In this paper we review the modeling of the Local Bubble (LB) with special emphasis on the progress we have made since the last major conference “The Local Bubble and Beyond (I)” held in Garching in 1997. Since then new insight was gained into the possible origin of the LB, with a moving group crossing its volume during the last 10–15 Myr being most likely responsible for creating a local cavity filled with hot recombining gas. Numerical high resolution 3D simulations of a supernova driven inhomogeneous interstellar medium show that we can reproduce both the extension of the LB and the OVI column density in absorption measured with FUSE for a LB age of 13.5–14.5 Myr. We further demonstrate that the LB evolves like an ordinary superbubble expanding into a density stratified medium by comparing analytical 2D Kompaneets solutions to NaI contours, representing the extension of the local cavity. These results suggest that LB blow‐out into the Milky Way halo has occurred roughly 5 Myr ago.
{"title":"Modeling the Local Warm/Hot Bubble","authors":"D. Breitschwerdt, M. Avillez, V. Baumgartner","doi":"10.1063/1.3211826","DOIUrl":"https://doi.org/10.1063/1.3211826","url":null,"abstract":"In this paper we review the modeling of the Local Bubble (LB) with special emphasis on the progress we have made since the last major conference “The Local Bubble and Beyond (I)” held in Garching in 1997. Since then new insight was gained into the possible origin of the LB, with a moving group crossing its volume during the last 10–15 Myr being most likely responsible for creating a local cavity filled with hot recombining gas. Numerical high resolution 3D simulations of a supernova driven inhomogeneous interstellar medium show that we can reproduce both the extension of the LB and the OVI column density in absorption measured with FUSE for a LB age of 13.5–14.5 Myr. We further demonstrate that the LB evolves like an ordinary superbubble expanding into a density stratified medium by comparing analytical 2D Kompaneets solutions to NaI contours, representing the extension of the local cavity. These results suggest that LB blow‐out into the Milky Way halo has occurred roughly 5 Myr ago.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83236813","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}
Simulations predict that shocks from large-scale structure formation and galactic winds have reduced the fraction of baryons in the warm, photoionized phase (the Lya forest) from nearly 100% in the early universe to less than 50% today. Some of the remaining baryons are predicted to lie in the warm-hot ionized medium (WHIM) phase at T=10^5-10^7 K, but the quantity remains a highly tunable parameter of the models. Modern UV spectrographs have provided unprecedented access to both the Lya forest and potential WHIM tracers at z~0, and several independent groups have constructed large catalogs of far-UV IGM absorbers along ~30 AGN sight lines. There is general agreement between the surveys that the warm, photoionized phase makes up ~30% of the baryon budget at z~0. Another ~10% can be accounted for in collapsed structures (stars, galaxies, etc.). However, interpretation of the ~100 high-ion (OVI, etc) absorbers at z<0.5 is more controversial. These species are readily created in the shocks expected to exist in the IGM, but they can also be created by photoionization and thus not represent WHIM material. Given several pieces of observational evidence and theoretical expectations, I argue that most of the observed OVI absorbers represent shocked gas at T~300,000 K rather than photoionized gas at T<30,000 K, and they are consequently valid tracers of the WHIM phase. Under this assumption, enriched gas at T=10^5-10^6 K can account for ~10% of the baryon budget at z<0.5, but this value may increase when bias and incompleteness are taken into account and help close the gap on the 50% of the baryons still "missing".
{"title":"Intergalactic Baryons in the Local Universe","authors":"C. Danforth","doi":"10.1063/1.3154092","DOIUrl":"https://doi.org/10.1063/1.3154092","url":null,"abstract":"Simulations predict that shocks from large-scale structure formation and galactic winds have reduced the fraction of baryons in the warm, photoionized phase (the Lya forest) from nearly 100% in the early universe to less than 50% today. Some of the remaining baryons are predicted to lie in the warm-hot ionized medium (WHIM) phase at T=10^5-10^7 K, but the quantity remains a highly tunable parameter of the models. Modern UV spectrographs have provided unprecedented access to both the Lya forest and potential WHIM tracers at z~0, and several independent groups have constructed large catalogs of far-UV IGM absorbers along ~30 AGN sight lines. There is general agreement between the surveys that the warm, photoionized phase makes up ~30% of the baryon budget at z~0. Another ~10% can be accounted for in collapsed structures (stars, galaxies, etc.). However, interpretation of the ~100 high-ion (OVI, etc) absorbers at z<0.5 is more controversial. These species are readily created in the shocks expected to exist in the IGM, but they can also be created by photoionization and thus not represent WHIM material. Given several pieces of observational evidence and theoretical expectations, I argue that most of the observed OVI absorbers represent shocked gas at T~300,000 K rather than photoionized gas at T<30,000 K, and they are consequently valid tracers of the WHIM phase. Under this assumption, enriched gas at T=10^5-10^6 K can account for ~10% of the baryon budget at z<0.5, but this value may increase when bias and incompleteness are taken into account and help close the gap on the 50% of the baryons still \"missing\".","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80964011","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}
A bright feature 100 pc away from the core in the powerful jet of M 87 shows mysterious properties. Earlier radio, optical and X-ray observations have shown that this feature, labelled HST-1, is superluminal, and is possibly connected with the TeV flare detected by HESS in 2005. To examine the possible blazar-like nature of HST-1, we analyzed 2 cm VLBA data from dedicated full-track observations and the 2 cm survey/MOJAVE VLBI monitoring programs observed from 2000 to 2008. Applying wide-field imaging techniques, the HST-1 region was imaged at milliarcsecond resolutions. Here we present the first 15 GHz VLBI detection of this feature and discuss the connection between our radio findings and the TeV detection.
{"title":"15 GHz VLBI detection of the HST-1 feature in the M87 jet","authors":"C. Chang, E. Ros, Y. Kovalev, M. Lister","doi":"10.22323/1.072.0010","DOIUrl":"https://doi.org/10.22323/1.072.0010","url":null,"abstract":"A bright feature 100 pc away from the core in the powerful jet of M 87 shows mysterious properties. Earlier radio, optical and X-ray observations have shown that this feature, labelled HST-1, is superluminal, and is possibly connected with the TeV flare detected by HESS in 2005. To examine the possible blazar-like nature of HST-1, we analyzed 2 cm VLBA data from dedicated full-track observations and the 2 cm survey/MOJAVE VLBI monitoring programs observed from 2000 to 2008. Applying wide-field imaging techniques, the HST-1 region was imaged at milliarcsecond resolutions. Here we present the first 15 GHz VLBI detection of this feature and discuss the connection between our radio findings and the TeV detection.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83351406","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}
Pub Date : 2008-11-29DOI: 10.1007/978-3-642-11250-8_5
E. Khomenko
{"title":"Magnetic Fingerprints of Solar and Stellar Oscillations","authors":"E. Khomenko","doi":"10.1007/978-3-642-11250-8_5","DOIUrl":"https://doi.org/10.1007/978-3-642-11250-8_5","url":null,"abstract":"","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88841629","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}
Pub Date : 2008-11-29DOI: 10.1051/0004-6361:200810125
A. Marco, I. Negueruela
(Abridged) The very luminous blue supergiant HD 80077 has been claimed to be a member of the young open cluster Pismis 11, and hence a hypergiant. We obtained UBVRI photometry of the cluster field and low-resolution spectroscopy of a number of putative members. We derive spectral types from the spectra and determine that the reddening in this direction is standard. We then carry out a careful photometric analysis that allows us to determine individual reddening values, deriving unreddened parameters that are used for the main sequence fit. We identify 43 likely members of Pismis 11. We study the variation of extinction across the face of the cluster and find some dispersion, with a trend to higher values in the immediate neighbourhood of HD 80077. We estimate a distance of 3.6 kpc for the cluster. If HD 80077 is a member, it has M_bol<-10.5 and it is one of the three visually brightest stars in the Galaxy. Several early type stars in the vicinity of Pismis~11 fit well the cluster sequence and are likely to represent an extended population at the same distance. About 18 arcmin to the North of Pismis 11, we find a small concentration of stars, which form a clear sequence. We identify this group as a previously uncatalogued open cluster, which we provisionally call Alicante 5. The distance to Alicante 5 is also 3.6 kpc, suggesting that these two clusters and neighbouring early-type stars form a small association. Based on its proper motion, HD 80077 is not a runaway star and may be a member of the cluster. If this is the case, it would be one of the brightest stars in the Galaxy.
{"title":"The open cluster Pismis 11 and the very luminous blue supergiant HD 80077","authors":"A. Marco, I. Negueruela","doi":"10.1051/0004-6361:200810125","DOIUrl":"https://doi.org/10.1051/0004-6361:200810125","url":null,"abstract":"(Abridged) The very luminous blue supergiant HD 80077 has been claimed to be a member of the young open cluster Pismis 11, and hence a hypergiant. We obtained UBVRI photometry of the cluster field and low-resolution spectroscopy of a number of putative members. We derive spectral types from the spectra and determine that the reddening in this direction is standard. We then carry out a careful photometric analysis that allows us to determine individual reddening values, deriving unreddened parameters that are used for the main sequence fit. We identify 43 likely members of Pismis 11. We study the variation of extinction across the face of the cluster and find some dispersion, with a trend to higher values in the immediate neighbourhood of HD 80077. We estimate a distance of 3.6 kpc for the cluster. If HD 80077 is a member, it has M_bol<-10.5 and it is one of the three visually brightest stars in the Galaxy. Several early type stars in the vicinity of Pismis~11 fit well the cluster sequence and are likely to represent an extended population at the same distance. About 18 arcmin to the North of Pismis 11, we find a small concentration of stars, which form a clear sequence. We identify this group as a previously uncatalogued open cluster, which we provisionally call Alicante 5. The distance to Alicante 5 is also 3.6 kpc, suggesting that these two clusters and neighbouring early-type stars form a small association. Based on its proper motion, HD 80077 is not a runaway star and may be a member of the cluster. If this is the case, it would be one of the brightest stars in the Galaxy.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80644333","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}
P. Young, C. Ellinger, F. Timmes, D. Arnett, C. Fryer, G. Rockefeller, A. Hungerford, S. Diehl, M. Bennett, R. Hirschi, M. Pignatari, F. Herwig, Georgios Magkotsios The NuGrid Collaboration, Los Alamos National Laboratory, A. S. University, Keele University, U. Victoria, U. N. Dame, U. Arizona
We examine observed heavy element abundances in the Cassiopeia A supernova remnant as a constraint on the nature of the Cas A supernova. We compare bulk abundances from 1D and 3D explosion models and spatial distribution of elements in 3D models with those derived from X-ray observations. We also examine the cospatial production of 26Al with other species. We find that the most reliable indicator of the presence of 26Al in unmixed ejecta is a very low S/Si ratio (~0.05). Production of N in O/S/Si-rich regions is also indicative. The biologically important element P is produced at its highest abundance in the same regions. Proxies should be detectable in supernova ejecta with high spatial resolution multiwavelength observations.
{"title":"Spatial Distribution of Nucleosynthesis Products in Cassiopeia A: Comparison Between Observations and 3D Explosion Models","authors":"P. Young, C. Ellinger, F. Timmes, D. Arnett, C. Fryer, G. Rockefeller, A. Hungerford, S. Diehl, M. Bennett, R. Hirschi, M. Pignatari, F. Herwig, Georgios Magkotsios The NuGrid Collaboration, Los Alamos National Laboratory, A. S. University, Keele University, U. Victoria, U. N. Dame, U. Arizona","doi":"10.22323/1.053.0020","DOIUrl":"https://doi.org/10.22323/1.053.0020","url":null,"abstract":"We examine observed heavy element abundances in the Cassiopeia A supernova remnant as a constraint on the nature of the Cas A supernova. We compare bulk abundances from 1D and 3D explosion models and spatial distribution of elements in 3D models with those derived from X-ray observations. We also examine the cospatial production of 26Al with other species. We find that the most reliable indicator of the presence of 26Al in unmixed ejecta is a very low S/Si ratio (~0.05). Production of N in O/S/Si-rich regions is also indicative. The biologically important element P is produced at its highest abundance in the same regions. Proxies should be detectable in supernova ejecta with high spatial resolution multiwavelength observations.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77002296","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}
F. Herwig, M. Bennett, S. Diehl, C. Fryer, R. Hirschi, A. Hungerford, G. Magkotsios, M. Pignatari, G. Rockefeller, F. Timmes, Patrick Young The NuGrid Collaboration, Los Alamos National Laboratory, A. S. University, Keele University, U. Victoria, U. N. Dame
Simulations of nucleosynthesis in astrophysical environments are at the intersection of nuclear physics reaction rate research and astrophysical applications, for example in the area of galactic chemical evolution or near-field cosmology. Unfortunately, at present the available yields for such applications are based on heterogeneous assumptions between the various contributing nuclear production sites, both in terms of modeling the thermodynamic environment itself as well as the choice of specifc nuclear reaction rates and compilations. On the other side, new nuclear reaction rate determinations are often taking a long time to be included in astrophysical applications. The NuGrid project addresses these issues by providing a set of codes and a framework in which these codes interact. In this contribution we describe the motivation, goals and first results of the NuGrid project. At the core is a new and evolving post-processing nuclesoynthesis code (PPN) that can follow quiescent and explosive nucleosynthesis following multi-zone 1D-stellar evolution as well as multi-zone hydrodynamic input, including explosions. First results are available in the areas of AGB and massive stars.
{"title":"Nucleosynthesis simulations for a wide range of nuclear production sites from NuGrid","authors":"F. Herwig, M. Bennett, S. Diehl, C. Fryer, R. Hirschi, A. Hungerford, G. Magkotsios, M. Pignatari, G. Rockefeller, F. Timmes, Patrick Young The NuGrid Collaboration, Los Alamos National Laboratory, A. S. University, Keele University, U. Victoria, U. N. Dame","doi":"10.22323/1.053.0023","DOIUrl":"https://doi.org/10.22323/1.053.0023","url":null,"abstract":"Simulations of nucleosynthesis in astrophysical environments are at the intersection of nuclear physics reaction rate research and astrophysical applications, for example in the area of galactic chemical evolution or near-field cosmology. Unfortunately, at present the available yields for such applications are based on heterogeneous assumptions between the various contributing nuclear production sites, both in terms of modeling the thermodynamic environment itself as well as the choice of specifc nuclear reaction rates and compilations. On the other side, new nuclear reaction rate determinations are often taking a long time to be included in astrophysical applications. The NuGrid project addresses these issues by providing a set of codes and a framework in which these codes interact. In this contribution we describe the motivation, goals and first results of the NuGrid project. At the core is a new and evolving post-processing nuclesoynthesis code (PPN) that can follow quiescent and explosive nucleosynthesis following multi-zone 1D-stellar evolution as well as multi-zone hydrodynamic input, including explosions. First results are available in the areas of AGB and massive stars.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76120679","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}
The year 2008 has witnessed remarkable steps in developing high energy neutrino telescopes. IceCube at the South Pole has been deployed with 40 of its planned 80 strings and reached half a cubic kilometer instrumented volume, in the Mediterranean Sea the “first‐stage” neutrino telescope ANTARES has been completed and takes data with 12 strings. The next years will be key years for opening the neutrino window to the high energy universe. IceCube is presently entering a region with realistic discovery potential. Early discoveries (or non‐discoveries) with IceCube will strongly influence the design and the estimated discovery chances of the Northern equivalent KM3NeT. Following theoretical estimates, cubic kilometer telescopes may just scratch the regions of discovery. Therefore detectors presently planned should reach sensitivities substantially beyond those of IceCube.
{"title":"High Energy Neutrino Astronomy: Status and Perspectives","authors":"C. Spiering","doi":"10.1063/1.3076635","DOIUrl":"https://doi.org/10.1063/1.3076635","url":null,"abstract":"The year 2008 has witnessed remarkable steps in developing high energy neutrino telescopes. IceCube at the South Pole has been deployed with 40 of its planned 80 strings and reached half a cubic kilometer instrumented volume, in the Mediterranean Sea the “first‐stage” neutrino telescope ANTARES has been completed and takes data with 12 strings. The next years will be key years for opening the neutrino window to the high energy universe. IceCube is presently entering a region with realistic discovery potential. Early discoveries (or non‐discoveries) with IceCube will strongly influence the design and the estimated discovery chances of the Northern equivalent KM3NeT. Following theoretical estimates, cubic kilometer telescopes may just scratch the regions of discovery. Therefore detectors presently planned should reach sensitivities substantially beyond those of IceCube.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82267607","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}
MAGIC is a single‐dish Cherenkov telescope located on La Palma (Spain), hence with an optimal view on the Northern sky. Sensitive in the 30 GeV—30 TeV energy band, it is nowadays the only ground‐based instrument being able to measure high‐energy γ‐rays below 100 GeV. We review the most recent experimental results on Galactic sources obtained using MAGIC. These include pulsars, binary systems, supernova remnants and unidentified sources.
{"title":"Results of MAGIC on Galactic sources","authors":"J. Rico, F. C. Collaboration","doi":"10.1063/1.3076633","DOIUrl":"https://doi.org/10.1063/1.3076633","url":null,"abstract":"MAGIC is a single‐dish Cherenkov telescope located on La Palma (Spain), hence with an optimal view on the Northern sky. Sensitive in the 30 GeV—30 TeV energy band, it is nowadays the only ground‐based instrument being able to measure high‐energy γ‐rays below 100 GeV. We review the most recent experimental results on Galactic sources obtained using MAGIC. These include pulsars, binary systems, supernova remnants and unidentified sources.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74849601","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}
The CDMS-II experiment operates 19 germanium detectors with a mass of 250g each in a very low background environment. Originally designed for the search for Dark Matter the experiment can also detect solar axions by Primakoff conversion to photons. The Bragg condition for X-ray momentum transfer in a crystal allows for coherent amplification of the Primakoff process. Since the orientation of the crystal lattice with respect to the Sun changes with daytime an unique pattern in time and energy of solar axion conversions is expected. The low background ~1.5 counts/kg/day/keV and knowledge of the exact orientation of all three crystal axes with respect to the Sun make the CDMS-II experiment very sensitive to solar axions. In contrast to helioscopes, the high mass region < 1 keV can also be probed effectively. The alternating orientations of the individual crystals in the experimental setup provide different patterns of solar axion conversion, making a false positive result extremely unlikely. The result of an analysis of 289 kg-days of exposure resulted in a null observation of solar axion conversion. This analysis sets an upper limit on the axion photon coupling constant of g_{agammagamma} < 2.6 x 10^{-9} GeV{-1} at a 95% confidence level.
{"title":"Search for Solar Axions with the CDMS-II Experiment","authors":"T. Bruch, F. C. Collaboration","doi":"10.22323/1.064.0104","DOIUrl":"https://doi.org/10.22323/1.064.0104","url":null,"abstract":"The CDMS-II experiment operates 19 germanium detectors with a mass of 250g each in a very low background environment. Originally designed for the search for Dark Matter the experiment can also detect solar axions by Primakoff conversion to photons. The Bragg condition for X-ray momentum transfer in a crystal allows for coherent amplification of the Primakoff process. Since the orientation of the crystal lattice with respect to the Sun changes with daytime an unique pattern in time and energy of solar axion conversions is expected. The low background ~1.5 counts/kg/day/keV and knowledge of the exact orientation of all three crystal axes with respect to the Sun make the CDMS-II experiment very sensitive to solar axions. In contrast to helioscopes, the high mass region < 1 keV can also be probed effectively. The alternating orientations of the individual crystals in the experimental setup provide different patterns of solar axion conversion, making a false positive result extremely unlikely. The result of an analysis of 289 kg-days of exposure resulted in a null observation of solar axion conversion. This analysis sets an upper limit on the axion photon coupling constant of g_{agammagamma} < 2.6 x 10^{-9} GeV{-1} at a 95% confidence level.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82852034","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}
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