論文 - 廣島　渚

件数 20 件

First Operation of a Liquid Argon Time Projection Chamber (LArTPC) in the Stratosphere as an Engineering Gamma-Ray and AntiMatter Survey (GRAMS) Balloon Flight (eGRAMS)

Nakajima, R; Arai, S; Aoyama, K; Utsumi, Y; Tamba, T; Odaka, H; Tanaka, M; Yorita, K; Arai, S; Aram … 全著者表示

PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS   2024 ( 12 )   2024年12月  [査読有り]

DOI Web of Science

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   共著  

Dark matter line searches with the Cherenkov Telescope Array

S. Abe, J. Abhir, A. Abhishek, F. Acero,A. Acharyya, R. Adam,A. Aguasca-Cabot, I. Agudo, A. Aguirre … 全著者表示

Journal of Cosmology and Astroparticle Physics   2024   2024年7月

DOI

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   単著  

Search for heavy dark matter from dwarf spheroidal galaxies: leveraging cascades and subhalo models

Deheng Song, Nagisa Hiroshima and Kohta Murase

Journal of Cosmology and Astroparticle Physics   2024 ( 5 )   2024年5月  [査読有り]

DOI Web of Science

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   単著  

Potential of the Cherenkov Telescope Array for studying the young nearby supernova remnants

Dmitry A Prokhorov,Shiu-Hang Lee,Shigehiro Nagataki,Jacco Vink,Donald Ellison,Gilles Ferrand,Daniel … 全著者表示

Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)   2023年8月

DOI

　詳細を見る

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Sissa Medialab   共著  

Sensitivity of the Cherenkov Telescope Array to TeV photon emission from the Large Magellanic Cloud

Acharyya , A.,Adam , R.,Aguasca-Cabot , A.,Agudo , I.,Aguirre-Santaella , A.,Alfaro , J.,Aloisio , … 全著者表示

Monthly Notices of the Royal Astronomical Society   523 ( 4 )   5353 - 5387   2023年5月  [査読有り]

DOI

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Oxford University Press (OUP)   共著  

A deep survey of the Large Magellanic Cloud at ~0.1-100 TeV photon energies with the Cherenkov Telescope Array is planned. We assess the detection prospects based on a model for the emission of the galaxy, comprising the four known TeV emitters, mock populations of sources, and interstellar emission on galactic scales. We also assess the detectability of 30 Doradus and SN 1987A, and the constraints that can be derived on the nature of dark matter. The survey will allow for fine spectral studies of N 157B, N 132D, LMC P3, and 30 Doradus C, and half a dozen other sources should be revealed, mainly pulsar-powered objects. The remnant from SN 1987A could be detected if it produces cosmic-ray nuclei with a flat power-law spectrum at high energies, or with a steeper index 2.3-2.4 pending a flux increase by a factor >3-4 over ~2015-2035. Large-scale interstellar emission remains mostly out of reach of the survey if its >10 GeV spectrum has a soft photon index ~2.7, but degree-scale 0.1-10 TeV pion-decay emission could be detected if the cosmic-ray spectrum hardens above >100 GeV. The 30 Doradus star-forming region is detectable if acceleration efficiency is on the order of 1 - 10 per cent of the mechanical luminosity and diffusion is suppressed by two orders of magnitude within <100 pc. Finally, the survey could probe the canonical velocity-averaged cross section for self-annihilation of weakly interacting massive particles for cuspy Navarro-Frenk-White profiles....

その他リンク： https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stad1576/50461207/stad1576.pdf

Search for Gamma-Ray Spectral Lines from Dark Matter Annihilation up to 100 TeV toward the Galactic Center with MAGIC

H. Abe,S. Abe,V.A. Acciari,T. Aniello,S. Ansoldi,L.A. Antonelli,A. Arbet Engels,C. Arcaro,M. Artero … 全著者表示

Physical Review Letters   130 ( 6 )   2023年2月

DOI

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Physical Society (APS)   共著  

その他リンク： https://link.aps.org/article/10.1103/PhysRevLett.130.061002

Constraining the primordial curvature perturbation using dark matter substructure

Shin’ichiro Ando,Nagisa Hiroshima,Koji Ishiwata

Physical Review D   106 ( 10 )   2022年11月  [査読有り]

DOI

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Physical Society (APS)   共著  

その他リンク： https://link.aps.org/article/10.1103/PhysRevD.106.103014

Semi-analytical frameworks for subhaloes from the smallest to the largest scale

Nagisa Hiroshima,Shin’ichiro Ando,Tomoaki Ishiyama

Monthly Notices of the Royal Astronomical Society   517 ( 2 )   2728 - 2737   2022年10月  [査読有り]

DOI

　詳細を見る

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Oxford University Press (OUP)   共著  

ABSTRACT
Substructures of dark matter halo, called subhaloes, provide important clues to understand the nature of dark matter. We construct a useful model to describe the properties of subhalo mass functions based on the well-known analytical prescriptions, the extended Press–Schechter theory. The unevolved subhalo mass functions at arbitrary mass scales become describable without introducing free parameters. The different host halo evolution histories are directly recast to their subhalo mass functions. As applications, we quantify the effects from (i) the Poisson fluctuation, (ii) the host-mass scatter, and the (iii) different tidal evolution models on observables in the current Universe with this scheme. The Poisson fluctuation dominates in the number count of the mass ratio to the host of $ sim { cal O}(10^{-2})$, where the intrinsic scatter is smaller by a factor of a few. The host-mass scatter around its mean does not affect the subhalo mass function. Different models of the tidal evolution predict a factor of ∼2 difference in numbers of subhaloes with lesssim { cal O}(10^{-5}), while the dependence of the Poisson fluctuation on the tidal evolution models is subtle. The scheme provides a new tool for investigating the smallest scale structures of our Universe which are to be observed in near future experiments.

その他リンク： https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stac2857/46385435/stac2857.pdf

Impacts of new small-scale N-body simulations on dark matter annihilations constrained from cosmological 21-cm line observations

Nagisa Hiroshima,Kazunori Kohri,Toyokazu Sekiguchi,Ryuichi Takahashi

Physical Review D   104 ( 8 )   2021年10月  [査読有り]

DOI

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Physical Society (APS)   共著  

その他リンク： https://link.aps.org/article/10.1103/PhysRevD.104.083547

MeV-scale reheating temperature and cosmological production of light sterile neutrinos

Takuya Hasegawa,Nagisa Hiroshima,Kazunori Kohri,Rasmus S. L. Hansen,Thomas Tram,Steen Hannestad

Journal of Cosmology and Astroparticle Physics   2020 ( 8 )   15   2020年3月  [査読有り]

DOI arXiv

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   共著  

We investigate how sterile neutrinos with a range of masses influence
cosmology in MeV-scale reheating temperature scenarios. By computing the
production of sterile neutrinos through the combination of mixing and
scattering in the early Universe, we find that light sterile neutrinos, with
masses and mixings as inferred from short-baseline neutrino oscillation
experiments, are consistent with big-bang nucleosynthesis (BBN) and cosmic
microwave background (CMB) radiation for the reheating temperature of ${ cal
O}(1)$ MeV if the parent particle responsible for reheating decays into
electromagnetic components (radiative decay). In contrast, if the parent
particle mainly decays into hadrons (hadronic decay), the bound from BBN
becomes more stringent. In this case, the existence of the light sterile
neutrinos can be cosmologically excluded, depending on the mass and the
hadronic branching ratio of the parent particle.

その他リンク： http://arxiv.org/abs/2003.13302v2

Structure Formation Models Weaken Limits on WIMP Dark Matter from Dwarf Spheroidal Galaxies

Shin'ichiro Ando,Alex Geringer-Sameth,Nagisa Hiroshima,Sebastian Hoof,Roberto Trotta,Matthew G. Wal … 全著者表示

Physical Review D   102 ( 61302 )   2020年2月  [査読有り]

DOI arXiv

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   共著  

Dwarf spheroidal galaxies that form in halo substructures provide stringent
constraints on dark matter annihilation. Many ultrafaint dwarfs discovered with
modern surveys contribute significantly to these constraints. At present,
because of the lack of abundant stellar kinematic data for the ultrafaints,
non-informative prior assumptions are usually made for the parameters of the
density profiles. Based on semi-analytic models of dark matter subhalos and
their connection to satellite galaxies, we present more informative and
realistic satellite priors. We show that our satellite priors lead to
constraints on the annihilation rate that are between a factor of 2 and a
factor of 7 weaker than under non-informative priors. As a result, the thermal
relic cross section can at best only be excluded (with 95% probability) for
dark matter masses of $ lesssim 40$ GeV from dwarf spheroidal data, assuming
annihilation into $b bar{b}$.

その他リンク： http://arxiv.org/abs/2002.11956v2

MeV-scale reheating temperature and thermalization of oscillating neutrinos by radiative and hadronic decays of massive particles

Takuya Hasegawa,Nagisa Hiroshima,Kazunori Kohri,Rasmus S. L. Hansen,Thomas Tram,Steen Hannestad

Journal of Cosmology and Astroparticle Physics,   2019 ( 12 )   12   2019年12月  [査読有り]

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   共著  

Halo Substructure Boosts to the Signatures of Dark Matter Annihilation

Shin'ichiro Ando,Tomoaki Ishiyama,Nagisa Hiroshima

Galaxies   7   68   2019年7月  [査読有り]  [招待有り]

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   共著  

Dependence of accessible dark matter annihilation cross-sections on the density profiles of dwarf spheroidal galaxies with the Cherenkov Telescope Array

Nagisa Hiroshima,Masaaki Hayashida,Kazunori Kohri

Physical Review D   99 ( 12 )   123017   2019年5月  [査読有り]

DOI arXiv

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   共著  

Dwarf spheroidal galaxies are excellent targets in gamma-ray searches for
dark matter. We consider dark matter searches in dwarf spheroidal galaxies
(dSphs) with the Cherenkov Telescope Array (CTA). The aim of this work is to
reveal a quantitative and precise dependence of the accessible dark matter
annihilation cross-sections on the dark matter density profiles of dSphs and on
the distance to them. In most data analyses, researchers have assumed
point-like signals from dSphs because it is difficult to resolve the expected
emission profiles with current gamma-ray observatories. In future however, CTA
will be able to resolve the peak emission profiles in dSphs. We take several
variations of the dark matter density profile of Draco dSph as examples and
analyze the simulated observations of with CTA. We derive the accessible region
of the dark matter annihilation cross-section with each dark matter density
profile. The accessible region of the annihilation cross-section can differ by
a factor of 10 among plausible profiles. We also examine the dependence on the
distance to the target dSphs by assuming the same profiles of dSphs at
different distances. Closer targets are better due to the higher J-factor,
while their spatial extension significantly degrades our reach to the
annihilation cross-section compared to the value expected from a simple
distance-scaling of the J-factor. Spatial extension of the source affects the
probable parameter region in energy-dependent ways. In some gamma-ray energy
ranges, this behaviour becomes moderately dependent on the properties of the
observation facility.

その他リンク： http://arxiv.org/abs/1905.12940v1

高エネルギーガンマ線による暗黒物質探査

廣島 渚

東京大学理学系研究科   2019年3月  [査読有り]

　詳細を見る

記述言語：英語   掲載種別：研究論文（大学，研究機関紀要）   単著  

Modeling evolution of dark matter substructure and annihilation boost

Nagisa Hiroshima,Shin'ichiro Ando,Tomoaki Ishiyama

Physical Review D   97 ( 12 )   123002   2018年6月  [査読有り]

DOI arXiv

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   共著  

We study evolution of dark matter substructures, especially how they lose the
mass and change density profile after they fall in gravitational potential of
larger host halos. We develop an analytical prescription that models the
subhalo mass evolution and calibrate it to results of N-body numerical
simulations of various scales from very small (Earth size) to large (galaxies
to clusters) halos. We then combine the results with halo accretion histories,
and calculate the subhalo mass function that is physically motivated down to
Earth-mass scales. Our results --- valid for arbitrary host masses and
redshifts --- show reasonable agreement with those of numerical simulations at
resolved scales. Our analytical model also enables self-consistent calculations
of the boost factor of dark matter annhilation, which we find to increase from
tens of percent at the smallest (Earth) and intermediate (dwarfs) masses to a
factor of several at galaxy size, and to become as large as a factor of
$ sim$10 for the largest halos (clusters) at small redshifts. Our analytical
approach can accommodate substructures in the subhalos (sub-subhalos) in a
consistent framework, which we find to give up to a factor of a few enhancement
to the annihilation boost. Presence of the subhalos enhances the intensity of
the isotropic gamma-ray background by a factor of a few, and as the result, the
measurement by Fermi Large Area Telescope excludes the annihilation cross
section greater than $ sim$$4 times 10^{-26}$ cm$^3$ s$^{-1}$ for dark matter
masses up to $ sim$200 GeV.

その他リンク： http://arxiv.org/abs/1803.07691v2

Constraints on small-scale primordial power by annihilation signals from extragalactic dark matter minihalos

Tomohiro Nakama,Teruaki Suyamama,Kazunori Kohri,Nagisa Hiroshima

Physical Review D   97 ( 2 )   23539   2018年1月  [査読有り]

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   共著  

High-energy neutrinos from multibody decaying dark matter

Nagisa Hiroshima,Ryuichiro Kitano,Kazunori Kohri,Kohta Murase

Physical Review D   97 ( 2 )   23006   2018年1月  [査読有り]

DOI Scopus arXiv

　詳細を見る

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Physical Society   共著  

Since the report of the PeV-TeV neutrinos by the IceCube Collaboration,
various particle physics models have been proposed to explain the neutrino
spectrum by dark matter particles decaying into neutrinos and other Standard
Model particles.In such scenarios, simultaneous $ gamma$-ray emission is
commonly expected. Therefore, multi-messenger connections are generally
important for the indirect searches of dark matters. The recent development of
$ gamma$-ray astronomy puts stringent constraints on the properties of dark
matter, especially by observations with the Fermi $ gamma$-ray satellite in the
last several years. Motivated by the lack of $ gamma$-ray as well as the shape
of the neutrino spectrum observed by IceCube, we discuss a scenario in which
the DM is a PeV scale particle which couples strongly to other invisible
particles and its decay products do not contain a charged particle. As an
example to realize such possibilities, we consider a model of fermionic dark
matter that decays into a neutrino and many invisible fermions. The dark matter
decay is secluded in the sense that the emitted products are mostly neutrinos
and dark fermions. One remarkable feature of this model is the resulting
broadband neutrino spectra around the energy scale of the dark matter. We apply
this model to multi-PeV dark matter, and discuss possible observable
consequences in light of the IceCube data. In particular, this model could
account for the large flux at medium energies of $ sim10-100$ TeV, possibly as
well as the second peak at PeV, without violating the stringent $ gamma$-ray
constraints from Fermi and air-shower experiments such as CASA-MIA.

その他リンク： http://arxiv.org/abs/1705.04419v2

CTA報告147：全体報告

窪 秀利,井上 剛志,深沢 泰司,深見 哲志,福井 康雄,藤田 裕,藤原 千賀己,古田 智也,He Haoning,Majumdar Pratik,Mazin Daniel,増田 周,井上 芳幸,松 … 全著者表示

日本物理学会講演概要集   74   556 - 556   1905年7月

DOI

　詳細を見る

記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）   出版者・発行元：一般社団法人 日本物理学会   共著  

CTA報告139：全体報告

窪 秀利,井上 剛志,深見 哲志,福井 康雄,藤田 裕,藤原 千賀己,He Haoning,Majumdar Pratik,Mazin Daniel,増田 周,松本 浩典,三浦 智佳,井上 芳幸,水 … 全著者表示

日本物理学会講演概要集   73 ( 0 )   188 - 188   1905年7月

DOI

　詳細を見る

記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）   出版者・発行元：一般社団法人 日本物理学会   共著  

その他リンク： https://ci.nii.ac.jp/naid/130007735527