scholarly journals EZOA – a catalogue of EBHIS H i-detected galaxies in the northern Zone of Avoidance

2019 ◽  
Vol 489 (2) ◽  
pp. 2907-2922 ◽  
Author(s):  
A C Schröder ◽  
L Flöer ◽  
B Winkel ◽  
J Kerp
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Dwarf Galaxies ◽  
High Rate ◽  
Infrared Images ◽  
Large Scale Structures ◽  
The Past ◽  
Northern Zone ◽  
Scale Structures ◽  
Zone Of Avoidance

ABSTRACT We present a catalogue of galaxies in the northern Zone of Avoidance (ZoA), extracted from the shallow version of the blind H i survey with the Effelsberg 100 m radio telescope, EBHIS, that has a sensitivity of 23 mJy beam−1 at 10.24 km s−1 velocity resolution. The catalogue comprises 170 detections in the region δ ≥ −5° and |b| < 6°. About a third of the detections (N = 67) have not been previously recorded in H i. While 29 detections have no discernible counterpart at any wavelength other than H i, 48 detections (28 per cent) have a counterpart visible on optical or near-infrared images but are not recorded as such in the literature. New H i detections were found as close as 7.5 Mpc (EZOA J2120+45), and at the edge of the Local Volume, at 10.1 Mpc, we have found two previously unknown dwarf galaxies (EZOA J0506+31 and EZOA J0301+56). Existing large-scale structures crossing the northern ZoA have been established more firmly by the new detections, with the possibility of new filaments. We conclude that the high rate of 39 per cent new H i detections in the northern ZoA, which has been extensively surveyed with targeted observations in the past, proves the power of blind H i surveys. The full EBHIS survey, which will cover the full northern sky with a sensitivity comparable to the HIPASS survey of the southern sky, is expected to add many new detections and uncover new structures in the northern ZoA.

scholarly journals Large Scale Structure in the Local Universe — The 2MASS Galaxy Catalog

2004 ◽  
Vol 21 (4) ◽  
pp. 396-403 ◽  
Author(s):  
Thomas Jarrett
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Local Universe ◽  
Extended Source ◽  
Large Scale Structures ◽  
Photometric Redshift ◽  
Sky Survey ◽  
Nearby Galaxies ◽  
Scale Structures ◽  
Zone Of Avoidance

AbstractUsing twin ground-based telescopes, the Two-Micron All Sky Survey (2MASS) scanned both equatorial hemispheres, detecting more than 500 million stars and resolving more than 1.5 million galaxies in the near-infrared (1–2.2 μm) bands. The Extended Source Catalog (XSC) embodies both photometric and astrometric whole sky uniformity, revealing large scale structures in the local Universe and extending our view into the Milky Way's dust-obscured ‘Zone of Avoidance’. The XSC represents a uniquely unbiased sample of nearby galaxies, particularly sensitive to the underlying, dominant, stellar mass component of galaxies. The basic properties of the XSC, including photometric sensitivity, source counts, and spatial distribution, are presented here. Finally, we employ a photometric redshift technique to add depth to the spatial maps, reconstructing the cosmic web of superclusters spanning the sky.

scholarly journals Overview of Uncovered and Suspected Large-scale Structures behind the Milky Way

1999 ◽  
Vol 16 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Renée C. Kraan-Korteweg ◽  
Patrick A. Woudt
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Milky Way ◽  
Far Infrared ◽  
Observational Evidence ◽  
Large Scale Structures ◽  
Galaxy Distribution ◽  
Wide Range ◽  
Scale Structures ◽  
Zone Of Avoidance

AbstractVarious dynamically important extragalactic large-scale structures in the local Universe lie behind the Milky Way. Most of these structures (predicted and unexpected) have only recently been made ‘visible’ through dedicated deep surveys at various wavelengths. The wide range of observational searches (optical, near infrared, far infrared, radio and X-ray) for galaxies in the Zone of Avoidance (ZOA) will be reviewed and the uncovered and suspected large-scale structures summarised. Particular emphasis is given to the Great Attractor region where the existence of yet another cluster is suspected (Woudt 1998). Predictions from reconstructions of the density field in the ZOA are discussed and compared with observational evidence. Although no major structures are predicted out to about v ≲ 10,000 km s−1 for which no observational evidence exists, the comparison between reconstructed density fields and the observed galaxy distribution remain important as they allow derivations of the density and biasing parameters.

scholarly journals Galaxy Formation and Large-Scale Structures in a Two-Component Dark Matter Scenario

1988 ◽  
Vol 130 ◽  
pp. 427-428
Author(s):  
Masayuki Umemura
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Large Scale ◽  
Dwarf Galaxies ◽  
Large Scale Structures ◽  
Two Component ◽  
Scale Structures

A universe dominated by both hot (HDM) and cold dark matter (CDM) is proposed. In this context, the new features for the formation of dwarf galaxies, Lyα clouds, galaxies, and large-scale structures are presented.

scholarly journals An Obscured Galaxy Redshift Survey with FLAIR

1997 ◽  
Vol 14 (1) ◽  
pp. 126-126 ◽  
Author(s):  
K. Wakamatsu ◽  
M. Malkan ◽  
Q. A. Parker ◽  
H. Karoji
Keyword(s):  
Large Scale ◽  
Wall Structure ◽  
Galactic Centre ◽  
Large Scale Structures ◽  
Sky Survey ◽  
Centre Region ◽  
Redshift Survey ◽  
Galaxy Redshift ◽  
Scale Structures ◽  
Zone Of Avoidance

A problem for studies of large scale structures in nearby space (cz < 10,000 km s-1) is the presence of the Zone of Avoidance which is so large and wide on the sky that potentially important clusters and voids remain undetected. A prime example was the Ophiuchus cluster discovered by Wakamatsu and Malkan (1981) as a heavily obscured cD cluster close to the Galactic centre region (l = 0·5°, b = +9·5°). It is the second brightest X-ray cluster after Perseus. A hidden galaxy survey was performed by visually searching ESO/SERC Sky Survey (R and J) copy films of the region centred at l = 355°, b = +10° finding more than 4000 galaxies in six fields. Several irregular clusters adjacent to Ophiuchus were found forming a supercluster which may be connected to the Hercules supercluster by a wall structure parallel to the local supergalactic plane (Wakamatsu et al. 1994). In front of this supercluster, an 'Ophiuchus Void' is suggested (cz = 4,500 km s-1). The Ophiuchus supercluster at cz = 8,500 km s-1 is similar to the Hercules supercluster (cz = 11,000 km s-1), and extends north toward the latter supercluster.

scholarly journals A New 1.4 GHz Radio Continuum Map of the Sky South of Declination +25°

2014 ◽  
Vol 31 ◽  
Author(s):  
Mark R. Calabretta ◽  
Lister Staveley-Smith ◽  
David G. Barnes
Keyword(s):  
Large Scale ◽  
Thermal Emission ◽  
High Sensitivity ◽  
Radio Continuum ◽  
Archival Data ◽  
Large Scale Structures ◽  
Low Level ◽  
Sky Survey ◽  
Scale Structures ◽  
Zone Of Avoidance

AbstractArchival data from the HI Parkes All-Sky Survey (HIPASS) and the HI Zone of Avoidance (HIZOA) survey have been carefully reprocessed into a new 1.4 GHz continuum map of the sky south of δ = +25°. The wide sky coverage, high sensitivity of 40 mK (limited by confusion), resolution of 14.4 arcmin (compared to 51 arcmin for the Haslam et al. 408 MHz and 35 arcmin for the Reich et al. 1.4 GHz surveys), and low level of artefacts make this map ideal for numerous studies, including: merging into interferometer maps to complete large-scale structures; decomposition of thermal and non-thermal emission components from Galactic and extragalactic sources; and comparison of emission regions with other frequencies. The new map is available for download.

scholarly journals The Universe Behind the Southern Milky Way

2005 ◽  
Vol 216 ◽  
pp. 203-210 ◽  
Author(s):  
Renée C. Kraan-Korteweg ◽  
Lister Staveley-Smith ◽  
Jennifer Donley ◽  
Bärbel Koribalski ◽  
Patricia A. Henning
Keyword(s):  
Surface Brightness ◽  
Large Scale ◽  
High Surface ◽  
Star Forming ◽  
Large Scale Structures ◽  
The North ◽  
Low Surface Brightness ◽  
Scale Structures ◽  
Zone Of Avoidance ◽  
The Universe

A first analysis of a deep blind HI survey covering the southern Zone of Avoidance plus an extension towards the north (196† ≤ ℓ ≤ 52†) obtained with the Multibeam receiver at the 64-m Parkes telescope reveals slightly over a thousand galaxies within the latitude completeness limit of |b| ≤ 5†. 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 was discovered, one of the most massive spiral galaxies known to date (MHI = 7.3 × 1010 M⊙, MT = 1.1 × 1012 M⊙; H0 = 75 km/s/Mpc). Although of similar mass to 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.

scholarly journals First Results from the HI Parkes Zone of Avoidance Survey

1999 ◽  
Vol 171 ◽  
pp. 331-333
Author(s):  
P.A. Henning ◽  
L. Staveley-Smith ◽  
R.C. Kraan-Korteweg ◽  
E.M. Sadler
Keyword(s):  
Large Scale ◽  
Milky Way ◽  
Large Scale Structures ◽  
First Results ◽  
Nearby Galaxies ◽  
Scale Structures ◽  
Zone Of Avoidance ◽  
Blind Search

AbstractThe HI Parkes Zone of Avoidance Survey is a 21 cm blind search with the multibeam receiver on the 64-m radiotelescope, looking for galaxies hidden behind the southern Milky Way. The first phase of the survey has uncovered 107 galaxies, two-thirds of which were previously unknown. The addition of these galaxies to existing extragalactic catalogs allows the connectivity of large-scale structures across the Zone of Avoidance within 3500 km s−1 to become evident. No nearby hidden “Andromeda-class” object was uncovered. Our census of the most dynamically important HI-bearing nearby galaxies is now complete, at least for those objects whose HI profiles are not totally buried in the Galactic HI signal. The full survey is ongoing, and is expected to produce a catalog of thousands of objects when it is finished.

Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda
Keyword(s):  
Image Processing ◽  
Large Scale ◽  
Harvard College ◽  
Oak Ridge ◽  
Large Scale Structures ◽  
Short Period Comet ◽  
Short Period ◽  
Scale Structures ◽  
Harvard College Observatory ◽  
Period Comet

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.

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