Pub Date : 2008-11-20DOI: 10.1007/978-3-642-00576-3_16
C. Fendt
{"title":"Magnetohydrodynamic Jets from Different Magnetic Field Configurations","authors":"C. Fendt","doi":"10.1007/978-3-642-00576-3_16","DOIUrl":"https://doi.org/10.1007/978-3-642-00576-3_16","url":null,"abstract":"","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75668686","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 : 2008-11-19DOI: 10.1051/0004-6361:200810467
A. Pereyra, A. Magalhães, F. X. D. Araújo
Aims: To detect line effects using spectropolarimetry in order to find evidence of rotating disks and their respective symmetry axes in T Tauri stars. Methods: We used the IAGPOL imaging polarimeter along with the Eucalyptus-IFU to obtain spectropolarimetric measurements of the T Tauri stars RY Tau (two epochs) and PX Vul (one epoch). Evidence of line effects showing a loop on the Q-U diagram favors a compact rather than an extended source for the line photons in a rotating disk. In addition, the polarization position angle (PA) obtained using the line effect can constrain the symmetry axis of the disk. Results: RY Tau shown a variable Halpha double peak on 2004-2005 data. Polarization line effect is evident on the Q-U diagram for both epochs confirming a clockwise rotating disk. A single loop is evident on 2004 changing to a linear excursion plus a loop on 2005. Interestingly, the intrinsic PA calculated using the line effect is consistent between our two epochs (~167deg). An alternative intrinsic PA computed from the interstellar polarization corrected continuum and averaged between 2001-2005 yielded a PA 137deg. This last value is closer to be perpendicular to the observed disk direction (~25deg) as expected by single scattering in an optically thin disk. For PX Vul, we detected spectral variability in Halpha along with non-variable continuum polarization when compared with previous data. The Q-U diagram shows a well-defined loop in Halpha associated to a counter-clockwise rotating disk. The symmetry axis inferred by the line effect has a PA~91deg (with an ambiguity of 90deg). Our results confirm previous evidence that the emission line in T Tauri stars has its origin in a compact source scattered off a rotating accretion disk.
{"title":"Halpha spectropolarimetry of RY Tau and PX Vul","authors":"A. Pereyra, A. Magalhães, F. X. D. Araújo","doi":"10.1051/0004-6361:200810467","DOIUrl":"https://doi.org/10.1051/0004-6361:200810467","url":null,"abstract":"Aims: To detect line effects using spectropolarimetry in order to find evidence of rotating disks and their respective symmetry axes in T Tauri stars. Methods: We used the IAGPOL imaging polarimeter along with the Eucalyptus-IFU to obtain spectropolarimetric measurements of the T Tauri stars RY Tau (two epochs) and PX Vul (one epoch). Evidence of line effects showing a loop on the Q-U diagram favors a compact rather than an extended source for the line photons in a rotating disk. In addition, the polarization position angle (PA) obtained using the line effect can constrain the symmetry axis of the disk. Results: RY Tau shown a variable Halpha double peak on 2004-2005 data. Polarization line effect is evident on the Q-U diagram for both epochs confirming a clockwise rotating disk. A single loop is evident on 2004 changing to a linear excursion plus a loop on 2005. Interestingly, the intrinsic PA calculated using the line effect is consistent between our two epochs (~167deg). An alternative intrinsic PA computed from the interstellar polarization corrected continuum and averaged between 2001-2005 yielded a PA 137deg. This last value is closer to be perpendicular to the observed disk direction (~25deg) as expected by single scattering in an optically thin disk. For PX Vul, we detected spectral variability in Halpha along with non-variable continuum polarization when compared with previous data. The Q-U diagram shows a well-defined loop in Halpha associated to a counter-clockwise rotating disk. The symmetry axis inferred by the line effect has a PA~91deg (with an ambiguity of 90deg). Our results confirm previous evidence that the emission line in T Tauri stars has its origin in a compact source scattered off a rotating accretion disk.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82755610","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}
Attenuation of high—energy gamma rays by pair—production with UV, optical and IR background photons provides a link between the history of galaxy formation and high—energy astrophysics. We present results from our latest semi‐analytic models (SAMs), based upon a ΛCDM hierachical structural formation scenario and employing all ingredients thought to be important to galaxy formation and evolution, as well as reprocessing of starlight by dust to mid‐ and far‐IR wavelengths. Our models also use results from recent hydrodynamic galaxy merger simulations. These latest SAMs are successful in reproducing a large variety of observational constraints such as number counts, luminosity and mass functions, and color bimodality. We have created 2 models that bracket the likely ranges of galaxy emissivities, and for each of these we show how the optical depth from pair—production is affected by redshift and gamma‐ray energy. We conclude with a discussion of the implications of our work, and how the burgeoning science of...
{"title":"Diffuse Extragalactic Background Radiation","authors":"J. Primack, R. Gilmore, R. Somerville","doi":"10.1063/1.3076779","DOIUrl":"https://doi.org/10.1063/1.3076779","url":null,"abstract":"Attenuation of high—energy gamma rays by pair—production with UV, optical and IR background photons provides a link between the history of galaxy formation and high—energy astrophysics. We present results from our latest semi‐analytic models (SAMs), based upon a ΛCDM hierachical structural formation scenario and employing all ingredients thought to be important to galaxy formation and evolution, as well as reprocessing of starlight by dust to mid‐ and far‐IR wavelengths. Our models also use results from recent hydrodynamic galaxy merger simulations. These latest SAMs are successful in reproducing a large variety of observational constraints such as number counts, luminosity and mass functions, and color bimodality. We have created 2 models that bracket the likely ranges of galaxy emissivities, and for each of these we show how the optical depth from pair—production is affected by redshift and gamma‐ray energy. We conclude with a discussion of the implications of our work, and how the burgeoning science of...","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72912053","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}
While often the point sources in X‐ray surveys are dominated by AGN, with the high sensitivity of modern X‐ray telescopes such as Chandra and XMM‐Newton normal/starburst galaxies are also being detected in large numbers. We have made use of Bayesian statistics for both the selection of galaxies from deep X‐ray surveys and in the analysis of the luminosity functions for galaxies. These techniques can be used to similarly select galaxies from wide‐area X‐ray surveys and to analyze their luminosity function. The prospects for detecting galaxies and AGN from a proposed “wide‐deep” XMM‐Newton survey and from future wide‐area X‐ray survey missions (such as WFXT and eRosita) are also discussed.
{"title":"Wide Area X‐ray Surveys for AGN and Starburst Galaxies","authors":"A. Ptak","doi":"10.1063/1.3059018","DOIUrl":"https://doi.org/10.1063/1.3059018","url":null,"abstract":"While often the point sources in X‐ray surveys are dominated by AGN, with the high sensitivity of modern X‐ray telescopes such as Chandra and XMM‐Newton normal/starburst galaxies are also being detected in large numbers. We have made use of Bayesian statistics for both the selection of galaxies from deep X‐ray surveys and in the analysis of the luminosity functions for galaxies. These techniques can be used to similarly select galaxies from wide‐area X‐ray surveys and to analyze their luminosity function. The prospects for detecting galaxies and AGN from a proposed “wide‐deep” XMM‐Newton survey and from future wide‐area X‐ray survey missions (such as WFXT and eRosita) are also discussed.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81266183","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}
T. Herr, W. Hofmann, for the H.E.S.S. Collaboration
Combining the results of targeted observations, H.E.S.S. has accumulated a large amount of extra‐galactic exposure at TeV energies. Due to its large field of view a considerable part of the sky (0.6 sr) has been observed with high sensitivity outside the targeted observation positions. Since this exposure region contains little inherent bias, it is well suited for studies of extra‐galactic source populations. Given the correlation between ultra‐high energy cosmic rays and nearby extra‐galactic objects recently claimed by the Auger collaboration, this unbiased sky sample by H.E.S.S. is of interest since it includes (besides the targeted sources) 63 AGN within 100 Mpc, for which very‐high energy gamma‐ray flux limits are derived.
{"title":"Very‐High Energy Gamma‐Ray Flux Limits for Nearby Active Galactic Nuclei","authors":"T. Herr, W. Hofmann, for the H.E.S.S. Collaboration","doi":"10.1063/1.3076758","DOIUrl":"https://doi.org/10.1063/1.3076758","url":null,"abstract":"Combining the results of targeted observations, H.E.S.S. has accumulated a large amount of extra‐galactic exposure at TeV energies. Due to its large field of view a considerable part of the sky (0.6 sr) has been observed with high sensitivity outside the targeted observation positions. Since this exposure region contains little inherent bias, it is well suited for studies of extra‐galactic source populations. Given the correlation between ultra‐high energy cosmic rays and nearby extra‐galactic objects recently claimed by the Auger collaboration, this unbiased sky sample by H.E.S.S. is of interest since it includes (besides the targeted sources) 63 AGN within 100 Mpc, for which very‐high energy gamma‐ray flux limits are derived.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81306885","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}
D. Russell, D. Maitra, R. Fender, F. L. U. O. Amsterdam, U. Southampton, Las Cumbres Observatory Global Telescope Network, Open University
Synchrotron emission from jets produced by X-ray binaries can be detected at optical and infrared (IR) frequencies. I show that optical/IR colour-magnitude diagrams of the outbursts of nine X-ray binaries successfully separate thermal disc emission from non-thermal jet emission, in both black hole and neutron star sources. A heated single-temperature blackbody is able to reproduce the observed relations between colour and magnitude, except when excursions are made to a redder colour than expected, which is due to jet emission. The general picture that is developed is then incorporated into the unified picture of disc-jet behaviour in black hole X-ray binaries. At a given position of a source in the X-ray hardness-intensity diagram, the radio, IR and optical properties can be inferred. Similarly, it is possible to predict the X-ray and radio luminosities and spectral states from optical/IR monitoring.
{"title":"Unifying disc-jet behaviour in X-ray binaries: an optical/IR approach","authors":"D. Russell, D. Maitra, R. Fender, F. L. U. O. Amsterdam, U. Southampton, Las Cumbres Observatory Global Telescope Network, Open University","doi":"10.22323/1.062.0002","DOIUrl":"https://doi.org/10.22323/1.062.0002","url":null,"abstract":"Synchrotron emission from jets produced by X-ray binaries can be detected at optical and infrared (IR) frequencies. I show that optical/IR colour-magnitude diagrams of the outbursts of nine X-ray binaries successfully separate thermal disc emission from non-thermal jet emission, in both black hole and neutron star sources. A heated single-temperature blackbody is able to reproduce the observed relations between colour and magnitude, except when excursions are made to a redder colour than expected, which is due to jet emission. The general picture that is developed is then incorporated into the unified picture of disc-jet behaviour in black hole X-ray binaries. At a given position of a source in the X-ray hardness-intensity diagram, the radio, IR and optical properties can be inferred. Similarly, it is possible to predict the X-ray and radio luminosities and spectral states from optical/IR monitoring.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91000609","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 ROSAT Galactic wind observations confirm that our Galaxy launches supernova driven Galactic winds with wind speeds of about 150 km/s in the Galactic plane. Galactic winds of this strength are incompatible with current isotropic models for Cosmic Ray transport. In order to reproduce our local CRs in the presence of Galactic winds, charged CRs are required to be much more localized than in the standard isotropic GALPROP models. This requires that anisotropic diffusion is the dominant diffusion mode in the interstellar medium, particularly that the diffusion in the disk and in the halo are different. In addition small scale phenomena such as trapping by molecular cloud complexes and the structure of our local environment might influence the secondary CR production rate and our local CR density gradients. We introduce an anisotropic convection driven transport model (aCDM) which is consistent with the Galactic wind observations by ROSAT. This also explains the large bulge/disk ratio as observed by INTEGRAL. Furthermore such models predict an increase in the $e^+/(e^++e^-)$-fraction as observed by PAMELA and HEAT, if the synchrotron constraints in the 408 MHz and WMAP range are taken into account. No additional contribution from Dark Matter is required. The aCDM is able to explain the absence of a positron annihilation signal from molecular clouds as observed by INTEGRAL by virtue of a mechanism which confines and isotropizes CRs between MCs. We find that the EGRET excess of diffuse $gamma$-rays currently cannot be explained by astrophysical effects in this type of model and that the interpretation of the EGRET excess as Dark Matter annihilation is perfectly consistent with all observational constraints from local CR fluxes and synchrotron radiation.
{"title":"Dark Matter Annihilation in the light of EGRET, HEAT, WMAP, INTEGRAL and ROSAT","authors":"I. Gebauer","doi":"10.22323/1.064.0030","DOIUrl":"https://doi.org/10.22323/1.064.0030","url":null,"abstract":"The ROSAT Galactic wind observations confirm that our Galaxy launches supernova driven Galactic winds with wind speeds of about 150 km/s in the Galactic plane. Galactic winds of this strength are incompatible with current isotropic models for Cosmic Ray transport. In order to reproduce our local CRs in the presence of Galactic winds, charged CRs are required to be much more localized than in the standard isotropic GALPROP models. This requires that anisotropic diffusion is the dominant diffusion mode in the interstellar medium, particularly that the diffusion in the disk and in the halo are different. In addition small scale phenomena such as trapping by molecular cloud complexes and the structure of our local environment might influence the secondary CR production rate and our local CR density gradients. We introduce an anisotropic convection driven transport model (aCDM) which is consistent with the Galactic wind observations by ROSAT. This also explains the large bulge/disk ratio as observed by INTEGRAL. Furthermore such models predict an increase in the $e^+/(e^++e^-)$-fraction as observed by PAMELA and HEAT, if the synchrotron constraints in the 408 MHz and WMAP range are taken into account. No additional contribution from Dark Matter is required. The aCDM is able to explain the absence of a positron annihilation signal from molecular clouds as observed by INTEGRAL by virtue of a mechanism which confines and isotropizes CRs between MCs. We find that the EGRET excess of diffuse $gamma$-rays currently cannot be explained by astrophysical effects in this type of model and that the interpretation of the EGRET excess as Dark Matter annihilation is perfectly consistent with all observational constraints from local CR fluxes and synchrotron radiation.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82360716","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 : 2008-11-17DOI: 10.1051/0004-6361:200809585
J. Eymeren, M. Marcelin, B. Koribalski, R. Dettmar, D. Bomans, J. Gach, P. Balard
Abridged. Context. The metal content of dwarf galaxies and the metal enrichment of the intergalactic medium both suggest that mass loss from galaxies is a significant factor for the chemical evolution history of galaxies, in particular of dwarf galaxies. However, no clear evidence of a blow-away in local dwarf galaxies has been found so far. Aims. We therefore performed a detailed kinematic analysis of the neutral and ionised gas in the nearby star-forming irregular dwarf galaxy NGC 2366 in order to make predictions about the fate of the gas and to get a more complete picture of this galaxy. Methods. A deep Halpha image and Fabry-Perot interferometric data of NGC 2366 were obtained. They were complemented by HI synthesis data from the THINGS survey. We searched for line-splitting both in Halpha and HI by performing a Gaussian decomposition. To get an idea whether the expansion velocities are high enough for a gas blow-away, we used the pseudo-isothermal halo model, which gives us realistic values for the escape velocities of NGC 2366. The good data quality also allowed us to discuss some peculiarities of the morphology and the dynamics in NGC 2366. Results. A large red-shifted outflow north west of the giant extragalactic HII region with an expansion velocity of up to 50 km/s is found in Halpha, but not in HI. Additionally, a blue-shifted component north of the giant extragalactic HII region was detected both in Halpha and HI with an expansion velocity of up to 30 km/s. A comparison with the escape velocities of NGC 2366 reveals that the gas does not have enough kinetic energy to leave the gravitational potential.
{"title":"A kinematic study of the irregular dwarf galaxy NGC 2366 using HI and Halpha observations","authors":"J. Eymeren, M. Marcelin, B. Koribalski, R. Dettmar, D. Bomans, J. Gach, P. Balard","doi":"10.1051/0004-6361:200809585","DOIUrl":"https://doi.org/10.1051/0004-6361:200809585","url":null,"abstract":"Abridged. Context. The metal content of dwarf galaxies and the metal enrichment of the intergalactic medium both suggest that mass loss from galaxies is a significant factor for the chemical evolution history of galaxies, in particular of dwarf galaxies. However, no clear evidence of a blow-away in local dwarf galaxies has been found so far. \u0000Aims. We therefore performed a detailed kinematic analysis of the neutral and ionised gas in the nearby star-forming irregular dwarf galaxy NGC 2366 in order to make predictions about the fate of the gas and to get a more complete picture of this galaxy. \u0000Methods. A deep Halpha image and Fabry-Perot interferometric data of NGC 2366 were obtained. They were complemented by HI synthesis data from the THINGS survey. We searched for line-splitting both in Halpha and HI by performing a Gaussian decomposition. To get an idea whether the expansion velocities are high enough for a gas blow-away, we used the pseudo-isothermal halo model, which gives us realistic values for the escape velocities of NGC 2366. The good data quality also allowed us to discuss some peculiarities of the morphology and the dynamics in NGC 2366. \u0000Results. A large red-shifted outflow north west of the giant extragalactic HII region with an expansion velocity of up to 50 km/s is found in Halpha, but not in HI. Additionally, a blue-shifted component north of the giant extragalactic HII region was detected both in Halpha and HI with an expansion velocity of up to 30 km/s. A comparison with the escape velocities of NGC 2366 reveals that the gas does not have enough kinetic energy to leave the gravitational potential.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77817954","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 appearance and time variability of the accreting millisecond X‐ray pulsars (hereafter AMXPs, e.g. [27]) depends strongly on the accretion rate and the effective viscosity and magnetic diffusivity of the disk‐magnetosphere boundary. The accretion rate is the main parameter which determines the location of the magnetospheric radius of the neutron star. We introduce a classification of accreting neutron stars as a function of the accretion rate and show the corresponding stages obtained from our global 3D magnetohydrodynamic (MHD) simulations and from our axisymmetric MHD simulations. We discuss the expected variability features in these stages of accretion, both periodic and quasi‐periodic (QPOs). We conclude that the periodicity may be suppressed at both very high and very low accretion rates. In addition the periodicity may disappear when ordered funnel flow accretion is replaced by disordered accretion through the interchange instability.
{"title":"Modeling of Disk-Star Interaction: Different Regimes of Accretion and Variability","authors":"M. Romanova, A. Kulkarni, M. Long, R. Lovelace","doi":"10.1063/1.3031210","DOIUrl":"https://doi.org/10.1063/1.3031210","url":null,"abstract":"The appearance and time variability of the accreting millisecond X‐ray pulsars (hereafter AMXPs, e.g. [27]) depends strongly on the accretion rate and the effective viscosity and magnetic diffusivity of the disk‐magnetosphere boundary. The accretion rate is the main parameter which determines the location of the magnetospheric radius of the neutron star. We introduce a classification of accreting neutron stars as a function of the accretion rate and show the corresponding stages obtained from our global 3D magnetohydrodynamic (MHD) simulations and from our axisymmetric MHD simulations. We discuss the expected variability features in these stages of accretion, both periodic and quasi‐periodic (QPOs). We conclude that the periodicity may be suppressed at both very high and very low accretion rates. In addition the periodicity may disappear when ordered funnel flow accretion is replaced by disordered accretion through the interchange instability.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81630977","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 : 2008-11-17DOI: 10.1051/0004-6361/200911625
V. Gurzadyan, A. Allahverdyan, T. Ghahramanyan, A. Kashin, H. Khachatryan, Armen Kocharyan, Armen Kocharyan, H. Kuloghlian, S. Mirzoyan, E. Poghosian, G. Yegorian
A new map of the sky representing the degree of randomness in the cosmic microwave background (CMB) temperature has been obtained. The map based on estimation of the Kolmogorov stochasticity parameter clearly distinguishes the contribution of the Galactic disk from the CMB and reveals regions of various degrees of randomness that can reflect the properties of inhomogeneities in the Universe. For example, among the high randomness regions is the southern non-Gaussian anomaly, the Cold Spot, with a stratification expected for the voids. Existence of its counterpart, a Northern Cold Spot with almost identical randomness properties among other low-temperature regions is revealed. By its informative power, Kolmogorov's map can be complementary to the CMB temperature and polarization sky maps.
{"title":"Kolmogorov cosmic microwave background sky","authors":"V. Gurzadyan, A. Allahverdyan, T. Ghahramanyan, A. Kashin, H. Khachatryan, Armen Kocharyan, Armen Kocharyan, H. Kuloghlian, S. Mirzoyan, E. Poghosian, G. Yegorian","doi":"10.1051/0004-6361/200911625","DOIUrl":"https://doi.org/10.1051/0004-6361/200911625","url":null,"abstract":"A new map of the sky representing the degree of randomness in the cosmic microwave background (CMB) temperature has been obtained. The map based on estimation of the Kolmogorov stochasticity parameter clearly distinguishes the contribution of the Galactic disk from the CMB and reveals regions of various degrees of randomness that can reflect the properties of inhomogeneities in the Universe. For example, among the high randomness regions is the southern non-Gaussian anomaly, the Cold Spot, with a stratification expected for the voids. Existence of its counterpart, a Northern Cold Spot with almost identical randomness properties among other low-temperature regions is revealed. By its informative power, Kolmogorov's map can be complementary to the CMB temperature and polarization sky maps.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82129377","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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