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Gamma ray emission and stochastic particle acceleration in galaxy clusters 星系团中的伽马射线发射和随机粒子加速
arXiv: Astrophysics Pub Date : 2008-11-06 DOI: 10.1063/1.3076753
G. Brunetti, P. Blasi, R. Cassano, S. Gabici
{"title":"Gamma ray emission and stochastic particle acceleration in galaxy clusters","authors":"G. Brunetti, P. Blasi, R. Cassano, S. Gabici","doi":"10.1063/1.3076753","DOIUrl":"https://doi.org/10.1063/1.3076753","url":null,"abstract":"FERMI (formely GLAST) will shortly provide crucial information on relativistic particles in galaxy clusters. We discuss non thermal emission in the context of general calculations in which relativistic particles (protons and secondary electrons due to proton‐proton collisions) interact with MHD turbulence generated in the cluster volume during cluster mergers. Diffuse cluster‐scale radio emission (Radio Halos) and hard X‐rays are produced during massive mergers while gamma ray emission, at some level, is expected to be common in galaxy clusters.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":"52 1","pages":"628-631"},"PeriodicalIF":0.0,"publicationDate":"2008-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72995170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
Sky-maps of the sidereal anisotropy of galactic cosmic ray intensity and its energy dependence 星系宇宙射线强度的各向异性及其能量依赖性的天空图
arXiv: Astrophysics Pub Date : 2008-11-04 DOI: 10.1142/9789812838209_0017
K. Munakata, N. Matsumoto, S. Yasue, C. Kato, S. Mori, M. Takita, M. Duldig, J. Humble, J. Kota
{"title":"Sky-maps of the sidereal anisotropy of galactic cosmic ray intensity and its energy dependence","authors":"K. Munakata, N. Matsumoto, S. Yasue, C. Kato, S. Mori, M. Takita, M. Duldig, J. Humble, J. Kota","doi":"10.1142/9789812838209_0017","DOIUrl":"https://doi.org/10.1142/9789812838209_0017","url":null,"abstract":"We analyze the sidereal daily variations observed between 1985 and 2006 at Matsushiro, Japan (MAT) and between 1993 and 2005 at Liapootah, Tasmania (LPT). These stations comprise the two hemisphere network (THN) of underground muon detectors in Japan and Australia. Yearly mean harmonic vectors at MAT and LPT are more or less stable without any significant change in phase and amplitude in correlation with either the solar activity- or magnetic-cycles. In this paper, therefore, we analyze the average anisotropy over the entire observation periods, i.e. 1985-2006 for MAT and 1993-2005 for LPT. We apply to the THN data a best-fitting analysis based on a model anisotropy in space identical to that adopted by Amenomori et al. (2007) for Tibet III data. The median energies of primary cosmic rays recorded are ~0.5 TeV for THN and ~5 TeV for the Tibet III experiment. It is shown that the intensity distribution of the best-fit anisotropy is quite similar to that derived from Tibet III data, regardless of the order of magnitude difference in energies of primary particles. This, together with the THN observations, confirms that the analysis by Amenomori et al. (2007) based on the Tibet III experiment in the northern hemisphere is not seriously biased. The best-fit amplitudes of the anisotropy, on the other hand, are only one third or less of those reported by the Tibet III experiment, indicating attenuation due to solar modulation. The rigidity dependence of the anisotropy amplitude in the sub-TeV region is consistent with the spectrum reported by Hall et al. (1999), smoothly extending to the Tibet III result in the multi-TeV region. The amplitude at higher energies appears almost constant or gradually decreasing with increasing rigidity.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2008-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80965549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Dynamical masses for the nearest brown dwarf binary: ε Indi Ba, Bb 最近的褐矮星双星的动力质量:ε Indi Ba, Bb
arXiv: Astrophysics Pub Date : 2008-11-04 DOI: 10.1063/1.3099160
C. Cardoso, M. McCaughrean, R. R. King, L. Close, R. Scholz, R. Lenzen, W. Brandner, N. Lodieu, H. Zinnecker
{"title":"Dynamical masses for the nearest brown dwarf binary: ε Indi Ba, Bb","authors":"C. Cardoso, M. McCaughrean, R. R. King, L. Close, R. Scholz, R. Lenzen, W. Brandner, N. Lodieu, H. Zinnecker","doi":"10.1063/1.3099160","DOIUrl":"https://doi.org/10.1063/1.3099160","url":null,"abstract":"We present preliminary astrometric results for the closest known brown dwarf binary to the Sun: e Indi Ba, Bb at a distance of 3.626 pc. With ongoing monitoring of the relative separation of the two brown dwarfs (spectral types T1 and T6) with VLT NACO near‐IR adaptive optics system since June 2004, we obtain a model‐independent dynamical total mass for the system of 121 MJup, some 60% larger than the one obtained by McCaughrean et al., implying that the system may be as old as 5 Gyr. We have also been monitoring the absolute astrometric motions of the system using the VLTFORS2 optical imager since August 2005 to determine the individual masses. We predict a periastron passage in early 2010, by which time the system mass will be constrained to <1 MJup and we will be able to determine the individual masses accurately in a dynamical, model‐independent manner.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":"45 1","pages":"509-512"},"PeriodicalIF":0.0,"publicationDate":"2008-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75571691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
The full spectrum Galactic terrarium: MHz to TeV observations of various critters 全光谱的银河玻璃容器:兆赫到TeV对各种生物的观察
arXiv: Astrophysics Pub Date : 2008-11-04 DOI: 10.1063/1.3076673
M. Roberts, C. L. Brogan, S. Ransom, M. Lyutikov, E. Wilhelmi, A. Djannati-Ataï, R. Terrier, S. Dougherty, E. Grundstrom, J. Hessels, Simon Johnston, M. McSwain, P. Ray, K. Wood, G. G. Pooley, A. Weinstein
{"title":"The full spectrum Galactic terrarium: MHz to TeV observations of various critters","authors":"M. Roberts, C. L. Brogan, S. Ransom, M. Lyutikov, E. Wilhelmi, A. Djannati-Ataï, R. Terrier, S. Dougherty, E. Grundstrom, J. Hessels, Simon Johnston, M. McSwain, P. Ray, K. Wood, G. G. Pooley, A. Weinstein","doi":"10.1063/1.3076673","DOIUrl":"https://doi.org/10.1063/1.3076673","url":null,"abstract":"Multi-wavelength studies at radio, infrared, optical, X-ray, and TeV wavelengths have discovered probable counterparts to many Galactic sources of GeV emission detected by EGRET. These include pulsar wind nebulae, high mass X-ray binaries, and mixed morphology supernova remnants. Here we provide an overview of the observational properties of Galactic sources which emit across 19 orders of magnitude in energy. We also present new observations of several sources.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":"153 1","pages":"328-331"},"PeriodicalIF":0.0,"publicationDate":"2008-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80995494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Parameter Estimation from an Optimal Projection in a Local Environment 局部环境下最优投影的参数估计
arXiv: Astrophysics Pub Date : 2008-11-03 DOI: 10.1063/1.3059083
A. Bijaoui, A. Recio-Blanco, P. Laverny
{"title":"Parameter Estimation from an Optimal Projection in a Local Environment","authors":"A. Bijaoui, A. Recio-Blanco, P. Laverny","doi":"10.1063/1.3059083","DOIUrl":"https://doi.org/10.1063/1.3059083","url":null,"abstract":"The parameter fit from a model grid is limited by our capability to reduce the number of models, taking into account the number of parameters and the non linear variation of the models with the parameters. The Local MultiLinear Regression (LMLR) algorithms allow one to fit linearly the data in a local environment. The MATISSE algorithm, developed in the context of the estimation of stellar parameters from the Gaia RVS spectra, is connected to this class of estimators. A two-steps procedure was introduced. A raw parameter estimation is first done in order to localize the parameter environment. The parameters are then estimated by projection on specific vectors computed for an optimal estimation. The MATISSE method is compared to the estimation using the objective analysis. In this framework, the kernel choice plays an important role. The environment needed for the parameter estimation can result from it. The determination of a first parameter set can be also avoided for this analysis. These procedures based on a local projection can be fruitfully applied to non linear parameter estimation if the number of data sets to be fitted is greater than the number of models.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2008-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79383226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Doppler maps and surface differential rotation of EI Eri from the MUSICOS 1998 observations 来自MUSICOS 1998观测的EI Eri的多普勒图和地表自转差异
arXiv: Astrophysics Pub Date : 2008-11-03 DOI: 10.1063/1.3099204
Zs. KHov'ari, A. Washuettl, B. Foing, K. Vida, J. Bartus, K. Ol'ah, the Musicos 98 team
{"title":"Doppler maps and surface differential rotation of EI Eri from the MUSICOS 1998 observations","authors":"Zs. KHov'ari, A. Washuettl, B. Foing, K. Vida, J. Bartus, K. Ol'ah, the Musicos 98 team","doi":"10.1063/1.3099204","DOIUrl":"https://doi.org/10.1063/1.3099204","url":null,"abstract":"We present time‐series Doppler images of the rapidly‐rotating active binary star EI Eri from spectroscopic observations collected during the MUSICOS multi‐site campaign in 1998, since the critical rotation period of 1.947 days makes it impossible to obtain time‐resolved images from a single site. From the surface reconstructions a weak solar‐type differential rotation, as well as a tiny poleward meridional flow are measured.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":"519 1","pages":"676-679"},"PeriodicalIF":0.0,"publicationDate":"2008-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77196930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Mass and Mean Velocity Dispersion Relations for Supermassive Black Holes in Galactic Bulges 星系凸起中超大质量黑洞的质量和平均速度色散关系
arXiv: Astrophysics Pub Date : 2008-11-03 DOI: 10.22323/1.062.0110
Y. Lou, Yan-Fei Jiang
{"title":"Mass and Mean Velocity Dispersion Relations for Supermassive Black Holes in Galactic Bulges","authors":"Y. Lou, Yan-Fei Jiang","doi":"10.22323/1.062.0110","DOIUrl":"https://doi.org/10.22323/1.062.0110","url":null,"abstract":"Growing evidence indicate supermassive black holes (SMBHs) in the mass range of $M_{rm BH}$$sim 10^6-10^{10}M_{odot}$ lurking in central bulges of many galaxies. Extensive observations reveal fairly tight power laws of $M_{rm BH}$ versus the mean stellar velocity dispersion $sigma$ of the host bulge. The dynamic evolution of a bulge and the formation of a central SMBH should be physically linked by various observational clues. In this contribution, we reproduce the empirical $M_{rm BH}-sigma$ power laws based on a self-similar general polytropic quasi-static bulge evolution and a sensible criterion of forming a SMBH surrounding the central density singularity of a general singular polytropic sphere (SPS) cite{loujiang2008}. Other properties of host bulges and central SMBHs are also examined. Based on our model, we discuss the intrinsic scatter of the $M_{rm BH}-sigma$ relation and a scenario for the evolution of SMBHs in different host bulges.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2008-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83613667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Science with the World Space Observatory - Ultraviolet 科学与世界空间天文台-紫外线
arXiv: Astrophysics Pub Date : 2008-11-03 DOI: 10.1007/978-0-387-87621-4_42
A. Castro, I. Pagano, M. Sachkov, A. Lecavelier, G. Piotto, R. González, B. Shustov
{"title":"Science with the World Space Observatory - Ultraviolet","authors":"A. Castro, I. Pagano, M. Sachkov, A. Lecavelier, G. Piotto, R. González, B. Shustov","doi":"10.1007/978-0-387-87621-4_42","DOIUrl":"https://doi.org/10.1007/978-0-387-87621-4_42","url":null,"abstract":"","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2008-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85969574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 33
Massive star formation in Wolf-Rayet galaxies: I. Optical and NIR photometric results Wolf-Rayet星系中大质量恒星的形成:1 .光学和近红外光度测量结果
arXiv: Astrophysics Pub Date : 2008-11-01 DOI: 10.1051/0004-6361:200809409
Á. López-Sánchez, C. Esteban
{"title":"Massive star formation in Wolf-Rayet galaxies: I. Optical and NIR photometric results","authors":"Á. López-Sánchez, C. Esteban","doi":"10.1051/0004-6361:200809409","DOIUrl":"https://doi.org/10.1051/0004-6361:200809409","url":null,"abstract":"(Abridged) We have performed a comprehensive multiwavelength analysis of a sample of 20 starburst galaxies that show the presence of a substantial population of massive stars. The main aims are the study of the massive star formation and stellar populations in these galaxies, and the role that interactions with or between dwarf galaxies and/or low surface companion objects have in triggering the bursts. We completed new deep optical and NIR broad-band images, as well as the new continuum-subtracted H$alpha$ maps, of our sample of Wolf-Rayet galaxies. We analyze the morphology of each system and its surroundings and quantify the photometric properties of all important objects. All data were corrected for both extinction and nebular emission using our spectroscopic data. The age of the most recent star-formation burst is estimated and compared with the age of the underlying older low-luminosity population. The Ha-based star-formation rate, number of O7V equivalent stars, mass of ionized gas, and mass of the ionizing star cluster are also derived. We found interaction features in many (15 up to 20) of the analyzed objects, which were extremely evident in the majority. We checked that the correction for nebular emission to the broad-band filter fluxes is important in compact objects and/or with intense nebular emission to obtain realistic colors and compare with the predictions of evolutionary synthesis models. The estimate of the age of the most recent star-formation burst is derived consistently. With respect to the results found in individual objects, we remark the strong Ha emission found in IRAS 08208+2816, UM 420, and SBS 0948+532, the detection of a double-nucleus in SBS 0926+606A, a possible galactic wind in Tol 9, and one (two?) nearby dwarf star-forming galaxies surrounding Tol 1457-437.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":"99 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89918020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 40
Supergiant Fast X-ray Transients: interpretation of archival INTEGRAL data 超巨星快速x射线瞬变:档案积分数据的解释
arXiv: Astrophysics Pub Date : 2008-10-30 DOI: 10.22323/1.067.0086
L. Ducci, L. Sidoli, A. Paizis, S. M. U. D. S. dell'Insubria, Como INAF-IASF Milano, Italy.
{"title":"Supergiant Fast X-ray Transients: interpretation of archival INTEGRAL data","authors":"L. Ducci, L. Sidoli, A. Paizis, S. M. U. D. S. dell'Insubria, Como INAF-IASF Milano, Italy.","doi":"10.22323/1.067.0086","DOIUrl":"https://doi.org/10.22323/1.067.0086","url":null,"abstract":"INTEGRAL monitoring of the Galactic Plane in the last 5 years revealed a new subclass of High Mass X-ray Binaries (HMXBs), the Supergiant Fast X-ray Transients (SFXTs). They display flares lasting from minutes to hours, with peak luminosity of 1E36-1E37 erg/s and a frequent long term flaring activity reaching an X-ray luminosity of 1E33-1E34 erg/s, as recently detected by the Swift satellite. The quiescent level is around 1E32 erg/s. We performed a systematic re-analysis of archival INTEGRAL data of four SFXTs: IGRJ16479-4514, XTEJ1739-302, IGRJ17544-2619, IGRJ18410-0535. This led to the discovery of previously unnoticed outbursts from IGRJ16479-4514 and IGRJ17544-2619. We discuss these results in the framework of the different structure of the supergiant wind proposed to explain the outburst from this new class of sources.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2008-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89058902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
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