Large-Scale Structures Behind the Milky Way from Near-IR Surveys

About 25% of the optical extragalactic sky is obscured by the dust and stars of our Milky Way. Dynamically important structures might still lie hidden in this zone. Various approaches are presently being employed to uncover the galaxy distribution in the Zone of Avoidance (ZOA) but all suffer from (different) limitations and selection effects. We investigated the potential of using the DENIS NIR survey for studies of galaxies behind the obscuration layer of our Milky Way and for mapping the Galactic extinction. As a pilot study, we recovered DENIS I, J and K band images of heavily obscured but optically still visible galaxies. We determined the I, J and K band luminosity functions of galaxies on three DENIS strips that cross the center of the nearby, low-latitude, rich cluster Abell 3627. The extinction-corrected I-J and J-K colours of these cluster galaxies compare well with that of an unobscured cluster. We searched for and identified galaxies at latitudes where the Milky Way remains fully opaque (|b| 4-5mag) - in a systematic search as well as around positions of galaxies detected with the blind HI survey of the ZOA currently conducted with the Multibeam Receiver of the Parkes Radiotelescope.Comment: 12 pages, including 5 PS figures, LaTeX, uses crckapb.sty and epsf.tex. Better resolved figures available upon request. To appear in proceedings of the 3rd Euroconference (Meudon, France, June 1997) on ``The Impact of Near IR Surveys'', Kluwer 199

HI Bright Galaxies in the Southern Zone of Avoidance

A blind survey for HI bright galaxies in the southern Zone of Avoidance, (212 deg < l < 36 deg; |b| < 5 deg), has been made with the 21 cm multibeam receiver on the Parkes 64 m radiotelescope. The survey, sensitive to normal spiral galaxies to a distance of about 40 Mpc and more nearby dwarfs, detected 110 galaxies. Of these, 67 have no counterparts in the NASA/IPAC Extragalactic Database. In general, the uncataloged galaxies lie behind thicker obscuration than do the cataloged objects. All of the newly-discovered galaxies have HI flux integrals more than an order of magnitude lower than the Circinus galaxy. The survey recovers the Puppis cluster and foreground group (Kraan-Korteweg & Huchtmeier 1992), and the Local Void remains empty. The HI mass function derived for the sample is satisfactorily fit by a Schechter function with parameters alpha = 1.51 +- 0.12, Phi* = 0.006 +- 0.003, and log M* = 9.7 +- 0.10.Comment: To appear in The Astronomical Journa

The Parkes HI Zone of Avoidance Survey

A blind HI survey of the extragalactic sky behind the southern Milky Way has been conducted with the multibeam receiver on the 64-m Parkes radio telescope. The survey covers the Galactic longitude range 212 < l < 36 and Galactic latitudes |b| < 5, and yields 883 galaxies to a recessional velocity of 12,000 km/s. The survey covers the sky within the HIPASS area to greater sensitivity, finding lower HI-mass galaxies at all distances, and probing more completely the large-scale structures at and beyond the distance of the Great Attractor. Fifty-one percent of the HI detections have an optical/NIR counterpart in the literature. A further 27% have new counterparts found in existing, or newly obtained, optical/NIR images. The counterpart rate drops in regions of high foreground stellar crowding and extinction, and for low-HI mass objects. Only 8% of all counterparts have a previous optical redshift measurement. A notable new galaxy is HIZOA J1353-58, a possible companion to the Circinus galaxy. Merging this catalog with the similarly-conducted northern extension (Donley et al. 2005), large-scale structures are delineated, including those within the Puppis and Great Attractor regions, and the Local Void. Several newly-identified structures are revealed here for the first time. Three new galaxy concentrations (NW1, NW2 and NW3) are key in confirming the diagonal crossing of the Great Attractor Wall between the Norma cluster and the CIZA J1324.7-5736 cluster. Further contributors to the general mass overdensity in that area are two new clusters (CW1 and CW2) in the nearer Centaurus Wall, one of which forms part of the striking 180 deg (100/h Mpc) long filament that dominates the southern sky at velocities of ~3000 km/s, and the suggestion of a further Wall at the Great Attractor distance at slightly higher longitudes.Comment: Published in Astronomical Journal 9 February 2016 (accepted 26 September 2015); 42 pages, 7 tables, 18 figures, main figures data tables only available in the on-line version of journa

New HI-detected Galaxies in the Zone of Avoidance

We present the first results of a blind HI survey for galaxies in the southern Zone of Avoidance with a multibeam receiver on the Parkes telescope. This survey is eventually expected to catalog several thousand galaxies within Galactic latitude |b|<5 degrees, mostly unrecognised before due to Galactic extinction and confusion. We present here results of the first three detections to have been imaged with the Australia Telescope Compact Array (ATCA). The galaxies all lie near Galactic longitude 325 degrees and were selected because of their large angular sizes, up to 1.3 degrees. Linear sizes range from 53 to 108 kpc. The first galaxy is a massive 5.7x10^11 solar mass disk galaxy with a faint optical counterpart, SGC 1511.1--5249. The second is probably an interacting group of galaxies straddling the Galactic equator. No optical identification is possible. The third object appears to be an interacting pair of low column density galaxies, possibly belonging to an extended Circinus or Centaurus A galaxy group. No optical counterpart has been seen despite the predicted extinction (A(B) = 2.7 - 4.4 mag) not being excessive. We discuss the implications of the results, in particular the low HI column densities (~10^19 atoms/sq.cm) found for two of the three galaxies.Comment: 17 pages, 8 figures (Fig.1 in three parts, Fig.5 in two parts). To appear in Astronomical Journal (Dec 1998). See http://www.atnf.csiro.au/research/multibea

The influence of the polyene filipin on the extrinsic pathway of blood coagulation

The inhibition by filipin in the extrinsic blood clotting system takes place at two sites: (1) at the interaction of factor VII, tissue thromboplastin and Ca++, and (2) at the prothrombinase level. Both formation and enzymatic activity of the prothrombinase are inhibited.The cholesterol content of the lipid that is used to form the prothrombinase complex determines the degree of inhibition by filipin. The inhibition increases the higher the sterol content. The adsorption of factors Xa and V onto lipid surface is enhanced by filipin. This increased adsorption does not lead to an increase in prothrombinase production

Redshift clustering in the Hubble Deep Field

We present initial results from a redshift survey carried out with the Low Resolution Imaging Spectrograph on the 10~m W. M. Keck Telescope in the Hubble Deep Field. In the redshift distribution of the 140 extragalactic objects in this sample we find 6 strong peaks, with velocity dispersions of ${\sim}400${\kms}. The areal density of objects within a particular peak, while it may be non-uniform, does not show evidence for strong central concentration. These peaks have characteristics (velocity dispersions, density enhancements, spacing, and spatial extent) similar to those seen in a comparable redshift survey in a different high galactic latitude field (Cohen et al 1996), confirming that the structures are generic. They are probably the high redshift counterparts of huge galaxy structures (``walls'') observed locally.Comment: 14 pages, including 2 figures, to appear in ApJ Letter

Decomposition of meron configuration of SU(2) gauge field

For the meron configuration of the SU(2) gauge field in the four dimensional Minkowskii spacetime, the decomposition into an isovector field \bn, isoscalar fields $\rho$ and $\sigma$, and a U(1) gauge field $C_{\mu}$ is attained by solving the consistency condition for \bn. The resulting \bn turns out to possess two singular points, behave like a monopole-antimonopole pair and reduce to the conventional hedgehog in a special case. The $C_{\mu}$ field also possesses singular points, while $\rho$ and $\sigma$ are regular everywhere.Comment: 18 pages, 5 figures, Sec.4 rewritten. 5 refs. adde