Susumu Inoue
A5089094131- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Neutrino Physics Research
- Astrophysical Phenomena and Observations
- Particle Detector Development and Performance
- Pulsars and Gravitational Waves Research
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Particle physics theoretical and experimental studies
- Astro and Planetary Science
- Particle Accelerators and Free-Electron Lasers
- Solar and Space Plasma Dynamics
- Stellar, planetary, and galactic studies
- Radiation Detection and Scintillator Technologies
- Cosmology and Gravitation Theories
- Astrophysics and Star Formation Studies
- Advanced X-ray and CT Imaging
- Nuclear Physics and Applications
- Planetary Science and Exploration
- Ionosphere and magnetosphere dynamics
- History and Developments in Astronomy
- Atmospheric Ozone and Climate
- Medical Imaging Techniques and Applications
The University of Tokyo
2013-2025
Chiba University
2024-2025
Tokyo Metropolitan University
1997-2024
Nitto RIKEN (Japan)
2016-2024
University of Groningen
2023
Istituto Nazionale di Fisica Nucleare, Sezione di Torino
2019-2023
RIKEN
2015-2023
Nippon Soken (Japan)
2018-2023
Centre National de la Recherche Scientifique
2016-2023
Taras Shevchenko National University of Kyiv
2021-2023
Current Cherenkov telescopes have identified a population of ultra-high-frequency peaked BL Lac objects (UHBLs), also known as extreme blazars, that exhibit exceptionally hard TeV spectra, including 1ES 0229+200, 0347-121, RGB J0710+591, 1101-232, and 1218+304. Although one-zone synchrotron-self-Compton (SSC) models been generally successful in interpreting the high-energy emission observed other objects, they are problematic for UHBLs, necessitating very large Doppler factors and/or...
Abstract A neutrino with energy ∼290 TeV, IceCube-170922A, was detected in coincidence the BL Lac object TXS 0506+056 during enhanced gamma-ray activity, chance being rejected at ∼3 σ level. We monitored very-high-energy (VHE) band Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes for ∼41 hr from 1.3 to 40.4 days after detection. Day-timescale variability is clearly resolved. interpret quasi-simultaneous and broadband electromagnetic observations a novel one-zone...
view Abstract Citations (222) References (52) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Electron Acceleration and Gamma-Ray Emission from Blazars Inoue, Susumu ; Takahara, Fumio The high-energy gamma rays blazars detected by EGRET/CGRO are interpreted as photons that inverse-Compton scattered shock- accelerated electrons in jets. Within a simplified one-zone model framework, we calculate broadband blazar spectra utilizing electron distributions...
We discuss the effect of dispersion delay due to intervening ionized media in radio emission gamma-ray bursts (GRBs). For high redshift GRBs ($z \ga 3$), intergalactic medium (IGM) should be dominant source without substantial local or foreground contamination, offering a unique probe cosmic reionization epoch through measures free electron column density out different redshifts. The times from $z \sim 10$ can $\sim$ 1 hour at 100 MHz and 10 hours 30 MHz. On other hand, by material may...
While active galactic nuclei with relativistic jets have long been prime candidates for the origin of extragalactic cosmic rays and neutrinos, BL Lac object TXS 0506+056 is first astrophysical source observed to be associated some confidence ($\sim 3\sigma$) a high-energy neutrino, IceCube-170922A, detected by IceCube Observatory. The was found in gamma-rays Fermi-LAT very-high-energy MAGIC telescopes. To consistently explain neutrino multi-wavelength electromagnetic emission 0506+056, we...
We present a new model of the extragalactic background light (EBL) and corresponding γγ opacity for intergalactic gamma-ray absorption from z = 0 up to 10, based on semi-analytical hierarchical galaxy formation that reproduces key observed properties galaxies at various redshifts. Including potential contribution Population III stars following cosmic reionization history in simplified way, is also broadly consistent with available data concerning reionization, particularly Thomson scattering...
Concerted effort is currently ongoing to open up the Epoch of Reionization (z ∼15-6) for studies with IR and radio telescopes.Whereas detections have been made sources (Lyman-α emitters, quasars drop-outs) in this redshift regime relatively small fields view, no direct detection neutral hydrogen, via redshifted 21-cm line, has yet established.Such a expected coming years, surveys, could entire universe from z ∼6-200 astrophysical cosmological studies, opening not only Reionization, but also...
We present a measurement of the extragalactic background light (EBL) based on joint likelihood analysis 32 gamma-ray spectra for 12 blazars in redshift range z = 0.03 to 0.944, obtained by MAGIC telescopes and Fermi-LAT. The EBL is part diffuse radiation spanning ultraviolet, visible infrared bands. Major contributors are emitted stars through history universe, fraction it which was absorbed dust galaxies re-emitted at longer wavelengths. can be studied indirectly its effect very-high energy...
On January 14, 2019, the Major Atmospheric Gamma Imaging Cherenkov telescopes detected GRB 190114C above 0.2 TeV, recording most energetic photons ever observed from a gamma-ray burst. We use this unique observation to probe an energy dependence of speed light in vacuo for as predicted by several quantum gravity models. Based on set assumptions possible intrinsic spectral and temporal evolution, we obtain competitive lower limits quadratic leading order modification.
We present the results of a multiwavelength campaign for Mrk 501 performed in 1996 March with ASCA, EGRET, Whipple, and optical telescopes. The X-ray flux observed ASCA was 5 times higher than quiescent level gradually decreased by factor 2 during observation March. In band, spectral break around keV. report here first time detection high-energy γ-ray from EGRET 3.5 σ significance (E>100 MeV). Higher also April-May, 4.0 E>100 MeV 5.2 E>500 MeV. spectrum measured to be flatter most blazars....
Accretion and merger shocks in clusters of galaxies are potential accelerators high-energy protons, which can give rise to neutrinos through pp interactions with the intracluster gas. We discuss possibility that protons from cluster make a significant contribution observed cosmic rays energy range between second knee around 10^17.5 eV ankle 10^18.5 eV. The accompanying cumulative neutrino background above PeV may be detectable by upcoming telescopes such as IceCube or KM3NeT, providing test...
We argue that the excess of sub-PeV/PeV neutrinos recently reported by IceCube could plausibly originate through pion-production processes in same sources responsible for cosmic rays (CRs) with energy above second knee around $10^{18}\,$eV. The pion production efficiency escaping CRs produce PeV is required to be $\gtrsim 0.1$ such sources. On basis current data, we identify semi-relativistic hypernova remants as possible satisfy requirements. By virtue their fast ejecta, objects can...
Abstract Recent observations with ALMA have revealed evidence for nonthermal synchrotron emission from the core regions of two nearby Seyfert galaxies. This suggests that coronae accretion disks in active galactic nuclei (AGNs) can be conducive to acceleration electrons, addition hot, thermal electrons responsible their X-ray through Comptonization. Here, we investigate mechanism such particle acceleration, based on observationally inferred parameters AGN disk coronae. One possibility...
The coincident detection of GW170817 in gravitational waves and electromagnetic radiation spanning the radio to MeV gamma-ray bands provided first direct evidence that short bursts (GRBs) can originate from binary neutron star (BNS) mergers. On other hand, properties GRBs high-energy gamma rays are still poorly constrained, with only $\sim$20 events detected GeV band, none TeV band. GRB~160821B is one nearest known at $z=0.162$. Recent analyses multiwavelength observational data its...
Abstract We have found a class of circular radio objects in the Evolutionary Map Universe Pilot Survey, using Australian Square Kilometre Array Pathfinder telescope. The appear images as edge-brightened discs, about one arcmin diameter, that are unlike other previously reported literature. explore several possible mechanisms might cause these objects, but none seems to be compelling explanation.
We present data for 18 blazars observed with the X-ray satellite ASCA, half of which were also contemporaneously EGRET instrument onboard Compton Gamma Ray Observatory as parts multiwavelength campaigns. The observations show a clear difference in spectra between three subclasses blazars, namely, high-energy peaked BL Lacertae objects (HBLs), low-energy Lac (LBLs), and quasar-hosted (QHBs). ASCA HBLs are softest, power-law energy index α ~ 1-2, they form highest observable tail (LE,...
We have studied the rapid X-ray variability of three extragalactic TeV gamma-ray sources; Mrk 421, 501 and PKS 2155-304. Analyzing light curves obtained from ASCA and/or RXTE observations between 1993 1998, we investigated in time domain 10^3 to 10^8 sec. For all sources, both power spectrum density (PSD) structure function (SF) show a roll-over with time-scale order 1 day or longer, which may be interpreted as typical successive flare events. Although exact shape turn-over is not well...
The prompt emission of gamma-ray bursts (GRBs) is widely thought to be radiation from accelerated electrons, but an appreciably larger amount energy could carried by protons, particularly if GRBs are the sources ultra-high-energy cosmic rays (UHECRs). We model expected photon spectra for such "proton-dominated" in internal shock scenario through Monte Carlo simulations, accounting various processes related high-energy electrons and protons. Besides proton muon synchrotron components,...
More than a dozen blazars are known to be emitters of multi-TeV gamma rays, often with strong and rapid flaring activity. By interacting photons the cosmic microwave infrared backgrounds, these rays inevitably produce electron-positron pairs, which in turn radiate secondary inverse Compton GeV-TeV range characteristic time delay that depends on properties intergalactic magnetic field (IGMF). For sufficiently weak IGMF, such "pair echo" emission may detectable by Gamma-ray Large Area Space...