56011481
The Australia Telescope 20 GHz (AT20G) Survey: analysis of the extragalactic source sample
The Australia Telescope 20 GHz (AT20G) survey is a blind survey of the whole Southern sky at 20 GHz with follow-up observations at 4.8, 8.6 and 20 GHz carried out with the Australia Telescope Compact Array (ATCA) from 2004 to 2008. In this paper we present an analysis of radio spectral properties in total intensity and polarization, sizes, optical identifications and redshifts of the sample of the 5808 extragalactic sources in the survey catalogue of confirmed sources over 6.1 sr in the Southern sky (i.e. the whole Southern sky excluding the strip at Galactic latitude |b| < ). 
 
 
 
The sample has a flux density limit of 40 mJy. Completeness has been measured as a function of scan region and flux density. Averaging over the whole survey area the follow-up survey is 78 per cent complete above 50 mJy and 93 per cent complete above 100 mJy. 3332 sources with declination δ − 0.5 (S∝να). The fraction of flat-spectrum sources decreases from 81 per cent for S20 GHz > 500 mJy to 60 per cent for S20 GHz < 100 mJy. There is also a clear spectral steepening at higher frequencies with the median α decreasing from −0.16 between 4.8 and 8.6 GHz to −0.28 between 8.6 and 20 GHz. 
 
 
 
Simultaneous observations in polarization are available for all the sources at all the frequencies. 768 sources have a good-quality detection of polarized flux density at 20 GHz; 467 of them were also detected in polarization at 4.8 and/or at 8.6 GHz so that it has been possible to compare the spectral behaviour in total intensity and polarization. We have found that the polarized fraction increases slightly with frequency and decreases with flux density. The spectral indices in total intensity and in polarization are, on average, close to each other, but we also found several sources for which the spectral shape of the polarized emission is substantially different from the spectral shape in total intensity. The correlation between the spectral indices in total intensity and in polarization is weaker for flat-spectrum sources. 
 
 
 
Cross-matches and comparisons have been made with other catalogues at lower radio frequencies, and in the optical, X-ray and γ-ray bands. Redshift estimates are available for 825 sources.
16781872
Cosmic evolution and unified models for radio AGN
A new method of deriving the cosmological evolution of radio AGN is described which is based on the premise of unified models for quasars and radio galaxies.
14097040
Extragalactic radio source evolution&unification: clues to the demographics of blazars
In this paper we discuss the demographics of the radio blazar population: (i) what are their parent ('unbeamed') sources and (ii) what magnitude and/or type of evolution have they undergone ? The discussion is based on models of radio source evolution and beaming based on a 'dual population' unification paradigm. These models, developed from radio blazar properties in bright samples, predict blazar demographic trends at the lower flux-density levels; samples from deep mJy-level surveys (e.g. NVSS and FIRST) may now provide direct tests of these predictions. All galaxies are radio galaxies in a sense. The scale of activity ranges from 'normal' galaxies (like our own) whose radio emission emanates from supernova remnants. At higher radio powers are the 'starburst' galaxies, greatly-enhanced stellar activity resulting in stronger radio emission. At similar radio powers are the Seyfert galaxies with their small-scale radio core-jet structures and with clear indication of AGN activity. At the top end of the scale are the powerful radio galaxies, together with BL Lacs and quasars, the latter two being collectively termed blazars. Radio galaxies tend to have steep radio spectra and therefore dominate low radio-frequency (ν < 0.5 GHz) surveys. The structures are predominantly double-lobed; Fanaroff & Riley (1974) compared the distances between central maxima of the radio structures to overall size and discovered a dichotomy. Sources with regions of maximum brightness separated by more than 0.5 times the overall source size are edge-brightened (FRII), while when the regions of maximum brightness lies within this limit the source has diffuse outer lobes (FRI) (centrally concentrated); and the highest radio power objects are predominantly FRIIs whilst those of lower radio power are usually FRIs. The overlap between the classes at middling radio powers is seen in the local radio luminos-ity function (Figure 1), and the division is known to be a function of optical luminosity as well as radio (Owen and Ledlow 1993).
15444325
The Redshift Cutoff and the Quasar Epoch
We have obtained complete redshift information for a sample of 442 radio-loud quasars with flux densities S11 ≥ 0.25 Jy. These come from a completely-identified sample of 878 flat-spectrum radio sources, so there is no optical magnitude limit. With these quasars, therefore, we can map out the entire quasar epoch, unhindered by optical selection effects and any intervening dust. The rapid decline in true space density above z ∼ 2.5 is confirmed. It agrees closely with that obtained from optically-selected samples, indicating that these are also not significantly affected by dust. The evolution of the quasar space density is similar to that deduced for the global star formation rate, implying that the quasar epoch may also be that of star formation. This sample of radio-selected quasars can now be used in a variety of other studies, including unbiased searches for damped Lyabsorbers, studies of the phenomenon of "red quasars", and searches for high-redshift molecular absorption systems.
117637282
The Redshift Distribution of Extragalactic Radio Sources
Extragalactic radio sources are a unique cosmological probe in that they trace large-scale structure on scales inaccessible to other wavelengths. However as radio survey data is inherently 2D, the redshift distribution, N(z), is necessary to derive spatial information. To obtain this distribution either we measure thousands of radio source redshifts to directly determine N(z) or we derive N(z) from statistical analyses of radio source count and identification data. 
In this paper we show how the dual-population unification scheme can be incorporated into a rigorous statistical analysis of radio source count data, with the result that our simple parametric evolution and beaming model revises previous estimations of N(z), specifically at low flux densites. This revision is particularly pertinent given that the new generation of radio surveys extend to milli-jansky flux density levels: sampling source densities high enough to reveal spatial structure. In turn, these new radio surveys will provide potent tests which will refine our model.
118994394
Radio Galaxy Spectra
Radio spectra of radio galaxies are often ascribed a simple power law form ($S_{\nu} \propto \nu^{\alpha}$) with the spectral index, $\alpha$, being of order -0.7. However, all radio galaxies deviate from this simple power law behaviour. In this paper we derive simple expressions for the average rest-frame spectra of FRI and FRII radio galaxies. These will be used to describe the spectral curvature of the parent (FRI and FRII) populations in models of radio source evolution.
119997511
Probing the mechanism of neutrinoless double beta decay with SuperNEMO
Abstract The SuperNEMO experiment is being designed to search for neutrinoless double beta decay. Its experimental technique of tracking and calorimetry provides the means to discriminate different underlying mechanisms for neutrinoless double beta decay by measuring the angular and energy distributions of electrons. The results of a study by the SuperNEMO Collaboration and F. Deppisch (in preparation)  [7] for identifying light Majorana neutrino exchange and right-handed currents are presented.
119249502
Gamma rays from top-mediated dark matter annihilations
Lines in the energy spectrum of gamma rays are a fascinating experimental signal, which are often considered ''smoking gun" evidence of dark matter annihilation. The current generation of gamma ray observatories are currently closing in on parameter space of great interest in the context of dark matter which is a thermal relic. We consider theories in which the dark matter's primary connection to the Standard Model is via the top quark, realizing strong gamma ray lines consistent with a thermal relic through the forbidden channel mechanism proposed in the Higgs in Space Model. We consider realistic UV-completions of the Higgs in Space and related theories, and show that a rich structure of observable gamma ray lines is consistent with a thermal relic as well as constraints from dark matter searches and the LHC. Particular attention is paid to the one loop contributions to the continuum gamma rays, which can easily swamp the line signals in some cases, and have been largely overlooked in previous literature.
73704343
WIMP-induced gamma ray spectrum of active Galactic nuclei
As direct and indirect dark matter detection experiments continue to place stringent constraints on WIMP masses and couplings, it becomes imperative to expand the scope of the search for particle dark matter by looking in new and exotic places. One such place may be the core of active galactic nuclei where the density of dark matter is expected to be extremely high. Recently, several groups have explored the possibility of observing signals of dark matter from its interactions with the high-energy jets emanating from these galaxies. In this work, we build upon these analyses by including the other components of the WIMP-induced gamma ray spectrum of active galactic nuclei; namely, (1) the continuum from WIMP annihilation into light standard model states which subsequently radiate and/or decay into photons and (2) the direct (loop-induced) decay into photons. We work in the context of models of universal extra dimensions (in particular, a model with two extra dimensions) and compute all three components of the gamma ray spectrum and compare with current data. We find that the model with two extra dimensions exhibits several interesting features which may be observable with the Fermi gamma ray telescope. We also show that, in conjunction with other measurements, the gamma ray spectrum from AGN can be an invaluable tool for restricting WIMP parameter space.
18512510
Higgs boson production with one bottom quark including higher-order soft-gluon corrections
A Higgs boson produced in association with one or more bottom quarks is of great theoretical and experimental interest to the high-energy community. A precise prediction of its total and differential cross section can have a great impact on the discovery of a Higgs boson with large bottom-quark Yukawa coupling, like the scalar (h{sup 0} and H{sup 0}) and pseudoscalar (A{sup 0}) Higgs bosons of the minimal supersymmetric standard model in the region of large tan{beta}. In this paper we apply the threshold resummation formalism to determine both differential and total cross sections for bg{yields}b{phi} (where {phi}=h{sup 0},H{sup 0}), including up to next-to-next-to-next-to-leading order soft plus virtual QCD corrections at next-to-leading logarithmic accuracy. We present results for both the Fermilab Tevatron and the CERN Large Hadron Collider.
119298520
The WIMP Forest: Indirect Detection of a Chiral Square
We consider the signals of indirect dark matter detection resulting from a theory of two universal extra dimensions compactified on a chiral square. Aside from the continuum emission, which is a generic prediction of most dark matter candidates, we find a series of prominent annihilation lines (a WIMP forest) that, after convolution with the angular resolution of current experiments, leads to a distinctive (2-bump plus continuum) spectrum, which may be visible in the near future with the Fermi Gamma-Ray Space Telescope (formerly known as GLAST).