115 research outputs found

    The Warped Nuclear Disk of Radio Galaxy 3C 449

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    Among radio galaxies containing nuclear dust disks, the bipolar jet axis is generally observed to be perpendicular to the disk major axis. The FR I radio source 3C 449 is an outlier to this statistical majority, as it possesses a nearly parallel jet/disk orientation on the sky. We examine the 600 pc dusty disk in this galaxy with images from the Hubble Space Telescope. We find that a colormap of the disk exhibits a twist in its isocolor contours (isochromes). We model the colormap by integrating galactic starlight through an absorptive disk, and find that the anomalous twist in the isochromes can be reproduced in the model with a vertically thin, warped disk. The model predicts that the disk is nearly perpendicular to the jet axis within 100 pc of the nucleus. We discuss physical mechanisms capable of causing such a warp. We show that precessional models or a torque on the disk arising from a possible binary black hole in the AGN causes precession on a timescale that is too long to account for the predicted disk morphology. However, we estimate that the pressure in the X-ray emitting interstellar medium is large enough to perturb the disk, and argue that jet-driven anisotropy in the excited ISM may be the cause of the warp. In this way, the warped disk in 3C 449 may be a new manifestation of feedback from an active galactic nucleus.Comment: Accepted for publication in Ap

    Young AGN outburst running over older X-ray cavities

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    Although the energetic feedback from active galactic nuclei (AGN) is believed to have a profound effect on the evolution of galaxies and clusters of galaxies, details of the AGN heating remain elusive. Here, we study NGC 193 - a nearby lenticular galaxy - based on X-ray (Chandra) and radio (VLA and GMRT) observations. These data reveal the complex AGN outburst history of the galaxy: we detect a pair of inner X-ray cavities, an outer X-ray cavity, a shock front, and radio lobes extending beyond the inner cavities. We suggest that the inner cavities were produced ~78 Myr ago by a weaker AGN outburst, while the outer cavity, the radio lobes, and the shock front are due to a younger (13-26 Myr) and (4-8) times more powerful outburst. Combining this with the observed morphology of NGC 193, we conclude that NGC 193 likely represents the first example of a second, more powerful, AGN outburst overrunning an older, weaker outburst. These results help to understand how the outburst energy is dissipated uniformly in the core of galaxies, and therefore may play a crucial role in resolving how AGN outbursts suppress the formation of large cooling flows at cluster centers.Comment: 6 pages, 3 figures, 1 table, accepted for publication in ApJ

    STIS spectroscopy of the emission line gas in the nuclei of nearby FR-I galaxies

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    We present the results of the analysis of a set of medium resolution spectra, obtained by the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, of the emission line gas present in the nuclei of a complete sample of 21 nearby, early-type galaxies with radio jets (the UGC FR-I Sample). For each galaxy nucleus we present spectroscopic data in the region of H-alpha and the dervived kinematics. We find that in 67% of the nuclei the gas appears to be rotating and, with one exception, the cases where rotation is not seen are either face on or have complex central morphologies. We find that in 62% of the nuclei the fit to the central spectrum is improved by the inclusion of a broad component. The broad components have a mean velocity dispersion of 1349 +/- 345 km\s and are redshifted from the narrow line components (assuming an origin in H-alpha) by 486 +/- 443 km\s.Comment: 119 pages, 26 figures, ApJS Accepted, version with full figures available at http://www.astro.columbia.edu/~jake/pub/fr1datapaper.pd

    An infrared survey of brightest cluster galaxies: Paper I

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    We report on an imaging survey with the Spitzer Space Telescope of 62 brightest cluster galaxies with optical line emission. These galaxies are located in the cores of X-ray luminous clusters selected from the ROSAT All-Sky Survey. We find that about half of these sources have a sign of excess infrared emission; 22 objects out of 62 are detected at 70 microns, 18 have 8 to 5.8 micron flux ratios above 1.0 and 28 have 24 to 8 micron flux ratios above 1.0. Altogether 35 of 62 objects in our survey exhibit at least one of these signs of infrared excess. Four galaxies with infrared excesses have a 4.5/3.6 micron flux ratio indicating the presence of hot dust, and/or an unresolved nucleus at 8 microns. Three of these have high measured [OIII](5007A)/Hbeta flux ratios suggesting that these four, Abell 1068, Abell 2146, and Zwicky 2089, and R0821+07, host dusty active galactic nuclei (AGNs). 9 objects (including the four hosting dusty AGNs) have infrared luminosities greater than 10^11 L_sol and so can be classified as luminous infrared galaxies (LIRGs). Excluding the four systems hosting dusty AGNs, the excess mid-infrared emission in the remaining brightest cluster galaxies is likely related to star formation.Comment: accepted for publication in ApJ

    Catholic school governance in the twenty-first century: continuity, incongruity and challenge

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    This study has two main aspects: first, it reports the results of a survey of ninety nine governors working in Roman Catholic primary and secondary schools situated in four English Catholic dioceses, and publishes hitherto unknown information about them; and, second, it examines how, in seeking to maintain a distinctive educational ethos, these governors are responding both to the legislative changes of the last twenty years, and to changes in English social and cultural attitudes. It shows how these responses calibrate with the perceptions of those appointed by the Catholic bishops to oversee the conduct of the schools – the diocesan directors – six of whom were interviewed, together with an official with a national perspective. The study shows that, whilst there are powerful elements of continuity in the Catholic Church’s view of the nature and purpose of schools, a number of incongruities are now arising as a result of the enhanced powers given to governing bodies since 1980, and that the diocesan authorities are not as effective in providing support for their schools as are the local authorities (LAs). This trend appears to be having an adverse effect on what should be the schools’ distinctive nature, and could therefore be preparing the ground for challenges between dioceses and schools. One of the key areas involved is that of senior staff appointments, where the existing policy position appears unsustainable. Others concern the expectations some governors have of the need for teachers to practise high levels of sexual morality in their private lives, and the distinctive Catholic ethos which governors believe their schools manifest

    Objective assessment of blood and lymphatic vessel invasion and association with macrophage infiltration in cutaneous melanoma

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    The aims of this study were to investigate the role of vascular invasion (blood and lymphatic), vessel density and the presence of tumour-associated macrophages as prognostic markers in 202 cutaneous melanoma patients. Sections of primary melanoma were stained with lymphatic-specific antibody D2-40 to assess lymphatic vessel invasion and density in intratumoural and peritumoural areas; an antibody against endothelial marker CD34 was used to determine blood vessel invasion and density, and an antibody against CD68 was used to determine macrophage counts. Immunohistochemically determined vascular invasion (combined blood and lymphatic) was compared with that determined using haematoxylin and eosin (H&E) staining. The use of immunohistochemistry increased detection of vascular invasion from 8–30% of patients, and histological exam of H&E-stained tissue was associated with a false positive rate of 64%. Lymphatic vessel invasion occurred at a much higher frequency than blood vessel invasion (27 and 4% of patients, respectively). Although immunohistochemically detected vessel invasion was significantly associated with histological markers of adverse prognosis, such as increased Breslow thickness, ulceration and mitotic rate (all P<0.001), no associations with relapse-free or overall survival were observed. High macrophage counts were significantly associated with markers of aggressive disease, such as Breslow thickness, ulceration and mitotic rate (P<0.001, P<0.001, P=0.005, respectively), and lymphatic vessel invasion and high microvessel density (P=0.002 and P=0.003, respectively). These results suggest that vascular invasion is more accurately detected using immunohistochemistry and occurs predominantly via lymphatic vessels. The association of vessel characteristics with histological characteristics of the primary melanoma provides evidence for their biological importance in melanoma, but that they were not associated with clinical outcome attests to the value of existing histological prognostic biomarkers. We note that a high macrophage count may be associated with neovascularisation and primary tumour growth, and may also promote invasion through lymphatic vessels

    HST/ACS Emission Line Imaging of Low Redshift 3CR Radio Galaxies I: The Data

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    We present 19 nearby (z<0.3) 3CR radio galaxies imaged at low- and high-excitation as part of a Cycle 15 Hubble Space Telescope snapshot survey with the Advanced Camera for Surveys. These images consist of exposures of the H-alpha (6563 \AA, plus [NII] contamination) and [OIII] 5007 \AA emission lines using narrow-band linear ramp filters adjusted according to the redshift of the target. To facilitate continuum subtraction, a single-pointing 60 s line-free exposure was taken with a medium-band filter appropriate for the target's redshift. We discuss the steps taken to reduce these images independently of the automated recalibration pipeline so as to use more recent ACS flat-field data as well as to better reject cosmic rays. We describe the method used to produce continuum-free (pure line-emission) images, and present these images along with qualitative descriptions of the narrow-line region morphologies we observe. We present H-alpha+[NII] and [OIII] line fluxes from aperture photometry, finding the values to fall expectedly on the redshift-luminosity trend from a past HST/WFPC2 emission line study of a larger, generally higher redshift subset of the 3CR. We also find expected trends between emission line luminosity and total radio power, as well as a positive correlation between the size of the emission line region and redshift. We discuss the associated interpretation of these results, and conclude with a summary of future work enabled by this dataset.Comment: 18 pages, 12 figures, accepted for publication in ApJ

    A retrospective analysis of endocrine disease in sphingosine-1-phosphate lyase insufficiency: case series and literature review

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    Primary adrenal insufficiency; Primary hypothyroidism; Sphingosine-1-phosphate lyaseInsuficiencia suprarrenal primaria; Hipotiroidismo primario; Esfingosina-1-fosfato liasaInsuficiència suprarenal primària; Hipotiroïdisme primari; Esfingosina-1-fosfat liasaSphingosine-1-phosphate lyase (SGPL1) insufficiency syndrome (SPLIS) is an autosomal recessive multi-system disorder, which mainly incorporates steroid-resistant nephrotic syndrome and primary adrenal insufficiency. Other variable endocrine manifestations are described. In this study, we aimed to comprehensively annotate the endocrinopathies associated with pathogenic SGPL1 variants and assess for genotype–phenotype correlations by retrospectively reviewing the reports of endocrine disease within our patient cohort and all published cases in the wider literature up to February 2022. Glucocorticoid insufficiency in early childhood is the most common endocrine manifestation affecting 64% of the 50 patients reported with SPLIS, and a third of these individuals have additional mineralocorticoid deficiency. While most individuals also have nephrotic syndrome, SGPL1 variants also account for isolated adrenal insufficiency at presentation. Primary gonadal insufficiency, manifesting with microphallus and cryptorchidism, is reported in less than one-third of affected boys, all with concomitant adrenal disease. Mild primary hypothyroidism affects approximately a third of patients. There is paucity of data on the impact of SGPL1 deficiency on growth, and pubertal development, limited by the early and high mortality rate (approximately 50%). There is no clear genotype–phenotype correlation overall in the syndrome, with variable disease penetrance within individual kindreds. However, with regards to endocrine phenotype, the most prevalent disease variant p.R222Q (affecting 22%) is most consistently associated with isolated glucocorticoid deficiency.To conclude, SPLIS is associated with significant multiple endocrine disorders. While endocrinopathy in the syndrome generally presents in infancy, late-onset disease also occurs. Screening for these is therefore warranted both at diagnosis and through follow-up.This work was supported by the Medical Research Council (MRC) UK Clinical Academic Research Partner Grant (MR/T02402X/1, 2019 to R P), Barts and the London Charity (MGU0361, 2017 to L A M), Barts and the London Charity Research Fellow Grant (MGU0528 to R K), Medical Research Council (MRC) UK Clinical Research Training Fellowship Grant (MR/W015935/1 to RK), Government of Trinidad and Tobago Research Fellowship (to A M) and Wellcome Trust (209328/Z/17/Z to J C A)
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