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 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 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 4.1. Radio continuum and molecular gas in the Galactic center: large-scale structures

1998 ◽  
Vol 184 ◽  
pp. 161-168
Author(s):  
Yoshiaki Sofue
Keyword(s):  
Radio Emission ◽  
Linear Polarization ◽  
Large Scale ◽  
Galactic Center ◽  
Thermal Emission ◽  
Radio Continuum ◽  
Molecular Gas ◽  
Large Scale Structures ◽  
Almost Everywhere ◽  
Scale Structures

The radio emission from the Galactic Center is a mixture of thermal (free-free) and non-thermal (synchrotron) emissions (Fig. 1a). However, the spectral index in the central 3° region is flat almost everywhere (Sofue 1985), even in regions where strong linear polarization is detected. Therefore, a flat spectrum observed near the galactic center can no longer be taken as an indicator of thermal emission.

scholarly journals Detecting shocked intergalactic gas with X-ray and radio observations

2019 ◽  
Vol 627 ◽  
pp. A5 ◽  
Author(s):  
F. Vazza ◽  
S. Ettori ◽  
M. Roncarelli ◽  
M. Angelinelli ◽  
M. Brüggen ◽  
...  
Keyword(s):  
Large Scale ◽  
Intergalactic Medium ◽  
Thermal Emission ◽  
Intergalactic Gas ◽  
Radio Observations ◽  
X Ray ◽  
Large Scale Structures ◽  
Hot Gas ◽  
Scale Structures ◽  
Radio Band

Detecting the thermal and non-thermal emission from the shocked cosmic gas surrounding large-scale structures represents a challenge for observations, as well as a unique window into the physics of the warm-hot intergalactic medium. In this work, we present synthetic radio and X-ray surveys of large cosmological simulations in order to assess the chances of jointly detecting the cosmic web in both frequency ranges. We then propose best observing strategies tailored for existing (LOFAR, MWA, and XMM) or future instruments (SKA-LOW and SKA-MID, Athena, and eROSITA). We find that the most promising targets are the extreme peripheries of galaxy clusters in an early merging stage, where the merger causes the fast compression of warm-hot gas onto the virial region. By taking advantage of a detection in the radio band, future deep X-ray observations will probe this gas in emission, and help us to study plasma conditions in the dynamic warm-hot intergalactic medium with unprecedented detail.

Super-Large-Scale Structures in the Sloan Digital Sky Survey

2006 ◽  
Vol 6 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Xin-Fa Deng ◽  
Yi-Qing Chen ◽  
Qun Zhang ◽  
Ji-Zhou He
Keyword(s):  
Large Scale ◽  
Sloan Digital Sky Survey ◽  
Large Scale Structures ◽  
Sky Survey ◽  
Scale Structures

scholarly journals On the Environments of Giant Radio Galaxies

2021 ◽  
Author(s):  
Ting-Wen Lan ◽  
J Xavier Prochaska
Keyword(s):  
Large Scale ◽  
Radio Galaxies ◽  
Sloan Digital Sky Survey ◽  
Host Galaxies ◽  
Homogeneous Sample ◽  
Large Scale Structures ◽  
Radio Jets ◽  
Sky Survey ◽  
Scale Structures ◽  
Control Samples

Abstract We test the hypothesis that environments play a key role in enabling the growth of enormous radio structures spanning more than 700 kpc, an extreme population of radio galaxies called giant radio galaxies (GRGs). To achieve this, we explore (1) the relationships between the occurrence of GRGs and the surface number density of surrounding galaxies, including satellite galaxies and galaxies from neighboring halos, as well as (2) the GRG locations towards large-scale structures. The analysis is done by making use of a homogeneous sample of 110 GRGs detected from the LOFAR Two-metre Sky Survey in combination with photometric galaxies from the DESI Legacy Imaging Surveys and a large-scale filament catalog from the Sloan Digital Sky Survey. Our results show that the properties of galaxies around GRGs are similar with that around the two control samples, consisting of galaxies with optical colors and luminosity matched to the properties of the GRG host galaxies. Additionally, the properties of surrounding galaxies depend on neither their relative positions to the radio jet/lobe structures nor the sizes of GRGs. We also find that the locations of GRGs and the control samples with respect to the nearby large-scale structures are consistent with each other. These results demonstrate that there is no correlation between the GRG properties and their environments traced by stars, indicating that external galaxy environments are not the primary cause of the large sizes of the radio structures. Finally, regarding radio feedback, we show that the fraction of blue satellites does not correlate with the GRG properties, suggesting that the current epoch of radio jets have minimal influence on the nature of their surrounding galaxies.

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| &lt; 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 Identification of Extremely Large Scale Structures in SDSS-III

2014 ◽  
Vol 11 (S308) ◽  
pp. 299-300
Author(s):  
Shishir Sankhyayan ◽  
J. Bagchi ◽  
P. Sarkar ◽  
V. Sahni ◽  
J. Jacob
Keyword(s):  
Large Scale ◽  
Sloan Digital Sky Survey ◽  
Limited Sample ◽  
Large Scale Structures ◽  
Large Structures ◽  
Density Peaks ◽  
Redshift Surveys ◽  
Sky Survey ◽  
Scale Structures ◽  
The Universe

AbstractWe have initiated the search and detailed study of large scale structures present in the universe using galaxy redshift surveys. In this process, we take the volume-limited sample of galaxies from Sloan Digital Sky Survey III and find very large structures even beyond the redshift of 0.2. One of the structures is even greater than 600 Mpc which raises a question on the homogeneity scale of the universe. The shapes of voids-structures (adjacent to each other) seem to be correlated, which supports the physical existence of the observed structures. The other observational supports include galaxy clusters' and QSO distribution's correlation with the density peaks of the volume limited sample of galaxies.

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