Detection of Pre-Shock Dense Circumstellar Material of SN 1978K

The supernova SN 1978K has been noted for its lack of emission lines broader than a few thousand km/s since its discovery in 1990. Modeling of the radio spectrum of the peculiar SN 1978K indicates the existence of HII absorption along the line of sight. To determine the nature of this absorbing region, we have obtained a high-dispersion spectrum of SN 1978K at the wavelength range 6530--6610 \AA. The spectrum shows not only the moderately broad H-alpha emission of the supernova ejecta but also narrow nebular H-alpha and [N II] emission. The high [N II]6583/H-alpha ratio, 0.8-1.3, suggests that this radio absorbing region is a stellar ejecta nebula. The expansion velocity and emission measure of the nebula are consistent with those seen in ejecta nebulae of luminous blue variables. Previous low-dispersion spectra have detected a strong [N II]5755 line, indicating an electron density of 3-12x10^5 cm^{-3}. We argue that this stellar ejecta nebula is probably part of the pre-shock dense circumstellar envelope of SN 1978K. We further suggest that SN 1997ab may represent a young version of SN 1978K.Comment: 12 pages, 1 figure, accepted for publication in the ApJ Letter

Pliocene-Pleistocene radiolarian events and magnetostratigraphic calibrations for the tropical Indian Ocean

A composite of four piston cores from the Central Indian Basin and adjacent Ninetyeast Ridge has yielded a continuous magnetobiostratigraphic reference section for most of the Pliocene and the Pleistocene (0.0–4.5 Ma). We identified thirty-three radiolarian events (first- or last-occurrences), and precisely correlated each event to the Neogene geomagnetic polarity time scale. Thirteen of these events are based on revised taxonomic studies of the genera Anthocyrtidium and Pterocorys. Some events show significant departures from synchroneity: five of the radiolarian first-appearances and seven of the last-appearances are time-transgressive by 0.4 m.y. or greater. We here propose a revised, eleven-fold radiolarian zonation for the Pliocene-Pleistocene, using zonal boundaries defined by events which are easily recognized and are demonstrably synchronous in the tropical Indo-Pacific. The sequence of faunal and floral events reported in this paper will allow high-resolution biostratigraphic correlations within the tropical Indian Ocean; however, the same sequence of events is not necessarily applicable to other tropical or extratropical regions

Structure of Supergiant Shells in the Large Magellanic Cloud

Nine supergiant shells (SGSs) have been identified in the Large Magellanic Cloud (LMC) based on H-alpha images, and twenty-three SGSs have been reported based on HI 21-cm line observations, but these sets do not always identify the same structures. We have examined the physical structure of the optically identified SGSs using HI channel maps and P-V diagrams to analyze the gas kinematics. There is good evidence for seven of the nine optically identified SGSs to be true shells. Of these seven H-alpha SGSs, four are the ionized inner walls of HI SGSs, while three are an ionized portion of a larger and more complex HI structure. All of the H-alpha SGSs are identified as such because they have OB associations along the periphery or in the center, with younger OB associations more often found along the periphery. After roughly 12 Myrs, if no new OB associations have been formed a SGS will cease to be identifiable at visible wavelengths. Thus, the presence and location of ionizing sources is the main distinction between shells seen only in HI and those also seen in H-alpha. Based on our analysis, H-alpha observations alone cannot unambiguously identify SGSs, especially in distant galaxies.Comment: 26 pages, 16 figures, accepted for publication in the Astrophysical Journal Supplemen

An X-ray absorption analysis of the high-velocity system in NGC 1275

We present an X-ray absorption analysis of the high-velocity system (HVS) in NGC 1275 using results from a deep 200 ks Chandra observation. We are able to describe the morphology of the HVS in more detail than ever before. We present an HST image for comparison, and note close correspondence between the deepest X-ray absorption and the optical absorption. A column density map of the HVS shows an average column density NH of 1x10^21 cm^-2 with a range from ~5x10^20 to 5x10^21 cm^-2. From the NH map we calculate a total mass for the absorbing gas in the HVS of (1.32+-0.05)x10^9 solar masses at solar abundance. 75 per cent of the absorbing mass is contained in the four regions of deepest absorption. We examine temperature maps produced by spectral fitting and find no direct evidence for shocked gas in the HVS. Using deprojection methods and the depth of the observed absorption, we are able to put a lower limit on the distance of the HVS from the nucleus of 57 kpc, showing that the HVS is quite separate from the body of NGC 1275.Comment: 6 pages, 5 colour figures, accepted by MNRA

Plan d’action québécois en santé mentale : contextes de mise en oeuvre et éléments d’impact sur l’organisation des services de première ligne et les modes de collaboration

Depuis 2005, le Plan d’action en santé mentale oriente le développement et l’organisation des services en santé mentale au Québec. En conjonction avec d’autres réformes modifiant l’économie générale du système de santé, il vise en particulier à favoriser une réponse adéquate aux troubles mentaux courants. Cette préoccupation appelle une transformation de l’offre de services en première ligne. Une analyse de différents contextes dans lesquels opèrent ces changements permet une réflexion sur les principaux facteurs susceptibles d’influencer l’actualisation de certaines propositions du Plan d’action et sur l’évolution des modes de collaboration, un pré requis à la mise en place des réseaux locaux de services.Since 2005, the Mental Health Action Plan maps out development and reorganization of mental health services in Québec. With concurrent reforms affecting the overall layout of the health care system, the Action Plan especially seeks to improve the management of common mental disorders. This particular concern calls for transformations at the primary care level. Contextual analysis of contrasting settings allows the identification of the main determinants in this actual process of change and in the ways collaborative issues are addressed.Desde 2005, el Plan de Acción de Salud Mental orienta el desarrollo y la organización de los servicios de salud mental en Quebec. Junto con otras reformas que modifican la economía general del sistema de salud, el plan busca en particular favorecer una respuesta adecuada a los trastornos mentales comunes. Esta preocupación implica una transformación de la oferta de servicios de primer nivel. Un análisis de diferentes contextos en los que operan estos cambios permite una reflexión acerca de los principales factores susceptibles de influir en la actualización de ciertas proposiciones del Plan de Acción y en la evolución de las formas de colaboración, un prerrequisito para la puesta en marcha de las redes locales de servicios.Desde 2005, o Plano de Ação em Saúde Mental orienta o desenvolvimento e a organização dos serviços em saúde mental no Quebec. Em conjunto com outras reformas que modificam a economia geral do sistema de saúde, ele visa principalmente favorecer uma resposta adequada aos transtornos mentais correntes. Esta preocupação demanda uma transformação da oferta de serviços primários. Uma análise de diferentes contextos nos quais operam estas mudanças permite uma reflexão sobre os principais fatores susceptíveis de influenciar a atualização de algumas propostas do Plano de Ação e sobre a evolução dos modos de colaboração, um pré-requisito para a criação das redes locais de serviços

Massive star formation around I05345+3157 -- I. The dense gas

We present observations of the intermediate to massive star-forming region I05345+3157 using the molecular line tracer CS(2-1) with CARMA to reveal the properties of the dense gas cores. Seven gas cores are identified in the integrated intensity map of CS(2-1). Among these, core 1 and core 3 have counterparts in the 2.7 millimeter continuum data. We suggest that core 1 and core 3 are star-forming cores that may already or will very soon harbor young massive protostars. The total masses of core 1 estimated from the LTE method and dust emission by assuming a gas-to-dust ratio are 5 +- 1 solar masses and 18 +- 6 solar masses, and that of core 3 are 15 +- 7 solar masses and 11 +- 3 solar masses. The spectrum of core 3 shows blue-skewed self-absorption, which suggests gas infall -- a collapsing core. The observed broad linewidths of the seven gas cores indicate non-thermal motions. These non-thermal motions can be interactions with nearby outflows or due to the initial turbulence; the former is observed, while the role of initial turbulence is less certain. Finally, the virial masses of the gas cores are larger than the LTE masses, which for a bound core implies a requirement on the external pressure of ~ 10^8 K/cm^3. The cores have the potential to further form massive stars.Comment: Accepted for publication in MNRA

High and Intermediate-Mass Young Stellar Objects in the Large Magellanic Cloud

(Abridged) Photometry of archival Spitzer observations of the Large Magellanic Cloud (LMC) are used to search for young stellar objects (YSOs). Simple mid-infrared selection criteria were used to exclude most normal and evolved stars and background galaxies. We identify a sample of 2,910 sources in the LMC that could potentially be YSOs. We then simultaneously considered images and photometry from the optical through mid-IR wavelengths to assess the source morphology, spectral energy distribution (SED), and the surrounding interstellar environment to determine the most likely nature of each source. From this examination of the initial sample, we suggest 1,172 sources are most likely YSOs and 1,075 probable background galaxies, consistent with expectations based on SWIRE survey data. Spitzer IRS observations of 269 of the brightest YSOs from our sample have confirmed that ~>95% are indeed YSOs. A comprehensive search for YSOs in the LMC has also been carried out by the SAGE team. There are three major differences between these two searches. (1) In the common region of color-magnitude space, ~850 of our 1,172 probable YSOs are missed in the SAGE YSO catalog because their conservative point source identification criteria have excluded YSOs superposed on complex diffuse emission. (2) About 20-30% of the YSOs identified by the SAGE team are sources we classify as background galaxies. (3) the SAGE YSO catalog identifies YSO in parts of color-magnitude space that we excluded and thus contains more evolved or fainter YSOs missed by our analysis. Finally, the mid-IR luminosity functions of our most likely YSO candidates in the LMC can be well described by N(L) propto L^-1, which is consistent with the Salpeter initial mass function if a mass-luminosity relation of L propto M^2.4 is adopted.Comment: Accepted for publication in the Astrophysical Journal Supplement Series. 67 pages, 20 figures, 16 tables. A version with full resolution figures is available at http://www.astro.illinois.edu/~gruendl/LMC_YSO.pdf. Full tables available on request or through ApJ