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embrace@nançay is a prototype instrument consisting of an array of 4608 densely packed antenna elements creating a fully sampled, unblocked aperture. this technology is proposed for the square kilometre array and has the potential of providing an extremely large field of view making it the ideal survey instrument. we d... | characterization of a dense aperture array for radio astronomy |
we present a systematic search for two types of very unusual astronomical objects: galactic stars and spiral galaxies with double radio lobes, i.e. radio emission on opposite sides of the optical object, suggesting the ejection of jets from them. we designed an algorithm to search for pairs of radio sources straddling ... | a search for double-lobed radio emission from galactic stars and spiral galaxies |
the reflector system of five-hundred-meter aperture spherical radio telescope (fast) is designed as 4450 rigid panels supported by a flexible cable-net structure. we use 10 total stations to measure 2225 nodes of the cable-net and then control the shape of the reflectors. every time, it takes at least 35 minutes to fin... | recognition of fast reflector nodes based on canny operator |
we report chandra x-ray observations and optical weak-lensing measurements from subaru/suprime-cam images of the double galaxy cluster a2465 (z = 0.245). the x-ray brightness data are fit to a β model to obtain the radial gas density profiles of the northeast (ne) and southwest (sw) subcomponents, which are seen to dif... | the double galaxy cluster a2465. iii. x-ray and weak-lensing observations |
we announce an upgrade of the iau mdc photographic and video meteor orbits database. a sample of 8916 radio-meteor data determined by the radar observations at the hissar (gissar) astronomical observatory, dushanbe, tajikistan, are added to the database. along with the radiant coordinates, velocities, and orbital eleme... | iau mdc meteor orbits database -- a sample of radio-meteor data from the hissar observatory |
in this paper, we describe an hdf5 schema created to support the efficient visualization of the large image cubes that will be produced by ska phase 1 and precursor radio telescopes. we demonstrate how the "hdf5-idia" schema's features can improve the performance of visualization software, using both low-level metrics ... | development and application of an hdf5 schema for ska-scale image cube visualization |
the prompt emission of gamma-ray bursts (grbs) is a long-standing problem. the spectral-lag phenomenon can provide us with some clues about the emission mechanism. by analogy with the spectral lag of blazars at radio frequencies, we propose using the photosphere in the jet model to interpret the spectral lag of grbs. a... | interpreting the spectral lags of single-pulsed gamma-ray bursts via the photosphere in the jet model |
the project involving a new laboratory of space weather at the argentine marambio base in antarctica, required the assembly of an automatic thermal control for the interior of its main room, a meteorological station, a magnetometer, and a cosmic ray detector. this antarctic laboratory is part of an interdisciplinary pr... | state of the art and challenges of the argentine space weather laboratory (lamp) in the antarctic peninsula |
high-resolution pure rotational spectra of four alkylnaphthalenes were measured in the range of 6-15 ghz using a molecular-beam fourier-transform microwave spectrometer. both a- and b-type transitions were observed for 1-methylnaphthalene (1-mn), 1,2-dimethylnaphthalene (1,2-dmn), and 1,3-dimethylnaphthalene (1,3-dmn);... | high-resolution fourier-transform microwave spectroscopy of methyl- and dimethylnapthalenes |
the rotational spectra of three mono-substituted deuterium isotopologues of the anti conformer of ethanol have been measured between 35 and 500 ghz. one of these, ch2dch2oh, exists as two distinct conformers according to the position of the deuterium atom with respect to the molecular skeleton. the dataset was constrai... | millimetre-wave spectrum of the singly deuterated isotopologues of anti-ethanol |
the first james webb space telescope (jwst) image released was of galaxy cluster smacsj0723.3-7327, a lensing cluster at z = 0.39 showing detail only jwst can provide. while the majority of the focus has been on the brilliantly lensed galaxies at redshifts far beyond it, there is more to the story than it being just a ... | witnessing a galaxy cluster merger with jwst and a chandra x-ray temperature map |
we discuss the future scientific discovery and technical challenges for cm radio studies, presenting calculations and simulations of the science of a next generation vla (ngvla), an array with vastly improved resolution and sensitivity relative to alma and jvla, operating from ~1 ghz to 115 ghz, with an enhanced abilit... | next generation very large array: centimeter radio astronomy in the 2020s |
this paper presents an ultra-low noise l-band radio astronomical cryogenic receiver for the five-hundred-meter aperture spherical radio telescope (fast) telescope. the development of key low noise microwave parts of coupling low noise amplifier (coupling-lna) and conical quad-ridge orthogonal mode transducers (omt) and... | ultra-low noise l-band cryogenic astronomical receiver for the fast telescope |
a crucial part of a space mission for very-long baseline interferometery (vlbi), which is the technique capable of providing the highest resolution images in astronomy, is orbit determination of the mission's space radio telescope(s). in order to successfully detect interference fringes that result from correlation of ... | radioastron orbit determination and evaluation of its results using correlation of space-vlbi observations |
an ultralow-power k-band low-noise amplifier (lna) for next generation radio astronomical receivers fabricated in 65-nm cmos technology is presented in this letter. a gate-source transformer feedback is utilized for the simultaneous noise and impedance matching. in order to achieve high gain with limited dc power consu... | a submilliwatt k-band low-noise amplifier for next generation radio astronomical receivers in 65-nm cmos process |
the tunka radio extension (tunka-rex) is a digital radio array operating in the frequency band of 30-80 mhz and detecting radio emission from air-showers produced by cosmic rays with energies above 100 pev. the experimentis installed at the site of the taiga (tunka advanced instrument for cosmic rays and gamma astronom... | present status and prospects of the tunka radio extension |
this is an autobiographical account of my scientific career. my main research interest is the structure and assembly of galaxies. the assembly narrative has evolved from the monolithic and baryonic collapse picture of the early 1960s to the current hierarchical scenario underpinned by dark matter, and is still evolving... | galaxies, globular clusters, and dark matter |
we describe the discovery of a new kind of radio transient, which we call "early-riser bursts" or erbs. we found this new class of source by considering traditional radio searches, but extending into the complex plane of dispersion measure. erbs have the remarkable property of appearing before they are searched for. we... | a new kind of radio transient: erbs |
with the ever-increasing data rates in radio astronomy, a universal field programmable gate array (fpga)-based hardware platform which can be used at different locations in the signal processing chain, like a beamformer, data router or correlator, would reduce development time significantly. in this paper, we present t... | uniboard2, a generic scalable high-performance computing platform for radio astronomy |
channelization is one of the most important parts in a digital back-end(dbe) for radio astronomy. a dbe with wider bandwidth and higher resolution consumes larger amount of computing and memory resources, which results in much higher hardware cost. this paper presents an efficient channelization architecture, which con... | an efficient channelization architecture and its implementation for radio astronomy |
despite the popularity of the graphics processing unit (gpu) for general purpose computing, one should not forget about the practicality of the gpu for fast scientific visualization. as astronomers have increasing access to three-dimensional (3d) data from instruments and facilities like integral field units and radio ... | real-time colouring and filtering with graphics shaders |
we present a brief review of progress in the understanding of general spiral and elliptical galaxies, through merger, star formation and agn activities. with reference to case studies performed with the gmrt, we highlight the unique aspects of studying galaxies in the radio wavelengths where powerful quasars and bright... | tracking galaxy evolution through low-frequency radio continuum observations using ska and citizen-science research using multi-wavelength data |
in this article we discuss our implementation of a polyphase filter for real-time data processing in radio astronomy. the polyphase filter is a standard tool in digital signal processing and as such a well established algorithm. we describe in detail our implementation of the polyphase filter algorithm and its behaviou... | a polyphase filter for many-core architectures |
radio observations have resulted in some of the most fundamental and exciting discoveries in time-domain astronomy. here i demonstrate the potential for the next generation very large array (ngvla) to localize prompt centimeter-wavelength counterparts to the coalescing binary supermassive black holes (smbhs) to be dete... | flares from coalescing black holes in the centimeter-wavelength transient sky |
a subreflector adjustment system for the tianma 65 m radio telescope, administered by shanghai astronomical observatory, has been installed to compensate for gravitational deformation of the main reflector and the structure supporting the subreflector. the position and attitude of the subreflector are variable in order... | subreflector model depending on elevation for the tianma 65m radio telescope |
context. two main classes of imaging algorithms have emerged in radio interferometry: the clean algorithm and its multiple variants, and compressed-sensing inspired methods. they are both discrete in nature, and estimate source locations and intensities on a regular grid. for the traditional clean-based imaging pipelin... | leap: looking beyond pixels with continuous-space estimation of point sources |
the idl package reduces and analyzes radio astronomy data. it translates sdfits files into tmbidl format, and can average and display spectra, remove baselines, and fit gaussian models. | tmbidl: single dish radio astronomy data reduction package |
origin of the tev gamma ray emission from mgro j2019+37 discovered by the milagro experiment is investigated within the pulsar wind nebula (pwn) scenario using multiwavelength information on sources suggested to be associated with this object. we find that the synchrotron self-compton (ssc) mechanism of origin of the o... | constraints on the synchrotron self-compton mechanism of tev gamma ray emission from the milagro tev source mgro j2019+37 within the pulsar wind nebula scenario |
this is the first book written on using blender for scientific visualization. it is a practical and interesting introduction to blender for understanding key parts of 3d rendering and animation that pertain to the sciences via step-by-step guided tutorials. 3d scientific visualization with blender takes you through an ... | 3d scientific visualization with blender |
we have analyzed the rotational properties of 12 clumps using 13co (1-0) and c18o (1-0) maps of the five college radio astronomy observatory 13.7 m radio telescope. the clumps, located within molecular clouds, have radii (r) in the range of 0.06-0.27 pc. the direction of clump elongation is not correlated with the dire... | rotation of two micron all sky survey clumps in molecular clouds |
we present detection of 64 hii regions, three superbubbles and two optical supernova remnant (snr) candidates in the nearby irregular galaxy ngc 2366. the snr candidates were detected by applying [sii]hα ratio criterion to observations made with the 2-m rcc telescope at rozhen national astronomical observatory in bulga... | optical observations of the nearby galaxy ngc 2366 through narrowband h_alpha and [sii] filters. supernova remnants status |
we present the first installation and characterization of a phased array feed (paf) on the 64 m parkes radio telescope. the combined system operates best between 0.8 ghz and 1.74 ghz where the beamformed noise temperature is between 45 k and 60 k, the aperture efficiency ranges from 70% to 80%, and the effective field ... | testing a modified askap mark ii phased array feed on the 64 m parkes radio telescope |
the growing number of phased-array feeds (paf) being built for radio astronomy demonstrates an increasing need for low-noise amplifiers (lna), which are designed for repeatability, low noise, and ease of manufacture. specific design features that help to achieve these goals include the use of unpackaged transistors (fo... | a cryogenic sige low-noise amplifier optimized for phased-array feeds |
we present far-ir photometry and the infrared spectrum of the z = 3.9114 quasar/starburst composite system apm 08279+5255, obtained using the stratospheric observatory for infrared astronomy (sofia)/high-resolution airborne wideband camera+ (hawc+) and the spitzer space telescope infrared spectrograph. we decompose the... | constraining the active galactic nucleus and starburst properties of the ir-luminous quasar host galaxy apm08279+5255 at redshift 4 with sofia |
we investigated the suitability of the astronomical 15 ghz very long baseline array (vlba) observing program mojave-5 for estimation of geodetic parameters, such as station coordinates and earth orientation parameters. we processed a concurrent dedicated vlba geodesy program observed at 2.3 ghz and 8.6 ghz starting on ... | the use of astronomy vlba campaign mojave for geodesy |
the detection of an excess of emission at microwave frequencies with respect to the predicted free-free emission has been reported for several galactic h ii regions. here, we investigate the case of rcw 49, for which the cosmic background imager tentatively (∼3σ) detected anomalous microwave emission (ame) at 31 ghz on... | anomalous microwave emission in hii regions: is it really anomalous? the case of rcw 49 |
interplanetary scintillation (ips) induces intensity fluctuations in small angular size astronomical radio sources via the distortive effects of spatially and temporally varying electron density associated with outflows from the sun. these radio sources are a potential foreground contaminant signal for redshifted hi em... | the effect of interplanetary scintillation on epoch of reionization power spectra |
using the quantum cramér-rao bound from quantum estimation theory, we derive a fundamental quantum limit on the sensitivity of a temperature measurement of a thermal astronomical source. this limit is expressed in terms of the source temperature ts, input spectral bandwidth {{δ }}ν , and measurement duration t, subject... | quantum optimality of photon counting for temperature measurement of thermal astronomical sources |
understanding how galaxies form in the early universe and their subsequent evolution through cosmic time is a major goal of modern astrophysics. panchromatic look-back sky surveys significantly advanced the field in the past decades, and we are now entering an even more fruitful period - a 'golden age' of radio astrono... | radio continuum surveys and galaxy evolution: the agn view |
context. the 21 cm spectral line emission of atomic neutral hydrogen (h i) is one of the primary wavelengths observed in radio astronomy. however, the signal is intrinsically faint and the h i content of galaxies depends on the cosmic environment, requiring large survey volumes and survey depth to investigate the h i u... | a comparative study of source-finding techniques in h i emission line cubes using sofia, mtobjects, and supervised deep learning |
we present the results of noise-temperature measurements for four radio astronomy mmic low-noise amplifiers (lnas) at physical temperatures from 2 to 160 k. we observe and confirm recent reports that the noise temperature of an lna exhibits a quadratic dependence with respect to the physical temperature. we are also ab... | dependence of noise temperature on physical temperature for cryogenic low-noise amplifiers |
black holes in binary star systems are vital for understanding the process of pr oducing gravitational wave sources, understanding how supernovae work, and for p roviding fossil evidence for the high mass stars from earlier in the universe. at the present time, sample sizes of these objects, and especially of black hol... | astro2020 science white paper: populations of black holes in binaries |
the five-hundred-meter aperture spherical radio telescope (fast) passed its national acceptance inspection on 2020 january 11. this special issue includes a total of 15 papers, which are selected to introduce the status of fast's performance and demonstrate the key technologies applied to fast. the presented performanc... | preface: key technologies for enhancing the performance of fast |
we present the first determination of the abundance ratios of 13c substitutions of cyanoacetylene (hc3n), [h13cccn]:[hc13ccn]:[hcc13cn], in titan's atmosphere measured using millimeter-wave spectra obtained by the atacama large millimeter/submillimeter array. to compare the line intensities precisely, data sets that in... | 13c isotopic ratios of hc3n on titan measured with alma |
radio waves propagating through a medium containing irregularities in the spatial distribution of the electron density develop fluctuations in their intensities and phases. in the case of radio waves emitted from astronomical objects, they propagate through electron density irregularities in the interstellar medium, th... | interpretation of radio wave scintillation observed through lofar radio telescopes |
we report the discovery of mev-gev γ-ray emission by the fermi-lat positionally coincident with the tev pulsar wind nebula (pwn) hess j1554-550 within the host supernova remnant (snr) g327.1-1.1. the γ-ray emission is point-like and faint but significant (>4σ) in the 300 mev-2 tev energy range. we report here the fe... | mev-gev gamma-ray emission from snr g327.1-1.1 discovered by the fermi-lat |
the flux densities and current spectra of plerions and combined supernova remnants (snrs): 3c58, 3c144, g11.2-0.3, g21.5-0.9, and 3c396 are determined on an artificial moon (am) flux scale. the radio emission variability of the objects on different time scales is studied by multiple measurements using the rt-32 radio t... | radio emission variability of supernova remnants and a possible explanation of the phenomenon |
we present a morphological and physical analysis of a giant molecular cloud (gmc) using the carbon monoxide isotopologues (12co, 13co, c18o 3p2 → 3p1) survey of the galactic plane (mopra co southern galactic plane survey), supplemented with neutral carbon maps from the heat telescope in antarctica. the gmc structure (h... | the g332 molecular cloud ring: i. morphology and physical characteristics |
lieu et al. have recently claimed that it is possible to substantially improve the sensitivity of radio-astronomical observations. in essence, their proposal is to make use of the intensity of the photon shot noise as a measure of the photon arrival rate. lieu et al. provide a detailed quantum-mechanical calculation of... | on the use of shot noise for photon counting |
an active reflector is one of the three main innovations incorporated in the five-hundred-meter aperture spherical radio telescope (fast). the deformation of such a huge spherically shaped reflector into different transient parabolic shapes is achieved by using 2225 hydraulic actuators which change the position of the ... | emc design for actuators in the fast reflector |
this paper presents an ultra-wide bandwidth (uwb) low-frequency radio astronomical cryogenic receiver for the five-hundred-meter aperture spherical radio telescope (fast). it covers 6.6:1 bandwidth from 0.5 to 3.3 ghz. the receiver consists of a quad-ridged flared horn (qrfh), a cryogenic microwave unit, an optical tra... | an ultra-wide bandwidth low-frequency radio astronomical cryogenic receiver for fast telescope |
molecular astronomy is a field that is blooming in the era of large observatories such as the atacama large millimeter/submillimeter array (alma). with modern, sensitive, and high spectral resolution radio telescopes like alma and the square kilometer array, the size of the data cubes is rapidly escalating, generating ... | towards the prediction of molecular parameters from astronomical emission lines using neural networks |
we present a scalable distributed imaging framework for next-generation radio telescopes, managing the fourier transformation from apertures to sky (or vice-versa) with a focus on minimising memory load, data transfers and compute work. we use smooth window functions to isolate the influence between specific regions of... | imaging swiftly: streaming widefield fourier transformations for large-scale interferometry |
in quasi-optical heterodyne systems, such as those used in radio astronomy receivers, it is very typical to consider lo injection once the rf path has already been designed. in many cases, lo and rf optical paths share several optical components, and this imposes restrictions on the lo injection design. in this paper, ... | frequency independent lo injection in quasi-optical heterodyne systems |
detecting supernova remnant (snr) candidates 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 images and... | a deep learning approach for detecting candidates of supernova remnants |
radio frequency interference (rfi) is a serious issue in radio astronomy. this paper proposes a u-net network model with atrous convolution to detect rfi. using the ability of convolutional neural networks to extract image features of rfi, and learning rfi distribution patterns, the detection model of the rfi is establ... | radio frequency interference detection based on the ac-unet model |
the square kilometre array (ska) observatory is a next-generation radio astronomy facility, which is just started its construction, after successful completion of the design and early prototyping phases. with more than 12 countries currently participating in the international consortium to build this facility, the ska ... | the square kilometre array: current status and india's role in this upcoming facility |
the pure rotational spectrum of the ccl+ (x1σ+) cation has been observed for the first time using a cryogenic ion trap apparatus and applying an action spectroscopy scheme. the major isotopic species 12c35cl+ was observed up to the j = 4 ← 3 transition around 191 ghz and 12c37cl+ was observed up to j = 3 ← 2. all trans... | pure rotational spectrum of ccl+ |
aluminum and silicon are present in large quantities in the interstellar medium, making the triatomic species consisting of both elements intriguing with regard to the foundations of astrochemistry. spectroscopic parameters have been calculated via high-level ab initio methods to assist with laboratory and observationa... | spectroscopic properties of the astrochemical molecules [al, o, si] x(x = 0, +1) |
space electric and magnetic sensors (seams) is a system being designed for low frequency radio astronomical observations below 20mhz. seams consists of electric field vector sensor (efvs) followed by active matching stages, gain blocks, filters and data acquisition system. this paper details the design and development ... | fpga based data acquisition and processing system for space electric and magnetic sensors (seams) |
in the course of astronomical observations, with changes in angle of pitch, the large radio telescope will have different degrees of deformation in the sub-reflector support, back frame, main reflector etc, which will lead to the dramatic decline of antenna efficiency in both high and low elevation. a sub-reflector sys... | the position and attitude of sub-reflector modeling for tm65 m radio telescope |
delingha 13.7 m telescope is one of the most important radio telescopes in china. since installing superconducting spectroscopic array receiver (ssar) and adopting on the fly (otf) observation mode, the telescope has operated for nearly 10 years. during this period, a large number of astronomical observation projects h... | operation of multibeam receiver of delingha 13.7 m telescope |
the results of a study of the h2o and oh maser emission from the cool ir source iras 16293-2422 are presented. the observations analyzed were obtained in h2o lines with the 22-m telescope of the pushchino radio astronomy observatory during 1999-2015 and in oh lines with the nanç ay radio telescope (france). a large num... | long-term monitoring and interpretation of flares in the h2o maser emission of iras 16293-2422 |
results of a new series of observations of the anomalous pulsar b0943+10 carried out on the large scanning antenna and dkr-1000 radio telescope of the pushchino radio astronomy observatory at 112 and 62 mhz, respectively, are presented. several hundred pulse-arrival times (pats) obtained on various days in 2013-2016 th... | the character of pulse delays during radio bursts in the pulsar b0943+10 |
when a massive star explodes as a supernova, it injects a huge amount of energy into its surroundings. the resultant expanding blast-wave and its interaction with the surrounding medium is known as a supernova remnant (snr). the shock created by the supernova event is believed to be the primary accelerator of cosmic ra... | gamma-ray studies of stellar graveyards: fermi-lat observations of supernova remnants and spatially extended emission |
we investigate a sample of 622 blazars with measured fluxes at 12 wavebands across the radio-to-gamma-ray spectrum but without spectroscopic or photometric redshifts. this sample includes hundreds of sources with newly analyzed x-ray spectra reported here. from the synchrotron peak frequencies, estimated by fitting the... | an investigation of blazars without redshifts: not a missing population at high redshift |
accurate computational characterization of ethanimine (ch3nh), considered as an important possible precursor of amino acids, is now available. ethanimine has two e and z isomers and each isomer has two a and e substates. some lines of green bank telescope primos radio astronomy survey spectra in sagittarius b2 north (s... | potential spectral lines of ethanimine (ch3chnh) - an important possible precursor of amino acids |
context. the recent discovery of methyl acetate in orion kl makes vinyl acetate, ch3c=ooch=ch2, a potential molecule in the interstellar medium. we obtained very accurate spectroscopic constants in a comprehensive laboratory analysis of its rotational spectra which can be used to predict those transition frequencies to... | laboratory millimeter wave spectrum and astronomical search for vinyl acetate |
we present a study of the molecular co gas and mid/far-infrared radiation arising from the environment surrounding the wolf-rayet (wr) star 130. we use the multiwavelength data to analyse the properties of the dense gas and dust, and its possible spatial correlation with that of young stellar objects (ysos). we use 12c... | the infrared and molecular environment surrounding the wolf-rayet star wr 130 |
in this paper i review some recent progress in the studies on redshifted 21cm line observations. the 21cm line have long been an important radio spectral line in astronomical observations, but so far its observation is limited to low redshifts, due to the difficulty in detecting this line at high or mid redshifts. howe... | probing dark energy and primordial non-gaussianity with the 21cm line observations |
pulsars are natural clocks that can be used as laboratories for strong-field gravity, and as sensitive probes of the interstellar plasma along our line-of-sight. pulsar timing arrays (ptas) monitor a set of the most stable millisecond pulsars (msps) over many years to function as a galactic-scale gravitational wave (gw... | precision radio-frequency pulsar timing & interstellar scintillometry |
the use of computers and the role of women in radio astronomy and x-ray crystallography research at the cavendish laboratory between 1949 and 1975 have been investigated. we recorded examples of when computers were used, what they were used for and who used them from hundreds of papers published during these years. the... | scientific computing in the cavendish laboratory and the pioneering women computors |
taking the tianma radio telescope (tmrt) as an object, this paper focuses on the determination of temperature gradients and thermal deformations of the backup structure (bus) with the finite element method. to this end, a modeling and analysis method, which consists of a simplified fem and a four-component simulation p... | thermal analysis of the backup structure of the tianma telescope |
the upgraded gmrt (ugmrt) with its unprecedented sensitivity and high figure of merit, is expected to result in the discovery of a large population of pulsars including pulsars of previously unknown type. in the phase-2 of the gmrt high resolution southern sky (ghrss) survey with the ugmrt we will reach 1/4th of sensit... | time-domain astronomy with the gmrt: ugmrt to egmrt |
type i radio noise storms are believed to provide a diagnostic of electron acceleration in the corona. most type i bursts appear in chains of five or more individual bursts. an analysis of the chain properties may indicate electron density, height of emission source, and magnetic-field intensity. we studied 255 chains ... | analysis of chains of metric solar type i bursts |
the atacama large millimeter array (alma) is a radio interferometer composed of 66 antennas located on the chajnantor plateau at 5 km altitude in northern chile. with baselines of up to 16 km, alma provides unprecedented spatial resolution and sensitivity in the mm/submm wavelength range for the study of star and galax... | the alma science pipeline |
two possible sources of random and systematic errors of a new method for determining the parameters of the relative orientation of the catalogs of positions of extragalactic sources implementing the international celestial reference system (icrs) are investigated. this method is based on the median filtering of the dif... | on densification of the icrf catalog and the reliability of its link to the gaia catalog |
recently, an alternative model based on white dwarfs pulsars has been proposed to explain a class of pulsars known as soft gamma repeaters (sgr) and anomalus x-ray pulsars (axp) [1], usually named as magnetars. in this model, the magnetized white dwarfs can have surface magnetic field b ∼ 107 - 1010 g and rotate very f... | radio pulsar death lines to sgrs/axps and white dwarfs pulsars |
during the last decades, increasingly precise astronomical observations of the galactic centre region at radio, infrared, and x-ray wavelengths laid the foundations for a detailed understanding of the high-energy astroparticle physics of this most remarkable location in the galaxy. recently, observations of this region... | gamma rays from the galactic centre region |
the search for extra-terrestrial intelligence (seti) using radio telescopes is an area of research that is now more than 50 years old. thus far, both targeted and wide-area surveys have yet to detect artificial signals from intelligent civilisations. in this paper, i argue that the incidence of co-existing intelligent ... | seti reloaded: next generation radio telescopes, transients and cognitive computing |
for the real-time transient localization, there are large uncertainties of the fast radio burst (frb) positions due to the undersampled focal plane in cluster-fed telescopes. a novel focal-field feature matching algorithm based on a conditional generative adversarial network, f3m-cgan, is proposed for frb localization.... | feature matching conditional gan for fast radio burst localization with cluster-fed telescope |
science rationale: our knowledge of the internal structure of asteroids entirely relies on inferences from remote sensing observations of the surface combined with theoretical modeling [1]. is apophis a rubble-pile, as expected, or a monolithic rock, and how high is the porosity? what is the typical size of the constit... | droid: bistatic low-frequency radar sounding of 99942 apophis in 2029 |
at present, chinese vlbi network (cvn) consists of 5 antennas (seshan 25m, urumqi 25m, kunming 30m, miyun 50m and tianma 65m) and one data processing center in shanghai observatory, chinese academy of sciences. it is a synthetic aperture radio telescope with the equivalent diameter up to 3000 km. through e-vlbi (electr... | the recent progress of chinese vlbi network |
dorado is an astrophysics mission of opportunity that addresses two "frontier" discovery areas highlighted by the 2010 astronomy and astrophysics decadal survey: gravitational waves (gws) and time-domain astronomy. dorado provides the highest priority observational capability identified by the community in order to ful... | dorado: a wide-field ultraviolet imaging satellite for the multi-messenger era |
in the era of big data, radio astronomical image reconstruction algorithms are challenged to estimate clean images given limited computing resources and time. this article is driven by the need for large-scale image reconstruction for the future square kilometre array (ska), which will become in the next decades the la... | a parallel and automatically tuned algorithm for multispectral image deconvolution |
we present observations and analyses of the low-mass star-forming region, taurus molecular cloud-1 (tmc-1). cs (j = 2-1)/n2h+ (j = 1-0) and c17o (j = 2-1)/c18o (j = 2-1) were observed with the five college radio astronomy observatory and the seoul radio astronomy observatory, respectively. in addition, spitzer infrared... | dynamical timescale of pre-collapse evolution inferred from chemical distribution in the taurus molecular cloud-1 (tmc-1) filament |
astroaccelerate processes time-domain radio astronomy data. it offers a standalone code that can be used to process filterbank data and a library that performs gpu-accelerated single pulse processing (sps), fourier domain acceleration searching (fdas) and dedispersion in real-time on very large data-sets comparable to ... | astroaccelerate: accelerated software package for processing time-domain radio astronomy data |
this study proposes general criteria to identify a radio quiet zone (rqz) and a radio notification zone (rnz) for the installation of a radio astronomical observatory on-site and safeguard the radio astronomy spectrum specifically in tropical regions. this study focuses on areas with a medium population density. most r... | radio quiet and radio notification zones characteristics for radio astronomy in medium densely populated areas and humid tropical countries |
repeater systems in a geostationary orbit utilizing free-space optical-communication offer great potential to backup, process and archive large amounts of data collected or generated at remote locations. in contrast to existing or upcoming global satellite communication systems, such optical geo relays are able to prov... | connectivity services based on optical ground-to-space links |
we present a method to identify candidate quasars which combines optical/infrared color selection with radio detections from the low frequency array (lofar) at 150mhz. we apply this {method} in a region of 9 square degrees located in the boötes field, with a wealth of multi-wavelength data. our lofar imaging in the cen... | on the selection of high-z quasars using lofar observations |
radio pulsars have been responsible for many astonishing astrophysical and fundamental physics breakthroughs since their discovery 50 years ago. in this review i will discuss many of the highlights, most of which were only possible because of the provision of large-scale observing facilities. the next 50 years of pulsa... | the future of pulsar research and facilities |
over the last few years a number of software and hardware improvements have been implemented to the 32-m cassegrain radio telescope located near toruń. the 19-bit angle encoders have been upgraded to 29-bit in azimuth and elevation axes. the control system has been substantially improved, in order to account for a numb... | improving pointing of toruń 32-m radio telescope: effects of rail surface irregularities |
real-time searches for faint radio pulses from unknown radio transients are computationally challenging. detections become further complicated due to continuously increasing technical capabilities of transient surveys: telescope sensitivity, searched area of the sky, number of antennas or dishes, temporal and frequency... | the apertif monitor for bursts encountered in real-time (amber) auto-tuning optimization with genetic algorithms |
phased array feed (paf) technology is the next major advancement in radio astronomy in terms of combining high sensitivity and large field of view. the focal l-band array for the green bank telescope (flag) is one of the most sensitive pafs developed so far. it consists of 19 dual-polarization elements mounted on a pri... | commissioning of flag: a phased array feed for the gbt |
the requirements on the stability of the frequency reference in the square kilometer array (ska), as a radio astronomy interferometer, are given in terms of the maximum accepted degree of coherence loss caused by the instability of the frequency reference. in this paper, we analyze the relationship between the characte... | frequency reference stability and coherence loss in radio astronomy interferometers application to the ska |
we developed the <tt>pycraf</tt> python package, which provides functions and procedures for various tasks related to spectrum-management compatibility studies. this includes an implementation of itu-r rec. p.452 (itu-r, 2015), which allows to calculate the path attenuation arising from the distance and ter... | spectrum management and compatibility studies with python |
we recently discovered that the luminous radio-quiet quasi-stellar objects (qso) lbqs 0302-0019 at z = 3.286 is likely accompanied by an obscured agn at 20 kpc projected distance, which we dubbed jil. it represents the tightest candidate system of an obscured and unobscured dual agn at z > 3. to verify the dual agn ... | cosmic dance at z 3: detecting the host galaxies of the dual agn system lbqs 0302-0019 and jil with hawk-i+graal |
cold atomic hydrogen clouds are the precursors of molecular clouds. due to self-absorption, the opacity of cold atomic hydrogen may be high, and this gas may constitute an important mass component of the interstellar medium. atomic hydrogen gas can be cooled to temperatures much lower than found in the cold neutral med... | tracing the formation of molecular clouds in a low-metallicity galaxy: an h i narrow self-absorption survey of the large magellanic cloud |
we have carried out an integrated chronostratigraphic analysis of the alano di piave section, proposed gssp for the bartonian/priabonian boundary (late eocene). age constraints were derived independently from a floating cyclochronology based on carbon isotope and wt.% caco3 records, and 206pb/238u dating of zircons fro... | astrochronology and radio-isotopic dating of the alano di piave section (ne italy), candidate gssp for the priabonian stage (late eocene) |
the results of optical, radio, and gamma-ray observations of the blazar ao 0235+16 are presented, including photometric ( bv rijhk) and polarimetric ( r)monitoring carried out at st. petersburg state university and the central (pulkovo) astronomical observatory in 2007-2015, 43 ghz very long baseline interferometry rad... | variations of the blazar ao 0235+164 in 2006-2015 |
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