The Origin of Double-Peaked Narrow Lines in Active Galactic Nuclei III: Feedback from Biconical AGN Outflows

We apply an analytic Markov Chain Monte Carlo model to a sample of 18 AGN-driven biconical outflows that we identified from a sample of active galaxies with double-peaked narrow emission lines at z < 0.1 in the Sloan Digital Sky Survey. We find that 8/18 are best described as asymmetric bicones, 8/18 are nested bicones, and 2/18 are symmetric bicones. From the geometry and kinematics of the models, we find that these moderate-luminosity AGN outflows are large and energetic. The biconical outflows axes are randomly oriented with respect to the photometric major axis of the galaxy, implying a randomly oriented and clumpier torus to collimate the outflow, but the torus also allows some radiation to escape equatorially. We find that 16/18 (89%) outflows are energetic enough to drive a two-staged feedback process in their host galaxies. All of these outflows geometrically intersect the photometric major axis of the galaxy, and 23% of outflow host galaxies are significantly redder or have significantly lower specific star formation rates when compared to a matched sample of active galaxies.Comment: 32 pages, 11 figures, accepted for publication in MNRAS; See Figure 7 for a summary of the finding

Minding the Tragic Gap: Conversations of Invisibility in Early Childhood Music Education

During the last few decades, the music education profession has slowly begun to recognize the impact of music experiences in early childhood. Key publications in the 1970s drew attention to music education for young children (Greenberg 1976, Simons 1978, Zimmerman 1972). Articles focusing on young children\u27s musical development appeared in the 1980s (Hargreaves, 1986; Peery, Peery, & Draper, 1987; Sloboda, 1985; Swanick & Tillman, 1986). MENC (now the NationalAssociation for Music Education-NafME) began to address early childhood music education through focus days attached to biennial national conferences and through the establishment of the Early Childhood Special Research Interest Group. Yet in general, the music education profession lags behind other disciplines in recognizing the needs of young children. In this gap of recognition, young children remain an underrepresented population in the music. How do we change the perception of young children\u27s musical capabilities and abilities with parents, pre-service teachers, and colleagues

The Origin of Double-peaked Narrow Lines in Active Galactic Nuclei. IV. Association with Galaxy Mergers

Double-peaked narrow emission lines in active galactic nucleus (AGN) spectra can be produced by AGN outflows, rotation, or dual AGNs, which are AGN pairs in ongoing galaxy mergers. Consequently, double-peaked narrow AGN emission lines are useful tracers of the coevolution of galaxies and their supermassive black holes, as driven by AGN feedback and AGN fueling. We investigate this concept further with follow-up optical longslit observations of a sample of 95 Sloan Digital Sky Survey (SDSS) galaxies that have double-peaked narrow AGN emission lines. Based on a kinematic analysis of the longslit spectra, we confirm previous work that finds that the majority of double-peaked narrow AGN emission lines are associated with outflows. We also find that eight of the galaxies have companion galaxies with line-of-sight velocity separations < 500 km/s and physical separations <30 kpc. Since we find evidence of AGNs in both galaxies, all eight of these systems are compelling dual AGN candidates. Galaxies with double-peaked narrow AGN emission lines occur in such galaxy mergers at least twice as often as typical active galaxies. Finally, we conclude that at least 3% of SDSS galaxies with double-peaked narrow AGN emission lines are found in galaxy mergers where both galaxies are resolved in SDSS imaging.Comment: 14 pages, 2 figures, ApJ in pres

Kiloparsec-scale Spatial Offsets in Double-peaked Narrow-line Active Galactic Nuclei. I. Markers for Selection of Compelling Dual Active Galactic Nucleus Candidates

Merger-remnant galaxies with kpc-scale separation dual active galactic nuclei (AGNs) should be widespread as a consequence of galaxy mergers and triggered gas accretion onto supermassive black holes, yet very few dual AGNs have been observed. Galaxies with double-peaked narrow AGN emission lines in the Sloan Digital Sky Survey are plausible dual AGN candidates, but their double-peaked profiles could also be the result of gas kinematics or AGN-driven outflows and jets on small or large scales. To help distinguish between these scenarios, we have obtained spatial profiles of the AGN emission via follow-up long-slit spectroscopy of 81 double-peaked narrow-line AGNs in SDSS at 0.03 < z < 0.36 using Lick, Palomar, and MMT Observatories. We find that all 81 systems exhibit double AGN emission components with ~kpc projected spatial separations on the sky, which suggests that they are produced by kpc-scale dual AGNs or kpc-scale outflows, jets, or rotating gaseous disks. In addition, we find that the subsample (58%) of the objects with spatially compact emission components may be preferentially produced by dual AGNs, while the subsample (42%) with spatially extended emission components may be preferentially produced by AGN outflows. We also find that for 32% of the sample the two AGN emission components are preferentially aligned with the host galaxy major axis, as expected for dual AGNs orbiting in the host galaxy potential. Our results both narrow the list of possible physical mechanisms producing the double AGN components, and suggest several observational criteria for selecting the most promising dual AGN candidates from the full sample of double-peaked narrow-line AGNs. Using these criteria, we determine the 17 most compelling dual AGN candidates in our sample.Comment: 12 pages, 8 figures, published in ApJ. Modified from original version to reflect referee's comment

Diversified crop rotations and organic amendments as strategies for increasing soil carbon storage and stabilisation in UK arable systems

Adaptations in crop rotation with the inclusion of temporary grass-clover leys and organic amendments, have been promoted as effective ways to improve soil carbon (C) sequestration and mitigate climate change in agricultural systems. However, there are still a lot of uncertainties related to i) the combined effects of different crop rotations and different fertilisation sources, e.g., organic amendments, on soil C stocks; and ii) their potential effect on C stabilisation. The objective of this study was to evaluate the effect of different arable crop rotations with varying degrees of diversity in crop type and lengths of grass-clover ley periods and fertilisation sources on soil C stocks and C stabilisation down to 0.60 m soil depth. This was investigated in a long-term factorial field experiment-combining different crop rotation (cereal-intensive conventional vs. diversified legume-intensive organic) with different lengths of grass-clover ley periods (2 vs. 3 years), fertilisation sources (mineral vs. compost), and years (samples taken at the beginning and at the last year of one complete cycle of rotation; 8 years apart)-to explore their individual and interactive effect on soil C stock and C stabilisation at two soil depths (0–0.30 and 0.30–0.60 m). Soil C stabilisation was assessed using a unique combination of three different techniques: physical fractionation for separation of C associated to organic and mineral fractions, thermal analysis combined with differential scanning calorimetry and a quadrupole mass spectrometry (TG-DSC-QMS) for physical-chemical aspects, and pyrolysis coupled with gas chromatography-mass spectrometry (Py-GC/MS) for molecular structural information. The findings showed higher soil C stocks under the diversified organic rotation with 3 years of grass-clover ley period at both soil depths, regardless of the fertilisation source or sampling year. However, the organic rotation seemed to deliver stable soil C stocks only in the subsoil layer. Compost fertilisation, in turn, increased topsoil C stocks between the two sample dates under both rotations, and it appears to be stable. These results suggested that combining a diversified organic rotation with 3 years grass-clover ley with compost fertilisation could be one way for agricultural systems to deliver stable soil C sequestration

Systematic Blueshift of Line Profiles in the Type IIn Supernova 2010jl: Evidence for Post-Shock Dust Formation?

Type IIn SNe show spectral evidence for strong interaction between their blast wave and dense circumstellar material (CSM) around the progenitor star. SN2010jl was the brightest core-collapse SN in 2010, and it was a Type IIn explosion with strong CSM interaction. Andrews et al. recently reported evidence for an IR excess in SN2010jl, indicating either new dust formation or the heating of CSM dust in an IR echo. Here we report multi-epoch spectra of SN2010jl that reveal the tell-tale signature of new dust formation: emission-line profiles becoming systematically more blueshifted as the red side of the line is blocked by increasing extinction. The effect is seen clearly in the intermediate-width (400--4000 km/s) component of H$\alpha$ beginning roughly 30d after explosion. Moreover, we present near-IR spectra demonstrating that the asymmetry in the hydrogen-line profiles is wavelength dependent, appearing more pronounced at shorter wavelengths. This evidence suggests that new dust grains had formed quickly in the post-shock shell of SN 2010jl arising from CSM interaction. Since the observed dust temperature has been attributed to an IR echo and not to new dust, either (1) IR excess emission at $\lambda < 5 \mu$m is not a particularly sensitive tracer of new dust formation in SNe, or (2) some assumptions about expected dust temperatures might require further study. Lastly, we discuss one possible mechanism other than dust that might lead to increasingly blueshifted line profiles in SNeIIn, although the wavelength dependence of the asymmetry argues against this hypothesis in the case of SN2010jl.Comment: 6 pages, 4 figures, submitted to A