The Experts below are selected from a list of 205794 Experts worldwide ranked by ideXlab platform

Michael J. Reece - One of the best experts on this subject based on the ideXlab platform.

P Das - One of the best experts on this subject based on the ideXlab platform.

  • counter dispersed slitless Spectroscopy Technique planetary nebula velocities in the halo of ngc 1399
    arXiv: Cosmology and Nongalactic Astrophysics, 2010
    Co-Authors: Emily Mcneil, Magda Arnaboldi, K C Freeman, Ortwin Gerhard, L Coccato, P Das
    Abstract:

    Using a counter-dispersed slitless Spectroscopy Technique, we detect and measure the line-of-sight velocities of 187 planetary nebulae (PNe) around one of the nearest cD galaxies, NGC 1399, with FORS1 on the VLT. We describe the method for identifying and classifying the emission-line sources and the procedure for computing their J2000 coordinates and velocities. The number of PN detections and the errors in the velocity measurements (37 km/s indicate that this Technique is comparable to other methods, such as that described by Teodorescu et al. (2005). We present the spatial distribution of the PNe and a basic analysis of their velocities. The PN two-dimensional velocity field shows marginal rotation consistent with other studies. We also find a low-velocity substructure in the halo and a flatter velocity-dispersion profile compared to previous observations that extends to ~400 arcsec. The detection of a low-velocity subcomponent underscores the importance of discrete velocity tracers for the detection of un-mixed components. The new velocity-dispersion profile is in good agreement with revised velocity dispersions for the red globular clusters in NGC 1399, using the data of Schuberth et al. (2009). The outer parts of this profile are consistent with one of the dynamical models of Kronawitter et al. (2000), which corresponds to a circular velocity of ~340 km/s and a rescaled B-band mass-to-light ratio of ~20 at 7' radius. These measurements trace the kinematics of the outer halo and disentangle the heterogenous populations in the Fornax Cluster core. The new data set the stage for a revised dynamical model of the outer halo of NGC 1399.

  • counter dispersed slitless Spectroscopy Technique planetary nebula velocities in the halo of ngc 1399
    Astronomy and Astrophysics, 2010
    Co-Authors: Emily Mcneil, Magda Arnaboldi, K C Freeman, Ortwin Gerhard, L Coccato, P Das
    Abstract:

    Aims. Using a counter-dispersed slitless Spectroscopy Technique, we detect and measure the line-of-sight velocities of 187 planetary nebulae (PNe) around one of the nearest cD galaxies, NGC 1399, with FORS1 on the VLT. Methods. We describe the method for identifying and classifying the emission-line sources and the procedure for computing their J2000 coordinates and velocities. The number of PN detections and the errors in the velocity measurements (37 km s −1 ) indicate that this Technique is comparable to other methods. Results. We present the spatial distribution of the PNe and a basic analysis of their velocities. The PN two-dimensional velocity field shows marginal rotation consistent with other studies. We also find a low-velocity substructure in the halo and a flatter velocity-dispersion profile compared to previous observations that extends to ∼400 �� . The detection of a low-velocity subcomponent underscores the importance of discrete velocity tracers for the detection of un-mixed components. Conclusions. The new velocity-dispersion profile is in good agreement with revised velocity dispersions for the red globular clusters in NGC 1399. The outer parts of this profile are consistent with one of the dynamical models, which corresponds to a circular velocity of � 340 kms −1 and a rescaled B-band mass-to-light ratio of � 20 at 7 � radius. These measurements trace the kinematics of the outer halo and disentangle the heterogenous populations in the Fornax Cluster core. The new data set the stage for a revised dynamical model of the outer halo of NGC 1399.

T. Jean Daou - One of the best experts on this subject based on the ideXlab platform.

  • Facile and fast determination of Si/Al ratio of zeolites using FTIR Spectroscopy Technique
    Microporous and Mesoporous Materials, 2021
    Co-Authors: Severinne Rigolet, Laure Michelin, Jean-louis Paillaud, Svetlana Mintova, Fitri Khoerunnisa, T. Jean Daou
    Abstract:

    A fast and simple quantitative determination of the Si/Al ratio (SAR) in zeolite frameworks using IR Spectroscopy is reported. From the linear regression analysis, the Si/Al ratios correlate linearly to the corresponding wavenumbers (970-1090 cm-1) for the medium-to-high Al content zeolites (1 < SAR < 5). The accuracy and validity of the IR model is also exemplified for 19 zeolites with different SAR and framework topologies. The quantitative determination of the SAR by the developed approach is shown to be an alternative Technique to conventional ICP-OES and XRF Spectroscopy Techniques.

H Abele - One of the best experts on this subject based on the ideXlab platform.

  • realization of a gravity resonance Spectroscopy Technique
    Nature Physics, 2011
    Co-Authors: Tobias Jenke, P Geltenbort, Hartmut Lemmel, H Abele
    Abstract:

    Spectroscopic Techniques are mostly used to study the interaction between matter and electromagnetic fields. Here, an experiment that probes the transitions between quantum states of neutrons in the Earth’s gravitational field demonstrates an exotic variant of Spectroscopy, and one that might lead to sensitive fundamental tests of gravity laws.

Nan Meng - One of the best experts on this subject based on the ideXlab platform.