abstract stringlengths 3 192k | title stringlengths 4 857 |
|---|---|
the giant radio array for neutrino detection (grand) aims to answer one of the most pressing open questions in astrophysics: what is the origin of ultra-highenergy cosmic rays (uhecrs)?. it will do so indirectly: uhecrs make secondary uhe neutrinos which encode information about the properties of uhecrs and their sourc... | grand, a giant radio array for neutrino detection: objectives, design and current status |
detecting candidates of supernova remnants (snrs) in the interstellar medium is a challenging task because snrs have weak radio signals and irregular shapes. the use of a convolutional neural network is a deep learning method that can help us extract various features from images. to extract snrs from astronomical image... | deep learning for supernova remnants detection and localization |
radio astronomy uses radio telescopes to detect very faint emissions from celestial objects. however, human-made radio frequency interference (rfi) is currently a common problem faced by most terrestrial radio telescopes, and it is getting worse with the development of the economy and technology. therefore, it is essen... | a software for rfi analysis of radio environment around radio telescope |
the legacy ooty radio telescope (ort) is being reconfigured as a 264-element synthesis telescope, called the ooty wide field array (owfa). its antenna elements are the contiguous 1.92 m sections of the parabolic cylinder. it will operate in a 38-mhz frequency band centred at 326.5 mhz and will be equipped with a digita... | the receiver system for the ooty wide field array |
radiation pressure exerted by light on any surface is the pressure generated by the momentum of impinging photons. the associated force - fundamentally, a quantum mechanical aspect of light - is usually too small to be useful, except in large-scale problems in astronomy and astrodynamics. in atomic and molecular optics... | micromechanical resonator driven by radiation pressure force |
we describe radio, optical, and x-ray observations of this rather faint, old large magellanic cloud (lmc) supernova remnant. the [o iii] emission forms a distinct shell, the remnant of the outer shock, which encloses the radio and x-ray emission and gives an estimate of age and explosion energy. because of a collision ... | the large magellanic cloud supernova remnant mcsnr j0550-6823 |
if fast radio bursts (frbs) originate from galaxies at cosmological distances, then their all-sky rate implies that the milky way may host an frb every 30-1500 yr, on average. if many frbs persistently repeat for decades or more, a local giant frb could be active now, with 1 ghz radio pulses of flux ∼3 × 1010 jy, compa... | searching for giga-jansky fast radio bursts from the milky way with a global array of low-cost radio receivers |
we present an improvement of our implementation of the correlation technique for the fourier domain acceleration search (fdas) algorithm on graphics processor units (gpus) (dimoudi & armour 2015; dimoudi et al. 2017). our new improved convolution code which uses our custom gpu fft code is between 2.5 and 3.9 times ... | improved acceleration of the gpu fourier domain acceleration search algorithm |
the uv-coverage of the current vlbi network between australia northern asia will be significantly enhanced with an existence of a middle baseline vlbi station located in malaysia. this paper investigated the connecting route of the first half of the asia-oceania vlbi network i.e. from malaysia to china. the investigati... | radio astronomy interferometer network testing for a malaysia-china real-time e-vlbi |
since the first laboratory synthesis of c60 in 1985, fullerene-related species have been proposed to interpret various astronomical features. after more than 25 years' efforts, several circumstellar and interstellar features have been convincingly assigned to c60, c70, and c60+. these successes resulted from the recent... | hydrogenated fullerenes (fulleranes) in space |
we present montblanc, a gpu implementation of the radio interferometer measurement equation (rime) in support of the bayesian inference for radio observations (biro) technique. biro uses bayesian inference to select sky models that best match the visibilities observed by a radio interferometer. to accomplish this, biro... | montblanc1: gpu accelerated radio interferometer measurement equations in support of bayesian inference for radio observations |
we report development of a simple and affordable radio interferometer suitable as an educational laboratory experiment. the design of this interferometer is based on the michelson and pease stellar optical interferometer, but instead operates at the radio wavelength of ∼11 ghz (∼2.7 cm), requiring much less stringent o... | a michelson-type radio interferometer for university education |
the supernova remnant g51.26+0.11 was recently discovered and little is known about its properties and environment. using data from the fermi large area telescope we study the gev emission seen in the direction of g51.26+0.11 to constrain the origin of the gamma-rays and their possible relation to this supernova remnan... | gev emission in the region of the supernova remnant g51.26+0.11 |
we present new molecular gas maps of ngc 5195 (alternatively known as m51b) from the combined array for research in millimeter astronomy, including 12co(1-0), 13co(1-0), cn(1{}{0,2}-{0}{0,1}), cs(2-1), and 3 mm continuum. we also detected hcn(1-0) and hco+(1-0) using the onsala space observatory. ngc 5195 has a 12co/13... | after the interaction: an efficiently star-forming molecular disk in ngc 5195 |
the radio-astro-tools organization has been established to facilitate development of radio and millimeter analysis tools by the scientific community. the first packages developed under its umbrella are: • the spectral-cube package, for reading, writing, and analyzing spectral data cubes • the pvextractor package for ex... | radio astronomy tools in python: spectral-cube, pvextractor, and more |
context. most popular algorithms in use to remove the effects of a telescope's point spread function (psf) in radio astronomy are variants of the clean algorithm. most of these algorithms model the sky brightness using the delta-function basis, which results in undesired artefacts when used to image extended emission. ... | efficient implementation of the adaptive scale pixel decomposition algorithm |
the us naval research laboratory (nrl) and the national radio astronomy observatory (nrao) have collaborated to develop, install, and commission a new commensal system on the karl g. jansky very large array (vla). the vla low band ionospheric and transient experiment (vlite) makes use of dedicated samplers and fibers t... | the vla low band ionospheric and transient experiment (vlite): a commensal sky survey |
one of the principal challenges of 21 cm cosmology experiments is overcoming calibration error. established calibration approaches in the field require an exquisitely accurate sky model, and low-level sky model errors introduce calibration errors that corrupt the cosmological signal. we present a novel calibration appr... | delay-weighted calibration: precision calibration for 21 cm cosmology with resilience to sky model error |
regularized maximum likelihood (rml) techniques are a class of image synthesis methods that achieve better angular resolution and image fidelity than traditional methods like clean for sub-mm interferometric observations. to identify best practices for rml imaging, we used the gpu-accelerated open source python package... | regularized maximum likelihood image synthesis and validation for alma continuum observations of protoplanetary disks |
data from radio interferometers provide a substantial challenge for statisticians. it is incomplete, noise-dominated and originates from a non-trivial measurement process. the signal is not only corrupted by imperfect measurement devices but also from effects like fluctuations in the ionosphere that act as a distortion... | radio imaging with information field theory |
magnetic fields play essential roles in various astronomical objects. radio astronomy has revealed that magnetic fields are ubiquitous in our universe. however, the real origin and evolution of magnetic fields is poorly proven. in order to advance our knowledge of cosmic magnetism in coming decades, the square kilometr... | resolving 4-d nature of magnetism with depolarization and faraday tomography: japanese ska cosmic magnetism science |
the depth-dependent abundance of both gas-phase and solid-state water within dense, quiescent, molecular clouds is important to both the cloud chemistry and gas cooling. where water is in the gas phase, it is free to participate in the network of ion-neutral reactions that lead to a host of oxygen-bearing molecules, an... | distribution of water vapor in molecular clouds. ii |
pulsars (psrs) orbiting intermediate or supermassive black holes at the centre of galaxies and globular clusters are known as extreme mass ratio binaries (emrbs) and have been identified as precision probes of strong-field gr. for appropriate orbital parameters, some of these systems may also emit gravitational radiati... | gravitational burst radiation from pulsars in the galactic centre and stellar clusters |
pulsar timing arrays (ptas) are anticipated to detect the stochastic gravitational-wave background (gwb) from supermassive binary black holes (bbhs) as well as the gravitational waves from individual bbhs. recently, a common process signal was reported by several ptas. in this paper, we investigate the constraints on t... | pulsar timing array detections of supermassive binary black holes: implications from the detected common process signal and beyond |
we have designed a low-cost radio telescope system named the bose horn antenna radio telescope (bharat) to detect the 21 cm hydrogen line emission from our galaxy. the system is being used at the radio physics laboratory (rpl), inter-university centre for astronomy and astrophysics (iucaa), india, for laboratory sessio... | a bose horn antenna radio telescope (bharat) design for 21 cm hydrogen line experiments for radio astronomy teaching |
many gamma-ray bursts (grbs) have been observed from radio wavelengths, and a few at very high energies (vhes, >100 gev). the high altitude water cherenkov (hawc) gamma-ray observatory is well suited to study transient phenomena at vhes owing to its large field of view and duty cycle. these features allow for search... | constraints on the very high energy gamma-ray emission from short grbs with hawc |
we perform correlation and periodicity search analyses on long-term multiband light curves of the flat-spectrum radio quasar pks 1510-089 observed by the space-based fermi-large area telescope in γ-rays, the smarts and steward observatory telescopes in optical and near-infrared (nir), and the 13.7 m radio telescope in ... | multiwavelength temporal variability of the blazar pks 1510-089 |
einstein's general relativity (gr) is the basis of modern astronomy and astrophysics. testing the validity of basic assumptions of gr is important. in this work, we test a possible violation of the weak equivalence principle (wep), i.e. there might be a time lag between photons of different frequencies caused by the ef... | constraining violations of the weak equivalence principle using chime frbs |
in pulsar signal processing, two primary difficulties are (1) radio-frequency interference (rfi) mitigation and (2) information loss due to preprocessing and mitigation itself. linear mitigation methods have a difficulty in rfi modeling, and accommodate a limited range of rfi morphologies. thresholding methods suffer f... | compressed sensing based rfi mitigation and restoration for pulsar signals |
we present the first comprehensive study of nacl and kcl gases in io's atmosphere in order to investigate their characteristics and infer properties of io's volcanoes and subsurface magma chambers. in this work, we compile all past spectral line observations of nacl and kcl in io's atmosphere from the atacama large mil... | nacl and kcl in io's atmosphere |
the national radio astronomy observatory (nrao) has engaged the broad scientific and technical communities in the design of a next-generation very large array [1] (ngvla), a large-scale research infrastructure project under development for the national science foundation astronomical sciences division (nsf-ast) through... | the ngvla: a technical development update |
caballero identified the star 2mass 19281982-2640123 as a potential sun-like star from which the wow! signal could have originated. we conducted a search for artificial narrowband (2.79 hz/1.91 hz), drifting (±4 hz s-1) technosignatures from this source using the turboseti pipeline, from 1-2 ghz, using simultaneous mul... | breakthrough listen search for the wow! signal |
we present the discovery of the simultaneous flux variation of a massive young stellar object (myso) g036.70+00.09 (g036.70) both in the maser emission and mid-infrared (mir; λ = 3-5 μm) bands. using the allwise and neowise archival databases that cover a long time span of approximately 10 yr with a cadence of 6 months... | mid-infrared and maser flux variability correlation in massive young stellar object g036.70+00.09 |
a search has been made for 21 cm h i line emission in a total of 350 unique galaxies from two samples whose optical properties indicate they may be massive. the first consists of 241 low surface brightness (lsb) galaxies of morphological type sb and later selected from the hyperleda database and the second consists of ... | searching in h i for massive low surface brightness galaxies: samples from hyperleda and the ugc |
powerful radio sources associated with supermassive black holes are among the most luminous objects in the universe, and are frequently recognized both as cosmological probes and active constituents in the evolution of galaxies. we present alignments between radio jets and cold molecular gas in the environment of dista... | co survey of high-z radio galaxies, revisited with the atacama large millimeter/submillimeter array: jet-cloud alignments and synchrotron brightening by molecular gas in the circumgalactic environment |
blazars are active galactic nuclei whose ultra-relativistic jets are co-aligned with the observer direction. they emit throughout the whole e.m. spectrum, from radio waves to vhe gamma rays. not all blazars are discovered. in this work, we propose a catalog of new highly probable candidates based on the association of ... | a catalog of new blazar candidates with open universe by high school students |
the international vlbi service for geodesy and astrometry (ivs) regularly provides high-quality data to produce earth orientation parameters (eop), and for the maintenance and realisation of the international terrestrial and celestial reference frames, itrf and icrf. the first iteration of the celestial reference frame... | on more than two decades of celestial reference frame vlbi observations in the deep south: ivs-crds (1995-2021) |
we present millimeter and submillimeter continuum observations for 36 sources with potentially large black hole shadows at 230 and 345 ghz using the submillimeter array. the sources are selected based on the criterion of the large diameter of the black hole shadows. our motivation is to explore the nature of the accret... | surveying flux density in galaxies with apparent large black holes at millimeter/submillimeter wavelengths |
we perform a series of time-dependent magnetohydrodynamic simulations of the hd 189733 star-planet system in order to predict radio transit modulations due to the interaction between the stellar wind and planetary magnetic field. the simulation combines a model for the stellar corona and wind with an exoplanet that is ... | exoplanet radio transits as a probe for exoplanetary magnetic fields-time-dependent mhd simulations |
modern astronomers enjoy access to all-sky images across a wide range of the electromagnetic spectrum from long-wavelength radio to high-energy gamma rays. the most prominent feature in many of these images is our own galaxy, with different features revealed in each wave band. gravitational waves (gws) have recently be... | imaging the milky way with millihertz gravitational waves |
in this tutorial we summarize the physics and mathematics behind refractive electromagnetic wave bending and delay. refractive bending and delay through the earth's atmosphere at both radio/millimetric and optical/ir wavelengths are discussed, but with most emphasis on the former, and with atacama large millimeter arra... | atmospheric refractive electromagnetic wave bending and propagation delay |
a search for long-term variability in three flat-spectrum sources has been carried out using monitoring data obtained over 5.5 years on the large phased array of the pushchino radio astronomy observatory. variability was detected at low frequencies in all three sources. a noise signal with known temperature was used to... | search for long-term variability of several flat-spectrum sources at 111 mhz |
we present observations of quiet-sun small-scale structures (sss) in the microwave range with the radio astronomical telescope of the academy of sciences 600 (ratan-600) spectral-polarization facility in a wide range of frequencies. the sss are regularly recorded in routine observations of the large reflector-type radi... | ratan-600 observations of small-scale structures with high spectral resolution |
we have analyzed the thermal and turbulent properties of the low-latitude intermediate-velocity arch 1 (lliv1). this was accomplished using archival h i emission and absorption data from two 21 cm line surveys: ghigls at 9.'4 resolution and dhigls at $1^{\prime} $ resolution. the spectral decomposition code rohsa was u... | mapping the multiphase structure of h i in the low-latitude intermediate-velocity arch 1 |
a new digital receiver with excellent performances has been designed and developed for solar radio observation, which can receive the radio signal from direct current (dc) to 9 ghz in the direct acquisition way. on the digital receiver, the analog-to-digital converter (adc) with 14-bit, two input channels and 3 giga sa... | a 3 giga sample per second 14-bit digital receiver with 9 ghz input bandwidth for solar radio observation |
in this paper, a microwave interferometer prototype with a near-infra-red optical correlator is proposed as a solution to get a large-format interferometer with hundreds of receivers for radio astronomy applications. a 10 gbits/s lithium niobate modulator has been tested as part of an electro-optic correlator up-conver... | electro-optic correlator for large-format microwave interferometry: up-conversion and correlation stages performance analysis |
the five-hundred-meter aperture spherical radio telescope (fast) is a chinese mega-science project to build the largest single dish radio telescope in the world. a unique karst depression in guizhou province has been selected as the site to build an active reflector radio telescope with a diameter of 500 m and three ou... | fast construction progress |
fundamentals of microwave photonics provides a comprehensive description of analog optical links from basic principles to applications. the book is organized into four parts. the first begins with a historical perspective of microwave photonics, listing the advantages of fiber optic links and delineating analog vs. dig... | fundamentals of microwave photonics |
the article presents the results of observations of the blazar 3c 454.3 (j2253+1608), obtained in 2010-2017 on the ratan-600 radio telescope of the special astrophysical observatory at 4.6, 8.2, 11.2, and 21.7 ghz and on the 32-m zelenchuk and badary radio telescopes of the quasar vlbi network of the institute of appli... | long-term and rapid radio variability of the blazar 3c 454.3 in 2010-2017 |
until karl jansky's 1933 discovery of radio noise from the milky way, astronomy was limited to observation by visible light. radio astronomy opened a new window on the universe, leading to the discovery of quasars, pulsars, the cosmic microwave background, electrical storms on jupiter, the first extrasolar planets, and... | star noise: discovering the radio universe |
detection of epoch of reionization (eor) signal by measuring the redshifted 21-cm emission line is a key science project of the lofar radio telescope. this requires highly accurate signal (data) processing as well as 'big data' high performance computing (hpc) on more than thousand hours of astronomical observations. w... | an integrated hpc system for the lofar eor project |
compact astronomical low-frequency, low-cost instrument for spectroscopy in transportable observatories (callisto) is a global network of spectrometer system with the purpose to observe the sun's activities. there are 37 stations (using 68 instruments) forming this network from more than 96 countries. we investigate th... | radio frequency interference in solar monitoring using callisto |
this paper describes the latest development of a w-band 90 nm-cmos receiver chip that is suitable for use in radio-astronomical multi-pixel imaging arrays and other broadband scientific instruments. this circuit includes an rf-low-noise amplifier (lna), mixer, intermediate-frequency amplifier (if-amp), local-oscillator... | a 90 nm-cmos broadband receiver with 10 db conversion gain and 15 db noise figure in 80-110 ghz suitable for multi-pixel imaging arrays |
pulsars are magnetized and very dense neutron stars. their very high moment of inertia renders them with an extraordinarily stable rotation, making pulsars one of the most accurate clocks in the universe. however, the rotational stability of some pulsars is disturbed by glitches, which consist of a sudden increase of t... | detección de un glitch en psr j1048-5832 desde el iar |
we present a relatively simple time domain method for determining the bandpass response of a system by injecting a nanosecond pulse and capturing the system voltage output. a pulse of sub-nanosecond duration contains all frequency components with nearly constant amplitude up to 1 ghz. hence, this method can accurately ... | bandpass calibration of a wideband spectrometer using coherent pulse injection |
aims: messier 8 (m8) is one of the brightest hii regions in the sky. we collected an extensive dataset comprising multiple sub- millimeter spectral lines from neutral and ionized carbon and from co. based on this dataset, we aim to understand the morphology of m8 and that of its associated photodissociation region (pdr... | unveiling the remarkable photodissociation region of messier 8 |
we present a study of decimetric radio activity using the first high time cadence (0.5 s) images from the giant meterwave radio telescope (gmrt) at 610 mhz associated with goes c1.4- and m1.0-class solar flares and a coronal mass ejection (cme) onset that occurred on 2015 june 20. the high spatial resolution images fro... | decimetric emission 500″ away from a flaring site: possible scenarios from gmrt solar radio observations |
we present results of our chandra/acis observations of the field centered on the fast, runaway o star ae aur and its bow shock. previous xmm-newton observations revealed an x-ray “blob” near the ir arc tracing the bow shock, possibly a nonthermal source consistent with models of inverse compton scattering of dust ir ph... | runaway o-star bow shocks as particle accelerators? the case of ae aur revisited |
the north american astronomical community is considering a future large area radio array optimized to perform imaging of thermal emission down to milliarcsecond scales. this `next generation very large array' would entail ten times the effective collecting area of the jansky very large array, operate from 1ghz to 115gh... | the next generation very large array |
binary pulsars are an important target for radio surveys because they present a natural laboratory for a wide range of astrophysics for example testing general relativity, including detection of gravitational waves. the orbital motion of a pulsar which is locked in a binary system causes a frequency shift (a doppler sh... | searching for pulsars in extreme orbits - gpu acceleration of the fourier domain 'jerk' search |
the formaldehyde h2co(110-111) absorption line and h110α radio recombination line have been observed toward the aquila molecular cloud using the nanshan 25 m telescope operated by the xinjiang astronomical observatory cas. these first observations of the h2co (110-111) absorption line determine the extent of the molecu... | h2co and h110α observations toward the aquila molecular cloud |
30 doradus c is a superbubble that emits the brightest non-thermal x- and tev gamma-rays in the local group. to explore the detailed connection between the high-energy radiation and the interstellar medium, we have carried out new co and hi observations using the atacama large millimeter/submillimeter array (alma), ata... | associated molecular and atomic clouds with x-ray shell of superbubble 30 doradus c in the lmc |
the paper presents the main results of the implementation of the radioastron early science program. interferometric responses (fringes) were obtained for all types of studied radio sources (quasars, pulsars and cosmic masers) and in all ranges of wavelengths (from meter to centimeter range) with large spaceground basel... | radioastron: main results of the implementation of the early science program in studies of astronomical objects in the universe with ultra-high angular resolution |
we report the redshift of an unlensed, highly obscured submillimetre galaxy (smg), hs1700.850.1, the brightest smg (s850 μm = 19.1 mjy) detected in the james clerk maxwell telescope/submillimetre common-user bolometer array-2 (jcmt/scuba-2) baryonic structure survey, based on the detection of its 12co line emission. us... | a millimetre-wave redshift search for the unlensed hylirg, hs1700.850.1 |
we report a 325(-7, +8) day quasi-periodic oscillation (qpo) in the x-ray emission of the blazar mkn 421 based on data obtained with the rossi x-ray timing explorer satellite. the qpo is seen prominently in the asm data (at least 15 cycles) due to the fact that it has had near-continuous sampling for more than a decade... | a qpo in mkn 421 from archival rxte data |
context. the ketenyl radical hcco has recently been detected in the interstellar medium (ism) for the first time. further astronomical detections of hcco will help us understand its gas-grain chemistry, and subsequently revise the oxygen-bearing chemistry towards dark clouds. moreover, its deuterated counterpart dcco h... | rotational spectroscopy of the hcco and dcco radicals in the millimeter and submillimeter range |
that the laws of physics are the same at all times and places throughout the universe is one of the basic assumptions of physics. astronomical observations provide the only means to test this basic assumption on cosmological time and distance scales. the possibility of variations in the dimensionless physical constant ... | astrophysical constraints on the proton-to-electron mass ratio with fast |
low-frequency radio surveys allow in-depth studies and new analyses of classes of sources that were previously known and characterized only in other bands. in recent years, low radio frequency observations of blazars have become available as a result of new surveys, such as the galactic and extragalactic all-sky murchi... | radio spectral properties of cores and extended regions in blazars in the mhz regime |
we present the beta release of idavie-v, a new virtual reality software for data cube exploration. the beta release of idavie-v (immersive data visualisation interactive explorer for volumetric rendering) is planned for release in early 2021. idavie-v has been developed through the unity game engine using the steamvr p... | idavie-v: immersive data visualisation interactive explorer for volumetric rendering |
in the near future, two radio telescopes will be installed in the indonesian region. these telescopes are proposed to be integrated into the existing very long baseline interferometry (vlbi) network both for astronomical and geodetical purposes. here we simulate the impact of the inclusion of the future indonesian ante... | measuring the impact of indonesian antennas on global geodetic vlbi network |
we searched for a short-term x-ray variability of the m87 core and jet from archival x-ray data with long exposure data taken by the suzaku, chandra, and nustar telescopes. we found the intraday variability for the suzaku data obtained in 2006, and for the chandra core obtained in 2017. the intraday variability suggest... | the study of x-ray flux variability of m87 |
we test the accuracy of alma flux density calibration by comparing alma flux density measurements of extragalactic sources to measurements made by the planck mission; planck is absolutely calibrated to subpercent precision using the dipole signal induced by the satellite's orbit around the solar system barycenter. plan... | confirming the calibration of alma using planck observations |
we discuss the challenges that real-time radio transient surveys face from the perspective of one of the projects currently scanning the sky. meertrap is a commensal pulsar and fast transients survey that is being conducted using meerkat - a precursor to the square kilometre array, consisting of 64 dishes in south afri... | accelerating radio astronomy with high performance computing |
high-z blazars (z ≥ 2.5) are the most powerful class of persistent γ-ray sources in the universe. these objects possess the highest jet powers and luminosities and have black hole masses often in excess of 109 solar masses. in addition, high-z blazars are important cosmological probes and serve as test objects for blaz... | search for high-redshift blazars with fermi/lat |
the fundamental celestial reference frame (crf) is based on two catalogs of astrometric positions: the third realization of the international celestial reference frame (icrf3), and the much larger gaia crf, built from the third data release (dr3). the objects in common between these two catalogs are mostly distant agns... | radio-optical reference catalog, version 1 |
we study the evolution of a nonrelativistically expanding thin shell in radio-emitting tidal disruption events (tdes) based on a one-dimensional spherically symmetric model considering the effect of both a time-dependent mass-loss rate of the disk wind and the ambient mass distribution. the analytical solutions are der... | disk wind-driven expanding radio-emitting shell in tidal disruption events |
the aim of this work was to continue the monitoring of the h2o maser emission in iras 16293-2422 to detect superflares. we have been observing h2o maser emission at a wavelength of 1.35 cm towards the source iras 16293-2422 since 1999. the observations have been carried out with the 22-m radio telescope of the pushchin... | evolution of superflares of h2o maser emission in iras 16293-2422 |
aims: molecular masers, including methanol and hydroxyl masers, and in particular the ones in excited rotational states (ex-oh masers), are one of the most informative tools for studying star-forming regions. so, the discovery, of new maser sources in these regions is of great importance. many studies and surveys of ex... | new ex-oh maser detections in the northern celestial hemisphere |
several new radio facilities have a field of view and sensitivity well suited for transient searches. this makes it more important than ever to accurately determine transient rates in radio surveys. the work presented here seeks to do this task by using monte-carlo simulations. in particular, the user inputs either a r... | transient simulations for radio surveys |
it has become commonplace in astronomy to describe the transverse coarse structure of jets in loosely defined terms such as "sheath" and "spine" based on discussions of parsec scale properties. but, the applicability, dimension, and prominence of these features on sub-light-year scales has previously been unconstrained... | the details of limb brightening reveal the structure of the base of the jet in m87 for the first time |
the search for extraterrestrial intelligence (seti) commensal surveys aim to scan the sky to find possible technosignatures from an extraterrestrial intelligence (eti). the mitigation of radio frequency interference (rfi) is an important step, especially for the most sensitive five-hundred-meter aperture spherical radi... | a search for extraterrestrial technosignatures in archival fast survey data using a new procedure |
context. rising interest in radio astronomy and upcoming projects in the field is expected to produce petabytes of data per day, questioning the applicability of traditional radio astronomy data analysis approaches under the new large-scale conditions. this requires new, intelligent, fast, and efficient methods that po... | challenging interferometric imaging: machine learning-based source localization from uv-plane observations |
acetone-13c1 is a complex organic molecule with two internal methyl (-ch3) rotors having relatively low effective barriers to internal rotation of about 249 cm-1. this leads to two low-lying torsional modes and five internal rotation components resulting in a dense and complicated spectrum. in this study, measurements ... | llwp-a new loomis-wood software at the example of acetone-13c1 |
we present a study of scintillation induced by the mid-latitude ionosphere. by implementing methods currently used in interplanetary scintillation studies to measure amplitude scintillation at low frequencies, we have proven it is possible to use the murchison widefield array to study ionospheric scintillation in the w... | a measurement of small-scale features using ionospheric scintillation. comparison with refractive shift measurements |
we report on our proposal to develop an upgrade for the existing 211-275 ghz alma band 6 receiver, referred to as "band 6v2", which complies with the strategies defined in the alma development roadmap to 2030 and with the recommendations of the alma front-end & digitizer requirements upgrade working group. the goal... | alma band6v2 receiver upgrade |
the estimation of the direction of electromagnetic (em) waves from a radio source using electrically short antennas is one of the challenging problems in the field of radio astronomy. in this paper we have developed an algorithm which performs better in direction and polarization estimations than the existing algorithm... | snapshot averaged matrix pencil method (sam) for direction of arrival estimation |
in this short communication the selection rules for transitions involving asymmetry split energy levels belonging to various torsional-vibrational-rotational states are put forward for the first time in asymmetrically deuterated methanol species (e.g., ch2 doh , chd2 oh , etc.). unlike the parent symmetrical methanol s... | parity dependent selection rules, unexpected asymmetry splitting in methanol-d1(ch2 doh): observations on very high-resolution synchrotron (magneto-bremsstrahlung) radiation far-infrared spectrum |
the measured results of the antenna efficiency, sensitivity, and system noise temperature for tm65m telescope are reported in this paper. the key parameters describing a radio astronomy receiving system are introduced firstly. then the measurement methods are discussed, and the errors are assessed. finally, the measure... | antenna performance measurements in l, s, c, and x bands for tm65m radio telescope |
dealing with astrophysics derived from the radiation emitted by radioactive atomic nuclei, this book describes the different methods used to measure cosmic radio-isotopes. it demonstrates how this astronomical window has contributed to the understanding of the sources and the chemical evolution of cosmic gas. reference... | astrophysics with radioactive isotopes |
point source detection techniques are used to identify and localise point sources in radio astronomical surveys. with the development of the square kilometre array (ska) telescope, survey images will see a massive increase in size from gigapixels to terapixels. point source detection has already proven to be a challeng... | point proposal network: accelerating point source detection through deep learning |
investigations related to the impact caused by solar radio burst emissions on space weather forecasting and human activities have been ongoing for a long time. solar activities based on radio spectra are recorded by using a radio spectrometer from ground earth. currently, manual observations are conducted for burst det... | burst-finder: burst recognition for e-callisto spectra |
short channel field effect transistors can detect terahertz radiation. such detection is enabled by the excitation of the plasma waves rectified due to the device nonlinearities. the resulting response has nanometer scale spatial resolution and can be modulated in the sub thz range. this technology could enable a varie... | terahertz electronics for sensing and imaging applications |
the article presents the relevance and advantages of the new gamma observatory taiga (tunka advanced instrument for cosmic ray physics and gamma astronomy), which is being constructed in the tunka valley 50 km from lake baikal. various detectors of the six taiga gamma observatory arrays register the cherenkov and radio... | the taiga experiment: from cosmic ray physics to gamma astronomy in the tunka valley |
the lines observed in the spectra of astronomical objects provide unique information about them. currently, only one radio line has been detected in the spectrum of the sun: a hydrogen fine structure line 22p3/2-22s1/2 at the frequency 9845 mhz (3.05 cm). it was also found that in the spectrum of solar active formation... | recombination radio lines of the sun |
we investigate the question of the nature of compact stars, considering they may be neutron stars or hybrid stars containing a quark core, within the present constraints given by gravitational waves, radio-astronomy, x-ray emissions from millisecond pulsars and nuclear physics. a bayesian framework is used to combine t... | characteristics of compact stars determined by gravitational waves, radio-astronomy, x-ray emission, and nuclear physics |
written in python and utilising parseltongue to interface with the astronomical image processing system (aips), the e-merlin data reduction pipeline is intended to automate the procedures required in processing and calibrating radio astronomy data from the e-merlin correlator. driven by a plain text file of input param... | the e-merlin data reduction pipeline |
we probe the structure and kinematics of two neighbouring h ii regions identified as cometary and bipolar, using radio recombination lines (rrls). the h172α rrls from these h ii regions: g351.69-1.15 and g351.63-1.25, are mapped using giant metrewave radio telescope, india. we also detect carbon rrls c172α towards both... | gas kinematics in the h ii regions g351.69-1.15 and g351.63-1.25 |
type iii solar radio bursts form a well known class of active solar emissions and are associated with energetic electron beams propagation outwards through the coronal plasma, and in the process giving rise to their characteristic rapid spectral drifts. though they have been the subject of a large number of studies sin... | first detailed polarimetric study of type iii solar radio bursts with the murchison widefield array |
fermi-lat's detection of γ-rays from narrow-line seyfert 1 galaxies (nls1s) has received increasing attention. understanding these γ-nls1s is of interest because they have some properties similar to blazars, which are known to show rapid and large-amplitude variability. based on the largest sample of γ-nls1s (25 source... | a search for rapid mid-infrared variability in gamma-ray-emitting narrow-line seyfert 1 galaxies |
we study physical consequences of the hubble expansion of friedmann-lemaıtre-robertson-walker (flrw) manifold on measurement of space, time and light propagation in the local inertial frame. we use the results of this study to analyse the solar system radar ranging and doppler tracking experiments and time synchronizat... | local gravitational physics of the hubble expansion. einstein's equivalence principle in cosmology |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.