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we have simulated the expanded owens valley solar array (eovsa) radio images generated at multiple frequencies from a model solar active region, embedded in a realistic solar disk model, and explored the resulting data cube for different spectral analysis schemes to evaluate the potential for realizing one of eovsa’s m... | coronal magnetography of a simulated solar active region from microwave imaging spectropolarimetry |
millisecond pulsars (msps) are known as highly stable celestial clocks. nevertheless, recent studies have revealed the unstable nature of their integrated pulse profiles, which may limit the achievable pulsar timing precision. in this article, we present a case study on the pulse-profile variability of psr j1022+1001. ... | single-pulse and profile-variability study of psr j1022+1001 |
we search for indications of waves in the 25 - 2000 mhz radio spectrum of the 1 august 2010 event (sol2010-08-01t08:57:00l075c013), where fast propagating waves in the solar corona with periods of 181, 69, and 40 seconds were detected in uv observations. using the wavelet technique, we construct a new type of oscillati... | oscillation maps in the broadband radio spectrum of the 1 august 2010 event |
we have performed 3d isothermal mhd simulation of a magnetic rotating massive star with a non-zero dipole obliquity and predicted the radio/sub-mm observable light curves and continuum spectra for a frequency range compatible with alma. from these results we also compare the model input mass-loss to that calculated fro... | 3d mhd simulations and synthetic radio emission from an oblique rotating magnetic massive star |
radio emission in jets from young stellar objects (ysos) in the form of nonthermal emission has been seen toward several ysos. thought to be synchrotron emission from strong shocks in the jet, it could provide valuable information about the magnetic field in the jet. here we report on the detection of synchrotron emiss... | the first detection of a low-frequency turnover in nonthermal emission from the jet of a young star |
we observed the 43 ghz v = 1, 2, and 3 and 86 ghz v = 1 sio maser transitions quasi-simultaneously for a mira-variable-dominated sample of over 80 sources from the bulge asymmetries and dynamical evolution (baade) project, using atca, and statistically compared the relative line strengths. on average, the 43 ghz v = 1 ... | quasi-simultaneous 43 and 86 ghz sio maser observations and potential bias in the baade survey are resolved |
many of the details of how terrestrial gamma-ray flashes (tgfs) are produced, including their association with upward-propagating in-cloud lightning leader channels, remain poorly understood. measurements of the low-frequency radio emissions associated with tgf production continue to provide unique views and key insigh... | terrestrial gamma-ray flashes can be detected with radio measurements of energetic in-cloud pulses during thunderstorms |
well before the radio discovery of pulsars offered the first observational confirmation for their existence (hewish et al., nature 217:709-713, 1968), it had been suggested that neutron stars might be endowed with very strong magnetic fields of 1010-1014 g (hoyle et al., nature 203:914-916, 1964; pacini, nature 216:567... | strongly magnetized pulsars: explosive events and evolution |
the outer scutum-centaurus (osc) spiral arm is the most distant molecular spiral arm in the milky way, but until recently little was known about this structure. discovered by dame and thaddeus, the osc lies ∼15 kpc from the galactic center. due to the galactic warp, it rises to nearly 4° above the galactic plane in the... | high-mass star formation in the outer scutum-centaurus arm |
we study the spin-down changes of psr b1859+07 over a period of more than 28 years of radio observation. we identify that the time derivative of the rotational frequency (ν) varies quasi-periodically with a period of ∼350 d, switching mainly between two spin-down states. the profile shape of the pulsar is correlated wi... | correlated spin-down rates and radio emission in psr b1859+07 |
we assess the multiwavelength observable properties of the bow shock around a runaway early-type star using a combination of hydrodynamical modelling, radiative transfer calculations and synthetic imaging. instabilities associated with the forward shock produce dense knots of material which are warm, ionized and contai... | modelling multiwavelength observational characteristics of bow shocks from runaway early-type stars |
we present vrijhk photometry of the kh 15d t tauri binary system for the 2015/2016 and 2016/2017 observing seasons. for the first time in the modern (ccd) era, we are seeing star b fully emerge from behind the trailing edge of the precessing circumbinary ring during each apastron passage. we are, therefore, able to mea... | optical and radio observations of the t tauri binary kh 15d (v582 mon): stellar properties, disk mass limit, and discovery of a co outflow |
we study centimeter continuum emission of eight high- and intermediate-mass protostars that are part of the sofia massive star formation survey, thus building extended spectral energy distributions (seds) from the radio to the infrared. we discuss the morphology seen in the centimeter continuum images, which are mostly... | the soma radio survey. i. comprehensive seds of high-mass protostars from infrared to radio and the emergence of ionization feedback |
giant radio halos (rh) are diffuse, mpc-sized, synchrotron radio sources observed in a fraction of merging galaxy clusters. the current scenario for the origin of rhs assumes that turbulence generated during cluster mergers re-accelerates pre-existing fossil and/or secondary electrons in the intra-cluster-medium (icm) ... | cluster radio halos at the crossroads between astrophysics and cosmology in the ska era |
we have used the karl g. jansky very large array (vla) to carry out multi-epoch radio continuum monitoring of the orion nebula cluster (onc) and the background orion molecular cloud (omc; 3 epochs at q band and 11 epochs at ka band). our new observations reveal the presence of 19 radio sources, mainly concentrated in t... | short- and long-term radio variability of young stars in the orion nebula cluster and molecular cloud |
alma observations of co(1-0) and co(2-1) emissions of the circumstellar envelope of ep aqr, an oxygen-rich asymptotic giant branch star, are reported. a thorough analysis of their properties is presented using an original method based on the separation of the data cube into a low-velocity component associated with an e... | the morpho-kinematics of the circumstellar envelope around the agb star ep aqr |
radio emission has been detected in a broad variety of stellar objects from all stages of stellar evolution. however, most of our knowledge originates from targeted observations of small samples, which are strongly biased to sources which are peculiar at other wavelengths. in order to tackle this problem we have conduc... | scorpio: a deep survey of radio emission from the stellar life-cycle |
we conducted a survey of seven magnetic o-type stars and eleven b-type stars with masses above 8 m⊙ using the very large array in the 1, 3 and 13 cm bands. the survey resulted in a detection of two o- and two b-type stars. while the detected o-type stars - hd 37742 and hd 47129 - are in binary systems, the detected b-t... | a jvla survey of the high-frequency radio emission of the massive magnetic b- and o-type stars |
recently, a large number of hot magnetic stars have been discovered to produce auroral radio emission by the process of electron cyclotron maser emission (ecme). such stars have been given the name of main-sequence radio pulse emitters (mrps). the phenomenon characterizing mrps is very similar to that exhibited by plan... | what leads to premature upper cut-off frequencies of auroral radio emission from hot magnetic stars? |
during its polar orbits around jupiter, juno often crosses the boundaries of the jovian magnetosphere (namely the magnetopause and bow shock). from the boundary locations, the upstream solar wind dynamic pressure can be inferred, which in turn illustrates the state of compression or relaxation of the system. the aim of... | effect of a magnetospheric compression on jovian radio emissions: in situ case study using juno data |
imaging the low-frequency radio sun is an intrinsically challenging problem. meter-wavelength solar emission spans angular scales from a few arcminutes to a few degrees. these emissions show temporal and spectral variability on sub-second and sub-mhz scales. the brightness temperature of these emissions also varies by ... | working principle of the calibration algorithm for high dynamic range solar imaging with the square kilometre array precursor |
we present very large array observations toward the class 0 protostar l1157 mms at 6.8 and 9 mm with a resolution of ~0.″04 (14 au). we detect two sources within l1157 mms and interpret these sources as a binary protostar with a separation of ~16 au. the material directly surrounding the binary system within the inner ... | a 16 au binary in the class 0 protostar l1157 mms |
we use archival alma observations of the co(2-1) and sio(5-4) molecular line emissions of agb star r hya to illustrate the relative contributions of rotation, expansion and line broadening to the morphology and kinematics of the circumstellar envelope (cse) within some ~70 au (~0.″5) from the centre of the star. we giv... | contributions of rotation, expansion and line broadening to the morphology and kinematics of the inner cse of oxygen-rich agb star r hya |
zno/sic heterojunctions show great potential for various optoelectronic applications (e.g., ultraviolet light emitting diodes, photodetectors, and solar cells). however, the lack of a detailed understanding of the zno/sic interface prevents an efficient and rapid optimization of these devices. here, intrinsic (but inhe... | the isotype zno/sic heterojunction prepared by molecular beam epitaxy\u2009-\u2009a chemical inert interface with significant band discontinuities |
context. the zebra patterns observed in solar radio emission are very important for flare plasma diagnostics. the most promising model of these patterns is based on double plasma resonance instability, which generates upper-hybrid waves, which can be then transformed into the zebra emission.aims: we aim to study in det... | temperature dependent growth rates of the upper-hybrid waves and solar radio zebra patterns |
the spatial distribution features of electric field over three alpha transmitters in russia were analyzed based on the demeter satellite records at local nighttime during the solar minimum in december of 2008, where the three transmitters are with the same emitted power of 500 kw and the same radio waves at 11.9 khz, 1... | the spatial distribution features of three alpha transmitter signals at the topside ionosphere |
solar flares are complicated physical phenomena that are observable in a broad range of the electromagnetic spectrum, from radio waves to γ-rays. for a more comprehensive understanding of flares, it is necessary to perform a combined multi-wavelength analysis using observations from many satellites and ground-based obs... | an interactive multi-instrument database of solar flares |
aims: previous radio recombination line (rrl) observations of dust clumps identified in the apex telescope large area survey of the galaxy (atlasgal) have led to the detection of a large number of rrls in the 3 mm range. here, we aim to study their excitation with shorter wavelength (sub)millimeter radio recombination ... | new detections of (sub)millimeter hydrogen radio recombination lines towards high-mass star-forming clumps |
we report a simultaneous 44 and 95 ghz class i methanol maser survey toward 144 sources from the 95 ghz class i methanol maser catalog. the observations were made with the three telescopes of the korean very long baseline interferometry network operating in single-dish mode. the detection rates are 89% at 44 ghz and 77... | 44 ghz methanol masers: observations toward 95 ghz methanol masers |
h i stacking has proven to be a highly effective tool to statistically analyse average h i properties for samples of galaxies which may or may not be directly detected. with the plethora of h i data expected from the various upcoming h i surveys with the ska precursor and pathfinder telescopes, it will be helpful to st... | hiss, a new tool for h i stacking: application to nibles spectra |
we detail interferometric observations of 44 ghz class i methanol masers detected by malt-45 (a 7 mm unbiased auto-correlated spectral-line galactic-plane survey) using the australia telescope compact array. we detect 238 maser spots across 77 maser sites. using high-resolution positions, we compare the class i ch3oh m... | malt-45: a 7 mm survey of the southern galaxy - ii. atca follow-up observations of 44 ghz class i methanol masers |
two kinds of processes could occur during the flare decay phase: processes of energy release or processes of energy relaxation. quasi-periodic pulsations (qpps) of the broad-band emission are a good tool for the verification of mechanisms. we aim to study the processes during the decay phase of the x-class solar flare ... | quasi-periodic pulsations in a solar flare with an unusual phase shift |
we report on the third epoch of very long baseline interferometry (vlbi) observations of the radio-bright supernova sn 2011dh, located in the nearby (7.8 mpc) galaxy m51. the observations took place at t = 453 d after the explosion and at a frequency of 8.4 ghz. we obtained a fairly well-resolved image of the shell of ... | imaging the expanding shell of sn 2011dh |
we performed a radio recombination line (rrl) survey to construct a high-mass star-forming region (hmsfr) sample in the milky way based on the all-sky wide-field infrared survey explorer point-source catalog. the survey was observed with the shanghai 65 m tianma radio telescope covering 10 hydrogen rrl transitions rang... | a 4-6 ghz radio recombination line survey in the milky way |
the x-ray and euv emission of stars plays a key role in the loss and evolution of the atmospheres of their planets. the coronae of dwarf stars later than m6 appear to behave differently from those of earlier spectral types and are more x-ray dim and radio bright. too faint to have been observed by the extreme ultraviol... | pointing chandra toward the extreme ultraviolet fluxes of very low mass stars |
increases in the x-ray radiation that is emitted during a solar x-ray flare induce significant changes in the ionospheric d region. because of the numerous complex processes in the ionosphere and the characteristics of the radiation and plasma, the causal-consequential relationship between the x-ray radiation and ionos... | analysis of the relationship between the solar x-ray radiation intensity and the d-region electron density using satellite and ground-based radio data |
psr b0919+06 generally radiates radio pulses in a normal phase range. it is known for its occasional perplexing abnormal emission events wherein individual pulses come to an earlier phase range for a few tens of periods and then it returns to its usual phase. heretofore, only a few such events have been available for s... | jiamusi pulsar observations: i. abnormal emission events of psr b0919+06 |
aims: we present a new method for determining the magnetic field strength and plasma density in the solar zebra radio sources.methods: using the double plasma resonance (dpr) model of the zebra emission, we analytically derived the equations for computing the gyroharmonic number s of selected zebra lines and then solve... | determination of plasma parameters in solar zebra radio sources |
context. the binary system ar sco contains an m star and the only known radio-pulsing white dwarf. the system shows emission from radio to x-rays, likely dominated by synchrotron radiation. the mechanism that produces most of this emission remains unclear. two competing scenarios have been proposed: collimated outflows... | towards the origin of the radio emission in ar scorpii, the first radio-pulsing white dwarf binary |
the nearby star ɛ eridani has been a frequent target of radio surveys for stellar emission and extraterrestrial intelligence. using deep 2-4 ghz observations with the very large array, we have uncovered a 29 μjy compact, steady continuum radio source coincident with ɛ eridani to within 0"06 (≲2σ; 0.2 au at the distance... | detection of 2-4 ghz continuum emission from ɛ eridani |
we present multiepoch, large-scale (∼2000 arcmin2), fairly deep (∼16 μjy), high-resolution (∼1″) radio observations of the perseus star-forming complex obtained with the karl g. jansky very large array at frequencies of 4.5 and 7.5 ghz. these observations were mainly focused on the clouds ngc 1333 and ic 348, although ... | the gould’s belt very large array survey. v. the perseus region |
we report the discovery of variable radio emission associated with the t tauri star, v830 tau, which was recently shown to host a hot jupiter companion. very large array observations at a frequency of 6 ghz reveal a detection on 2011 may 1 with a flux density 919 ± 26 μjy, along with non-detections in two other epochs ... | variable radio emission from the young stellar host of a hot jupiter |
multiwavelength studies indicate that nuclear activity and bulge properties are closely related, but the details remain unclear. to study this further, we combine hubble space telescope bulge structural and photometric properties with 1.5 ghz, e-merlin nuclear radio continuum data from the lemmings survey for a large s... | lemmings. vi. connecting nuclear activity to bulge properties of active and inactive galaxies: radio scaling relations and galaxy environment |
despite their large impact on stellar and galactic evolution, the properties of outflows from red supergiants are not well characterized. we used the onsala 20m telescope to perform a spectral survey at 3 and 4 mm (68-116 ghz) of the red supergiant nml cyg, alongside the yellow hypergiant irc + 10420. our observations ... | multiple components in the molecular outflow of the red supergiant nml cyg |
we report mid-uv (muv) observations taken with hubble space telescope (hst)/wfc3, swift/uvot, and galex/nuv of the transitional millisecond pulsars xss j12270-4859 and psr j1023+0038 during their radio pulsar states. both systems were detected in our images and showed muv variability. at similar orbital phases, the muv... | mid-uv studies of the transitional millisecond pulsars xss j12270-4859 and psr j1023+0038 during their radio pulsar states |
the massive star-forming region w75n (b) is thought to host a cluster of massive protostars (vla 1, vla 2, and vla 3) undergoing different evolutionary stages. in this work, we present radio continuum data with the highest sensitivity and angular resolution obtained to date in this region, using the vla-a and covering ... | characterizing the radio continuum nature of sources in the massive star-forming region w75n (b) |
in this paper, the photoluminescence (pl) of hydrogenated amorphous silicon carbide (a-si1‑xcx:h) thin films obtained by plasma enhancement chemical vapor deposition (pecvd) is reported. strong pl is obtained after a fast annealing process for 60 s at temperatures of 200, 400, 600, and 800 °c. the thin films are charac... | enhanced photoluminescence of hydrogenated amorphous silicon carbide thin films by means of a fast thermal annealing process |
context. sharpless 269 (s 269) is one of a few hii regions in the outer spiral arm of the milky way with strong water maser emission. based on data from the very long baseline interferometry (vlbi) exploration of radio astrometry (vera) array, two parallax measurements have been published, which differ by nearly 2σ. ea... | resolving the distance controversy for sharpless 269. a possible kink in the outer arm |
recent galactic plane surveys of dust continuum emission at long wavelengths have identified a population of dense, massive clumps with no evidence for ongoing star formation. these massive starless clump candidates are excellent sites to search for the initial phases of massive star formation before the feedback from ... | searching for inflow toward massive starless clump candidates identified in the bolocam galactic plane survey |
despite the axisymmetry of saturn's internal field, saturn radio emissions like saturn kilometric radiation (skr) are modulated due to planetary rotation. with the completion of cassini mission in september 2017, we now have around 14 years of observation of saturn radio emissions, roughly from southern solstice to nor... | an sls5 longitude system based on the rotational modulation of saturn radio emissions |
ever-increasing multi-frequency imaging of solar observations suggests that solar flares often involve more than one magnetic fluxtube. some of the fluxtubes are closed, while others can contain open fields. the relative proportion of nonthermal electrons among those distinct loops is highly important for understanding... | a large-scale plume in an x-class solar flare |
context. some colliding-wind massive binaries, called particle-accelerating colliding-wind binaries (pacwb), exhibit synchrotron radio emission, which is assumed to be generated by a stellar magnetic field. however, no measurement of magnetic fields in these stars has ever been performed.aims: we aim at quantifying the... | search for magnetic fields in particle-accelerating colliding-wind binaries |
this paper presents a solely thermal flare, which we detected in the microwave range from the thermal gyro- and free-free emission it produced. an advantage of analyzing thermal gyro emission is its unique ability to precisely yield the magnetic field in the radiating volume. when combined with observationally deduced ... | energy partitions and evolution in a purely thermal solar flare |
we report on a simultaneous near-infrared, optical, and x-ray campaign performed in 2017 with the xmm-newton and swift satellites and the hawk-i instrument mounted on the very large telescope (vlt) on the transitional millisecond pulsar psr j1023+0038. near-infrared observations were performed in fast-photometric mode ... | peering at the outflow mechanisms in the transitional pulsar psr j1023+0038: simultaneous vlt, xmm-newton, and swift high-time resolution observations |
remote sensing with phased antenna arrays is based on measurement of the cross-correlations between the signals from each antenna pair. digital correlators have systematic errors due to the quantization losses. the correlation errors allow substantial abatement based on the assumption that the analog signals are stocha... | van vleck correction generalization for complex correlators with multilevel quantization |
high resolution alma observations of the recent (2.52 yr old) shell of nova v5668 sgr (2015) show a highly structured ionized gas distribution with small (1015 cm) clumps. these are the smallest structures ever observed in the remnant of a stellar thermonuclear explosion. no extended contiguous emission could be found ... | the structure of a recent nova shell as observed by alma |
defining the solar brightness temperature accurately at millimeter wavelengths has always been challenging. one of the main reasons has been the lack of a proper calibration source. new moon was used earlier as a calibration source. we carried out a new extensive set of observations at 8 mm using the new moon for calib... | measurements of the quiet-sun level brightness temperature at 8 mm |
radio‑frequency (rf) sputtering is a low‑cost technique for the deposition of large‑area single‑phase alinn on silicon layers with application in photovoltaic devices. here, the effect of the al mole fraction x from 0 to 0.56 on the structural, morphological, electrical, and optical properties of n‑alxin1−xn layers dep... | low‑to‑mid al content (x = 0–0.56) alxin1−xn layers deposited on si(100) by radio‑frequency sputtering |
electron density enhancement caused by electromagnetic radiation emitted during a solar x-ray flare has the potential to increase high frequency (hf; 3-30 mhz) absorption in the dayside d-region ionosphere, impacting shortwave radio signals by reducing the signal strength, a phenomenon commonly referred to as shortwave... | data-based optimization of a simple shortwave fadeout absorption model |
we report on the variation of electric power density linked to very low frequency (vlf) signal observed during the minimum of solar cycle 25. the detected vlf signal is emitted by the nwc radio station localized in the southern hemisphere, at 21.5° s and 114.2° e. we attempt in this work to quantify the beam as detecte... | case study of radio emission beam associated to very low frequency signal recorded onboard cses satellite |
cadmium sulfide (cds) thin films are deposited on the fluorine doped tin oxide coated glass substrate using the radio frequency magnetron sputtering setup. the effects of annealing in air on the structural, morphological, and optical properties of cds thin film are studied. optimal annealing temperature is investigated... | investigation of annealing temperature effect on magnetron sputtered cadmium sulfide thin film properties |
radio emission from interplanetary shocks, planetary foreshocks, and some solar flares occurs in the so-called "plasma emission" framework. the generally accepted scenario begins with electrostatic langmuir waves that are driven by a suprathermal electron beam on the landau resonance. these langmuir waves then mode-con... | langmuir-slow extraordinary mode magnetic signature observations with parker solar probe |
sgr e is a massive star formation complex found toward the galactic center that consists of numerous discrete, compact h ii regions. it is located at the intersection between the central molecular zone (cmz) and the far dust lane of the galactic bar, similar to "hot spots" seen in external galaxies. compared with other... | unusual galactic h ii regions at the intersection of the central molecular zone and the far dust lane |
the galactic plane has been mapped from l = 34.°75 to 45.°25 and b = -5.°25 to 5.°25 in the co (j = 1-0) emission with the 13.7 m telescope of the purple mountain observatory. the unbiased survey covers a large area of 110 square degrees sampled every 30″ with a velocity resolution of ∼ 0.2 {km} {{{s}}}-1. in this pape... | the distant outer gas arm between l=35 and l=45 |
context. the double plasma resonance (dpr) instability plays a basic role in the generation of solar radio zebras. in the plasma, consisting of the loss-cone type distribution of hot electrons and much denser and colder background plasma, this instability generates the upper-hybrid waves, which are then transformed int... | double plasma resonance instability as a source of solar zebra emission |
we investigate the predicted circumstellar properties of type ia supernova progenitor systems with non-degenerate helium star donors. it has been suggested that systems consisting of a carbon + oxygen white dwarf and a helium star can lead to type ia supernova explosions. binary evolution calculations for the helium st... | circumstellar properties of type ia supernovae from the helium star donor channel |
we use ultradeep 20 cm data from the karl g. jansky very large array and 850 μm data from scuba-2 and the submillimeter array of an 124 arcmin2 region of the chandra deep field-north to analyze the high radio power ({p}20{cm}> {10}31 erg s-1 hz-1) population. we find that 20 (42 ± 9%) of the spectroscopically identi... | a submillimeter perspective on the goods fields. ii. the high radio power population in the goods-n |
context. the circumstellar ammonia (nh3) chemistry in evolved stars is poorly understood. previous observations and modelling showed that nh3 abundance in oxygen-rich stars is several orders of magnitude above that predicted by equilibrium chemistry.aims: we would like to characterise the spatial distribution and excit... | circumstellar ammonia in oxygen-rich evolved stars |
giant pulses (gps) are extremely bright individual pulses of radio pulsar. in microbursts of crab pulsar, which is an active gp emitter, zebra-pattern-like spectral structures are observed, which are reminiscent of the "zebra bands" that are observed in type iv solar radio flares. however, band spacing linearly increas... | pulsar giant pulse: coherent instability near light cylinder |
in this paper, we use high-quality rest-uv spectra of three radio galaxies at z ~ 3 observed with the fors2 camera on the very large telescope to measure the flux of several emission lines, including relatively faint ones, such as n iv]λ1486, o iii]λ1663, and [ne iv]λ2424. additionally, we collect fluxes of faint rest-... | multiline assessment of narrow-line regions in z 3 radio galaxies |
we identify a set of ~100 "cold" solar flares and perform a statistical analysis of them in the microwave range. cold flares are characterized by a weak thermal response relative to nonthermal emission. this work is a follow-up of a previous statistical study of cold flares, which focused on hard x-ray emission to quan... | cold solar flares. i. microwave domain |
massive stars moving at supersonic peculiar velocities through the interstellar medium (ism) can create bow shocks, arc-like structures at the interface between the stellar wind and the ism. many such bow shocks have been detected and catalogued at ir wavelengths, but detections in other wavebands remain rare. striking... | radio detections of ir-selected runaway stellar bow shocks |
to understand the mass distribution and co-evolution of supermassive black holes with their host galaxy, it is crucial to measure the black hole mass of agn. reverberation mapping is a unique tool to estimate the black hole masses in agn. we performed spectroscopic reverberation study using long-term monitoring data wi... | spectroscopic reverberation mapping of quasar pks 0736 + 017: broad-line region and black-hole mass |
the modulation of the microwave emission intensity from a flaring loop by a standing linear sausage fast magnetoacoustic wave is considered in terms of a straight plasma slab with the perpendicular epstein profile of the plasma density, penetrated by a magnetic field. the emission is of the gyrosynchrotron (gs) nature,... | modulation of the solar microwave emission by sausage oscillations |
solar flares, resulting from magnetic activity of the sun, are among the most energetic events in the solar system and in extreme cases directly affect our highly technological society. in this work, we analyze a solar flare detected at millimeter and centimeter wavelengths, as well as x-rays above 1 mev. observations ... | broken power-law energy spectra of the accelerated electrons detected in radio and hard x-rays during the sol2013-05-13 event |
context. the long-period, highly eccentric o-star binary 9 sgr, known for its non-thermal radio emission and its relatively bright x-ray emission, went through its periastron in 2013.aims: such an event can be used to observationally test the predictions of the theory of colliding stellar winds over a broad range of wa... | testing the theory of colliding winds: the periastron passage of 9 sagittarii. i. x-ray and optical spectroscopy |
a new radio component namely saturn anomalous myriametric radiation (sam) is reported. a total of 193 sam events have been identified by using all the cassini saturn orbital data. sam emissions are l-o mode radio emission and occasionally accompanied by a first harmonic in r-x mode. sam's intensities decrease with incr... | saturn anomalous myriametric radiation, a new type of saturn radio emission revealed by cassini |
massive, early-type stars have been detected as radio sources for many decades. their thermal winds radiate free-free continuum and in binary systems hosting a colliding-wind region, non-thermal emission has also been detected. to date, the most abundant data have been collected from frequencies higher than 1 ghz. we p... | megahertz emission of massive early-type stars in the cygnus region |
the magnetization of solar and extrasolar gas giants is critically dependent on the electronic and mass transport coefficients of their convective fluid interiors. we analyze recent laboratory experimental results on metallic hydrogen to derive a new conductivity profile for the jovian-like planets. we combine this rev... | size and strength of self-excited dynamos in jupiter-like extrasolar planets |
aims: we performed a multi-wavelength study toward the filamentary cloud g47.06+0.26 to investigate the gas kinematics and star formation.methods: we present the 12co (j = 1-0), 13co (j = 1-0) and c18o (j = 1-0) observations of g47.06+0.26 obtained with the purple mountain observation (pmo) 13.7 m radio telescope to in... | gas kinematics and star formation in the filamentary molecular cloud g47.06+0.26 |
the most energetic flares start with a filament rise followed by magnetic reconnection below this filament. the start of the reconnection corresponds to the beginning of the flare impulsive phase. in this paper we study processes before this phase. during the filament rise we recognize an unusual radio continuum with a... | radio, euv, and x-ray observations during a filament rise in the 2011 june 7 solar flare |
we present a detailed study of a high-redshift iron low-ionization broad absorption line (felobal) quasar (sdss1214 at z = 1.046), including new interferometric 12co j = 2-1 observations, optical through far-infrared photometry, and mid-infrared spectroscopy. the co line is well fit by a single gaussian centred 40 km s... | the mid-infrared and co gas properties of an extreme star-forming felobal quasar |
the radio emission of pulsar b1451-68 contains two polarization modes of similar strength, which produce two clear orthogonal polarization angle tracks. when viewed on a poincaré sphere, the emission is composed of two flux patches that rotate meridionally as a function of pulse longitude and pass through the stokes v ... | circular polarization in radio pulsar psr b1451-68: coherent mode transitions and intrabeam interference |
context. recent theoretical and observational studies debate the similarities of the formation process of high- (>8 m⊙) and low-mass stars. the formation of low-mass stars is directly associated with the presence of disks and jets. theoretical models predict that stars with masses up to 140 m⊙ can be formed through ... | search for radio jets from massive young stellar objects. association of radio jets with h2o and ch3oh masers |
we present results revealing microwave pulsations produced in a model of a flaring twisted solar coronal loop, without any external oscillatory driver. two types of oscillations are identified: slowly decaying oscillations with a period of about 70-75 s and amplitude of about 5-10 per cent seen in loops both with and w... | pulsations of microwave emission from a solar flare in a twisted loop caused by intrinsic magnetohydrodynamic oscillations |
we present high-angular-resolution radio continuum observations of the quintuplet cluster, one of the most emblematic massive clusters in the galactic centre. data were acquired in two epochs and at 6 and 10 ghz with the karl g. jansky very large array. with this work we have quadrupled the number of known radio stars ... | radio observations of massive stars in the galactic centre: the quintuplet cluster |
magnetic reconnection can convert magnetic energy into kinetic energy of non-thermal electron beams. those accelerated electrons can, in turn, cause radio emission in astrophysical plasma environments, such as solar flares via micro-instabilities. the properties of the electron velocity distribution functions (evdfs) o... | non-thermal electron velocity distribution functions due to 3d kinetic magnetic reconnection for solar coronal plasma conditions |
we report on interferometric observations of a face-on accretion system around the high-mass young stellar object, g353.273+0.641. the innermost accretion system of 100 au radius was resolved in a 45 ghz continuum image taken with the jansky-very large array. our spectral energy distribution analysis indicated that the... | a face-on accretion system in high-mass star formation: possible dusty infall streams within 100 au |
remote volcanic aerosol optical depth (aod) observations of mount etna summit and distal bulk plume have been carried out between 14 and 20 july 2016 in the framework of the epl-radio project. ultraviolet (uv) and near-infrared (nir) aods were measured using a microtops-ii ozone monitor (miiom) sun photometer, using a ... | a novel methodology to determine volcanic aerosols optical properties in the uv and nir and ångström parameters using sun photometry |
aims: the zebra structures observed in radio waves during solar flares are some of the most important structures used as diagnostics of solar flare plasmas. we here not only analyze the so-called double plasma-resonance (dpr) surfaces, but also estimate the effects of their form on the size of the zebra sources and bri... | double plasma-resonance surfaces in flare loops and radio zebra emission |
ngc 3115 is the nearest galaxy hosting a billion solar mass black hole and is also a low-luminosity active galactic nucleus (llagn). x-ray observations of this llagn are able to spatially resolve the hot gas within the sphere of gravitational influence of the supermassive black hole. these observations make ngc 3115 an... | the multiwavelength spectrum of ngc 3115: hot accretion flow properties |
we document the variability in atomic oxygen inferred by the sounding of the atmosphere with broadband emission radiometry (saber) instrument on the nasa/timed satellite in the lower mesosphere (50-80 km altitude) according to its diurnal, latitudinal, seasonal and solar cycle components. the dominant variation is diur... | implications of odd oxygen observations by the timed/saber instrument for lower d region ionospheric modeling |
aims: we aim to expand our understanding of radio wave emission and propagation in the pulsar magnetosphere by studying the polarisation of drifting sub-pulses in highly sensitive observations of psr b1919+21 recorded at the arecibo observatory.methods: we apply and compare several methods of analysis and visualisation... | the polarisation of the drifting sub-pulses from psr b1919+21 |
we study the nonthermal emission from the interaction between magnetized jupiter-like exoplanets and the wind from their host star. the supersonic motion of planets through the wind forms a bow shock that accelerates electrons that produce nonthermal radiation across a broad wavelength range. we discuss three wind mass... | nonthermal emission from the interaction of magnetized exoplanets with the wind of their host star |
context. a discrepancy exists between the abundance of ammonia (nh3) derived previously for the circumstellar envelope (cse) of irc+10216 from far-ir submillimeter rotational lines and that inferred from radio inversion or mid-infrared (mir) absorption transitions.aims: to address the discrepancy described above, new h... | herschel/hifi observations of the circumstellar ammonia lines in irc+10216 |
the circumstellar environments of objects on the asymptotic giant branch and beyond are rich in molecular species. nevertheless, methanol has never been detected in such an object, and is therefore often taken as a clear signpost for a young stellar object. however, we report the first detection of ch3oh in a post-agb ... | first detection of methanol towards a post-agb object, hd 101584 |
this work presents a systematic investigation of the influence of weather conditions on the calibration errors by using gaussian fitness, least chi-square linear fitness, and wavelet transform to analyze the calibration coefficients from observations of the chinese solar broadband radio spectrometers (at frequency band... | study of calibration of solar radio spectrometers and the quiet-sun radio emission |
the paper is concerned with the study of the star-forming regions s231-s235 in radio lines of molecules of the interstellar medium—carbon monoxide (co), ammonia (nh3), cyanoacetylene (hc3n), in maser lines—methanol (ch3oh) and water vapor (h2o). the regions s231-s235 belong to the giant molecular cloudg174+2.5. the goa... | molecular emission in dense massive clumps from the star-forming regions s231-s235 |
the co(1-0) and (2-1) emission of the circumstellar envelope of the asymptotic giant branch (agb) star ep aqr has been observed in 2003 using the iram plateau-de-bure interferometer and in 2004 with the iram 30-m telescope at pico veleta. the line profiles reveal the presence of two distinct components centred on the s... | 12co emission from ep aquarii: another example of an axi-symmetric agb wind? |
we present further development of a pulsar emission model based on multiple streams diverging away from the magnetic dipole axis, and forming azimuthally structured fan-shaped beams. it is shown that this geometry, successfully tested on profiles with bifurcated features, naturally solves several classical pulsar probl... | the origin of the frequency-dependent behaviour of pulsar radio profiles |
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