Masato Kagitani

Bio: Masato Kagitani is an academic researcher from Tohoku University. The author has contributed to research in topics: Jupiter & Linear polarization. The author has an hindex of 19, co-authored 83 publications receiving 1274 citations.

Primary Black Hole Spin in OJ 287 as Determined by the General Relativity Centenary Flare

Abstract: OJ 287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts that are predictable in a binary black hole model. The model predicted a major optical outburst in 2015 December. We found that the outburst did occur within the expected time range, peaking on 2015 December 5 at magnitude 12.9 in the optical R-band. Based on Swift/XRT satellite measurements and optical polarization data, we find that it included a major thermal component. Its timing provides an accurate estimate for the spin of the primary black hole, $\chi =0.313\pm 0.01$. The present outburst also confirms the established general relativistic properties of the system such as the loss of orbital energy to gravitational radiation at the 2% accuracy level, and it opens up the possibility of testing the black hole no-hair theorem with 10% accuracy during the present decade.

Primary black hole spin in OJ287 as determined by the General Relativity centenary flare

Abstract: OJ287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts which are predictable in a binary black hole model. The model predicted a major optical outburst in December 2015. We found that the outburst did occur within the expected time range, peaking on 2015 December 5 at magnitude 12.9 in the optical R-band. Based on Swift/XRT satellite measurements and optical polarization data, we find that it included a major thermal component. Its timing provides an accurate estimate for the spin of the primary black hole, chi = 0.313 +- 0.01. The present outburst also confirms the established general relativistic properties of the system such as the loss of orbital energy to gravitational radiation at the 2 % accuracy level and it opens up the possibility of testing the black hole no-hair theorem with a 10 % accuracy during the present decade.

Extreme Ultraviolet Radiation Measurement for Planetary Atmospheres/Magnetospheres from the Earth-Orbiting Spacecraft (Extreme Ultraviolet Spectroscope for Exospheric Dynamics: EXCEED)

Abstract: The Sprint-A satellite with the EUV spectrometer (Extreme Ultraviolet Spectroscope for Exospheric Dynamics: EXCEED) was launched in September 2013 by the Epsilon rocket. Now it is orbiting around the Earth (954.05 km×1156.87 km orbit; the period is 104 minutes) and one has started a broad and varied observation program. With an effective area of more than 1 cm2 and well-calibrated sensitivity in space, the EUV spectrometer will produce spectral images (520–1480 A) of the atmospheres/magnetospheres of several planets (Mercury, Venus, Mars, Jupiter, and Saturn) from the Earth’s orbit. At the first day of the observation, EUV emissions from the Io plasma torus (mainly sulfur ions) and aurora (H2 Lyman and Werner bands) of Jupiter have been identified. Continuous 3-month measurement for Io’s plasma torus and aurora is planned to witness the sporadic and sudden brightening events occurring on one or both regions. For Venus, the Fourth Positive (A1 Π-X1 Σ +) system of CO and some yet known emissions of the atmosphere were identified even though the exposure was short (8-min). Long-term exposure from April to June (for approximately 2 months) will visualize the Venusian ionosphere and tail in the EUV spectral range. Saturn and Mars are the next targets.

Authenticating the presence of a relativistic massive black hole binary in OJ 287 using its general relativity centenary flare: improved orbital parameters

Abstract: Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadrupolar order. It turns out that even the effects of certain hereditary contributions to GW emission are required to predict impact flare timings of OJ 287. We develop an approach that incorporates this effect into the BBH model for OJ 287. This allows us to demonstrate an excellent agreement between the observed impact flare timings and those predicted from ten orbital cycles of the BBH central engine model. The deduced rate of orbital period decay is nine orders of magnitude higher than the observed rate in PSR 1913+16, demonstrating again the relativistic nature of OJ 287's central engine. Finally, we argue that precise timing of the predicted 2019 impact flare should allow a test of the celebrated black hole "no-hair theorem" at the 10% level.

Stochastic Modeling of Multiwavelength Variability of the Classical BL Lac Object OJ 287 on Timescales Ranging from Decades to Hours

Abstract: A.G. and M.O. acknowledge support from the Polish National Science Centre (NCN) through the grant 2012/04/A/ST9/00083. D.K.W. and A.G. acknowledge the support from 2013/09/B/ST9/00026. L.S. and V.M. are supported by Polish NSC grant UMO-2016/22/E/ST9/00061. M.S. acknowledges the support of 2012/07/B/ST9/04404. S.Z. acknowledges the support of 2013/09/B/ST9/00599 and 2017/27/B/ST9/01855. R.H. acknowledges GA CR grant 13-33324S. A.S. and M.So. were supported by National Aeronautics and Space Administration (NASA) contract NAS8-03060 (Chandra X-ray Center). M.So. also acknowledges Polish NCN grant OPUS 2014/13/B/ST9/00570. A. V.F. is grateful for support from National Science Foundation (NSF) grant AST-1211916, NASA grant NNX12AF12G, the TABASGO Foundation, the Christopher R. Redlich Fund, and the Miller Institute for Basic Research in Science (U.C. Berkeley). Research at Lick Observatory is partially supported by a generous gift from Google.This research has made use of data from the University of Michigan Radio Astronomy Observatory, which has been supported by the University of Michigan and by a series of grants from the NSF, most recently AST-0607523, and NASA Fermi grants NNX09AU16G, NNX10AP16G, and NNX11A013G. The OVRO 40 m Telescope Fermi Blazar Monitoring Program is supported by NASA under awards NNX08AW31G and NNX11A043G, and by the NSF under awards AST-0808050 and AST-1109911. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller University.The Fermi-LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include NASA and the Department of Energy (DOE) in the United States, the Commissariat a l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucleaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK), and Japan Aerospace Exploration Agency (JAXA) in Japan, and the KA Wallenberg Foundation, the Swedish Research Council, and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d'Etudes Spatiales in France. This work was performed in part under DOE Contract DE-AC02-765F00515. (2012/04/A/ST9/00083 - Polish National Science Centre (NCN); UMO-2016/22/E/ST9/00061 - Polish NSC grant; 13-33324S - GA CR; NAS8-03060 - National Aeronautics and Space Administration (NASA); OPUS 2014/13/B/ST9/00570 - Polish NCN grant; AST-1211916 - National Science Foundation (NSF) grant; NNX12AF12G - NASA grant; TABASGO Foundation; Christopher R. Redlich Fund; Miller Institute for Basic Research in Science (U.C. Berkeley); Google; University of Michigan; AST-0607523 - NSF; AST-0808050 - NSF; AST-1109911 - NSF; NNX09AU16G - NASA Fermi grants; NNX10AP16G - NASA Fermi grants; NNX11A013G - NASA Fermi grants; NNX08AW31G - NASA; NNX11A043G - NASA; NASA; Department of Energy (DOE) in the United States; Commissariat a l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucleaire et de Physique des Particules in France; Agenzia Spaziale Italiana; Istituto Nazionale di Fisica Nucleare in Italy; Ministry of Education, Culture, Sports, Science and Technology (MEXT); High Energy Accelerator Research Organization (KEK); Japan Aerospace Exploration Agency (JAXA) in Japan; KA Wallenberg Foundation; Swedish Research Council; Swedish National Space Board in Sweden; Istituto Nazionale di Astrofisica in Italy; Centre National d'Etudes Spatiales in France; DE-AC02-765F00515 - DOE Contract; 2013/09/B/ST9/00026; 2012/07/B/ST9/04404; 2013/09/B/ST9/00599; 2017/27/B/ST9/01855)

Parameter estimation in astronomy through application of the likelihood ratio. [satellite data analysis techniques

Abstract: Many problems in the experimental estimation of parameters for models can be solved through use of the likelihood ratio test. Applications of the likelihood ratio, with particular attention to photon counting experiments, are discussed. The procedures presented solve a greater range of problems than those currently in use, yet are no more difficult to apply. The procedures are proved analytically, and examples from current problems in astronomy are discussed.

Radiative Processes In Astrophysics

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Imaging Extrasolar Giant Planets

Abstract: High-contrast adaptive optics imaging is a powerful technique to probe the architectures of planetary systems from the outside-in and survey the atmospheres of self-luminous giant planets. Direct imaging has rapidly matured over the past decade and especially the last few years with the advent of high-order adaptive optics systems, dedicated planet-finding instruments with specialized coronagraphs, and innovative observing and post-processing strategies to suppress speckle noise. This review summarizes recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments. I conclude with a statistical meta-analysis of deep imaging surveys in the literature. Based on observations of 384 unique and single young ($\approx$5--300~Myr) stars spanning stellar masses between 0.1--3.0~\Msun, the overall occurrence rate of 5--13~\Mjup \ companions at orbital distances of 30--300~AU is 0.6$^{+0.7}_{-0.5}$\% assuming hot-start evolutionary models. The most massive giant planets regularly accessible to direct imaging are about as rare as hot Jupiters are around Sun-like stars. Dividing this sample into individual stellar mass bins does not reveal any statistically-significant trend in planet frequency with host mass: giant planets are found around 2.8$^{+3.7}_{-2.3}$\% of BA stars, $<$4.1\% of FGK stars, and $<$3.9\% of M dwarfs. Looking forward, extreme adaptive optics systems and the next generation of ground- and space-based telescopes with smaller inner working angles and deeper detection limits will increase the pace of discovery to ultimately map the demographics, composition, evolution, and origin of planets spanning a broad range of masses and ages.

The Space Physics Environment Data Analysis System (SPEDAS)

Abstract: With the advent of the Heliophysics/Geospace System Observatory (H/GSO), a complement of multi-spacecraft missions and ground-based observatories to study the space environment, data retrieval, analysis, and visualization of space physics data can be daunting. The Space Physics Environment Data Analysis System (SPEDAS), a grass-roots software development platform ( www.spedas.org ), is now officially supported by NASA Heliophysics as part of its data environment infrastructure. It serves more than a dozen space missions and ground observatories and can integrate the full complement of past and upcoming space physics missions with minimal resources, following clear, simple, and well-proven guidelines. Free, modular and configurable to the needs of individual missions, it works in both command-line (ideal for experienced users) and Graphical User Interface (GUI) mode (reducing the learning curve for first-time users). Both options have “crib-sheets,” user-command sequences in ASCII format that can facilitate record-and-repeat actions, especially for complex operations and plotting. Crib-sheets enhance scientific interactions, as users can move rapidly and accurately from exchanges of technical information on data processing to efficient discussions regarding data interpretation and science. SPEDAS can readily query and ingest all International Solar Terrestrial Physics (ISTP)-compatible products from the Space Physics Data Facility (SPDF), enabling access to a vast collection of historic and current mission data. The planned incorporation of Heliophysics Application Programmer’s Interface (HAPI) standards will facilitate data ingestion from distributed datasets that adhere to these standards. Although SPEDAS is currently Interactive Data Language (IDL)-based (and interfaces to Java-based tools such as Autoplot), efforts are under-way to expand it further to work with python (first as an interface tool and potentially even receiving an under-the-hood replacement). We review the SPEDAS development history, goals, and current implementation. We explain its “modes of use” with examples geared for users and outline its technical implementation and requirements with software developers in mind. We also describe SPEDAS personnel and software management, interfaces with other organizations, resources and support structure available to the community, and future development plans.