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we define deriving semantic class targets as a novel multi-modal task. by doing so, we aim to improve classification schemes in the physical sciences which can be severely abstracted and obfuscating. we address this task for upcoming radio astronomy surveys and present the derived semantic radio galaxy morphology class... | a new task: deriving semantic class targets for the physical sciences |
while unobscured and radio-quiet active galactic nuclei are regularly being found at redshifts$z > 6$, their obscured and radio-loud counterparts remain elusive. we build upon our successful pilot study, presenting a new sample of low-frequency-selected candidate high-redshift radio galaxies (hzrgs) over a sky area ... | the gleaming of the first supermassive black holes: ii. a new sample of high-redshift radio galaxy candidates |
the arianna detector is designed to detect neutrinos with energies above 1017 ev. due to the similarities in generated radio signals, cosmic rays are often used as test beams for neutrino detectors. some arianna detector stations are equipped with antennas capable of detecting air showers. since the radio emission prop... | measuring the polarization reconstruction resolution of the arianna neutrino detector with cosmic rays |
transient radio frequency interference (rfi) is detrimental to radio astronomy. it is typically broadband, intermittent and particularly difficult to classify by source. rfi of this type can be generated by devices like mechanical relays, fluorescent lights or ac machines. such sources may be present in the vicinity of... | a cnn and lstm-based approach to classifying transient radio frequency interference |
the square kilometer array (ska) is a planned radio interferometer of unprecedented scale that will revolutionize low-frequency radio astronomy when completed. in particular, one of its core science drivers is the systematic mapping of the cosmic dawn and epoch of reionization, which mark the birth of the first stars a... | ska-low intensity mapping pathfinder updates: deeper 21 cm power spectrum limits from improved analysis frameworks |
we conduct 24.4 fps optical observations of repeating fast radio burst (frb) 20190520b using tomo-e gozen, a high-speed cmos camera mounted on the kiso 105 cm schmidt telescope, simultaneously with radio observations carried out using the five-hundred-meter aperture spherical radio telescope (fast). we succeeded in the... | deep simultaneous limits on optical emission from frb 20190520b by 24.4 fps observations with tomo-e gozen |
we have mapped $\mathrm{hcn}$ and hco+ (j = 1 → 0) line emission toward a sample of seven star-forming regions (with $12+\mathrm{log}[{\rm{o}}/{\rm{h}}]$ ranging from 8.34 to 8.69) in the outer milky way (galactocentric distance >9.5 kpc), using the 14 m radio telescope of the taeduk radio astronomy observatory. we ... | tracers of dense gas in the outer galaxy |
while protoplanetary disks are often treated as isolated systems in planet formation models, observations increasingly suggest that vigorous interactions between class ii disks and their environments are not rare. do tau is a t tauri star that has previously been hypothesized to have undergone a close encounter with th... | disk evolution study through imaging of nearby young stars (destinys): a panchromatic view of do tau's complex kilo-astronomical-unit environment |
in the radio occultation (ro) experiments, the difference between observed and predicted doppler, called frequency residuals, form basic input data to retrieve the vertical profiles of atmospheric parameters. in this paper, we compare different methods to estimate frequency residuals in a one-way downlink single freque... | on the estimation of frequency residuals in a radio occultation experiment |
we explore the possibility of multi-parametric resonances from time varying sound speed during cosmological inflation. in particular, we fix our set-up to the simpler case beyond a single oscillation model already explored in literature: two sinusoidal harmonics around a constant sound speed equal to one. we find that,... | induced gravitational waves from multi-sound speed resonances during cosmological inflation |
we present a study of the correlation between 22 ghz water maser emission and far-infrared/submillimeter (ir/sub-mm) sources. the generalized linear model (glm) is used to predict h2o maser detection in a particular source with defined physical parameters. we checked the glm predictions by observing a sample of selecte... | water masers as an early tracer of star formation |
radio bursts are sensitive tracers of non-thermal electron populations in the solar corona. they are produced by electron beams and shock waves propagating through the corona and the heliosphere, and by trapped electron populations in coronal mass ejections (cmes) and in quiescent active regions. combining space-borne ... | orfees - a radio spectrograph for the study of solar radio bursts and space weather applications |
flagging of radio frequency interference (rfi) in time-frequency visibility data is an increasingly important challenge in radio astronomy. we present r-net, a deep convolutional resnet architecture that significantly outperforms existing algorithms - including the default meerkat rfi flagger, and deep u-net architectu... | deep learning improves identification of radio frequency interference |
a significant discrepancy of up to 0.6 myr exists between radio-isotopically calibrated and astronomically tuned time scales of the late eocene-oligocene. we explore the possible causes of this discrepancy through the acquisition of "high-precision" 206pb/238u dating of zircons from 11 volcanic ash beds from the umbria... | reducing disparity in radio-isotopic and astrochronology-based time scales of the late eocene and oligocene |
rotating radio transients (rrats) are peculiar astronomical objects whose emission mechanism remains under investigation. in this paper, we present observations of three rrats, j1538+2345, j1854+0306 and j1913+1330, carried out with the five-hundred-meter aperture spherical radio telescope (fast). specifically, we anal... | study of three rotating radio transients with fast |
we investigate the performance of machine-learning techniques in classifying active galactic nuclei (agns), including x-ray-selected agns (xagns), infrared-selected agns (iragns), and radio-selected agns (ragns). using the known physical parameters in the cosmic evolution survey (cosmos) field, we are able to create qu... | identifying agn host galaxies by machine learning with hsc+wise |
we performed deep observations to search for radio pulsations in the directions of 375 unassociated fermi large area telescope γ-ray sources using the giant metrewave radio telescope (gmrt) at 322 and 607 mhz. in this paper we report the discovery of three millisecond pulsars (msps), psr j0248+4230, psr j1207-5050, and... | discovery and timing of three millisecond pulsars in radio and gamma-rays with the giant metrewave radio telescope and fermi large area telescope |
we report results of the performance evaluation of a new hardware correlator in korea, the daejeon correlator, developed by the korea astronomy and space science institute (kasi) and the national astronomical observatory of japan (naoj). we conducted very long baseline interferometry (vlbi) observations at 22~ghz with ... | a new hardware correlator in korea: performance evaluation using kvn observations |
in the era of radio astronomy, the high sensitivity of the square kilometre array (ska) could play a decisive role in the detection of new radio sources. in this work, we study the ska sensitivity to the synchrotron radio emission expected by the annihilation of tev dm candidate in the draco dwarf spheroidal galaxy. on... | ska-phase 1 sensitivity to synchrotron radio emission from multi-tev dark matter candidates |
the galactic interstellar medium hosts a significant magnetic field, which can be probed through the synchrotron emission produced from its interaction with relativistic electrons. linearly polarized synchrotron emission is generated throughout the galaxy and, at longer wavelengths, modified along nearly every path by ... | the global magneto-ionic medium survey: a faraday depth survey of the northern sky covering 1280-1750 mhz |
revealing the cosmic reionization history is at the frontier of extragalactic astronomy. the power spectrum of the cosmic microwave background (cmb) polarization can be used to constrain the reionization history. here, we propose a cmb-independent method using fast radio bursts (frbs) to directly measure the ionization... | revealing the cosmic reionization history with fast radio bursts in the era of square kilometre array |
with the advent of powerful telescopes such as the square kilometer array and the vera c. rubin observatory, we are entering an era of multiwavelength transient astronomy that will lead to a dramatic increase in data volume. machine learning techniques are well suited to address this data challenge and rapidly classify... | classification of multiwavelength transients with machine learning |
the icecube neutrino observatory opened the window on neutrino astronomy by discovering high-energy astrophysical neutrinos in 2013 and identifying the first compelling astrophysical neutrino source, the blazar txs0506 + 056, in 2017. in this proceeding, we will discuss the science reach and ongoing development of the ... | the icecube-gen2 neutrino observatory |
we present muse at vlt imaging spectroscopy of rest-frame ultraviolet emission lines and alma observations of the [c i] 3p1-3p0 emission line, probing both the ionized and diffuse molecular medium around the radio galaxy 4c 19.71 at z ≃ 3.6. this radio galaxy has extended lyα emission over a region ∼100 kpc in size pre... | alma and muse observations reveal a quiescent multi-phase circumgalactic medium around the z ≃ 3.6 radio galaxy 4c 19.71 |
the radiative cooling rate of cationic 1-cyanonaphthalene is determined from storage ring experiments and shown to be consistent with recurrent fluorescence. the rapid cooling helps explain the abundance of the neutral molecule in molecular clouds. several small polycyclic aromatic hydrocarbons (pahs) have been identif... | experimental radiative cooling rates of a polycyclic aromatic hydrocarbon cation |
we investigate hadronic and leptonic scenarios for the gev-tev gamma-ray emission from jets of the microquasar ss 433. the emission region of the tev photons coincides with the x-ray knots, where electrons are efficiently accelerated. on the other hand, the optical high-density filaments are also located close to the x... | deciphering the origin of the gev-tev gamma-ray emission from ss 433 |
the radioastron ground-space interferometer provides the highest angular resolution achieved now in astronomy. the detection of interferometric fringes from quasars with this angular resolution on baselines of 100-200 thousand km suggests the brightness temperatures which exceed the compton limit by two orders of magni... | radioastron science program five years after launch: main science results |
time domain radio astronomy observing campaigns frequently generate large volumes of data. our goal is to develop automated methods that can identify events of interest buried within the larger data stream. the v-fastr fast transient system was designed to detect rare fast radio bursts within data collected by the very... | a machine learning classifier for fast radio burst detection at the vlba |
in 2017 the event horizon telescope (eht) observed the supermassive black hole at the center of the milky way, sagittarius a* (sgr a*), at a frequency of 228.1 ghz (λ = 1.3 mm). the fundamental physics tests that even a single pulsar orbiting sgr a* would enable motivate searching for pulsars in eht data sets. the high... | a search for pulsars around sgr a* in the first event horizon telescope data set |
context. peta-ev (pev) astronomy emerged in 2021 with the discovery of ultra-high-energy gamma-ray sources associated with powerful natural particle accelerators known as pevatrons. in order to determine the nature of their emission, namely whether it has a hadronic or leptonic origin, it is essential to characterise t... | evidence for a gamma-ray molecular target in the enigmatic pevatron candidate lhaaso j2108+5157 |
the development of new phased array systems in radio astronomy, as the low frequency array (lofar) and the square kilometre array (ska), formed of a large number of small and flexible elementary antennas, has led to significant challenges. among them, model calibration is a crucial step in order to provide accurate and... | robust calibration of radio interferometers in non-gaussian environment |
atmospheric water vapor is the main limiting factor of atmospheric transparency in the mm and submm wavelength spectral windows. thus, dry sites are needed for the installation and successful operation of radio astronomy observatories exploiting those spectral windows. temperature and wind are variables of special cons... | precipitable water vapor, temperature, and wind statistics at sites suitable for mm and submm wavelength astronomy in northern chile |
3c 84 (ngc 1275) is the bright radio core of the perseus cluster. even in the absence of strong relativistic effects, the source has been detected at γ-rays up to tev energies. despite its intensive study, the physical processes responsible for the high-energy emission in the source remain unanswered. we present a deta... | a detailed kinematic study of 3c 84 and its connection to γ-rays |
we draw a multimessenger picture of j1048+7143, a flat-spectrum radio quasar known to show quasiperiodic oscillations in the γ-ray regime. we generate the adaptively binned fermi large area telescope light curve of this source above 168 mev to find three major γ-ray flares of the source, such that each of the three fla... | multimessenger picture of j1048+7143 |
we present optical, near-infrared, and radio observations of supernova (sn) sn iib 2022crv. we show that it retained a very thin h envelope and transitioned from an sn iib to an sn ib; prominent hα seen in the pre-maximum phase diminishes toward the post-maximum phase, while he i lines show increasing strength. synapps... | bridging between type iib and ib supernovae: sn iib 2022crv with a very thin hydrogen envelope |
context. intended and unintended radio emissions from satellites can interfere with sensitive radio telescopes in the frequency ranges of key experiments in astrophysics and cosmology. we detect strong intended and unintended electromagnetic radiation from starlink satellites at the site of the future ska-low facility ... | detection of intended and unintended emissions from starlink satellites in the ska-low frequency range, at the ska-low site, with an ska-low station analogue |
we present extensive multifrequency karl g. jansky very large array (vla) and very long baseline array (vlba) observations of the radio-bright supernova (sn) iib sn 2004c that span ~40-2793 days post-explosion. we interpret the temporal evolution of the radio spectral energy distribution in the context of synchrotron s... | radio analysis of sn2004c reveals an unusual csm density profile as a harbinger of core collapse |
magnetars are young neutron stars powered by the strongest magnetic fields in the universe (1013-15 g). their transient x-ray emission usually manifests as short (a few hundred milliseconds), bright, energetic (~1040-41 erg) x-ray bursts. since its discovery in 2014, sgr j1935+2154 has become one of the most prolific m... | quasiperiodic peak energy oscillations in x-ray bursts from sgr j1935+2154 |
the search for astronomical pulsed signals within noisy data in the radio band is usually performed through an initial fourier analysis to find "candidate" frequencies and then refined through the folding of the time series using trial frequencies close to the candidate. in order to establish the significance of the pu... | extending the z2n and h statistics to generic pulsed profiles |
we present a novel ai approach for high-resolution high-dynamic range synthesis imaging by radio interferometry (ri) in astronomy. r2d2, standing for ``{r}esidual-to-{r}esidual {d}nn series for high-{d}ynamic range imaging'', is a model-based data-driven approach relying on hybrid deep neural networks (dnns) and data-c... | ultra-fast high-dynamic range imaging of cygnus a with the r2d2 deep neural network series |
the vertical distribution of trace gases in planetary atmospheres can be obtained with observations of the atmosphere's thermal emission. inverting radio observations to recover the atmospheric structure, however, is nontrivial, and the solutions are degenerate. we propose a modeling framework to prescribe a vertical d... | ammonia abundance derived from juno mwr and vla observations of jupiter |
the hitachi and takahagi 32 m radio telescopes (former satellite communication antennas) were so upgraded as to work at 6, 8, and 22 ghz. we developed the receiver systems, if systems, back-end systems (including samplers and recorders), and reference systems. we measured the performance of the antennas. the system tem... | the hitachi and takahagi 32 m radio telescopes: upgrade of the antennas from satellite communication to radio astronomy |
the third iteration of the international celestial reference frame (icrf3) is made up of 4536 quasars observed at s/x bands using very-long-baseline interferometry. these sources are high-redshift quasars, typically between 1 < z < 2, that are believed to host active galactic nuclei at their centers. the position... | imaging sources in the third realization of the international celestial reference frame |
after decades of fast-paced technical advances, optical/infrared (o/ir) interferometry has seen a revolution in recent years: <label>■</label>the gravity instrument at the very large telescope interferometer (vlti) with four 8-m telescopes reaches thousand-times-fainter objects than possible with earlier in... | advances in optical/infrared interferometry |
we report the results of atacama large millimeter/submillimeter array (alma) 1-2 kpc resolution, three rotational transition-line (j = 2-1, j = 3-2, and j = 4-3) observations of multiple dense molecular gas tracers (hcn, hco+, and hnc) for 10 nearby (ultra)luminous infrared galaxies ((u)lirgs). following the matching o... | dense molecular gas properties of the central kiloparsec of nearby ultraluminous infrared galaxies constrained by alma three transition-line observations |
in order to characterize and model the beam-weighted foreground for global 21 cm signal experiments, we present a methodology for generating basis eigenvectors that combines analytical and observational models of both the galactic spectral index and sky brightness temperature with simulations of beams having various an... | modeling the galactic foreground and beam chromaticity for global 21 cm cosmology |
we present arecibo 327 mhz confirmation and follow-up studies of seven new pulsars discovered by the five-hundred-meter aperture spherical radio telescope (fast). these pulsars are discovered in a pilot program of the commensal radio astronomy fast survey (crafts) with the ultra-wide-bandwidth commissioning receiver. f... | an arecibo follow-up study of seven pulsars discovered by five-hundred-meter aperture spherical radio telescope (fast) |
the murchison widefield array is a low-frequency square kilometre array precursor located at the murchison radio-astronomy observatory in western australia. primarily designed as an imaging telescope, but with a flexible signal path, the capabilities of this telescope have recently been extended to include off-line inc... | mwa tied-array processing i: calibration and beamformation |
context. low-frequency radio arrays are opening a new window for the study of the sky, both to study new phenomena and to better characterize known source classes. being flat-spectrum sources, blazars are so far poorly studied at low radio frequencies.aims: we characterize the spectral properties of the blazar populati... | high-energy sources at low radio frequency: the murchison widefield array view of fermi blazars |
aims: from the early days in γ-ray astronomy, locating the origin of gev emission within the core of an active galactic nucleus (agn) persisted as an open question; the problem is to discern between near- and far-site scenarios with respect to the distance from the super massive central engine. we investigate this ques... | the γ-ray emitting region in low synchrotron peak blazars. testing self-synchrotron compton and external compton scenarios |
the maximum entropy method (mem) is a well known deconvolution technique in radio-interferometry. this method solves a non-linear optimization problem with an entropy regularization term. other heuristics such as clean are faster but highly user dependent. nevertheless, mem has the following advantages: it is unsupervi... | multi-gpu maximum entropy image synthesis for radio astronomy |
we perform a virial analysis of starless dense cores in three nearby star-forming regions: l1688 in ophiuchus, ngc 1333 in perseus, and b18 in taurus. our analysis takes advantage of comprehensive kinematic information for the dense gas in all of these regions made publicly available through the green bank ammonia surv... | the green bank ammonia survey: a virial analysis of gould belt clouds in data release 1 |
context. the venerable nod2 data reduction software package for single-dish radio continuum observations, which was developed for use at the 100-m effelsberg radio telescope, has been successfully applied over many decades. modern computing facilities, however, call for a new design.aims: we aim to develop an interacti... | the nod3 software package: a graphical user interface-supported reduction package for single-dish radio continuum and polarisation observations |
in 2016 september, the microquasar cygnus x-3 underwent a giant radio flare, which was monitored for 6 d with the medicina radio astronomical station and the sardinia radio telescope. long observations were performed in order to follow the evolution of the flare on an hourly scale, covering six frequency ranges from 1.... | single-dish and vlbi observations of cygnus x-3 during the 2016 giant flare episode |
to study the early phases of massive star formation, we present alma observations of sio(5-4) emission and vla observations of 6 cm continuum emission toward 32 infrared dark cloud clumps, spatially resolved down to ≲0.05 pc. out of the 32 clumps, we detect sio emission in 20 clumps, and in 11 of them the sio emission ... | sio outflows as tracers of massive star formation in infrared dark clouds |
the detection of gravitational waves from a neutron star merger, gw170817, marked the dawn of a new era in time-domain astronomy. monitoring of the radio emission produced by the merger, including high-resolution radio imaging, enabled measurements of merger properties including the energetics and inclination angle. in... | radio afterglows from compact binary coalescences: prospects for next-generation telescopes |
fast radio burst (frb) dispersion measures (dms) record the presence of ionized baryons that are otherwise invisible to other techniques enabling resolution of the matter distribution in the cosmic web. in this work, we aim to estimate the contribution to frb 180924 dm from foreground galactic halos. localized by askap... | estimating the contribution of foreground halos to the frb 180924 dispersion measure |
the cassini spacecraft revealed that saturn's magnetic field displayed oscillations at a period originally thought to match the planetary rotation rate but later found not to. one of many proposed theories predicts that a polar twin-cell neutral weather system drives this variation, producing observable differences in ... | saturn's weather-driven aurorae modulate oscillations in the magnetic field and radio emissions |
the millimeter-wave spectrum of the sip radical (x2πi) has been measured in the laboratory for the first time using direct-absorption methods. sip was created by the reaction of phosphorus vapor and sih4 in argon in an ac discharge. fifteen rotational transitions (j + 1 ← j) were measured for sip in the ω = 3/2 ladder ... | laboratory and astronomical detection of the sip radical (x2π i ): more circumstellar phosphorus |
beginning from the 1990s, an ever-lasting interest in the terahertz (thz) spectroscopy and thz instruments has produced wide progress in the development of high-speed thz detectors. the constantly growing requirements aimed at the increase of spectral resolution, sensitivity, and acquisition rate of thz detectors have ... | recent advances in thz detectors based on semiconductor structures with quantum confinement: a review |
photodetectors based on nano-structured superconducting thin films are currently some of the most sensitive quantum sensors and are key enabling technologies in such broad areas as quantum information, quantum computation and radio-astronomy. however, their broader use is held back by the low operation temperatures whi... | a high-tc van der waals superconductor based photodetector with ultra-high responsivity and nanosecond relaxation time |
the search for axions has gained ground in recent years, with laboratory searches for cold dark matter (cdm) axions, relativistic solar axions, and ultra-light axions as the subject of extensive literature. in particular, the interest in axions as cdm candidates has been motivated by their potential to account for all ... | a radio astronomy search for cold dark matter axions |
context. spectral lines of minor isotopic species of molecules that are abundant in space may also be detectable. their respective isotopic ratios may provide clues about the formation of these molecules. emission lines of acetone in the hot molecular core sagittarius b2(n2) are strong enough to warrant a search for it... | laboratory rotational spectroscopy of isotopic acetone, ch313c(o)ch3 and 13ch3c(o)ch3, and astronomical search in sagittarius b2(n2) |
in the next decade, new astrophysical instruments will deliver the first large-scale maps of gravitational waves (gws) and radio sources. therefore, it is timely to investigate the possibility to combine them to provide new and complementary ways to study the universe. using simulated catalogues appropriate to the plan... | gravitational wave astronomy with radio galaxy surveys |
how did galaxies form and evolve? this is one of the most challenging questions in astronomy today. answering it requires a careful combination of observational and theoretical work to reliably determine the observed properties of cosmic bodies over large portions of the distant universe on the one hand, and accurately... | help: the herschel extragalactic legacy project and the coming of age of multi-wavelength astrophysics |
closure phase is the phase of a closed-loop product of spatial coherences formed by a ${\ge}3$ -element interferometer array. its invariance to phase corruption attributable to individual array elements acquired during the propagation and the measurement processes, subsequent calibration, and errors therein, makes it a... | a geometric view of closure phases in interferometry |
we report the discovery of two black widow millisecond pulsars in the globular cluster (gc) m28 with the meerkat telescope. psr j1824-2452m (m28m) is a 4.78 ms pulsar in a 5.82 hr orbit, and psr j1824-2452n (m28n) is a 3.35 ms pulsar in a 4.76 hr orbit. both pulsars have dispersion measures near 119.30 pc cm-3 and have... | two new black widow millisecond pulsars in m28 |
space very long baseline interferometry (vlbi) has unique applications in high-resolution imaging of the fine structure of astronomical objects and high-precision astrometry due to the key long space-earth or space-space baselines beyond the earth's diameter. china has been actively involved in the development of space... | space very long baseline interferometry in china |
our understanding of the universe relies mostly on electromagnetism. as photons are the messengers, fundamental physics is concerned in testing their properties. photon mass upper limits have been earlier set through pulsar observations, but new investigations are offered by the excess of dispersion measure (dm), somet... | dispersion by pulsars, magnetars, fast radio bursts and massive electromagnetism at very low radio frequencies |
the accumulation of aberrations along the optical path in a telescope produces distortions and speckles in the resulting images, limiting the performance of cameras at high angular resolution. it is important to achieve the highest possible sensitivity to faint sources, using both hardware and data analysis software. w... | kernel phase and coronagraphy with automatic differentiation |
stratospheric observatory for infrared astronomy high-resolution airborne wideband camera plus polarimetry at 154 μm is reported for the face-on galaxy m51 and the edge-on galaxy ngc 891. for m51, the polarization vectors generally follow the spiral pattern defined by the molecular gas distribution, the far-infrared (f... | hawc+ far-infrared observations of the magnetic field geometry in m51 and ngc 891 |
we present observations of a region of the galactic plane taken during the early science program of the australian square kilometre array pathfinder (askap). in this context, we observed the scorpio field at 912 mhz with an uncompleted array consisting of 15 commissioned antennas. the resulting map covers a square regi... | evolutionary map of the universe (emu): compact radio sources in the scorpio field towards the galactic plane |
mounting evidence suggests that luminous fast blue optical transients (lfbots) are powered by a compact object, launching an asymmetric and fast outflow responsible for the radiation observed in the ultraviolet, optical, infrared, radio, and x-ray bands. proposed scenarios aiming to explain the electromagnetic emission... | neutrino emission from luminous fast blue optical transients |
solar-type protostars have been shown to harbor highly deuterated complex organics, as evidenced, for instance, by the high relative abundances of doubly and triply deuterated isotopologs. while this degree of deuteration may provide important clues in studying the formation of these species, spectroscopic information ... | rotational and rovibrational spectroscopy of cd3oh with an account of cd3oh toward iras 16293−2422 |
high brightness-temperature radiation is observed in various astrophysical sources: active galactic nuclei, pulsars, interstellar masers, and flaring stars; the discovery of fast radio bursts renewed interest in the nonlinear interaction of intense radiation with plasma. in astronomical systems, the radiation frequency... | nonlinear electromagnetic-wave interactions in pair plasma. i. nonrelativistic regime |
gravitational waves from binary neutron star mergers can be used as alerts to enable prompt follow-up observations. in particular, capturing prompt electromagnetic and astroparticle emissions from the moment of a binary merger presents unique constraints on the timescale and sky localization for online gravitational-wa... | early warnings of binary neutron star coalescence using the spiir search |
we present a detailed compilation and analysis of the x-ray phase space of low- to intermediate-redshift (0 ≤ z ≤ 1) transients that consolidates observed light curves (and theory where necessary) for a large variety of classes of transient/variable phenomena in the 0.3-10 kev energy band. we include gamma-ray burst af... | the luminosity phase space of galactic and extragalactic x-ray transients out to intermediate redshifts |
the most massive stars are thought to lose a significant fraction of their mass in a steady wind during the main-sequence and blue supergiant phases. this in turn sets the stage for their further evolution and eventual supernova, and preconditions the surrounding medium for all following events, with consequences for i... | understanding structure in line-driven stellar winds using ultraviolet spectropolarimetry in the time domain |
line intensity mapping (lim) is a new technique for tracing the global properties of galaxies over cosmic time. detection of the very faint signals from redshifted carbon monoxide (co), a tracer of star formation, pushes the limits of what is feasible with a total-power instrument. the co mapping project pathfinder is ... | comap early science. ii. pathfinder instrument |
in extreme scattering events, the brightness of a compact radio source drops significantly, as light is refracted out of the line of sight by foreground plasma lenses. despite recent efforts, the nature of these lenses has remained a puzzle, because any roughly round lens would be so highly overpressurized relative to ... | pulsar double lensing sheds light on the origin of extreme scattering events |
the fullerene c60, one of the largest molecules identified in the interstellar medium (ism), has been proposed to form top-down through the photochemical processing of large (more than 60 c atoms) polycyclic aromatic hydrocarbon (pah) molecules. in this article, we focus on the opposite process, investigating the possi... | laboratory photochemistry of covalently bonded fluorene clusters: observation of an interesting pah bowl-forming mechanism |
we report spatial distributions of the fe-kα line at 6.4 kev and the co(j = 2-1) line at 230.538 ghz in ngc 2110, which are, respectively, revealed by chandra and atacama large millimeter/submillimeter array (alma) at ≈0"5. a chandra 6.2-6.5 kev to 3.0-6.0 kev image suggests that the fe-kα emission extends preferential... | agn x-ray irradiation of co gas in ngc 2110 revealed by chandra and alma |
fast radio bursts (frbs), characterized by strong bursts of radiation intensity at radio wavelengths lasting on the order of a millisecond, have yet to be firmly associated with a family, or families, of astronomical sources. it follows that despite the large number of proposed models, no well-defined physical process ... | explaining fast radio bursts through dicke's superradiance |
lofar (low frequency array) is a new generation digitally controlled radio telescope consisting of phased array antenna stations with sensitivity, bandwidth, range of frequency, and digital processing power that makes it an excellent tool for observations of pulsars. this interferometric instrument is able to work in a... | prospects for scrutiny of pulsars with polish part of lofar |
the past decade has seen the advent of various radio astronomy arrays, particularly for low-frequency observations below 100 mhz. these developments have been primarily driven by interesting and fundamental scientific questions, such as studying the dark ages and epoch of re-ionization, by detecting the highly red-shif... | space-based aperture array for ultra-long wavelength radio astronomy |
quasiperiodic radio frequency interference (rfi), such as those generated by telecommunication and active radar systems, is commonly encountered in radio astronomy observations. such rfi-contaminated signals contain hidden periodicities due to cyclic features involved in their formation (e.g., carrier frequencies, peri... | radio frequency interference detection and mitigation using compressive statistical sensing |
context. the observed spatial scale of the radio continuum emission from star-forming galaxies can be used to investigate the spatial extent of active star formation, constrain the importance of cosmic-ray transport, and examine the effects of galaxy interactions.aims: we determine the radio size distribution of a larg... | an alma survey of submillimetre galaxies in the cosmos field: the extent of the radio-emitting region revealed by 3 ghz imaging with the very large array |
tracing the transition between the diffuse atomic interstellar medium and cold, dense gas is crucial for deciphering the star formation cycle in galaxies. here we present measuring absorption by cold hydrogen (mach), a new survey of cold neutral hydrogen (hi) absorption at 21 cm by the karl g. jansky very large array. ... | the mach hi absorption survey. i. physical conditions of cold atomic gas outside of the galactic plane |
we propose and apply a method to quantify the morphology of the large-scale ordered magnetic fields (b-fields) in galaxies. this method is adapted from the analysis of event horizon telescope polarization data. we compute a linear decomposition of the azimuthal modes of the polarization field in radial galactocentric b... | the structure of magnetic fields in spiral galaxies: a radio and far-infrared polarimetric analysis |
a new era of exploration of the low radio frequency universe from the moon will soon be underway with landed payload missions facilitated by nasa's commercial lunar payload services (clps) program. clps landers are scheduled to deliver two radio science experiments, radio wave observations at the lunar surface of the p... | low radio frequency observations from the moon enabled by nasa landed payload missions |
askap is an array of 36 radio antennas, located at the murchison radio observatory, in western australia. radio astronomy signals collected with the askap antennas are transferred to the pawsey supercomputing centre in perth where they are processed, archived, and made available to astronomers. astronomers interact wit... | casda: the csiro askap science data archive |
<p id="par1">the discovery in 1998 of the first accreting millisecond x-ray pulsar<index-term id="iterm1"><term>accreting millisecond pulsar</term></index-term> started an exciting season of continuing discoveries. in the last 20 years, thanks to the extraordinary performance of astronomic... | accretion powered x-ray millisecond pulsars |
apertif (aperture tile in focus) is one of the square kilometre array (ska) pathfinder facilities. the apertif project is an upgrade to the 50-year-old westerbork synthesis radio telescope (wsrt) using phased-array feed technology. the new receivers create 40 individual beams on the sky, achieving an instantaneous sky ... | apercal-the apertif calibration pipeline |
the european space agency's international gamma-ray astrophysics laboratory (esa/integral) was launched aboard a proton-dm2 rocket on 17 october 2002 at 06:41 cest, from baikonur in kazakhstan. since then, integral has been providing long, uninterrupted observations (up to about 47 h, or 170 ksec, per satellite orbit o... | integral reloaded: spacecraft, instruments and ground system |
the pure rotational spectrum of the elusive cn+ cation has been observed for the first time using a cryogenic ion trap apparatus and applying an action spectroscopy scheme. for the 12c14n+ species, the three lowest rotational transitions have been observed, each of which exhibits hyperfine structure from the presence o... | pure rotational spectrum of cn+ |
we have studied low-frequency (45 - 410 mhz) type iii solar radio bursts observed using the e-compound astronomical low-cost low-frequency instrument for spectroscopy and transportable observatory (e-callisto) spectrometer located at gauribidanur radio observatory, india, during 2013 - 2017. after inspecting 1531 type ... | a statistical study of low-frequency solar radio type iii bursts |
results of the application of pattern-recognition techniques to the problem of identifying giant radio sources (grss) from the data in the nvss catalog are presented, and issues affecting the process are explored. decision-tree pattern-recognition software was applied to training-set source pairs developed from known n... | a selection of giant radio sources from nvss |
in this study, we analyze giant galactic spurs seen in both radio and x-ray all-sky maps to reveal their origins. we discuss two types of giant spurs: one is the brightest diffuse emission near the map's center, which is likely to be related to fermi bubbles (npss/spss, north/south polar spurs, respectively), and the o... | origin of galactic spurs: new insight from radio/x-ray all-sky maps |
the construction of the seven-dish karoo array telescope (kat-7) array in the karoo region of the northern cape in south africa was intended primarily as an engineering prototype for technologies and techniques applicable to the meerkat telescope. this paper looks at the main engineering and scientific highlights from ... | engineering and science highlights of the kat-7 radio telescope |
the follow-up timing observations were carried out for 24 pulsars discovered with the five-hundred-meter aperture spherical radio telescope (fast) in commensal radio astronomy fast survey. we report their phase-connected timing ephemeris, polarization pulse profiles, and faraday rotation measurements. with their spin p... | follow-up timing of 24 pulsars discovered in commensal radio astronomy fast survey |
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