137 research outputs found

    U B V R I Photometry of Stellar Structures throughout the Disk of the Barred Galaxy NGC 3367

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    We report new detailed surface U, B, V, R, and I photometry of 81 stellar structures in the disk of the barred galaxy NGC 3367. The images show many different structures indicating that star formation is going on in the most part of the disk. NGC 3367 is known to have a very high concentration of molecular gas distribution in the central regions of the galaxy and bipolar synchrotron emission from the nucleus with two lobes (at 6 kpc) forming a triple structure similar to a radio galaxy. We have determined the U, B, V, R, and I magnitudes and U - B, B - V, U - V, and V - I colors for the central region (nucleus), a region which includes supernovae 2003 AA, and 79 star associations throughout NGC 3367. Estimation of ages of star associations is very difficult due to several factors, among them: filling factor, metallicity, spatial distribution of each structure and the fact that we estimated the magnitudes with a circular aperture of 16 pixels in diameter, equivalent to 6.81.46''.8\sim1.4 kpc. However, if the colors derived for NGC 3367 were similar to the colors expected of star clusters with theoretical evolutionary star tracks developed for the LMC and had a similar metallicity, NGC 3367 show 51 percent of the observed structures with age type SWB I (few tens of Myrs), with seven sources outside the bright surface brightness visible disk of NGC 3367.Comment: Accepted for publication (abr 2007) in The Astronomical Journal (July 2007 issue

    Fabry Perot Halpha Observations of the Barred Spiral NGC 3367

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    We report the gross properties of the velocity field of the barred spiral galaxy NGC 3367. The following values were found: inclination with respect to the plane of the sky, i=30 deg; position angle (PA) of receding semi major axis PA=51 and systemic velocity V(sys)=3032 km/s. Large velocity dispersion are observed of upt o 120 km/s in the nuclear region, of up to 70 km/s near the eastern bright sources just beyond the edge of the stellar bar where three spiral arms seem to start and in the western bright sources at about 10 kpc. Deviations from normal circular velocities are observed from all the disk but mainly from the semi circle formed by the string of south western Halpha sources. An estimate of the dynamical mass is M(dyn)=2x10^11 Msolar.Comment: Accepted to be published in May 2001 issue in the A.J. 19 pages, 7 figure

    Volcanic eruption of Cumbre Vieja, La Palma, Spain: A first insight to the particulate matter injected in the troposphere

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    The volcanic eruption of Cumbre Vieja (La Palma Island, Spain), started on 19 September 2021 and was declared terminated on 25 December 2021. A complete set of aerosol measurements were deployed around the volcano within the first month of the eruptive activity. This paper describes the results of the observations made at Tazacorte on the west bank of the island where a polarized micro-pulse lidar was deployed. The analyzed two-and-a-half months (16 October–31 December) reveal that the peak height of the lowermost and strongest volcanic plume did not exceed 3 km (the mean of the hourly values is 1.43 ± 0.45 km over the whole period) and was highly variable. The peak height of the lowermost volcanic plume steadily increased until week 11 after the eruption started (and 3 weeks before its end) and started decreasing afterward. The ash mass concentration was assessed with a method based on the polarization capability of the instrument. Two days with a high ash load were selected: The ash backscatter coefficient, aerosol optical depth, and the volume and particle depolarization ratios were, respectively, 3.6 (2.4) Mm−1sr−1, 0.52 (0.19), 0.13 (0.07) and 0.23 (0.13) on 18 October (15 November). Considering the limitation of current remote sensing techniques to detect large-to-giant particles, the ash mass concentration on the day with the highest ash load (18 October) was estimated to have peaked in the range of 800–3200 μg m−3 in the lowermost layer below 2.5 km.This research was funded by the Spanish Ministry of Science and Innovation (PID2020- 118793GA-I00, PID2019-104205GB-C21, EQC2018-004686-P and PID2019-103886RB-I00), the H2020 program from the European Union (GA no. 19ENV04, 654109, 778349, 871115 and 101008004), and the Unit of Excellence “María de Maeztu” (MDM-2017-0737) financed by the Spanish State Research Agency (AEI). The authors wish to thank ACTRIS, AEROSPAIN and Junta de Castilla y León (ref: VA227P20) for supporting the calibration of the AERONET sun photometers used in this publication, and also to Ayuntamiento de Tazacorte, Ayuntamiento de Fuencaliente and Cabildo Insular de La Palma for their help in terms of infrastructure and logistics. M.-Á.L.-C. and C.V.C.-P. are supported by the INTA predoctoral contract program. E.J.W. is funded by the NASA Radiation Sciences Program and Earth Observing System.Peer ReviewedArticle signat per 16 autors/es: Michaël Sicard (1,2), Carmen Córdoba-Jabonero (3), Africa Barreto (4), Ellsworth J. Welton (5), Cristina Gil-Díaz (1),Clara V. Carvajal-Pérez (3), Adolfo Comerón (1), Omaira García (4), Rosa García (6), María-Ángeles López-Cayuela (3),Constantino Muñoz-Porcar (1), Natalia Prats (4), Ramón Ramos (4), Alejandro Rodríguez-Gómez (1), Carlos Toledano (7), Carlos Torres (4) // (1) CommSensLab, Department of Signal Theory and Communications, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain; (2) Ciències i Tecnologies de l’Espai-Centre de Recerca de l’Aeronàutica i de l’Espai/Institut d’Estudis Espacials de Catalunya (CTE-CRAE/IEEC), Universitat Politècnica de Catalunya, 08034 Barcelona, Spain; (3) Atmospheric Research and Instrumentation Branch, Instituto Nacional de Técnica Aeroespacial (INTA), 28850 Torrejon de Ardoz, Spain; (4) Izaña Atmospheric Research Center, State Meteorological Agency of Spain (AEMET), 38001 Santa Cruz de Tenerife, Spain: (5) Code 612, Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, MD 20771, USA; (6) TRAGSATEC, 28006 Madrid, Spain; (7) Group of Atmospheric Optics, Universidad de Valladolid, 47011 Valladolid, SpainPostprint (published version

    Aerosol characterisation in the subtropical eastern North Atlantic region using long-term AERONET measurements

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    A comprehensive characterisation of atmospheric aerosols in the subtropical eastern North Atlantic has been carried out using long-term ground-based Aerosol Robotic NETwork (AERONET) photometric observations over the period 2005–2020 from a unique network made up of four stations strategically located from sea level to 3555 m on the island of Tenerife. This site can be considered a sentinel for the passage of airmasses going to Europe from Africa, and therefore the aerosol characterisation performed here adds important information for analysing their evolution during their path toward Northern Europe. Two of these stations (Santa Cruz de Tenerife – SCO – at sea level and La Laguna – LLO – at 580 m a.s.l.) are located within the marine atmospheric boundary layer (MABL), and the other two (Izaña – IZO – at 2373 m a.s.l. and Teide Peak – TPO – at 3555 m a.s.l.) are high mountain stations within the free troposphere (FT). Monthly climatology of the aerosol optical depth (AOD), Ångström exponent (AE), aerosol concentration, size distribution and aerosol optical properties has been obtained for the MABL and FT. Measurements that are quite consistent across the four sites have been used to categorise the main atmospheric scenarios, and these measurements confirm an alternation between predominant background conditions and predominant dust-loaded Saharan air mass conditions caused by seasonal dust transport over the subtropical North Atlantic. Background conditions prevail in the MABL and FT for most of the year, while dust-laden conditions dominate in July and August.The authors also acknowledge the support from ACTRIS, Ministerio de Ciencia e Innovación, Spain, through the projects SYNERA (PID2020-118793GA-I00) and ePOLAAR (RTI2018-097864-BI00) and from Junta de Castilla y León (grant no. VA227P20)

    Izaña Atmospheric Research Center. Activity Report 2019-2020

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    Editors: Emilio Cuevas, Celia Milford and Oksana Tarasova.[EN]The Izaña Atmospheric Research Center (IARC), which is part of the State Meteorological Agency of Spain (AEMET), is a site of excellence in atmospheric science. It manages four observatories in Tenerife including the high altitude Izaña Atmospheric Observatory. The Izaña Atmospheric Observatory was inaugurated in 1916 and since that date has carried out uninterrupted meteorological and climatological observations, contributing towards a unique 100-year record in 2016. This reports are a summary of the many activities at the Izaña Atmospheric Research Center to the broader community. The combination of operational activities, research and development in state-of-the-art measurement techniques, calibration and validation and international cooperation encompass the vision of WMO to provide world leadership in expertise and international cooperation in weather, climate, hydrology and related environmental issues.[ES]El Centro de Investigación Atmosférica de Izaña (CIAI), que forma parte de la Agencia Estatal de Meteorología de España (AEMET), representa un centro de excelencia en ciencias atmosféricas. Gestiona cuatro observatorios en Tenerife, incluido el Observatorio de Izaña de gran altitud, inaugurado en 1916 y que desde entonces ha realizado observaciones meteorológicas y climatológicas ininterrumpidas y se ha convertido en una estación centenaria de la OMM. Estos informes resumen las múltiples actividades llevadas a cabo por el Centro de Investigación Atmosférica de Izaña. El liderazgo del Centro en materia de investigación y desarrollo con respecto a las técnicas de medición, calibración y validación de última generación, así como la cooperación internacional, le han otorgado una reputación sobresaliente en lo que se refiere al tiempo, el clima, la hidrología y otros temas ambientales afines

    Izaña Atmospheric Research Center. Activity Report 2015-2016

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    This report is a summary of the many activities at the Izaña Atmospheric Research Center to the broader community. The combination of operational activities, research and development in state-of-the-art measurement techniques, calibration and validation and international cooperation encompass the vision of WMO to provide world leadership in expertise and international cooperation in weather, climate, hydrology and related environmental issues
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