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the smith cloud (sc) is a gaseous high-velocity cloud (hvc) in an advanced state of accretion, only 2.9 kpc below the galactic plane and due to impact the disk in ≈27 myr. it is unique among hvcs in having a known distance (12.4 ± 1.3 kpc) and a well-constrained 3d velocity (296 km s-1), but its origin has long remaine... | on the metallicity and origin of the smith high-velocity cloud |
we review the results of hi line surveys of extragalactic sources in the local universe. in the last two decades major efforts have been made in establishing on firm statistical grounds the properties of the hi source population, the two most prominent being the hi parkes all sky survey and the arecibo legacy fast alfa... | extragalactic hi surveys |
context. it has become evident that one-zone synchrotron self-compton models are not always adequate for very high-energy (vhe) gamma-ray-emitting blazars. while two-component models perform better, they are difficult to constrain due to the large number of free parameters.aims: in this work, we make a first attempt at... | testing two-component models on very high-energy gamma-ray-emitting bl lac objects |
the murchison widefield array is a square kilometre array precursor. the telescope is located at the murchison radio-astronomy observatory in western australia. the mwa consists of 4 096 dipoles arranged into 128 dual polarisation aperture arrays forming a connected element interferometer that cross-correlates signals ... | the murchison widefield array correlator |
real-time tracking of a waveform frequency content is essential for detection and analysis of fast rare events in communications, radar, radio astronomy, spectroscopy, sensing etc. this requires a method that can provide real-time spectrum analysis (rt-sa) of high-speed waveforms in a continuous and gap-free fashion. d... | real-time gap-free dynamic waveform spectral analysis with nanosecond resolutions through analog signal processing |
maximum entropy is an image reconstruction method conceived to image a sparsely occupied field of view, therefore it is particularly effective at achieving super-resolution effects. although widely used in image deconvolution, this method has been formulated in radio astronomy for the analysis of observations in the sp... | mem_ge: a new maximum entropy method for image reconstruction from solar x-ray visibilities |
the next generation very large array (ngvla) is a planned radio interferometer providing unprecedented sensitivity at wavelengths between 21 cm and 3 mm. its 263 antenna element array will be spatially distributed across north america to enable both superb low surface brightness recovery and sub-milliarcsecond angular ... | a collection of german science interests in the next generation very large array |
the angular distribution of the cosmic microwave background radiation (cmbr) in the sky shows a dipole asymmetry, ascribed to the peculiar velocity of the observer (or rather of the solar system), where peculiar velocity is defined as motion relative to the local comoving coordinates. the peculiar velocity thus determi... | large disparity in cosmic reference frames determined from the sky distributions of radio sources and the microwave background radiation |
this work presents the initial results of the drift-scan observation for the neutral hydrogen (hi) intensity mapping survey with the five-hundred-meter aperture spherical radio telescope (fast). the data analyzed in this work were collected in night observations from 2019 through 2021. the primary findings are based on... | fast drift scan survey for hi intensity mapping: i. preliminary data analysis |
we report on the discovery of a mysterious ultra-steep-spectrum (uss) synchrotron source in the galaxy cluster a2877. we have observed the source with the murchison widefield array at five frequencies across 72-231 mhz and found the source to exhibit strong spectral curvature over this range, as well as the steepest kn... | ultra-steep-spectrum radio "jellyfish" uncovered in a2877 |
we present a catalog of the millimeter-wave (mm-wave) continuum properties of 98 nearby (z < 0.05) active galactic nuclei (agns) selected from the 70 month swift/bat hard-x-ray catalog that have precisely determined x-ray spectral properties and subarcsecond-resolution atacama large millimeter/submillimeter array ba... | bass. xxxiv. a catalog of the nuclear millimeter-wave continuum emission properties of agns constrained on scales ≤ 100-200 pc |
we present the discovery of the first millimeter afterglow of a short-duration γ-ray burst (sgrb) and the first confirmed afterglow of an sgrb localized by the guano system on swift. our atacama large millimeter/sub-millimeter array (alma) detection of sgrb 211106a establishes an origin in a faint host galaxy detected ... | the first short grb millimeter afterglow: the wide-angled jet of the extremely energetic sgrb 211106a |
the square kilometre array observatory (skao) will explore the radio sky to new depths in order to conduct transformational science. skao data products made available to astronomers will be correspondingly large and complex, requiring the application of advanced analysis techniques to extract key science findings. to t... | ska science data challenge 2: analysis and results |
many astronomical phenomena, including fast radio bursts and soft gamma repeaters, consist of brief distinct aperiodic events. the intervals between these events vary randomly, but there are periods of greater activity, with shorter mean intervals, and of lesser activity, with longer mean intervals. a single dimensionl... | log-normal waiting time widths characterize dynamics |
this whitepaper focuses on the astrophysical systematics which are encountered in dark matter searches. oftentimes in indirect and also in direct dark matter searches, astrophysical systematics are a major limiting factor to sensitivity to dark matter. just as there are many forms of dark matter searches, there are man... | snowmass2021 cosmic frontier: synergies between dark matter searches and multiwavelength/multimessenger astrophysics |
young supernova remnants strongly modify the surrounding magnetic fields, which in turn play an essential role in accelerating cosmic rays (crs). the x-ray polarization measurements probe magnetic field morphology and turbulence at the immediate acceleration site. we report the x-ray polarization distribution in the no... | magnetic structures and turbulence in sn 1006 revealed with imaging x-ray polarimetry |
accretion of material onto a black hole drags any magnetic fields present inwards, increasing their strength. theory predicts that sufficiently strong magnetic fields can halt the accretion flow, producing a magnetically arrested disk (mad). we analyzed archival multiwavelength observations of an outburst from the blac... | observations of a black hole x-ray binary indicate formation of a magnetically arrested disk |
we present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the southern argentina agile meteor radar (saamer) orbital system (os), in which over three-quarters of a million orbits of dust particles were determined from 2012 january through 2015 april. saamer-os is locat... | the southern argentina agile meteor radar orbital system (saamer-os): an initial sporadic meteoroid orbital survey in the southern sky |
changes in the sky noise spectrum are used to characterize perturbations in the ionosphere. observations were made at the same sidereal time on multiple days using a calibrated broadband dipole and radio spectrometer covering 80 to 185 mhz. in this frequency range, an ionospheric opacity perturbation changes both the e... | radiometric measurements of electron temperature and opacity of ionospheric perturbations |
gamma-ray bursts (grbs) are extra-galactic and extremely energetic transient emissions of gamma rays, which are thought to be associated with the death of massive stars or the merger of compact objects in binary systems. their huge luminosities involve the presence of a newborn stellar-mass black hole emitting a relati... | gamma-ray bursts at high and very high energies |
we present continuum observations at λ = 1.3 and 2.7 mm using the combined array for research in millimeter-wave astronomy toward six protoplanetary disks in the taurus molecular cloud: ci tau, dl tau, do tau, ft tau, haro 6-13, and hl tau. we constrain physical properties of the disks with bayesian inference using two... | resolving protoplanetary disks at millimeter wavelengths with carma |
we report the results of high-resolution molecular line observations of the high-velocity compact cloud hcn-0.085-0.094 with the atacama large millimeter/submillimeter array. the hcn j = 4-3, hco+ j = 4-3, and cs j = 7-6 line images reveal that hcn-0.085-0.094 consists mainly of three small clumps with extremely broad ... | the fifth candidate for an intermediate-mass black hole in the galactic center |
we have carried out a chandra x-ray and multifrequency radio very long baseline array study of the active galactic nucleus (agn) txs 0128+554, which is associated with the fermi γ-ray source 4fgl j0131.2+5547. the agn is unresolved in a target 19.3 ks chandra image, and its spectrum is well fit by a simple absorbed pow... | txs 0128+554: a young gamma-ray-emitting active galactic nucleus with episodic jet activity |
angular momentum is one of the most important physical quantities that governs star formation. the initial angular momentum of a core may be responsible for its fragmentation, and can have an influence on the size of the protoplanetary disk. to understand how cores obtain their initial angular momentum, it is important... | rotating filament in orion b: do cores inherit their angular momentum from their parent filament? |
we present deep (265 ks) chandra x-ray observations of pso j352.4034-15.3373, a quasar at z = 5.831 that, with a radio-to-optical flux ratio of r > 1000, is one of the radio-loudest quasars in the early universe and is the only quasar with observed extended radio jets of kiloparsec scale at z ≳ 6. modeling the x-ray... | enhanced x-ray emission from the most radio-powerful quasar in the universe's first billion years |
we present alma cycle-0 observations of the co (6-5) line emission and of the 435 μm dust continuum emission in the central kiloparsec of ngc 1614, a local luminous infrared galaxy at a distance of 67.8 mpc (1{\prime \prime }= 329 pc). the co emission is well resolved by the alma beam (0.''26 × 0.''20) into a circumnuc... | alma observations of warm dense gas in ngc 1614—breaking of the star formation law in the central kiloparsec |
context. recent years have been seeing huge developments of radio telescopes and a tremendous increase in their capabilities (sensitivity, angular and spectral resolution, field of view, etc.). such systems make designing more sophisticated techniques mandatory not only for transporting, storing, and processing this ne... | moresane: model reconstruction by synthesis-analysis estimators. a sparse deconvolution algorithm for radio interferometric imaging |
context. ammonia and its deuterated isotopologues probe physical conditions in dense molecular cloud cores. the time-dependence of deuterium fractionation and the relative abundances of different nuclear spin modifications are supposed to provide a means of determining the evolutionary stages of these objects.aims: we ... | deuteration of ammonia in the starless core ophiuchus/h-mm1 |
we use measurements from the experiment to detect the global eor signature (edges) to determine scale and zero-level corrections to the diffuse radio surveys by guzmán et al. at 45 mhz and by landecker & wielebinski at 150 mhz. we find that the map of guzmán et al. requires a scale correction of 1.076 ± 0.034 (2σ) ... | absolute calibration of diffuse radio surveys at 45 and 150 mhz |
a tidal disruption event (tde) involves the shredding of a star in the proximity of a supermassive black hole (smbh). the nearby (≈230 mpc) relatively radio-quiet, thermal-emission-dominated source at2019dsg is the first tde with a potential neutrino association. the origin of nonthermal emission remains inconclusive; ... | high-resolution vlbi observations of and modeling the radio emission from the tidal disruption event at2019dsg |
inference is crucial in modern astronomical research, where hidden astrophysical features and patterns are often estimated from indirect and noisy measurements. inferring the posterior of hidden features, conditioned on the observed measurements, is essential for understanding the uncertainty of results and downstream ... | α-deep probabilistic inference (α-dpi): efficient uncertainty quantification from exoplanet astrometry to black hole feature extraction |
we describe the first-season co mapping array project (comap) analysis pipeline that converts raw detector readouts to calibrated sky maps. this pipeline implements four main steps: gain calibration, filtering, data selection, and mapmaking. absolute gain calibration relies on a combination of instrumental and astrophy... | comap early science. iii. co data processing |
context. the interaction of expanding h ii regions with their environmental clouds is one of the central questions driving the stratospheric observatory for infrared astronomy (sofia) legacy program feedback.aims: we want to understand the interaction of the prototypical ngc 7538 h ii region with the neighboring molecu... | feedback from the ngc 7538 h ii region |
this paper presents the esa voyage 2050 white paper for a concept of terahertz exploration and zooming-in for astrophysics (theza). it addresses the science case and some implementation issues of a space-borne radio interferometric system for ultra-sharp imaging of celestial radio sources at the level of angular resolu... | theza: terahertz exploration and zooming-in for astrophysics |
sixth-generation wireless networks will aggregate higher-than-ever mobile traffic into ultra-high capacity backhaul links, which could be deployed on the largely untapped spectrum above 100 ghz. current regulations however prevent the allocation of large contiguous bands for communications at these frequencies, since s... | dynamic spectrum sharing between active and passive users above 100 ghz |
the cyclopropenylidenyl carbene, c-(c)c3h2, should make for an excellent probe of unidentified infrared bands. it has a dipole moment of roughly 5.0 d making it easily detectable rotationally from the ground. furthermore, it has vibrational frequencies computed here with proven and high-level quantum chemical methods t... | a small molecule with pah vibrational properties and a detectable rotational spectrum: c-(c)c3h2, cyclopropenylidenyl carbene |
in the current era of radio astronomy, continuum surveys observe a multitude of objects with complex morphologies and sizes, and are not limited to observing point sources. typical radio source extraction software generates catalogues by using gaussian components to form a model of the emission. this may not be well su... | radio source extraction with profound |
in the spirit of effective field theory, the standard-model extension (sme) provides a comprehensive framework to systematically probe the possibility of lorentz/c p t violation. in the pure gravity sector, operators with mass dimension larger than 4, while in general being advantageous to short-range experiments, are ... | testing velocity-dependent c p t -violating gravitational forces with radio pulsars |
fast radio bursts (frbs) are a class of highly energetic, mostly extragalactic radio transients lasting for ~milliseconds. while over 600 frbs have been published so far, their origins are presently unclear, with some theories for extragalactic frbs predicting accompanying high-energy emission. in this work, we use the... | limits on fast radio burst-like counterparts to gamma-ray bursts using chime/frb |
the first data release from apertif survey contains 3074 radio continuum images, covering a thousand square degrees of the sky. the observations were performed between august 2019 and july 2020. the continuum images were produced at a central frequency 1355 mhz, with a bandwidth of ~150 mhz and angular resolution of up... | continuum source catalog for the first apertif data release |
radio relics are patches of diffuse synchrotron radio emission that trace shock waves. relics are thought to form when intracluster medium electrons are accelerated by cluster merger-induced shock waves through the diffusive shock acceleration mechanism. in this paper, we present observations spanning 150 mhz to 30 ghz... | the widest frequency radio relic spectra: observations from 150 mhz to 30 ghz |
we review the development of multi-pixel heterodyne receivers for astronomical research in the submillimeter and terahertz spectral domains. we shortly address the historical development, highlighting a few pioneering instruments. a discussion of the design concepts is followed by a presentation of the technologies emp... | terahertz heterodyne array receivers for astronomy |
we review the current state-of-affairs in radio observations of coronal mass ejections (cmes) from a space weather perspective. in particular, we examine the role of radio observations in predicting or presaging an eruption, in capturing the formation stages of the cme, and in following the cme evolution in the corona ... | radio observations of coronal mass ejections: space weather aspects |
astronomy is moving into the era of "big data", a paradigm where data volumes will be reaching 10s of pbs (askap), and in the near future 100s of pbs (ska1). science from the next generation of radio telescopes requires long term storage of the data and tools for querying and accessing the data. at csiro we have addres... | the csiro askap science data archive |
the enigmatic class of fanaroff-riley type 0 (fr0) radio galaxies is emerging as the missing link between the faint yet numerous population of compact radio sources in nearby galaxies and the canonical fanaroff-riley classification scheme. this letter reports the first γ-ray identification of three fr0 galaxies above 1... | a new gamma-ray-emitting population of fr0 radio galaxies |
we present two searches for icecube neutrino events coincident with 28 fast radio bursts (frbs) and 1 repeating frb. the first improves on a previous icecube analysis—searching for spatial and temporal correlation of events with frbs at energies greater than roughly 50 gev—by increasing the effective area by an order o... | a search for mev to tev neutrinos from fast radio bursts with icecube |
we performed a long-term optical (b, v, r bands), infrared (j and k bands), and radio band (15, 22, 37 ghz band) study of the flat spectrum radio quasar, 3c 454.3, using data collected over a period of more than 8 yr (mjd 54500-57500). the temporal variability, spectral properties, and interwaveband correlations were s... | long-term variability and correlation study of the blazar 3c 454.3 in the radio, nir, and optical wavebands |
we apply a machine learning technique known as convolutional denoising autoencoder to denoise synthetic images of state-of-the-art radio telescopes, with the goal of detecting the faint, diffused radio sources predicted to characterize the radio cosmic web. in our application, denoising is intended to address both the ... | convolutional deep denoising autoencoders for radio astronomical images |
the commensal radio astronomy five-hundred-meter aperture spherical radio telescope (fast) survey (crafts) utilizes the novel drift-scan commensal survey mode of fast and can generate billions of pulsar candidate signals. the human experts are not likely to thoroughly examine these signals, and various machine sorting ... | pulsar candidate selection using ensemble networks for fast drift-scan survey |
massive star-forming regions with observed infall motions are good sites for studying the birth of massive stars. in this paper, 405 compact sources have been extracted from the apex telescope large area survey of the galaxy (atlasgal) compact sources that also have been observed in the millimetre astronomy legacy team... | infall motions in massive star-forming regions: results from years 1 and 2 of the malt90 survey |
we present a revised table of 390 galactic radio supernova remnants (snrs) and their basic parameters. statistical analyses are performed on snr diameters, ages, spectral indices, galactic heights, and spherical symmetries. furthermore, the accuracy of distances estimated using the σ-d relation is examined. the arithme... | a statistical analysis of galactic radio supernova remnants |
the radio sky at frequencies below ~10 mhz is still largely unknown; this remains the last unexplored part of the electromagnetic spectrum in astronomy. the upcoming space experiments aiming at such low frequencies (ultralong wavelengths or ultralow frequencies) would benefit from reasonable expectations of the sky bri... | an ultralong-wavelength sky model with absorption effect |
blazars are a remarkable type of active galactic nuclei (agn) that are playing an important and rapidly growing role in today's multi-frequency and multi-messenger astrophysics. in the past several years, blazars have been discovered in relatively large numbers in radio, microwave, x-ray and gamma-ray surveys, and more... | the open universe vou-blazars tool |
we present a spatio-kinematical analysis of the co (j = 2 → 1) line emission, observed with the atacama large millimeter/submillimeter array (alma), of the outflow associated with the most massive core, alma1, in the 70 μm dark clump g010.991-00.082. the position-velocity (pv) diagram of the molecular outflow exhibits ... | the alma survey of 70 μm dark high-mass clumps in early stages (ashes). iii. a young molecular outflow driven by a decelerating jet |
the current paradigm of star formation through accretion disks, and magnetohydrodynamically driven gas ejections, predicts the development of collimated outflows, rather than expansion without any preferential direction. we present radio continuum observations of the massive protostar w75n(b)-vla 2, showing that it is ... | observing the onset of outflow collimation in a massive protostar |
the double plasma resonance (dpr) effect is the phenomenon of a sharply increased instability of plasma waves in a magnetized plasma when the upper hybrid frequency coincides with the cyclotron harmonic frequency. a radiation mechanism associated with this effect provides an explanation for the origin of the ‘zebra pat... | double plasma resonance and its manifestations in radio astronomy |
we present the hα intensity map of the host galaxy of the repeating fast radio burst frb 121102 at a redshift of z = 0.193 obtained with the ao-assisted kyoto 3dii optical integral-field unit mounted on the 8.2 m subaru telescope. we detected a compact hα-emitting (i.e., star-forming) region in the galaxy, which has a ... | hα intensity map of the repeating fast radio burst frb 121102 host galaxy from subaru/kyoto 3dii ao-assisted optical integral-field spectroscopy |
for low-frequency radio astronomy, software correlation and beamforming on general purpose hardware is a viable alternative to custom designed hardware. lofar, a new-generation radio telescope centered in the netherlands with international stations in germany, france, ireland, poland, sweden and the uk, has successfull... | cobalt: a gpu-based correlator and beamformer for lofar |
the earth's ionosphere refracts radio waves incident on an interferometer, resulting in shifts to the measured positions of radio sources. we present a method to smoothly remove these shifts and restore sources to their reference positions, in both the catalogue and image domains. the method is applicable to instrument... | de-distorting ionospheric effects in the image plane |
astronomical radio signals are subjected to phase dispersion while traveling through the interstellar medium. to optimally detect a short-duration signal within a frequency band, we have to precisely compensate for the unknown pulse dispersion, which is a computationally demanding task. we present the “fast dispersion ... | an accurate and efficient algorithm for detection of radio bursts with an unknown dispersion measure, for single-dish telescopes and interferometers |
aims: gas outflows are believed to play a pivotal role in shaping galaxies, as they regulate both star formation and black hole growth. despite their ubiquitous presence, the origin and the acceleration mechanism of these powerful and extended winds is not yet understood. direct observations of the cold gas component i... | evidence for feedback in action from the molecular gas content in the z ~ 1.6 outflowing qso xid2028 |
finding and classifying astronomical sources is key in the scientific exploitation of radio surveys. source-finding usually involves identifying the parts of an image belonging to an astronomical source, against some estimated background. this can be problematic in the radio regime, owing to the presence of correlated ... | convosource: radio-astronomical source-finding with convolutional neural networks |
we introduce the first ai-based framework for deep, super-resolution, wide-field radio interferometric imaging and demonstrate it on observations of the eso 137-006 radio galaxy. the algorithmic framework to solve the inverse problem for image reconstruction builds on a recent "plug-and-play" scheme whereby a denoising... | first ai for deep super-resolution wide-field imaging in radio astronomy: unveiling structure in eso 137-006 |
cosmic multimessenger backgrounds include relic diffuse components created in the early universe and contributions from individual sources. here, we study both type ia supernovae (sne ia) and core-collapse supernovae (ccsne) contributions to the diffuse neutrino and gamma-ray backgrounds in the mev regime referred to a... | cosmic supernova neutrino and gamma-ray backgrounds in the mev regime |
we use atacama large millimeter/submillimeter array and institute for radio astronomy in the millimeter 30 m telescope data to investigate the relationship between the spectroscopically traced dense gas fraction and the cloud-scale (120 pc) molecular gas surface density in five nearby, star-forming galaxies. we estimat... | do spectroscopic dense gas fractions track molecular cloud surface densities? |
we present atacama large millimeter/submillimeter array (alma) and karl g. jansky very large array (jvla) observations of the massive infrared dark cloud ngc 6334s (also known as irdc g350.56+0.44), located at the southwestern end of the ngc 6334 molecular cloud complex. the h13co+ and nh2d lines covered by the alma ob... | alma observations of ngc 6334s. i. forming massive stars and clusters in subsonic and transonic filamentary clouds |
context. the argentine institute of radio astronomy (iar) is equipped with two single-dish 30 m radio antennas capable of performing daily observations of pulsars and radio transients in the southern hemisphere at 1.4 ghz.aims: we aim to introduce to the international community the upgrades performed and to show that t... | upgraded antennas for pulsar observations in the argentine institute of radio astronomy |
the five-hundred-meter aperture spherical radio telescope (fast) is expected to complete its commissioning in 2019. fast will soon begin the commensal radio astronomy fast survey (crafts), a novel and unprecedented commensal drift scan survey of the entire sky visible from fast. the goal of crafts is to cover more than... | status and perspectives of the crafts extra-galactic hi survey |
we present the detection of rotationally modulated, circularly polarized radio emission from the t8 brown dwarf wise j062309.94-045624.6 between 0.9 and 2.0 ghz. we detected this high-proper-motion ultracool dwarf with the australian ska pathfinder in 1.36 ghz imaging data from the rapid askap continuum survey. we obse... | periodic radio emission from the t8 dwarf wise j062309.94-045624.6 |
wave effects in lensing form a rich phenomenon at the intersection of classical caustic singularities and quantum interference, yet are notoriously difficult to model. due to a large number of recently observed pulsars and fast radio bursts in radio astronomy and the prospected increase in sensitivity of gravitational ... | multiplane lensing in wave optics |
the next generation of wide-field cosmic microwave background (cmb) surveys are uniquely poised to open a new window into time-domain astronomy in the millimeter band. here, we explore the discovery phase space for extragalactic transients with near-term and future cmb experiments to characterize the expected populatio... | extragalactic millimeter transients in the era of next-generation cmb surveys |
we extend the source sample recently observed by the breakthrough listen (bl) initiative by including additional stars (with parallaxes measured by gaia) that also reside within the full width at half-maximum of the green bank 100-m telescope and parkes radio telescope target fields. these stars have estimated distance... | extending the breakthrough listen nearby star survey to other stellar objects in the field |
context. star formation (sf) is a multi-scale process in which the mode of fragmentation of the collapsing clump on scales of 0.1-1 pc determines the mass reservoir and affects the accretion process of the individual protostars on scales of 10-100 au.aims: we want to investigate the nearby (located at 1.63 ± 0.05 kpc) ... | multi-scale view of star formation in iras 21078+5211: from clump fragmentation to disk wind |
this review gives an introduction to spectrometers and discusses their use within radio astronomy. while a variety of technologies are introduced, particular emphasis is given to digital systems. three different types of digital spectrometers are discussed: autocorrelation spectrometers, fourier transform spectrometers... | spectrometers and polyphase filterbanks in radio astronomy |
the very demanding requirements of the ska-low instrument call for a challenging antenna design capable of delivering excellent performance in radiation patterns, impedance matching, polarization purity, cost, longevity, etc. this paper is devoted to the development (design and test of the first prototypes) of an activ... | skala, a log-periodic array antenna for the ska-low instrument: design, simulations, tests and system considerations |
we report alma observations of ngc 1052 to search for mass accretion in a gas-poor active galactic nucleus. we detected co emission representing a rotating ring-like circumnuclear disk (cnd) seen edge-on with a gas mass of 5.3 × 105 m⊙. the cnd has smaller gas mass than that in typical seyfert galaxies with circumnucle... | a massive molecular torus inside a gas-poor circumnuclear disk in the radio galaxy ngc 1052 discovered with alma |
pwkit is a collection of miscellaneous astronomical utilities in python, with an emphasis on radio astronomy, reading and writing various data formats, and convenient command-line utilities. utilities include basic astronomical calculations, data visualization tools such as mapping arbitrary data to color scales and tr... | pwkit: astronomical utilities in python |
we present a cosmic perspective on the search for life and examine the likely number of communicating extra-terrestrial intelligent (ceti) civilizations in our galaxy by utilizing the latest astrophysical information. our calculation involves galactic star formation histories, metallicity distributions, and the likelih... | the astrobiological copernican weak and strong limits for intelligent life |
the next-generation very large array (ngvla) is an astronomical observatory planned to operate at centimeter wavelengths (25 to 0.26 centimeters, corresponding to a frequency range extending from 1.2 ghz to 116 ghz). the observatory will be a synthesis radio telescope constituted of approximately 214 reflector antennas... | the next-generation very large array: a technical overview |
supernova remnants are commonly considered to produce most of the galactic cosmic rays via diffusive shock acceleration. however, many questions regarding the physical conditions at shock fronts, such as the magnetic-field morphology close to the particle acceleration sites, remain open. here we report the detection of... | x-ray polarimetry reveals the magnetic-field topology on sub-parsec scales in tycho's supernova remnant |
we identify multi-wavelength counterparts to 1147 submillimeter sources from the s2cosmos scuba-2 survey of the cosmos field by employing a recently developed radio+machine-learning method trained on a large sample of atacama large millimeter/submillimeter array (alma)-identified submillimeter galaxies (smgs), includin... | multi-wavelength properties of radio- and machine-learning-identified counterparts to submillimeter sources in s2cosmos |
we apply classical machine vision and machine deep learning methods to prototype signal classifiers for the search for extraterrestrial intelligence. our novel approach uses two-dimensional spectrograms of measured and simulated radio signals bearing the imprint of a technological origin. the studies are performed usin... | machine vision and deep learning for classification of radio seti signals |
in the third catalog of active galactic nuclei detected by the fermi-lat (3lac) clean sample, there are 402 blazar candidates of uncertain type (bcus). due to the limitations of astronomical observation or intrinsic properties, it is difficult to classify blazars using optical spectroscopy. the potential classification... | evaluating the optical classification of fermi bcus using machine learning |
context. very long baseline interferometry (vlbi) is a radio-astronomical technique whereby the correlated signal from various baselines is combined into an image of the highest possible angular resolution. due to the sparsity of the measurements, this imaging procedure constitutes an ill-posed inverse problem. for dec... | multiscale and multidirectional very long baseline interferometry imaging with clean |
the origin of petaelectronvolt (pev) astrophysical neutrinos is fundamental to our understanding of the high-energy universe. apart from the technical challenges of operating detectors deep below ice, oceans, and lakes, the phenomenological challenges are even greater than those of gravitational waves; the sources are ... | the hunt for extraterrestrial high-energy neutrino counterparts |
we present alma 1.3 mm observations of the hd 53143 debris disk-the first infrared or millimeter image produced of this ~1 gyr old solar analog. previous hst stis coronagraphic imaging did not detect flux along the minor axis of the disk, which could suggest a face-on geometry with two clumps of dust. these alma observ... | alma images the eccentric hd 53143 debris disk |
the low frequency component of the square kilometre array (ska1-low) will be an aperture phased array located at the murchison radio-astronomy observatory (mro) site in western australia. it will be composed of 512 stations, each consisting of 256 log-periodic dual-polarized antennas, and will operate in the low freque... | characterization of the ska1-low prototype station aperture array verification system 2 |
we report on an unusually bright observation of psr j1720-0533 using the five-hundred-meter aperture spherical radio telescope (fast). the pulsar is in a black widow system that was discovered by the commensal radio astronomy fast survey (crafts). by coincidence, a bright scintillation maximum was simultaneous with the... | unusual emission variations near the eclipse of black widow pulsar psr j1720-0533 |
metasurfaces are ultrathin structures which are constituted by an array of subwavelength scatterers with designable scattering responses. they have opened up unprecedented exciting opportunities for extraordinary wave engineering processes. on the other hand, frequency converters have drawn wide attention due to their ... | pure and linear frequency-conversion temporal metasurface |
the interactions between radio jets and the interstellar medium play a defining role for the coevolution of central supermassive black holes and their host galaxies, but observational constraints on these feedback processes are still very limited at redshifts z > 2. we investigate the radio-loud quasar pso j352.4034... | the impact of powerful jets on the far-infrared emission of an extreme radio quasar at z ∼6 |
we are developing a lumped element kinetic inductance detector (lekid) array able to operate in the w-band (75-110 ghz) in order to perform ground-based cosmic microwave background (cmb) and mm-wave astronomical observations. the w-band is close to optimal in terms of contamination of the cmb from galactic synchrotron,... | development of lumped element kinetic inductance detectors for the w-band |
star-forming galaxies produce gamma-rays primarily via pion production, resulting from inelastic collisions between cosmic-ray protons and the interstellar medium (ism). the dense ism and high star formation rates of luminous and ultra-luminous infrared galaxies (lirgs and ulirgs) imply that they should be strong gamma... | constraining gamma-ray emission from luminous infrared galaxies with fermi-lat; tentative detection of arp 220 |
we describe the design, validation, and commissioning of a new correlator termed `mwax' for the murchison widefield array (mwa) low-frequency radio telescope. mwax replaces an earlier generation mwa correlator, extending correlation capabilities and providing greater flexibility, scalability, and maintainability. mwax ... | mwax: a new correlator for the murchison widefield array |
recent radio astronomical observations have revealed that hc5n, the second shortest cyanopolyyne (hc2n+1n), is abundant around some massive young stellar objects (mysos), which is not predicted by classical carbon-chain chemistry. for example, the observed hc5n abundance toward the g28.28-0.36 myso is higher than that ... | cyanopolyyne chemistry around massive young stellar objects |
modern interferometers routinely provide radio-astronomical images down to subarcsecond resolution. however, interferometers filter out spatial scales larger than those sampled by the shortest baselines, which affects the measurement of both spatial and spectral features. complementary single-dish data are vital for re... | data combination: interferometry and single-dish imaging in radio astronomy |
we present a 324.5 mhz image of the national optical astronomy observatory boötes field that was made using very large array p-band observations. the image has a resolution of 5.6 × 5.1 arcsec, a radius of 2.05° and a central noise of ∼0.2 mjy beam-1. both the resolution and noise of the image are an order of magnitude... | megahertz peaked-spectrum sources in the boötes field i - a route towards finding high-redshift agn |
machine-learning techniques have been increasingly used in astronomical applications and have proven to successfully classify objects in image data with high accuracy. the current work uses archival data from the faint images of the radio sky at twenty centimeters (first) to classify radio galaxies into four classes: f... | morphological classification of compact and extended radio galaxies using convolutional neural networks and data augmentation techniques |
a radio source at the galactic center sgr a* is a prime supermassive black hole candidate and therefore key to developing our understanding of them. time variations in the 230 ghz band flux of sgr a* have been found with the atacama large millimeter/submillimeter array cycle 5 observations. measuring the flux density o... | time variations in the flux density of sgr a* at 230 ghz detected with alma |
the measurement of the deflection of starlight during a total solar eclipse on 29 may 1919 was the first verification of general relativity by an external team of scientists, brought einstein and his theory to the attention of the general public, and left a legacy of experimental testing that continues today. the disco... | the 1919 measurement of the deflection of light |
we report on variability and correlation studies using multiwavelength observations of the blazar mrk 421 during the month of 2010 february, when an extraordinary flare reaching a level of ∼27 crab units above 1 tev was measured in very high energy (vhe) γ-rays with the very energetic radiation imaging telescope array ... | the great markarian 421 flare of 2010 february: multiwavelength variability and correlation studies |
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