A. Schröder

VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way

Original article can be found at: http://www.sciencedirect.com/science/journal/13841076 Copyright Elsevier B.V.

The 1000 brightest hipass galaxies: The HI mass function and Omega(HI)

We present a new, accurate measurement of the H I mass function of galaxies from the HIPASS Bright Galaxy Catalog, a sample of 1000 galaxies with the highest H I peak flux densities in the southern (delta<0D) hemisphere. This sample spans nearly 4 orders of magnitude in H I mass [ log (M-H I/M-O) + 2 log h(75)=6.8-10.6] and is the largest sample of H I-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 H I mass function can be fitted satisfactorily with a Schechter function with faint-end slope α=-1.30. This slope is found to be dependent on morphological type, with late-type galaxies giving steeper slopes. We extensively test various effects that potentially bias the determination of the H I mass function, including peculiar motions of galaxies, large-scale structure, selection bias, and inclination effects, and we quantify these biases. The large sample of galaxies enables an accurate measurement of the cosmological mass density of neutral gas: U(H) I=(3.8P0.6)x10(-4) h(75)(-1). Low surface brightness galaxies contribute only similar to15% to this value, consistent with previous findings.

The 1000 brightest HIPASS galaxies: The H I mass function and ω

We present a new, accurate measurement of the H I mass function of galaxies from the HIPASS Bright Galaxy Catalog, a sample of 1000 galaxies with the highest H I peak flux densities in the southern (delta<0D) hemisphere. This sample spans nearly 4 orders of magnitude in H I mass [ log (M-H I/M-O) + 2 log h(75)=6.8-10.6] and is the largest sample of H I-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 H I mass function can be fitted satisfactorily with a Schechter function with faint-end slope α=-1.30. This slope is found to be dependent on morphological type, with late-type galaxies giving steeper slopes. We extensively test various effects that potentially bias the determination of the H I mass function, including peculiar motions of galaxies, large-scale structure, selection bias, and inclination effects, and we quantify these biases. The large sample of galaxies enables an accurate measurement of the cosmological mass density of neutral gas: U(H) I=(3.8P0.6)x10(-4) h(75)(-1). Low surface brightness galaxies contribute only similar to15% to this value, consistent with previous findings.

H I-bright Galaxies in the Southern Zone of Avoidance

A blind survey for H I–bright galaxies in the southern zone of avoidance (212° ≤ l ≤ 36°, |b| ≤ 5°) has been made with the 21 cm multibeam receiver on the Parkes 64 m radio telescope. The survey, sensitive to normal spiral galaxies to a distance of ~40 Mpc and more nearby dwarfs, detected 110 galaxies. Of these, 67 have no counterparts cataloged in the NASA/IPAC Extragalactic Database. In general, the uncataloged galaxies lie behind thicker obscuration than do the cataloged objects. All the newly discovered galaxies have H I flux integrals that are more than an order of magnitude lower than those of the Circinus galaxy. The survey recovers the Puppis Cluster and foreground group, and the Local Void remains empty. The H I mass function derived for the sample is satisfactorily fitted by a Schechter function with parameters α = 1.51 ± 0.12, Φ* = 0.006 ± 0.003, and log M* = 9.7 ± 0.10.

THE H I PARKES ZONE OF AVOIDANCE SURVEY: THE NORTHERN EXTENSION

We present the results of the northern extension of the H I Parkes Zone of Avoidance Survey, a blind H I survey utilizing the multibeam receiver on the Parkes 64 m telescope. In the two regions studied here, l = 36°–52° and l = 196°–212°, |b| ≤ 5°, we have detected 77 H I galaxies, 20 of which have been previously detected in H I. The survey has a median rms noise of 6.0 mJy beam-1 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 H I mass function suggests that the regions studied here may be underdense. One particularly noteworthy galaxy is HIZOA J0630+08 (l, b = 203°, - 09) with a velocity of 367 ± 1 km s-1. 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.

The 1000 brightest HIPASS galaxies: newly cataloged galaxies

The H I 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) is a subset of HIPASS and contains the 1000 H I brightest (peak flux density) galaxies. Here we present the 138 HIPASS BGC galaxies that had no redshift measured prior to the Parkes multibeam H I surveys. Of the 138 galaxies, 87 are newly cataloged. Newly cataloged is defined as having 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 H I 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 10degrees of the Galactic plane and are missing from optical surveys as a result of confusion with stars or dust extinction. This sample also includes newly cataloged galaxies first discovered by Henning et al. in the H I shallow survey of the zone of avoidance. The other 30 newly cataloged galaxies escaped detection because of 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->10degrees are generally lower in H I 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 H I clouds.

A massive spiral galaxy in the Zone of Avoidance

We report the discovery of a very H i-massive disk galaxy, HIZOA J0836{43, at a velocity of vhel = 10689 km s 1 , corresponding to a distance of 148 Mpc (assuming H0 = 75 km s 1 Mpc 1 ). It was found during the course of a systematic H i survey of the southern Zone of Avoidance (jbj 5 ) with the multibeam system at the 64 m Parkes radio telescope. Follow-up observations with the Australia Telescope Compact Array (ATCA) reveal an extended H i disk. We derive an H i mass of 7:5 10 10 M . Using the H i radius, we estimate a total dynamical mass of 1:4 10 12 M , similar to the most massive known disk galaxies such as Malin 1. HIZOA J0836{43 lies deep in the Zone of Avoidance (‘; b = 262: 48; 1: 64) where the optical extinction is very high, AB = 9: m 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 00 or 1.7 kpc), and an extended disk (scale length 7 00 or 4.7 kpc) which can be traced along the major axis out to a radius of 20 00 or 13.4 kpc (at 20 mag arcsec 2 in Ks). The H i disk is much more extended, having a radius of 66 kpc at 1 M pc 2 . Detections in the radio continuum at 1.4 GHz and at 60 m (IRAS) are consistent with HIZOA J0836{43 forming stars at a rate of 35 M yr 1 . We compare the properties of HIZOA J0836{43 with those of the most H i-massive galaxies currently known, UGC 4288, UGC 1752 and Malin 1, all of which are classied as giant low surface brightness galaxies.

A Blind H I Survey for Galaxies in the Zone of Avoidance, 308? ? l ? 332?

We report on a blind neutral hydrogen survey for galaxies using the 21 cm multibeam receiver on the Parkes 64 m telescope. The surveyed region covers |b| ≤ 5° in the zone of avoidance (ZOA) from Galactic longitude 308° to 332°. The survey represents the first phase of a blind H I survey covering the southern ZOA (l = 212° to 36°). We have detected H I in 42 galaxies above a 3 σ limit of 60 mJy. The galaxies detected in this survey have velocities out to 6000 km s-1 and H I masses in the range 4 × 107 to 3 × 1010M⊙ (h). Only eight of the 42 galaxies have velocities previously measured. A further nine galaxies appear to have optical counterparts in the Woudts 1998 catalog. In total, 16 of the galaxies appear to be associated with IRAS sources, although only three of these are without optical counterparts. The estimated median extinction for the 20 galaxies with optical or IR counterparts is AB = 3.8 mag. For the 22 galaxies with no counterparts, the estimated median extinction is AB = 5.6 mag. The distribution of galaxies is suggestive of a connection between the Centaurus supercluster above the Galactic plane and the Pavo-Indus supercluster beneath the plane. No previously hidden concentrations of galaxies were found.

The highly obscured region around PKS 1343 – 601 - I. Galactic interstellar extinctions using DENIS galaxy colours

The highly obscured radio-bright galaxy PKS 1343 – 601 at Galactic coordinates of

The neutral hydrogen content of Fornax cluster galaxies

(l,b) = (309\fdg7, +1\fdg8