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Gas & Galaxy Evolution
ASP Conference Series, Vol. **VOLUME**, 2000
J. E. Hibbard, M. P. Rupen and J. H. van Gorkom, eds.
The Brightest Galaxies from HIPASS
B. S. Koribalski
Australia Telescope National Facility, CSIRO, P.O. Box 76, Epping,
NSW 1710, Australia
Abstract.
I present the distribution of the brightest galaxies in the southern sky
as obtained from the H i Parkes All-Sky Survey (HIPASS). This survey is
expected to eventually catalog at least ten thousand galaxies, about 30%
of which either were previously uncataloged or had no velocity measure-
ment. The "HIPASS Bright Galaxy Catalog" will contain the thousand
H i brightest galaxies, a preliminary set of 700 is presented here. Most of
the cataloged H i sources can be identied with individual galaxies, but
some correspond to pairs/groups where one or several galaxies as well as
tidal tails/bridges contribute to the H i emission. We found 60 previously
uncataloged galaxies, 33 of which lie in the Zone-of-Avoidance (jbj < 5 ф ;
see Henning et al. 2000). Several sources outside the Zone-of-Avoidance
have no obvious optical counterparts in the Digitized Sky Survey.
The H i Parkes All-Sky Survey was nished in March 2000, followed by the
completion of the deep Zone-of-Avoidance (ZOA) survey in July 2000; northern
extensions to the existing surveys are underway. These large-area blind H i
surveys are possible due to the multibeam system installed at the 64-m Parkes
telescope (for previous H i surveys see e.g. Kerr & Henning 1987 and Zwaan et
al. 1997). For an overview, survey parameters as well as data calibration and
imaging techniques see Staveley-Smith et al. (1996) and Barnes et al. (2000).
HIPASS and ZOA highlights can be found in Kilborn et al. (2000), Juraszek
et al. (2000), Banks et al. (1999), Staveley-Smith et al. (1998), Putman et al.
(1998), as well as several contributions in these proceedings.
To produce a preliminary version of the "HIPASS Bright Galaxy Catalog"
nearly 400 H i data cubes covering the whole southern sky and the full observed
velocity range (i.e. {1281 to 12741 km/s) were searched for the brightest objects
using Virginia Kilborn's program gnder. From this extensive candidate list
a sample with the following parameters was extracted: H i peak ux > 120
mJybeam 1 , systemic velocity 350 { 8000 km s 1 , velocity width 30 { 3000
km s 1 , and Galactic latitude > 3 degr. To this sample we added all known
galaxies with systemic velocities < 350 km s 1 as well as all ZOA shallow survey
galaxies (Henning et al. 2000) when obeying the H i peak ux selection criterion.
All sources in the sample were inspected and parameterized with the miriad
program mbspect and "non-galaxy" entries (e.g. recombination lines, interfer-
ence, continuum ripple, etc.) were removed or cataloged separately (e.g. HVCs).
This procedure resulted in a sub-sample of about 700 galaxies including some
1

2 Koribalski
Figure 1. Sky distribution of the 700 brightest HIPASS galaxies
(Aito projection centered on RA = 12 h ). | The symbols denote dif-
ferent velocity ranges: v sys < 350 (large dotted circle), 0 { 1000 (solid
square), 1000 { 2000 (open triangle), 2000 { 3000 (solid triangle), 3000 {
4000 (?), 4000 { 5000 (x), and 5000 { 6000 (+) km s 1 .
galaxy pairs/groups as well as a few H i clouds with no optical counterparts. For
all but 60 H i sources optical identications were obtained using NED.
Fig. 1 shows the distribution of the brightest HIPASS galaxies. This is the
rst time that galaxy clustering can be studied uninhibited by foreground stars
and dust from our own Galaxy. The most prominent structures in Fig. 1 are the
Supergalactic Plane and the Local Void, but numerous strings of galaxies, galaxy
groups (e.g. Fornax, Sculptor) as well as bubbles can be seen. A histogram of
the systemic velocities of the brightest HIPASS galaxies is shown in Fig. 2. It
peaks, as expected, in the interval 800 to 2000 km s 1 . No bright galaxies were
found with systemic velocities of less than {350 or more than 5500 km s 1 .
We found 60 previously uncataloged H i sources, most of which lie in or close
to the Zone-of-Avoidance or near individual bright stars; two of the new galaxies
are displayed in Fig. 3. The narrow H i velocity widths are typical for most of
the new galaxies outside the Zone-of-Avoidance, indicating either slow rotation
or face-on galaxies. VLA and AT Compact Array follow-up observations of the
most interesting objects are on-going, e.g. to obtain accurate positions as well
as detailed structure and velocity information.
The most prominent source without an optical counterpart is HIPASS
J1712{64 (v sys = 451 km s 1 ; see Kilborn et al. 2000), but equally exciting
is the huge cloud HIPASS J1718{59 (3 degrees in length), only a few degrees
away from J1712{64, but with a slightly lower systemic velocity of 400 km s 1 .
Together with ZOA J1616{55 (Staveley-Smith et al. 1998) and other, much
weaker clouds at similar velocities, these objects might be related to the Magel-
lanic Clouds and the Leading Arm (Putman et al. 1998). Detailed studies are
under way.

The Brightest Galaxies from HIPASS 3
Figure 2. Histogram of the H i systemic velocities of the bright-
est galaxies obtained from HIPASS. The displayed velocity range was
searched except for the span from {350 to +350 km s 1 where only
known galaxies with an H i peak ux >120 mJybeam 1 were added.
Of the 35 potential Sculptor group members in the velocity range from
zero to 800 km s 1 we detected 25 (20 of which are part of the current bright
galaxy catalog), six were not detected and four objects (SC 02, SC 18, SC 24,
and SC 42) were dismissed because the neutral hydrogen gas at the published
velocities (Cote et al. 1997) appears to be part of an HVC complex.
The nal version of the \HIPASS Bright Galaxy Catalog" will contain 1000
galaxies with H i peak ux  >90 mJybeam 1 and velocity width > 10 km s 1
(Koribalski et al. 2000, in prep.). The H i mass function, catalog completeness,
as well as H i and optical galaxy parameters will be discussed.
Acknowledgments. This paper is the result of a joint eort of members of the
HIPASS and ZOA teams who are gratefully acknowledged. I wish to particularly thank
Virginia Kilborn, Lister Staveley-Smith and Stuart Ryder for their continuous contri-
butions. Use of the NASA/IPAC Extragalactic Database (NED) and the Digitized Sky
Survey (DSS) material (UKST/ROE/AAO/STScI) is acknowledged.
References
Banks, G.D., Disney, M.J., Knezek, P.M., et al. 1999, ApJ 524, 612
Barnes, D.G., Staveley-Smith, L., de Blok, W.J.G, et al. 2000, MNRAS, submitted
Cote, S., Freeman, K., Carignan, C., Quinn, P.J. 1997, AJ 114, 1313
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4 Koribalski
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Figure 3. Two of the new galaxies, HIPASS J1004{73 (top) and
HIPASS J1248{08 (bottom), are displayed: HIPASS spectra on the
left and optical DSS images, centered on the H i position, on the right.
Top: HIPASS J1004{73 (v sys = 1245 km s 1 , w 20 = 90 km s 1 , b =
{14: ф 4). There is only one extended source in the DSS image within
the error radius of the H i position (10 h 04 m 07 s , 73 ф 50 0 50 00 ), a dif-
fuse, possibly face-on optical galaxy at 10 h 04 m 57: s 5, 73 ф 51 0 17: 00 3. |
Bottom: HIPASS J1248{08 (v sys = 1493 km s 1 , w 20 = 80 km s 1 ).
Although there are numerous uncataloged optical galaxies in this DSS
image, the optical counterpart is most likely the closest object to
the H i position (12 h 48 m 28 s , 8 ф 1 0 49 00 ), a bright compact galaxy at
12 h 48 m 31: s 2, 8 ф 2 0 37: 00 8 situated near a bright star.