scholarly journals Radio Sources in the 2dF Galaxy Redshift Survey I. Radio Source Populations

1999 ◽  
Vol 16 (3) ◽  
pp. 247-256 ◽  
Author(s):  
Elaine M. Sadler ◽  
V. J. McIntyre ◽  
C. A. Jackson ◽  
R. D. Cannon
Keyword(s):  
Radio Galaxy ◽  
Radio Continuum ◽  
Radio Sources ◽  
Star Forming ◽  
Sky Survey ◽  
Homogeneous Set ◽  
First Results ◽  
Redshift Survey ◽  
Galaxy Redshift ◽  
Source Populations

AbstractWe present the first results from a study of the radio continuum properties of galaxies in the 2dF Galaxy Redshift Survey, (2dFGRS) based on thirty 2dF fields covering a total area of about 100 deg2. About 1·5% of galaxies with bJ < 19·4 mag. are detected as radio continuum sources in the NRAO VLA Sky Survey (NVSS). Of these, roughly 40% are star-forming galaxies and 60% are active galaxies (mostly low-power radio galaxies and a few Seyferts). The combination of 2dFGRS and NVSS will eventually yield a homogeneous set of around 4000 radio-galaxy spectra, which will be a powerful tool for studying the distribution and evolution of both AGN and starburst galaxies out to z ∼ 0·3.

Mapping the Local and Distant Universe with SUMSS

2005 ◽  
Vol 216 ◽  
pp. 211-218
Author(s):  
Elaine M. Sadler ◽  
Richard W. Hunstead ◽  
Thomas Mauch ◽  
Duncan Campbell-Wilson ◽  
Carole A. Jackson ◽  
...  
Keyword(s):  
Radio Source ◽  
Radio Galaxies ◽  
Radio Continuum ◽  
Space Distribution ◽  
Local Universe ◽  
Star Forming ◽  
Sky Survey ◽  
First Results ◽  
Redshift Survey ◽  
Galaxy Redshift

The Sydney University Molonglo Sky Survey (SUMSS) is a radio continuum imaging survey of the southern sky at 843 MHz, with similar sensitivity and resolution to the northern NRAO VLA Sky Survey (NVSS). We have combined radio data from SUMSS and NVSS with optical spectra from the 2dF Galaxy Redshift Survey and 6dF Galaxy Survey to study the space distribution and properties of both AGN and star-forming galaxies in the local universe (redshift range 0 < z < 0.3). We also discuss new results on radio-source clustering in the more distant universe (z ∼ 1) and present the first results from a search for the most distant (z > 3) southern radio galaxies.

scholarly journals Radio sources in the 2dF Galaxy Redshift Survey - II. Local radio luminosity functions for AGN and star-forming galaxies at 1.4 GHz

2002 ◽  
Vol 329 (1) ◽  
pp. 227-245 ◽  
Author(s):  
Elaine M. Sadler ◽  
Carole A. Jackson ◽  
Russell D. Cannon ◽  
Vincent J. McIntyre ◽  
Tara Murphy ◽  
...  
Keyword(s):  
Radio Sources ◽  
Radio Luminosity ◽  
Star Forming ◽  
Luminosity Functions ◽  
Redshift Survey ◽  
Galaxy Redshift ◽  
Local Radio

scholarly journals Probing the Redshift Desert Using the Gemini Deep Deep Survey: Observing Galaxy Mass Assembly at z > 1

2005 ◽  
Vol 216 ◽  
pp. 390-397
Author(s):  
Karl Glazebrook ◽  
Keyword(s):  
Spectroscopic Studies ◽  
Star Forming ◽  
Hubble Sequence ◽  
First Results ◽  
Deep Survey ◽  
Redshift Survey ◽  
Mass Assembly ◽  
Galaxy Assembly ◽  
First Time ◽  
The Universe

The aim of the Gemini Deep Deep Survey is to push spectroscopic studies of complete galaxy samples (both red and blue objects) significantly beyond z = 1; this is the redshift where the current Hubble sequence of ellipticals and spirals is already extant. In the Universe at z = 2 the only currently spectroscopically confirmed galaxies are blue, star-forming and of fragmented morphology. Exploring this transition means filling the ‘redshift desert’ 1 < z < 2 where there is a dearth of spectroscopic measurements. To do this we need to secure redshifts of the oldest, reddest galaxies (candidate ellipticals) beyond z > 1 which has led us to carry out the longest exposure redshift survey ever done: 100 ksec spectroscopic MOS exposures with GMOS on Gemini North. We have developed an implementation of the CCD “nod & shuffle” technique to ensure precise sky-subtraction in these ultra-deep exposures. At the halfway mark the GDDS now has ∼ 36 galaxies in the redshift desert 1.2 < z < 2 extending up to z = 1.97 and I < 24.5 with secure redshifts based on weak rest-frame UV absorption features complete for both red, old objects and young, blue objects. The peak epoch of galaxy assembly is now being probed by direct spectroscopic investigation for the first time. on behalf of the GDDS team I present our first results on the properties of galaxies in the ‘redshift desert’.

Sardinia Radio Telescope (SRT) observations of Local Group dwarf galaxies

2017 ◽  
Vol 13 (S336) ◽  
pp. 109-112
Author(s):  
A. Tarchi ◽  
P. Castangia ◽  
G. Surcis ◽  
A. Brunthaler ◽  
K. M. Menten ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Radio Continuum ◽  
Maser Emission ◽  
Star Forming ◽  
Star Forming Regions ◽  
First Results ◽  
Ngc 6822 ◽  
Almost All

AbstractThe dwarf galaxies in the Local Group (LG) reveal a surprising amount of spatial structuring. In particular, almost all non-satellite dwarfs belong to one of two planes that show a very pronounced symmetry. In order to determine if these structures in the LG are dynamically stable or, alternatively, if they only represent transient alignments, proper motion measurements of these galaxies are required. A viable method to derive proper motions is offered by VLBI studies of 22-GHz water (and 6.7-GHz methanol) maser lines in star-forming regions.In 2016, in the framework of the Early Science Program of the Sardinia Radio Telescope (SRT), we have conducted an extensive observational campaign to map the entire optical body of all the LG dwarf galaxies that belong to the two planes, at C and K band, in a search for methanol and water maser emission.Here, we outline the project and present its first results on 3 targets, NGC 6822, IC 1613, and WLM. While no luminous maser emission has been detected in these galaxies, a number of interesting weaker detections has been obtained, associated with particularly active star forming regions. In addition, we have produced deep radio continuum maps for these galaxies, aimed at investigating their star forming activity and providing an improved assessment of star formation rates in these galaxies.

scholarly journals A closer look at the deep radio sky: Multi-component radio sources at 3 GHz VLA-COSMOS

2019 ◽  
Vol 627 ◽  
pp. A142
Author(s):  
E. Vardoulaki ◽  
E. F. Jiménez Andrade ◽  
A. Karim ◽  
M. Novak ◽  
S. K. Leslie ◽  
...  
Keyword(s):  
Radio Emission ◽  
Radio Continuum ◽  
Continuum Emission ◽  
High Angular Resolution ◽  
Radio Sources ◽  
Source Population ◽  
Data Set ◽  
Star Forming ◽  
Large Project ◽  
Automatic Code

Context. Given the unprecedented depth achieved in current large radio surveys, we are starting to probe populations of radio sources that have not been studied in the past. However, identifying and categorising these objects, differing in size, shape and physical properties, is becoming a more difficult task. Aims. In this data paper we present and characterise the multi-component radio sources identified in the VLA-COSMOS Large Project at 3 GHz (0.75 arcsec resolution, 2.3 μJy beam−1 rms), i.e. the radio sources which are composed of two or more radio blobs. Methods. The classification of objects into multi-components was done by visual inspection of 351 of the brightest and most extended blobs from a sample of 10,899 blobs identified by the automatic code BLOBCAT. For that purpose we used multi-wavelength information of the field, such as the 1.4 GHz VLA-COSMOS data and the Ultra Deep Survey with the VISTA telescope (UltraVISTA) stacked mosaic available for COSMOS. Results. We have identified 67 multi-component radio sources at 3 GHz: 58 sources with active galactic nucleus (AGN) powered radio emission and nine star-forming galaxies. We report eight new detections that were not observed by the VLA-COSMOS Large Project at 1.4 GHz, due to the slightly larger area coverage at 3 GHz. The increased spatial resolution of 0.75 arcsec has allowed us to resolve (and isolate) multiple emission peaks of 28 extended radio sources not identified in the 1.4 GHz VLA-COSMOS map. We report the multi-frequency flux densities (324 MHz, 325 MHz, 1.4 GHz & 3 GHz), star formation rates, and stellar masses of these objects. We find that multi-component objects at 3 GHz VLA-COSMOS inhabit mainly massive galaxies (> 1010.5 M⊙). The majority of the multi-component AGN lie below the main sequence of star-forming galaxies (SFGs), in the green valley and the quiescent region. Furthermore, we provide detailed descriptions of the objects and find that amongst the AGN there are two head-tail, ten core-lobe, nine wide-angle-tail (WAT), eight double-double or Z-/X-shaped, three bent-tail radio sources, and 26 symmetric sources, while amongst the SFGs we find the only star-forming ring seen in radio emission in COSMOS. Additionally, we report a large number (32 out of 58) of disturbed/bent multi-component AGN, 18 of which do not lie within X-ray groups in COSMOS (redshift range 0.08 ≤ z <  1.53). Conclusion. The high angular resolution and sensitivity of the 3 GHz VLA-COSMOS data set give us the opportunity to identify peculiar radio structures and sub-structures of multi-component objects, and relate them to physical phenomena such as AGN or star-forming galaxies. This study illustrates the complexity of the μJy radio-source population; at the sensitivity and resolution of 3 GHz VLA-COSMOS, the radio structures of AGN and SFG both emitting radio continuum emission, become comparable in the absence of clear, symmetrical jets. Thus, disentangling the AGN and SFG contributions using solely radio observations can be misleading in a number of cases. This has implications for future surveys, such as those done by square kilometre array (SKA) and precursors, which will identify hundreds of thousands of multi-component objects.

scholarly journals The DEEP2 Galaxy Redshift Survey: First Results on Galaxy Groups

2005 ◽  
Vol 625 (1) ◽  
pp. 6-22 ◽  
Author(s):  
Brian F. Gerke ◽  
Jeffrey A. Newman ◽  
Marc Davis ◽  
Christian Marinoni ◽  
Renbin Yan ◽  
...  
Keyword(s):  
Galaxy Groups ◽  
First Results ◽  
Redshift Survey ◽  
Galaxy Redshift ◽  
Deep2 Galaxy Redshift Survey

scholarly journals Spectral Characteristics of the 2dFGRS–NVSS Galaxies

2000 ◽  
Vol 17 (3) ◽  
pp. 234-240 ◽  
Author(s):  
C. A. Jackson ◽  
D. M. Londish
Keyword(s):  
Spectral Characteristics ◽  
Line Ratio ◽  
Emission Lines ◽  
Sky Survey ◽  
Show Evidence ◽  
Redshift Survey ◽  
Galaxy Redshift ◽  
Narrow Emission

AbstractWe have analysed the 2dF spectra of a sample of galaxies common to the 2dF Galaxy Redshift Survey (2dFGRS, Colless 1999) and the NRAO VLA Sky Survey (NVSS, Condon et al. 1998). Our sample comprises 88 galaxies selected by Sadler et al. (1999) from 30 2dFGRS fields observed in 1998. In this paper we discuss how this and future, much larger, samples of 2dFGRS–NVSS galaxies can be interpreted via analysis of those galaxies with strong narrow emission lines. Using diagnostic line ratio measurements, we confirm the majority of the eyeball classifications of Sadler et al. (1999), although many galaxies show evidence of being ‘composite’ galaxies—mixtures of AGN plus starburst components.

scholarly journals Faint 1.4-GHz radio sources in the 2dF Galaxy Redshift Survey

2004 ◽  
Vol 352 (4) ◽  
pp. 1245-1254 ◽  
Author(s):  
B. H. P. Chan ◽  
L. E. Cram ◽  
E. M. Sadler ◽  
N. E. B. Killeen ◽  
C. A. Jackson ◽  
...  
Keyword(s):  
Radio Sources ◽  
Redshift Survey ◽  
Galaxy Redshift

scholarly journals Studies of the Perseus Region.I.

2006 ◽  
Vol 2 (S237) ◽  
pp. 405-405
Author(s):  
Srabani Datta
Keyword(s):  
Young Stellar Objects ◽  
Stellar Objects ◽  
Star Forming ◽  
Bolometer Array ◽  
Sky Survey ◽  
Multiple Imaging ◽  
First Results ◽  
Multi Wavelength ◽  
Array Camera ◽  
Infrared Array

AbstractStudies of molecular clouds have shown that they evolve from turbulent gas and dust to form coherent, dense and connected structures. We have conducted a multi-wavelength study of one such molecular cloud, the Perseus star-forming region, which includes Barnard 1 (B1), Barnard 3(B3), Barnard 5 (B5), NGC 1333, IC 348, L1455 and L1448. The data obtained using the Infrared Array Camera (IRAC), Multiple Imaging Photometer (MIPS), the Sub-mm Common User Bolometer Array(SCUBA) and the 2 Micron All Sky Survey (2MASS)provides information about the geometric structure of the dust and gas covering large areas around young stellar objects (YSO), dust temperatures, effect of turbulence and processes of molecule formation and their relevance in the chemical and physical evolution of the cloud. This paper presents our first results.

Two Degree Field Galaxy Redshift Survey and Sloan Digital Sky Survey Galaxy Group Density Profiles

2005 ◽  
Vol 629 (1) ◽  
pp. 158-171 ◽  
Author(s):  
Eugenia Diaz ◽  
Ariel Zandivarez ◽  
Manuel E. Merchan ◽  
Hernan Muriel
Keyword(s):  
Sloan Digital Sky Survey ◽  
Density Profiles ◽  
Sky Survey ◽  
Redshift Survey ◽  
Galaxy Redshift ◽  
Group Density ◽  
Field Galaxy
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