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due to unusually quiet solar activity conditions during the previous 2009 and 2020 solar minima, record high levels of galactic cosmic rays (gcrs) were reported. however, anomalous cosmic ray (acr) intensities did not show such extremely high levels. this discrepancy between gcr and acr intensities remains unresolved. ... | simulating gcr and acr oxygen intensities during very quiet solar minimum conditions |
the large area telescope (lat), on-board the fermi satellite, proved to be, after 8 years of data taking, an excellent instrument to detect and observe supernova remnants (snrs) in a range of energies running from few hundred mev up to few hundred gev. it provides essential information on physical processes that occur ... | supernova remnants with fermi large area telescope |
in the extreme environment of the galactic center, the magnetic fieldmay play a key role in regulating the ism. we propose a deep xmm-newtonobservation of g0.17-0.41 -- a distinct 2.6'-long x-ray thread embeddedwell within a locally broadened nonthermal radio filament. thisx-ray/radio association provides probably the ... | exploring the nature of the x-ray thread g0.17-0.41 in the galactic center |
accretion of gas onto already virialized structures like galaxy clusters should give rise to accretion shocks which can potentially accelerate cosmic rays. here, we use the radio emission detected from coma cluster and models of evolution of cosmic accretion shocks, to constrain the possible contribution of unresolved ... | constraining the collective radio emission of large scale accretion shocks |
massive stars have a profound astrophysical influence throughout their tumultuous lives and deaths. stellar feedback - the injection of energy and momentum by stars to the interstellar medium (ism) - occurs through a variety of mechanisms: radiation, photoionization heating, winds, jets/outflows, supernovae, and cosmic... | the tumultuous lives and deaths of stars |
the global records of infectious diseases, including western and eastern documents from 1825 to 2020, during which sunspot observations are considered reliable, show that 27 of the 34 pandemic outbreaks were coincident with sunspot number maxima or minima. there is evidence that the intensity of galactic cosmic rays is... | relation of pandemics with solar cycles through ozone, cloud seeds, and vitamin d |
under nonuniform convection, the distribution of diffusive particles can exhibit dipole and quadrupole anisotropy induced by the fluid inertial and shear force, respectively. these convection-related anisotropies, unlike the compton-getting effect, typically increase with the cosmic-ray (cr) energy, and are thus candid... | cosmic-ray convection-diffusion anisotropy |
the boltzmann-gibbs thermodynamic equilibrium state of charged particles pitch-angle scattered by weak plasma waves is discussed. degrees of freedom of these waves play a fundamental role in constructing the grand canonical ensemble. via the gyro-resonance condition, fast particles have an inverse break power-law spect... | power-law spectrum of energetic particles in classical thermal equilibrium by pitch-angle scattering process |
the mechanism accelerating cosmic rays in the milky way galaxy and galaxy clusters is identified and described. the acceleration of cosmic rays is a purely electrostatic process which operates up to the maximum energies of $10^{23}$ ev in galaxy clusters. galactic cosmic rays are accelerated in a pervasive electrostati... | the ubiquitous mechanism accelerating cosmic rays at all the energies |
the supertiger (trans-iron galactic element recorder) experiment was launched on a long-duration balloon flight from williams field, antarctica, on december 8, 2012. supertiger flew for a total of 55 days at a mean atmospheric depth of 4.4 g/cm2. the instrument measured the abundances of galactic cosmic rays in the cha... | ultra-heavy galactic cosmic ray abundances from the supertiger instrument |
cosmic rays (crs) are highly energetic nuclei (plus a small fraction of electrons) which fill the galaxy and carry on average as much energy per unit volume as the energy density of starlight, the interstellar magnetic fields, or the kinetic energy density of interstellar gas. the cr spectrum extends as a featureless p... | gamma rays and the origin of galactic cosmic rays |
magnetic fields are important ingredients in the interstellar medium of galaxies. they accelerate cosmic rays, affect star formation, and regulate the redistribution of matter and energy. despite their ubiquitous presence, the growth and coevolution of magnetic fields with galactic processes are not well understood. we... | magnetic fields in ngc 6946 using wide-band radio polarimetry |
cosmological constraints from x-ray and microwave observations of galaxy clusters are subjected to systematic uncertainties. non-thermal pressure support due to internal gas motions in galaxy clusters is one of the major sources of astrophysical uncertainties, which result in large bias and scatter in the hydrostatic m... | effects of mergers and dynamical state on galaxy clusters in cosmological simulations |
owing to their utility for measurements of cosmic acceleration, type ia supernovae (sne ia) are perhaps the best-studied class of sne, yet the progenitor systems of these explosions largely remain a mystery. a rare subclass of sne ia shows evidence of strong interaction with their circumstellar medium (csm), and in par... | type ia supernovae strongly interacting with their circumstellar medium |
it will be presents an original etching-based technique of search for and analysis of tracks of heavy cosmic ray nuclei (z > 26) in olivine crystals from meteorites, developed by the authors team. this enabled detecting and identifying 21,743 galactic cosmic ray tracks of nuclei heavier than iron in the olivine crys... | investigations of the tracks of galactic cosmic ray nuclei in olivines from meteorites |
it is currently accepted that supernova remnants are the main sites where galactic cosmic rays undergo acceleration. though this picture is energetically sustentable, the models predict spectra that do not match observations. on the other hand, the contribution of other kind of sources to the galactic cosmic-ray popula... | microcuásares como fuentes de rayos cósmicos |
recently, a diffuse γ-rays emission in the energy range 1-100 gev has been detected around m31, that extends up to 120-200 kpc from its center. such extended emission is difficult to be explained in the typical scenario of cosmic rays produced in the galactic disk or in the galactic center (gc) and diffusing in the gal... | giant cosmic ray halos around m31 and the milky way |
outflows are ubiquitous phenomena in the universe. they have been widely observed in both galactic and extragalactic objects. in this thesis, we analyze three individual sources. firstly, we re-analyze the high energy gamma-ray data of fermi-lat on the giant lobes of centaurus a. we utilize for the first time the planc... | nonthermal processes of fast outflows from astrophysical objects |
passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. while space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen conten... | measuring space radiation shielding effectiveness |
while from the energetic point of view snrs are viable sources of galactic crs, the issue of whether they can accelerate protons up to pev remains unsolved. here we discuss particle acceleration at the forward shock of sn and discuss the possibility that the escaping particle current may excite a non-resonant instabili... | on the cosmic ray spectrum from type ii supernovae expanding in their red giant presupernova wind |
we present new karl g. jansky very large array (jvla) observations of the merging galaxy cluster zwcl2341.1+0000 located at z=0.27. this cluster is known to contain two diffuse radio sources, the largest being about 1 mpc in size, located on opposite sides of the cluster center. the sources are separated by about 2 mpc... | jvla observations of cosmic rays in the galaxy cluster zwcl2341.1+0000 |
there are only a few pevatron candidates known in our galaxy which might contribute particles up to the knee of the cosmic-ray spectrum. hess j1641.0-4619, a gamma-ray source located in the galactic plane and detected by h.e.s.s. above 4 tev, is one of them. characterized as a point source with a hard spectral index, h... | efficient particle acceleration from hess j1640.6-4633 and the pevatron candidate hess j1641.0-4619 |
supertiger (super trans-iron galactic element recorder) is a large-area instrument designed to make precision measurements of the elemental composition of ultra-heavy galactic cosmic rays (uhgcr) with atomic number z $\ge$ 30. the abundance measurements provide sensitive tests and clarification of the ob-association mo... | overview and preliminary results of the supertiger-2 flight |
the high energy charged particle environment (i.e. >30 mev protons and ~2 mev electrons) in mars orbit is of interest both in terms of the science of the heliosphere and of the space radiation hazard to key orbital assets and astronaut health. these particles have two primary sources: a) galactic cosmic rays which f... | understanding high-energy particle radiation in mars orbit: combining data sets from mars global surveyor and mars express |
there are gaps in our current understanding of how massive galaxies undergo the transformation from actively forming stars to quiescence with negligible ongoing star formation. most massive galaxies in the local universe quenched their star formation billions of years ago, and there is theoretical and observational evi... | compact starburst galaxies with fast outflows: constraints on recent star formation and outflow properties from optical spectroscopy and multi-wavelength photometry |
active galactic nuclei (agn), powered by accretion onto a central supermassive black hole in their host galaxies, are the most luminous persistent sources of electromagnetic radiation in the universe. non-thermal emission from agn jets is observed across the electromagnetic spectrum, up to tens of tev in the gamma-ray ... | high-energy neutrinos as a multi-messenger probe of supermassive black hole environments |
through observations in very-high-energy (vhe) $\gamma$-rays, the high energy stereoscopic system (hess) allowed studying the properties of the vhe $\gamma$-ray emission from the galactic center (gc) between 0.1~tev and 100~tev. hess observed a $\gamma$-ray diffuse emission strongly correlated with the central molecula... | vhe \\gamma-rays from the galactic center generated by cosmic rays |
supernova remnant is an important source of the interstellar medium, and important mediation to understand the mechanisms of supernova explosions, the acceleration of galactic cosmic-rays, and the abundance of chemical elements in the interstellar medium. an accurate measurement of the distance to an snr can better con... | measure distances of supernova remnants using red clump stars |
galaxy cluster mergers generate shocks and turbulence in the intracluster medium. diffuse cluster radio sources are proposed to trace cosmic rays accelerated by these shocks and turbulence. we propose to observe three nearby galaxy clusters that host extended radio emission at 150 mhz which were missed by previous surv... | a first characterization of galaxy clusters hosting diffuse low-frequency radio emission |
magic is a ground-based imaging atmospheric cherenkov telescope (iact) for gamma-ray astrophysics in the very high energy domain, which pioneered high-sensitivity measurements down to a few tens of gev. it includes two 17m diameter telescopes, operating in a coincidence (stereo) mode. the telescopes are located at 2200... | selected studies of cosmic rays and acceleration sites with the magic telescopes |
solar wind turbulence is responsible for many physical phenomena in the heliosphere including energetic cosmic particle transport and acceleration. turbulence is generated in the solar wind by three major sources, these being shocks and stream-stream interactions in the inner heliosphere and by the generation of pick-u... | turbulent properties of the solar wind within corotating interaction regions: superposed epoch analysis of simulations and observations |
the central few hundred parsecs of the galaxy harbors 5-10% of the molecular gas mass of the entire milky way. this central molecular zone exhibits 6.4 kev fe kα line and continuum x-ray emission with time-variability. the time-variable x-ray emission from the gas clouds is best explained by light echoes of past x-ray ... | probing galactic center cosmic-rays in the x-ray regime |
the heliopause (hp) separates the tenuous hot heliosheath plasma from the relatively dense cool magnetized plasma of the local interstellar medium (lism). fluid acceleration in the hp region can therefore drive rayleigh-taylor-like and kelvin-helmholtz- like instabilities. charge exchange coupling of plasma ions and pr... | instability of the heliopause |
most modeling attempts of blazars use a small emission zone located close to the central black hole in order to explain the broad-band spectral energy distribution. here we present a case where additionally to the small region a >kpc-scale jet is required to successfully reproduce the spectrum and especially the tev... | the extended jet in ap librae as the source of the vhe γ-ray emission |
the effect of particle radiation on materials-of-construction used in inflatable habitat, composite habitat, and space suits was investigated. the materials irradiated are lightweight candidates having a variety of applications such as permeation barriers, micrometeoroid and orbital debris (mmod) protective layers, and... | particle radiation effects representing gcr and spe space radiation on spacecraft and spacesuit materials-of-construction |
galactic-scale superbubbles, such as the fermi bubble in the milky way, could be produced either by an agn or starburst. until now, the best studied superbubble in an external galaxy is in ngc3079, which hosts both an agn and nuclear starburst, leading to some uncertainties in explaining the result. we propose chandra ... | non-thermal hard x-ray emission from a superbubble in a non-starburst galaxy |
ic 443 is a middle-aged supernova remnant (snr) in our galaxy. a gamma-ray spectrum of ic 443 shows a pion-decay signature, which means that cosmic-ray protons are accelerated in the snr (ackermann et al. 2013, sci, 339, 807). since pion production requires cosmic-ray protons with > 280 mev, gamma-ray observations c... | discovery of a 6.4 kev emission line in the supernova remnant ic 443: fluorescence induced by low-energy cosmic rays? |
the cosmological concordance model (λcdm) well accounts for a wealth of observations, from the existence of cosmic microwave background (cmb) to the discovery of the accelerated expansion of the universe from type ia supernovae. yet, it assumes a still unknown form of dark energy and matter and some tensions arose rece... | discovery of a 4σ deviation from λcdm using the hubble diagram of quasars |
the powerful winds of highly-evolved wolf-rayet (wr) stars enrich the ism with metal-rich material to be recycled into future generations of stars. their supersonic winds create shocks that are potential sites of galactic cosmic ray acceleration and diffuse x-ray emission. the wr 38 complex harbors a rich collection of... | a panoramic x-ray view of the wr 38 wolf-rayet cluster |
superbubbles are powered by the stellar winds and subsequent supernovae of a massive stellar population and are often argued as strong candidates for galactic cosmic-ray acceleration sites. the recent detection of tev gamma-rays from 30 dor c in the large magellanic cloud by the high energy stereoscopic system (h.e.s.s... | magnetic field estimates from the synchrotron x-ray shell of 30 dor c, the first tev superbubble |
supernova remnants (snrs) are a very well studied class of objects in our galaxy and are closely related to the origin of cosmic rays (crs), being candidates to host the acceleration process of galactic crs. accelerated particles in snrs can produce γ-rays through interactions with gas (nucleon-nucleon interactions or ... | fermi-lat highlights on supernova remnants |
voyager 1 (v1), before it entered the local interstellar medium (lism) in the summer of 2012, observed a series of increases and decreases in the galactic cosmic ray (gcr) nuclei (mainly protons with energies exceeding 70 mev) fluxes. this remarkable feature was accompanied by the corresponding decreases and increases ... | heliopause instability and its relation to variations in the galactic cosmic ray flux at voyager 1 |
supernova remnants (snrs) have long been thought to be the main source of galactic cosmic rays up to pev energies, and many of them have been shown to accelerate particles to very high energies. but which of them do indeed accelerate a significant number of protons and nuclei? and up to which energies can they accelera... | the gamma cygni supernova remnant at the highest energies |
galaxy clusters are predicted to produce gamma-ray emission, through cosmic ray interaction and/or dark matter annihilation, potentially detectable by the fermi large area telescope (fermi-lat). specifically, cosmic ray interactions with the intra-cluster gas results in neutral pion decay, producing gamma-rays. as yet,... | new limits on gamma-ray emission from galaxy clusters |
voyager 1 continues to observe time-varying enhancements and reductions in galactic cosmic-ray protons related to solar-induced transient events in the very local interstellar medium. the intensity reductions are characterized by a depletion of particles with pitch angles near 90-deg, while other directions remain gene... | voyager 1 galactic cosmic-ray anisotropies: electron observations in the very local interstellar medium |
in about eight years of data taking, the large area telescope (lat) onboard the fermi satellite proved to be an excellent instrument to detect and observe supernova remnants (snrs) in the γ-ray energy band, from less than one hundred mev to a few hundred gev. this energy range is crucial to provide information on the p... | fermi-lat observations of supernova remnants |
this lecture reviews recent investigations of the dynamical effects of cosmic rays (crs) in the interstellar medium of disk galaxies. we focus on the role of crs for generation of galactic magnetic fields as well as galactic winds. recent simulation models of magnetised interstellar medium, including the cr gas describ... | galactic magnetic fields, cosmic rays and winds |
we present energetic particle measurements made at voyager 2 (helioradius 119 au, lat s32°, long 218°) in the heliosheath and at voyager 1 (helioradius 144 au, lat n35°, long 175°) in the local interstellar medium. data are from the lecp instruments on the two spacecraft during mainly the 2017-18 period. voyager 2 is n... | recent energetic particle activity at voyagers 1 and 2 |
measurements of the growth of cosmic structure from galaxy cluster surveys are one of the most powerful and promising cosmological probes currently available. while the fundamental observation is the number of clusters detected as a function of redshift with a given survey observable (e.g. x-ray luminosity, sunyaev-zel... | optimized cluster cosmology with the planck satellite |
star-forming galaxies are the first extragalactic sources whose total emission, or at least a large amount of it, comes from the cosmic rays interactions accelerated by shock fronts in a young stellar population environment but not from the active galactic nuclei. a strong evidence of this fact is the quasi-linear corr... | galaxias con formación estelar activa como emisores de radiación gamma |
galactic cosmic rays are observed at pev energies, so at least a few sources that accelerate to these energies are expected to exist. however, only one such source has been identified: the galactic center. since one of the signatures of a pevatron is a hadronic, hard spectrum that extends without any apparent spectral ... | pevatron candidates in the first 30 months of hawc data |
voyager 1 (v-1) crossed the heliopause in 2012 august, gathering measurements of particle flux as a function of time. with this data, heliophysicists have observed anisotropy in the flux of galactic cosmic rays (gcrs); following the st. patrick solar event in 2013 march, they calculated small increases in the flux of h... | a study of cosmic rays around the surface of the heliopause |
post-pericenter mergers of galaxy clusters may provide a unique window into the behavior of dark matter by acting as "dark matter colliders." mergers may also play a role in the evolution of cluster member galaxies and other astrophysical processes such as cosmic ray acceleration. to quantify these connections, we need... | dynamics of merging galaxy clusters: what can simulated analogs tell us? |
we present evidence for jets from the nearby pulsar, b2224+65, based on three epochs of chandra x-ray observations, separated by 6 years from each other. this relatively slow rotating pulsar is well known for its extreme velocity of proper motion and associated "guitar"-shaped optical nebula in the opposite direction. ... | energetic x-ray-emitting jets from the fast-moving middle-aged pulsar b2224+65 |
recent very high energy observations of the galactic centre region performed by h.e.s.s. revealed the presence of a powerful pevatron. this is the first of such objects detected, and its most plausible counterpart seems to be associated to sgr a*, the supermassive black hole in the centre of our galaxy. the implication... | acceleration of particles up to pev energies at the galactic centre |
high-energy particles enter the solar atmosphere from galactic or solar sources, producing gamma-ray "albedo'' radiations. these emissions come from the quiet sun and from the large-scale corona, as well as from the vicinity of flares, and have been observed across a wide range of photon energies (mev to gev). the inte... | cosmic rays across the rainbow bridge: particle interactions in a magnetized plasma atmosphere |
the supernova remnant (snr) w49b originated from a core-collapse supernova that occurred few thousands years ago, and subsequently evolved into a mixed-morphology remnant, which is interacting with molecular clouds (mc). snr/mc associations are particularly interesting for probing the acceleration of hadrons in snrs an... | observation of the w49b supernova remnant with fermi-lat and h.e.s.s. |
the signatures of laser wakefields have become increasingly important in recent years due to the invention of a novel laser compression technique that may enable the creation of single cycle x-ray pulses. this x-ray driver may be able to utilize solid density targets to create acceleration gradients of up to tev/cm. on... | laser wakefield signatures: from gas plasma to nanomaterials |
i begin this study by presenting an overview of the theory of magnetohydrodynamics and the necessary conditions to justify the fluid treatment of a plasma. upon establishing the fluid description of a plasma we move on to a discussion of magnetohydrodynamics in both the ideal and hall regimes. this framework is then ex... | multi-fluid problems in magnetohydrodynamics with applications to astrophysical processes |
cosmic rays represent only about a billionth of the interstellar gas in galaxies by number, but their energy density is equivalent to that of the thermal gas, although virtually collisionless, they exchange energy and momentum with the thermal gas through their coupling to the interstellar magnetic field, thus playing ... | maxwell prize: the basis for cosmic ray feedback: written on the wind |
in a growing number of galaxy clusters diffuse elongated radio sources have been found, so-called radio relics. these megaparsec relics are usually located in the low-density outskirts of merging clusters. the existence of these radio sources implies the presence of relativistic particles and magnetic fields in the int... | probing the physics of particle acceleration in dilute cosmic plasmas |
the origin of cosmic rays remains a mystery, even over 100 years since their discovery. neutron stars (nss) are considered textbook cases of particle acceleration sites in our galaxy, but many unresolved numerical problems remain. searches for new acceleration sites are crucial for astrophysics. the magnetized white dw... | summary of the session, white dwarf pulsars and rotating white dwarf theory |
in recent years, the detection of star forming galaxies at gev and tev energies by fermi and cherenkov (h.e.s.s. y veritas) observatories, respectively, has opened a new era for the study of the cosmic-ray population of galaxies. the fermi survey is still small, so far just five galaxies outside the local group have be... | emisión de altas energías de galaxias con fomación estelar activa |
the grapes-3 experiment is a compact, high density extensive air shower (eas) array of ∼ 400 scintillator detectors operating in conjunction with a 560 m2 tracking muon telescope with a threshold of eμ > 1 gev. it is being operated in ooty, india since 1 january 2000. the implementation of precise corrections for th... | a review of the recent results from the grapes-3 experiment |
the bulk of the dark matter in the galaxy is believed to have velocity of order several hundred km/s. however, it has recently been shown that cosmic ray collisions with dark matter may accelerate a small fraction of the galactic dark matter to much higher velocities. this boosted dark matter would transfer far more en... | constraining dark matter with cosmic ray interactions |
we present the high altitude water cherenkov (hawc) observatory's first catalog of gamma-ray sources emitting at the highest energies (above 50 tev and 100 tev). hawc consists of an array of 300 water cherenkov detectors located in puebla, mexico and is well-suited to performing all-sky surveys due to its high duty cyc... | the hawc observatory's first catalog of sources emitting above 50 tev and 100 tev |
constraints on galactic cosmic-ray origins from elemental composition measurements r.a. mewaldt1, w.r. binns2, e.r. christian3, a.c. cummings1, g.a. de nolfo3, m.h. israel2, k.a. lave2 r.a. leske1, e.c. stone1, t.t. von rosenvinge3, m.e. wiedenbeck41california institute of technology, pasadena, ca 91125 usa2washington ... | constraints on galactic cosmic-ray origins from elemental composition measurements |
we report on variations in the intensities and angular distributions of energetic (>28 kev) ions and (>22 kev) electrons, and > 213 mev galactic cosmic ray protons, all measured during the passage of voyager 2 from the heliosheath into the local interstellar medium. intensity drops of low-energy heliosheath io... | voyager 2 measurements of energetic particles across the heliopause |
on december 8, 2012 the supertiger (super trans-iron galactic element recorder) instrument was launched from williams field, antarctica on a long-duration balloon flight that lasted 55 days and maintained a mean altitude of 125,000 feet. supertiger measured the relative abundances of galactic cosmic-ray (gcr) nuclei wi... | supertiger abundances of galactic cosmic rays for the charge interval z=41-56 |
star formation proceeds inefficiently in galaxies for reasons that remain under debate. in the local ism it is known that the cosmic rays (crs) provide a significant fraction of total ism pressure and therefore contribute to hydrostatic balance. here we develop a model for the dynamical effect of crs, directly accelera... | cosmic ray feedback in star-formation and implications for gamma-ray emission from starbursts |
the intra-cluster medium (icm), the x-ray emitting hot plasmas associated with individual clusters of galaxies, is the most dominant form of all known cosmic baryons. confined by gravity in a hydrostatic manner, the icm is considered to be free from most of instabilities, except the radiative thermal instability on lar... | how the hot plasmas in clusters of galaxies are thermally stabilized |
understanding the complete nature of galactic sources that accelerate cosmic rays up to $10^{15}$ ev energy (galactic pevatrons) is still an unsolved problem in high-energy astrophysics. although supernova remnants have long been considered as the best candidates for galactic pevatrons, a clear association of snrs with... | veritas and hawc observations of unidentified source lhaaso j2108+5157 |
a well-known paradigm about the origin of galactic cosmic rays (crs) is that these high-energy particles are accelerated in the process of diffusive shock acceleration (dsa) at collisionless shocks (at least up to the so-called "knee"energy of $10^{15}$ ev). knowing the details of injection of electrons, protons and he... | diffusive shock acceleration of cosmic rays - quasi-thermal and non-thermal particle distributions |
star-forming galaxies (sfgs) have been established as an important source population in the extra-galactic $\gamma$-ray background (egb). their intensive star-formation creates an abundance of environments able to accelerate particles, and these build-up a rich sea of cosmic rays (crs). above gev energies, cr protons c... | cosmic ray calorimetry in star-forming galaxy populations and implications for their contribution to the extra-galactic $\\gamma$-ray background |
anisotropic diffusion is imperative in understanding cosmic ray diffusion across the galaxy, the heliosphere, and the interplay of cosmic rays with the galactic magnetic field. this diffusion term contributes to the highly stiff nature of the cosmic ray transport equation. to conduct numerical simulations of time-depen... | efficient numerical methods for anisotropic diffusion of galactic cosmic rays |
organic features lead to two distinct types of class 0/i low-mass protostars: hot corino sources, and warm carbon-chain chemistry (wccc) sources. some observations suggest that the chemical variations between wccc sources and hot corino sources are associated with local environments, as well as the luminosity of protos... | chemical differences among collapsing low-mass protostellar cores |
galaxy clusters are the largest and most massive gravitationally bound structures known in the universe. cosmic-ray (cr) hadrons accelerated at structure formation shocks and injected by galaxies, are confined in galaxy clusters where they accumulate for cosmological times. the presence of diffuse synchrotron radio emi... | constraints on the cosmic ray cluster physics from a very deep observation of the perseus cluster with magic |
the local interstellar energy spectra of galactic cosmic rays down to a few mev/nucleon were directly measured in the experiment on the board of the voyager 1 spacecraft. we suggest interpretation of these data based on our models of cosmic ray acceleration in supernova remnants and the diffusion in galactic wind where... | interpretation of voyager 1 data on low energy cosmic rays in galactic wind model |
supernova remnants (snrs) are nowadays considered as the favoured sources of galactic cosmic rays. when accelerated protons encounter the interstellar material they produce neutral pions, which in turn decay into gamma rays. the observation of the g-ray emission from snrs therefore is a compelling way to identificate a... | fermi-lat analysis of extended supernova remnants with the new pass 8 data |
we propose that the recently observed diffuse neutrinos by icecube with energies above 1 pev might have originated from sagittarius $\mathrm{a}^{\star}$ located in the galactic disk. this implies that the astrophysical settings of sagittarius $\mathrm{a}^{\star}$ need to accelerate hadronic cosmic rays to energies of $... | sagittarius $\\mathrm{a}^{\\star}$ as a plausible source candidate for pev neutrinos |
galaxy clusters represent the last step of the formation of large-scale structures in the universe. they are both useful cosmological probes and unique astrophysical laboratories. the clusters grow by accretion of surrounding structures and from the merging of subclusters, in very energetic events, eventually forming a... | search for diffuse gamma-ray emission from galaxy clusters with the cherenkov telescope array |
detailed modelling of the evolution of neutral hydrogen in the intergalactic medium during the epoch of reionization, $5 \leq z \leq 20$, is critical in interpreting the cosmological signals from current and upcoming 21-cm experiments such as low-frequency array (lofar) and the square kilometre array (ska). numerical r... | pyc$^2$ray: a flexible and gpu-accelerated radiative transfer framework for simulating the cosmic epoch of reionization |
the knee of cosmic ray spectra reflects the maximum energy accelerated by galactic cosmic ray sources or the limit to the ability of galaxy to bind cosmic rays. the measuring of individual energy spectra is a crucial tool to ascertain the origin of the knee. the extensive air shower of cosmic rays in the knee energy re... | properties of secondary components in extensive air shower of cosmic rays in knee energy region |
a new parametrization of the phenomenological hubble parameter is proposed to explore the issue of the cosmological landscape. the constraints on model parameters are derived through the markov chain monte carlo (mcmc) method by employing a comprehensive union of datasets such as 34 data points from cosmic chronometers... | governing accelerating universe via newly reconstructed hubble parameter by employing empirical data simulations |
kepler's supernova remnant (snr) which is produced by the most recent naked-eye supernova in our galaxy is one of the best studied snrs, but its gamma-ray detection has eluded us so far. observations with modern imaging atmospheric cherenkov telescopes (iact) have enlarged the knowledge about nearby snrs with ages youn... | deep observations of kepler's snr with h.e.s.s. |
although the existence and importance of magnetic fields and cosmic rays are widely recognized in the current universe, their origins in the early universe are not unrevealed yet. motivated by the recent studies that suggest the acceleration of cosmic rays in the supernova remnants of first stars, we propose a new gene... | a new magnetic field generation mechanism induced by streaming cosmic rays |
the galactic center excess (gce), one of the most remarkable discoveries by fermi-lat, has prompted extensive exploration over the past decade, often attributed to dark matter or millisecond pulsars. this work proposes a novel interpretation on the origin of the gce, focusing on the observed spectral shape. protons are... | gluon condensation: from nucleon to galactic center |
supernova remnants (snrs) have been considered as the dominant contributors to galactic cosmic rays (crs). however, the relation between high-energy particles accelerated in snrs and cosmic rays observed at the earth remains obscure. we fit the spectral energy distributions of 35 snrs with a simple one-zone emission mo... | evolution of high-energy particle distribution in supernova remnants |
we present the discovery of ringlike diffuse radio emission structures in the peripheral regions of the bullet cluster 1e 0657$-$55.8. ring formations are spanning between 1--3 mpc away from the center of the cluster, significantly further away from the two already reported relics. integrated fluxes of four of the sub-... | `rings' of diffuse radio emission surrounding the bullet cluster |
recent observations of the diffuse galactic gamma-ray emission by the fermi-lat satellite have shown significant deviations from models which assume the same diffusion properties for cosmic rays (cr) throughout the galaxy. we explore the possibility that a fraction of this diffuse galactic emission could be due to hadr... | contribution to diffuse gamma-ray emission coming from self-confined crs around their galactic sources |
we apply the ultrarelativistic generalized lorentzian quasi-equilibrium thermodynamic energy distribution to the energy spectrum of galactic cosmic ray fluxes. the inferred power law slopes contain a component which evolves with cosmic ray energy in steps of thirds, resembling the sequence of structure functions in ful... | ultrarelativistic generalized lorentzian thermodynamics and the differential cosmic ray energy flux |
trace charge imbalances can explain puzzling cosmological observations such as the large `missing' fraction of electrons in cosmic rays and their contrast to the charge-neutral solar wind, the extreme energy sources that sustain pulsars, quasars, galactic jets and active galactic nuclei (agn), the origin and nature of ... | cosmological implications of trace-charged dark matter |
studying gamma-ray emission by galactic objects is key to understanding the origins and acceleration mechanisms of galactic cosmic ray electrons and hadrons. the hawc observatory provides an unprecedented view of the gamma-ray sky at tev energies and is particularly suited for the study of galactic objects. however, th... | joint likelihood fits for the study of galactic objects with hawc |
despite centuries of rigorous theoretical and observational research, the origin and acceleration mechanism of galactic cosmic rays (gcrs) remain a mystery. in 1949, fermi proposed a diffusive shock acceleration model that includes a prominent mechanism for gcr acceleration. however, observational evidence, on the othe... | observational validation of cosmic ray acceleration hypothesis |
cool outflows are now commonly observed in galaxies, but their physical origin and driving mechanism remain unclear. active galactic nucleus (agn) feedback can potentially accelerate cool galactic outflows via cosmic rays (cr) and radiation pressure on dust. here we investigate the relative importance of cr and radiati... | agn cool feedback and analogy with x-ray binaries: from radiation pressure to cosmic ray-driven outflows |
cosmic ray electron (cre) acceleration and cooling are important physical processes in astrophysics. we develop an approximative framework to treat cre physics in the parallel smoothed particle hydrodynamics code gadget-3. in our methodology, the cre spectrum of each fluid element is approximated by a single power-law ... | modelling cosmic ray electron physics in cosmological smoothed particle hydrodynamics simulation |
recent measurements revealed the presence of several features in the cosmic ray spectrum. in particular, the proton and helium spectra exhibit a spectral hardening at $\approx$ 300 gv and a spectral steeping at $\approx$ 15 tv, followed by the well known knee-likefeature at $\approx$ 3 tv. the spectra of heavier nuclei... | on the origin of the spectral features observed in the cosmic ray spectrum |
clusters of galaxies are the most massive virialized structures in the universe. the microphysical properties of the intracluster plasma can affect dynamical processes over an enormous range: from the feedback of active galactic nuclei to shock acceleration in merging clusters. all the major cosmological simulations as... | astro2020 science white paper: a unification of the micro and macro physics in the intracluster medium of nearby clusters |
supernova remnants (snrs) that exhibit x-ray spectra dominated by synchrotron radiation are crucial laboratories for the study of cosmic-ray acceleration by this class of sources. however, despite the discovery of synchrotron x-ray emission from the archetypal source sn 1006 over two decades ago, the number of galactic... | l-band and p-band observations of galactic supernova remnants with synchrotron x-ray-dominated spectra |
the galactic supernova remnant (snr) g28.6-0.1 belongs to the remarkable class of snrs that exhibit x-ray spectra that are dominated by synchrotron radiation emitted by extremely energetic accelerated cosmic-ray particles. detailed spatially resolved spectroscopic studies of these snrs are crucial in yielding insights ... | an x-ray and radio analysis of the peculiar galactic supernova remnant g28.6-0.1 |
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