Constraining the evolution of young radio-loud AGN

GPS and CSS radio sources are the objects of choice to investigate the evolution of young radio-loud AGN. Previous investigations, mainly based on number counts and source size distributions, indicate that GPS/CSS sources decrease significantly in radio power when evolving into old, extended objects. We suggest this is preceded by a period of increase in radio luminosity, which lasts as long as the radio source is confined within the core-radius of its host galaxy. We have selected a sample of nearby compact radio sources, unbiased by radio spectrum, to determine their radio luminosity function, size distribution, dynamical ages, and emission line properties in a complete and homogeneous way. First results indicate that the large majority of objects (>80%) exhibit classical GPS/CSS radio spectra, and show structures consistent with the being compact double, or compact symmetric objects. This sample provides and ideal basis to further test and constrain possible evolution scenarios, and to investigate the relation between radio spectra and morphologies, orientation and Doppler boosting in samples of young radio-loud AGN, in an unbiased way.Comment: LaTeX, 8 pages, 3 figs: Accepted by Publications of the Astronomical Society of Australia, as part of the proceedings of the 3rd GPS/CSS workshop, eds. T. Tzioumis et a

Unique and interactive associations of callous-unemotional traits, impulsivity and narcissism with child and adolescent Conduct Disorder symptoms

The construct of psychopathy remains underrepresented in the clinical diagnosis of Conduct Disorder (CD) as the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5) only addresses one out of the three dimensions of child psychopathy, Callous Unemotional (CU) traits. This study tests if and to what extent there are unique and interactive associations of CU traits, impulsivity, and grandiosity with child and adolescent CD symptoms. Data were collected from two separate community samples of children (N = 1599; Mage = 9.46, SD = 1.65; 52% female) and adolescents (N = 2719; Mage = 16.99, SD = 0.99; 49% female), who were followed longitudinally after a year. Hierarchical linear regression analyses were conducted, testing cross-sectional and longitudinal associations with CD symptoms, taking into account all three psychopathy dimensions. The cross-sectional findings indicate that only youth presenting a combination of all three psychopathy dimensions scored above the clinical cut-off score for CD. On the other hand, longitudinal findings provided evidence that the combination of high initial levels of CD and CU traits as well as the combination between CD, grandiosity, and impulsivity can lead to clinical levels of future CD symptoms. Findings also indicated that CU traits and impulsivity more strongly predicted adolescent than child CD symptoms, and that CU traits were more strongly associated with boys' than girls' CD symptoms. Findings support the inclusion of CU traits as a specifier for the diagnosis of CD, and provide evidence that other psychopathy dimensions can also help clinicians to better understand and treat youth with CD, and should be considered for future revisions of the DSM

A Very Radio-Loud Narrow-Line Seyfert 1: PKS 2004-447

We have discovered a very radio-loud Narrow-Line Seyfert 1 candidate: PKS 2004-447. This Seyfert is consistent with the formal definition for NLS1s, although it does not have quite the same spectral features as some typical members of this subclass. Only ROSAT survey data is available at X-ray wavelengths, so it has not been possible to compare this source with other NLS1s at these wavelengths. A full comparison of this source with other members of the subclass will improve our physical understanding of NLS1s. In addition, using standard calculations, we estimate the central black hole to have a mass of $\sim 5 \times 10^6 M_{\odot}$. This does not agree with predictions in the literature, that radio-loud AGN host very massive black holes.Comment: 15 pages, 4 figures, accepted for publication in ApJ, minor typos change

The host galaxies of three radio-loud quasars: 3C 48, 3C 345, and B2 1425+267

Observations with the Wide-Field/Planetary Camera-2 of the Hubble Space Telescope (HST) are presented for three radio-loud quasars: 3C 48 (z=0.367), B2 1425+267 (z=0.366), and 3C 345 (z=0.594). All three quasars have luminous (~4 L^*) galaxies as hosts, which are either elliptical (B2 1425+267 and 3C 345) or interacting (3C 48), and all hosts are 0.5 - 1.0 mag bluer in (V-I) than other galaxies with the same overall morphology at similar redshifts to the quasars. The host of 3C 48 has many H II regions and a very extended tidal tail. All nine of the radio-loud quasars studied here and in Bahcall et al. (1997) either have bright elliptical hosts or occur in interacting systems. There is a robust correlation between the radio emission of the quasar and the luminosity of host galaxy; the radio-loud quasars reside in galaxies that are on average about 1 mag brighter than hosts of the radio-quiet quasars.Comment: Accepted for publication in ApJ. 3 postscript and 3 jpeg figures. Original figures may be found in ftp://eku.sns.ias.edu/pub/sofia/RadioLoud

X-ray-emitting Atmospheres of B2 Radio Galaxies

We report ROSAT PSPC spatial and spectral analysis of the eight B2 radio galaxies NGC 315, NGC 326, 4C 35.03, B2 0326+39, NGC 2484, B2 1040+31, B2 1855+37, and 3C 449, expected to be representative of the class of low-power radio galaxies. Multiple X-ray components are present in each, and the gas components have a wide range of linear sizes and follow an extrapolation of the cluster X-ray luminosity/temperature correlation, implying that there is no relationship between the presence of a radio galaxy and the gas fraction of the environment. No large-scale cooling flows are found. There is no correlation of radio-galaxy size with the scale or density of the X-ray atmosphere. This suggests that it is processes on scales less than those of the overall gaseous environments which are the major influence on radio-source dynamics. The intergalactic medium is usually sufficient to confine the outer parts of the radio structures, in some cases even to within 5 kpc of the core. In the case of NGC 315, an extrapolation suggests that the pressure of the atmosphere may match the minimum pressure in the radio source over a factor of about 40 in linear size (a factor of about 1600 in pressure).Comment: 34 pages, including 10 figures, using aasms4.sty To appear in the Ap

Direct CP, T and/or CPT violations in the K^0-\bar{K^0} system - Implications of the recent KTeV results on 2π2\pi decays -

The recent results on the CP violating parameters Re(e'/e) and \Delta\phi = \phi_{00}-\phi_{+-} reported by the KTeV Collaboration are analyzed with a view to constrain CP, T and CPT violations in a decay process. Combining with some relevant data compiled by the Particle Data Group, we find Re(e_2-e_0) = (0.85 +- 3.11)*10^{-4} and Im(e_2-e_0) = (3.2 +- 0.7)*10^{-4}, where Re(e_I) and Im(e_I) represent respectively CP/CPT and CP/T violations in decay of K^0 and \bar{K^0} into a 2\pi state with isospin I.Comment: 7 pages, No figure

Optical spectroscopy of faint gigahertz peaked spectrum sources

We present spectroscopic observations of a sample of faint Gigahertz Peaked Spectrum (GPS) radio sources drawn from the Westerbork Northern Sky Survey (WENSS). Redshifts have been determined for 19 (40%) of the objects. The optical spectra of the GPS sources identified with low redshift galaxies show deep stellar absorption features. This confirms previous suggestions that their optical light is not significantly contaminated by AGN-related emission, but is dominated by a population of old (>9 Gyr) and metal-rich (>0.2 [Fe/H]) stars, justifying the use of these (probably) young radio sources as probes of galaxy evolution. The optical spectra of GPS sources identified with quasars are indistinguishable from those of flat spectrum quasars, and clearly different from the spectra of Compact Steep Spectrum (CSS) quasars. The redshift distribution of the GPS quasars in our radio-faint sample is comparable to that of the bright samples presented in the literature, peaking at z ~ 2-3. It is unlikely that a significant population of low redshift GPS quasars is missed due to selection effects in our sample. We therefore claim that there is a genuine difference between the redshift distributions of GPS galaxies and quasars, which, because it is present in both the radio-faint and bright samples, can not be due to a redshift-luminosity degeneracy. It is therefore unlikely that the GPS quasars and galaxies are unified by orientation, unless the quasar opening angle is a strong function of redshift. We suggest that the GPS quasars and galaxies are unrelated populations and just happen to have identical observed radio-spectral properties, and hypothesise that GPS quasars are a sub-class of flat spectrum quasars.Comment: LaTeX, 13 pages. Accepted by MNRAS. For related papers see http://www.ast.cam.ac.uk/~snelle

Radio-Excess IRAS Galaxies: PMN/FSC Sample Selection

A sample of 178 extragalactic objects is defined by correlating the 60 micron IRAS FSC with the 5 GHz PMN catalog. Of these, 98 objects lie above the radio/far-infrared relation for radio-quiet objects. These radio-excess galaxies and quasars have a uniform distribution of radio excesses and appear to be a new population of active galaxies not present in previous radio/far-infrared samples. The radio-excess objects extend over the full range of far-infrared luminosities seen in extragalactic objects. Objects with small radio excesses are more likely to have far-infrared colors similar to starbursts, while objects with large radio excesses have far-infrared colors typical of pure AGN. Some of the most far-infrared luminous radio-excess objects have the highest far-infrared optical depths. These are good candidates to search for hidden broad line regions in polarized light or via near-infrared spectroscopy. Some low far-infrared luminosity radio-excess objects appear to derive a dominant fraction of their far-infrared emission from star formation, despite the dominance of the AGN at radio wavelengths. Many of the radio-excess objects have sizes likely to be smaller than the optical host, but show optically thin radio emission. We draw parallels between these objects and high radio luminosity Compact Steep-Spectrum (CSS) and GigaHertz Peaked-Spectrum (GPS) objects. Radio sources with these characteristics may be young AGN in which the radio activity has begun only recently. Alternatively, high central densities in the host galaxies may be confining the radio sources to compact sizes. We discuss future observations required to distinguish between these possibilities and determine the nature of radio-excess objects.Comment: Submitted to AJ. 44 pages, 11 figures. A version of the paper with higher quality figures is available from http://www.mso.anu.edu.au/~cdrake/PMNFSC/paperI

Near-IR spectroscopy of PKS1549-79: a proto-quasar revealed?

We present a near-IR spectrum of the nearby radio galaxy PKS1549-79 (z=0153). These data were taken with the aim of testing the idea that this object contains a quasar nucleus that is moderately extinguished, despite evidence that its radio jet points close to our line-of-sight. We detect broad Paschen Alpha emission (FWHM ~1745 km/s), relatively bright continuum emission, and a continuum slope consistent with a reddened quasar spectrum (3.1 < Av < 7.3), all emitted by an unresolved point source. Therefore we conclude that we have, indeed, detected a hidden quasar nucleus in PKS1549-79. Combined with previous results, these observations are consistent with the idea that PKS1549-79 is a young radio source in which the cocoon of debric left over from the triggering events has not yet been swept aside by circumnuclear outflows.Comment: 6 pages, 4 figures, accepted for publication in MNRA

Stability subtypes of callous–unemotional traits and conduct disorder symptoms and their correlates

Callous unemotional traits and conduct disorder symptoms tend to co-occur across development, with existing evidence pointing to individual differences in the co-development of these problems. The current study identified groups of at risk adolescents showing stable (i.e., high on both conduct disorder and callous-unemotional symptoms, high only on either callous-unemotional or conduct disorder symptoms) or increasing conduct disorder and callous-unemotional symptoms. Data were collected from a sample of 2038 community adolescents between 15 and 18 years (1070 females, Mage = 16) of age. A longitudinal design was followed in that adolescent reports were collected at two time points, one year apart. Increases in conduct disorder symptoms and callous-unemotional traits were accompanied by increases in anxiety, depressive symptoms, narcissism, proactive and reactive aggression and decreases in self-esteem. Furthermore, adolescents with high and stable conduct disorder symptoms and callous-unemotional traits were consistently at high risk for individual, behavioral and contextual problems. In contrast, youth high on callous-unemotional traits without conduct disorder symptoms remained at low-risk for anxiety, depressive symptoms, narcissism, and aggression, pointing to a potential protective function of pure callous-unemotional traits against the development of psychopathological problems