Some estimates of the source counts at Planck Surveyor frequencies, using the 9C survey at 15 GHz

Waldram, Elizabeth; Bolton, Rosie; Pooley, G. G.; Riley, J. M.

doi:10.1111/j.1365-2966.2007.12025.x

Cited by 30 publications

(58 citation statements)

References 19 publications

(28 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular, a clear steepening (or a bending down) at mm wavelengths is theoretically expected (Kellermann 1966;Blandford & Königl 1979). This steepening has been already observed in some well known blazars (Clegg et al 1983) and has also been statistically suggested by recent analyses of different ERS samples at ν > 30 GHz (see, e.g., Waldram et al 2007;Gonzalez-Nuevo et al 2008).…”

Section: Introductionmentioning

confidence: 76%

See 1 more Smart Citation

High-frequency predictions for number counts and spectral properties of extragalactic radio sources. New evidence of a break at mm wavelengths in spectra of bright blazar sources

Tucci

Toffolatti

Zotti

et al. 2011

A&A

103

201

View full text Add to dashboard Cite

We present models to predict high-frequency counts of extragalactic radio sources using physically grounded recipes to describe the complex spectral behaviour of blazars that dominate the mm-wave counts at bright flux densities. We show that simple power-law spectra are ruled out by high-frequency (ν ≥ 100 GHz) data. These data also strongly constrain models featuring the spectral breaks predicted by classical physical models for the synchrotron emission produced in jets of blazars. A model dealing with blazars as a single population is, at best, only marginally consistent with data coming from current surveys at high radio frequencies. Our most successful model assumes different distributions of break frequencies, ν M , for BL Lacs and flat-spectrum radio quasars (FSRQs). The former objects have substantially higher values of ν M , implying that the synchrotron emission comes from more compact regions; therefore, a substantial increase of the BL Lac fraction at high radio frequencies and at bright flux densities is predicted. Remarkably, our best model is able to give a very good fit to all the observed data on number counts and on distributions of spectral indices of extragalactic radio sources at frequencies above 5 and up to 220 GHz. Predictions for the forthcoming sub-mm blazar counts from Planck, at the highest HFI frequencies, and from Herschel surveys are also presented.

show abstract

Section: Introductionmentioning

confidence: 76%

“…At frequencies ν > 20 GHz a further spectral steepening is still possible: a recent indication in this sense is coming from the follow-up of 9C sources (see Waldram et al 2007). …”

Section: High-frequency Steepening Of Steep-spectrum Sourcesmentioning

confidence: 99%

High-frequency predictions for number counts and spectral properties of extragalactic radio sources. New evidence of a break at mm wavelengths in spectra of bright blazar sources

Tucci

Toffolatti

Zotti

et al. 2011

A&A

103

201

View full text Add to dashboard Cite

show abstract

“…(a) [HB89] 0906+015, (b) PKS 0907+022. (Waldram et al 2007;Sadler et al 2008). Vieira et al (2009) find that their highest significance 150 GHz selected radio sources are consistent with flat spectral behavior (or α 0.1) between 5 GHz and 150 GHz but a possible steepening between 150 and 220 GHz.…”

Section: Introductionmentioning

confidence: 94%

Herschel-ATLAS: Blazars in the science demonstration phase field

González‐Nuevo¹,

Zotti

Andreani

et al. 2010

A&A

View full text Add to dashboard Cite

To investigate the poorly constrained sub-mm counts and spectral properties of blazars we searched for these in the Herschel-ATLAS (H-ATLAS) science demonstration phase (SDP) survey catalog. We cross-matched 500 μm sources brighter than 50 mJy with the FIRST radio catalogue. We found two blazars, both previously known. Our study is among the first blind blazar searches at sub-mm wavelengths, i.e., in the spectral regime where little is still known about the blazar SEDs, but where the synchrotron peak of the most luminous blazars is expected to occur. Our early results are consistent with educated extrapolations of lower frequency counts and question indications of substantial spectral curvature downwards and of spectral upturns at mm wavelengths. One of the two blazars is identified with a Fermi/LAT γ-ray source and a WMAP source. The physical parameters of the two blazars are briefly discussed. These observations demonstrate that the H-ATLAS survey will provide key information about the physics of blazars and their contribution to sub-mm counts.

show abstract

“…2): a sharp decrease of the slope at faint flux densities (S ν < ∼ 1 Jy at 30 GHz) signals the onset of incompleteness. Based on the ATCA 20 GHz counts Murphy et al 2010), we expect that the slope of the counts remains approximately constant over the limited flux density range covered by Kovac et al 2002) and at 33 GHz from the VSA data (grey box; Cleary et al 2005); the counts from the PACO (grey diamonds; Bonavera et al 2011) and the WMAP 5-yr surveys (grey squares; Massardi et al 2009), at the closest frequencies, and the counts estimated by Waldram et al (2007) (grey dashed line), exploiting multi-frequency follow-up observations of the 15 GHz 9C sources. The vertical dashed magenta line in the upper panel indicates the flux density completeness limit, 1.0 Jy, estimated for our primary sample Sect.…”

Section: Completeness and Uniformity Testsmentioning

confidence: 99%

Planckearly results. XIII. Statistical properties of extragalactic radio sources in thePlanckEarly Release Compact Source Catalogue

Ade¹,

Aghanim²,

Argüeso³

et al. 2011

A&A

105

View full text Add to dashboard Cite

The data reported in Planck's Early Release Compact Source Catalogue (ERCSC) are exploited to measure the number counts (dN/dS ) of extragalactic radio sources at 30, 44, 70, 100, 143 and 217 GHz. Due to the full-sky nature of the catalogue, this measurement extends to the rarest and brightest sources in the sky. At lower frequencies (30, 44, and 70 GHz) our counts are in very good agreement with estimates based on WMAP data, being somewhat deeper at 30 and 70 GHz, and somewhat shallower at 44 GHz. Planck's source counts at 143 and 217 GHz join smoothly with the fainter ones provided by the SPT and ACT surveys over small fractions of the sky. An analysis of source spectra, exploiting Planck's uniquely broad spectral coverage, finds clear evidence of a steepening of the mean spectral index above about 70 GHz. This implies that, at these frequencies, the contamination of the CMB power spectrum by radio sources below the detection limit is significantly lower than previously estimated.

show abstract

Some estimates of the source counts at Planck Surveyor frequencies, using the 9C survey at 15 GHz

Cited by 30 publications

References 19 publications

High-frequency predictions for number counts and spectral properties of extragalactic radio sources. New evidence of a break at mm wavelengths in spectra of bright blazar sources

High-frequency predictions for number counts and spectral properties of extragalactic radio sources. New evidence of a break at mm wavelengths in spectra of bright blazar sources

Herschel-ATLAS: Blazars in the science demonstration phase field

Planckearly results. XIII. Statistical properties of extragalactic radio sources in thePlanckEarly Release Compact Source Catalogue

Contact Info

Product

Resources

About