The Experts below are selected from a list of 53151 Experts worldwide ranked by ideXlab platform
H. Matsumoto - One of the best experts on this subject based on the ideXlab platform.
-
A Detailed Study of Non-thermal X-Ray Properties and Interstellar Gas toward the γ-Ray Supernova Remnant RX J1713.7-3946
The Astrophysical Journal, 2015Co-Authors: H. Sano, T. Fukuda, S. Yoshiike, J. Sato, H. Horachi, T. Kuwahara, K. Torii, T. Hayakawa, T. Tanaka, H. MatsumotoAbstract:We have carried out a spectral analysis of the Suzaku X-ray data in the 0.4-12 keV range toward the shell-type very high-energy γ-ray supernova remnant (SNR) RX J1713.7–3946. The aims of this analysis are to estimate detailed X-rays spectral properties at a high angular resolution up to 2 arcmin and to compare them with the Interstellar Gas. The X-ray spectrum is non-thermal and used to calculate absorbing column density, photon index, and absorption-corrected X-ray flux. The photon index varies significantly from 2.1 to 2.9. It is shown that the X-ray intensity is well correlated with the photon index, especially in the west region, with a correlation coefficient of 0.81. The X-ray intensity tends to increase with the averaged Interstellar Gas density while the dispersion is relatively large. The hardest spectra, with photon indexes of less than 2.4, are found outside of the central 10 arcmin of the SNR, from the north to the southeast (~430 arcmin2) and from the southwest to the northwest (~150 arcmin2). The former region shows low Interstellar Gas density, while the latter shows high Interstellar Gas density. We present a discussion of possible scenarios that explain the distribution of the photon index and its relationship with the Interstellar Gas.
-
A detailed study of non-thermal X-ray properties and Interstellar Gas toward the $\gamma$-ray supernova remnant RX J1713.7-3946
Astrophys.J., 2015Co-Authors: H. Sano, T. Fukuda, S. Yoshiike, J. Sato, H. Horachi, T. Kuwahara, K. Torii, T. Hayakawa, T. Tanaka, H. MatsumotoAbstract:We have carried out a spectral analysis of the Suzaku X-ray data in the 0.4-12 keV range toward the shell-type very high-energy γ-ray supernova remnant (SNR) RX J1713.7–3946. The aims of this analysis are to estimate detailed X-rays spectral properties at a high angular resolution up to 2 arcmin and to compare them with the Interstellar Gas. The X-ray spectrum is non-thermal and used to calculate absorbing column density, photon index, and absorption-corrected X-ray flux. The photon index varies significantly from 2.1 to 2.9. It is shown that the X-ray intensity is well correlated with the photon index, especially in the west region, with a correlation coefficient of 0.81. The X-ray intensity tends to increase with the averaged Interstellar Gas density while the dispersion is relatively large. The hardest spectra, with photon indexes of less than 2.4, are found outside of the central 10 arcmin of the SNR, from the north to the southeast (~430 arcmin(2)) and from the southwest to the northwest (~150 arcmin(2)). The former region shows low Interstellar Gas density, while the latter shows high Interstellar Gas density. We present a discussion of possible scenarios that explain the distribution of the photon index and its relationship with the Interstellar Gas.
Eberhard Möbius - One of the best experts on this subject based on the ideXlab platform.
-
Diagnosing the Neutral Interstellar Gas Flow at 1 AU with IBEX-Lo
Space Science Reviews, 2009Co-Authors: Eberhard Möbius, Maciej Bzowski, Harald Kucharek, George Clark, Morgan E O'neill, L. Petersen, L. Saul, Peter Wurz, Stephen A. Fuselier, Vladislav V. IzmodenovAbstract:Every year in fall and spring the Interstellar Boundary Explorer (IBEX) will observe directly the Interstellar Gas flow at 1 AU over periods of several months. The IBEX-Lo sensor employs a powerful triple time-of-flight mass spectrometer. It can distinguish and image the O and He flow distributions in the northern fall and spring, making use of sensor viewing perpendicular to the Sun-pointing spin axis. To effectively image the narrow flow distributions IBEX-Lo has a high angular resolution quadrant in its collimator. This quadrant is employed selectively for the Interstellar Gas flow viewing in the spring by electrostatically shutting off the remainder of the aperture. The operational scenarios, the expected data, and the necessary modeling to extract the Interstellar parameters and the conditions in the heliospheric boundary are described.
-
Heliospheric conditions that affect the Interstellar Gas inside the heliosphere
Astronomy & Astrophysics, 2004Co-Authors: D. R. Mcmullin, Maciej Bzowski, Eberhard Möbius, A. Pauluhn, Ruth M. Skoug, William T. Thompson, Manfred Witte, R. Von Steiger, Daniel Rucinski, Darrell L. JudgeAbstract:The Interstellar Gas that flows through the heliosphere is strongly affected by ionization close to the Sun, in particular solar photoionization, electron impact, and charge exchange. Therefore, the interpretation of any observation of Interstellar Gas in the inner heliosphere hinges upon the accurate knowledge of these effects and their variations. In addition, the irradiance and line profile of the relevant solar spectral line are needed to properly interpret resonant backscattering observations of the Interstellar neutral Gas. With instrumentation on ACE, SOHO and Wind, continuous monitoring of these important environmental conditions simultaneously with a multitude of Interstellar Gas observations has become possible for the first time. In this paper we present a compilation of the processes and parameters that affect the distribution of Interstellar helium inside the heliosphere and their observation, including the irradiance and line profile of the He 58.4 nm line. We also make the connection to proxies for these parameters and evaluate their accuracy in order to expand the time period of coverage wherever possible.
-
Coordinated observation of local Interstellar helium in the Heliosphere Heliospheric conditions that affect the Interstellar Gas inside the heliosphere
2004Co-Authors: D. R. Mcmullin, Eberhard Möbius, A. Pauluhn, William T. Thompson, Manfred Witte, R. Von Steiger, Darrell L. Judge, M. Banaszkiewicz, Rosine LallementAbstract:The Interstellar Gas that flows through the heliosphere is strongly affected by ionization close to the Sun, in particular solar photoionization, electron impact, and charge exchange. Therefore, the interpretation of any observation of Interstellar Gas in the inner heliosphere hinges upon the accurate knowledge of these effects and their variations. In addition, the irradiance and line profile of the relevant solar spectral line are needed to properly interpret resonant backscattering observations of the inter- stellar neutral Gas. With instrumentation on ACE, SOHO and Wind, continuous monitoring of these important environmental conditions simultaneously with a multitude of Interstellar Gas observations has become possible for the first time. In this paper we present a compilation of the processes and parameters that affect the distribution of Interstellar helium inside the heliosphere and their observation, including the irradiance and line profile of the He 58.4 nm line. We also make the connection to proxies for these parameters and evaluate their accuracy in order to expand the time period of coverage wherever possible.
-
Direct evidence of the Interstellar Gas flow velocity in the pickup ion cut-off as observed with SOHO CELIAS CTOF
Geophysical Research Letters, 1999Co-Authors: Eberhard Möbius, Darrell L. Judge, Y. Litvinenko, H. Grüwaldt, M. R. Aellig, A. T. Bogdanov, F. M. Ipavich, Peter Bochsler, Martin Hilchenbach, Berndt KleckerAbstract:He+ pickup ions as observed with SOHO CELIAS CTOF have been analyzed for the time period DOY 160–190, 1996. During this time of the year the Earth is on the upwind side of the Interstellar Gas flow with respect to the sun. The high-speed cut-off in the frame of the sun is significantly higher v/Vsw = 2, predicted for pickup ions. The difference increases with lower solar wind speeds. This behavior is interpreted as an effect of the local Interstellar Gas flow velocity (inflow at large distances including gravitational acceleration by the sun) on the pickup ion distribution. The neutral velocity is added to the solar wind velocity in the determination of the pickup ion cut-off on the upwind side and subtracted on the downwind side of the Gas flow. This new observation will provide a valuable tool to determine the Interstellar Gas flow and will thus complement direct neutral Gas measurements.
Vladislav V. Izmodenov - One of the best experts on this subject based on the ideXlab platform.
-
Diagnosing the Neutral Interstellar Gas Flow at 1 AU with IBEX-Lo
Space Science Reviews, 2009Co-Authors: E. Möbius, Harald Kucharek, George Clark, L. Petersen, L. Saul, Peter Wurz, Stephen A. Fuselier, M. O’neill, M. Bzowski, Vladislav V. IzmodenovAbstract:Every year in fall and spring the Interstellar Boundary Explorer (IBEX) will observe directly the Interstellar Gas flow at 1 AU over periods of several months. The IBEX-Lo sensor employs a powerful triple time-of-flight mass spectrometer. It can distinguish and image the O and He flow distributions in the northern fall and spring, making use of sensor viewing perpendicular to the Sun-pointing spin axis. To effectively image the narrow flow distributions IBEX-Lo has a high angular resolution quadrant in its collimator. This quadrant is employed selectively for the Interstellar Gas flow viewing in the spring by electrostatically shutting off the remainder of the aperture. The operational scenarios, the expected data, and the necessary modeling to extract the Interstellar parameters and the conditions in the heliospheric boundary are described. The combination of two key Interstellar species will facilitate a direct comparison of the pristine Interstellar flow, represented by He, which has not been altered in the heliospheric boundary region, with a flow that is processed in the outer heliosheath, represented by O. The O flow distribution consists of a depleted pristine component and decelerated and heated neutrals. Extracting the latter so-called secondary component of Interstellar neutrals will provide quantitative constraints for several important parameters of the heliosheath interaction in current global heliospheric models. Finding the fraction and width of the secondary component yields an independent value for the global filtration factor of species, such as O and H. Thus far filtration can only be inferred, barring observations in the local Interstellar cloud proper. The direction of the secondary component will provide independent information on the Interstellar magnetic field strength and orientation, which has been inferred from SOHO SWAN Ly- α backscattering observations and the two Voyager crossings of the termination shock.
-
Diagnosing the Neutral Interstellar Gas Flow at 1 AU with IBEX-Lo
Space Science Reviews, 2009Co-Authors: Eberhard Möbius, Maciej Bzowski, Harald Kucharek, George Clark, Morgan E O'neill, L. Petersen, L. Saul, Peter Wurz, Stephen A. Fuselier, Vladislav V. IzmodenovAbstract:Every year in fall and spring the Interstellar Boundary Explorer (IBEX) will observe directly the Interstellar Gas flow at 1 AU over periods of several months. The IBEX-Lo sensor employs a powerful triple time-of-flight mass spectrometer. It can distinguish and image the O and He flow distributions in the northern fall and spring, making use of sensor viewing perpendicular to the Sun-pointing spin axis. To effectively image the narrow flow distributions IBEX-Lo has a high angular resolution quadrant in its collimator. This quadrant is employed selectively for the Interstellar Gas flow viewing in the spring by electrostatically shutting off the remainder of the aperture. The operational scenarios, the expected data, and the necessary modeling to extract the Interstellar parameters and the conditions in the heliospheric boundary are described.
H. Sano - One of the best experts on this subject based on the ideXlab platform.
-
Interstellar Gas in the middle-aged SNRs
2017Co-Authors: S. Yoshiike, H. Sano, T. Fukuda, Yasuo FukuiAbstract:An analysis of neutral Interstellar Gas in the γ-ray middle-aged supernova remnants (SNRs) is presented. We carried out multi-line CO observations of 12CO(J = 1–0) and 12CO(J = 2–1) toward three middle-aged SNRs, W44, IC 443 and W28, with the NANTEN2 telescope. For all three SNRs, we identified the shocked molecular Gas which has high-velocity wing emission and the high 12CO J = 2–1/1–0 line intensity ratio of greater than 1. The distribution of these shocked Gas has the good correlation with that of GeV–TeV γ-rays, which indicates these γ-rays originate from hadronic process and the interaction between SNR shock and clouds plays an major role in the cosmic-ray acceleration for these SNRs. By combining CO results with archive H I data, we derived the amount of total Interstellar protons responsible for the γ-rays. Every SNRs have the averaged proton densities ranged from a few hundred to less than 103 cm−3 and we estimated the total cosmic-ray proton energy to be ∼ 1048–1049 erg as lower limits.
-
A Detailed Study of Non-thermal X-Ray Properties and Interstellar Gas toward the γ-Ray Supernova Remnant RX J1713.7-3946
The Astrophysical Journal, 2015Co-Authors: H. Sano, T. Fukuda, S. Yoshiike, J. Sato, H. Horachi, T. Kuwahara, K. Torii, T. Hayakawa, T. Tanaka, H. MatsumotoAbstract:We have carried out a spectral analysis of the Suzaku X-ray data in the 0.4-12 keV range toward the shell-type very high-energy γ-ray supernova remnant (SNR) RX J1713.7–3946. The aims of this analysis are to estimate detailed X-rays spectral properties at a high angular resolution up to 2 arcmin and to compare them with the Interstellar Gas. The X-ray spectrum is non-thermal and used to calculate absorbing column density, photon index, and absorption-corrected X-ray flux. The photon index varies significantly from 2.1 to 2.9. It is shown that the X-ray intensity is well correlated with the photon index, especially in the west region, with a correlation coefficient of 0.81. The X-ray intensity tends to increase with the averaged Interstellar Gas density while the dispersion is relatively large. The hardest spectra, with photon indexes of less than 2.4, are found outside of the central 10 arcmin of the SNR, from the north to the southeast (~430 arcmin2) and from the southwest to the northwest (~150 arcmin2). The former region shows low Interstellar Gas density, while the latter shows high Interstellar Gas density. We present a discussion of possible scenarios that explain the distribution of the photon index and its relationship with the Interstellar Gas.
-
A detailed study of non-thermal X-ray properties and Interstellar Gas toward the $\gamma$-ray supernova remnant RX J1713.7-3946
Astrophys.J., 2015Co-Authors: H. Sano, T. Fukuda, S. Yoshiike, J. Sato, H. Horachi, T. Kuwahara, K. Torii, T. Hayakawa, T. Tanaka, H. MatsumotoAbstract:We have carried out a spectral analysis of the Suzaku X-ray data in the 0.4-12 keV range toward the shell-type very high-energy γ-ray supernova remnant (SNR) RX J1713.7–3946. The aims of this analysis are to estimate detailed X-rays spectral properties at a high angular resolution up to 2 arcmin and to compare them with the Interstellar Gas. The X-ray spectrum is non-thermal and used to calculate absorbing column density, photon index, and absorption-corrected X-ray flux. The photon index varies significantly from 2.1 to 2.9. It is shown that the X-ray intensity is well correlated with the photon index, especially in the west region, with a correlation coefficient of 0.81. The X-ray intensity tends to increase with the averaged Interstellar Gas density while the dispersion is relatively large. The hardest spectra, with photon indexes of less than 2.4, are found outside of the central 10 arcmin of the SNR, from the north to the southeast (~430 arcmin(2)) and from the southwest to the northwest (~150 arcmin(2)). The former region shows low Interstellar Gas density, while the latter shows high Interstellar Gas density. We present a discussion of possible scenarios that explain the distribution of the photon index and its relationship with the Interstellar Gas.
Joseph Silk - One of the best experts on this subject based on the ideXlab platform.
-
The Polytropic Equation of State of Interstellar Gas Clouds
The Astrophysical Journal, 2000Co-Authors: Marco Spaans, Joseph SilkAbstract:Models are presented for the polytropic equation of state of self-gravitating, quiescent Interstellar Gas clouds. A detailed analysis, including chemistry, thermal balance, and radiative transfer, is performed for the physical state of the Gas as a function of density, metallicity, velocity field, and background radiation field. We find that the stiffness of the equation of state strongly depends on all of these physical parameters, and the adiabatic index varies between ~0.2-1.4. The implications for star formation, in particular at high redshift and in starburst galaxies, and the initial stellar mass function are discussed.
-
the polytropic equation of state of Interstellar Gas clouds
arXiv: Astrophysics, 2000Co-Authors: Marco Spaans, Joseph SilkAbstract:Models are presented for the polytropic equation of state of self-gravitating, quiescent Interstellar Gas clouds. A detailed analysis, including chemistry, thermal balance, and radiative transfer, is performed for the physical state of the Gas as a function of density, metallicity, velocity field, and background radiation field. It is found that the stiffness of the equation of state strongly depends on all these physical parameters, and the adiabatic index varies between 0.2-1.4. The implications for star formation, in particular at high redshift and in starburst galaxies, and the initial stellar mass function are discussed.
