ASTRONOMY & ASTROPHYSICS OCTOBER I 1999,PAGE1 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 139, 1–24 (1999)

HI observations of blue compact from the first and second Byurakan surveys?

1 , 3 ,2 4 2 Trinh X. Thuan , V.A. Lipovetsky† , J.-M. Martin , and S.A. Pustilnik 1 Astronomy Department, University of Virginia, Charlottesville, VA 22903, U.S.A. e-mail: [email protected] 2 Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnij Arkhyz, Karachai-Circessia 357147, Russia e-mail: [email protected] 3 D´epartement d’Astronomie Extragalactique et de Cosmologie, Observatoire de Paris, F-92195 Meudon Cedex, France 4 D´epartement de Radioastronomie ARPEGES, Observatoire de Paris, F-92195 Meudon Cedex, France e-mail: [email protected]

Received August 11; accepted November 24, 1998 Abstract. We present the results of a neutral hydrogen et al. 1996). Their optical spectra show strong narrow survey of 79 galaxies from a statistical sample of 88 emission lines on top of a stellar continuum which is Blue Compact Galaxies (BCGs) selected from the First rising towards the blue, similar to spectra of HII regions, and Second Byurakan objective prism surveys to have and indicating the presence of a large population of a HII region-like spectrum, an equivalent width of the massive OB . Much attention has been devoted to [O III] λ5007 line larger than 50 A,˚ and a veloc- BCGs since their discovery by Sargent & Searle (1970), 1 ∼ ity 6000 km s− . The detection rate for the statisti- because of the realization that BCGs best approximate cal≤ sample is 74%. HI range between 4 107M young galaxies, as implied by their low metallicity and 5 109M with the HI distribution peaking at (Z /50

2) The HI flux allows to determine the neutral atomic (Markarian et al. 1989) and a few BCGs from the Case gas mass and the width of the HI profile yields an esti- Survey (Pesch & Sanduleak 1987) in the same sky area and mate of the total mass of the BCG. The gas mass frac- satisfying the same selection criterion. The resulting sam- tion combined with abundance measurements are crucial ple contains a total of 220 BCGs (Izotov et al. 1993). The for testing chemical evolution models of BCGs, such as distribution of the total sample along with the closed-box models, models with galactic winds or infall, large-scale space distribution are given in Pustilnik et al. etc. (Lequeux et al. 1979; Pilyugin 1993; Marconi et al. (1995). The BCG sample is reasonably complete out to 1 1994; Peimbert et al. 1994; Carigi et al. 1995; Pustilnik 10000 km s− , with increasing incompleteness beyond. et al. 1996). The≈ redshift distribution shows 3 peaks, one at V 1000 1 ≈ 3) Combining with other data, the HI data permit to km s− due to the Virgo cluster, and two additional peaks 1 1 derive global parameters of BCGs (such as M(HI)/L at V 3000 km s− and V 7000 10000 km s− .In B ≈ ≈ − or M(total)/LB, study general trends and correlations order not to spend inordinately large amounts of telescope (for example M(HI)/LB vs. LB) suggested by various time on a single galaxy and still reach interesting upper galaxy formation theories and compare with other types limits for the BCG HI content with a given telescope sen- of galaxies. For example, one question of great interest sitivity, we have extracted a complete subsample of 88 is the relationship between BCGs and another class of BCGs by further imposing a lower limit on the equiva- dwarf galaxies, the low-surface-brightness (LSB) dwarfs. lent width of the [O III]λ5007 emission line of 50 A,˚ and 1 Star formation in BCGs is known to occur in bursts last- a velocity upper limit of 6000 km s− . ing 108 yr, separated by long quiescent periods of Of these 88 BCGs, 10 were already observed in ear- 2 310≤ 9 yr (Thuan 1991). If LSB dwarfs are BCGs in lier studies (Thuan & Martin 1981; Gordon & Gottesman their− quiescent phases, then their HI properties should be 1981). We have obtained new HI observations for 77 statistically similar (Thuan 1985). The HI data obtained BCGs, and obtained measurements with better signal-to- here can be compared statistically with the large HI data noise ratio of two BCGs with published data. One BCG set for LSB dwarfs assembled by Schneider, Thuan and which is close to a HI rich galaxy with the same velocity their colleagues (1990, 1992) to test the above hypothesis. was not observed. Finally, a HI single-dish survey allows to judge the feasibil- This complete subsample will be used for statistical ity of follow-up HI interferometric studies of particularly studies in a subsequent paper. For comparison, we have interesting objects in the sample. observed in addition 20 BCGs in the SBS zone with V 1 ≤ The first comprehensive HI survey of BCGs was carried 6000 km s− but with less strong emission lines, 47 BCGs out by Thuan & Martin (1981). These authors assembled not in the SBS zone with the same velocity limit, and 17 1 a list of 115 blue compact dwarfs known at that time from BCGs in the SBS zone with 6000 V 14000 km s− , ≤ ≤ the objective prism surveys of Markarian and Haro, with which are of particular astrophysical interest. Finally 8 1 a few objects from Zwicky and other investigators. Other more BCGs outside the SBS zone with V 6000 km s− ≥ HI surveys of BCGs followed, such as that of Gordon & were observed. Altogether we have obtained HI parame- Gottesman (1981) which included mainly brighter BCGs ters or upper limits for 171 BCGs. (MB < 18) from the Markarian, Haro and Zwicky lists, We discuss the HI observations and the data reduc- that of Hoffman− et al. (1992) for BCGs in the Virgo clus- tion in Sect. 2. In Sect. 3 we describe the data tables and ter, and that of Staveley-Smith et al. (1992) for a small present the observed HI profiles. We give a preliminary sample of nearby BCGs. discussion of the data in Sect. 4. A more complete discus- The BCG sample we are concerned with here was pri- sion is deferred to a subsequent paper. marily assembled from objective prism survey plates ob- tained with the 1 m Schmidt Telescope at the Byurakan Observatory during the Second Byurakan Survey (SBS; 2. Observations and data reduction Markarian et al. 1983). The objective prism plates cover h m h m The 21 cm observations were carried out in 1992–1996 the sky area defined by 7 40 α 17 20 ,49◦ ≤ ≤ ≤ 1 2 δ 61◦, an area of about 1000 square degrees. All objects with the Nan¸cay 300-m and Green Bank 43-m radio with≤ prism spectra showing strong or moderate emission telescopes. lines were observed spectroscopically with the 6m tele- The Nan¸cay radio telescope has a half-power scope of the Special Astrophysical Observatory. Then all beam width (HPBW) of 3.70 (EW) 220 (NS) at the × emission-line galaxies with a HII region-like spectrum and 1 The Nan¸cay Radioastronomy Station is part of the Paris an equivalent width of the [O III] λ5007 emission line Observatory and is operated by the Minist`eredel’Education´ larger than 30 A,˚ were selected to constitute the BCG ≈ Nationale and Institut des Sciences de l’Univers of the Centre sample. The above criterion excluded massive nuclear star- National de la Recherche Scientifique. burst galaxies and galaxies with an 2 The Green Bank Observatory is part of the National Radio such as Seyfert galaxies and quasars. In addition, we have Astronomy Observatory, which is operated by Associated also added 50 BCGs from the First Byurakan Survey Universities, Inc. for the National Science Foundation. ∼ Trinh X. Thuan et al.: HI observations of blue compact galaxies 3 declination δ =0◦. We used a dual-polarization receiver, 3. Results with a system temperature of 40 K in the horizontal linear polarization and 40 K≈ and 60 K in the vertical We present the data in three tables. Table 1 gives the data linear polarization in the≈ periods 1992–1994 and 1995 for the galaxies for which we feel the HI results are secure. respectively. As all the candidate BCGs had known This means we are relatively certain that the signal is optical from the 6m spectroscopic observations, not produced by confusion or receiver baseline anomalies, we split the 1024-channel autocorrelator into two, cover- and that the signal-to-noise value is adequate. Table 2, on ing a bandwidth of 6.4 MHz each, and centered at the the other hand, lists detections of emission which may be frequency corresponding to the optical redshift. In this all right, but for various reasons such as confusion or a configuration, each segment covered a velocity range of low signal-to-noise ratio, we feel should be used more cau- 1350 km s 1. The channel spacing was 2.6 km s 1 before − − tiously. Table 3 lists the undetected galaxies and upper smoothing and the effective resolution after averaging limits for their HI flux densities. pairs of adjacent channels and Hanning smoothing was 1 The cut-off between Table 1 and Table 2 is not rigor- 21 km s− . The gain of the telescope was 1.1 K/Jy at ≈ ously defined as it is based on a mixture of subjective the declination δ =0◦. The observations were made in the standard total power (position switching) mode with evaluation of the HI profiles as well as more objective 2-minute on-source and 2 minute off source integrations. guidelines. The possibility of confusion was checked for Typically, we aim to achieve a rms noise of 2.5 mJy per every galaxy by using the Lyon-Meudon Extragalactic channel, after smoothing the channel spacing to 21 km Database (LEDA) to generate sky plots of a circular area 1 of radius 300 centered on the galaxy. This allows also to s− . This leads to a typical integration time of 1 hour on the galaxy and 1 hour on the comparizon field. For BCGs check for the environment of the galaxy, whether it is with the faintest HI flux densities, the ON integration isolated or in a group. The properties and angular sep- time may go up to 3-4 hours. Since the calibration noise arations of possible companion galaxies are given in the diode power has changed significantly over the years, Notes to Tables 1 and 2. There is generally a signal-to- and since its power is frequency-dependent, we have noise ratio lower limit of 4 for inclusion in Table 1. The exercised great care in improving the standard Nan¸cay signal is measured as the peak flux in the galaxy’s HI pro- radio telescope calibration method to correct the data for file, while the noise is measured in the baseline away from the time and frequency dependencies. This procedure is the observed signal. In a few cases, repeated observations detailed in Appendix A. yielded essentially the same parameters, and although the signal-to-noise ratio remained low, we have included the The NRAO 43 m radio telescope has a HPBW of 220. galaxies in Table 1. We use a two channel dual-polarization prime-focus re- Tables 1 and 2 include all of the basic information ceiver with a system temperature of 20 K in both po- ≈ 1 about the galaxies and the observations, along with the larizations. A bandwidth of 20 MHz covering 4225 km s− optical angular size information used in calculating cor- was used with the 1024-channel autocorrelator split in 1 rections to the measured HI fluxes. They are organized as two. The channel spacing was 8kms− and the effec- follows: tive resolution after Hanning smoothing≈ was 16 km s 1. − Column (1). Name following the IAU nomenclature. The observations were also made in the position≈ switching Some BCGs in physical pairs are characterized by addi- mode, with 6 minutes off-source and 6 minutes on-source tional letters (A, B, N = North, E = East), but in the ta- integrations. The calibration signal levels and telescope bles the two components are lumped together in the same pointing errors were checked by observing standard cali- name entry, as they are not resolved by the radio telescope brators listed in the 43 m Telescope Observer’s Manual. beam. The BCGs which are in the statistical sample are The calibration noise diode temperature was measured in marked by a cross in all tables. Galaxies marked by an the laboratory before the observing run. The gain of the asterisk in Table 2 are non-confused. telescope was 0.29 K/Jy. Column (2). Cross-references to other names in the The Green Bank data was reduced using NRAO’s stan- Markarian (MK, Markarian et al. 1989), Michigan (UM, dard LINE program, while the Nan¸cay data was reduced Salzer et al. 1989) or in the Case (CG, Pesch et al. using the software developed by the telescope’s staff. For 1991) lists. When the galaxy is from the Second Byurakan each integration, the two polarizations which were de- Survey (Markarian et al. 1983; Stepanian et al. 1993a–d), tected independently were averaged to improve sensitivity. it is designated by the initials SBS. The baselines were generally well fitted by a polynomial Columns (3) and (4). Right ascension and declination of third order or lower and subtracted out. at the epoch 1950. The coordinates have been measured To check that the data taken from the two telescopes either from the Palomar Sky Survey prints or plates, or are on the same flux scale, we have observed several galax- taken to be the pointing coordinates of the 6 m telescope ies with both telescopes. To within the errors, the Nan¸cay during the spectroscopic observations. The errors in each and Green Bank fluxes agree with each other. coordinate are typically between 1 and 5 arcsec. 4 Trinh X. Thuan et al.: HI observations of blue compact galaxies

Table 1. HI detections of BCGs R N

(HI)/ & M M 1 − 0.32 8.77 N94* 0.38 8.40 N94* 0.220.600.25 8.950.12 9.35 7.86 N94 7.70 N94 N94 N95* 0.36 8.290.20 N94* 8.66 N95 0.250.260.35 8.950.22 9.27 9.69 N93* 9.29 N95 N96* N94* 0.220.20 9.070.20 8.160.19 N94* 9.43 N94* 8.960.40 N94* 0.22 N94* 9.08 8.38 N94* N94* 0.170.23 8.90 9.56 N94* N94 0.15 8.62 N93* 0.350.38 9.43 9.66 N94* N94* 0.14 8.11 N95* 0.36 8.34 N94* 0.18 8.68 N96* 0.36 9.78 N93 0.260.29 9.27 9.26 N93 N95* 0.24 9.24 N94* 0.21 8.02 N94* 0.12 8.44 N94* 0.48 8.93 N93 0.20 8.68 N93 0.25 8.98 N93* ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Jy km s 1 − 0.32 1.97 0.970.37 2.50 0.900.730.810.95 8.71 G91* 8.53 8.620.22 G92* 0.60 0.72 8.38 G92* 0.25 4.08 8.710.12 0.37 G91 0.71 G91 0.36 1.16 0.20 1.01 0.250.26 0.97 0.35 1.73 0.22 4.79 1.80 0.220.20 0.92 1.30 0.200.19 2.02 0.68 0.360.22 6.76 1.33 0.17 0.58 0.23 2.79 0.15 0.63 0.340.37 1.93 3.32 0.14 2.72 0.36 1.32 0.18 3.16 0.670.720.36 8.71 1.88 G92* 9.90 G92* 0.26 0.84 0.29 2.21 0.24 1.97 0.20 0.84 1.24 8.78 G92* 0.55 8.56 G92* 0.12 0.24 0.80 8.78 G92 0.46 8.74 0.20 0.76 1.24 9.20 G92* 0.22 1.45 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Jy km s Obs. Flux Cor. Flux Log 1 21 1.96 1560 3.06 2.46 3812 2.19 4.54 1433 3.17 3.47 5420 0.72 25 4.05 16 0.37 0.71 67 1.15 34 0.99 3340 0.96 30 1.72 29 4.74 1.78 4165 0.90 1.26 1424 1.99 0.67 1726 5.96 1.32 77 0.58 15 2.72 40 0.62 9412 1.89 3.29 06 2.71 20 1.32 03 3.14 11 4.30 10 6.65 55 1.86 50 0.83 37 2.18 33 1.96 24 0.79 44 7.52 10 1.81 32 0.24 38 2.63 08 8.50 56 0.75 52 2.86 14 1.28 − 20 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± W km s 1 13 99 0939 130 190 2408 101 125 0921 135 142 3413 106 16 179 01 63 84 43 200 22 106 2125 274 19 169 18 211 190 2642 171 177 2915 152 128 1116 198 117 49 150 10 276 29 156 6008 216 183 04 84 13 95 02 137 07 122 07 100 35 225 32 119 23 179 21 147 15 116 28 153 07 92 20 63 24 182 05 136 36 179 33 189 09 105 − 50 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± W Mpc km s 1 1 61.3 81 07 35.4 65 0519 26.7 20.612 120 04 127 25.6 19.704 80 11 106 17.9 25.0 124 117 1707 72.608 48.105 53 28.7 156 17.2 42 53 21 26.711 144 44.0 53 1013 62.710 67.509 253 65.8 116 67.4 137 137 1321 73.3 21.705 149 08 83 75.0 75.2 129 05 112 08 27.3 27.8 149 83 25 76.305 91 74.2 252 17 52.7 119 3004 77.1 76.2 109 167 02 14.2 53 06 26.5 52 01 25.4 127 04 22.403 104 71.3 72 17 116.3 176 16 96.812 79 58.8 126 08 23.1 95 14 18.4 90 04 29.1 82 10 69.6 42 12 31.2 154 03 20.2 106 18 51.6 126 17 48.6 158 05 52.8 83 − ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± (HI) Dist. V 907 4441 751 2323 1177 5157 1740 5564 5490 1358 3582 5 3256 0 1583 0 8754 0 7065 0 4925 0 4043 20 1594 20 2940 1060 4420 60 4945 40 4619 4740 4530 5514 1622 2045 5508 5694 9015 2098 2133 30 5488 45 5292 30 3974 25 1512 60 4120 60 1562 30 30 15 40 50 10 45 25 40 45 60 − − − − − − − − − − − e e e e e e e e e e e e e 15 30 29 39 19 26 19 14 31 15 26 28 27 21 32 27 23 60 18 25 26 12 21 25 13 10 50 17 20 45 16 25 36 43 13 × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × axb Vir 30 60 32 44 22 48 24 23 46 28 35 43 30 40 47 27 42 26 60 36 14 65 25 26 20 62 37 32 44 35 58 26 105 117 35 07 24 23 16 14 2360 05 35 23 21 12 26 ◦000 06 10 03 14 10 05 − − − − − − prefix h m s name or R.A. Dec. size km s MK1409 07SBS 41 34.8 074937.8 53 32 564941 55 MK1416MK116 09 17 25.7 09 30 30.2SBS 52 46MK1424 53 55 27 47 09MK22 42 56.4 09 40 50.8SBS 57 09 20 46SBS 55 54 03.4 25 18SBS 10 01 20.7SBS 55 48 49SBS 10 33 30.6 55 10 33 111410.7 37 18 42.1MK1446 584722 111945.7MK193 583605 53 06 34 11SBS 24 49 45.5 28 05SBS 11 52 51.9SBS 120343.2 54 11MK1468 591459 25 1638 120557.5 57SBS 554208 56 34 121134.0 12SBS 13 540158 34.8 1551 SBS 124130.3 545511 1116 131742.9 59 47 521957 09 131807.6 520137 986 1496 MK546 00 12 01.6 01 49 43 SBS 100612.1 574845 MK996UM133 01 25 04.6 01 42 05.3MK1030 02 04 14 38 39.2 25MK1042MK1182 29 02 17 25 27 38.0 02 37 54.8 16 37 00 SBSMK99 1623 081352.7 521156 08 5262 47 25.2 61 12 29 MK1410 07 43 10.0 55 04 15 MK1423 09 39 24.4 59 12 08 MK170 11 23 55.8 64 24 48 988 MK1426 09 46 03.1 48 47 49 1835 SBS,HS 13 23 13.1 48 18 01 MK953 00 34 30.8 35 37 39 MK564 01 11 12.1 07 31 07 MK1006 01 43 33.4MK1031 34 02 40 16 40 20.3 MK1069 03 05 57.5 MK93SBS 08 32 09.7 091639.1 541911 66 24 23 MK119 09 40 10.7 66 12 25 3316 MK1039 02 25 06.2 SBS 03 35 15.1 + + + + + + + + + + + + + + + + + + + + + A UM369 01 44 29.0 02 26 38 A 018 573 555 578 494 587 065 046 024 292 104 166 521 612 550 568 592 644 554 487 592 557 540 597 586 579 549 523 520 483 356 075 531 346 032 140 664 543 662 541 558 103 052 527 544 535 1234567891011121314 − + + + + + − + + + − + + + + + + + + + + + + + + + + + + + + + + + − − + + + + + − − + + + IAU name Other Coord. (1950.0) Angul. PA 0012 0942 1001 1006 1037 1114 0125 0142 0144 0214 0225 0237 0813 0847 0743 0749 0939 1123 0930 0946 1203 1205 1211 1213 1119 1152 1241 1317 1318 1323 0034 0111 1033 0143 0216 0305 0832 0916 0940 1124 0946 0225 0335 0917 0940 0741 Trinh X. Thuan et al.: HI observations of blue compact galaxies 5

Table 1. continued R N

(HI)/ & M M (compact galaxy with 1 − 1 , with no known velocity 0 − 0.440.06 8.290.31 8.52 N93 0.27 9.02 N94 8.96 N95-96* 0.29 N95 8.54 N94* 0.33 9.610.21 N94* 0.260.27 9.16 8.930.11 8.69 N93 N96 0.20 8.24 N94* 8.65 N96 N93 0.22 9.67 N93 0.25 9.47 N94 0.23 8.98 N95* 0.04 6.50 N95 0.61 7.480.36 N96* 0.34 8.58 8.17 N93 N95 0.42 9.51 N94* 0.19 9.250.26 N95 9.23 N94* 0.23 9.41 N94* 0.16 8.62 N94* 0.23 8.98 N94* 0.19 9.58 N93* 0.14 8.23 N93* 0.43 9.00 N93* 0.33 9.31 N93* 0.27 9.20 N93* ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Jy km s =62kms 20 W 1 , − 1 0.500.69 7.76 9.10 G92 G92 0.43 6.48 0.060.31 0.68 1.43 0.27 1.19 0.28 1.61 0.32 5.70 0.210.26 2.46 0.27 1.44 1.06 0.11 0.44 0.20 0.77 0.22 1.30 0.25 2.26 0.23 1.61 0.04 0.15 0.53 5.77 0.36 1.46 0.33 4.85 0.37 5.49 0.19 1.46 0.26 1.03 0.23 2.71 0.16 0.66 0.23 0.97 0.57 9.20 G92* 0.19 3.02 0.12 2.36 0.38 10.19 0.32 2.25 0.27 2.32 0.82 9.43 G92* − ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Jy km s Obs. Flux Cor. Flux Log =52kms 1 1753 1.09 1.97 04 6.27 2215 0.68 1.41 34 1.18 37 1.59 11 5.54 1131 2.43 31 1.41 1.05 62 0.44 60 0.76 10 1.29 31 2.25 18 1.58 08 0.15 06 4.98 11 1.44 05 4.73 24 4.81 13 1.45 35 1.02 36 2.68 41 0.65 13 0.96 22 2.99 44 2.97 12 2.00 05 8.89 15 2.22 42 2.30 09 8.26 50 − 20 W ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± , W 1 km s − in good agreement with our data. 1 1 1134 85 171 20 116 03 74 1409 84 84 22 148 24 211 07 179 07 211 20 95 40 137 38 169 06 158 20 190 12 116 05 42 04 53 15 146 07 134 03 74 08 158 22 200 23 169 25 157 08 206 14 190 28 327 08 158 03 218 09 187 27 201 06 203 − , about 30% higher than our flux measurement. In group: 3 Sc galaxies − 50 1 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± − W 04 Jy km s . =1 F Mpc km s = 122 km s with (20) = 156 km s 20 1 W 1 W − ) HII region at the S edge. 0617 14.9 52.0 69 132 10 50.3 74 02 11.30705 53 45.6 55.911 53 63 56.820 116 30.4 169 04 55.1 148 04 50.310 190 44.204 63 41.019 84 49.3 116 03 122.9 148 10 74.8 137 06 50.4 84 02 9.5 32 02 4.7 32 08 49.7 102 04 33.402 123 11.4 53 04 71.6 137 11 83.7 179 12 63.7 84 13 51.9 126 04 64.9 194 07 47.2 169 15 73.0 190 05 17.4 106 02 20.4 202 05 62.0 168 13 53.6 137 03 37.1 189 − 00 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± and and (HI) Dist. 1 1 V − 667 − 1855 3796 3424 2095 3545 1240 4433 = 5365 km s 0 590 0 235 0 8950 0 5485 0 4520 6075 3037 3857 60 3923 45 3409 50 2932 40 2700 60 3323 70 583 70 3367 30 609 90 5151 40 6014 90 4543 90 5460 43 1152 33 3848 40 10 65 30 15 80 30 V − − − − − − − 26 Jy km s . e e e =3 (50) = 94 km s 58 15 23 21 16 53 24 39 24 34 21 26 90 35 30 25 25 21 21 36 24 64 39 24 30 25 21 120 106 to the South with no measured velocity. F W × × × × × × × × × × × × × × × × × × × × × × × × 0 × × × × × , axb Vir 1 71 23 33 37 53 60 41 43 45 39 36 39 47 81 30 32 29 33 50 39 46 39 − 60 33 26 125 124 . 180 169 1 − to North. No velocity. 0 5/h kpc), with a very compact (7 to the South is an O or B star according to Terlevich et al. (1991). ∼ 0 67 Jy km s . ◦000 =1 to the West and 13 F s to the East and 4 s = 5677, 5653 and 5577 km s KUG 0012-018. V ≡ prefix h m s away). Keel & van Soest (1992) found that this is a “probably paired” Markarian galaxy. The possible companion galaxy is at 2.9 name or R.A. Dec. size km s CG587 14 55 32.9 44 22 37 3563 SBSSBS 492132 133119.9 SBS 592507 134145.0 CG383 552944 135848.8 14 13 18.8SBSCG470 49 34 26 593642 143003.5 MK826 14 30 53.3CG625 14 52 48 37 27.6 59 52 36 15 43 04 18.8SBS 51 26 54 MK487SBS 552530 152440.0 15 35 48.8MK1499 601129 155146.3 55 25 35 16SBS 34 07.8 52 18 563434 57 726 170703.3 with MK1479 13 32 42.6 51 52 11 MK475 14 37 03.7 37 01 13 CG328CG389 14 00 11.6 46 14 06 15 10 03.2 43 43 55 CG638 15 06 25.0 55 22 35 MK884MK1500 16 29 38.2 16MK893 20 40 31 48.3 01 51 36 17 32 14 23.0 60 16 15 CG690 15 19 16.8 49 41 34 MK812 14 22 57.8 57 21 48CG652 15 09 31.8 52 44 46 3171 MK1121 18 09 28.6 31 50 55 MK513 21 16 18.5 02 03 02 MK900 21 27 27.5 02 11 39 MK908 22 20 28.2 37 43 25 MK909 22 21 17.5 40 55 41 MK921 22 46 09.9 31 31 00 MK528MK930 23 11 34.9 23 29 29.5 12 54 19 28 40 18 2676 00 0 + + + + N + + + + + + + + + E A A V Zw 212. Possible satellite galaxy from HI spectrum at UM 219 MCG 1-5-30. Comet-like structure ( KUG 0143 + 346. Wegner et al. (1993) obtained – UM370 at 10.2 – Our unpublished VLA data show a large HI envelope around the BCG. A HST study by Thuan et al. (1996) indicates an extremely compact and dense HII region ≡ ≡ – Sc galaxy of the same brightness at 22 ≡ – Wegner et al. (1993) found ≡ 493 443 514 518 370 554 461 437 526 553 554 601 205 516 602 565 496 526 594 495 573 596 527 523 318 020 554 021 377 409 315 129 286 1234567891011121314 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + 065 018 − − IAU name Other Coord. (1950.0) Angul. PA 1331 1455 1504 1332 1437 1358 1400 1415 1430 1506 1535 1551 1629 1640 1714 1707 1519 1448 1341 1413 1422 1430 1509 1634 1809 2116 1524 2127 2220 2221 2246 2311 2329 (25)=5kpc22 d 0214+292 0111+075 0143+346 0125 in this galaxy. There is a galaxy at 10.5 Notes to Table 1: 0012 0144+024A 0142+046 within inside 30 0034+356 6 Trinh X. Thuan et al.: HI observations of blue compact galaxies

Table 1. continued , , . 1 1 ), 1 1 1 = to − − 1 − − − 0 − V 2 . to the 0 ∼ s =87kms 18 Jy km s = 110 km s . = 116 km s gree quite well. 0 = 1378 km s = 3314 km s 20 50 20 ± V W V W , W , 1 axy, containing stars ) is less than 15% of , 37 1 to the South. . − 1 1 to the South and − 00 − − 0 radius. to the South. . to the North. =0 0 1 0 00 − 3 F . , inside a radius of 30 (6 m data). 7 1 − radius with velocities equal to 1 ∼ 5Jykms − 0 =60kms to the South, . with 0 0 1 = 100 km s 50 − ± to the South, at inside a 30 = 4618 km s W 50 0 1 4 , = 104 km s . to the East, 18 V 1 W − . This may be associated with a galaxy . , s − 20 1 1 1 to the East and 30 =4 − consistent with our data. − − W 00 1 , F and 5679 km s to the West and 24 1 − 1 − 00 to the East and = 1943 km s − 00 V . 06 Jy km s ) and seen nearly edge-on. As the HI gas structure . 6Jykms to the West and 7 1 2 . =46kms 1 − and 3470 km s 0 s 1 50 ± to the North, at to the West and 6 ± 0 − = 188 km s =69kms and 3421 km s W 2 00 . 1 , 24 kpc 19 20 50 . . 1 − 1 W W − × =4 − , , =4 1 1 F ,at36 − − 0 F . . Fainter galaxy at 3 1 and 1918 km s , 3360 km s 1 − 1 1 − − − /50). Detailed studies with the HST (Thuan et al. 1997; Thuan & Izotov . 17 Jy km s . In group with the companion galaxy MCG 9-22-48, located at 3 1 . This HI component may be associated with a brighter galaxy at .

1 1 − (25)=1 0 Z = 4350 km s 8Jykms − − . a to the East and 1.5 = 130 km s 0 to the South. Its velocity is about 27000 km s V ± s to the North. In group: 2 galaxies inside of 30 0 50 ± 0 and Theureau et al. (1998) obtained =32kms = 180 km s . W 1 43 1 . 50 V − − 23 . to the South, or a faint galaxy at 8 W and =0 0 =70kms , 4 1 radius at to the South, or with a very faint fuzz at 10 1 =1 F − 0 50 0 − and 1808 km s ∼ with ∆ radius at velocities 3128 km s F 6 1 W 0 0 MK251, at 20 − , ∼ 1 25 with = 127 km s ≡ − 1 = 1785 km s ∼ 20 − V to the West and 1.5 W to the SW with unknown velocity. 07 Jy km s , 02 Jy km s . s . 0 1 8totheEastand14 0 . s − radius at velocities of 2001 km s =2 ± 0 11 Jy km s to the East and . F 0 0 15 1 . to the East and 75/h kpc in projection). = 1955 km s 0 ± ∼ =0 ∼ V ( CP 384ab. = 105 km s to the SE with 24 F to the South, with no known velocity. Background HI emission at 1 . 0 ≡ 50 0 to the West. A correction factor of 1.27 has been taken into account for the integrated flux density. With this offset, − 100/h kpc in projection). The BCG is at the outskirts of a medium density group GH 47 (Garcia 1993). , yielding no confusion, with SBS 1317+523B, and with SBS 1318+520 at 25 s W =0 1 , with ∼ − 1 ( F 1 − , 1 − 1 − VV 828 103. − 9 kpc) galaxy seen edge-on. Schneider et al. (1992) obtained 8) about 6 − ≡ radius with velocities of 1772 km s . ). In group. 3 galaxies with velocities equal to 3526 km s m ∼ to the North. In the same group with 2 SB galaxies with velocities of 5641 km s 40 km s 1 0 = 1009 km s 0 − ± V =12 53 Jy km s . 103. Galaxy 1 mag fainter at 5 B to the West and 18 − IZw64 = 4602 km s s =4 = 4155 km s = 5339 km s ≡ V MCG 9-25-23. In group. 2 Sc galaxies inside 30 F /41, this is the most metal-deficient BCG known after I Zw 18 ( V = 4444 V =86kms

radius at ≡ CGCG 274-13. Sc galaxy UGC 9702 at 8 Z V 0 50 ≡ W KUG 0225 VV 654, pair? In group? Sb galaxy NGC 2446 at , 1 to the East and 17 KUG 0946+588, spiral, Thuan & Martin (1981) obtained ≡ ≡ − UGC 5188. Haynes et al. (1988) obtained UGC 8565 MCG 11-14-25. Dwarf Irr disk with 2 bright knots. Thuan & Martin (1981) obtained s MCG 9-17-18, Dwarf ( 104. In group with 0225 ≡ ≡ ≡ ≡ UGCA 166. The most metal-deficient BCG known (1/50 of solar metallicity) and a young galaxy (stars not older than 100 Myr, Izotov & Thuan 1998). − ≡ ≡ to the North, or with a fainter galaxy at 0.2 to the North. In group. Two SBc galaxies inside 30 0 3totheWestat in good agreement with our data. . s 7 0 . 1 . It may come from either a pair of galaxies at 1 1 − 14 Jy km s . . − KUG 1504+514 KUG 1430+526. MCG 9-22-47. Observation was made at 13 1 ∼ 0 to the South, with KUG 1509+527. Paired with Sdm galaxy MCG 9-25-31, 0.4 mag brighter and with MCG -2-7-10 UGC 5179. Spiral galaxy seen almost face-on. The bright SO galaxy NGC 2950 is 3.5 mag brighter at 25.3 KUG 1006+578. Sc galaxy UGC 9737 MCG 9-13-55 MCG 10-13-25. Compact galaxy with a bright nucleus and two tails. KUG 0942+573. NGC 5238 NGC 2909 KUG 0225 KUG 0940+544. KUG 0940+543, 1 mag brighter galaxy at 10 MCG 9-22-51. In group with SBS 1317+523A and B and MCG 9-22-48 (see theKUG note 1422+573. for Spheroid SBS with 1317+523A). 2 tails along major axis. KUG 0917+527. KUG 0946+487. MCG 10-18-13. Spiral seen almost face-on. In group? NGC 4195 inside 30 UGCA 184 IZw18 − UGC 6448 . UGC 5421 00 ≡ ≡ ≡ – Edge-on spiral NGC 5422 ( 1 ± ≡ ≡ – Edge-on Spiral. There is also a HI component at ≡ – Possible HI satellite at ≡ ≡ ≡ ≡ ≡ ≡ – Galaxy at 7.2 ≡ ≡ ≡ ≡ ≡ – One of the smallest objects in our sample. – In group? Two galaxies inside a 30 ≡ ≡ – Foreground HI source at ≡ ≡ ≡ – With a metallicity of ≡ ≡ – Galaxy 2 mag brighter, 11.4 − 34 . 568 644 578 553 527 550 612 573 518 103 662 535 104 544 555 586 523A 520 573 526A 514N 540 587 527 487 052 483 596 597 554 558 592 554E = 119 km s =36kms + + + + + + + + + − + + − + + + + + + + + + + + + − + + + + + + + 30/h kpc in projection). =0 20 50 ∼ F East and 30 0749 Haynes & Giovanelli (1991) obtained W W 1123 In group? UGC 6390 inside of 30 the integrated flux density contribution of the nearby galaxy SBS 1317+523B ( 1006 4740 km s 1506 1509 in 2100 km s 0743 0847 0942 the measured integrated flux density of SBS 1317+523A, which is, after subtraction, of 4.2 Jy km s 1332 NotestoTable1(continued): and 1 mag fainter0225 than SBS 0214+292. ( 0940 ( 0741 is not well approximated by our adopted model of a gaussian disk, the beam correction is somewhat uncertain. However the single-dish and VLA HI masses a NGC 1376 is at 37 2 mag fainter at 4 0225 1997), MMT (Izotov etnot al. older 1997), than Russian 100 6 Myr. m (Pustilnik A et VLA al. map 1997) (Pustilnik and et Keck al. (Lipovetsky 1999) et al. shows 1999a) that telescopes the suggest HI that envelope this is galaxythe unusually is West large a and (64 young gal 0940 1001 1119 1317 1318 1422 1430 1504 1211 1114 0917 0946 0335 1323 1430 1213 0930 0946 0939 1358 Trinh X. Thuan et al.: HI observations of blue compact galaxies 7

Table 1. continued 1 − =28kms to South. 50 0 5 W . , 1 1 ∼ − 11 Jy km s . 0 ± , with no known velocity and, 2.2 with mag no known velocity and 1.8 mag 0 0 to the South. 16 0 . 6 ∼ =0 F , , in good agreement with our data. 1 1 − − in good agreement with our data. 1 − . It may correspond to faint galaxy at 1 to the East and − 00 = 131 km s = 2516 km s 20 V = 189 km s W , 20 1 − 12 Jy km s W . 0 and ± 1 − 36 . = 121 km s =0 50 F W , 1 , 60% higher than our flux. = 202 km s and − 1 − 1 50 − W , 1 − 97 Jy km s . = 206 km s (Schneider et al. 1992). In group? =1 20 = 6070 km s 1 . Possible faint foreground HI emission at − F W V 1 , 78 Jy km s − . 1 − =8 to the South, or to a faint galaxy with bright knots 76 F 0 to the South, with unknown velocities. 0 = 4130 km s V 37 Jy km s . =3 with 0 F 10 ∼ to the West and 23 s Arakelian 549. Lewis (1987) obtained ≡ UGC 12009. Wegner et al. (1993) obtained NGC 7077 UGC 12434. – The HI and optical velocities differ by 300 km s Keel & van Soest (1992) found that this is a “probably paired” Markarian galaxy. The possible companion galaxy is at 2.2 Keel & van Soest (1992) found that this is a “probably paired” Markarian galaxy. The possible companion galaxy is at 0.3 – There is a second component of the HI profile with ≡ – Sm galaxy UGC 12027 at ≡ – Jackson et al.≡ (1987) obtained – Two galaxies at 3.7 602 377 409 020 021 315 129 496 601A 318 + + + + + + + + + + 1714 2220 2221 fainter than SBS 1809+318. 2116 fainter than SBS 2116+020. 2127 2246 2311 NotestoTable1(continued): 1519 which could be associated either to a faint galaxy at 3.3 1551 1809 8 Trinh X. Thuan et al.: HI observations of blue compact galaxies

Table 2. Uncertain and confused HI detections R N

(HI)/ & M M 1 − 0.26 8.41 N94* 0.380.54 9.300.20 9.330.21 N93* 9.13 G93* 7.88 N93* N93* 0.850.580.39 9.550.42 9.410.39 8.33 G92* 8.97 N93* 8.32 N94* N93* N93* 0.180.16 8.89 8.360.21 N94* N94* 0.36 9.16 9.60 N93* 0.28 N94* 7.64 N93* 0.230.24 9.030.45 8.82 N93* 9.68 N94* N93* 0.38 8.950.27 N93* 9.86 N93* 0.260.08 8.560.23 6.05 N94* 8.83 N94* N95* 0.21 8.49 N94* 0.56 8.400.32 N93* 8.060.32 N96* 8.61 N94* 0.30 9.19 N93* 0.250.32 6.78 8.77 N94* N94* 0.13 8.48 N94* 0.19 8.14 N93* 0.30 9.24 N94* 0.73 9.43 N94* 0.26 9.20 N94* 0.42 9.92 N93* 0.39 9.26 N96* 0.20 8.55 N94* ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Jy km s 1 − 0.26 0.39 0.370.53 2.41 2.59 0.200.21 0.57 0.85 0.59 0.800.57 21.74 9.360.39 4.21 0.42 0.85 G92* 0.39 2.78 1.80 0.180.16 0.76 0.16 0.21 1.35 0.360.85 3.90 0.28 0.84 9.43 G91* 1.360.23 0.63 0.24 1.13 0.45 10.28 2.72 G92* 0.38 4.66 0.270.92 1.42 9.92 G92* 0.26 0.90 0.080.23 0.12 0.47 0.21 0.55 0.55 5.34 0.32 0.53 0.320.43 1.96 8.82 G91* 0.29 0.86 0.41 9.09 G92* 0.25 0.37 0.32 0.47 0.13 0.26 0.19 0.52 0.27 1.59 0.69 7.76 0.26 1.47 0.41 2.93 0.90 9.86 G92* 0.35 4.53 0.19 0.72 2.06 9.42 G92* ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Jy km s Obs. Flux Cor. Flux Log 1 4032 2.33 2.53 8297 0.56 43 0.58 5.25 0526 21.62 27 4.18 36 0.85 23 2.75 1.79 26 0.75 37 1.33 4931 3.85 10.25 52 0.83 33 23.60 66 0.63 38 1.13 21 2.70 15 4.63 5438 1.41 5.55 20 0.90 2334 0.12 0.47 80 0.55 07 5.26 21 0.52 0019 1.95 3.16 44 0.84 15 0.70 24 0.37 18 0.47 17 0.25 53 0.52 59 1.45 13 7.32 12 1.46 72 2.87 17 4.65 20 4.12 20 4.01 − 192 0.39 178 0.16 101 0.71 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± 20 ± ± ± W km s 1 2620 206 175 5262 190 28 158 10 152 14 50 22 42 04 95 17 119 17 305 23 124 15 148 169 17 115 0423 84 13 106 3120 53 228 00 218 1233 84 96 102 21 337 42 112 24 139 13 222 1611 48 42 1110 74 186 3424 238 253 34 95 51 116 08 85 28 130 09 100 38 159 08 160 46 253 11 244 13 257 65 148 13 294 − 123 196 129 129 50 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± W Mpc km s 1 1310 59.2 59.1 144 148 1430 43.0 43.107 84 30 6.308 32 09 51.011 32.507 278 38.1 110 22.2 84 148 09 65.602 88 14.112 67 67.21610 63 65.8 33.509 131 17 136 29.7 14.961 55 48 53.1 42 2631 100.0 23.4 148 87 11 78.402 74 26.3 89 57 78.1 40 07 30.306 42 29.6 42 11 58.521 239 84.412 34 49.507 100 86.6 201 0806 8.3 73.2 35 32 05 69.805 63 28.617 144 12 146.9 79.4 183 210 17 33.7 42 25 49.0 42 04 67.5 67 14 87.505 88 86.7 93 19 68.1 74 04 38.2 136 23 110.0 142 06 80.8 232 06 43.432 223 45.6 53 07 52.9 286 − ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± (HI) Dist. V 7261 1375 5602 1566 5704 1848 1801 4958 6269 4797 2480 8048 5796 2870 3649 0 4368 0 6230 0 3793 0 6617 0 4424 0 5195 90 5151 10 2177 6510 10844 5720 90 2160 40 3351 50 45 40 15 50 70 15 30 20 45 10 45 28 60 33 − − − − − − − − − − − − − − − e e e e e e e e e e e e e e 3026 6028 90 4150 27 4050 5229 9022 0 2885 25 2838 018 21 289 1422 4523 0 3481 20 2032 0 2488 1257 2511 34 70 4610 33 7523 26 45 706 32 4757 24 9036 39 4618 25 2097 6018 45 1797 52 777 3645 31 45 6340 39 77 32 17 83 22 55 3075 24 20 61 55 16 13 22 22 20 23 25 66 20 22 18 × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × × axb Vir 27 19 48 42 11 25 01 05 26 ◦000 05 05 08 − − − prefix h m s name or R.A. Dec. size km s MK365 02 01 26.0 28 24 57SBS 70 075629.3 610725MK19 20 SBSSBS 09 12SBS 53.5 092620.1 604002SBS 101131.5 43 600607U6074 59 16 102855.3 58 53 563706MK1445 105402.7 35 502428 10 11 42 57 65 SBS 14 02.7 42.7SBS 51 51 112323.2 10 42 14 573742 16SBS 112516.8 24 561303SBS 33 78 SBS 41 112915.5 573917SBS 113626.3 65 604722SBS 113748.4 29 585510SBS 114421.9 20 590950SBS 114716.4 28 520051 114955.9 28 593937SBS 30 115931.8 514018SBS 22 SBS 121655.5 550813SBS 20 122119.8 583123 122158.6 38 543124SBS 122244.5 15 612545SBS 38 MK251 124220.2 545951SBS 131454.1 41 603420MK1480 13 17 56.3 45 MK1481 131928.4 13 575736CG337 40 56.0 13 83 52 41 18 03.6 47CG707 14 52 01 57 50.0 35 52 35 56 22 15 23 51.6 49 35 00 18 48 51 55 22 42 36 + + ∗ ∗ + + + ∗ ∗ ∗ ∗ ∗ ∗ ∗ ∗ ∗ ∗ ∗ + + ∗ + + + + + + + ∗ + + ∗ + + + + + + + + 307A KUG 01 27 53.6 30 43 29 33 081 MK552 00 28 43.9 08 11 59 103 611 517 529 284 054 MK604591B SBS 03 10 18.4 07 43 32.2 59 07 52 64 057A SBS587 03 35 SBS 44.6 606AB 07 55 42.8601 58504 45 12511A 83 562 607 589 591 520 596 516B 545B 614 554C SBS605 579AB 12 40 36.6490 55 25 09439 139 CG564 14 50 09.8 43 55 27 100 579A SBS 08 14 08.9 57 54 51 53 460 MK1471585 12 16 10.8 46 03 45 30 080 MK1023 02 07 20.6 566 5145 U6309524 11 14 57.0 SBS 51 45 17 11 25 50.8 105 52 27 21 44 523B 529 328 KUG 01 36 20.8603AB SBS 32 51 52 27 07 50 53.7 60 19 10 30 549 519 551 703 MK95 08 44 33.4 70 20 53 49 576 576 599 1234567891011121314 + + + + + + − + − + + + + + + + + + + + + + + + + + + + + + + − + + + + + + + + + + + + + + IAU name Other Coord. (1950.0) Angul. PA 0127 0028 0756 1114 1340 0201 0310 0743 0335 0755 0926 1011 1054 1057 1125 1136 1137 1144 1147 1149 1159 1221 1222 1240 1314 1319 1401 1450 0814 1216 1221 0207 1028 1114 1125 1317 1341 0136 0750 1242 1523 1216 0844 1123 1129 0912 Trinh X. Thuan et al.: HI observations of blue compact galaxies 9

Table 2. continued , 1 − and 1 to the R N − 0 to the South , DEC(1950) s 00 = 220 km s

(NGC 4953) = , DEC(1950) = (HI)/ & s M 50 F 20.1 M . W m = 4573 km s 0 in the NS direction, . 23.0 0 1 26 V m h − 1 at 8 26 − h 1 0.560.282.39 9.450.25 9.34 10.02 N93* 0.11 8.94 N93* N94* 0.10 8.36 N94* 8.45 N94* N93* 0.20 8.65 N93* 0.25 9.09 N95* to the East and 5.7 larger (6 m data). Physical − s 1 ± ± ± ± ± ± ± ± to the West, 63 − s (17/h kpc in projection). Jy km s 35 Jy km s 1 . to the West. − s =4 100 km s F 1 to the North with = 3826 km s − 0 ± 0.25 1.20 0.550.28 4.96 2.36 1.44 13.52 0.11 0.20 0.10 0.17 0.20 0.45 0.25 1.40 V and ± ± ± ± ± ± ± ± 1 = 2209 km s − in the EW direction and 3 ? No beam correction was made. 1 Jy km s s V Obs. Flux Cor. Flux Log − KUG 0755+588) at 17 ≡ 1 63 1.20 3048 4.89 25 1.43 13.13 17 0.20 15 0.16 40 0.45 42 1.40 − = 2876 km s 20 ± ± ± ± ± ± ± ± to the East and 9.3 W V in the SN direction, corresponding to 14/h kpc in projection. 04; For 0926+606B (RA(1950) = 09 km s s = 3836 km s . 0 and NGC 2650 at V 0 to the North with . 1 96. 0 1 . 40 196 1930 202 16 153 301 11 53 10 63 26 87 27 211 − − at 5.1 (HI)=9 to the South. 50 to the North, and faint galaxy at 5.1 ± ± ± ± ± ± ± ± 0 1 M 0 W in the SN direction, corresponding to a projected distance of 24/h kpc. Not − 00 (HI) = 8 to the South, with a velocity of 230 to the North, with no known velocity. 0 to the North with 0 M 0 to the North, at 0 = 6420 km s ,andlog 1 Mpc km s V − . 1 . to the East and 2.7 = 3626 km s − 1 to the East, 1.1 ,andlog s − to the East and 8 1 s 1 V 20 55.3 137 0915 49.008 79.8 152 58.3 91 05 283 69.705 42 84.0 53 13 64.6 63 13 60.9 158 − s − ± ± ± ± ± ± ± ± 37 km s ,2.2 to the North; unknown velocity. in the EW direction and by 1.2 (HI) Dist. to the West, 4.3 1 0 ± s to the North, with no known velocity. s V − to the West and 6 to the East and 3 2Jykms 0 . 3310 5687 4027 5530 6202 s to the North, s 37 km s to the East and 1 00 s =2 = 4335 km s ± in the EW direction and 32 = 120 0 4794 brighter, at 1.1 F V s 60 50 45 42 20 20 m − − − − − W = 120 = 7918 km s , 1 20 V e − W 22 19 22 1412 3860 4004 11 90 4218 25 , to the East and 4.1 to the East and 4 × × × × × × 1 × × axb Vir s 40/h kpc in projection. s − ∼ to the East and 16 , separated by 3 23 km s s 1 to the South with − ± 00 23 km s ± ◦000 . =78 1 − 200 km s 50 =67 (Mebold et al. 1979), in good agreement with our data. W ∼ 1 , 50 V 1 − W − , 1 − to the East and 27 = 4764 km s s . V 1 080. Confusion by E-S0054. galaxy Confusion? NGC S0 842 galaxy at NGC 1.3 1248, 2.5 = 241 km s − − − 50 with W 0 – Pair of BCGs of similar brightnesses, separated by 2.5 (Haynes & Giovanelli 1991). Pair? . We have modeled the two peak HI-profile to derive parameters for each component of the pair. For 0926+606A (RA(1950) = 09 1 prefix h m s 1 (HI) = 4090 km s − name or R.A. Dec. size km s − and V SBSIZw116SBS 572704 153303.3 SBS 40 15 33 23.9 572319 154241.1 SBS 82 46 513054 155540.2 58MK1129 48 17 MK317 575238 163240.8 35 23 24 04 09.7 23 11 20.7 09 44 02 23 32 54 25 90 UGC 6074. Sdm galaxy MCG 9-18-67, 1.3 mag fainter, at 2.8 1 UGC 6309, not a BCG. See the note for SBS 1114+5145. (HI) = 4002 km s –PairofBCGswith∆ KUG 0844+703. In group. Confused by Sm galaxy UGC 4593 at MCG 10-12-47. Flux corrected by 25% due to a large offset in the pointing. Confusion with MCG 10-12-51 ( KUG 0201+284. No confusion. Uncertain parameters. In group with the SO galaxy NGC 805 at 11 KUG 0207 KUG 0310 Holmberg 11. Confusion. The BCG is a member of the Hickson compact group No. 2B (Hickson 1982). Three galaxies in beam. The nearest one is UGC 312, an Sc − = 5760 km s ∗ ), ∗ V ≡ – Confusion? Scd galaxy PGC 13407, 4 mag brighter, no velocity, at 6 – Confusion? galaxy 0.5 mag brighter, at 2.3 – Confusion with the BCG SBS 0814+579B with – Confusion. Irr galaxy 14.7 mag at 11.4 ≡ 00 ∗ + + ∗ ∗ + ≡ – Flux corrected by 42% due to offset of pointing relative to correct position. Possible confusion by Sc galaxy MCG 9-19-82 at 22.6 – Paired with another BCG (SBS 1011+600) which is also included in the statistical sample. The separation is 1.0 ≡ ≡ – No confusion. Uncertain parameters. – Confusion? Scd galaxy KUG 0136+329, 0.5 mag fainter, at 3.6 ≡ – Possible confusion with MCG 9-19-85, at 9.5 ≡ – Interacting galaxies in contact. – No confusion. Uncertain parameters. – No confusion. Uncertain parameters. – No confusion. Uncertain parameters. ≡ – Confusion with Sb galaxy UGC 6309, 2.7 mag brighter, at 14.4 V ), 02 00 0 235 469 573B 515 585 SBS097 15 58 54.8 58 31 11 13 578 100 km s from telescope position). No known . 15 1234567891011121314 566 328 524 080 054 057A 591B 703 307A 517 081 599 587 601 284 603AB 611 504 5145 576 606 A and B 579A 511A 562 40 + + + + + + + 0 ◦ s = 264 km s ∼ + + + − − − + + + + + + + + + + + + + + + + + + 41 ◦ 20 V IAU name Other Coord. (1950.0) Angul. PA 1533+574 2311 1533 1542 1555 1558 2304 1632 North, at =60 corresponding to 20/h kpc1028 in projection. The pair is not resolved by the single-dish beam. W 0136 ∆ 1125 0207 with NGC 807 at 21 0310 (13.1 0335 0743 0844 0127 1114 Notes to Table 2: 0028 0912 resolved by the single-dish0755 telescope beam. 1011 0201 0750 0756 60 pair (45 kpc/h in projection). Armstrong & Wooten (1986) obtained 1054 4.66 Jy km s 1114 1123 galaxy 0.7 mag brighter at 5 0926 0814 1057 1125 10 Trinh X. Thuan et al.: HI observations of blue compact galaxies

Table 2. continued , 1 = − V )and to the to the 1 0 0 − (UGC 9569) F = 279 km s 50 W = 4619 km s , 1 V − to the North. No known to the West and 2 0 to the West and 2.7 s s to the West. 9Jykms s . and galaxy MCG+10-22-36 inside 1 . Sc galaxy MCG 10-22-21, 0.5 mag 30/h kpc in projection). Interaction? . 1 − 1 =10 . The Green Bank flux of the pair is a − ∼ 1 − F − .( . Pair? (15/h kpc in projection). 1 , 1 1 − . In group: 5 galaxies of similar brightnesses − − to the East and 7 . No confusion. 1 1 to the North. No velocity. In group: 3 bright s − − 0 78 km s . In a group with SBS 1317+523A, MCG 9-22-48 = 3957 km s 5kms 1 ± − V ± = 25440 km s (6 m data). In group or pair? UGC 6732 with 1 48 km s V ). − = 1296 km s 1 ± (Bottinelli et al. 1999). − = 4764 km s V = 1880 1 = 2504 V − 7Jykms (HI) = 3465 km s V . V V =3 . = 1847 3500 km s 1 to the North, and has the same HI velocity ( F − 0 V to the West and 11.5 ∼ to the North (26/h kpc in projection). Parameters are given for the ), 2 mag brighter, at 1.1 = 3129 km s to the South and with unknown velocity. Pair? s 00 0 V 0 to the North, V = 4835 km s 0 to the South, with to the South with no known velocity. 0 V 0 to the South, and a slightly brighter galaxy at 4.5 )at7.8 to the West with 0 00 (25) = 1 s = 1253 km s to the South with to the South, with a 0 to the North, with 0 V to the North. No confusion. 0 =30 00 a . We have attempted a decomposition to estimate fluxes for each galaxy: to the North, with to the West and 1.5 1 to the South, at 0 s to the East, 3.8 (see the note for SBS 1317+523A, in Table 1). − to the East and 17 0 s 1 ) and NGC 3895 ( s 1 − to the West and 2 − . Sc galaxy ( 1 s to the North, with to the West and 9.5 − 0 s to the North. Unknown velocity. 0 to the East and 2 = 183 km s feature may be due to some faint radio interference, or may be associated with a brighter galaxy at to the West and 4.3 to the North with to the East and 1.2 s 0 s 1 s 50 − to the West and 18 = 4740 km s W s = 3242 km s , V = 200 km s 1 V to the West and 1.2 to the West and 9 − s V s )at13.5 00 radius. . 1 0 to the East and 11 − . s = 4900 km s 1 to the North. Uncertain parameters. − V to the East and 7 0 = 154 km s 5 (25)=60 s . a inside 30 50 1 ∼ 1 − W − to the South, with , 1.0 Jy km s 0 1 radius: NGC 3894 ( cay. No confusion. − 0 ± MCG 10-23-15), 2 mag brighter, at 16.5 ≡ = 3706 km s 0Jykms to the North. No known velocity. . 0 V =10 . Possible confusion with MCG 10-19-63 at 12 to the East and 17 1 F − s (UGC 9567) = 5.9 to the North. 0 F 80/h kpc in projection). , 1 ∼ ( − (Haynes & Giovanelli 1991). Pair? (28/h kpc in projection). Also a close companion, a galaxy of the same brightness at 4.1 0 radius with velocities near 4500 km s 1 0 NGC 5113, edge-on Sbc with two HII regions at the ends (A and B). Confusion with Sc galaxy NGC 5109 1.7 mag brighter at 29 − to the West and 4 UGC 7887. Confusion with SBb galaxy of the same brightness (NGC 4644) at 12 s UGC 10002. SBc galaxy. Interacting system with the BCG 1542+573A. In group. Sc galaxy UGC 10022 with MCG 9-22-49. Confusion with the BCG SBS 1317+523A, which is at 20 = 2131 km s ≡ VII Zw 611. Confusion? Pair or two components in the process of merging? Difference in optical velocities is about 150 km s UGC 9569. Confusion with UGC 9567 ( ,at14 ≡ – Possible confusion by faint galaxy at – No confusion. Uncertain parameters. ≡ ≡ V 1 – Confusion? Large difference between optical and HI velocities. Sc galaxy ( No confusion. MCG 10-17-56, 1.2 mag brighter, at 8 – Pair with SBS 1559+585 ( – No confusion. Uncertain parameters. The – Confusion? Optical and radio velocities differ by ∆ – Confusion? There are another compact galaxy of about the same brightness at 1.6 – Elongated edge-on spiral galaxy. Possible confusion with low-surface brightness galaxy at 1 – No confusion. In group. Inside 30 – Confusion with the S galaxy NGC 4669, at 10 – Paired with MK 1481, a BCG which is 0.5 mag fainter, at 8 – No confusion. Uncertain parameters. – Uncertain parameters. No confusion. Galaxy 0.5 mag fainter at 15.5 – Confusion with a close Irr galaxy (MCG 10-17-10) 1.7 mag brighter, 1.3 – No confusion. Uncertain parameters. – Paired with MK 1480, a BCG 0.5 mag brighter, at 8 – No confusion. Uncertain parameters. – No confusion, uncertain parameters. – Pair or interacting system, Galaxy 1.5 mag fainter at 2.2 – No confusion. Uncertain parameters. – Confusion with the Sc UGC 6802 at 13.9 – Confusion? Sab galaxy of similar brightness (MCG 10-18-43) at 8 ≡ – Confusion with Sc galaxy UGC 6619, 2.6 mag brighter, at 19 ≡ radius with velocities around 4800 km s − 0.8 Jy km s 0 to the East and 3 ± 591 460 596 554C 549 529 578 097 589 573B 516B 579AB 576 551 529 607 545B 605 519 469 515 585 490 439 235 520 585 614 523B 574 0 = 327 km s + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + 9 radius. The flux is highly uncertain due to a large correction for pointing offset. . 0 0 50 W 1144 2285 km s South with 1216 1149 1240 inside 30 1242 and SBS 1318+520 at 11.4 1340 brighter, at 12 decomposed profile. 1632 2304 1137 HI line widths. After subtraction of the integrated flux density contribution from SBS 1317+523A, we find 1542 =4.9 1159 galaxies inside 30 1319 NotestoTable2(continued): 1129 1216 Schneider et al. (1992) give velocity. In group? Sab galaxy at 1341 1136 factor of 1.6 larger than that measured at Nan¸ 30 1221 1314 1523 1533 ∼ 1555 1558 1401 North. Unknown velocities. 1450 2311 1147 1221 1222 1317 1533 Trinh X. Thuan et al.: HI observations of blue compact galaxies 11

Table 3. HI non-detections of BCGs IAU name Other Coord. (1950.0) V (opt) RMS Run 1 name or R.A. Dec. km s− mJy Note prefix 1234567 0109 019 MK563 01 09 16.9 01 55 15 4900 2.0 N94 0155− + 021 MK1169 01 55 03.9− 02 10 50 4950 5.8 N93* 0200 + 023 MK585 02 00 55.2 02 19 35 6400 6.3 G92* 0223 + 009 MK1038 02 23 53.9 00 56 11 1500 1.7 N94* 0323 003 MK611 03 23 40.9 00 22 39 9095 5.7 G92* 0333 − 048 MK613 03 33 57.6 −04 51 56 6490 7.5 G92 0715− + 594 SBS 07 15 19.0− 59 26 55 2400 2.1 N94* 0745 + 587 SBS 07 45 24.6 58 47 11 6370 2.9 N93* 0749 + 582 SBS 07 49 42.0 58 16 00 9424 1.9 N93 0807 + 580B SBS 08 08 04.3 58 03 25 7980 6.4 G92 0810 + 583 SBS 08 10 11.2 58 21 04 7786 6.0 G92 0907 + 593 SBS 09 07 15.9 59 18 12 8894 8.4 G92 0911 + 472 SBS 09 11 13.1 47 14 28 8130 5.3 G92 0943 + 543+ SBS 09 43 40.8 54 19 33 1660 5.0 G92* 0948 + 532 SBS 09 48 16.7 53 13 00 13960 2.8 N95 1030 + 583+ MK1434 10 30 56.3 58 19 20 2400 2.7 N94* 1057 + 511B+ SBS 10 57 10.5 51 07 22 3060 7.3 G92 1118 + 578B SBS 11 18 39.1 57 53 30 2163 3.8 N93 1122 + 575+ SBS 11 22 12.8 57 32 37 1200 1.7 N94 1128 + 573+ SBS 11 28 28.9 57 20 33 1480 6.5 G92 1135 + 581+ MK1450 11 35 51.3 58 09 24 900 2.8 G92, N93* 1137 + 589+ SBS 11 37 48.3 58 55 10 1850 4.6 N94 1159 + 545+ SBS 11 59 29.0 54 32 32 3600 2.8 N94 1212 + 493+ SBS 12 12 06.0 49 23 18 3800 6.7 N92 1222 + 588+ SBS 12 22 29.1 58 49 17 4722 3.0 N93 1307 + 563+ SBS 13 07 41.5 56 18 21 5200 2.1 N94 1354 + 597B SBS 13 54 02.1 59 42 17 3000 5.3 G92 1420 + 544 CG413 14 20 59.1 54 27 42 6280 5.7 G91 1423 + 518+ CG424 14 23 41.1 51 46 36 2140 7.6 G92 1446 + 595+ SBS 14 46 20.6 59 34 20 2120 7.0 G92 1453 + 526+ CG577 14 53 09.0 52 37 54 3280 7.5 G92 1459 + 483 CG608 14 59 44.2 48 18 12 3100 8.2 G92 1503 + 531+ CG618 15 03 02.0 53 06 54 5500 3.0 N94* 1614 + 600 SBS 16 14 51.9 60 02 59 9100 2.5 N93* 1620 + 577+ SBS 16 20 15.5 57 44 45 5600 2.0 N94 1716 + 302 MK894 17 16 32.4 30 14 06 4400 2.5 N96 2325 024 MK1131 23 25 27.0 02 26 24 2580 7.2 G92 − − Notes to Table 3: 1 All optical velocities have been obtained with the 6m telescope IPCS with a typical accuracy of 100 150 km s− .Theycome either from Stepanian et al. 1993 (a-d), or Lipovetsky et al.’s unpublished catalog of BCGs. − 0155+021 UM 151 0200+023 ≡ UM 391 0223+009 ≡ IC 0225 0323 003 ≡ KUG 0323-003 0715+−594 ≡ UGC 3789 0745+587 ≡ KUG 0745+587 0943+543 ≡ KUG 0943+543 1030+583 ≡ KUG 1030+583 1135+581 ≡– Observed in the G92 and N93 runs, with F (peak) = 22 4.1 mJy, and 5.4 2.8 mJy respectively. In both cases 1 1 ± ± V 950 km s− as compared to V (opt) = 896 21 km s− . This HI emission may come from a galaxy with similar brightness ∼ s ± at 14 to the East and 4500 to the South, which is entirely in the beam of the 140 ft telescope but only partially in the beam of the Nan¸cay telescope. 1503+531 – Elongated edge-on S galaxy. Uncertain parameters. s 1614+600 – Confusion? Sc galaxy, 3 mag brighter. At 16.5 to the West and 1.80 to the North. No known velocity. 12 Trinh X. Thuan et al.: HI observations of blue compact galaxies

Fig. 1. HI profiles of the 79 certain BCG detections (Table 1). The ordinate is line flux density in mJy and the abscissa is 1 heliocentric velocity in km s− Trinh X. Thuan et al.: HI observations of blue compact galaxies 13

Fig. 1. continued 14 Trinh X. Thuan et al.: HI observations of blue compact galaxies

Fig. 1. continued Trinh X. Thuan et al.: HI observations of blue compact galaxies 15

Fig. 1. continued 16 Trinh X. Thuan et al.: HI observations of blue compact galaxies

Fig. 1. continued Trinh X. Thuan et al.: HI observations of blue compact galaxies 17

Fig. 2. HI profiles of the 53 less secure or confused BCG detections (Table 2). The ordinate is line flux density in mJy and the 1 abscissa is heliocentric velocity in km s− 18 Trinh X. Thuan et al.: HI observations of blue compact galaxies

Fig. 2. continued Trinh X. Thuan et al.: HI observations of blue compact galaxies 19

Fig. 2. continued 20 Trinh X. Thuan et al.: HI observations of blue compact galaxies

Column (5). Holmberg (H) major and minor diame- ters in arcsec to the limiting surface brightness of B = 2 26.5 mag arcsec− , derived mainly from CCD surface pho- tometry (Lipovetsky et al. 1999b; Kniazev 1995). When CCD data was not available, Holmberg diameters were derived from measurements on the Palomar Sky Survey (PSS) blue prints and the relation obtained by least- square fitting to the diameter data from a subsample of 48 of our BCGs with CCD photometry:

dH (arcsec) = 2.53dPSS (arcsec) + 7.400. Diameters derived in this way are marked by the letter e. They are less accurate than the CCD diameters and serve only to correct the HI fluxes for beam effects (Col. 12). We are in the process of deriving accurate CCD diame- ters for all BCGs in the statistical sample. Diameters are given only for BCGs observed at Nan¸cay, which require a beam-flux correction (see Col. 12). Column (6). Position angle in degrees of the major axis of the galaxy measured eastward from north. 1 Column (7). Heliocentric HI velocity in km s− deter- mined as the midpoint between the half-peak points on both sides of the HI profile. The velocity error is esti- mated from the peak signal-to-noise ratio as decribed by Schneider et al. (1986), and includes an estimate of errors based on the slope of the profile edges. It is calculated as: 1 ∆V =1.5(W20 W50)(S/N)− − where S/N is the ratio of the peak signal to the rms noise. Column (8). Distance D in Mpc to the galaxy. We have used the Virgocentric flow model described by Kraan- Korteweg (1986) with a Virgocentric infall motion of 1 1 1 220 km s− and a Hubble constant of 75 km s− Mpc− . 1 Columns (9) and (10). Velocity widths in km s− of the HI profile at 50% and 20% of peak. Again, errors are calculated following Schneider et al. (1986) and are based on the same method as for the velocities in Col. (7). The expected error for the 50% width is 1 3.0(W20 W50)(S/N)− and − for the 20% width is 1 4.7(W20 W50)(S/N)− . − Column (11). Observed integrated flux density in 1 Jy km s− . Following Schneider et al. (1990), we assume that the window over which the flux was measured is 20% wider than the velocity width measured at 20% of peak. The statistical error on the flux is then: 1/2 σ =2(1.2W20/∆V ) ∆VσV where ∆V is the velocity resolution of the smoothed data, and σV is the rms dispersion in the baseline measured at that resolution. The factor of 2 accounts for baseline uncertainties. Column (12). HI flux densities corrected for telescope beam size. This correction is negligible for observations made with the NRAO 43 m telescope, as the FWHP of Fig. 2. continued the telescope beam is 220, much larger than the maximum Trinh X. Thuan et al.: HI observations of blue compact galaxies 21 size of our galaxies ( 30). The same holds for the north- south beam of the Nan¸≤ cay telescope which has a FWHP of 220. But the east-west beam of the Nan¸cay radio tele- scope has a FWHP of only 3.70, and a beam correction needs to be applied. We follow Thuan & Martin (1981) in assuming that the neutral gas is distributed like an ellipti- cal Gaussian with half-power major and minor axis a and b in arcmin. Then: 2 2 2 2 2 1/2 Fc = FH 1+(a sin PA + b cos PA)/θ where a and b are the Holmberg diameters given in Col. (5), PA is the position angle in degrees given in Col. (6), and θ is the HPBW of the Nan¸cay telescope in the East-West direction. The beam correction are generally small, between 1.01 and 1.03. For only a few BCGs does the correction factor reach 1.10 1.18. − Column (13). Logarithm of the hydrogen mass MH in Fig. 3. Histogram of the number of all non-confused observed solar masses calculated from: (dashed line) and detected (solid line) BCGs versus heliocen- 5 1 2 2 tric velocity MH =2.36 10 Fc (Jy km s− )D (Mpc ) × where Fc is the corrected flux density given in Col. (12) and D the distance to the galaxy given in Col. (8). Figures 1 and 2 show in order of increasing right as- Column (14). Telescope used (G = Green Bank, N = cension the HI profiles of the BCGs listed respectively in Nan¸cay) and last two digits of the year of observation (The Tables 1 and 2. Several of the BCGs in Table 1 have previ- observation year ranges from 1992 to 1996). An asterisk ous HI measurements. The detailed references are given in in Table 1 means that there is additional information in the Notes section. Comparison of our measurements with the notes. All entries in Table 2 have supplemental notes. those of previous authors is given in Appendix A. Table 1 contains 79 entries with 34 galaxies in the sta- tistical sample. Table 2 contains 54 entries but only 53 are BCGs as 4. Discussion and summary 1114+5145 UGC6074 is not a BCG and has been ob- served to check≡ for confusion with the BCG 1114+517 We present here the HI observations of 79 galaxies of a MK1445. Out of the 53 BCGs, we have determined that≡ statistical sample of 88 BCGs selected from the First and 32 BCGs are confused (see notes). The 21 non-confused Second Byurakan objective prism surveys to have a HII BCGs in Table 2 are: 0201+284, 0756+611, 0912+599, region-like spectrum, an equivalent width of the [O III] 1028+566, 1054+504, 1057+511A, 1123+576, 1137+589, λ5007 line larger than 50 A,˚ and a heliocentric velocity ≈ 1 1144+591, 1149+596, 1216+551, 1221+545B, 1314+605, less than or equal to 6000 km s− . This statistical BCG 1340+529, 1341+529, 1523+519, 1533+469, 1542+573B, sample shall be used in a subsequent paper to: 1) study the 1632+578, 2304+097 and 2311+235. They are marked by physical parameters governing the burst mode of star for- an asterisk in Col. 1. Table 2 contains 29 galaxies from mation in dwarf galaxies; 2) study the chemical evolution the statistical sample, with 11 non-confused galaxies and of dwarf galaxies and 3) compare statistically the prop- 18 confused galaxies, among which are the pairs of BCGs erties of BCGs with those of other types of dwarf galax- 0926+606 A and B and 1011+600 and 1011+601 which ies. For comparison, we have also observed an additional are listed in a single entry. 20 BCGs in the SBS zone with weaker emission lines, 47 1 Table 3 lists the BCGs which were not detected. It BCGs with V 6000 km s− not in the SBS zone and ≤ 1 is organized as follows: the galaxy’s IAU name (Col. 1), 17 BCGs in the SBS zone with V 6000 km s− ,which cross-reference to other names (Col. 2), its 1950 coordi- are of particular astrophysical interest.≥ For the statistical nates (Cols. 3 and 4). The heliocentric optical velocity on sample which contains 61 non-confused galaxies, we de- which the receiver was centered is given in Col. 5. The tected 34 BCGs with S/N 3 4 (Table 1) and 11 with NRAO and Nan¸cay receivers covered respectively a veloc- 2 S/N 3 and no confusion≥ − (Table 2), giving a detec- 1 ≤ ≤ ity range of 1350 and 4225 km s− . Col. 6 lists the rms tion rate of 74%. This is to be compared with the 80% noise in mJy of the spectrum smoothed to a velocity reso- detection rate≈ of Thuan & Martin (1981). 1 lution of 16 km s− for the Green Bank spectra and of Figure 3 shows the histogram of all non-confused ob- ∼ 1 21 km s− for the Nan¸cay spectra. Finally, Col. 7 gives served (dashed line) and detected (solid line) BCGs as a ∼the telescope used and the year of the observations. An function of heliocentric velocity. It is seen that the de- asterisk signifies that more information can be found in tection rate is roughly constant, equal to 75%, out to 1 ≈ the notes. 6000 km s− , so that the complete statistical sample does 22 Trinh X. Thuan et al.: HI observations of blue compact galaxies

Fig. 4. Histogram of profile widths W for the 45 detected 50 Fig. 5. Histogram of HI masses for the 45 detected BCGs in the BCGs in the statistical sample (dashed line) and for the 100 statistical sample (dashed line) and for the 100 detected BCGs detected BCGs in the enlarged sample (solid line) in the enlarged sample (solid line). The dash-dotted line shows the histogram for the upper limits for the 37 undetected BCGs 1 1 listed in Table 3. A Hubble constant of 75 km s− Mpc− has not suffer from any bias due to telescope sensitivity drop been adopted off.

Figure 4 shows the distribution of W50,thevelocity width at half-maximum for both the statistical sample the statistical sample, confirming again that there is no 1 with V 6000 km s− (a total of 45 galaxies, dashed selection effect in the latter due to telescope sensitivities. line) and≤ all detected BGGs (a total of 100 galaxies, solid From the notes to Tables 1 and 2 we can estimate that line). The peak at 50 km s 1 is due mainly to the sta- at least 35% of the BCGs in the statistical sample show − ∼ tistical sample and∼ may be slightly artificially enhanced evidence for being member of a pair, a group, or for signs as a third of the objects contributing to this peak are of tidal interaction with another galaxy. This percentage is from Table 2 with lower signal-to-noise ratio profiles and similar to that found by Campos-Aguilar & Moles (1991) hence with less reliable widths. Most of the statistical and Campos-Aguilar et al. (1993) for other BCG samples. 1 sample shows widths 160 km s− . The mean width is 1 ≤ 92 48 km s− . These relatively small widths are char- ± Acknowledgements. The Lyon-Meudon Extragalactic Data- acteristic of dwarf galaxies. The histogram of all detected base was very useful for the confusion analysis of our data 1 BCGs shows a larger proportion of widths 60 km s− ) and we acknowledge the efforts of the team of people who 1 ≥ with a high end extending to 300 km s− , implying rota- created and manage it. S.A.P. thanks the ESO C& EE tional velocities comparable to those of large disk galaxies. program for partial financial support through Travel Grant Some of these high widths are contributed by more distant No. B-02-047. T.X.T. has been partially supported by NSF 1 grant AST-9616863, a visiting professorship at the University (V 6000 km s− ) and hence more luminous and massive BCGs.≥ Figure 5 shows the distribution of hydrogen masses of Paris VII and the Centre National de la Recherche Scientifique. This collaboration was made possible by NATO for both the statistical (dashed line) and the enlarged sam- collaborative research grant No. 921285. T.X.T. and S.A.P. ple of all detected BCGs (solid line). The HI masses for the 7 9 are grateful to Dr. Chantal Balkowski for her hospitality at the statistical sample range between 4 10 M and 5 10 M D´epartement d’Astronomie Extragalactique et de Cosmologie 8 with the distribution peaking at 310 M .TheHImass at the Observatoire de Paris. Finally, we thank the directors ∼ 6 distribution for all detected BCGs extends from 10 M of the Nan¸cay and Green Bank Observatories for generous ∼ to 1010 M , with a broad peak at 109 M .Theshifted allotments of observing time which allowed us to carry this peak toward higher HI masses is again∼ partly due to more project to completion. We thank Claude Carignan for useful distant and more massive galaxies than in the statisti- comments on the manuscript. cal sample. BCGs are gas-rich objects, not a surprising conclusion, as gas is needed to fuel their very intense star- forming activity. We have also shown in dashed-dotted Appendix A: Calibration of the Nan¸cay data lines the distribution of upper limits for M(HI) derived using the data in Table 3, and assuming that the HI flux Since at Nan¸cay, all 9, 18 and 21-cm receivers are per- 1 is less than 2 rms 100 km s− . The HI mass upper limit manently installed in the carriage chariot, the noise diode distribution is very× similar to the HI mass distribution of measurements are not made in the laboratory, but are Trinh X. Thuan et al.: HI observations of blue compact galaxies 23

Table 4. Comparison with other authors

IAU name Integrated flux densities 1 (Jy km s− ) Other Authors This Work 12 3 0034+356 1.56 1.96 0.24 0143+346 3.11 1.99 ± 0.20 0834+518 25.52 22.24± 0.48 0930+554 2.85 2.71 ±0.14 0940+662 2.03 2.86 ± 1.24 0946+558 1.25 2.19 ± 0.90 1001+555 4.23 4.54 ± 0.73 1123+644 5.26 7.52 ± 1.24 1332+518 5.28 4.98 ± 0.53 1535+554 1.77 1.41 ± 0.26 2127+021 2.03 2.00 ± 0.12 ± 2214+162 2.24 1.63 0.22 Fig. 6. Integrated HI flux densities from other authors (ordi- ± 2220+377 7.82 8.89 0.38 nate axis) versus our Nan¸cay and Green Bank measurements ± 2233+200 5.28 4.47 0.37 (abscissa axis) for a sample of 15 common galaxies. The solid ± 2246+315 3.38 2.32 0.27 line represents equality ±

represents equality. The data points scatter evenly on ei- made through drift scan observations of standard radio- ther side of the equality line, demonstrating the correct- continuum sources. Full sets of noise diode temperatures ness of our flux calibration. are measured twice a year for many observation frequen- cies and polarizations, on several extragalactic radio-con- tinuum sources. References Calibration measurements were made at three frequen- cies: 1370, 1400 and 1425 MHz. A general drift of the noise Armstrong J.T., Wootten A., 1986, in Light on Dark Matter: diode temperature as a function of time is seen. The jump 1st IRAS Conf., Knudsen, p. 439 occurring on July 24, 1994 (hereafter 940724) is due to a Bottinelli L., Gouguenheim L., Theureau G., Coudreau N., hardware change. Paturel G., 1999, A&AS 135, 429 Our observations were performed between November Campos-Aguilar A., Moles M., 1991, A&A 241, 358 1992 and mid–1996, but most of the data were taken Campos-Aguilar A., Moles M., Masegosa G., 1993, AJ 106, 1784 in 1993 and 1994. The main variations of the noise Carigi L., Colin P., Peimbert M., Sarmiento A., 1995, ApJ 445, diode temperature are due to the changing observation 98 frequencies, corresponding to radial velocities of 500 Fanelli M.N., O’Connell R.W., Thuan T.X., 1988, ApJ 334, 1 − 6000 km s− . The following formulas were used: 665 T<940724 = 223.3 0.14 F and T>940724 =63.1 0.032 F Garcia A.M., 1993, A&AS 100, 47 where T is the estimated− × noise diode temperature− in×K Gordon D., Gottesman S.T., 1981, AJ 86, 161 and F the observation frequency in MHz. The overall Haynes M.P., Giovanelli R., Starosta B.M., Magri C., 1988, AJ calibration procedure accuracy is 10%. 95, 607 ∼ Haynes M.P., Giovanelli R., 1991, ApJS 77, 331 Hickson P., 1982, ApJ 255, 382 Hoffman G.L., Lu N.Y., Salpeter E.E., 1992, AJ 104, 2086 A1. Comparison with data from other authors Izotov Yu.I., Thuan T.X., 1998, ApJ 500, 188 Izotov Yu.I., Lipovetsky V.A., Guseva N.G., Kniazev A.Yu., Among the galaxies which have been detected with a high Neizvestny S.I., Stepanian J.A., 1993, Astron. Astroph. signal-to-noise ratio in the course of this survey and are Trans. 3, 197 not suffering any confusion, 12 have been observed by Izotov Yu.I., Lipovetsky V.A., Chaffee F.H., Foltz C.B., Guseva other authors and their HI parameters can be found in N.G., Kniazev A.Yu., 1997, ApJ 476, 698 Jackson J., Barret A.H., Amstrong J.T., Ho P.T.P., 1987, AJ the literature. We have also observed 2 more Markarian 93, 531 galaxies (MK 303 and MK 307) to increase our comparison Keel W.C., van Soest E.T.M., 1992, A&AS 94, 553 sample. The comparison sample is given in Table 4, with Kniazev A.Yu., 1995 (private communication) both our HI measurements and those of other authors. Kraan-Korteweg R.C., 1986, A&AS 66, 255 We have plotted in Fig. 6 our measurements against Kunth D., Maurogordato S., Vigroux L., 1988, A&A 204, 10 those of others along with our error bars. The solid line Lewis B.M., 1987, A&AS 63, 515 24 Trinh X. Thuan et al.: HI observations of blue compact galaxies

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