Hasil untuk "astro-ph.EP"

T. Venumadhav, B. Zackay, Javier Roulet et al.

We report the detection of new binary black hole merger events in the publicly available data from the second observing run of advanced LIGO and advanced Virgo (O2). The mergers were discovered using the new search pipeline described in Venumadhav et al. (1902.10341), and are above the detection thresholds as defined in Abbott et al. (1811.12907). Three of the mergers (GW170121, GW170304, GW170727) have inferred probabilities of being of astrophysical origin $p_{\rm astro} > 0.98$. The remaining three (GW170425, GW170202, GW170403) are less certain, with $p_{\rm astro}$ ranging from $0.5$ to $0.8$. The newly found mergers largely share the statistical properties of previously reported events, with the exception of GW170403, the least secure event, which has a highly negative effective spin parameter $\chi_{\rm eff}$. The most secure new event, GW170121 ($p_{\rm astro} > 0.99$), is also notable due to its inferred negative value of $\chi_{\rm eff}$, which is inconsistent with being positive at the $\approx 95.8\%$ confidence level. The new mergers nearly double the sample of gravitational wave events reported from O2, and present a substantial opportunity to explore the statistics of the binary black hole population in the Universe. The increase in volume is larger when the constituent detectors of the network have very different sensitivities, as is likely to be the case in current and future runs.

K. Hayashida, H. Tsunemi, T. Tsuru et al.

Mutiara Hikmah

J. Mwebaze, D. Boxhoorn, J. McFarland et al.

Most often, astronomers are interested in a source (e.g., moving, variable, or extreme in some colour index) that lies on a few pixels of an image. However, the classical approach in astronomical data processing is the processing of the entire image or set of images even when the sole source of interest may exist on only a few pixels of one or a few images. This is because pipelines have been written and designed for instruments with fixed detector properties (e.g., image size, calibration frames, overscan regions, etc.). Furthermore, all metadata and processing parameters are based on an instrument or a detector. Accordingly, out of many thousands of images for a survey, this can lead to unnecessary processing of data that is both time-consuming and wasteful. We describe the architecture and an implementation of sub-image processing in Astro-WISE. The architecture enables a user to select, retrieve and process only the relevant pixels in an image where the source exists. We show that lineage data collected during the processing and analysis of datasets can be reused to perform selective reprocessing (at sub-image level) on datasets while the remainder of the dataset is untouched, a difficult process to automate without lineage.

F. S. Portera, J. Adamsa, G. Brownb et al.

M. Ozaki, Tadayuki Takahashi, M. Kokubun et al.

J. Ali, Jiancheng Fang

Multisensor navigation data synthesis (MNDS) is the process of fusing outputs from inertial sensors with information from other sensors and information processing blocks into one representational form. This technique is anticipated to accomplish enhanced accuracy and more specific inferences than could be achieved by the use of a single sensor alone. Therefore, this research work expounds innovative filtering methodology for the multisensor navigation data synthesis for a ballistic missile application that augments navigation system performance. The premise and characteristics of strapdown inertial navigation system (SINS) integrated with the astronavigation system (ANS) based on the unscented particle filter (UPF) are investigated in this paper. Configuration of the integrated navigation system is presented with its canonical model, and system dynamic and stochastic models required for the filtering algorithm are presented. To exemplify integrated navigation filter mechanization is the foremost aspiration of this research. To validate and corroborate the designed MNDS technique, simulations are carried out that demonstrate the validity of this method on enhancing the navigation system's accuracy with estimation and compensation for the gyro's drift. This integrated system results in a significant reduction in impact-point dispersion of a re-entry vehicle.

H. Klapdor-kleingrothaus, R. Viollier

A. Furuzawa, Y. Ogasaka, H. Kunieda et al.

S. Roberts, C. Harris

A. Davidsen, K. Long, S. Durrance et al.

P. Ochalski, U. N. Frankenstein, E. L. Hertzberg et al.

P. Morrissey, P. Feldman, M. McGrath et al.

R. Wattenbach, K. Moritz

Tadayuki Takahashi, M. Nomachi, Y. Fukazawa et al.

H. Kaneda, Y. Okamura, T. Nakagawa et al.

T. Onaka, N. Fujishiro, Chiaki Ihara et al.

Kai-wing Chan, Y. Soong, P. Serlemitsos

Y. Fujita, Tomoaki Matsumoto, K. Wada et al.

This is the first attempt to construct detailed X-ray spectra of clusters of galaxies from the results of high-resolution hydrodynamic simulations and simulate X-ray observations in order to study velocity fields of the intracluster medium (ICM). The hydrodynamic simulations are based on the recently proposed tsunami model, in which cluster cores are affected by bulk motions of the ICM and turbulence is produced. We note that most other solutions of the cooling flow problem also involve the generation of turbulence in cluster cores. From the mock X-ray observations with the Astro-E2 X-Ray Spectrometer, we find that turbulent motion of the ICM in cluster cores could be detected with the satellite. The Doppler shifts of the metal lines could be used to discriminate among turbulence models. The gas velocities measured through the mock observations are consistent with the line emission weighted values inferred directly from hydrodynamic simulations.

H. Nakajima, H. Yamaguchi, H. Matsumoto et al.