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Megahertz peaked-spectrum sources in the Boötes field I - a route towards finding high-redshift AGN?

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Megahertz peaked-spectrum sources in the Boötes field I - a route towards finding high-redshift AGN? / Coppejans, Rocco; Cseh, David; Williams, Wendy L.; Velzen, Sjoert van; Falcke, Heino.

In: Monthly Notices of the Royal Astronomical Society, Vol. 450, No. 2, 21.06.2015, p. 1477-1485.

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Coppejans, Rocco ; Cseh, David ; Williams, Wendy L. ; Velzen, Sjoert van ; Falcke, Heino. / Megahertz peaked-spectrum sources in the Boötes field I - a route towards finding high-redshift AGN?. In: Monthly Notices of the Royal Astronomical Society. 2015 ; Vol. 450, No. 2. pp. 1477-1485.

Bibtex

@article{0644361d059c4872bb4a1d3f9fac9059,
title = "Megahertz peaked-spectrum sources in the Bo{\"o}tes field I - a route towards finding high-redshift AGN?",
abstract = "We present a 324.5MHz image of the NOAO Bo\{"}otes field that was made using Very Large Array (VLA) P-band observations. The image has a resolution of 5.6x5.1arcsec, a radius of $2.05^\circ$ and a central noise of ~0.2mJy\beam. Both the resolution and noise of the image are an order of magnitude better than what was previously available at this frequency and will serve as a valuable addition to the already extensive multiwavelength data that are available for this field. The final source catalogue contains 1370 sources and has a median 325 to 1400MHz spectral index of -0.72. Using a radio colour-colour diagram of the unresolved sources in our catalogue, we identify 33 megahertz peaked-spectrum (MPS) sources. Based on the turnover frequency linear size relation for the gigahertz peaked-spectrum (GPS) and compact steep-spectrum (CSS) sources, we expect that the MPS sources that are compact on scales of tens of milliarcseconds should be young radio loud active galactic nuclei at high (z>2) redshifts. Of the 33 MPS sources, we were able to determine redshifts for 24, with an average redshift of 1.3. Given that five of the sources are at z>2, that the four faint sources for which we could not find redshifts are likely at even higher redshifts and that we could only select sources that are compact on a scale of ~5arcsec, there is encouraging evidence that the MPS method can be used to search for high-redshift sources.",
keywords = "astro-ph.GA, astro-ph.CO",
author = "Rocco Coppejans and David Cseh and Williams, {Wendy L.} and Velzen, {Sjoert van} and Heino Falcke",
note = "This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. {\textcopyright} 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.",
year = "2015",
month = jun,
day = "21",
doi = "10.1093/mnras/stv681",
language = "English",
volume = "450",
pages = "1477--1485",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "2",

}

RIS

TY - JOUR

T1 - Megahertz peaked-spectrum sources in the Boötes field I - a route towards finding high-redshift AGN?

AU - Coppejans, Rocco

AU - Cseh, David

AU - Williams, Wendy L.

AU - Velzen, Sjoert van

AU - Falcke, Heino

N1 - This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.

PY - 2015/6/21

Y1 - 2015/6/21

N2 - We present a 324.5MHz image of the NOAO Bo\"otes field that was made using Very Large Array (VLA) P-band observations. The image has a resolution of 5.6x5.1arcsec, a radius of $2.05^\circ$ and a central noise of ~0.2mJy\beam. Both the resolution and noise of the image are an order of magnitude better than what was previously available at this frequency and will serve as a valuable addition to the already extensive multiwavelength data that are available for this field. The final source catalogue contains 1370 sources and has a median 325 to 1400MHz spectral index of -0.72. Using a radio colour-colour diagram of the unresolved sources in our catalogue, we identify 33 megahertz peaked-spectrum (MPS) sources. Based on the turnover frequency linear size relation for the gigahertz peaked-spectrum (GPS) and compact steep-spectrum (CSS) sources, we expect that the MPS sources that are compact on scales of tens of milliarcseconds should be young radio loud active galactic nuclei at high (z>2) redshifts. Of the 33 MPS sources, we were able to determine redshifts for 24, with an average redshift of 1.3. Given that five of the sources are at z>2, that the four faint sources for which we could not find redshifts are likely at even higher redshifts and that we could only select sources that are compact on a scale of ~5arcsec, there is encouraging evidence that the MPS method can be used to search for high-redshift sources.

AB - We present a 324.5MHz image of the NOAO Bo\"otes field that was made using Very Large Array (VLA) P-band observations. The image has a resolution of 5.6x5.1arcsec, a radius of $2.05^\circ$ and a central noise of ~0.2mJy\beam. Both the resolution and noise of the image are an order of magnitude better than what was previously available at this frequency and will serve as a valuable addition to the already extensive multiwavelength data that are available for this field. The final source catalogue contains 1370 sources and has a median 325 to 1400MHz spectral index of -0.72. Using a radio colour-colour diagram of the unresolved sources in our catalogue, we identify 33 megahertz peaked-spectrum (MPS) sources. Based on the turnover frequency linear size relation for the gigahertz peaked-spectrum (GPS) and compact steep-spectrum (CSS) sources, we expect that the MPS sources that are compact on scales of tens of milliarcseconds should be young radio loud active galactic nuclei at high (z>2) redshifts. Of the 33 MPS sources, we were able to determine redshifts for 24, with an average redshift of 1.3. Given that five of the sources are at z>2, that the four faint sources for which we could not find redshifts are likely at even higher redshifts and that we could only select sources that are compact on a scale of ~5arcsec, there is encouraging evidence that the MPS method can be used to search for high-redshift sources.

KW - astro-ph.GA

KW - astro-ph.CO

U2 - 10.1093/mnras/stv681

DO - 10.1093/mnras/stv681

M3 - Article

VL - 450

SP - 1477

EP - 1485

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 2

ER -