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We present the Pilot Survey Phase 2 data release for the Wide-field ASKAP L-band Legacy All-sky Blind surveY (WALLABY), carried-out using the Australian SKA Pathfinder (ASKAP). We present 1760 HI detections (with a default spatial resolution of 30") from three pilot fields including the NGC 5044 and NGC 4808 groups as well as the Vela field, covering a total of ~180 deg$^2$ of the sky and spanning a redshift up to $z \simeq 0.09$. This release also includes kinematic models for over 126 spatially resolved galaxies. The observed median rms noise in the image cubes is 1.7 mJy per 30" beam and 18.5 kHz channel. This corresponds to a 5$\sigma$ HI column density sensitivity of $\sim 9.1\times10^{19}(1 + z)^4$ cm$^{-2}$ per 30" beam and $\sim 20$ km/s channel, and a 5$\sigma$ HI mass sensitivity of $\sim 5.5\times10^8 (D/100$ Mpc)$^{2}$ M$_{\odot}$ for point sources. Furthermore, we also present for the first time 12" high-resolution images ("cut-outs") and catalogues for a sub-sample of 80 sources from the Pilot Survey Phase 2 fields. While we are able to recover sources with lower signal-to-noise ratio compared to sources in the Public Data Release 1, we do note that some data quality issues still persist, notably, flux discrepancies that are linked to the impact of side lobes associated with the dirty beams due to inadequate deconvolution. However, in spite of these limitations, the WALLABY Pilot Survey Phase 2 has already produced roughly a third of the number of HIPASS sources, making this the largest spatially resolved HI sample from a single survey to date., Comment: 25 pages, 16 figures, 6 tables, accepted for publication in Publications of the Astronomical Society of Australia (PASA)

To learn more about the properties of the Vela Supercluster (VSCL) located behind the Milky Way at $cz\sim 18000$~km~s$^{-1}$, we determined the $K_s$-band Luminosity Function (LF) of VC04, the richest known galaxy cluster in the VSCL, and two other VSCL clusters (VC02 and VC08). The galaxy sample is based on NIR observations which are complete to an extinction-corrected absolute magnitude of $M_{Ks}^o<-21.5$ mag ($\sim 2.5$ mag below $M_K^*$), within the clustercentric radius of $r_c<1.5~$Mpc ($\sim 70 \%$ of the Abell radius). For VC04 we obtained 90 new spectroscopic redshifts of galaxies observed with the 11-m Southern African Large Telescope. We found the Schechter parameters of the VC04 LF to be $M^*=-24.41\pm 0.44$ mag, $\alpha=-1.10\pm 0.20$ and $\phi^*=8.84\pm 0.20$. Both the redshift data and the LF confirm VC04 to be a rich, not yet fully relaxed cluster. We independently determined the LF of VC04 on membership defined by the Red-Sequence method and demonstrated that this method can be used in the absence of high spectroscopic coverage over a cluster. This allowed us to determine the LFs of VC02 and VC08. We also derived the LFs of the Coma, Norma and Virgo clusters to similar depth and extent as the VSCL clusters. We found that the Schechter parameters of VC04 are within $1\sigma$ uncertainties of these local clusters, as well as VC02 and VC08. We do not find significant differences between the LFs in the different cluster environments probed in this work down to $M_K^*+2.5$ mag., Comment: 19 pages, 12 figures and 9 tables. Accepted for publication in ApJ

We present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251\deg $\le l \le$ 358\deg and 2\deg $\le l \le$ 61\deg at $|b| \le 1.5\deg $). SMGPS is the largest, most sensitive and highest angular resolution 1 GHz survey of the Plane yet carried out, with an angular resolution of 8" and a broadband RMS sensitivity of $\sim$10--20 $\mu$ Jy/beam. Here we describe the first publicly available data release from SMGPS which comprises data cubes of frequency-resolved images over 908--1656 MHz, power law fits to the images, and broadband zeroth moment integrated intensity images. A thorough assessment of the data quality and guidance for future usage of the data products are given. Finally, we discuss the tremendous potential of SMGPS by showcasing highlights of the Galactic and extragalactic science that it permits. These highlights include the discovery of a new population of non-thermal radio filaments; identification of new candidate supernova remnants, pulsar wind nebulae and planetary nebulae; improved radio/mid-IR classification of rare Luminous Blue Variables and discovery of associated extended radio nebulae; new radio stars identified by Bayesian cross-matching techniques; the realisation that many of the largest radio-quiet WISE HII region candidates are not true HII regions; and a large sample of previously undiscovered background HI galaxies in the Zone of Avoidance., Comment: Accepted for publication in MNRAS. The data release is live and links can be found in the Data Availability Statement in the paper

We present six deep Near-InfraRed (JHK_s) photometric catalogues of galaxies identified in six cluster candidates (VC02, VC04, VC05, VC08, VC10, VC11) within the Vela Supercluster (VSCL) as part of our efforts to learn more about this large supercluster which extends across the zone of avoidance (l=272.5 \pm 20 deg, b= \pm 10 deg, at cz~ 18000 km/s). The observations were conducted with the InfraRed Survey Facility (IRSF), a 1.4m telescope situated at the South African Astronomical Observatory (SAAO) in Sutherland. The images in each cluster cover ~ 80% of their respective Abell radii. We identified a total number of 1715 galaxies distributed over the six cluster candidates, of which only ~ 15% were previously known. We study the structures and richnesses of the six clusters out to the cluster-centric completeness radius of r_c<1.5 Mpc and magnitude completeness limit of K_s^0<15.5 mag, using their iso-density contour maps and radial density profiles. The analysis shows VC04 to be the richest of the six. It is a massive cluster comparable to the Coma and Norma clusters, although its velocity dispersion, sigma=455 km/s, seems rather low for a rich cluster. VC02 and VC05 are found to be relatively rich clusters while VC08 is rather poor. Also, VC05 has the highest central number density among the six. VC11 is an intermediate cluster that contains two major subclusters while VC10 has a filament-like structure and is likely not to be a cluster after all., Comment: 18 pages, 10 Figures, 13 Tables. Accepted for publication in MNRAS

MeerKAT's large number of antennas, spanning 8 km with a densely packed 1 km core, create a powerful instrument for wide-area surveys, with high sensitivity over a wide range of angular scales. The MeerKAT Galaxy Cluster Legacy Survey (MGCLS) is a programme of long-track MeerKAT L-band (900-1670 MHz) observations of 115 galaxy clusters, observed for $\sim$6-10 hours each in full polarisation. The first legacy product data release (DR1), made available with this paper, includes the MeerKAT visibilities, basic image cubes at $\sim$8" resolution, and enhanced spectral and polarisation image cubes at $\sim$8" and 15" resolutions. Typical sensitivities for the full-resolution MGCLS image products are $\sim$3-5 {\mu}Jy/beam. The basic cubes are full-field and span 4 deg^2. The enhanced products consist of the inner 1.44 deg^2 field of view, corrected for the primary beam. The survey is fully sensitive to structures up to $\sim$10' scales and the wide bandwidth allows spectral and Faraday rotation mapping. HI mapping at 209 kHz resolution can be done at $0

We use near-infrared (J-K)-colours of bright 2MASS galaxies, measured within a 7"-radius aperture, to calibrate the Schlegel et al. (1998) DIRBE/IRAS Galactic extinction map at low Galactic latitudes ($|b| < 10^{\rm o}$). Using 3460 galaxies covering a large range in extinction (up to $A_K$ = 1.15 or E(B-V) ~ 3.19), we derive a correction factor $f = 0.83 \pm 0.01$ by fitting a linear regression to the colour-extinction relation, confirming that the Schlegel et al. maps overestimate the extinction. We argue that the use of only a small range in extinction (e.g., $A_K$ < 0.4) increases the uncertainty in the correction factor and may overestimate it. Our data confirms the Fitzpatrick (1999) extinction law for the J- and K-band. We also tested four all-sky extinction maps based on Planck satellite data. All maps require a correction factor as well. In three cases the application of the respective extinction correction to the galaxy colours results in a reduced scatter in the colour-extinction relation, indicating a more reliable extinction correction. Finally, the large galaxy sample allows an analysis of the calibration of the extinction maps as a function of Galactic longitude and latitude. For all but one extinction map we find a marked offset between the Galactic Centre and Anticentre region, but not with the dipole of the Cosmic Microwave Background. Based on our analysis, we recommend the use of the GNILC extinction map by Planck Collaboration (2016b) with a correction factor $f = 0.86 \pm 0.01$., Comment: 20 pages, 14 figures, accepted by MNRAS; online material available through MNRAS, CDS or by request from the main author

We present the HI emission project within the MIGHTEE survey, currently being carried out with the newly commissioned MeerKAT radio telescope. This is one of the first deep, blind, medium-wide interferometric surveys for neutral hydrogen (HI) ever undertaken, extending our knowledge of HI emission to z=0.6. The science goals of this medium-deep, medium-wide survey are extensive, including the evolution of the neutral gas content of galaxies over the past 5 billion years. Simulations predict nearly 3000 galaxies over 0

We present a catalogue of 261 new infrared selected members of the 3C129 galaxy cluster. The cluster, located at $z \approx$ 0.02, forms part of the Perseus-Pisces filament and is obscured at optical wavelengths due to its location in the zone of avoidance. We identified these galaxies using the $J-$ and $K-$band imaging data provided by the UKIDSS Galactic Plane Survey within an area with a radius of $1.1^{\circ}$ centred on the X-ray emission of the cluster at $\ell, b \approx 160.52^{\circ}, 0.27^{\circ}$. A total of 26 of the identified galaxy members have known redshifts 24 of which are from our 2016 Westerbork HI survey and two are from optical spectroscopy. An analysis of the galaxy density at the core of the 3C129 cluster shows it to be less dense than the Coma and Norma clusters, but comparable to the galaxy density in the core of the Perseus cluster. From an assessment of the spatial and velocity distributions of the 3C129 cluster galaxies that have redshifts, we derived a velocity of $cz = 5227 \pm 171$ km/s and $\sigma = 1097 \pm 252$ km/s for the main cluster, with a substructure in the cluster outskirts at $cz = 6923 \pm 71$ km/s with $\sigma = 422 \pm 100$ km/s. The presence of this substructure is consistent with previous claims based on the X-ray analysis that the cluster is not yet virialised and may have undergone a recent merger., Comment: 33 pages, 16 figures, includes an appendix, accepted for publication in A&A

We present the galaxy group catalogue for the recently-completed 2MASS Redshift Survey (2MRS, Macri2019) which consists of 44572 redshifts, including 1041 new measurements for galaxies mostly located within the Zone of Avoidance. The galaxy group catalogue is generated by using a novel, graph-theory based, modified version of the Friends-of-Friends algorithm. Several graph-theory examples are presented throughout this paper, including a new method for identifying substructures within groups. The results and graph-theory methods have been thoroughly interrogated against previous 2MRS group catalogues and a Theoretical Astrophysical Observatory (TAO) mock by making use of cutting-edge visualization techniques including immersive facilities, a digital planetarium, and virtual reality. This has resulted in a stable and robust catalogue with on-sky positions and line-of-sight distances within 0.5 Mpc and 2 Mpc, respectively, and has recovered all major groups and clusters. The final catalogue consists of 3022 groups, resulting in the most complete "whole-sky" galaxy group catalogue to date. We determine the 3D positions of these groups, as well as their luminosity and comoving distances, observed and corrected number of members, richness metric, velocity dispersion, and estimates of $R_{200}$ and $M_{200}$. We present three additional data products, i.e. the 2MRS galaxies found in groups, a catalogue of subgroups, and a catalogue of 687 new group candidates with no counterparts in previous 2MRS-based analyses., Comment: 22 pages, 15 figures; accepted for publication in MNRAS; high quality PDF and python code available at https://github.com/BrutishGuy/pyfriends

An analysis is presented of the optical polarimetric and multicolour photometric ($BVRJ$) behaviour of the blazar PKS 2155$-$304 during an outburst in 2010. This flare develops over roughly 117 days, with a flux doubling time $\tau \sim 11$ days that increases from blue to red wavelengths. The polarization angle is initially aligned with the jet axis but rotates by roughly $90^\circ$ as the flare grows. Two distinct states are evident at low and high fluxes. Below 18 mJy, the polarization angle takes on a wide range of values, without any clear relation to the flux. In contrast, there is a positive correlation between the polarization angle and flux above 18 mJy. The polarization degree does not display a clear correlation with the flux. We find that the photopolarimetric behaviour for the high flux state can be attributed to a variable component with a steady power-law spectral energy distribution and high optical polarization degree (13.3%). These properties are interpreted within the shock-in-jet model, which shows that the observed variability can be explained by a shock that is seen nearly edge-on. Some parameters derived for the relativistic jet within the shock-in-jet model are: $B=0.06$ G for the magnetic field, $\delta=22.3$ for the Doppler factor and $\Phi=2.6^\circ$ for the viewing angle., Comment: 8 pages, 9 figures

The Widefield ASKAP L-band Legacy All-sky Blind surveY (WALLABY) is a next-generation survey of neutral hydrogen (HI) in the Local Universe. It uses the widefield, high-resolution capability of the Australian Square Kilometer Array Pathfinder (ASKAP), a radio interferometer consisting of 36 x 12-m dishes equipped with Phased-Array Feeds (PAFs), located in an extremely radio-quiet zone in Western Australia. WALLABY aims to survey three-quarters of the sky (-90 degr < Dec < +30 degr) to a redshift of z < 0.26, and generate spectral line image cubes at ~30 arcsec resolution and ~1.6 mJy/beam per 4 km/s channel sensitivity. ASKAP's instantaneous field of view at 1.4 GHz, delivered by the PAF's 36 beams, is about 30 sq deg. At an integrated signal-to-noise ratio of five, WALLABY is expected to detect over half a million galaxies with a mean redshift of z ~ 0.05 (~200 Mpc). The scientific goals of WALLABY include: (a) a census of gas-rich galaxies in the vicinity of the Local Group; (b) a study of the HI properties of galaxies, groups and clusters, in particular the influence of the environment on galaxy evolution; and (c) the refinement of cosmological parameters using the spatial and redshift distribution of low-bias gas-rich galaxies. For context we provide an overview of previous large-scale HI surveys. Combined with existing and new multi-wavelength sky surveys, WALLABY will enable an exciting new generation of panchromatic studies of the Local Universe. - First results from the WALLABY pilot survey are revealed, with initial data products publicly available in the CSIRO ASKAP Science Data Archive (CASDA)., Comment: Accepted for publication in ApSS (38 pages, 14 figures), see also https://www.atnf.csiro.au/research/WALLABY/ - Contact email: Baerbel.Koribalski@csiro.au

MHONGOOSE is a deep survey of the neutral hydrogen distribution in a representative sample of 30 nearby disk and dwarf galaxies with HI masses from 10^6 to ~10^{11} M_sun, and luminosities from M_R ~ -12 to M_R ~ -22. The sample is selected to uniformly cover the available range in log(M_HI). Our extremely deep observations, down to HI column density limits of well below 10^{18} cm^{-2} - or a few hundred times fainter than the typical HI disks in galaxies - will directly detect the effects of cold accretion from the intergalactic medium and the links with the cosmic web. These observations will be the first ever to probe the very low-column density neutral gas in galaxies at these high resolutions. Combination with data at other wavelengths, most of it already available, will enable accurate modelling of the properties and evolution of the mass components in these galaxies and link these with the effects of environment, dark matter distribution, and other fundamental properties such as halo mass and angular momentum. MHONGOOSE can already start addressing some of the SKA-1 science goals and will provide a comprehensive inventory of the processes driving the transformation and evolution of galaxies in the nearby universe at high resolution and over 5 orders of magnitude in column density. It will be a Nearby Galaxies Legacy Survey that will be unsurpassed until the advent of the SKA, and can serve as a highly visible, lasting statement of MeerKAT's capabilities., Comment: To be published in "MeerKAT Science: On the Pathway to the SKA". Proceedings of Science. Workshop held 25-27 May, 2016 Stellenbosch, South Africa

We present the science case and observations plan of the MeerKAT Fornax Survey, an HI and radio continuum survey of the Fornax galaxy cluster to be carried out with the SKA precursor MeerKAT. Fornax is the second most massive cluster within 20 Mpc and the largest nearby cluster in the southern hemisphere. Its low X-ray luminosity makes it representative of the environment where most galaxies live and where substantial galaxy evolution takes place. Fornax's ongoing growth makes it an excellent laboratory for studying the assembly of clusters, the physics of gas accretion and stripping in galaxies falling in the cluster, and the connection between these processes and the neutral medium in the cosmic web. We will observe a region of 12 deg$^2$ reaching a projected distance of 1.5 Mpc from the cluster centre. This will cover a wide range of environment density out to the outskirts of the cluster, where gas-rich in-falling groups are found. We will: study the HI morphology of resolved galaxies down to a column density of a few times 1e+19 cm$^{-2}$ at a resolution of 1 kpc; measure the slope of the HI mass function down to M(HI) 5e+5 M(sun); and attempt to detect HI in the cosmic web reaching a column density of 1e+18 cm$^{-2}$ at a resolution of 10 kpc., Comment: Proceedings of Science, "MeerKAT Science: On the Pathway to the SKA", Stellenbosch, 25-27 May 2016

Recent spectroscopic observations of a few thousand partially obscured galaxies in the Vela constellation revealed a massive overdensity on supercluster scales straddling the Galactic Equator (l $\sim$ 272.5deg) at $cz \sim 18000$km/s. It remained unrecognised because it is located just beyond the boundaries and volumes of systematic whole-sky redshift and peculiar velocity surveys - and is obscured by the Milky Way. The structure lies close to the apex where residual bulkflows suggest considerable mass excess. The uncovered Vela Supercluster (VSCL) conforms of a confluence of merging walls, but its core remains uncharted. At the thickest foreground dust column densities (|b| < 6 deg) galaxies are not visible and optical spectroscopy is not effective. This precludes a reliable estimate of the mass of VSCL, hence its effect on the cosmic flow field and the peculiar velocity of the Local Group. Only systematic HI-surveys can bridge that gap. We have run simulations and will present early-science observing scenarios with MeerKAT 32 (M32) to complete the census of this dynamically and cosmologically relevant supercluster. M32 has been put forward because this pilot project will also serve as precursor project for HI MeerKAT Large Survey Projects, like Fornax and Laduma. Our calculations have shown that a survey area of the fully obscured part of the supercluster, where the two walls cross and the potential core of the supercluster resides, can be achieved on reasonable time-scales (200 hrs) with M32., Comment: 10 pages, 3 figures, accepted for publication, Proceedings of Science, workshop on "MeerKAT Science: On the Pathway to the SKA", held in Stellenbosch 25-27 May 2016

Evidence for the presence of quasi-periodic oscillations (QPOs) in the optical polarization of the blazar PKS 2155-304, during a period of enhanced gamma-ray brightness, is presented. The periodogram of the polarized flux revealed the existence of a prominent peak at $T\sim 13$ min, detected at >99.7% significance, and $T\sim 30$ min, which was nominally significant at >99%. This is the first evidence of QPOs in the polarization of an active galactic nucleus, potentially opening up a new avenue of studying this phenomenon., Comment: 5 pages, 5 figures, accepted for publication in MNRAS

To investigate galaxy properties as a function of their total stellar mass, we obtained 21cm HI line observations at the 100-m class Nan\c{c}ay Radio Telescope of 2839 galaxies from the Sloan Digital Sky Survey (SDSS) in the Local Volume (900

We present results of a blind 21cm HI-line imaging survey of a galaxy overdensity located behind the Milky Way at $\ell,b$ $\approx$ 160 deg, 0.5 deg. The overdensity corresponds to a Zone-of-Avoidance crossing of the Perseus-Pisces Supercluster filament. Although it is known that this filament contains an X-ray galaxy cluster (3C129) hosting two strong radio galaxies, little is known about galaxies associated with this potentially rich cluster because of the high Galactic dust extinction. We mapped a sky area of $\sim$9.6 sq.deg using the Westerbork Synthesis Radio Telescope in a hexagonal mosaic of 35 pointings observed for 12 hours each, in the radial velocity range $cz = 2400 - 16600$ km/s. The survey has a sensitivity of 0.36 mJy/beam rms at a velocity resolution of 16.5 km/s. We detected 211 galaxies, 62% of which have a near-infrared counterpart in the UKIDSS Galactic Plane Survey. We present a catalogue of the HI properties and an HI atlas containing total intensity maps, position-velocity diagrams, global HI profiles and UKIDSS counterpart images. For the resolved galaxies we also present HI velocity fields and radial HI surface density profiles. A brief analysis of the structures outlined by these galaxies finds that 87 of them lie at the distance of the Perseus-Pisces Supercluster ($cz \sim 4000 - 8000$ km/s) and seem to form part of the 3C129 cluster. Further 72 detections trace an overdensity at a velocity of $cz \approx$ 10000 km/s and seem to coincide with a structure predicted from mass density reconstructions in the first 2MASS Redshift Survey., Comment: 28 pages, 18 figures, 6 Tables, accepted for publication in MNRAS

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 journal

We used the Nan\c{c}ay Radio Telescope (NRT) to measure the 21 cm line emission of near-infrared bright galaxies in the northern Zone of Avoidance (ZoA) without previous redshift determinations. We selected galaxies with extinction-corrected magnitudes $K_s^o \leq 11\hbox{$.\!\!^{\rm m}$}25$ from the 2MASS Extended Source Catalog. These data will complement the existing 2MASS Redshift Survey (2MRS; first data release) as well as the ongoing 2MASS Tully-Fisher survey, both of which exclude the inner ZoA ($|b|< 5^{\circ}$), where the identification of galaxy candidates is the hardest. Of the $\sim$1000 identified 2MASX galaxy candidates we have so far detected 252 to our 3.0 mJy rms sensitivity limit and the velocity limit of 10500 km/s. The resulting redshift distribution reveals various new structures that were hitherto uncharted. They seem to form part of the larger Perseus-Pisces Supercluster (PPS). The most conspicuous is a ridge at about $\ell\approx 160^{\circ}$,$v \approx 6500$ km/s. Within this wall-like structure, two strong radio galaxies (3C 129 and 3C 129.1) are embedded which lie at the same distance as the ridge. They seem to form part of an X-ray cluster. Another prominent filament has been identified crossing the ZoA at $\ell \approx 90^\circ$, hence suggesting the second Perseus-Pisces arm is more extended than previously thought., Comment: 6 pages, 1 figure, in Proceedings of SAIP2012: the 57th Annual Conference of the South African Institute of Physics, edited by Johan Janse van Rensburg (2014), pp. 368 - 372. ISBN: 978-1-77592-070-0

Dust extinction and stellar confusion by the Milky Way reduce the efficiency of detecting galaxies at low Galactic latitudes, creating the so-called Zone of Avoidance. This stands as a stumbling block in charting the distribution of galaxies and cosmic flow fields, and therewith our understanding of the local dynamics in the Universe (CMB dipole, convergence radius of bulk flows). For instance, ZoA galaxies are generally excluded from the whole-sky Tully-Fisher Surveys ($|b| \leq 5^\circ$) even if catalogued. We show here that by fine-tuning the near-infrared TF relation, there is no reason not to extend peculiar velocity surveys deeper into the ZoA. Accurate axial ratios ($b/a$) are crucial to both the TF sample selection and the resulting TF distances. We simulate the effect of dust extinction on the geometrical properties of galaxies. As expected, galaxies appear rounder with increasing obscuration level, even affecting existing TF samples. We derive correction models and demonstrate that we can reliably reproduce the intrinsic axial ratio from the observed value up to extinction level of about $A_J\simeq3$ mag ($A_V\sim11$ mag), we also recover a fair fraction of galaxies that otherwise would fall out of an uncorrected inclination limited galaxy sample. We present a re-calibration of the 2MTF relation in the NIR $J$, $H$, and $K_s$-bands for isophotal rather than total magnitudes, using their same calibration sample. Both TF relations exhibit similar scatter at high Galactic latitudes. However, the isophotal TF relation results in a significant improvement in the scatter for galaxies in the ZoA, and low surface brightness galaxies in general, because isophotal apertures are more robust in the face of significant stellar confusion., Comment: 12 pages, 10 figures, 4 tables, accepted for publication in MNRAS

Supernovae Type Ia display a complex relation with their host galaxies. An important prior to the fit of the supernovae's lightcurve is the distribution of host galaxy extinction values that can be encountered. The SDSS-SN project has published light curve fits using both MLCS2k2 and SALT2. We use the former fits extinction parameter ($A_V$) to map this distribution of extinction values. We explore the dependence of this distribution on four observables; the inclination of the host galaxy disk, radial position of the supernova, redshift of the supernova and host, and the level of star-formation in the host galaxy. The distribution of $A_V$ values encountered by supernovae is typically characterised by: $\rm N_0 ~ e^{-A_V/\tau}$, with $\tau$= 0.4 or 0.33. We find that the inclination correction using an infinitely thin disk for the SNIa is sufficient, resulting in similar exponential $A_V$ distributions for high- and low-inclination disks. The $A_V$ distribution also depends on the radial position in the disk, consistent with previous results on the transparency of spiral disks. The distribution of $A_V$ values narrows with increased star-formation, possibly due to the destruction or dispersion of the dusty ISM by stellar winds prior to the ignition of the supernova. In future supernova searches, certainly the inclination of the host galaxy disk, should be considered in the construction of the \av \ prior with $\tau=0.4/cos(i)$ as the most likely prior in each individual host galaxy's case., Comment: 10 pages, 14 figures, accepted for publication by MNRAS

Dust extinction and stellar confusion of the Milky Way hinder the detection of galaxies at low Galactic latitude, creating the so-called Zone of Avoidance (ZoA). This has hampered our understanding of the local dynamics, cosmic flow fields and the origin of the Cosmic Microwave Background dipole. The ZoA ($|b| \le 5^\circ$) is also excluded from the "whole-sky" Two Micron All-Sky Survey (2MASS) Redshift Survey (2MRS) and 2MASS Tully-Fisher Survey (2MTF). The latter aims to provide distances and peculiar velocities for all bright inclined 2MASS galaxies with $K_s^o$ $\leq 11\hbox{$.\!\!^{\rm m}$}25$. Correspondingly, knowledge about the density distribution in the ZoA remains limited to statistical interpolations. To improve on this bias we pursued two different surveys to fill in the southern and northern ZoA. These data will allow a direct measurement of galaxy peculiar velocities. In this paper we will present a newly derived optimized Tully-Fisher (TF) relation that allow accurate measures of galaxy distances and peculiar velocities for dust-obscured galaxies. We discuss further corrections for magnitudes and biases and present some preliminary results on flow fields in the southern ZoA., Comment: 6 pages, 3 figures, to appear in Proceedings of SAIP2013, the 58th Annual Conference of the South African Institute of Physics, edited by Roelf Botha and Thulani Jili (SAIP and University of Zululand, 2014). ISBN: 978-0-620-62819-8

Australia Telescope Compact Array HI-line observations of the nearby dwarf galaxy NGC 1705 are presented. The data are used to trace the gravitational potential of the galaxy out to several stellar disc scale lengths. A rotation curve is derived for the system and used to generate mass models. Dark matter dominates the gravitational potential at nearly all galactocentric radii. NFW and pseudo-isothermal sphere halo parameterisations allowing for good reproductions of the observations. The models suggest NGC 1705 to have a dark matter halo that it much denser and more compact than previously thought., Comment: Published in MNRAS. 13 pages, 14 figures

Crucial to a quantitative understanding of galaxy evolution are the properties of the inter-stellar medium that regulate galactic-scale star formation activity. We present here the results of a suite of star formation models applied to the nearby blue compact dwarf galaxies NGC 2915 and NGC 1705. Each of these galaxies has a stellar disk embedded in a much larger, essentially star-less HI disk. These atypical stellar morphologies allow for rigorous tests of star formation models that examine the effects on star formation of the HI, stellar and dark matter mass components, as well as the kinematics of the gaseous and stellar disks. We use far ultra-violet and 24 micron imaging from the Galaxy Evolution Explorer and the Spitzer Infrared Nearby Galaxies Survey respectively to map the spatial distribution of the total star formation rate surface density within each galaxy. New high-resolution HI line observations obtained with the Australia Telescope Compact Array are used to study the distribution and dynamics of each galaxy's neutral inter-stellar medium. The standard Toomre Q parameter is unable to distinguish between active and non-active star forming regions, predicting the HI disks of the dwarfs to be sub-critical. Two-fluid instability models incorporating the stellar and dark matter components of each galaxy, in addition to the gaseous component, yield portions of the inner disk unstable. Finally, a formalisation in which the HI kinematics are characterised by the rotational shear of the gas produces models that very accurately match the observations. This suggests the time available for perturbations to collapse in the presence of rotational shear to be an important factor governing galactic-scale star formation., Comment: 27 pages, 20 figures, accepted for publication in AJ

This paper presents the analysis of a deep near-infrared J,H,Ks-imaging survey (37.5 sq deg) aimed at tracing the galaxy distribution of the Great Attractor (GA) in the Zone of Avoidance along the so-called Norma Wall. The resulting galaxy catalog is complete to extinction-corrected magnitudes Ks^o = 14.8 mag for extinctions less than A_K = 1.0 mag and star densities below log N(Ks<14.0) < 4.72. Of the 4360 cataloged galaxies, 99.2% lie in the hereby constrained 89.5% of the survey area. Although the analyzed galaxy distribution reveals no new major galaxy clusters at the GA distance (albeit some more distant ones), the overall number counts and luminosity density indicate a clear and surprisingly smooth overdensity at the GA distance that extends over the whole surveyed region. A mass estimate of the Norma Wall overdensity derived from (a) galaxy number counts and (b) photometric redshift distribution gives a lower value compared to the original prediction by Lynden-Bell et al. 1988 (~14%), but is consistent with more recent independent assessments., Comment: To appear in "Ten years of Infrared Survey Facility and the Future", eds. T. Nagayama, S. Sato, and K. Wakamatsu

The nearby blue compact dwarf, NGC 2915, has its stellar disc embedded in a large, extended (~ 22 B-band scale-lengths) HI disc. New high-resolution HI synthesis observations of NGC 2915 have been obtained with the Australia Telescope Compact Array. These observations provide evidence of extremely complex HI kinematics within the immediate vicinity of the galaxy's star-forming core. We identify and quantify double-peaked HI line profiles near the centre of the galaxy and show that the HI energetics can be accounted for by the mechanical energy output of the central high-mass stellar population within time-scales of 10^6-10^7 yr. Full three-dimensional models of the HI data cube are generated and compared to the observations to test various physical scenarios associated with the high-mass star-forming core of NGC 2915. Purely circular HI kinematics are ruled out together with the possibility of a high-velocity-dispersion inter-stellar medium at inner radii. Radial velocities of ~ 30 km/s are required to describe the central-most HI kinematics of the system. Our results lend themselves to the simple physical scenario in which the young stellar core of the galaxy expels the gas outwards from the centre of the disc, thereby creating a central HI under-density. These kinematics should be thought of as being linked to a central HI outflow rather than a large-scale galactic blow-out or wind., Comment: 11 pages, 6 figures, accepted for publication in MNRAS

HIZOA J0836-43 is the most HI-massive (M_HI = 7.5x10^10 Msun) galaxy detected in the HIPASS volume and lies optically hidden behind the Milky Way. Markedly different from other extreme HI disks in the local universe, it is a luminous infrared galaxy (LIRG) with an actively star forming disk (>50 kpc), central to its ~ 130 kpc gas disk, with a total star formation rate (SFR) of ~20.5 Msun yr^{-1}. Spitzer spectroscopy reveals an unusual combination of powerful polycyclic aromatic hydrocarbon (PAH) emission coupled to a relatively weak warm dust continuum, suggesting photodissociation region (PDR)-dominated emission. Compared to a typical LIRG with similar total infrared luminosity (L_TIR=10^11 Lsun), the PAHs in HIZOA J0836-43 are more than twice as strong, whereas the warm dust continuum (lambda > 20micron) is best fit by a star forming galaxy with L_TIR=10^10 Lsun. Mopra CO observations suggest an extended molecular gas component (H_2 + He > 3.7x10^9 Msun) and a lower limit of ~ 64% for the gas mass fraction; this is above average compared to local disk systems, but similar to that of z~1.5 BzK galaxies (~57%). However, the star formation efficiency (SFE = L_IR/L'_CO) for HIZOA J0836-43 of 140 Lsun (K km s^{-1} pc^2)^{-1} is similar to that of local spirals and other disk galaxies at high redshift, in strong contrast to the increased SFE seen in merging and strongly interacting systems. HIZOA J0836-43 is actively forming stars and building a massive stellar disk. Its evolutionary phase of star formation (M_stellar, SFR, gas fraction) compared to more distant systems suggests that it would be considered typical at redshift z~1. This galaxy provides a rare opportunity in the nearby universe for studying (at z~0.036) how disks were building and galaxies evolving at z~1, when similarly large gas fractions were likely more common., Comment: Accepted for publication in The Astrophysical Journal. 16 pages, 8 figures

NGC 2915 is a nearby blue compact dwarf with a differentially rotating HI disc extending out to ~ 5 R-band R_{25} radii. This disc serves as an ideal tracer of the system's gravitational potential in regions of the galaxy that are dominated by dark matter. We use new HI synthesis observations of NGC 2915, obtained with the Australia Telescope Compact Array, to search for non-circular flows within the outer HI disc. Two independent methods are used, and the results of each interpreted in the context of relevant axisymmetric and non-axisymmetric perturbations of the potential. We find evidence for: (1) elliptical streaming associated with the spiral structure of the HI disc and the central bar-like feature in the mass distribution, (2) a spherical dark matter halo, and (3) an axisymmetric radial outflow of ~ 5-17 km/s (~ 6-20 percent of the circular speed). A possible bar-like perturbation of the potential hinders attempts to unambiguously detect kinematic signatures of radial flows in the HI velocity field. The radial outflows are inconsistent with the plausible disc formation scenario in which gas from the surrounding inter-galactic medium is deposited on the outer HI disc and then transported towards the centre of the galaxy. They are, however, consistent with the possibility of some material being re-distributed towards the outer disc in order to conserve angular momentum as material flows inwards along a bar., Comment: Accepted for publication in MNRAS. 12 pages, 7 figures

We have obtained deep near-infrared $J$- (1.25 $\mu$m), $H$- (1.65$ \mu$m) and $K_s$-band (2.15 $\mu$m) imaging for a sample of six dwarf galaxies ($M_B\ga-17$ mag) in the Local Volume (LV, $D\la10$ Mpc). The sample consists mainly of early-type dwarf galaxies found in various environments in the LV. Two galaxies (LEDA 166099 and UGCA 200) in the sample are detected in the near-infrared for the first time. The deep near-infrared images allow for a detailed study of the photometric and structural properties of each galaxy. The surface brightness profiles of the galaxies are detected down to the ~$24 mag arcsec^{-2}$ isophote in the $J$- and $H$-bands, and $23 mag arcsec^{-2}$ in the $K_s$-band. The total magnitudes of the galaxies are derived in the three wavelength bands. For the brightest galaxies ($M_B\la-15.5$ mag) in the sample, we find that the Two Micron All Sky Survey (2MASS) underestimates the total magnitudes of these systems by up to $\la0.5$ mag. The radial surface brightness profiles of the galaxies are fitted with an exponential (for those galaxies having a stellar disk) or S\'ersic law to derive the structure of the underlying stellar component. In particular, the effective surface brightness ($\mu_e$) and effective radius ($r_e$) are determined from the analytic fits to the surface brightness profile. The $J$-$K_s$ colours for the galaxies have been measured to explore the luminosity-metallicity relation for early-type dwarfs. In addition, the $B$-$K_s$ colours of the galaxies are used to assess their evolutionary state relative to other galaxy morphologies. The total stellar masses of the dwarf galaxies are derived from the $H$-band photometric measurements. These will later be compared to the dynamical mass estimates for the galaxies to determine their dark matter content., Comment: 14 pages, 8 figures, submitted to MNRAS

NGC 2915 is a nearby blue compact dwarf with the HI properties of a late-type spiral. Its large, rotating HI disk (extending out to R ~ 22 B-band scale lengths) and apparent lack of stars in the outer HI disk make it a useful candidate for dark matter studies. New HI synthesis observations of NGC 2915 have been obtained using the Australian Telescope Compact Array. These data are combined with high-quality 3.6 $\mu$m imaging from the Spitzer Infrared Nearby Galaxies Survey. The central regions of the HI disk are shown to consist of two distinct HI concentrations with significantly non-Gaussian line profiles. We fit a tilted ring model to the HI velocity field to derive a rotation curve. This is used as input for mass models that determine the contributions from the stellar and gas disks as well as the dark matter halo. The galaxy is dark-matter-dominated at nearly all radii. At the last measured point of the rotation curve, the total mass to blue light ratio is ~ 140 times solar, making NGC 2915 one of the darkest galaxies known. We show that the stellar disk cannot account for the steeply-rising portion of the observed rotation curve. The best-fitting dark matter halo is a pseudo-isothermal sphere with a core density $\rho_0\sim 0.17 \pm 0.03$ \msun pc$^{-3}$ and a core radius $r_c\sim 0.9 \pm 0.1$ kpc., Comment: MNRAS in press. 17 pages, 15 figures

A pilot survey has been made to obtain 21cm HI emission line profiles for 197 objects in the Zone of Avoidance (ZoA) that were classified as galaxies in the 2MASS all-sky near-infrared Extended Source Catalog (2MASX). 116 of the sources were observed using the Nancay radio telescope, in the 325 to 11,825 km/s range, and the other 81 sources were observed at Arecibo in the -500 to 11,000 km/s range, and for 9 also in the 9,500 to 21,000 km/s range. Global HI line parameters are presented for the 22 and 29 2MASX objects that were detected at Nancay and Arecibo, respectively, as well as upper limits for the undetected 2MASX objects. Whereas object 2MASX J08170147-3410277 appears to be a very massive galaxy with an HI mass of 4.6 x 10E10 Msun, it is clear that only radio synthesis HI imaging observations will allow a firm conclusion on this. Overall, the global properties of the detected galaxies match those of other ZoA HI surveys. Although the detections are as yet too sparse to give further insight into suspected or unknown large-scale structures in the ZoA, they already indicate that an extension of the present pilot survey is bound to quantify filaments, clusters, and voids behind this part of the Milky Way. It is shown that the number of candidate 2MASS-selected ZoA galaxies to be observed in HI could have been reduced by about 15% through examination of composite near-infrared images and the application of extinction-corrected near-infrared colour limits. Present results confirm that the Galactic extinction values from Schlegel et al. (1998) are valid for latitudes above |b|=5 degrees, but increasingly less so for lower latitudes., Comment: 22 pages, 10 figures

A deep K_s-band photometric catalogue of galaxies at the core of the rich, nearby Norma cluster (ACO3627) is presented. The survey covers about 45 by 45 square arcmin (slightly less than 1/3 Abell radius), which corresponds to approx. 0.8 Mpc^2 at the adopted distance (v_cmb/H0) of 70 Mpc of this cluster. The survey is estimated to be complete to a magnitude of M_Ks <~ -19.5 mag. This extends into the dwarf regime, 6 magnitudes below M_Ks*. The catalogue contains 390 objects, 235 of which are classified as likely or definite galaxies and 155 as candidate galaxies. The Ks-band luminosity function (LF) is constructed from the photometric sample, using a spectroscopic subsample to correct for fore- and background contamination. We fit a Schechter function with a characteristic magnitude of M_Ks* = -25.39 \pm 0.80 mag and faint-end slope of alpha = -1.26 \pm 0.10 to the data. The shape of the LF is similar to those found in previous determinations of the cluster LF, in both optical and near infrared. The Schechter parameters agree well with those of recent field LFs, suggesting that both the shape of the bright end and the faint end slope are relatively insensitive to environment., Comment: 18 pages, 6 figures, 8 tables (includes full photometric catalogue as appendix), accepted for publication in MNRAS

Rather than giving a complete overview on extragalactic Zone of Avoidance research, this paper will highlight some recent discoveries in the ZOA, such as new NIR to FIR observations (IRSF, Spitzer) of the most massive disk galaxy found to-date (HIZOA 0836-43), and deep multi-wavelength observations of a spiral galaxy WKK 6167 undergoing transformation while infalling along the Great Attractor Wall into the Norma cluster - reminiscent of similar incidences observed in two galaxies at higher redshifts (z ~ 0.2). While the recent systematic multi-wavelengths approaches to uncover the large-scale structure of galaxies across the ZOA have proven quite successful, in particular in the Great Attractor region, they lack the required depth to answer open questions with regard to our understanding of the dynamics in the Local Universe. The actual mass distribution is poorly understood and does not satisfactorily explain the observed peculiar velocity fields and the CMB dipole. We will present future HI survey strategies to be pursued with the South African SKA Pathfinder MeerKAT in the ZOA, that can - amongst others - resolve the long-standing Great Attractor/Shapley controversy, and determine at which distance range the cumulative peculiar motion of the Local Group flattens off and the Universe becomes homogeneous., Comment: To appear in "First Middle East-Africa Regional IAU Meeting (MEARIM)", ed. A. Hady, Cairo University Press, 8 pages, 3 figures (ps) one table (ps)

HIZOA J0836-43 is an extreme gas-rich ($M_{\rm{HI}}$=7.5$\times10^{10} M_{\sun}$) disk galaxy which lies hidden behind the strongly obscuring Vela region of the Milky Way. Utilizing observations from the {\it Spitzer Space Telescope}, we have found it to be a luminous infrared starburst galaxy with a star formation rate of $\sim 21 M_{\sun} \rm{yr^{-1}}$, arising from exceptionally strong molecular PAH emission ($L_{7.7\micron} = 1.50 \times 10^{9} L_{\odot}$) and far-infrared emission from cold dust. The galaxy exhibits a weak mid-infrared continuum compared to other starforming galaxies and U/LIRGs. This relative lack of emission from small grains suggests atypical interstellar medium conditions compared to other starbursts. We do not detect significant $[$Ne {\sc v}$]$ or $[$O {\sc iv}$]$, which implies an absent or very weak AGN. The galaxy possesses a prominent bulge of evolved stars and a stellar mass of 4.4($\pm$1.4)$\times10^{10} M_{\sun}$. With its plentiful gas supply and current star formation rate, a doubling of stellar mass would occur on a timescale of $\sim$2 Gyr. Compared to local galaxies, HIZOA J0836-43 appears to be a "scaled-up" spiral undergoing inside-out formation, possibly resembling stellar disk building processes at intermediate redshifts., Comment: 5 pages, 3 figures, 1 table; Accepted for publication in ApJL: August 25 2008. A version with full resolution figures is available at http://spider.ipac.caltech.edu/staff/jarrett/Cluver_ApJL.pdf

A detailed dynamical analysis of the nearby rich Norma cluster (ACO 3627) is presented. From radial velocities of 296 cluster members, we find a mean velocity of 4871 +/- 54 km/s and a velocity dispersion of 925 km/s. The mean velocity of the E/S0 population (4979 +/- 85 km/s) is offset with respect to that of the S/Irr population (4812 +/- 70 km/s) by `Delta' v = 164 km/s in the cluster rest frame. This offset increases towards the core of the cluster. The E/S0 population is free of any detectable substructure and appears relaxed. Its shape is clearly elongated with a position angle that is aligned along the dominant large-scale structures in this region, the so-called Norma wall. The central cD galaxy has a very large peculiar velocity of 561 km/s which is most probably related to an ongoing merger at the core of the cluster. The spiral/irregular galaxies reveal a large amount of substructure; two dynamically distinct subgroups within the overall spiral-population have been identified, located along the Norma wall elongation. The dynamical mass of the Norma cluster within its Abell radius is 1 - 1.1 x 10^15 h^-1_73 M_Sun. One of the cluster members, the spiral galaxy WKK 6176 which recently was observed to have a 70 kpc X-ray tail, reveals numerous striking low-brightness filaments pointing away from the cluster centre suggesting strong interaction with the intracluster medium., Comment: Sumbitted to MNRAS. 13 pages, 11 figures. Figures 6 and 10 reduced in resolution. Original available on request

We report on the discovery of two spiral galaxies located behind the southern Milky Way, within the least explored region of the Great Attractor. They lie at 317, -0.5 deg galactic, where obscuration from Milky Way stars and dust exceeds 13 to 15 mag of visual extinction. The galaxies were the most prominent of a set identified using mid-infrared images of the low-latitude (|b| < 1 deg) Spitzer Legacy program GLIMPSE. Follow-up HI radio observations reveal that both galaxies have redshifts that place them squarely in the Norma Wall of galaxies, which appears to extend diagonally across the Galactic Plane from Norma in the south to Centaurus & Vela in the north. We report on the near-infrared, mid-infrared and radio properties of these newly discovered galaxies, and discuss their context in the larger view of the Great Attractor. The work presented here demonstrates that mid-infrared surveys open up a new window to study galaxies in the Zone of Avoidance., Comment: 6 pages text; four color figures, two tables; to be published in the AJ, 2007, volume 133

The highly obscured radio-bright galaxy PKS1343-601 (l=309.7, b=+1.8) has been suspected to mark the centre of a hitherto unknown cluster in the Great Attractor region. As such it presents an ideal region for a search of galaxies in the near-infrared (NIR) and an in-depth study of their colours as a function of extinction. A visual search of a ~30 square-degree area centered on this radio galaxy on images of the NIR DENIS survey (IJK) revealed 83 galaxies (including two AGNs) and 39 possible candidates. Of these, 49 are also listed in the 2MASS Extended Source Catalog 2MASX. Taking the IRAS/DIRBE extinction values (Schlegel et al. 1998) at face value, the absorption in the optical (A_B) ranges from ~2m to over 100m across the Galactic Plane. Comparing the detections with other systematic surveys, we conclude that this search is highly complete up to the detection limits of the DENIS survey and certainly surpasses any automatic galaxy finding algorithm applied to crowded areas. The NIR galaxy colours from the 7" aperture were used as a probe to measure total Galactic extinction. A comparison with the IRAS/DIRBE Galactic reddening maps suggests that the IRAS/DIRBE values result in a slight overestimate of the true extinction at such low Galactic latitudes; the inferred extinction from the galaxy colours corresponds to about 87% of the IRAS/DIRBE extinctions. Although this determination still shows some scatter, it proves the usefulness of NIR surveys for calibrating the IRAS/DIRBE maps in the extinction range of 2m < A_B < 12m., Comment: 28 pages, 15 figures, submitted to A&A

We report the discovery of a very HI-massive disk galaxy, HIZOA J0836-43, at a velocity of v_hel = 10689 km/s, corresponding to a distance of 148 Mpc (assuming H_0=75 km/s/Mpc). It was found during the course of a systematic HI survey of the southern Zone of Avoidance (|b| < 5 deg) with the multibeam system at the 64m Parkes radio telescope. Follow-up observations with the Australia Telescope Compact Array (ATCA) reveal an extended HI disk. We derive an HI mass of 7.5 x 10^10 Msun. Using the HI radius, we estimate a total dynamical mass of 1.4 x 10^12 Msun, similar to the most massive known disk galaxies such as Malin 1. HIZOA J0836-43 lies deep in the Zone of Avoidance (l, b = 262.48 deg, -1.64 deg) where the optical extinction is very high, A_B = 9.8. However, in the near-infrared wavebands, where the extinction is considerably lower, HIZOA J0836-43 is clearly detected by both DENIS and 2MASS. Deep AAT near-infrared (Ks and H-band) images show that HIZOA J0836-43 is an inclined disk galaxy with a prominent bulge (scale length 2.5 arcsec or 1.7 kpc), and an extended disk (scale length 7 arcsec or 4.7 kpc) which can be traced along the major axis out to a radius of 20 arcsec or 13.4 kpc (at 20 mag/arcsec^2 in Ks). The HI disk is much more extended, having a radius of 66 kpc at 1 Msun/pc^2. Detections in the radio continuum at 1.4 GHz and at 60 micron (IRAS) are consistent with HIZOA J0836-43 forming stars at a rate of ~35 Msun/yr. We compare the properties of HIZOA J0836-43 with those of the most HI-massive galaxies currently known, UGC 4288, UGC 1752 and Malin 1, all of which are classified as giant low surface brightness galaxies., Comment: Accepted for publication in MNRAS, 17 pages, 11 figures, 7 tables, version with high-resolution figures available at: http://frodo.as.arizona.edu/~jdonley/massive/

To further our understanding of the Great Attractor (GA), we have undertaken a redshift survey using the 2dF on the AAT. Clusters and filaments in the GA region were targeted with 25 separate pointings resulting in approximately 2600 new redshifts. Targets included poorly studied X-ray clusters from the CIZA catalogue as well as the Cen-Crux and PKS 1343-601 clusters, both of which lie close to the classic GA centre. For nine clusters in the region, we report velocity distributions as well as virial and projected mass estimates. The virial mass of CIZA J1324.7-5736, now identified as a separate structure from the Cen-Crux cluster, is found to be ~3x10^14 M_sun, in good agreement with the X-ray inferred mass. In the PKS 1343-601 field, five redshifts are measured of which four are new. An analysis of redshifts from this survey, in combination with those from the literature, reveals the dominant structure in the GA region to be a large filament, which appears to extend from Abell S0639 (l=281\deg, b=+11\deg) to (l~5\deg, b~-50\deg), encompassing the Cen-Crux, CIZA J1324.7-5736, Norma and Pavo II clusters. Behind the Norma Cluster at cz~15000 km/s, the masses of four rich clusters are calculated. These clusters (Triangulum-Australis, Ara, CIZA J1514.6-4558 and CIZA J1410.4-4246) may contribute to a continued large-scale flow beyond the GA. The results of these observations will be incorporated into a subsequent analysis of the GA flow., Comment: 13 pages, 8 figures. Accepted for publication in MNRAS. High resolution versions of Fig. 4, 7 & 8 are available in the refereed publication

Deep J, H and Ks photometry of the low Galactic latitude Norma cluster has been obtained with the 1.4-m Infrared Survey Facility (IRSF) and with SOFI on the NTT. Together with spectroscopy taken at the Anglo-Australian Observatory using 2dF, the near-infrared Fundamental Plane of the Norma cluster will be used to determine the distance to this cluster and to assess its location within the Great Attractor overdensity. Potential systematic uncertainties related to the determination of peculiar velocities in the Zone of Avoidance are discussed in some detail. In particular the effects (uncertainties, systematics and scatter) of extinction and star-crowding on the derived magnitudes at low latitudes are investigated in great detail. We present a first look at the emerging Ks-band Fundamental Plane of the Norma cluster. We expect an uncertainty of ~ 3% (~ 150 km/s at the distance of the Norma cluster) in our final Fundamental Plane distance estimate based on 76 galaxies., Comment: 11 pages, 4 figures, to appear in 'Nearby Large-Scale Structures and the Zone of Avoidance', eds. A.P. Fairall and P.A. Woudt (ASP Conf. Ser)

We present the results of the northern extension of the HI Parkes Zone of Avoidance Survey, a blind HI survey utilizing the multibeam receiver on the Parkes 64-m telescope. In the two regions studied here, l=36 to 52 deg. and l=196 to 212 deg., |b|<5 deg., we have detected 77 HI galaxies, twenty of which have been previously detected in HI. The survey has a median rms noise of 6.0 mJy/beam and is complete to a mean flux density of 22 mJy. We have searched for multiwavelength counterparts to the 77 galaxies detected here: 19, 27, and 11 have a likely optical, 2MASS, and IRAS cataloged counterpart, respectively. A further 16 galaxies have likely visible counterparts on the Digitized Sky Survey. The detection of these 77 galaxies allows a closer inspection of the large-scale structures in these regions. We see several filaments crossing the Galactic plane, one of which appears to be the continuation of a sine-wave like feature that can be traced across the whole southern sky. An analysis of the HI mass function suggests that the regions studied here may be underdense. One particularly noteworthy galaxy is HIZOA J0630+08 (l,b = 203 deg., -0.9 deg.) with a velocity of 367 km/s. We suggest that it belongs to the nearby Orion Group which includes a small number of dwarf galaxies. The newly detected galaxies improve our understanding of the properties of several voids, such as the Orion, Gemini, and Canis Major Voids., Comment: 18 pages, 15 figures, 6 tables, accepted for publication in The Astronomical Journal (January 2005 issue)

(abridged) We present the HIPASS Bright Galaxy Catalog (BGC) which contains the 1000 HI-brightest galaxies in the southern sky as obtained from the HI Parkes All-Sky Survey (HIPASS). The selection of the brightest sources is based on their HI peak flux density (Speak > 116 mJy) as measured from the spatially integrated HIPASS spectrum. The derived HI masses range from about 10^7 to 4 x 10^10 Msun. While the BGC (z < 0.03) is complete in Speak, only a subset of about 500 sources can be considered complete in integrated HI flux density (FHI > 25 JY km/s). The HIPASS BGC contains a total of 158 new redshifts and yields no evidence for a population of "free-floating" intergalactic HI clouds without associated optical counterparts. HIPASS provides a clear view of the local large-scale structure. The dominant features in the sky distribution of the BGC are the Supergalactic Plane and the Local Void. In addition, one can clearly see the Centaurus Wall which connects via the Hydra and Antlia clusters to the Puppis filament. Some previously hardly noticed galaxy groups stand out quite distinctively in the HI sky distribution. Several new structures are seen for the first time, not only behind the Milky Way., Comment: AJ, accepted (scheduled for publication in July 2004). Latex, 46 pages. The HIPASS BGC paper, figures, tables, HI spectra and further infromation are available at http://www.atnf.csiro.au/research/multibeam/HIPASS-BGC

A first analysis of a deep blind HI survey covering the southern Zone of Avoidance plus an extension towards the north (196 < l < 52 deg) obtained with the Multibeam receiver at the 64m Parkes telescope reveals slightly over a thousand galaxies within the latitude completeness limit of |b| < 5deg. The characteristics and the uncovered large-scale structures of this survey are described, in particular the prominence of the Norma Supercluster, the possible cluster around PKS 1343-601 (both in the Great Attractor region), as well as the Local Void and the clustering in the Puppis region. In this blind HI survey, HIZOA J0836-43, one of the most massive spiral galaxies known to date was discovered (M(HI) = 7.3 10^10 Msun M(tot) = 1.1 10^12 Msun; Ho = 75 km/s/Mpc). Although of similar mass as Malin 1-like objects, this galaxy does not share their typical low-surface brightness properties but seems an exceptionally massive but normal, high-surface brightness, star-forming galaxy., Comment: 8 pages, 6 encapulated ps-figures, uses newpasp.sty, to appear in IAU Symp. 216, Maps of the Cosmos, ASP, eds. M. Colless & L. Staveley-Smith

We have obtained VLA and optical follow-up observations of the low-velocity H I source HIZSS 3 discovered by Henning et al. (2000) and Rivers (2000) in a survey for nearby galaxies hidden by the disk of the Milky Way. Its radio characteristics are consistent with this being a nearby (~1.8 Mpc) low-mass dwarf irregular galaxy (dIm). Our optical imaging failed to reveal a resolved stellar population, but did detect an extended H-alpha emission region. The location of the H-alpha source is coincident with a partially-resolved H I cloud in the 21-cm map. Spectroscopy confirms that the H$\alpha$ source has a similar radial velocity to that of the H I emission at this location, and thus we have identified an optical counterpart. The H$\alpha$ emission (100 pc in diameter and with a luminosity of $1.4\times10^{38}$ ergs s$^{-1}$) is characteristic of a single H II region containing a modest population of OB stars. The galaxy's radial velocity and distance from the solar apex suggests that it is not a Local Group member, although a more accurate distance is needed to be certain. The properties of HIZSS 3 are comparable to those of GR 8, a nearby dIm with a modest amount of current star formation. Further observations are needed to characterize its stellar population, determine the chemical abundances, and obtain a more reliable distance estimate., Comment: Scheduled for the November 2003 issue of the Astronomical Journal

We present a new accurate measurement of the HI mass function of galaxies from the HIPASS Bright Galaxy Catalog, a sample of 1000 galaxies with the highest HI peak flux densities in the southern hemisphere (Koribalski et al. 2003). This sample spans nearly four orders of magnitude in HI mass (from log M_HI/M_sun=6.8 to 10.6, H0=75) and is the largest sample of HI selected galaxies to date. We develop a bivariate maximum likelihood technique to measure the space density of galaxies, and show that this is a robust method, insensitive to the effects of large scale structure. The resulting HI mass function can be fitted satisfactorily with a Schechter function with faint-end slope alpha=-1.30. This slope is found to be dependent on morphological type, with later type galaxies giving steeper slopes. We extensively test various effects that potentially bias the determination of the HI mass function, including peculiar motions of galaxies, large scale structure, selection bias, and inclination effects, and quantify these biases. The large sample of galaxies enables an accurate measurement of the cosmological mass density of neutral gas: Omega_HI=(3.8 +/- 0.6) x 10^{-4}. Low surface brightness galaxies contribute only 15% to this value, consistent with previous findings., Comment: accepted for publication in Astronomical Journal, 16 pages, including 17 figures. Corrected typos and references

The HI Parkes All-Sky Survey (HIPASS) is a blind 21-cm survey for extragalactic neutral hydrogen, covering the whole southern sky. The HIPASS Bright Galaxy Catalog (BGC; Koribalski et al. 2002) is a subset of HIPASS and contains the 1000 HI-brightest (peak flux density) galaxies. Here we present the 138 HIPASS BGC galaxies, which had no redshift measured prior to the Parkes multibeam HI surveys. Of the 138 galaxies, 87 are newly cataloged. Newly cataloged is defined as no optical (or infrared) counterpart in the NASA/IPAC Extragalactic Database. Using the Digitized Sky Survey we identify optical counterparts for almost half of the newly cataloged galaxies, which are typically of irregular or magellanic morphological type. Several HI sources appear to be associated with compact groups or pairs of galaxies rather than an individual galaxy. The majority (57) of the newly cataloged galaxies lie within ten degrees of the Galactic Plane and are missing from optical surveys due to confusion with stars or dust extinction. This sample also includes newly cataloged galaxies first discovered in the HI shallow survey of the Zone-of-Avoidance (Henning et al. 2000). The other 30 newly cataloged galaxies escaped detection due to their low surface brightness or optical compactness. Only one of these, HIPASS J0546-68, has no obvious optical counterpart as it is obscured by the Large Magellanic Cloud. We find that the newly cataloged galaxies with |b| > 10 are generally lower in HI mass and narrower in velocity width compared with the total HIPASS BGC. In contrast, newly cataloged galaxies behind the Milky Way are found to be statistically similar to the entire HIPASS BGC. In addition to these galaxies, the HIPASS BGC contains four previously unknown HI clouds., Comment: 39 pages including 14 figures, to appear in the Oct 2002 issue of AJ

ATCA 21 cm HI observations of the rich galaxy cluster ACO 3627 in the Great Attractor region are presented. Three fields of 30' diameter located within one Abell radius of ACO 3627 were observed with a resolution of 15'' and an rms noise of \sim 1 mJy/beam. Only two galaxies were detected in these fields. We compare their HI distribution to new optical R-band images and discuss their velocity fields. The first galaxy is a gas-rich unperturbed spiral whereas the second shows a peculiar HI distribution. The estimated 3-sigma HI mass limit of our observations is \sim 7 x 10^8 M_{\odot} for a line width of 150 km s^{-1}. The non-detection of a considerable number of luminous spiral galaxies indicates that the spiral galaxies are HI deficient. The low detection rate is comparable to the HI deficient Coma cluster (Bravo-Alfaro et al. 2000). ACO 3627 is a bright X-ray cluster. We therefore suspect that ram pressure stripping is responsible for the HI deficiency of the bright cluster spirals., Comment: 9 pages with 7 figures; A&A, in press

We discuss the possibilities of extragalactic large-scale studies behind the Zone of Avoidance (ZOA) using complementary multi-wavelength data from optical, systematic blind HI, and near-infrared (NIR) surveys. Applying these data to the NIR Tully-Fisher relation permits the mapping of the peculiar velocity field across the ZOA. Here, we present results of a comparison of galaxies identified in the rich low-latitude cluster Abell 3627 in the B-band with NIR (DENIS) data, and cross-identifications of galaxies detected with the blind Parkes HI Multibeam survey with NIR data - many of which are optically invisible., Comment: 9 pages, 5 figures, Latex using newpasp.sty; to appear in Mapping the Hidden Univese, ASP Conf. Ser., eds. R.C. Kraan-Korteweg, P.A. Henning, H. Andernach