Mutsumi Sugizaki

Bio: Mutsumi Sugizaki is an academic researcher from Tokyo Institute of Technology. The author has contributed to research in topics: Luminosity & Pulsar. The author has an hindex of 29, co-authored 133 publications receiving 3463 citations.

The MAXI Mission on the ISS: Science and Instruments for Monitoring All-Sky X-Ray Images

Abstract: The Monitor of All-sky X-ray Image (MAXI) mission is the first astronomical payload to be installed on the Japanese Experiment Module — Exposed Facility (JEM-EF or Kibo-EF) on the International Space Station. It has two types of X-ray slit cameras with wide FOVs and two kinds of X-ray detectors consisting of gas proportional counters covering the energy range of 2 to 30 keV and X-ray CCDs covering the energy range of 0.5 to 12 keV. MAXI will be more powerful than any previous X-ray All Sky Monitor payloads, being able to monitor hundreds of Active Galactic Nuclei. A realistic simulation under optimal observation conditions suggests that MAXI will provide all-sky images of X-ray sources of � 20 mCrab (� 7 � 10 � 10 erg cm � 2 s � 1 in the energy band of 2–30 keV) from observations during one ISS orbit (90 min), � 4.5 mCrab for one day, and � 2 mCrab for one week. The final detectability of MAXI could be � 0.2 mCrab for two years, which is comparable to the source confusion limit of the MAXI field of view (FOV). The MAXI objectives are: (1) to alert the community to X-ray novae and transient X-ray sources, (2) to monitor long-term variabilities of X-ray sources, (3) to stimulate multi-wavelength observations of variable objects, (4) to create unbiased X-ray source cataloges, and (5) to observe diffuse cosmic X-ray emissions, especially with better energy resolution for soft X-rays down to 0.5 keV.

The MAXI Mission on the ISS: Science and Instruments for Monitoring All Sky X-Ray Images

Abstract: The MAXI (Monitor of All-sky X-ray Image) mission is the first astronomical payload to be installed on the Japanese Experiment Module-Exposed Facility (JEM-EF) on the ISS. It is scheduled for launch in the middle of 2009 to monitor all-sky X-ray objects on every ISS orbit. MAXI will be more powerful than any previous X-ray All Sky Monitor (ASM) payloads, being able to monitor hundreds of AGN. MAXI will provide all sky images of X-ray sources of about 20 mCrab in the energy band of 2-30 keV from observation on one ISS orbit (90 min), about 4.5 mCrab for one day, and about 1 mCrab for one month. A final detectability of MAXI could be 0.2 mCrab for 2 year observations.

Discovery of Non-Thermal X-Rays from the Northwest Shell of the New SNR RX J1713.7-3946: The Second SN 1006?

Abstract: We report on the ASCA results of a featureless X-ray spectrum from RX J1713.7—3946, a new shell-like SNR discovered with the ROSAT all-sky survey. The northwest part of RX J1713.7-3946 was in the field of the ASCA Galactic Plane Survey Project, and was found to exhibit a shell-like structure. The spectrum, however, shows neither line emission nor any signature of a thermal origin. Instead, a power-law model with a photon index of 2.4-2.5 gives a reasonable fit to the spectrum, suggesting a non-thermal origin. Together with the similarity to SN 1006, we propose that RX J1713.7—3946 is the second example, after SN 1006, of synchrotron X-ray radiation from a shell of SNRs. Since the synchrotron X-rays suggest the existence of extremely high energy charged particles in the SNR shell, our discovery should have a strong impact on the origin of cosmic X-rays.

Gas Slit Camera (GSC) onboard MAXI on ISS

Abstract: The Gas Slit Camera (GSC) is an X-ray instrument on the MAXI (Monitor of All-sky X-ray Image) mission on the International Space Station. It is designed to scan the entire sky every 92-minute orbital period in the 2‐30 keV band and to achieve the highest sensitivity among the X-ray all-sky monitors ever flown so far. The GSC employs large-area position-sensitive proportional counters with the total detector area of 5350 cm 2 . The on-board data processor has functions to format telemetry data as well as to control the high voltage of the proportional counters to protect them from the particle irradiation. The paper describes the instruments, on-board data processing, telemetry data formats, and performance specifications expected from the ground calibration tests.

In-Orbit Performance of MAXI Gas Slit Camera (GSC) on ISS

Abstract: We report the in-orbit performance of the Gas Slit Camera (GSC) on the MAXI (Monitor of All-sky X-ray Image) mission carried on the International Space Station (ISS). Its commissioning operation started on August 8, 2009, confirmed the basic performances of the effective area in the energy band of 2–30 keV, the spatial resolution of the slit-and-slat collimator and detector with 1.5 FWHM, the source visibility of 40-150 seconds for each scan cycle, and the sky coverage of 85% per 92-minute orbital period and 95% per day. The gas gains and read-out amplifier gains have been stable within 1%. The background rate is consistent with the past X-ray experiments operated at the similar low-earth orbit if its relation with the geomagnetic cutoff rigidity is extrapolated to the high latitude. We also present the status of the in-orbit operation and the calibration of the effective area and the energy response matrix using Crab-nebula data.

Multi-messenger observations of a binary neutron star merger

Abstract: On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $\sim 1.7\,{\rm{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $\,{M}_{\odot }$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $\sim 40\,{\rm{Mpc}}$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient's position $\sim 9$ and $\sim 16$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.

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.

The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe

Abstract: We summarize what large surveys of the contemporary Universe have taught us about the physics and phenomenology of the processes that link the formation and evolution of galaxies with their central supermassive black holes. We present a picture in which the population of active galactic nuclei (AGNs) can be divided into two distinct populations. The radiative-mode AGNs are associated with black holes (BHs) that produce radiant energy powered by accretion at rates in excess of ∼1% of the Eddington limit. They are primarily associated with less massive BHs growing in high-density pseudobulges at a rate sufficient to produce the total mass budget in these BHs in ∼10 Gyr. The circumnuclear environment contains high-density cold gas and associated star formation. Major mergers are not the primary mechanism for transporting this gas inward; secular processes appear dominant. Stellar feedback is generic in these objects, and strong AGN feedback is seen only in the most powerful AGNs. In jet-mode AGNs the bulk of...

Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A

Abstract: INTRODUCTION Neutrinos are tracers of cosmic-ray acceleration: electrically neutral and traveling at nearly the speed of light, they can escape the densest environments and may be traced back to their source of origin. High-energy neutrinos are expected to be produced in blazars: intense extragalactic radio, optical, x-ray, and, in some cases, γ-ray sources characterized by relativistic jets of plasma pointing close to our line of sight. Blazars are among the most powerful objects in the Universe and are widely speculated to be sources of high-energy cosmic rays. These cosmic rays generate high-energy neutrinos and γ-rays, which are produced when the cosmic rays accelerated in the jet interact with nearby gas or photons. On 22 September 2017, the cubic-kilometer IceCube Neutrino Observatory detected a ~290-TeV neutrino from a direction consistent with the flaring γ-ray blazar TXS 0506+056. We report the details of this observation and the results of a multiwavelength follow-up campaign. RATIONALE Multimessenger astronomy aims for globally coordinated observations of cosmic rays, neutrinos, gravitational waves, and electromagnetic radiation across a broad range of wavelengths. The combination is expected to yield crucial information on the mechanisms energizing the most powerful astrophysical sources. That the production of neutrinos is accompanied by electromagnetic radiation from the source favors the chances of a multiwavelength identification. In particular, a measured association of high-energy neutrinos with a flaring source of γ-rays would elucidate the mechanisms and conditions for acceleration of the highest-energy cosmic rays. The discovery of an extraterrestrial diffuse flux of high-energy neutrinos, announced by IceCube in 2013, has characteristic properties that hint at contributions from extragalactic sources, although the individual sources remain as yet unidentified. Continuously monitoring the entire sky for astrophysical neutrinos, IceCube provides real-time triggers for observatories around the world measuring γ-rays, x-rays, optical, radio, and gravitational waves, allowing for the potential identification of even rapidly fading sources. RESULTS A high-energy neutrino-induced muon track was detected on 22 September 2017, automatically generating an alert that was distributed worldwide within 1 min of detection and prompted follow-up searches by telescopes over a broad range of wavelengths. On 28 September 2017, the Fermi Large Area Telescope Collaboration reported that the direction of the neutrino was coincident with a cataloged γ-ray source, 0.1° from the neutrino direction. The source, a blazar known as TXS 0506+056 at a measured redshift of 0.34, was in a flaring state at the time with enhanced γ-ray activity in the GeV range. Follow-up observations by imaging atmospheric Cherenkov telescopes, notably the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes, revealed periods where the detected γ-ray flux from the blazar reached energies up to 400 GeV. Measurements of the source have also been completed at x-ray, optical, and radio wavelengths. We have investigated models associating neutrino and γ-ray production and find that correlation of the neutrino with the flare of TXS 0506+056 is statistically significant at the level of 3 standard deviations (sigma). On the basis of the redshift of TXS 0506+056, we derive constraints for the muon-neutrino luminosity for this source and find them to be similar to the luminosity observed in γ-rays. CONCLUSION The energies of the γ-rays and the neutrino indicate that blazar jets may accelerate cosmic rays to at least several PeV. The observed association of a high-energy neutrino with a blazar during a period of enhanced γ-ray emission suggests that blazars may indeed be one of the long-sought sources of very-high-energy cosmic rays, and hence responsible for a sizable fraction of the cosmic neutrino flux observed by IceCube.