28 research outputs found

    AzTEC 1.1 mm OBSERVATIONS OF THE MBM12 MOLECULAR CLOUD

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    This is the published version, also available her: http://dx.doi.org/10.1088/0004-637X/746/1/11.We present 1.1 mm observations of the dust continuum emission from the MBM12 high-latitude molecular cloud observed with the Astronomical Thermal Emission Camera (AzTEC) mounted on the James Clerk Maxwell Telescope on Mauna Kea, Hawaii. We surveyed 6.34 deg2 centered on MBM12, making this the largest area that has ever been surveyed in this region with submillimeter and millimeter telescopes. Eight secure individual sources were detected with a signal-to-noise ratio of over 4.4. These eight AzTEC sources can be considered to be real astronomical objects compared to the other candidates based on calculations of the false detection rate. The distribution of the detected 1.1 mm sources or compact 1.1 mm peaks is spatially anti-correlated with that of the 100 Όm emission and the 12CO emission. We detected the 1.1 mm dust continuum emitting sources associated with two classical T Tauri stars, LkHα262 and LkHα264. Observations of spectral energy distributions (SEDs) indicate that LkHα262 is likely to be Class II (pre-main-sequence star), but there are also indications that it could be a late Class I (protostar). A flared disk and a bipolar cavity in the models of Class I sources lead to more complicated SEDs. From the present AzTEC observations of the MBM12 region, it appears that other sources detected with AzTEC are likely to be extragalactic and located behind MBM12. Some of these have radio counterparts and their star formation rates are derived from a fit of the SEDs to the photometric evolution of galaxies in which the effects of a dusty interstellar medium have been included

    Short-term relationships between emergency hospital admissions for respiratory and cardiovascular diseases and fine particulate air pollution in Beirut, Lebanon

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    International audienceHigh levels of major outdoor air pollutants have been documented in Lebanon, but their health effects remain unknown. The Beirut Air Pollution and Health Effects study aimed to determine the relationship between short-term variations in ambient concentrations of particulate matter (PM10 and PM2.5) and emergency hospital admissions in the city of Beirut, and whether susceptible groups are more greatly affected. An autoregressive Poisson model was used to evaluate the association between daily concentrations of particulate matter and respiratory and cardiovascular emergency hospital admissions after controlling for confounders. All variables were measured during 1 year from January 2012 to December 2012. Relative risks of admissions for respiratory and cardiovascular diseases were calculated for an increase in 10 ÎŒg.m−3 of pollutant concentrations. Total respiratory admissions were significantly associated with the levels of PM10 (1.012 [95 % CI 1.004–1.02]) per 10 ÎŒg.m−3 rise in daily mean pollutant concentration for PM10 and 1.016 [95 % CI 1.000–1.032] for PM2.5 on the same day. With regard to susceptible groups, total respiratory admissions were associated with PM2.5 and PM10 within the same day in children (relative risk (RR), 1.013 and 1.014; 95 % confidence interval, 0.985–1.042 and 1.000–1.029 for PM2.5 and PM10, respectively). Moreover, a nearly significant association was found between particles and total circulatory admissions for adults and elderly groups in the same day. These results are similar to other international studies. Therefore, air pollution control is expected to reduce the number of admissions of these diseases in Lebanon
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