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in contrast to the converging, achromatic behaviour of axisymmetric gravitational lenses, diverging frequency-dependent lensing occurs from refraction due to a distribution of overdense axisymmetric plasma along an observer's line of sight. such plasma lenses are particularly interesting from the point of view of astro... | dual-component plasma lens models |
we present results of optical-uv observations of the 200 myr old rotation-powered radio pulsar j0108-1431 with the hubble space telescope. we found a putative candidate for the far-uv (fuv) pulsar counterpart, with the flux density fν = 9.0 ± 3.2 njy at λ = 1528 å. the pulsar was not detected, however, at longer wavele... | hubble space telescope observations of the old pulsar psr j0108-1431 |
the pulsar backend of the canadian hydrogen intensity mapping experiment has monitored hundreds of known pulsars in the northern sky since fall 2018, providing a rich data set for the study of temporal variations in pulsar emission. using a matched filtering technique, we report, for the first time, nulling behavior in... | the discovery of nulling and mode-switching pulsars with chime/pulsar |
faraday complexity describes whether a spectropolarimetric observation has simple or complex magnetic structure. quickly determining the faraday complexity of a spectropolarimetric observation is important for processing large, polarised radio surveys. finding simple sources lets us build rotation measure grids, and fi... | interpretable faraday complexity classification |
a new solution to the fermi paradox is presented: probes or visits from putative alien civilizations have a very low probability until a civilization reaches a certain age (called the "contact era") after the onset of radio communications. if biotic planets are common, putative advanced civilizations may send probes no... | the fermi paradox revisited: technosignatures and the contact era |
the search for extraterrestrial intelligence aims to find evidence of technosignatures, which can point toward the possible existence of technologically advanced extraterrestrial life. radio signals similar to those engineered on earth may be transmitted by other civilizations, motivating technosignature searches acros... | a simultaneous dual-site technosignature search using international lofar stations |
most fast radio burst (frb) models are built from comparatively common astronomical objects: neutron stars, black holes, and supernova remnants. yet frb sources are rare, and most of these objects, found in the galaxy, do not make frb. special and rare circumstances may be required for these common objects to be source... | a fast radio burst in a globular cluster: why is this neutron star different from (almost) all other neutron stars? |
stars provide an enormous gain for interstellar communications at their gravitational focus, perhaps as part of an interstellar network. if the sun is part of such a network, there should be probes at the gravitational foci of nearby stars. if there are probes within the solar system connected to such a network, we mig... | a search for radio technosignatures at the solar gravitational lens targeting alpha centauri |
low-noise microwave amplifiers are crucial for detecting weak signals in quantum technologies and radio astronomy. building an ideal device is challenging as it must amplify a broad range of frequencies while adding minimal noise. the amplification must also be directional so that it favors the observer's direction whi... | directional josephson traveling-wave parametric amplifier via non-hermitian topology |
amego-x, the all-sky medium energy gamma-ray observatory explorer, is a proposed instrument designed to bridge the so-called "mev gap" by surveying the sky with unprecedented sensitivity from ~100 kev to about 1 gev. this energy band is of key importance for multimessenger and multiwavelength studies but it is neverthe... | improving the low-energy transient sensitivity of amego-x using single-site events |
auroral kilometric radiation (akr) is the paradigm of intense radio emission from planetary magnetospheres. being close to the electron gyro frequency and/or its lower harmonics, its observation indicates the non-thermal state of the source plasma. emission is produced when the plasma enters a state of energetic excita... | auroral kilometric radiation—the electron cyclotron maser paradigm |
electrostatic (es) wave instabilities are assumed to be at the origin of radio emissions from interplanetary shocks, and solar coronal sources are most likely induced by electron beams, more energetic but less dense than electron strahls in the solar wind. in this paper, we present the results of a new dispersion and s... | kappa-distributed electrons in solar outflows: beam-plasma instabilities and radio emissions |
in this work, we study how to infer the orbit of a supermassive black hole binary (smbhb) by time-dependent measurements with very long baseline interferometry, such as the event horizon telescope (eht). assuming a pointlike luminosity image model, we show that with multiple years of observations by eht, it is possible... | orbit tomography of binary supermassive black holes with very long baseline interferometry |
nasa is working with us industry and academia to develop photonic integrated circuits (pics) for: (1) sensors (2) analog rf applications (3) computing and free space communications. the pics provide reduced size, weight, and power that is critical for space-based systems. we describe recent breakthrough 3d monolithic i... | integrated photonics for nasa applications |
recent observations are shedding light on the important role that active galactic nuclei play in the production of high-energy neutrinos. in this study, we focus on one object, 5bzb j0630-2406, which is among the blazars recently proposed as associated with neutrino emission during the first 7 yr of icecube observation... | hadronic processes at work in 5bzb j0630-2406 |
astrometric observations of maser sources in the milky way, using the very long baseline interferometry (vlbi) technique, have been exploited to determine the spiral structure of our galaxy. several major spiral arms have now been pinpointed in the first and second galactic quadrants. fundamental galactic parameters su... | an updated view of the milky way from maser astrometry |
approximately one-third of existing γ-ray sources identified by the fermi gamma-ray space telescope are considered to be unassociated, with no known counterpart at other frequencies/wavelengths. these sources have been the subject of intense scrutiny and observational effort during the observatory's mission lifetime, a... | a combined radio multi-survey catalog of fermi unassociated sources |
cryogenic isolators play an important role in low-noise receiver systems widely employed in millimeter and submillimeter telescopes. to enable a significantly wider intermediate frequency (if) bandwidth, there is strong demand for a wideband, low-loss isolator in modern facilities like the submillimeter array (sma) and... | a low-insertion loss cryogenic edge-mode isolator with 18 ghz bandwidth |
the proposed next generation event horizon telescope (ngeht) concept envisions the imaging of various astronomical sources on scales of microarcseconds in unprecedented detail with at least two orders of magnitude improvement in the image dynamic ranges by extending the event horizon telescope (eht). a key technical co... | millimeter/submillimeter vlbi with a next generation large radio telescope in the atacama desert |
the formation pathways of different types of organic molecules in protostellar envelopes and other regions of star formation are subjects of intense current interest. we present here observations of c4h and ch3oh, tracing two distinct groups of interstellar organic molecules, toward 16 protostars in the ophiuchus and c... | on the origin of c4h and ch3oh in protostellar envelopes |
distributed fx-architecture (difx) is a software very long baseline interferometry (vlbi) correlator currently adopted by several main correlation sites around the globe. after the launch of the radioastron space-vlbi mission in 2011, an extension was necessary to handle processing of an orbiting antenna, to be correla... | the radioastron dedicated difx distribution |
the square kilometre array (ska) is an ambitious project to build the world's largest radio telescope to revolutionize our understanding of the universe and the laws of fundamental physics. geographically distributed between three host countries, and with more than a dozen member nations, the ska is composed of two rad... | highlights of the square kilometre array low frequency (ska-low) telescope |
solar energetic particle (sep) events are commonly separated in two categories: numerous 'impulsive' events of relatively short duration, and a few 'gradual' events, where sep-intensities may stay enhanced over several days at energies up to several tens of mev. in some gradual events the sep spectrum extends to relati... | radio astronomical tools for the study of solar energetic particles ii.time-extended acceleration at subrelativistic and relativistic energies |
modern high-power, large-aperture (hpla) radars have been used in a variety of investigations including the investigation of meteoroid fragmentation. the identification of fragmentation has been based on a detailed interpretation, based on radio science, of head- and trail-echo properties. we now extend the discussion ... | high-altitude meteors and meteoroid fragmentation observed at the jicamarca radio observatory |
radio absorptive materials (rams) are key elements for receivers in the millimeter-wave range. for astronomical applications, cryogenic receivers are widely used to achieve a high-sensitivity. these cryogenic receivers, in particular the receivers for the cosmic microwave background, require that the ram has low surfac... | material survey for a millimeter-wave absorber using a 3d-printed mold |
we present the analysis of multiwavelength observations of seven extragalactic radio sources, listed as unidentified in the third cambridge revised catalog (3cr). x-ray observations, performed during chandra cycle 21, were compared to very large array (vla), wide-field infrared survey explorer, and pan-starrs observati... | hidden treasures in the unknown 3cr extragalactic radio sky: a multiwavelength approach |
high-resolution pure rotational spectra of methoxyacetone and methyl methoxyacetate have been recorded and analyzed by using pulsed jet-expansion fourier transform microwave spectroscopy with the aid of quantum calculations. the global minima for both target molecules have been detected in pulsed jet, whose spectra are... | laboratory measurements and astronomical search for methoxyacetone and methyl methoxyacetate |
astrophysical sources of very high energy (vhe; >100 gev) γ-rays are rare, since gev and tev photons can be only emitted in extreme circumstances involving interactions of relativistic particles with local radiation and magnetic fields. in the context of the fermi large area telescope (lat), only a few sources are k... | the isotropic γ-ray emission above 100 gev: where do very high-energy γ-rays come from? |
we analyze lunar images obtained by the mini radio frequency instrument onboard the lunar reconnaissance orbiter to interpret the anomalous radar scattering observed in some lunar craters. we compare the radar signatures of the crater floors to those of the regions external to the crater rim and show that there is a sy... | modeling radar albedos of laboratory-characterized particles: application to the lunar surface |
interplanetary missions have typically relied on radio science (rs) to recover gravity fields by detecting their signatures on the spacecraft trajectory. the weak gravitational fields of small bodies, coupled with the prominent influence of confounding accelerations, hinder the efficacy of this method. meanwhile, quant... | cold atom interferometry for enhancing the radio science gravity experiment: a phobos case study |
dedispersion, the removal of deleterious smearing of impulsive signals by the interstellar matter, is one of the most intensive processing steps in any radio survey for pulsars and fast transients. we here present a study of the parallelization of this algorithm on many-core accelerators, including gpus from amd and nv... | real-time dedispersion for fast radio transient surveys, using auto tuning on many-core accelerators |
we studied the nearby, interacting galaxy ngc 5195 (m 51b) in the radio, optical and x-ray bands. we mapped the extended, low-surface-brightness features of its radio-continuum emission; determined the energy content of its complex structure of shock-ionized gas; constrained the current activity level of its supermassi... | jets, arcs, and shocks: ngc 5195 at radio wavelengths |
the square kilometre array (ska) will be both the largest radio telescope ever constructed and the largest big data project in the known universe. the first phase of the project will generate on the order of five zettabytes of data per year. a critical task for the ska will be its ability to process data for science, w... | science pipelines for the square kilometre array |
kern is a bi-annually released set of radio astronomical software packages. it should contain most of the standard tools that a radio astronomer needs to work with radio telescope data. the goal of kern is to save time and prevent frustration in setting up of scientific pipelines, and to assist in achieving scientific ... | kern |
in the framework of the gravitational lenses and dark matter (glendama) project, we present a database of nine gravitationally lensed quasars (glqs) that have two or four images brighter than r = 20 mag and are located in the northern hemisphere. this new database consists of a rich variety of follow-up observations in... | new database for a sample of optically bright lensed quasars in the northern hemisphere |
muscat is a large-format mm-wave camera scheduled for installation on the large millimeter telescope alfonso serrano (lmt) in 2018. the muscat focal plane is based on an array of horn-coupled lumped-element kinetic inductance detectors optimized for coupling to the 1.1-mm atmospheric window. the detectors are fed with ... | mexico-uk sub-millimeter camera for astronomy |
context. cu vir has been the first main sequence star that showed regular radio pulses that persist for decades, resembling the radio lighthouse of pulsars and interpreted as auroral radio emission similar to that found in planets. the star belongs to a rare group of magnetic chemically peculiar stars with variable rot... | hst/stis analysis of the first main sequence pulsar cu virginis |
an imaging technique with sensitivity to short duration optical transients is described. the technique is based on the use of wide-field cameras operating in a drift scanning mode, whereby persistent objects produce trails on the sensor and short duration transients occupy localised groups of pixels. a benefit of the t... | high-cadence optical transient searches using drift scan imaging i: proof of concept with a pre-prototype system |
the spectrum of stars in the submillimeter to centimeter wavelength range remains poorly constrained due to a lack of data for most spectral types. an accurate characterization of stellar emission in this regime is needed to test stellar atmosphere models, and is also essential for revealing emission associated with un... | the mesas project: alma observations of the f-type stars γ lep, γ vir a, and γ vir b |
psr j1809-1917 is a young (τ = 51 kyr) and energetic ( $\dot{e}=1.8\times {10}^{36}$ erg s-1) radio pulsar powering an x-ray pulsar wind nebula (pwn) that exhibits morphological variability. we report on the results of a new monitoring campaign by the chandra x-ray observatory (chandra), carried out across six epochs w... | chandra monitoring of the j1809-1917 pulsar wind nebula and its field |
we investigate whether varying the dust composition (described by the optical constants) can solve a persistent problem in debris disk modeling—the inability to fit the thermal emission without overpredicting the scattered light. we model five images of the β pictoris disk: two in scattered light from the hubble space ... | a comprehensive dust model applied to the resolved beta pictoris debris disk from optical to radio wavelengths |
nearly everything we know about extrasolar planets to date comes from optical astronomy. while exoplanetary aurorae are predicted to be bright at low radio frequencies (<1 ghz), we consider the effect of an exoplanet transit on radio emission from the host star. as radio emission from solar-like stars is concentrate... | exoplanet transits with next-generation radio telescopes |
we present the results of commissioning observations for a new digital beam-forming back end for the focal plane l-band array for the robert c. byrd green bank telescope (flag), a cryogenically cooled phased array feed (paf) with the lowest measured tsys/η of any paf outfitted on a radio telescope to date. we describe ... | commissioning the h i observing mode of the beam former for the cryogenically cooled focal l-band array for the gbt (flag) |
context. the nkakc = 404-313 transitions of ortho-ch2 between 68 and 71 ghz were first detected toward the orion-kl and w51 main star-forming regions. given their high upper level energies (225 k) above the ground state, they were naturally thought to arise in dense, hot molecular cores near newly formed stars. however... | hunting for the elusive methylene radical |
context. the envelopes of molecular gas around embedded low-mass protostars show different chemistries, which can be used to trace their formation history and physical conditions. the excitation conditions of some molecular species can also be used to trace these physical conditions, making it possible to constrain for... | probing the effects of external irradiation on low-mass protostars through unbiased line surveys |
radio astronomy has traditionally depended on observatories allocating time to observers for exclusive use of their telescopes. the disadvantage of this scheme is that the data thus collected is rarely used for other astronomy applications, and in many cases, is unsuitable. for example, properly calibrated pulsar searc... | setiburst: a robotic, commensal, realtime multi-science backend for the arecibo telescope |
we report the discovery and follow-up observations of vt 1137-0337, an unusual radio transient found in our systematic search for extragalactic explosions in the very large array sky survey. it is located in the brightest region of a dwarf starburst galaxy at a luminosity distance of 121.6 mpc. its 3 ghz luminosity is ... | a flat-spectrum radio transient at 122 mpc consistent with an emerging pulsar wind nebula |
a powerful new radio telescope will improve our understanding of galaxy formation and evolution, and other key questions in astrophysics, says fernando camilo, on behalf of the meerkat team. | african star joins the radio astronomy firmament |
the radio-quiet quasar q2059-360 at redshift z = 3.08 is known to be close to a small lyman α blob (lab) and to be absorbed by a proximate damped lyα (pdla) system. here, we present the multi unit spectroscopic explorer (muse) integral field spectroscopy follow-up of this quasi-stellar object (qso). our primary goal is... | muse-inspired view of the quasar q2059-360, its lyman α blob, and its neighborhood |
context. thioformamide nh2chs is a sulfur-bearing analog of formamide nh2cho. the latter was detected in the interstellar medium back in the 1970s. most of the sulfur-containing molecules detected in the interstellar medium are analogs of corresponding oxygen-containing compounds. therefore, thioformamide is an interes... | millimeter- and submillimeter-wave spectroscopy of thioformamide and interstellar search toward sgr b2(n) |
we present a detailed single-pulse analysis for psr b1929+10 based on observations with the five-hundred-meter aperture spherical radio telescope (fast). the main pulse (mp) and interpulse (ip) are found to be modulated with a periodicity of ∼12 times the pulsar's rotational period (p). the ∼12p modulation is confirmed... | periodic and phase-locked modulation in psr b1929+10 observed with fast |
we use a chandra x-ray observation of the gravitationally lensed system mg b2016+112 at z = 3.273 to elucidate the presence of at least two x-ray sources. we find that these sources are consistent with the very long baseline interferometry (vlbi) components measured by spingola, which are separated by ~200 pc. their in... | resolving complex inner x-ray structure of the gravitationally lensed agn mg b2016+112 |
we compare the co(1-0) and hα kinematics in 34 nearby galaxies, selected from the almaquest and edge-califa surveys. we use 3d-barolo, a 3d tilted-ring model, to derive the co and hα rotation curves. before comparing rotation curves in the 34 nearby galaxies, we found systematics between the manga and califa data using... | the almaquest survey. viii. what causes the discrepancy in the velocity between the co and hα rotation curves in galaxies? |
intensity interferometry originates from the field of radio astronomy on the trace of robert hanbury brown and richard quincy twiss. in high energy physics, the phenomena was discovered by goldhaber, goldhaber, lee and pais. in radio astronomy the method is exceeded by more modern approaches but in high energy physics,... | probing the qcd phase diagram with hbt femtoscopy |
we report the properties of molecular gas in a sample of six host galaxies of fast radio bursts (frbs) obtained from co observations with the atacama large millimeter/submillimeter array (frbs 20180924b, 20190102c, and 20190711a), the results of one nondetection in a dwarf galaxy (frb 20121102a), and two events detecte... | diverse properties of molecular gas in the host galaxies of fast radio bursts |
for accurate astronomic and geodetic observations based on radio telescopes, the elevation-dependent deformation of the radio telescopes' main reflectors should be known. terrestrial laser scanning has been used for determining the corresponding changes of focal lengths and areal reflector deformations at several occas... | terrestrial laser scanner two-face measurements for analyzing the elevation-dependent deformation of the onsala space observatory 20-m radio telescope's main reflector in a bundle adjustment |
to master the electromagnetic environment characteristics around the five-hundred-meter aperture spherical radio telescope (fast) and ensure a better ecological environment in the radio-quiet zone of fast, we analyzed the radiation characteristics of the public communication stations around fast. by comparing the fast ... | the electromagnetic compatibility between fast and public mobile communication stations and its cognitive using frequency strategy |
we report on a 275-500 ghz heterodyne receiver system in combination with a wideband intermediate-frequency (if) backend to realize 17 ghz instantaneous bandwidth. the receiver frontend implements a heterodyne mixer module that integrates a superconductor-insulator-superconductor (sis) mixer chip and a cryogenic low-no... | demonstration of a wideband submillimeter-wave low-noise receiver with 4-21 ghz if output digitized by a high-speed 32 gsps adc |
context. all but one complex organic molecule (com) detected so far in the interstellar medium (ism) are achiral; propylene oxide (c-c2h3o)-ch3 is the only exception to this. finding other chiral species is a priority for astrobiology to progress in the understanding of the emergence of life. whatever the conditions of... | the quest of chirality in the interstellar medium. i. lessons of propylene oxide detection |
radio bursts from the solar corona can provide clues to forecast space-weather hazards. after recent technology advancements, regular monitoring of radio bursts has increased and large observational datasets are produced. hence, manual identification and classification of them is a challenging task. in this article, we... | automated detection of solar radio bursts using a statistical method |
automated classification of astronomical sources is often challenging due to the scarcity of labelled training data. we present a data set with a total number of 2158 data items that contains radio galaxy images with their corresponding morphological labels taken from various catalogues [1,2]. the data set is curated b... | first radio galaxy data set containing curated labels of classes fri, frii, compact and bent |
the observational facilities of radio astronomy keep constant upgrades and developments to achieve better capabilities including increasing the time of the data recording and frequency resolutions, and increasing the receiving and recording bandwidth. however in contrast, only a limited spectrum resource has been alloc... | radio frequency interference mitigation |
we present two methods for measuring the noise temperature of a differential input single-ended output (diso) low-noise amplifier (lna) connected to an antenna. the first method is direct measurement of the diso lna and antenna in an anechoic chamber at ambient temperature. the second is a simple and low-cost noise par... | cold-source noise measurement of a differential input single-ended output low-noise amplifier connected to a low-frequency radio astronomy antenna |
a new 1.4 ghz, 19-element, dual-polarization, cryogenic phased-array feed (paf) radio astronomy receiver has been developed for the robert c. byrd green bank telescope (gbt) as part of the focal l-band array for the gbt (flag) project. commissioning observations of calibrator radio sources show that this receiver has t... | performance of a highly sensitive, 19-element, dual-polarization, cryogenic l-band phased-array feed on the green bank telescope |
collisions between galaxy clusters provide a unique opportunity to study matter in a parameter space which cannot be explored in our laboratories on earth. in the standard λcdm model, where the total density is dominated by the cosmological constant (λ) and the matter density by cold dark matter (cdm), structure format... | cluster physics with merging galaxy clusters |
chandra x-ray observations are analyzed for five galaxy clusters whose atmospheric cooling times, entropy parameters, and ratios of cooling time to freefall time within the central galaxies lie below 1 gyr, below 30 kev cm2, and between 20 ≲ min(tcool/tff) ≲ 50, respectively. these thermodynamic properties are commonly... | thermally unstable cooling stimulated by uplift: the spoiler clusters |
rf system-on-chip (rfsoc) devices provide the potential for implementing a complete radio astronomy receiver on a single board, but performance of the integrated analogue-to-digital converters (adcs) is critical. we have evaluated the performance of the data converters in the xilinx zu28dr rfsoc, which are 12-bit, 8-fo... | characterizing the performance of high-speed data converters for rfsoc-based radio astronomy receivers |
we developed a gpu based single-pulse search pipeline (gsp) with a candidate-archiving database. largely based upon the infrastructure of the open source pulsar exploration and search toolkit (presto), gsp implements gpu acceleration of the de-dispersion and integrates a candidate-archiving database. we applied gsp to ... | a gpu based single-pulse search pipeline (gsp) with database and its application to the commensal radio astronomy fast survey (crafts) |
the integral hard x-ray surveys have proven to be of fundamental importance. integral has mapped the galactic plane with its large field of view and excellent sensitivity. such hard x-ray snapshots of the whole milky way on a time scale of a year are beyond the capabilities of past and current narrow-fov grazing incide... | 15 years of galactic surveys and hard x-ray background measurements |
context. we have performed a spectral line survey called exploring molecular complexity with alma (emoca) toward sagittarius b2(n) between 84.1 and 114.4 ghz with the atacama large millimeter/submillimeter array (alma) in its cycles 0 and 1. line intensities of the main isotopic species of ethyl cyanide and its singly ... | spectroscopic study and astronomical detection of doubly 13c-substituted ethyl cyanide |
the new wide-field radio telescopes, such as: askap, mwa, lofar, evla and ska; will produce spectral-imaging data-cubes (sidc) of unprecedented size-in the order of hundreds of petabytes. servicing such data as images to the end-user in a traditional manner and formats is likely going to encounter significant performan... | astronomical imagery: considerations for a contemporary approach with jpeg2000 |
upcoming h i surveys will deliver large datasets, and automated processing using the full 3-d information (two positional dimensions and one spectral dimension) to find and characterize h i objects is imperative. in this context, visualization is an essential tool for enabling qualitative and quantitative human control... | the role of 3-d interactive visualization in blind surveys of h i in galaxies |
we present a new approach to multifrequency synthesis in radio astronomy. using bayesian inference techniques, the new technique estimates the sky brightness and the spectral index simultaneously. in principle, the bandwidth of a wide-band observation can be fully exploited for sensitivity and resolution, currently onl... | a new approach to multifrequency synthesis in radio interferometry |
the field of radio astronomy is witnessing a boom in the amount of data produced per day due to newly commissioned radio telescopes. one of the most crucial problems in this field is the automatic classification of extragalactic radio sources based on their morphologies. most recent contributions in the field of morpho... | morphological classification of extragalactic radio sources using gradient boosting methods |
we demonstrate a radio-frequency parametric amplifier that exploits the gate-tunable quantum capacitance of an ultra high mobility two dimensional electron gas (2deg) in a gaas heterostructure at cryogenic temperatures. the prototype narrowband amplifier exhibits a gain greater than 20 db up to an input power of - 66 d... | an rf quantum capacitance parametric amplifier |
clusters of galaxies are outstanding laboratories for understanding the physics of supermassive black hole (smbh) feedback. here we present the first chandra, karl g. jansky very large array, and hubble space telescope analysis of macs j1447.4+0827 (z = 0.3755), one of the strongest cool core clusters known, in which e... | a multiwavelength study of the cool core cluster macs j1447.4+0827 |
we have extended our previous work to use the murchison widefield array (mwa) as a non-coherent passive radar system in the fm frequency band, using terrestrial fm transmitters to illuminate objects in low earth orbit (leo) and the mwa as the sensitive receiving element for the radar return. we have implemented a blind... | a low-frequency blind survey of the low earth orbit environment using non-coherent passive radar with the murchison widefield array |
non-perturbative quantum gravity prevents the formation of curvature singularities and may allow black holes to decay with a lifetime shorter than evaporation time. this, in connection with the existence of primordial black holes, could open a new window for quantum-gravity phenomenology. i discuss the possibility of o... | measuring the last burst of non-singular black holes |
modern interferometric imaging relies on advanced calibration that incorporates direction-dependent effects. their increasing number of antennas (e.g. in lofar, vla, meerkat/ ska) and sensitivity are often tempered with the accuracy of their calibration. beam accuracy drives particularly the capability for high dynamic... | primary beam effects of radio astronomy antennas - i. modelling the karl g. jansky very large array (vla) l-band beam using holography |
a large number of observations from the parkes 64 m diameter radio telescope, recorded with high time resolution, are publicly available. we have reprocessed all of the observations obtained during the first four years (from 1997-2001) of the parkes multibeam receiver system in order to identify transient events, and h... | parkes transient events. i. database of single pulses, initial results, and missing fast radio bursts |
radio frequency interference (rfi) will pollute the weak astronomical signals receivedby radio telescopes, which in return will seriously affect the time-domain astronomical observation and research. in this paper, we use a deep learning method to identify rfi in frequency spectrum data, and propose a neural network ba... | dsc based dual-resunet for radio frequency interference identification |
understanding dark matter is one of the most urgent questions in modern physics. a very interesting candidate is primordial black holes (pbhs). for the mass ranges <10-16m ⊙ and >100 m ⊙, pbhs have been ruled out. however, they are still poorly constrained in the mass range 10-16-100 m ⊙. fast radio bursts (frbs)... | future constraints on dark matter with gravitationally lensed fast radio bursts detected by burstt |
at the time of defining the science objectives of the international gamma-ray astrophysics laboratory (integral), such a rapid and spectacular development of multi-messenger astronomy could not have been predicted, with new impulsive phenomena becoming accessible through different channels. neutrino telescopes have rou... | multi-messenger astronomy with integral |
monitoring observations of solar microwave fluxes and their polarization began in japan during the 1950s at toyokawa and mitaka. at present (april 2022), monitoring observations continues with the nobeyama radio polarimeters (norp) at the nobeyama campus of the national astronomical observatory of japan (naoj). in this... | over seven decades of solar microwave data obtained with toyokawa and nobeyama radio polarimeters |
frequency channelization is a fundamental signal processing operation employed across various domains, including communications and radio astronomy. the polyphase filterbank (pfb) represents an efficient and versatile means of channelization. when strict constraints are placed on the allowable spectral leakage between ... | performance of oversampled polyphase filterbank inversion via fourier transform |
our previously reported survey of the low earth orbit (leo) environment using the murchison widefield array (mwa) detected over 70 unique resident space objects (rsos) over multiple passes, from 20 h of observations in passive radar mode. in this paper, we extend this work by demonstrating two methods that improve the ... | improved sensitivity for space domain awareness observations with the murchison widefield array |
we present our third set of results from our mid-infrared imaging survey of milky way giant h ii regions with our detailed analysis of w49a, one of the most distant, yet most luminous, gh ii regions in the galaxy. we used the forcast instrument on the stratospheric observatory for infrared astronomy (sofia) to obtain 2... | surveying the giant h ii regions of the milky way with sofia. iii. w49a |
this paper presents a built-in calibration procedure of a 10-to-20 ghz polarimeter aimed at measuring the i, q, u stokes parameters of cosmic microwave background (cmb) radiation. a full-band square waveguide double directional coupler, mounted in the antenna-feed system, is used to inject differently polarized referen... | calibration of a polarimetric microwave radiometer using a double directional coupler |
the doppler effect has well-established applications in astronomy, medicine, radar and metrology. recently, a number of experimental demonstrations of the inverse doppler effect have begun to appear. however, the inverse doppler effect has never been observed on an electronically reconfigurable system with an external ... | realizing tunable inverse and normal doppler shifts in reconfigurable rf metamaterials |
unlike blazars, radio galaxies have jets that are misaligned relative to our line-of-sight. this misaligned geometry provides us with a unique view of both the jet and super massive black hole. to date, four radio galaxies have been detected at tev energies with an additional two active galactic nuclei shown to exhibit... | radio galaxies at tev energies |
context. deuterated forms of ch are thought to be responsible for deuterium enrichment in lukewarm astronomical environments. there is no unambiguous detection of ch2d+ in space to date.aims: four submillimetre rotational lines of ch2d+ are documented in the literature. our aim is to present a complete dataset of highl... | double resonance rotational spectroscopy of ch2d+ |
we report on an exploratory project aimed at performing immersive 3d visualization of astronomical data, starting with spectral-line radio data cubes from galaxies. this work is done as a collaboration between the department of physics and astronomy and the department of computer science at the university of manitoba. ... | 3d visualization of astronomy data cubes using immersive displays |
the sensitivity of a single station is a crucial performance characteristic of the low-frequency component of the square kilometre array (ska-low). in this contribution, the sensitivity of a prototype station of the ska-low, the aperture array verification system version 2 (aavs2), measured at frequencies 70.3, 110.2, ... | preliminary sensitivity verification of the ska-low aavs2 prototype |
the next generation very large array (ngvla) will be the premiere centimeter-wave radio array in the northern hemisphere by the mid 2030s and thus has the potential to be one of the most effective instruments for the search for extraterrestrial intelligence (seti). we show that, as of now, the ngvla will be the only fa... | search for extraterrestrial intelligence with the ngvla |
cosmic neutrinos are expected to include a significant flux of tau neutrinos due to flavor mixing over astronomical length scales. however, the tau-neutrino content of astrophysical neutrinos is poorly constrained and a significant flux of cosmogenic tau neutrinos awaits discovery. earth-skimming tau neutrinos undergo ... | a new concept for high-elevation radio detection of tau neutrinos |
transient radio-frequency interference (rfi) events can be generated as unintended by-products of the normal operation of devices such as mechanical relays or electric motors. in the radio astronomy reserve in south africa, several new radio telescopes such as meerkat, the square kilometre array, and the hydrogen epoch... | characterizing transient radio-frequency interference |
high-energy neutrino astronomy will probe the working of the most violent phenomena in the universe. the giant radio array for neutrino detection (grand) project consists of an array of ∼ 105 radio antennas deployed over ∼ 200 000 km2 in a mountainous site. it aims at detecting high-energy neutrinos via the measurement... | the giant radio array for neutrino detection |
models of the upper transition region of sunspots have been derived based on the observed radio spectrum between 3 and 18 ghz from radio astronomical telescope of the academy of sciences 600 (ratan-600) observations. our objective is to match the spectrum to show that, within the limits of the one-dimensional observati... | modeling of solar atmosphere parameters above sunspots using ratan-600 microwave observations |
we present a proof of concept on the coupling of radio astronomical receivers and spectrometers with chemical reactors and the performances of the resulting setup for spectroscopy and chemical simulations in laboratory astrophysics. several experiments including cold plasma generation and uv photochemistry were perform... | using radio astronomical receivers for molecular spectroscopic characterization in astrochemical laboratory simulations: a proof of concept |
this paper studies how to employ synchrotron emission gradient techniques to reveal the properties of the magnetic field within the interstellar media. based on data cubes of three-dimensional numerical simulations of magnetohydrodynamic turbulence, we explore spatial gradients of synchrotron emission diagnostics to tr... | tracing magnetic fields by the synergies of synchrotron emission gradients |
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