Hidden Double-Peaked Emitters in Seyfert 2 Galaxies

We present the detection of extremely broad, double-peaked, highly polarized Halpha emission lines in the nuclei of the well-known Seyfert 2 galaxies NGC 2110 and NGC 5252. These hidden broad Halpha emission lines, visible only in scattered light, are shown to display significant variability in strength and profile on timescales of <~ 1 yr. That the broad emission line exhibits variability in polarized flux also suggests that the scattering region must be very compact, possibly confined in a small number of electron clouds <~ 1 lt-yr in size. Our observational constraints place these clouds within ~10 pc of the nucleus with temperatures < 10^6 K and densities ~ 10^7 cm^-3, consistent with a region just outside the obscuring torus between the broad-line region and narrow-line region. These scattering clouds could arise from the clumpy torus itself. These findings and other properties indicate that NGC 2110 and NGC 5252 are the hidden counterparts to the broad-line double-peaked emission-line AGNs, whose examples include Arp 102B and 3C 332.Comment: 11 pages in emulateapj; ApJ vol. 711, 2010 March 10; v2: minor corrections to text for consistency with published versio

Controllable direction of liquid jets generated by thermocavitation within a droplet.

A high-velocity fluid stream ejected from an orifice or nozzle is a common mechanism to produce liquid jets in inkjet printers or to produce sprays among other applications. In the present research, we show the generation of liquid jets of controllable direction produced within a sessile water droplet by thermocavitation. The jets are driven by an acoustic shock wave emitted by the collapse of a hemispherical vapor bubble at the liquid-solid/substrate interface. The generated shock wave is reflected at the liquid-air interface due to acoustic impedance mismatch generating multiple reflections inside the droplet. During each reflection, a force is exerted on the interface driving the jets. Depending on the position of the generation of the bubble within the droplet, the mechanical energy of the shock wave is focused on different regions at the liquid-air interface, ejecting cylindrical liquid jets at different angles. The ejected jet angle dependence is explained by a simple ray tracing model of the propagation of the acoustic shock wave inside the droplet

Reconciling timber extraction with biodiversity conservation in tropical forests using reduced-impact logging

Over 20% of the world's tropical forests have been selectively logged, and large expanses are allocated for future timber extraction. Reduced-impact logging (RIL) is being promoted as best practice forestry that increases sustainability and lowers CO2 emissions from logging, by reducing collateral damage associated with timber extraction. RIL is also expected to minimize the impacts of selective logging on biodiversity, although this is yet to be thoroughly tested. We undertake the most comprehensive study to date to investigate the biodiversity impacts of RIL across multiple taxonomic groups. We quantified birds, bats and large mammal assemblage structures, using a before-after control-impact (BACI) design across 20 sample sites over a 5-year period. Faunal surveys utilized point counts, mist nets and line transects and yielded >250 species. We examined assemblage responses to logging, as well as partitions of feeding guild and strata (understorey vs. canopy), and then tested for relationships with logging intensity to assess the primary determinants of community composition. Community analysis revealed little effect of RIL on overall assemblages, as structure and composition were similar before and after logging, and between logging and control sites. Variation in bird assemblages was explained by natural rates of change over time, and not logging intensity. However, when partitioned by feeding guild and strata, the frugivorous and canopy bird ensembles changed as a result of RIL, although the latter was also associated with change over time. Bats exhibited variable changes post-logging that were not related to logging, whereas large mammals showed no change at all. Indicator species analysis and correlations with logging intensities revealed that some species exhibited idiosyncratic responses to RIL, whilst abundance change of most others was associated with time. Synthesis and applications. Our study demonstrates the relatively benign effect of reduced-impact logging (RIL) on birds, bats and large mammals in a neotropical forest context, and therefore, we propose that forest managers should improve timber extraction techniques more widely. If RIL is extensively adopted, forestry concessions could represent sizeable and important additions to the global conservation estate – over 4 million km2

Chandra High Energy Grating Observations of the Fe Ka Line Core in Type 2 Seyfert Galaxies: A Comparison with Type 1 Nuclei

We present a study of the core of the Fe Ka emission line at ~6.4 keV in a sample of type II Seyfert galaxies observed by the Chandra High Energy Grating (HEG). The sample consists of 29 observations of 10 unique sources. We present measurements of the Fe Ka line parameters with the highest spectral resolution currently available. In particular, we derive the most robust intrinsic line widths for some of the sources in the sample to date. We obtained a weighted mean FWHM of 2000 \pm 160 km/s for 8 out of 10 sources (the remaining sources had insufficient signal-to-noise). From a comparison with the optical emission-line widths obtained from spectropolarimetric observations, we found that the location of Fe Ka line-emitting material is a factor of ~0.7-11 times the size of the optical BLR. Furthermore, compared to 13 type I AGNs for which the best Fe Ka line FWHM constraints were obtained, we found no difference in the FWHM distribution or the mean FWHM, and this conclusion is independent of the central black hole mass. This result suggests that the bulk of the Fe Ka line emission may originate from a universal region at the same radius with respect to the gravitational radius, ~30,000 Rg on average. By examining the correlation between the Fe Ka luminosity and the [O IV] line luminosity, we found a marginal difference in the Fe K line flux between type I and type II AGNs, but the spread in the ratio of L(Fe) to L([O IV]) is about two orders of magnitude. Our results confirm the theoretical expectation that the Fe Ka emission-line luminosity cannot trivially be used as a proxy of the intrinsic AGN luminosity, unless a detailed comparison of the data with proper models is applied.Comment: 16 pages, 6 figures, and 2 tables, accepted for publication in Ap

The study of Seyfert 2 galaxies with and without infrared broad lines

From the literature, we construct from literature a sample of 25 Seyfert 2 galaxies (S2s) with a broad line region detected in near infrared spectroscopy and 29 with NIR BLR which was detected. We find no significant difference between the nuclei luminosity (extinction-corrected [OIII]~5007) and infrared color $\rm{f_{60}/f_{25}}$ between the two populations, suggesting that the non-detections of NIR BLR could not be due to low AGN luminosity or contamination from the host galaxy. As expected, we find significantly lower X-ray obscurations in Seyfert 2s with NIR BLR detection, supporting the unification scheme. However, such a scheme was challenged by the detection of NIR BLR in heavily X-ray obscured sources, especially in six of them with Compton-thick X-ray obscuration. The discrepancy could be solved by the clumpy torus model and we propose a toy model demonstrating that IR-thin X-ray-thick S2s could be viewed at intermediate inclinations, and compared with those IR-thick X-ray-thick S2s. We note that two of the IR-thin X-ray-thick S2s (NGC 1386 and NGC 7674) experienced X-ray transitions, i.e. from Compton-thin to Compton-thick appearance or vice versa based on previous X-ray observations, suggesting that X-ray transitions could be common in this special class of objects

Reflection in Seyfert Galaxies and the Unified Model of AGN

We present a deep study of the average hard X-ray spectra of Seyfert galaxies. We analyzed all public INTEGRAL IBIS/ISGRI data available on all the 165 Seyfert galaxies detected at z<0.2. Our final sample consists of 44 Seyfert 1's, 29 Seyfert 1.5's, 78 Seyfert 2's, and 14 Narrow Line Seyfert 1's. We derived the average hard X-ray spectrum of each subsample in the 17-250keV energy range. All classes of Seyfert galaxies show on average the same nuclear continuum, as foreseen by the zeroth order unified model, with a cut-off energy of Ec>200keV, and a photon index of Gamma ~1.8. Compton-thin Seyfert 2's show a reflection component stronger than Seyfert 1's and Seyfert 1.5's. Most of this reflection is due to mildly obscured (10^23 cm^-2 < NH < 10^24 cm^-2) Seyfert 2's, which have a significantly stronger reflection component (R=2.2^{+4.5}_{-1.1}) than Seyfert 1's (R<=0.4), Seyfert 1.5's (R<= 0.4) and lightly obscured (NH < 10^23 cm^-2) Seyfert 2's (R<=0.5). This cannot be explained easily by the unified model. The absorber/reflector in mildly obscured Seyfert 2's might cover a large fraction of the X-ray source, and have clumps of Compton-thick material. The large reflection found in the spectrum of mildly obscured Seyfert 2's reduces the amount of Compton-thick objects needed to explain the peak of the cosmic X-ray background. Our results are consistent with the fraction of Compton-thick sources being ~10%. The spectra of Seyfert 2's with and without polarized broad lines do not show significant differences, the only difference between the two samples being the higher hard X-ray and bolometric luminosity of Seyfert 2's with polarized broad lines. The average hard X-ray spectrum of Narrow line Seyfert 1's is steeper than those of Seyfert 1's and Seyfert 1.5's, probably due to a lower energy of the cutoff.Comment: 19 pages, accepted for publication in Astronomy and Astrophysics, final versio

Mrk 609: resolving the circum-nuclear structure with near-infrared integral field spectroscopy

We present first results of near infrared J and H+K ESO-SINFONI integral field spectroscopy of the composite starburst/Seyfert 1.8 galaxy Mrk 609. The data were taken during the science verification period of SINFONI. We aim to investigate the morphology and excitation conditions within the central 2 kpc. Additional Nobeyama 45 m CO(1-0) data are presented, which we used to estimate the molecular gas mass. The source was selected from a sample of adaptive optics suitable, SDSS/ROSAT based, X-ray bright AGN with redshifts of 0.03 < z < 1. This sample allows for a detailed study of the NIR properties of the nuclear and host environments with high spectral and spatial resolution. Our NIR data reveal a complex emission-line morphology, possibly associated with a nuclear bar seen in the reconstructed continuum images. The detections of [SiVI] and a broad Pa alpha component are clear indicators for the presence of an accreting super-massive black hole at the center of Mrk 609. In agreement with previous observations we find that the circum-nuclear emission is not significantly extincted. The analysis of the high angular resolution rotational-vibrational molecular hydrogen and forbidden [FeII] emission reveals a LINER character of the nucleus. The large H_2 gas mass deduced from the CO(1-0) observation provides the fuel needed to feed the starburst and Seyfert activity in Mrk 609. High angular resolution imaging spectroscopy provides an ideal tool to resolve the nuclear and starburst contribution in active galaxies. We show that Mrk 609 exhibits LINER features, that appear to be hidden in larger aperture visible/NIR spectra.Comment: published by A&A, 19 pages, 16 figures, version with high resolution figures is available via http://www.ph1.uni-koeln.de/~zuther/mrk609.pd

Relación entre el clima social familiar y autoestima en estudiantes del tercer, cuarto y quinto grado de secundaria de la Institución Educativa Santa María Reyna – Huancayo

La investigación titulada “Relación entre el clima social familiar y autoestima en estudiantes del tercer, cuarto y quinto grado de secundaria de la Institución Educativa Santa María Reyna - Huancayo”, tuvo como objetivo determinar la relación que existe entre el clima social familiar y la autoestima en las estudiantes del tercer, cuarto y quinto grado de educación secundaria del mencionado colegio. La muestra de esta investigación asciende a 192 estudiantes del sexo femenino, que oscilan entre 13 y 17 años de edad. Se utilizó el método científico, el diseño fue no experimental transaccional – correlacional; y es de tipo descriptivo. Se aplicó la escala de clima social familiar de Rudolf H. Moos y el cuestionario de autoestima de Stanley Coopersmith. Los resultados señalan que existe una relación entre clima social familiar y autoestima con un coeficiente de correlación de Pearson de 0.878. Asimismo, el nivel de clima social familiar es medio con un 49%. El nivel de autoestima de las estudiantes es promedio con un 41.7%. La relación del clima social familiar medio y la autoestima promedio es mayor con un 23%. Se observa que a mejor clima social familiar mayor será la autoestima de las estudiantes

Accelerated amyloid deposition, neurofibrillary degeneration and neuronal loss in double mutant APP/tau transgenic mice

Even though the idea that amyloid beta peptide accumulation is the primary event in the pathogenesis of Alzheimer's disease has become the leading hypothesis, the causal link between aberrant amyloid precursor protein processing and tau alterations in this type of dementia remains controversial. We further investigated the role of beta-amyloid production/deposition in tau pathology and neuronal cell death in the mouse brain by crossing Tg2576 and VLW lines expressing human mutant amyloid precursor protein and human mutant tau, respectively. The resulting double transgenic mice showed enhanced amyloid deposition accompanied by neurofibrillary degeneration and overt neuronal loss in selectively vulnerable brain limbic areas. These findings challenge the idea that tau pathology in Alzheimer's disease is merely a downstream effect of amyloid production/deposition and suggest that reciprocal interactions between beta-amyloid and tau alterations may take place in vivo

Inundabilidad en cauces de alta pendiente teniendo en cuenta el transporte de sedimentos

El objetivo del presente estudio es determinar el efecto que provocan los sedimentos en los cauces de alta pendiente. Se quiere obtener cual será la influencia en comparación al caso de no tenerlos en cuenta, como se hace generalmente. Cabe recordar que en estos tipos de cauces la influencia de los sedimentos puede llegar a ser muy significativa ya que debido a la alta pendiente pueden llegar a arrastrar mucho más material que en otros ríos de menor pendiente, lo que puede cambiar los resultados esperados. La zona del estudio es la perteneciente a la cuenca de la riera de la Alforja, una cuenca interna catalana situada en la comarca del Baix Camp en la provincia de Tarragona