−1. The velocity resolution is 1.2 times the ve- of environmental conditions. locity spacing between adjacent channels. The calibration The 21 cm line of neutral hydrogen is a very useful tool was done according to the standard WSRT procedures, de- for probing the evolution of spirals in a cluster environ- scribed by van Someren-Greve (1974). The observational ment. Through comparisons of the Hi content of isolated parameters are shown in Table 1. galaxies with galaxies in Virgo (Chamaraux et al. 1980; For the observed fields the synthesized beam is about Giovanelli & Haynes 1983; Cayatte et al. 1990, 1994), and 1300 × 2000. Our final sample consists of ten spirals and in other clusters (e.g. Giovanelli & Haynes 1985) it has one irregular out of nearly 30 candidates. Only two of the Send offprint requests to: H. Bravo-Alfaro; Observatoire de detected galaxies (NGC 710 and CGCG 522 − 049) are Paris, F-92195 Meudon Cedex, France. slightly Hi deficient. ? Based on observations done at the Westerbork Synthesis The WSRT data reduction program NEWSTAR was Radio Telescope, in The Netherlands. used to transform the UV data to (α, δ, Vhel) cubes. 538 H. Bravo-Alfaro et al.: Hi distribution of galaxies in A 262 Table 1. Observational parameters (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) Field α1950 δ1950 tint Beam size Bandwidth Central vel. ∆v rms mJy-K conv. (h m s) ◦000 (hrs.) 00 (MHz) (km s−1)(kms−1) mJy/beam mJy/beam 1 1 45 00.0 36 00 00.0 12 12.4 × 19.3 10 4700 68.1 0.89 0.37 2 1 47 00.0 35 05 00.0 12 15.2 × 21.6 10 4750 68.1 0.95 0.52 3 1 49 30.0 35 50 00.0 12 15.6 × 21.2 10 5400 68.1 1.04 0.53 4 1 51 00.0 36 25 00.0 12 11.7 × 19.5 10 5100 68.1 0.93 0.36 5 1 53 00.0 35 50 00.0 12 13.7 × 22.0 10 5000 68.1 0.86 0.48 Column 1: Field number. Columns 2 and 3: R.A. and Dec. (1950) of each pointing. Column 4: Integration time. Column 5: Minor and major axes of the synthesized beams, in seconds of arc. Column 6: Total observed bandwidth in MHz. Column 7: Heliocentric velocity of the central channel. Column 8: Channel separation in km s−1. The velocity resolution is equivalent to 1.2 times this velocity spacing. Column 9: rms noise per channel after continuum subtraction, in mJy/beam. Column 10: The flux density per beam area (in mJy/beam) equivalent to 1.0 K in the channel maps. Table 2. Observed galaxies (1) (2) (3) (4) (5) (6) (7) (8) (9) 10 Name α1950 δ1950 Type mag a × biPA r/rA Hi Def (1) NGC 668 1 43 27.2 36 12 40 Sb 12.64 1.8 × 1.2501 331 0.77 0.03 (2) UGC 1257 1 45 11.3 36 12 13 Sab 14.59 1.0 × 0.5642 1072 0.57 0.11 (3) UGC 1277 1 46 30.7 35 12 14 S0a 14.03 1.7 × 0.9622 752 0.55 0.22 (4) UGC 1299 1 47 37.6 35 06 39 Im 15.69 1.0 × 0.6652 852 0.53 −0.17 (5) NGC 688 1 47 48.8 35 02 13 SBb(rs)p 12.43 2.4 × 1.5551 1461 0.56 0.10 (6) NGC 710 1 49 57.5 35 48 26 Scd 13.79 1.7 × 1.7192 514 0.06 0.38 (7) UGC 1347 1 49 49.0 36 22 21 SABc(rs) 13.23 1.3 × 1.1301 181 0.26 −0.07 (8) CGCG 522−049 15053.7 361907 SBd1 15.10 0.9 × 0.7452 1493 0.26 0.33 (9) UGC 1361 1 50 56.21 36 20 271 Scd 15.43 1.1 × 0.4732 1313 0.27 0.12 (10) UGC 1387 1 52 13.8 36 01 00 Sdm 15.37 0.9 × 0.6482 1752 0.27 −0.06 (11) NGC 753 1 54 45.4 35 40 22 SABbc(rs) 11.66 2.5 × 2.0501 1281 0.58 −0.15 Column 1: Galaxy identification.