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the improved understanding of the interlinked atmospheric and terrestrial hydrological processes requires concerted and compartment-crossing observation and -modeling efforts. through the tereno prealpine observatory, located in the southern bavarian region of germany, comprehensive technical infrastructure is being es... | the tereno-prealpine observatory: a research infrastructure for hydrometeorological observation and -modeling across compartments and scales |
the high-energy telescope (het) for the epi-hi experiment on the parker solar probe (psp) is designed to measure the composition of solar-energetic-particle (sep), interplanetary, and galactic cosmic ray (cgr) ions with 1 ? z ? 30 from 10-20 mev/nuc up to several hundred mev/nuc, as well as electrons from 0.5 to 8 mev.... | solar gamma ray and neutron science with the epi-hi/het telescope on psp |
the measurement of the isotopic composition of cosmic rays (crs) provides essential insights into the understanding of the origin and propagation of these particles, namely the cr source spectra, the propagation processes and the galactic halo size. the alpha magnetic spectrometer (ams-02), a cr experiment operating ab... | iterative-bayesian unfolding of cosmic-ray isotope fluxes measured by ams-02 |
critical need for ldms techniques: laser desorption mass spectrometry (ldms) enables 2d and/or 3d chemical imaging of organic and inorganic analytes, supporting focused research objectives as well as discovery-based science. many minerals and (aromatic) organics effectively absorb uv radiation, and photon energies of u... | laser desorption mass spectrometry (ldms) with an orbitrap mass analyzer: a historical perspective and future projection |
we consider the kinematic stage of evolution of magnetic field advected by turbulent hydrodynamic flow. we use a generalization of the kazantsev-kraichnan model to investigate time irreversible flows. in the viscous range of scales, the infinite-time limit of the spectrum is a power law, but its slope is more flat than... | magnetic energy spectrum produced by turbulent dynamo: effect of time irreversibility |
results from a numerical study of fluctuation dynamo in a collisionless, weakly magnetized plasma are presented. the key difference between this dynamo and its magnetohydrodynamic (mhd) counterpart is the adiabatic production of magnetic-field-aligned pressure anisotropy by the amplification of a weak seed field. this,... | fluctuation dynamo in a collisionless, weakly magnetized plasma |
relativistic jets from supermassive black holes are among the most powerful and luminous astrophysical systems in universe. we propose that the open magnetic field lines through the black hole, which drive a strongly magnetized jet, may have their polarity reversing over time scales related to the growth of the magneto... | radiation signatures from striped blazar jet |
we have obtained a smooth time series for the electric vector position angle (evpa) of the blazar oj 287 at centimeter wavelengths, by making ±nπ adjustments to archival values from 1974 to 2016. the data display rotation reversals in which the evpa rotates counterclockwise for ∼180° and then rotates clockwise by a sim... | reversals in the direction of polarization rotation in oj 287 |
context. a convenient representation of the structure of the large-scale galactic magnetic field is required for the interpretation of polarization data in the sub-mm and radio ranges, in both the milky way and external galaxies.aims: we develop a simple and flexible approach to construct parametrised models of the lar... | a physical approach to modelling large-scale galactic magnetic fields |
the grand-design face-on spiral galaxy m 51 is an excellent laboratory for studying magnetic fields in galaxies. due to wavelength-dependent faraday depolarization, linearly polarized synchrotron emission at different radio frequencies yields a picture of the galaxy at different depths: observations in the l-band (1-2 ... | the magnetized disk-halo transition region of m 51 |
the milky way is one of the very few spiral galaxies known to host large-scale magnetic field reversals. the existence of the field reversal in the first galactic quadrant near the sagittarius spiral arm has been well established, yet poorly characterized due to the insufficient number of reliable faraday depths (fds) ... | the complex large-scale magnetic fields in the first galactic quadrant as revealed by the faraday depth profile disparity |
a study of collisionless external shocks in gamma-ray bursts is presented. the shock structure, electromagnetic field, and process of electron acceleration are assessed by performing a self-consistent 3d particle-in-cell simulation. in accordance with hydrodynamic shock systems, the shock consists of a reverse shock (r... | collisionless weibel shocks and electron acceleration in gamma-ray bursts |
rotation measure (rm) synthesis maps of ngc 4631 show remarkable sign reversals with distance from the minor axis in the northern halo of the galaxy on kpc scales. to explain this new phenomenon, we solve the dynamo equations under the assumption of scale invariance and search for rotating logarithmic spiral solutions.... | evolving galactic dynamos and fits to the reversing rotation measures in the halo of ngc 4631 |
we studied the magnetic field structures and dynamics of magnetized multiphase gas on parsec scales around supermassive black holes by using global 3d magnetohydrodynamics (mhd) simulations. we considered the effect of radiative cooling and x-ray heating due to active galactic nuclei (agns). the gas disk consists of a ... | multiphase circumnuclear gas in a low-β disk: turbulence and magnetic field reversals |
aims: we present rotation measures (rm) of the diffuse galactic synchrotron emission from the canadian galactic plane survey (cgps) and compare them to rms of extragalactic sources in order to study the large-scale reversal in the galactic magnetic field (gmf).methods: using stokes q, u and i measurements of the galact... | three-dimensional structure of the magnetic field in the disk of the milky way |
we give a selection of exact dynamos in axial symmetry on a galactic scale. these include some steady examples, at least one of which is wholly analytic in terms of simple functions and has been discussed elsewhere. most solutions are found in terms of special functions, such as associated lagrange or hypergeometric fu... | exact axially symmetric galactic dynamos |
we report the earliest ever detection of optical polarization from a grb forward shock (grb 141220a), measured $129.5{-}204.3\,$s after the burst using the multicolour ringo3 optical polarimeter on the 2-m fully autonomous robotic liverpool telescope. the temporal decay gradient of the optical light curves from $86\,$ ... | coherence scale of magnetic fields generated in early-time forward shocks of grbs |
we study the evolution of galactic magnetic fields using 3d smoothed particle magnetohydrodynamics (spmhd) simulations of galaxies with an imposed spiral potential. we consider the appearance of reversals of the field, and amplification of the field. we find that magnetic field reversals occur when the velocity jump ac... | magnetic field evolution and reversals in spiral galaxies |
the propagation of active galactic nucleus jets depends both on the environment into which they propagate and on their internal structure. to test the impact that different magnetic topologies have on the observable properties of radio galaxies on kpc scales, we conducted a series of magnetohydrodynamic simulations of ... | a numerical study of the impact of jet magnetic topology on radio galaxy evolution |
in this work, we interpret and discuss the time variable rotation measure (rm) found, for the first time over a 1-yr period, in the core region of a blazar. these results are based on a 1-yr, multifrequency (15, 24 and 43 ghz) very long baseline array (vlba) monitoring of the tev blazar markarian 421 (mrk 421). we inve... | interpreting the time variable rm observed in the core region of the tev blazar mrk 421 |
in this paper we study numerically large-scale magnetic field evolution and its enhancement in gaseous disks of spiral galaxies. we consider a set of models with the various spiral pattern parameters and the initial magnetic field strength with taking into account gas self-gravity and cooling and heating processes. in ... | global enhancement and structure formation of the magnetic field in spiral galaxies |
the chang-es (continuum halos in nearby galaxies) survey of 35 nearby edge-on galaxies is revealing new and sometimes unexpected and startling results in their radio continuum emission. the observations were in wide bandwidths centred at 1.6 and 6.0 ghz. unique to this survey is full polarization data showing magnetic ... | chang-es: xviii—the chang-es survey and selected results |
the early optical afterglow emission of several gamma-ray bursts (grbs) shows a high linear polarization degree (pd) of tens of percent, suggesting an ordered magnetic field in the emission region. the light curves are consistent with being of a reverse shock (rs) origin. however, the magnetization parameter, σ, of the... | magnetized reverse shock: density-fluctuation-induced field distortion, polarization degree reduction, and application to grbs |
we explore the effect of the magnetic prandtl number pm on energy and dissipation in fully resolved direct numerical simulations of steady-state, mechanically forced, homogeneous magnetohydrodynamic turbulence in the range 1 /32 <pm <32 . we compare the spectra and show that if the simulations are not fully resol... | fully resolved array of simulations investigating the influence of the magnetic prandtl number on magnetohydrodynamic turbulence |
to pinpoint the peak location of the synchrotron total intensity emission in a spiral arm, we use a map of the spiralarm locations (from the observed arm tangent). thus in a typical spiral arm in galactic quadrant i, we find the peak of the synchrotron radiation to be located about 220 +/-40 pc away from the inner arm ... | superposing the magnetic spiral structure of the milky way, on the stellar spiral arms - matching the unique galactic magnetic field reversal zone with two galactic spiral arm segments |
the geomagnetic field (gmf) is one of the environmental stimuli that plants experience continuously on earth; however, the actions of the gmf on plants are poorly understood. here, we carried out a time-course microarray experiment to identify genes that are differentially regulated by the gmf in shoot and roots. we al... | differential root and shoot magnetoresponses in arabidopsis thaliana |
we simulate the evolution of supernova remnants (snrs) in a strong magnetic field. usually, supernovae explode in a normal interstellar medium with magnetic field of no more than 50 μg, which has been well studied. however, the surrounding magnetic field will be much stronger in some situations, such as in a galactic c... | how does a strong surrounding magnetic field influence the evolution of a supernova remnant? |
at the present time, the induction of several microgauss in large-scale fields of the galaxy has been repeatedly confirmed. there are numerous arguments in favor of the fact that the magnetic field exhibits so-called reversals associated with a direction change from one region to another. such configurations are allowe... | structure and features of the galactic magnetic-field reversals formation |
magnetic fields play such essential roles in star formation as transporting angular momentum and driving outflows from a star-forming cloud, thereby controlling the formation efficiency of a circumstellar disc and also multiple stellar systems. the coupling of magnetic fields to the gas depends on its ionization degree... | ionization degree and magnetic diffusivity in star-forming clouds with different metallicities |
magnetic fields permeate the universe on all scales and play a key role during star formation. we study the evolution of magnetic fields around a massive metal-free (population iii) star at z ∼ 15 during the growth of its h ii region and subsequent supernova explosion by conducting three cosmological magnetohydrodynami... | amplification of magnetic fields in a primordial h ii region and supernova |
inflation has long been considered the best way to produce primordial large-scale magnetic fields. to achieve fields strong enough to seed the galactic dynamo, most of the mechanisms operate outside conventional electromagnetic theory. the latter is typically restored after the end of the de sitter phase. breaking away... | relaxing the limits on inflationary magnetogenesis |
we report the discovery of optical and x-ray synchrotron emission from the brighter radio jet in galaxy ngc 7385 using data from hst and chandra. the jet has a projected length of 5 kpc and a similar morphology to other known optical jets in low-power radio galaxies. we also report a strong jet-cloud interaction which ... | discovery of an optical and x-ray synchrotron jet in ngc 7385 |
this paper reviews observational evidence obtained to date about the overall structure of the magnetic fields in the jets of active galactic nuclei (agn). because they are sensitive to the line-of-sight magnetic-field component, faraday rotation observations of agn jets provide an effective tool for searching for toroi... | the origin and structure of the magnetic fields and currents of agn jets |
the superfine structure of the active region of the radio galaxy m 87 has been investigated at millimeter and centimeter wavelengths. a disk, a core, a jet, and a counterjet have been identified. the disk is inclined to the plane of the sky at an angle of 60° toward the jet. we show that the surrounding thermal plasma ... | kinematics of the nucleus of the radio galaxy m 87 |
we studied large-scale magnetic field reversals of a galaxy based on a magnetic vector map of ngc6946. the magnetic vector map was constructed based on the polarization maps in the c and x bands after the determination of the geometrical orientation of a disk with the use of an infrared image and the velocity field, ac... | magnetic field vector structure of ngc6946 |
in this conference contribution, we discuss and interpret the time variable rotation measure (rm) detected in the core region of the tev blazar markarian 421 (mrk 421). we monitored mrk 421 during 2011 with one observing run per month at 15, 24, and 43 ghz with the american very long baseline array. we explore the poss... | on the time variable rotation measure in the core region of markarian 421 |
derived here is a more conceptually intuitive means of interpreting magnetic-field diagnostics from circularly polarized lines in a wide array of astrophysical applications. the method applies to individual “stokes v” profile snapshots and complements standard zeeman doppler imaging techniques by providing the explicit... | the antiderivative of the stokes v polarization profile. i. a simple procedure for magnetic field characterization |
> zeldovich's stretch-twist-fold (stf) dynamo provided a breakthrough in conceptual understanding of fast dynamos, including the small-scale fluctuation dynamos. we study the evolution and saturation behaviour of two types of generalized baker's map dynamos, which have been used to model zeldovich's stf dynamo proce... | saturation of zeldovich stretch-twist-fold map dynamos |
reverse shock (rs) emission can be used to probe the properties of the relativistic ejecta, especially the degree of magnetization σ, in gamma-ray burst (grb) afterglows. however, there has been confusion in the literature regarding the physical condition for the rs formation, and the role of magnetic fields in the rs ... | reverse shock forming condition for magnetized relativistic outflows: reconciling theories and simulations |
conceptualizing planetary habitability depends on understanding how living organisms originated and what features of environments are essential to foster abiogenesis. estimates of the abundance of life's building blocks are confounded by incomplete knowledge of the role of chirality and racemization in organic compound... | galactic distribution of chirality sources of organic molecules |
it is widely believed that, in active galactic nuclei (agns), a supermassive black hole with an accretion disk is surrounded by an optically and geometrically thick torus at sub-parsec scale. however, it is not clear how the mass supply is toward the central engine caused and how it is related with the internal structu... | magneto rotational instability in magnetized agn tori |
we present a method for determining the directions of magnetic-field vectors in a spiral galaxy using two synchrotron polarization maps, an optical image, and a velocity field. the orientation of the transverse magnetic field is determined with a synchrotron polarization map of a higher-frequency band, and the 180°-amb... | magnetic-field vector maps of nearby spiral galaxies |
here we present detailed analysis of the distinct x-ray emission features present within the eastern radio lobe of the pictor a galaxy, around the jet termination region, utilizing the data obtained from the chandra x-ray observatory. various emission features have been selected for the study based on their enhanced x-... | complex structure of the eastern lobe of the pictor a radio galaxy: spectral analysis and x-ray/radio correlations |
astrophysical accretion flows are associated with energetic emission of radiation and outflows (winds and jets). extensive observations of these two processes in x-ray binary outbursts are available. a convincing understanding of their dynamics remains, however, elusive. the main agent that controls the dynamics is bel... | generation and transport of magnetic flux in accretion–ejection flows |
magnetic field is an essential ingredient of the interstellar medium of galaxies. in particular, an accurate characterisation of the magnetic field strength and structure of the milky way is crucial for complete understanding of many galactic astrophysical processes. the faraday rotation effect can be exploited to reve... | new insights into the milky way magnetic fields through radio broadband spectro-polarimetry |
we present a study of the milky way halo magnetic field, determined from observations of faraday rotation measure (rm) of extragalactic radio sources (egs) in galactic longitude range 100°-117° within 30° of the galactic plane. we find negative median rms in both the northern and southern galactic hemispheres for |b|&g... | magnetic fields in the milky way halo |
cluster merger events drive shocks in the intra-cluster plasma and activate non-thermal phenomena such as particle acceleration, magnetic field amplification, and turbulence. however, details of these processes are not well known because of a lack of observations. the known examples of merging clusters are mostly in la... | observation of a nearby early merging cluster of galaxies, ciza j1358.9-4750: new born shocks in the icm |
the characteristic reversal scale of amplified magnetic fields during several stages of the fluctuation dynamo is set by the plasma resistivity. in weakly collisional high-beta plasmas, such as in the intracluster medium of galaxy clusters, the nature of this resistivity is likely to be influenced by larmor-scale kinet... | electrical resistivity of collisionless, high-beta plasmas |
context. in soft x-rays, the monogem ring is an object with a diameter of 25° located in the galactic anti-centre. it is believed to be a faint, evolved, local supernova remnant. the ring is also visible in the far-ultraviolet, and a few optical filaments are related. it is not seen at radio wavelengths, as other large... | long, depolarising hα-filament towards the monogem ring |
our mhd numerical calculations provide results for a three-dimensional model of barred galaxies involving a cosmic-ray driven dynamo process that depends on star formation rates. we applied global 3d numerical calculations of a cosmic-ray driven dynamo in barred galaxies with different physical input parameters such as... | 3d evolution of barred galaxies based on the cosmic-ray driven dynamo |
multiferroics are a broad class of materials, which couple multiple ferroic ordering parameters into a single composite--e.g., coupling ferroelectric and ferromagnetic materials. the key feature of multiferroic composites is the ability to control the magnetic (dipole) moments of the composite via an applied electric (... | controlling the magnetic state of nickel nanocrystal in granular multiferroic composites |
some of the galaxies have regular magnetic fields which are generated by the dynamo mechanism. it is based on joint action of differential rotation and alpha-effect. for some objects it is possible to have the field reversal, when it has opposite directions in different regions of galaxy. the reversals can be described... | evolution of the magnetic field reversals in galaxies |
the anomalous magnetic moment of the electron makes it weakly paramagnetic. schwinger predicted that in fields above 1e13 g, this behavior reverses and the electron becomes diamagnetic, but this prediction has recently been challenged. an alternate scenario has been proposed in which the electron's paramagnetism contin... | jets from paramagnetic electrons in superstrong fields |
while the basic laws of physics seem time-reversal invariant, our understanding of the apparent irreversibility of the macroscopic world is well grounded in the notion of entropy. because astrophysics deals with the largest structures in the universe, one expects evidence there for the most pronounced entropic arrow of... | symmetry and the arrow of time in theoretical black hole astrophysics |
faraday rotation measure synthesis is a powerful tool that has been employed in the past decade when studying line-of-sight magnetic fields of galactic and extragalactic sources. rotation measures, which are sensitive to the strength and direction of fields in an intervening medium between the source and observer, were... | faraday rotation measure synthesis of ugc 10288 |
various abrupt climate events have been reported during the last glacial period, but their regional expressions and causes remain complex and not fully understood largely due to lack of high-resolution paleoclimate records. in this study, a high-resolution loess sequence is presented from north china which is significa... | orbitally and galactic cosmic forced abrupt climate events during the last glacial period |
we model the large-scale galactic magnetic fields, including a spiral arm compression to generate anisotropic turbulence, by comparing polarized synchrotron and thermal dust emission. preliminary results show that in the outer galaxy, the dust emission comes from regions where the fields are more ordered than average w... | multiwavelength magnetic field modeling |
the concept of substrate inhibition to prevent its phosphorylation has potential in drug discovery and is envisioned to treat the autoimmune disorder multiple sclerosis (ms). glia maturation factor-β (gmf-β) ser83 phosphorylation by protein kinase a (pka) is pivotal in the activation of gmf-β-p38mapk-nfκb biochemical p... | substrate specific inhibitor designed against the immunomodulator gmf-beta reversed the experimental autoimmune encephalomyelitis |
conceptualizing planetary habitability depends on understanding how living organisms originated and what features of environments are essential to foster abiogenesis. estimates of the abundance of life's building blocks are confounded by incomplete knowledge of the role of chirality and racemization in organic compound... | galactic distribution of chirality sources of organic molecules |
the high-energy catalogs of the fermi large area telescope contain more than a thousand gamma-ray detections that have never been connected to a source. some of these gamma rays could stem from very exotic objects: bow shocks of runaway stars.an artists rendering of a blazar. these ultra-luminous objects associated wit... | when stars run away |
we report on the results of an analysis of the hydrodynamic properties of the supernova remnant g156.2+5.7. the models of truelove and mckee (1999) are constrained by the observed amount of thermal x-ray emission, the measured temperature of the forward-shocked electrons, the inferred location of the reverse shock, and... | g156.2+5.7: sn 1006's older cousin |
active galactic nuclei (agn) play an integral role in galaxy formation and evolution by influencing galaxies and their environments through radio jet feedback. historically, interpreting observations of radio galaxies and quantifying radio jet feedback has been challenging due to degeneracies between their physical par... | faraday rotation as a probe of radio galaxy environment in rmhd agn jet simulations |
the very-high-energy gamma-ray emission observed from a number of supernova remnants (snrs) indicates particle acceleration to high energies at the shock of the remnants and a potentially significant contribution to galactic cosmic rays. it is, however, difficult to determine whether protons (through hadronic interacti... | impact of a circumstellar medium on particle acceleration in supernova remnants |
detailed energy spectra of cosmic rays (crs) measured close to earth provide powerful constraints on the physics of their transport in the milky way. these spectra can be modeled reasonably well assuming diffusive propagation in the galaxy with a prescribed power-law energy dependence. however, the microphysical origin... | on the hunt for a new theory of cosmic ray transport |
lidar systems in applications such as autonomous mobile robots, drones, vehicles, and other commercial applications that demand compact, low-cost, and dynamic scanning will inevitably turn to mems mirrors as the beam-steering component. beam scanning-based lidar architectures have a significant advantage as the full po... | comparison of mems mirror lidar architectures |
a possibility of generating a population of cosmic ray particles accelerated in supernovae type ia (snia) remnants in the intracluster medium (icm) is discussed. the presently constrained host-less snia rates in the clusters are found to be sufficient to fill a few hundred kpc region with cosmic ray electrons within th... | role of intracluster supernovae in radio mini-haloes in galaxy clusters |
small-scale turbulent dynamo is responsible for the amplification of magnetic fields on scales smaller than the driving scale of turbulence in diverse astrophysical media. most earlier dynamo theories concern the kinematic regime and small-scale magnetic field amplification. here we review our recent progress in develo... | small-scale turbulent dynamo in astrophysical environments: nonlinear dynamo and dynamo in a partially ionized plasma |
microquasars are neutron star or black hole x-ray binaries with jets. these jets can create bubbles of hot plasma shock ionized that can masquerade as peculiar supernova remnants (snrs) in extragalactic surveys. to see if this is the case in the well-studied spiral galaxy m83, where one microquasar candidate (m83-mq1) ... | a new microquasar candidate in m83 |
we present a third epoch of chandra observations of the type ia large magellanic cloud supernova remnant 0509-67.5. with these new observations from 2020, the baseline for proper-motion measurements of the expansion has grown to 20 yr (from the earliest chandra observations in 2000). we report here the results of these... | an x-ray proper-motion study of the large magellanic cloud supernova remnant 0509-67.5 |
the infrared-to-x-ray (irx) flux ratio traces the relative importance of dust cooling to gas cooling in astrophysical plasma such as supernova remnants (snrs). we derive irx ratios of snrs in the lmc using spitzer and chandra snr survey data and compare them with those of galactic snrs. irx ratios of all the snrs in th... | dust cooling in supernova remnants in the large magellanic cloud |
supernova remnants (snrs) have long been considered the leading candidate sites for the acceleration of cosmic rays within the galaxy through the process of diffusive shock acceleration. the connection between snrs and cosmic rays is supported by the detection of high energy (he; 100 mev to 100 gev) and very high energ... | a detailed study of gamma-ray emission from cassiopeia a using veritas |
we found a simultaneous decrease of the fe-k line and 4.2-6 kev continuum of cassiopeia a with the monitoring data taken by the chandra x-ray observatory in 2000-2013. the flux change rates in the whole remnant are -0.65 ± 0.02% yr-1 in the 4.2-6.0 kev continuum and -0.6 ± 0.1% yr-1 in the fe-k line. in the eastern reg... | multi-year x-ray variations of iron-k and continuum emissions in the young supernova remnant cassiopeia a |
the x-ray source cxo j085201.4-461753 in the few kyr-old vela jr. supernova remnant (snr, g266.2-1.2) belongs to the peculiar class of isolated neutron stars dubbed `central compact objects' (ccos). at variance with the other ccos, which are only detected in the x-rays, cxo j085201.4-461753 has been possibly detected a... | the nature of the infrared counterpart and of the optical nebula associated with the central compact object in vela jr. |
context. the galactic supernova remnant kes 78 is surrounded by dense molecular clouds, whose projected position overlaps with the extended hess γ-ray source hess j1852-000. the x-ray emission from the remnant has recently been revealed by suzaku observations, which have shown indications for a hard x-ray component in ... | xmm-newton observation of the supernova remnant kes 78 (g32.8-0.1): evidence of shock-cloud interaction |
computations of the evolution of the distributions of the size and degree of aromatization of interstellar dust grains, destruction by radiation and collisions with gas particles, and fragmentation during collisions with other grains are presented. the results of these computations are used to model dust emission spect... | the evolution of hydrocarbon dust grains in the interstellar medium and its influence on the infrared spectra of dust |
in the last few years, several experiments have shown that the cosmic ray spectrum below the knee is not a perfect power law. in particular, the proton and helium spectra show a spectral hardening by ∼0.1-0.2 in spectral index at particle energies of ∼ 200-300 gev nucleon-1. moreover, the helium spectrum is found to be... | non-linear acceleration at supernova remnant shocks and the hardening in the cosmic ray spectrum |
supernovae and gamma-ray bursts (grbs) are among the brightest events in the universe. excluding type ia supernovae and short grbs, they are the result of the core collapse of a massive star with material being ejectedwith speeds of several 1000 km/s to nearly the speed of light, and with a neutron star or a black hole... | vlbi of supernovae and gamma-ray bursts |
we report on the likely detection of γ-ray emission from the supernova remnant (snr) kesteven 27 (kes 27). we analyze 5.7 yr fermi large area telescope data of the snr region and find an unresolved source at a position consistent with the radio brightness peak and the x-ray knot of kes 27, which is located in the easte... | supernova remnant kesteven 27: interaction with a neighbor hi cloud viewed by fermi |
we report our independent gev γ-ray study of the young shell-type supernova remnant (snr) kes 73, which harbors a central magnetar, and co-line millimeter observations toward the snr. using 7.6 years of fermi-lat observation data, we detected an extended γ-ray source (“source a”) with centroid on the west of the snr, w... | a study of fermi-lat gev γ-ray emission toward the magnetar-harboring supernova remnant kesteven 73 and its molecular environment |
we carry out 1d hydrodynamical simulations of the evolution of a spherically symmetric supernova remnant (snr) subject to an external radiation field (erf) that influences the cooling and heating rates of the gas. we consider homogeneous media with ambient hydrogen number densities nh, 0 of 0.1 and 1 cm-3 permeated by ... | impact of the erf on the structure and evolution of snrs |
the supernova remnant (snr) candidate g 116.6 - 26.1 is one of the few high galactic latitude (|b| > 15°) remnants detected so far in several wavebands. it was discovered recently in the srg/erosita all-sky x-ray survey and also displays a low-frequency weak radio signature. in this study, we report the first optica... | first optical identification of the srg/erosita-detected supernova remnant g 116.6 - 26.1. i. preliminary results |
this paper presents a new study of the spectral index distribution of the supernova remnant (snr) puppis a. the nature of field compact sources is also investigated according to the measured spectral indices. this work is based on new observations of puppis a and its surroundings performed with the australia telescope ... | radio spectral characteristics of the supernova remnant puppis a and nearby sources |
the expansion index and relative contact discontinuity positions of young type ia supernova remnants (snrs) evolving in a turbulent medium are investigated via implementing two-dimensional cylindrical magnetohydrodynamic simulations. in our simulations, two kinds of initial ejecta density profiles are considered: a pow... | evolutions of young type ia supernova remnants with two initial density profiles in a turbulent medium |
we employ 3d magnetohydrodynamic simulations to study the morphology and synchrotron emission of young supernova remnants evolving in a turbulent interstellar magnetic field, seeking to shed new light on to the polarization structure of the emission and on the debate concerning the quasi-parallel and quasi-perpendicula... | young bilateral supernova remnants evolving into a turbulent interstellar magnetic field |
the middle-aged supernova remnant ic 443 is interacting with molecular gas in its surroundings. $fermi$-lat has established that its gamma-ray emission at low energies shows the "pion bump" that is characteristic of hadronic emission. tev emission was previously established by magic and veritas at a site of interaction... | the tev morphology of the interacting supernova remnant ic 443 |
we present an interpretation of the time variability of the x-ray flux recently reported from a multiepoch campaign of 15 years of observations of the supernova remnant cassiopeia a by chandra. we show for the first time quantitatively that the [4.2-6] kev nonthermal flux increase up to 50% traces the growth of the mag... | vortical amplification of the magnetic field at an inward shock of supernova remnant cassiopeia a |
we present a study of the progenitor of the magnetar 1e 2259+586, from suzaku observations of the associated supernova remnant ctb 109. the suzaku spectra, either spatially integrated or spatially resolved, were successfully described by a two-component plasma model, which reconfirms a previous chandra result on the no... | study of the progenitor of the magnetar 1e 2259+586 through suzaku observations of the associated supernova remnant ctb 109 |
we sketch a scenario for the explosion of massive stars (supernovae) that differs from published scenarios of explosions as a two-step process, an initial gravitational core collapse followed by an expansion of matter after a bouncing on the core, which meet difficulties. our simple model, based on fluid mechanics and ... | implosion-explosion in supernovae |
multiband observations on the type ia supernova remnant sn 1006 indicate peculiar properties in its morphologies of emission in the radio, optical, and x-ray bands. in the hard x-rays, the remnant is bilateral with two opposite bright limbs with prominent protrusions. moreover, a filament has been detected at the radio... | numerically investigating the morphology of the supernova remnant sn 1006 in the ambient medium with a density discontinuity |
the shell type supernova remnant (snr) cas a exhibits structures at nearly all angular scales. previous studies show the angular power spectrum (cℓ) of the radio emission to be a broken power law, consistent with mhd turbulence. the break has been identified with the transition from 2d to 3d turbulence at the angular s... | the auto- and cross-angular power spectrum of the cas a supernova remnant in radio and x-ray |
the x-ray emission from a supernova remnant is a powerful diagnostic of the state of its shocked plasma. the temperature and the emission measure are related to the energy of the explosion, the age of the remnant, and the density of the surrounding medium. here we present the results of a study of the remnant populatio... | physical properties of the supernova remnant population in the small magellanic cloud |
g23.33-0.30 is a 600 m ⊙ infrared dark molecular filament that exhibits large nh3 velocity dispersions (σ ∼ 8 km s-1) and bright, narrow nh3(3, 3) line emission. we have probed g23.33-0.30 at the < 0.1 pc scale and confirmed that the narrow nh3(3, 3) line is emitted by four rare nh3(3, 3) masers, which are excited b... | the interaction between the supernova remnant w41 and the filamentary infrared dark cloud g23.33-0.30 |
we have carried out optical observations of the northeastern part of the supernova remnant ic 443 using the canada-france-hawaii telescope imaging spectrograph sitelle. the observations consist of three multispectral cubes covering an 11‧ × 11‧ area allowing the investigation of both the spatial and spectral variation ... | a multispectral analysis of the northeastern shell of ic 443 |
hi spectra of the supernova remnant g18.9-1.1 and the supernova remnant candidate g28.6+0.0 are analyzed. we compared the spectra to $^{13}$co emission spectra and to spectra of hii regions in the area to determine kinematic distances. g18.9-1.1 is at 2.1$\pm$0.4 kpc and g28.6+0.0 is at 9.0$\pm$0.3 kpc from the sun. us... | distance and evolutionary states of supernova remnant g18.9-1.1 and candidate g28.6+0.0 |
young galactic supernova remnants (snrs) are where we can observe closely the supernova (sn) ejecta and its interaction with circumstellar/interstellar medium. therefore, they provide an opportunity to explore the explosion and the final stage of the evolution of massive stars. near-infrared (nir) emission lines in snr... | near-infrared spectroscopy of young galactic supernova remnants |
a few particles of presolar al2o3 grains with sizes above 0.5 μm are believed to have been produced in the ejecta of core-collapse supernovae (sne). in order to clarify the formation condition of such large al2o3 grains, we investigate the condensation of al2o3 grains for wide ranges of the gas density and cooling rate... | probing the physical conditions of supernova ejecta with the measured sizes of presolar al2o3 grains |
the cygnus loop has been the focus of substantial debate concerning the contribution of charge exchange (cx) to supernova remnant (snr) x-ray emission. we take advantage of a distinct feature of cx, enhanced kα forbidden line emission, and employ the energy centroid of the o vii kα triplet as a diagnostic. based on x-r... | x-ray emission from charge exchange in the cygnus loop snr |
pulsars moving through interstellar medium (ism) produce bow shocks detected in hydrogen h α line emission. the morphology of the bow shock nebulae allows one to probe the properties of ism on scales ∼0.01 pc and smaller. we performed 2d relativistic magnetohydrodynamic modelling of the pulsar bow shock and simulated t... | fast-moving pulsars as probes of interstellar medium |
over the past decade, gamma-ray observations of supernova remnants with space-based instruments, such as astro-rivelatore gamma a immagini leggero (agile) and the fermi-large area telescope (lat), and ground-based instruments such as the high energy stereoscopic system (h.e.s.s.), the major atmospheric gamma-ray imagin... | high-energy gamma rays from supernova remnants |
the edges collaboration has reported the detection of a global 21-cm signal with a plateau centered at 76 mhz (i.e., redshift 17.2), with an amplitude of 500-500+200 mk. this anomalous measurement does not comport with standard cosmology, which can only accommodate an amplitude ≲230 mk. nevertheless, the line profile's... | the anomalous 21-cm absorption at high redshifts |
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