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1
Bush, Elizabeth. « Icecore : A Carl Hobbes Thriller (review) ». Bulletin of the Center for Children's Books 61, no 6 (2008) : 270. http://dx.doi.org/10.1353/bcc.2008.0068.
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Siggaard-Andersen, Marie-Louise, Jørgen Peder Steffensen et Hubertus Fischer. « Lithium in Greenland ice cores measured by ion chromatography ». Annals of Glaciology 35 (2002) : 243–49. http://dx.doi.org/10.3189/172756402781816483.
Texte intégralRésumé :
AbstractIon chromatography (IC) is a widely used technique for analyzing ice cores for ions like Na+, NH4+, K+, Mg2+, Ca2+, F–, MSA–, Cl–, NO2– and SO42– that are present in polar ice cores at ppb level. By using sample preconcentration and an optimized separation technique, we have been able to detect Li+ in ice-core samples in concentrations as low as 0.0001 μeq kg–1 or 0.7 ppt by IC. During routine analysis of ions in ice cores, the lithium content has been evaluated and recorded. the IC technique used in these measurements and some exemplary IC data from the Greenland Icecore Project (GRIP) and the North Greenland Icecore Project (NorthGRIP) ice cores are presented. By these data we introduce Li+ concentration as a new parameter in the analysis of ice cores. Like other ions, Li+ reflects climatic changes and shows seasonal cycles. on the basis of the geochemistry of lithium, we suggest that Li+ measured in the Greenland ice cores is derived from mineral dust. However, data from the NorthGRIP ice core representing the 8.2 kyr BPHolocene cold event show a strong Li+ signal that does not correlate with any other ionic component measured. This means that the lithium content in ice cores is a signal with its own pattern, which is not yet understood.
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Dahl-Jensen, Dorthe, Niels S. Gundestrup, Heinz Miller, Okitsugu Watanabe, Sigfús J. Johnsen, Jørgen P. Steffensen, Henrik B. Clausen, Anders Svensson et Lars B. Larsen. « The NorthGRIP deep drilling programme ». Annals of Glaciology 35 (2002) : 1–4. http://dx.doi.org/10.3189/172756402781817275.
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AbstractThe North Greenland Icecore Project (NorthGRIP) was initiated in 1995 as a joint international programme involving Denmark, Germany, Japan, Belgium, Sweden, Iceland, the U.S.A., France and Switzerland. the main goal was to obtain undisturbed high-resolution information about the Eemian climatic period (115–130 kyr BP). the records from the Greenland Icecore Project (GRIP) and Greenland Ice Sheet Project 2 (GISP2) in central Greenland are different and disturbed down in the ice covering this period. Internal radio-echo sounding layers show that NorthGRIP, placed 325 km north-northwest of GRIP at the Summit of the Greenland ice sheet, is located on a gently sloping ice ridge with very flat bedrock and internal layers found so high that an undisturbed Eemian record is possible. Internal layers much farther above bedrock than their apparent counter parts at GRIP suggest that conditions are favourable for recovery of an undisturbed Eemian record. So far, a 1351 mdeep ice core (NorthGRIP1) and a 3001 mdeep ice core (NorthGRIP 2) have been recovered. the ice thickness is expected to be 3080 m, and the ice temperature at 3001 m is –5.6°C, so we expect basal melting at the bedrock. Most of the Eemian ice will be melted away, leaving only the last part and the transition between the Eem and the Last Glacial Period. At 3001 m the age of the ice is 110 kyr BP and the annual layers are of the order 1 cm.With modern methods the annual layers can be resolved, resulting in detailed information on the decline of the warm Eemian period into the Last Glacial Period.
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Mathiesen, Joachim, Jesper Ferkinghoff-Borg, Mogens H. Jensen, Mogens Levinsen, Poul Olesen, Dorthe Dahl-Jensen et Anders Svensson. « Dynamics of crystal formation in the Greenland NorthGRIP ice core ». Journal of Glaciology 50, no 170 (2004) : 325–28. http://dx.doi.org/10.3189/172756504781829873.
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AbstractThe North Greenland Icecore Project (NorthGRIP) palaeoclimatic information back to about 120 kyr BP. The size distributions of ice crystals in the upper 880 m of the NorthGRIP ice core, which cover a time-span of approximately 5300 years, have been obtained previously. The distributions evolve towards a universal curve, indicating a common underlying physical process in the formation of crystals. We identify this process as an interplay between fragmentation of the crystals and diffusion of their grain boundaries. The process is described by a two-parameter differential equation to which we obtain the exact solution. The solution is in excellent agreement with the measured distributions.
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Thomas, Elizabeth R., Robert Mulvaney et Eric W. Wolff. « A change in seasonality in Greenland during a Dansgaard–Oeschger warming ». Annals of Glaciology 48 (2008) : 19–24. http://dx.doi.org/10.3189/172756408784700590.
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AbstractA new sub-seasonal chemical record is presented from the North Greenland Icecore Project (NorthGRIP) ice core during the onset of one of the longest and strongest interstadials of the last glacial period, Dansgaard–Oeschger event 8 (approximately 38 000 years ago). This is the first time that a record of such resolution has been achieved over several metres of deep glacial ice and provides a unique opportunity for using additional parameters to carry out accurate dating using annual-layer counting. The very high-resolution chemical data were used to assess the phasing of various ions and determine changes in the seasonal strength of chemical deposition and the shape of the seasonal cycle. The study shows that a change in seasonality accompanied the dramatic warming transition from stadial to interstadial conditions in Greenland.
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Hvidberg, Christine Schøtt, Kristian Keller et Niels S. Gundestrup. « Mass balance and ice flow along the north-northwest ridge of the Greenland ice sheet at NorthGRIP ». Annals of Glaciology 35 (2002) : 521–26. http://dx.doi.org/10.3189/172756402781816500.
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AbstractThe North Greenland Icecore Project (NorthGRIP) deep drilling site (75˚05’47’’N, 42˚19’42’’ W) is located at the north-northwest ridge of the Greenland ice sheet, 320 km from Summit. A strain net has been established around the NorthGRIP site and surveyed with global positioning system. Our results show that ice flows with a horizontal surface velocity of 1.329 ±0.015ma–1 along the ridge. Estimated principal surface strain rates at NorthGRIP are and in the directions along and transverse to the north-northwest ridge, respectively, i.e. ice is compressed along the ridge but stretched transverse to the ridge. Possible implications of the observed flow pattern for the stratigraphy are discussed. the average thickening rate in the strain-net area is found to be ∂H/∂t = 0.00 ±0.04ma– 1, in agreement with previous estimates of mass balance in high-elevation areas of Greenland.
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Svensson, Anders, Karen G. Schmidt, Dorthe Dahl-Jensen, Sigfús J. Johnsen, Yun Wang, Sepp Kipfstuhl et Thorsteinn Thorsteinsson. « Properties of ice crystals in NorthGRIP late- to middle-Holocene ice ». Annals of Glaciology 37 (2003) : 113–18. http://dx.doi.org/10.3189/172756403781815636.
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AbstractDetailed measurements of crystal outlines and fabrics have been performed on 35 000 crystals in fifteen 10 × 20 cm2 vertical thin sections from the North Greenland Icecore Project (NorthGRIP) ice core, evenly distributed in the depth interval 115–880m. The crystals exhibit important changes over this period. As the ice gets older the mean crystal area increases towards a constant value, the shape of the crystals becomes increasingly irregular, and the area distribution of crystals develops from a single log-normal distribution into a bimodal lognormal distribution. The c-axis fabric of the ice shows a smooth development of an increasingly stronger vertical fabric with depth, and the formation of a weak vertical girdle. Already in the younger samples the fabric is rather strongly oriented towards vertical. The fabric and the area of individual crystals are found not to correlate. A simple model, which takes into account the vertical strain of the ice, is applied in an attempt to determine the crystal growth rate at NorthGRIP.
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Hvidberg, Christine Schøtt, Jørgen Peder Steffensen, Henrik B. Clausen, Hitoshi Shoji et Joseph Kipfstuhl. « The NorthGRIP ice-core logging procedure : description and evaluation ». Annals of Glaciology 35 (2002) : 5–8. http://dx.doi.org/10.3189/172756402781817293.
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AbstractThe ice-core logging procedure used to log the North Greenland Icecore Project (NorthGRIP) ice cores is described. the existence of two deep ice cores, NorthGRIP 1and 2, drilled 25 mapart, allows an independent evaluation of the procedure. the logged depths of the NorthGRIP 1 and 2 cores deviate from the length of the unwound drill cable corrected for elongation of the cable when hanging in the hole, by 1.5‰ and 50.5‰ at depths of 1371 and 2931 m, respectively. Differences between logged depths of identified layers found in both cores are studied in the depth interval where they overlap. Layers are identified by electrical conductivity measurements and dielectric profiling. the difference between the logged depths of layers identified in both cores increases to 0.5 m close to the bottom of the NorthGRIP 1 core, which is <0.5 mm m–1 ice core. the comparison between the two cores shows that the NorthGRIP logging procedure is accurate and reproducible. Further, our results show that the temperature conditions and handling of the core during logging are important for obtaining a precise depth.
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Dahl-Jensen, Dorthe, Niels Gundestrup, S. Prasad Gogineni et Heinz Miller. « Basal melt at NorthGRIP modeled from borehole, ice-core and radio-echo sounder observations ». Annals of Glaciology 37 (2003) : 207–12. http://dx.doi.org/10.3189/172756403781815492.
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AbstractFrom temperature measurements down through the 3001 m deep borehole at the North Greenland Icecore Project (NorthGRIP) drill site, it is now clear that the ice at the base, 3080 m below the surface, is at the pressure-melting point. This is supported by the measurements on the ice core where the annual-layer thicknesses show there is bottom melting at the site and upstream from the borehole. Surface velocity measurements, internal radio-echo layers, borehole and ice-core data are used to constrain a time-dependent flow model simulating flow along the north-northwest-trending ice-ridge flow-line, leading to the NorthGRIP site. Also time-dependent melt rates along the flowline are calculated with a heat-flow model. The results show the geothermal heat flow varies from 50 to 200 mW m–2 along the 100km section of the modeled flowline. The melt rate at the NorthGRIP site is 0.75 cm a–1, but the deep ice in the NorthGRIP core originated 50 km upstream and has experienced melt rates as high as 1.1 cm a–1.
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Svensson, Anders, Pauli Baadsager, Asbjørn Persson, Christine Schøtt Hvidberg et Marie-Louise Siggaard-Andersen. « Seasonal variability in ice crystal properties at NorthGRIP : a case study around 301 m depth ». Annals of Glaciology 37 (2003) : 119–22. http://dx.doi.org/10.3189/172756403781815582.
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AbstractThe aim of this case study is to quantify the seasonal variability in crystal properties and to discuss the reason for the variability. A continuous 1.10 m long vertical thin-section profile covering approximately five annual cycles has been obtained from the North Greenland Icecore Project (NorthGRIP) ice core at around 301 m depth. The crystal outline and the c-axis orientation of more than 13000 crystals in the profile have been measured on a new Australian automated ice-crystal analyzer. In 2.5 cm resolution we observe a strong seasonal variability in crystal areas of >30%deviation from the average value of 6.7 mm2. Each year, a band of smaller crystals is observed in ice deposited during spring. The area distribution function is found to be close to a lognormal distribution. The crystal areas are compared to the concentration of chemical impurities in the ice; at a 5 cm resolution, the best correlation is found with the concentration of Ca2+. Our results show no seasonal variability of the average c-axis orientation of ice crystals.
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Gagliardini, Olivier, Gaël Durand et Yun Wang. « Grain area as a statistical weight for polycrystal constituents ». Journal of Glaciology 50, no 168 (2004) : 87–95. http://dx.doi.org/10.3189/172756504781830349.
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AbstractBy using recently developed automatic instruments for fabric and texture measurements on ice, both the c-axis orientation and area of the individual crystals can be determined. Each grain can then be associated with its volume fraction, defined as a function of its measured cross-sectional area, to describe the microstructure of a poly-crystal. The relevance of this approach is studied using a three-dimensional microstructure obtained from the Potts model. In particular, the area weighting is compared to the classical implicit equal weighting used by glaciologists, which assumes that all the grains have the same volume fraction (discrete uniform distribution). Then, using the measurements of c-axis orientation and crystal size performed on the North Greenland Icecore Project (NorthGRIP) ice core, we compare area-weighted and equal-weighted fabrics. All these comparisons are made with respect to the orientation tensor. According to the ability of the Potts model to reproduce the ice microstructure, it is shown that using the grain cross-sectional area to infer its volume fraction improves the description of the actual polycrystal fabric.
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Grinsted, Aslak, et Dorthe Dahl-Jensen. « A Monte Carlo-tuned model of the flow in the NorthGRIP area ». Annals of Glaciology 35 (2002) : 527–30. http://dx.doi.org/10.3189/172756402781817130.
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AbstractThe North Greenland Icecore Project (NorthGRIP) drill site was chosen in order to obtain a good Eemian record. At the present depth, 3001 m, the Eemian interstadial has yet to be seen. Clearly the flow in this area is poorly understood and needs further investigation. After a review of specific features of the bottom topography, it is believed that the geology changes along the flowline. In order to investigate whether this explains the observed age–depth relationship at NorthGRIP, the inverse Monte Carlo method has been applied to a simple model. the inversion reveals that the main reason no Eemian is observed is a high basal melt rate (2.7 mma–1). the melting is a consequence of a higher geothermal heat flux than the expected 51 mWm–2 of the Precambrian shield. from our analyses it is concluded that the geothermal heat flux at NorthGRIP is 98 mWm–2.The high basal melt rate also gives rise to sliding at the bed. In addition to these results, an accumulation model has been established specifically for NorthGRIP. These results are essential for further modelling of the NorthGRIP flow and depth–age relationship.
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Rempel, Alan W., et J. S. Wettlaufer. « Isotopic diffusion in polycrystalline ice ». Journal of Glaciology 49, no 166 (2003) : 397–406. http://dx.doi.org/10.3189/172756503781830638.
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AbstractQuantitative ice-core paleoclimatology must account for post-depositional processes, such as vapor-phase diffusion in the firn. After pore close-off, diffusion continues to smooth the stable-isotope records δ18O and δD that are eventually recovered from the ice, leading to the loss of high-frequency information. Johnsen and others (1997) found much higher rates of diffusive smoothing in the Greenland Icecore Project (GRIP) Holocene ice than would be predicted by diffusion through solid ice alone, and Nye (1998) argued that transport through liquid veins might explain this apparent excess diffusion. However, the analysis of Johnsen and others (2000) indicates that the required vein dimensions may be unrealistically large. Here, we model the diffusion of stable isotopes in polycrystalline ice and show that the predictions of Nye (1998) and those of Johnsen and others (2000) actually represent two end-members in a range of potential behavior. Our model determines which of these asymptotic regimes more closely resembles the prevailing conditions and quantifies the role of pre-melted liquid in the smoothing of isotopic signals. The procedure thereby ties together the two approaches and provides a rostrum for accurate analysis of isotope records and paleotemperature reconstructions.
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Hansen, Kaj M., Anders Svensson, Yun Wang et Jørgen Peder Steffensen. « Properties of GRIP ice crystals from around Greenland interstadial 3 ». Annals of Glaciology 35 (2002) : 531–37. http://dx.doi.org/10.3189/172756402781816834.
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AbstractIce-crystal textures (sizes and shapes) and fabrics (c-axis orientations) have been determined in 3 m of vertical thin sections from the Greenland Icecore Project (GRIP) ice core. the samples cover ice from before, during and after Greenland interstadial 3 (IS3) that occurred about 25 kyr BP. the texture of 60 000 crystals has been obtained from stacked digital images by semi-automated methods, and the fabric of 5000 selected crystals has been measured on the Automatic Ice Fabric Analyzer at the Alfred Wegener Institute, Bremerhaven. the area distribution function of the crystals is close to a log normal distribution, and the mean area is found to be 3.36 mm2 in ice from IS3, and 3.04 mm2 in ice from colder periods before and after IS3. the overall c-axis orientations show a strong single maximum with vertical orientation. These results agree well with earlier GRIP fabric studies obtained by manual methods. from comparisons of crystal areas with the concentrations of dust, Ca2+, SO42–, Cl– and NO3– in the ice we determine that NO3– correlates best with crystal areas. Crystals within clearly visible cloudy bands are significantly smaller than the surrounding crystals, and their c-axis orientations are less well confined than the average.
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Ruth, Urs, Dietmar Wagenbach, Matthias Bigler, Jørgen P. Steffensen, Regine Röthlisberger et Heinz Miller. « High-resolution microparticle profiles at NorthGRIP, Greenland : case studies of the calcium–dust relationship ». Annals of Glaciology 35 (2002) : 237–42. http://dx.doi.org/10.3189/172756402781817347.
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AbstractA novel flow-through microparticle detector was deployed concurrently with continuous flow analyses of major ions during the North Greenland Icecore Project 2000 field season. the easy-handling detector performs continuous counting and sizing. In this deployment the lower size-detection limit was conservatively set to 1.0 μm equivalent spherical particle diameter, and a depth resolution of ≤1cm was achieved for microparticle concentrations. the dust concentration usually followed the Ca2+ variability. Here results are presented from an inspection of the Ca/dust mass ratio in 23 selected intervals, 1.65 m long each, covering different climatic periods including Holocene and Last Glacial Maximum (LGM). A (Ca2+)/(insoluble dust) mass ratio of 0.29 was found for the Holocene and 0.11 for LGM. Changes to the Ca/dust ratio occur on an annual to multi-annual time-scale exhibiting the same pattern, i.e. a lower Ca/dust ratio for higher crustal concentrations. Moreover, the Ca2+/dust ratio may increase significantly during episodic events such as volcanic horizons due to enhanced dissolution of CaCO3. This calls into question the notion of deploying Ca2+ as a quantitative mineral dust reference species and shows the importance of variable source properties or fractionating processes during transport and deposition.
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Waddington, Edwin D., John F. Bolzan et Richard B. Alley. « Potential for stratigraphie folding near ice-sheet centers ». Journal of Glaciology 47, no 159 (2001) : 639–48. http://dx.doi.org/10.3189/172756501781831756.
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AbstractLack of agreement between the deep portions of the Greenland Icecore Project (GRIP) and Greenland Ice Sheet Project II (GISP2) ice cores from central Greenland suggests that folds may disrupt annual layering, even near ice divides. We use a simple kinematic flow model to delineate regions where slope disturbances (“wrinkles”) introduced into the layering could overturn into recumbent folds, and where they would flatten, leaving the stratigraphic record intact. Wrinkles are likely to originate from flow disturbances caused internally by inhomogeneities and anisotropy in the ice rheological properties, rather than from residual surface structures (sastrugi), or from open folds associated with transient flow over bed topography. If wrinkles are preferentially created in anisotropic ice under divides, where the resolved shear stress in the easy-glide direction can be weak and variable, then the deep intact climate record at Dye 3 may result from its greater distance from the divide. Alternatively, the larger simple shear at Dye 3 may rapidly overturn wrinkles, so that they are not recognizable as folds. The ice-core record from Siple Dome may be intact over a greater fraction of its depth compared to the central Greenland records if its flat bedrock precludes fluctuations in the stress orientation near the divide.
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Forsström, Pirjo-Leena, Olli Sallasmaa, Ralf Greve et Thomas Zwinger. « Simulation of fast-flow features of the Fennoscandian ice sheet during the Last Glacial Maximum ». Annals of Glaciology 37 (2003) : 383–89. http://dx.doi.org/10.3189/172756403781815500.
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AbstractIn order to reconstruct the palaeoglaciation in Fennoscandia and northern Asia during the late-Weichselian ice-age phase, simulations with the dynamic and thermodynamic ice-sheet model SICOPOLIS are carried out. Our focus is on the Last Glacial Maximum (LGM) around 20 kyr BP. Climate forcing is based on mean annualsur-face temperature and precipitation derived from present data and Palaeoclimatic Modelling Intercomparison Project (PMIP) UKMO21 results for the LGM. These distributions are interpolated via a glacial index defined by the Greenland Icecore Project (GRIP) δ18O record. The extent of the Scandinavian and the Barents ice sheets is reproduced in good agreement with the Quaternary Environments of the Eurasian North (QUEEN) reconstruction, but the Kara Sea and Taymyr Peninsula areas are excessively glaciated. The fast-flow regions derived from the simulations, which are generally connected to regions with a temperate base and temperate ice above, are compared to hypothesized palaeo-ice-stream locations, especially in the Norwegian Channel and the Baltic area. In the Norwegian Channel, temperate basal conditions with temperate ice above prevail and favour fast flow. In the Baltic area, ice-sheet advance is generally accompanied by slow ice velocities (<200 m a–1). Some temporary fast-flow features occur due to transitional temperate-base conditions, and higher velocities arise in retreat phases.
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Worton, D. R., W. T. Sturges, J. Schwander, R. Mulvaney, J. M. Barnola et J. Chappellaz. « 20th Century trends and budget implications of trihalomethanes and dihalomethanes inferred from North GRIP firn air ». Atmospheric Chemistry and Physics Discussions 6, no 1 (24 janvier 2006) : 701–54. http://dx.doi.org/10.5194/acpd-6-701-2006.
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Abstract. Four trihalomethane (THM; CHCl3, CHBrCl2, CHBr2Cl and CHBr3) and two dihalomethane (DHM; CH2BrCl and CH2Br2) trace gases have been measured in air extracted from polar firn collected at the North Greenland Icecore Project (NGRIP) site. CHCl3 was also measured in firn air from Devon Island (DI), Canada, Dronning Maud Land (DML), Antarctica and Dome Concordia (Dome C), Antarctica. All of these species are believed to be almost entirely of natural origin except for CHCl3 where anthropogenic sources have been reported to contribute ~10% to the global burden. A 2-D atmospheric model was run for CHCl3 using reported emission estimates to produce historical atmospheric trends at the three firn sites, which were then input into a firn diffusion model to produce concentration depth profiles that were compared against the measurements. The anthropogenic emissions were modified in order to give the best model fit to the firn data at NGRIP, Dome C and DML. As a result, the contribution of CHCl3 from anthropogenic sources, mainly from pulp and paper manufacture, to the total chloroform budget appears to have been considerably underestimated and was likely to have been close to ~40% at the maximum in atmospheric CHCl3 concentrations around 1990, declining to ~19% at the beginning of the 21st Century. We also show that the atmospheric burden of the brominated THM's in the northern hemisphere have increased over the 20th Century while CH2Br2 has remained constant over time implying that it is entirely of natural origin.
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Worton, D. R., W. T. Sturges, J. Schwander, R. Mulvaney, J. M. Barnola et J. Chappellaz. « 20th century trends and budget implications of chloroform and related tri-and dihalomethanes inferred from firn air ». Atmospheric Chemistry and Physics 6, no 10 (12 juillet 2006) : 2847–63. http://dx.doi.org/10.5194/acp-6-2847-2006.
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Abstract. Four trihalomethane (THM; CHCl3, CHBrCl2, CHBr2Cl and CHBr3) and two dihalomethane (DHM; CH2BrCl and CH2Br2) trace gases have been measured in air extracted from polar firn collected at the North Greenland Icecore Project (NGRIP) site. CHCl3 was also measured in firn air from Devon Island (DI), Canada, Dronning Maud Land (DML), Antarctica and Dome Concordia (Dome C), Antarctica. All of these species are believed to be almost entirely of natural origin except for CHCl3 where anthropogenic sources have been reported to contribute ~10% to the global burden. A 2-D atmospheric model was run for CHCl3 using reported emission estimates to produce historical atmospheric trends at the firn sites, which were then input into a firn diffusion model to produce concentration depth profiles that were compared against the measurements. The anthropogenic emissions were modified in order to give the best model fit to the firn data at NGRIP, Dome C and DML. As a result, the contribution of CHCl3 from anthropogenic sources, mainly from pulp and paper manufacture, to the total chloroform budget appears to have been considerably underestimated and was likely to have been close to ~50% at the maximum in atmospheric CHCl3 concentrations around 1990, declining to ~29% at the beginning of the 21st century. We also show that the atmospheric burden of the brominated THM's in the Northern Hemisphere have increased over the 20th century while CH2Br2 has remained constant over time implying that it is entirely of natural origin.
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Mogensen, Irene A., Sigfüs J. Johnsen, Andrey Ganopolski et Stefan Rahmstorf. « An investigation of rapid warm transitions during MIS2 and MIS3 using Greenland ice-core data and the CLIMBER-2 model ». Annals of Glaciology 35 (2002) : 398–402. http://dx.doi.org/10.3189/172756402781816654.
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AbstractIn the search for abetter understanding of the dominant mechanisms of the Earth’s climate system, we present a study of rapid warm-climate transitions to Dansgaard– Oeschger events as seen in the ice cores from the Greenland ice sheet. We present a continuous δ18O record from the Greenland Icecore Project (GRIP) core with a resolution of 5 years until 50 kyr BP and of 20 years until 100 kyr BP. These data are compared with other high-resolution records, i.e. the Greenland Ice Sheet Project II (GISP2) chemistry record (25 years until 50 kyr BP) and the GRIP Ca2+ record (3 years until 100 kyr BP). All records have been transformed to the GISP2 Meese/Sowers time-scale. the high-resolution records are separated into interstadials and stadials, defined by the GRIP and GISP2 δ18O records. We examine in detail the transitions into the Dansgaard–Oeschger events, and propose a scenario for the changes that occur in the different ice-core records during the approximately 50 years the transition takes. Themain difference from previous studies is the much higher-resolution datasets available until 50 kyr BP; previous high-resolution studies by Taylor and others (1997) have focused on only the Younger Dryas/Preboreal transition. the data are compared to model simulations of the Dansgaard–Oeschger events performed with the CLIMBER-2 model of intermediate complexity (Petoukhov and others, 1998 ; Ganopolski and Rahmstorf, 2001).
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Gillet-Chaulet, Fabie, Olivier Gagliardini, Jacques Meyssonnier, Maurine Montagnat et Olivier Castelnau. « A user-friendly anisotropic flow law for ice-sheet modeling ». Journal of Glaciology 51, no 172 (2005) : 3–14. http://dx.doi.org/10.3189/172756505781829584.
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AbstractFor accurate ice-sheet flow modelling, the anisotropic behaviour of ice must be taken fully into account. However, physically based micro-macro (μ-M) models for the behaviour of an anisotropic ice polycrystal are too complex to be implemented easily in large-scale ice-sheet flow models. An easy and efficient method to remedy this is presented. Polar ice is assumed to behave as a linearly viscous orthotropic material whose general flow law (GOLF) depends on six parameters, and its orthotropic fabric is described by an ‘orientation distribution function’ (ODF) depending on two parameters. A method to pass from the ODF to a discrete description of the fabric, and vice versa, is presented. Considering any available μ-M model, the parameters of the GOLF that fit the response obtained by running this μ-M model are calculated for any set of ODF parameters. It is thus possible to tabulate the GOLF over a grid in the space of the ODF parameters. This step is performed once and for all. Ice-sheet flow models need the general form of the GOLF to be implemented in the available code (once), then, during each individual run, to retrieve the GOLF parameters from the table by interpolation. As an application example, the GOLF is tabulated using three different μ-M models and used to derive the rheological properties of ice along the Greenland Icecore Project (GRIP) ice core.
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Ditlevsen, Peter D., Susanne Ditlevsen et Katrine K. Andersen. « The fast climate fluctuations during the stadial and interstadial climate states ». Annals of Glaciology 35 (2002) : 457–62. http://dx.doi.org/10.3189/172756402781816870.
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AbstractRapid climate changes during the last glacial period were first observed in ice-core records (Dansgaard and others, 1982). These shifts between interstadials, called Dansgaard–Oeschger (D-O) events, and stadials or deep glaciation were later seen in Atlantic sediment records (Bond and others, 1993), pointing to the ocean circulation as a strong component in the dynamics of these shifts (Wright and Stocker, 1991). the interstadial states are observed to have a characteristic ``sawtooth’’ shape, indicating a gradual drift of the stable interstadial state toward the stable stadial state. In order to contrast the two climate states, we have separated the δ18O signal from the Greenland Icecore Project ice core into periods corresponding to the two states. the climate variability in the two different climatic states is different (Johnsen and others, 1997). We find that the standard deviation is significantly larger in the stadial than in the interstadial state. Both states are found to have a larger standard deviation than the Holocene part of the record. the correlation times in the different states are difficult to obtain because of limited data resolution and diffusion of the isotopic signal. However, using a statistical technique, we have estimated the correlation times. We do not find significant differences in the correlation times, which are of the order of months, in the different climatic states. These findings are interpreted in the context of a simple linear stochastic model which provides information about the relative roles of the climatic forcing and the stability of the climate state governing the climate variability.
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Frechen, Manfred, Birgit Terhorst et Wolfgang Rähle. « The Upper Pleistocene loess/palaeosol sequence from Schatthausen in North Baden-Württemberg ». E&G Quaternary Science Journal 56, no 3 (1 septembre 2007) : 212–27. http://dx.doi.org/10.3285/eg.56.3.05.
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Abstract. The loess/palaeosol sequence from the section at Schatthausen in North Baden-Württemberg gives evidence for a younger Bt horizon superimposing the last interglacial palaeosol. This result requires a more careful investigation of polygenetic superimposing palaeosols to avoid misinterpretation of the chronostratigraphic positions. The humic horizon and the underlying Bt horizon were most likely formed during two soil forming periods, as evidenced by means of palaeopedology, phytoliths and luminescence dating. The lowermost Bt horizon (Bt1) was most likely formed during the Eemian interglacial, marine isotope substage (MIS) 5e. The sediment of the uppermost Bt horizon (Bt2) was deposited about 71.5±7.4 ka ago and subsequently superimposed by soil formation most likely during early MIS 3. The Ah horizon covering the Bt gave infrared optically stimulated luminescence (IRSL) age estimates between 52.5±5.5 ka and 45.4±4.7 ka confirming soil formation during MIS 3. Periods of increased dust accumulation rates can be distinguished for the loess/palaeosol sequence by IRSL age estimates. These are from the youngest to the oldest: The Late Glacial loess (MIS 2) with a weighted mean age of 15.2±0.6 ka (N=7), the Middle Pleniglacial sediments (MIS 3) with a weighted mean age of 48.9±2.5 ka (n=4) and the Lower Pleniglacial/Early Glacial sediments (MIS 4/MIS 5) with a deposition age of 71.5±7.4 ka and older loess deposits. The IRSL age estimates are in excellent agreement with the geological estimates and correlate well with the dust peaks of Greenland Icecore record (GRIP). The loess record from Schatthausen complements the loess/palaeosol sequence from the nearby Nußloch section with the late glacial loess and its intercalcated Cryic Gleysols.
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Steinhage, Daniel, Olaf Eisen et Henrik Brink Clausen. « Regional and temporal variation of accumulation around NorthGRIP derived from ground-penetrating radar ». Annals of Glaciology 42 (2005) : 326–30. http://dx.doi.org/10.3189/172756405781812574.
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AbstractDuring the summer of 2003, a ground-penetrating radar survey around the North Greenland Icecore Project (NorthGRIP) deep ice-core drilling site (75˚06’N, 42˚20’W; 2957ma.s.l.) was carried out using a shielded 250 MHz radar system. The drill site is located on an ice divide, roughly 300 km north-northwest of the summit of the Greenland ice sheet. More than 430 km of profiles were measured, covering a 10 km by 10 km area, with a grid centered on the drilling location, and eight profiles extending beyond this grid. Seven internal horizons within the upper 120 m of the ice sheet were continuously tracked, containing the last 400 years of accumulation history. Based on the age-depth and density-depth distribution of the deep core, the internal layers have been dated and the regional and temporal distribution of accumulation rate in the vicinity of NorthGRIP has been derived. The distribution of accumulation shows a relatively smoothly increasing trend from east to west from 145 kgm–2a–1 to 200 kg m–2 a -1 over a distance of 50 km across the ice divide. The general trend is overlain by small-scale variations on the order of 2.5 kgm–2a-1 km- 1 , i.e. around 1.5% of the accumulation mean. The temporal variations of the seven periods defined by the seven tracked isochrones are on the order of ± 4% of the mean of the last 400 years, i.e. at NorthGRIP ± 7 kg m–2 a-1. If the regional accumulation pattern has been stable for the last several thousand years during the Holocene, and ice flow has been comparable to today, advective effects along the particle trajectory upstream of NorthGRIP do not have a significant effect on the interpretation of climatically induced changes in accumulation rates derived from the deep ice core over the last 10 kyr.
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Eicken, Hajo, Manfred A. Lange et Peter Wadhams. « Characteristics and distribution patterns of snow and meteoric ice in the Weddell Sea and their contribution to the mass balance of sea ice ». Annales Geophysicae 12, no 1 (31 janvier 1994) : 80–93. http://dx.doi.org/10.1007/s00585-994-0080-x.
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Abstract. Based on snow- and ice-thickness measurements at >11 000 points augmented by snow- and icecore studies during 4 expeditions from 1986 - 92 in the Weddell Sea, we describe characteristics and distribution patterns of snow and meteoric ice and assess their importance for the mass balance of sea ice. For first-year ice (FY) in the central and eastern Weddell Sea, mean snow depth amounts to 0.16 m (mean ice thickness 0.75 m) compared to 0.53 m (mean ice thickness 1.70 m) for second-year ice (SY) in the northwestern Weddell Sea. Ridged ice retains a thicker snow cover than level ice, with ice thickness and snow depth negatively correlated for the latter, most likely due to aeolian redistribution. During the different expeditions, 8, 15, 17 and 40% of all drill holes exhibited negative freeboard. As a result of flooding and brine seepage into the snow pack, snow salinities averaged 4‰. Through 18O measurements the distribution of meteoric ice (i.e. precipitation) in the sea-ice cover was assessed. Roughly 4% of the total ice thickness consist of meteoric ice (FY 3%, SY 5%). With a mean density of 290 kg/m3, the snow cover itself contributes 8% to total ice mass (7% FY, 11% SY). Analysis of ∆18O in snow indicates a local maximum in accumulation in the 65 to 75°S latitude zone. Hydrogen peroxide in the snow has proven useful as a temporal tracer and for identification of second-year floes. Drawing on accumulation data from stations at the Weddell Sea coast, it becomes clear that the onset of ice growth is important for the evolution of ice thickness and the interaction between ice and snow. Loss of snow to leads due to wind drift may be considerable, yet is reduced owing to metamorphic processes in the snow column. This is confirmed by a comparison of accumulation data from coastal stations and from snow depths over sea ice. Temporal and spatial accumulation patterns of snow are shown to be important in controlling the sea-ice cover evolution.
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Gaisser, Thomas, et Francis Halzen. « IceCube ». Annual Review of Nuclear and Particle Science 64, no 1 (19 octobre 2014) : 101–23. http://dx.doi.org/10.1146/annurev-nucl-102313-025321.
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de los Heros, Carlos P. « IceCube ». Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment 630, no 1 (février 2011) : 119–24. http://dx.doi.org/10.1016/j.nima.2010.06.042.
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Giommi, P., T. Glauch, P. Padovani, E. Resconi, A. Turcati et Y. L. Chang. « Dissecting the regions around IceCube high-energy neutrinos : growing evidence for the blazar connection ». Monthly Notices of the Royal Astronomical Society 497, no 1 (16 juillet 2020) : 865–78. http://dx.doi.org/10.1093/mnras/staa2082.
Texte intégralRésumé :
ABSTRACT The association of two IceCube detections, the IceCube-170922A event and a neutrino flare, with the blazar TXS 0506+056, has paved the way for the multimessenger quest for cosmic accelerators. IceCube has observed many other neutrinos but their origin remains unknown. To better understand the reason for the apparent lack of neutrino counterparts, we have extended the comprehensive dissection of the sky area performed for the IceCube-170922A event to all 70 public IceCube high-energy neutrinos that are well reconstructed and off the Galactic plane. Using the multifrequency data available through the Open Universe platform, we have identified numerous candidate counterparts of IceCube events. We report here the classification of all the γ-ray blazars found and the results of subsequent statistical tests. In addition, we have checked the 4LAC, 3FHL, and 3HSP catalogues for potential counterparts. Following the dissection of all areas associated with IceCube neutrinos, we evaluate the data using a likelihood-ratio test and find a $3.23\, \sigma$ (post-trial) excess of HBLs and IBLs with a best fit of 15 ± 3.6 signal sources. This result, together with previous findings, consistently points to a growing evidence for a connection between IceCube neutrinos and blazars, the most energetic particle accelerators known in the Universe.
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Gress, O. A., V. M. Lipunov, D. Dornic, E. S. Gorbovskoy, V. G. Kornilov, N. V. Tyurina, P. V. Balanutsa, A. S. Kuznetsov, V. V. Vladimirov et D. A. Kuvshinov. « MASTER INVESTIGATION OF ANTARES AND ICECUBE ALERTS ». Revista Mexicana de Astronomía y Astrofísica Serie de Conferencias 51 (13 avril 2019) : 89–95. http://dx.doi.org/10.22201/ia.14052059p.2019.51.15.
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This paper presents the first investigation results of possible coincidences of optical transients in the MASTER global robotic telescope net database with the localization regions of VHE and UHE neutrino alert events from ANTARES and IceCube observatories. MASTER is the first robotic telescopic system in Russia, dedicated to optical observation and registration of the most energetic and fastest explosive processes in the Universe. The goal is a deeper and more thorough study of space and time coincidences of the MASTER optical transients and high energy neutrinos.
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Williams, Dawn. « Recent Results from IceCube ». International Journal of Modern Physics : Conference Series 46 (janvier 2018) : 1860048. http://dx.doi.org/10.1142/s2010194518600480.
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The IceCube Neutrino Observatory is a cubic kilometer detector located at the geographic South Pole. IceCube was designed to detect high-energy neutrinos from cosmic sources, and the DeepCore extension of IceCube enables the study of atmospheric neutrino interactions down to energies of a few GeV. IceCube has detected a diffuse flux of neutrinos in the energy range from 100 TeV to several PeV, the properties of which are inconsistent with an atmospheric origin, and has also published competitive limits on atmospheric neutrino oscillation parameters and other neutrino properties. This paper presents the latest results from IceCube and prospects for future upgrades and expansions of the detector.
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ABBASI, RASHA. « ICECUBE NEUTRINO OBSERVATORY ». International Journal of Modern Physics D 19, no 06 (juin 2010) : 1041–48. http://dx.doi.org/10.1142/s021827181001697x.
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This contribution is a brief report on the IceCube kilometer cubed neutrino telescope located at the geographical South Pole. IceCube construction is on schedule to be completed in 2011. The full detector will consist of 86 strings, each with 60 digital optical modules. At the time of writing 59 strings of IceCube are taking data. Based on the data taken to date, the telescope meets its design goals. Selected results of ongoing analysis of IceCube detector data are presented.
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Halzen, Francis. « IceCube Science ». Journal of Physics : Conference Series 171 (1 juin 2009) : 012014. http://dx.doi.org/10.1088/1742-6596/171/1/012014.
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Halzen, Francis. « IceCube Science ». Journal of Physics : Conference Series 173 (1 juin 2009) : 012021. http://dx.doi.org/10.1088/1742-6596/173/1/012021.
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Mann, Adam. « IceCube completed ». Nature 469, no 7328 (29 décembre 2010) : 13. http://dx.doi.org/10.1038/469013a.
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Meagher, Kevin J. « Neutrino Astronomy with IceCube ». Proceedings of the International Astronomical Union 12, S324 (septembre 2016) : 322–29. http://dx.doi.org/10.1017/s1743921317002307.
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AbstractThe IceCube Neutrino Observatory is a cubic kilometer neutrino telescope located at the Geographic South Pole. Cherenkov radiation emitted by charged secondary particles from neutrino interactions is observed by IceCube using an array of 5160 photomultiplier tubes embedded between a depth of 1.5 km to 2.5 km in the Antarctic glacial ice. The detection of astrophysical neutrinos is a primary goal of IceCube and has now been realized with the discovery of a diffuse, high-energy flux consisting of neutrino events from tens of TeV up to several PeV. Many analyses have been performed to identify the source of these neutrinos: correlations with active galactic nuclei, gamma-ray bursts, and the galactic plane. IceCube also conducts multi-messenger campaigns to alert other observatories of possible neutrino transients in real-time. However, the source of these neutrinos remains elusive as no corresponding electromagnetic counterparts have been identified. This proceeding will give an overview of the detection principles of IceCube, the properties of the observed astrophysical neutrinos, the search for corresponding sources (including real-time searches), and plans for a next-generation neutrino detector, IceCube–Gen2.
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Clark, B. A. « The IceCube-Gen2 Neutrino Observatory ». Journal of Instrumentation 16, no 10 (1 octobre 2021) : C10007. http://dx.doi.org/10.1088/1748-0221/16/10/c10007.
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Abstract The IceCube Neutrino Observatory opened the window on neutrino astronomy by discovering high-energy astrophysical neutrinos in 2013 and identifying the first compelling astrophysical neutrino source, the blazar TXS0506 + 056, in 2017. In this proceeding, we will discuss the science reach and ongoing development of the IceCube-Gen2 facility, which is the planned extension to IceCube. IceCube-Gen2 will increase the rate of observed cosmic neutrinos by an order of magnitude, be able to detect five-times fainter neutrino sources, and extend the measurement of astrophysical neutrinos several orders of magnitude higher in energy. We will discuss the envisioned design of the instrument, which will include an enlarged in-ice optical array, a surface array for the study of cosmic-rays, and a shallow radio array to detect ultra-high energy (>100 PeV) neutrinos. We will also highlight ongoing efforts to develop and test new instrumentation for IceCube-Gen2.
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TABOADA, IGNACIO. « A REVIEW OF PARTICLE ASTROPHYSICS WITH ICECUBE ». Modern Physics Letters A 27, no 39 (13 décembre 2012) : 1230042. http://dx.doi.org/10.1142/s021773231230042x.
Texte intégralRésumé :
IceCube is a neutrino detector sensitive to energies above 10 GeV. IceCube operates by sensing the Cherenkov light from secondary particles produced in neutrino-matter interactions. One gigaton of highly transparent Antarctic ice is instrumented to achieve this goal. Designed to be modular, IceCube has been collecting data since construction began in 2005. Construction was completed in December 2010. The primary goal of IceCube is to observe astrophysical sources of neutrinos. We present here a summary of IceCube's recent results in atmospheric neutrinos, point sources, diffuse fluxes of neutrinos, cosmogenic neutrinos, a lack of correlation between neutrinos and Gamma Ray Bursts and the search for dark matter.
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Savard, Katherine, John J. Ruan et Daryl Haggard. « Are blazars above the blazar sequence a significant source of IceCube neutrinos ? » Monthly Notices of the Royal Astronomical Society 509, no 3 (11 novembre 2021) : 4620–25. http://dx.doi.org/10.1093/mnras/stab3207.
Texte intégralRésumé :
ABSTRACT The recent association of two flaring blazars (TXS 0506+056 and 3HSP J095507.9+355101) with IceCube neutrinos strongly suggests that blazars are at least one source of high-energy neutrinos. A peculiar characteristic of these two blazars is that they both appear to lie above the well-known blazar sequence, and they move further above the blazar sequence during the neutrino emission. Although the reason for this peculiarity is unclear, it may indicate a link between blazar SED properties and neutrino emission. Here, we test whether blazars lying above the blazar sequence are overrepresented in IceCube neutrino error regions. We spatially cross-match IceCube error regions with a sample of γ-ray blazars from the Fermi-LAT 4LAC catalogue, as a function of the blazars’ distance in synchrotron peak frequency above the blazar sequence. We do not find a statistically significant excess of counterparts, and thus conclude that the current data cannot confirm that the sources above the blazar sequence are a significant source of IceCube neutrinos. However, we show that the inclusion of more recently detected IceCube events increases the likelihood of an excess of blazars above the blazar sequence, and suggest that this excess may reach statistical significance in the future as the sample of IceCube neutrino detections increases.
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DeYOUNG, TYCE. « NEUTRINO ASTRONOMY WITH ICECUBE ». Modern Physics Letters A 24, no 20 (28 juin 2009) : 1543–57. http://dx.doi.org/10.1142/s0217732309031417.
Texte intégralRésumé :
IceCube is a kilometer-scale high energy neutrino telescope under construction at the South Pole, a second-generation instrument expanding the capabilities of the AMANDA telescope. The scientific portfolio of IceCube includes the detection of neutrinos from astrophysical objects such as the sources of the cosmic rays, the search for dark matter, and fundamental physics using a very large data set of atmospheric neutrinos. The design and status of IceCube are briefly reviewed, followed by a summary of results to date from AMANDA and initial IceCube results from the 2007 run, with 22 of a planned 86 strings operational. The new infill array known as Deep Core, which will extend IceCube's capabilities to energies as low as 10 GeV, is also described.
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Reimann, René. « Monitoring and Multi-Messenger Astronomy with IceCube ». Galaxies 7, no 1 (19 mars 2019) : 40. http://dx.doi.org/10.3390/galaxies7010040.
Texte intégralRésumé :
IceCube currently is the largest neutrino observatory with an instrumented detection volume of 1 km3 buried in the ice-sheet close to the antarctic South Pole station. With a 4 π field of view and an up-time of >99%, it is continuously monitoring the full sky to detect astrophysical neutrinos. With the detection of an astrophysical neutrino flux in 2013, IceCube opened a new observation window to the non-thermal Universe. The IceCube collaboration has a large program to search for astrophysical neutrinos, including measurements of the energy spectrum of the diffuse astrophysical flux, auto- and cross-correlation studies with other multi-messenger particles, and a real-time alert and follow-up system. On 22 September 2017, the IceCube online system sent out an alert reporting a high-energy neutrino event. This alert triggered a series of multi-wavelength follow-up observations that revealed a spatially-coincident blazar TXS 0506+056, which was also in an active flaring state. This correlation was estimated at a 3 σ level. Further observations confirmed the flaring emission in the very-high-energy gamma-ray band. In addition, IceCube found an independent 3.5 σ excess of a time-variable neutrino flux in the direction of TXS 0506+056 two years prior to the alert by examining 9.5 years of archival neutrino data. These are the first multi-messenger observations of an extra-galactic astrophysical source including neutrinos since the observation of the supernova SN1987A. This review summarizes the different detection and analysis channels for astrophysical neutrinos in IceCube, focusing on the multi-messenger program of IceCube and its major scientific results.
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Das, Saikat, Soebur Razzaque et Nayantara Gupta. « Cosmogenic gamma-ray and neutrino fluxes from blazars associated with IceCube events ». Astronomy & ; Astrophysics 658 (février 2022) : L6. http://dx.doi.org/10.1051/0004-6361/202142123.
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Context. Blazars constitute the vast majority of extragalactic γ-ray sources. They can also contribute a sizable fraction of the diffuse astrophysical neutrinos detected by IceCube. In the past few years, the real-time alert system of IceCube has led to the multiwavelength follow-up of very high-energy neutrino events of plausible astrophysical origin. Spatial and temporal coincidences of a number of these neutrino events with γ-ray blazars provide a unique opportunity to decipher cosmic-ray interactions in the relativistic jets. Aims. The aim of this work is to test if the γ-ray blazars associated with the IceCube neutrino events are also sources of ultra-high-energy cosmic rays (UHECRs; E > 1018 eV). Methods. Assuming that blazars accelerate UHECRs, we calculate the “guaranteed” contribution to the line-of-sight cosmogenic γ-ray and neutrino fluxes from four blazars associated with IceCube neutrino events. We compare these fluxes with the sensitivities of the upcoming γ-ray imaging telescopes, such as the CTA, and with the planned neutrino detectors, such as IceCube-Gen2. Results. We find that detection of the cosmogenic neutrino fluxes from the blazars TXS 0506+056, PKS 1502+106, and GB6 J1040+0617 would require UHECR luminosity ≳10 times the inferred neutrino luminosity from the associated IceCube events, with the maximum UHECR proton energy Ep, max ≈ 1020 eV. Cosmogenic γ-ray emission from blazars TXS 0506+056, 3HSP J095507.9 +355101, and GB6 J1040+0617 can be detected by the CTA if the UHECR luminosity is ≳10 times the neutrino luminosity inferred from the associated IceCube events and for Ep, max ≳ 1019 eV. Conclusions. Detection of cosmogenic neutrino and/or γ-ray flux(es) from blazars associated with IceCube neutrinos may lead to the first direct signature(s) of UHECR sources. Given their relatively low redshifts and hence total energetics, TXS 0506+056 and 3HSP J095507.9+355101 should be the prime targets for upcoming large neutrino and γ-ray telescopes.
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Gaisser, Thomas K. « The IceCube Neutrino Telescope ». Proceedings of the International Astronomical Union 8, S288 (août 2012) : 105–14. http://dx.doi.org/10.1017/s1743921312016742.
Texte intégralRésumé :
AbstractConstruction of IceCube at the Amundsen-Scott South Pole Station was completed at the end of 2010 after eight construction seasons. The detector consists of 5,160 digital optical modules on 86 cables with 60 modules each, viewing in total a cubic kilometer of ice between 1,450 and 2,450 meters below the surface. IceCube includes a sub-array called DeepCore consisting of 8 special cables, and providing a more densely instrumented region with a lower energy threshold in the deep center of the array. IceCube also includes an air shower array called IceTop directly above the deep detector. Optical modules in all three components of the detector are fully integrated into a single data acquisition system. Data taking and analysis began during construction and continues with the completed detector. This paper describes recent results from IceCube.
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Taboada, Ignacio. « IceCube : An overview of physics results ». EPJ Web of Conferences 207 (2019) : 01002. http://dx.doi.org/10.1051/epjconf/201920701002.
Texte intégralRésumé :
Cosmic rays and neutrinos are intimately related. And though TeVPeV astrophysical neutrinos have been observed, their sources and their relation to potential sources of cosmic rays remain unknown. Recently, the blazar TXS 0506+056 has been identified as a candidate neutrino source. In parallel, IceCube has conducted numerous searches for other potential neutrino neutrino sources. These proceedings are limited in scope, given the large breath of science results by IceCube: A description of the astrophysical neutrino flux; a review of the real-time program that enables multi-messenger follow-up of neutrinos; a summary of the observations of TXS 0506+056; a recap of the search for neutrino point sources with 7 years of IceCube data; an account of the tantalizing capabilities of IceCube and ANTARES to detect Milky Way neutrinos and a description of a method to identify Glashow resonance events.
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DEYOUNG, T. « STATUS OF THE ICECUBE NEUTRINO TELESCOPE ». International Journal of Modern Physics A 20, no 14 (10 juin 2005) : 3160–62. http://dx.doi.org/10.1142/s0217751x05026029.
Texte intégralRésumé :
IceCube is a kilometer-scale deep-ice neutrino telescope, to be constructed at the South Pole beginning in January 2005. The concept and design of IceCube, its science goals, present status, and expected performance will be discussed.
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Brunner, Jürgen. « IceCube and ANTARES ». EPJ Web of Conferences 52 (2013) : 09005. http://dx.doi.org/10.1051/epjconf/20135209005.
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DeYoung, Tyce. « Results from IceCube ». EPJ Web of Conferences 116 (2016) : 11004. http://dx.doi.org/10.1051/epjconf/201611611004.
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Mueck, Leonie. « The IceCube chronicles ». Nature Physics 14, no 1 (janvier 2018) : 6. http://dx.doi.org/10.1038/nphys4326.
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Brik, Vladimir, Patrick Meade, Gonzalo Merino, Jan Oertlin, David Schultz et Heath Skarlupka. « IceCube File Catalog ». EPJ Web of Conferences 214 (2019) : 04055. http://dx.doi.org/10.1051/epjconf/201921404055.
Texte intégralRésumé :
IceCube is a cubic kilometer neutrino detector located at the south pole. Metadata for files in IceCube have traditionally been handled on an application by application basis, with no user-facing access. There has been no unified view of data files, and users often query the filesystem to locate files. Recently effort has been put into creating a unified view in a central metadata catalog. Going for a simple solution, we created a userfacing REST API backed by a NoSQL database. All major data producers add their metadata to this central catalog. Schema generation is identified as an important aspect of multi-application metadata services.
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Klein, Spencer R., et the IceCube Collaboration. « Recentvs from IceCube ». Journal of Physics : Conference Series 136, no 2 (1 novembre 2008) : 022050. http://dx.doi.org/10.1088/1742-6596/136/2/022050.
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Berghaus, P. « Muons in IceCube ». Nuclear Physics B - Proceedings Supplements 196 (décembre 2009) : 261–66. http://dx.doi.org/10.1016/j.nuclphysbps.2009.09.050.
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