ASCA Temperature Maps of Three Clusters of Galaxies Abell 1060, AWM7, and the Centaurus Cluster

We present two-dimensional temperature maps of three bright clusters of galaxies Abell 1060, AWM7, and the Centaurus cluster, based on multi-pointing observations with the ASCA GIS. The temperatures are derived from hardness ratios by taking into account the XRT response. For the Centaurus cluster, we subtracted the central cool component using the previous ASCA and ROSAT results, and the metallicity gradients observed in AWM7 and the Centaurus cluster were included in deriving the temperatures. The intracluster medium in Abell 1060 and AWM7 is almost isothermal from the center to outer regions with a temperature of 3.3 and 3.9 keV, respectively. The Centaurus cluster exhibits remarkable hot regions within about 30' from the cluster center showing a temperature increase of +0.8 keV from the surrounding level of 3.5 keV, and outer cool regions with lower temperatures by -1.3 keV. These results imply that a strong merger has occurred in the Centaurus in the recent 2-3 Gyr, and the central cool component has survived it. In contrast, the gas in Abell 1060 was well-mixed in an early period, which probably has prevented the development of the central cool component. In AWM7, mixing of the gas should have occurred in a period earlier than the epoch of metal enrichment.Comment: 18 pages, 8 figures (including color), Latex(PASJadd.sty, PASJ95.sty), accepted for publication in PASJ. Postscript is also available at http://www-x.phys.metro-u.ac.jp/~furusho/papers.htm

Diagnóstico da conservação das tartarugas marinhas em ambiente escolar

Mestrado em Biologia Aplicada - Ecologia, Biodiversidade e Gestão de EcossistemasDevido à exploração dos recursos naturais pelo homem, espécies de animais e plantas sofrem a ameaça de extinção. O impacto humano sobre os habitats das tartarugas marinhas é reconhecido há décadas, sendo que todas as espécies estão catalogadas como “vulneráveis” ou “em perigo”. Uma das formas de sensibilizar a sociedade sobre a sua importância e riscos é através da informação sobre essas questões. A Educação Ambiental surgiu na década de 60 e na Conferência de Estocolmo foi apontada como uma das estratégias para a solução dos problemas ambientais e para a educação dos indivíduos. Para que a educação seja efetiva, é necessário que o professor relacione os conteúdos aprendidos com o cotidiano dos alunos, para que os mesmos pensem as suas atitudes junto aos problemas ambientais. Este trabalho tem por objetivo identificar e caracterizar através da utilização de inquéritos, a percepção dos alunos de duas escolas em Aveiro, quanto aos conceitos ambientais focando a Conservação das Tartarugas Marinhas. Com base no levantamento da percepção dos alunos, foi possível identificar a necessidade de sensibilizá-los sobre as questões ambientais, principalmente na conservação de animais marinhos, pois a maioria não possui conhecimento da importância de sua preservação. Os inquéritos aplicados foram considerados uma boa ferramenta na avaliação para diagnosticar a percepção ambiental dos alunos. Resultados obtidos no inquérito experimental mostram que em relação ao conhecimento sobre o meio ambiente alunos do 1º Ciclo obtivem um maior conhecimento sobre o assunto do que alunos do 3º Ciclo (inquérito inicial e final), entretanto no inquérito de controle alunos do 1º e 3º Ciclos obtiveram o mesmo nível de conhecimento sobre o mesmo tema. Em relação ao conhecimento sobre a biologia das tartarugas marinhas alunos do 1º e 3º Ciclos tanto no inquéritos experimetal e controle obtiveram o mesmo nível de conhecimento no inquérito inicial e um aumento significativo no inquérito final.Due to mankind’s exploitation of natural resources, animal and plant species face the threat of extinction. Human impact on sea turtle’s natural habitats has been acknowledged for decades, with all species listed as "vulnerable" or "endangered". A way to make society aware of the importance and the risks is through the spread of information on these issues. Environmental education emerged in the 60’s, and in the “Stockholm Conference”, it was named one of the strategies for solving environmental problems and to educate people. For education to be effective, it is imperative that teachers relate the content learned in the classroom to the students’ daily lives so that they can apply what they learn to real environmental issues. This research aims to identify and illustrate the awareness of students through the use of surveys, with a focus on environmental concepts regarding the Conservation of Sea Turtle from two schools in Aveiro. Based on the survey results on the students’ awareness, it was possible to identify the need to familiarize them on environmental issues, especially in the conservation of sea animals, as most student do not have knowledge of the importance of its preservation. The surveys used were considered a good tool in the assessment to diagnose students' environmental awareness. Results obtained in the survey experiment show that concerning the knowledge about the environment, students from the 1st cycle got a better understanding of the subject than students in the 3rd cycle (the original and final). However, in the survey control students of the 1st and 3rd cycles achieved the same level of knowledge on the same topic. Concerning the knowledge about the biology of sea turtles, students from the 1st and 3rd cycles in both surveys (experimental and control surveys) achieved the same level of knowledge in the original survey and a significant increase in the final survey

X-Ray View of the Shock Front in the Merging Cluster Abell 3376 with Suzaku

We report on a Suzaku measurement of the shock feature associated with the western radio relic in the merging cluster A3376. The temperature profile is characterized by an almost flat radial shape with kT ~ 4 keV within 0.5 r200 and a rise by about 1 keV inside the radio relic. Across the relic region (0.6-0.8 r200), the temperature shows a remarkable drop from about 4.7 keV to 1.3 keV. This is a clear evidence that the radio relic really corresponds to a shock front possibly caused by a past major merger. The observed sharp changes of the temperature and electron density indicate the Mach number M~3. The radial entropy profile is flatter than the prediction (r^1.1) of numerical simulations within 0.5 r200}, and becomes steeper around the relic region. These observed features and time-scale estimation consistently imply that the ICM around the radio relic has experienced a merger shock and is in the middle of the process of dynamical and thermal relaxation.Comment: Accepted for publication in PASJ (12 pages, 6 figures

Suzaku X-Ray Observations of the Accreting NGC 4839 Group of Galaxies and the Radio Relic in the Coma Cluster

Based on Suzaku X-ray observations, we study the hot gas around the NGC4839 group of galaxies and the radio relic in the outskirts of the Coma cluster. We find a gradual decline in the gas temperature from 5 keV around NGC4839 to 3.6 keV at the radio relic, across which there is a further, steeper drop down to 1.5 keV. This drop as well as the observed surface brightness profile are consistent with a shock with Mach number M = 2.2 pm 0.5 and velocity vs = (1410 pm 110) km s^-1. A lower limit of B > 0.33 mu G is derived on the magnetic field strength around the relic from upper limits to inverse Compton X-ray emission. Although this suggests that the non-thermal electrons responsible for the relic are generated by diffusive shock acceleration (DSA), the relation between the measured Mach number and the electron spectrum inferred from radio observations are inconsistent with that expected from the simplest, test-particle theory of DSA. Nevertheless, DSA is still viable if it is initiated by the injection of a pre-existing population of non-thermal electrons. Combined with previous measurements, the temperature profile of Coma in the southwest direction is shallower outside NGC4839 and also slightly shallower in the outermost region. The metal abundance around NGC4839 is confirmed to be higher than in its vicinity, implying a significant peak in the abundance profile that decreases to 0.2 solar toward the outskirts. We interpret these facts as due to ram pressure stripping of metal-enriched gas from NGC4839 as it falls into Coma. The relic shock may result from the combined interaction of pre-existing intracluster gas, gas associated with NGC 4839, and cooler gas flowing in from the large-scale structure filament in the southwest.Comment: 13 page, accepted for publication in Publications of the Astronomical Society of Japa

Spectral Statistics and Luminosity Function of a Hard X-ray Complete Sample of Brightest AGNs

We investigated the statistics of the X-ray spectral properties of a complete flux-limited sample of bright AGNs from HEAO-1 all-sky catalogs to provide the bright end constraint of the evolution of AGN hard X-ray luminosity function (HXLF) and the AGN population synthesis model of the X-ray background. Spectral studies have been made using ASCA and XMM-Newton observation data for almost all AGNs in this sample.Comment: PTPTex v0.88, 2 pages with 4 figures, Proceedings of the "Stellar-Mass, Intermediate -Masss, and Supermassive Black Holes" in Kyoto, Japa

X-Ray Study of the Outer Region of Abell 2142 with Suzaku

We observed outer regions of a bright cluster of galaxies A2142 with Suzaku. Temperature and brightness structures were measured out to the virial radius ($r_{200}$) with good sensitivity. We confirmed the temperature drop from 9 keV around the cluster center to about 3.5 keV at $r_{200}$, with the density profile well approximated by the $\beta$ model with $\beta = 0.85$. Within 0.4\r_{200}, the entropy profile agrees with $r^{1.1}$, as predicted by the accretion shock model. The entropy slope becomes flatter in the outer region and negative around $r_{200}$. These features suggest that the intracluster medium in the outer region is out of thermal equilibrium. Since the relaxation timescale of electron-ion Coulomb collision is expected to be longer than the elapsed time after shock heating at $r_{200}$, one plausible reason of the low entropy is the low electron temperature compared to that of ions. Other possible explanations would be gas clumpiness, turbulence and bulk motions of ICM\@. We also searched for a warm-hot intergalactic medium around $r_{200}$ and set an upper limit on the oxygen line intensity. Assuming a line-of-sight depth of 2 Mpc and oxygen abundance of 0.1 solar, the upper limit of an overdensity is calculated to be 280 or 380, depending on the foreground assumption.Comment: 14 pages, 8 figure

Metallicity of the Fossil Group NGC 1550 Observed with Suzaku

We studied the temperature and metal abundance distributions of the intra-cluster medium (ICM) in a group of galaxies NGC 1550 observed with Suzaku. The NGC 1550 is classified as a fossil group, which have few bright member galaxies except for the central galaxy. Thus, such a type of galaxy is important to investigate how the metals are enriched to the ICM. With the Suzaku XIS instruments, we directly measured not only Si, S, and Fe lines but also O and Mg lines and obtained those abundances to an outer region of ~0.5 r_180 for the first time, and confirmed that the metals in the ICM of such a fossil group are indeed extending to a large radius. We found steeper gradients for Mg, Si, S, and Fe abundances, while O showed almost flat abundance distribution. Abundance ratios of alpha-elements to Fe were similar to those of the other groups and poor clusters. We calculated the number ratio of type II to type Ia supernovae for the ICM enrichment to be 2.9 +- 0.5 within 0.1 r_180, and the value was consistent with those for the other groups and poor clusters observed with Suzaku. We also calculated metal mass-to-light ratios (MLRs) for Fe, O and Mg with B-band and K-band luminosities of the member galaxies of NGC 1550. The derived MLRs were comparable to those of NGC 5044 group in the r<0.1 r_180 region, while those of NGC 1550 are slightly higher than those of NGC 5044 in the outer region.Comment: 11 pages, 7 figures, accepted for publication in PAS