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we have used the goddard iram 2 millimeter observer (gismo) with the 30 m iram telescope to carry out a 2 mm survey of the galaxy’s central molecular zone. these observations detect thermal emission from cold interstellar medium dust, thermal free-free emission from ionized gas, and nonthermal synchrotron emission from... | 2 mm gismo observations of the galactic center. ii. a nonthermal filament in the radio arc and compact sources |
we present arcsecond-scale observations of the active galactic nuclei (agns) of seven nearby seyfert galaxies observed from the stratospheric observatory for infrared astronomy (sofia) using the 31.5 and 37.1 μm filters of the faint object infrared camera for the sofia telescope (forcast). we isolate unresolved emissio... | sofia/forcast resolves 30-40 μm extended dust emission in nearby active galactic nuclei |
next-generation spectro-polarimetric broadband surveys will probe cosmic magnetic fields in unprecedented detail, using the magneto-optical effect known as faraday rotation. however, non-parametric methods such as rmclean can introduce non-observable linearly polarised flux into a fitted model at negative wavelengths s... | removing non-physical structure in fitted faraday rotated signals: non-parametric qu-fitting |
i summarize the science drivers presented at the workshop for phase i of the square kilometre array: 'advancing astrophysics with the square kilometre array'. i build from the historical perspective of the original key science programs: 'science with a square kilometre array', and consider progress in astrophysics sinc... | square kilometre array key science: a progressive retrospective |
the next generation very large array project (ngvla) would represent a major step forward in sensitivity and resolution for radio astronomy, with ability to achieve 2 milli-arcsec resolution at 100 ghz (assuming a maximum baseline of 300 km). for science on spatial scales of >~ 1 arcsec, the ngvla project should con... | short spacing considerations for the ngvla |
we present ∼103 ks of chandra observations of the galaxy cluster spt-clj0528-5300 (spt0528, z = 0.768). this cluster harbors the most radio-loud (l 1.4ghz = 1.01 × 1033 erg s-1 hz-1) central active galactic nucleus (agn) of any cluster in the south pole telescope (spt) sunyaev-zeldovich survey with available x-ray data... | discovery of a powerful >1061 erg agn outburst in the distant galaxy cluster spt-clj0528-5300 |
surprisingly strong co emission has been observed from more than a dozen debris disks around nearby main-sequence stars. the origin of this co is unclear, in particular whether it is left over from the protoplanetary disk phase or is second-generation material released from collisions between icy bodies like debris dus... | a deep search for five molecules in the 49 ceti debris disk |
the critical component of radio astronomy radiometers built to detect redshifted 21-cm signals from cosmic dawn is the antenna element. we describe the design and performance of an octave bandwidth cone disc antenna built to detect this signal in the band 40 to 90 mhz. the cosmic dawn signal is predicted to be a wideba... | a floating octave bandwidth cone-disc antenna for detection of cosmic dawn |
a fascinating topic in radio astronomy is how to associate the complexity of observed radio structures with their environment in order to understand their interplay and the reason for the plethora of radio structures found in surveys. in this project, we explore the distortion of the radio structure of fanaroff–riley (... | bent it like frs: extended radio agn in the cosmos field and their large-scale environment |
the solar radio flux at f10.7 and f30 cm is required by most models characterizing the state of the earth's upper atmosphere, such as the thermosphere and ionosphere, to specify satellite orbits, re-entry services, collision avoidance maneuvers, and modeling of the evolution of space debris. we develop a method called ... | medium-term predictions of f10.7 and f30 cm solar radio flux with the adaptive kalman filter |
in radio astronomy, holography is a commonly used technique to create an image of the electric field distribution in the aperture of a dish antenna. the image is used to detect imperfections in the reflector surface. similarly, holography can be applied to phased array telescopes, in order to measure the complex gains ... | holographic calibration of phased array telescopes |
supernova remnants (snrs) are significant contributors of matter and energy to the interstellar medium. understanding the impact and the mechanism of this contribution requires knowledge of the physical size, energy, and expansion rate of individual snrs, which can only come if reliable distances can be obtained. we ai... | a new distance to the supernova remnant da 530 based on h i absorption of polarized emission |
this paper provides analyses of the emission beam structure of 76 'b'-named pulsars within the arecibo sky. most of these objects are included in both the gould & lyne and lofar high band surveys and thus complement our other works treating various parts of these populations. these comprise a further group of mostl... | radio pulsar beam geometry down to the 100-mhz band: 76 additional sources within the arecibo sky |
we report the detection of three large millimeter flaring events from the nearby sun-like, ϵ eridani, found in archival atacama large millimeter/submillimeter array (alma) 12 m and atacama compact array observations at 1.33 mm taken from 2015 january 17 to 18 and 2016 october 24 to november 23, respectively. this is th... | first millimeter flares detected from ϵ eridani with the atacama large millimeter/submillimeter array |
electromagnetic metamaterials at microwave frequencies are well established in industry and research. recent work has shown how a specific kind of metallic metamaterial can contribute towards improving the performance of the feedhorn antennas used in radio astronomy and satellite telecommunications. in this article, we... | a metamaterial with applications in broad band antennas used in radio astronomy and satellite communications |
context. a full spectral characterization of carbonaceous dust analogs is necessary to understand their potential as carriers of observed astronomical spectral signatures such as the ubiquitous uv bump at 217.5 nm and the far-ultraviolet (fuv) rise common to interstellar extinction curves.aims: our goal is to study the... | vuv spectroscopy of carbon dust analogs: contribution to interstellar extinction |
context. many radio continuum catalogs with different sensitivity limits and spatial resolutions are published via the vizier database at the centre de données astronomiques de strasbourg. the diversity of spatial resolutions of different catalogs makes the cross-identification of different flux density measurements of... | the specfind v3.0 catalog of radio continuum cross-identifications and spectra: reaching lower frequencies |
a collection of peer-reviewed research papers supporting the development of a next-generation very large array prepared by members of the astronomical community and compiled by the national radio astronomy observatory in preparation for the u.s. 2020 astronomy and astrophysics decadal survey conducted by the national r... | science with a next generation very large array |
the sun emits radiation at several wavelengths of the electromagnetic spectrum. in the optical band, the solar radius is 695 700 km, and this defines the photosphere, which is the visible surface of the sun. however, as the altitude increases, the electromagnetic radiation is produced at other frequencies, causing the ... | solar radius at subterahertz frequencies and its relation to solar activity |
the evidence for benzonitrile (c6h5cn) in the starless cloud core tmc-1 makes high-resolution studies of other aromatic nitriles and their ring-chain derivatives especially timely. one such species is phenylpropiolonitrile (3-phenyl-2-propynenitrile, c6h5c3n), whose spectroscopic characterization is reported here for t... | a rotational and vibrational investigation of phenylpropiolonitrile (c6h5c3n) |
aims: we intend to map the whole meteor complex of the long-period comet c/1979 y1 (bradfield), which is a proposed parent body of the july pegasids, no. 175 in the list of meteor showers established by the meteor data center (mdc) of the international astronomical union (iau).methods: for five perihelion passages of t... | regular and transitory showers of comet c/1979 y1 (bradfield) |
in this work, we present the results of seasonal astroclimate observations at the rt-70 radiotelescope construction site on the suffa plateau (2400 m above sea level). observations were performed automatically each 11 min round the year starting from november 2014. the shortand long-term laws of variations in the atmos... | the results of astroclimate observations in the short-wave length interval of the millimeter-wave range on the suffa plateau |
context. the future deployment of the square kilometer array (ska) will lead to a massive influx of astronomical data and the automatic detection and characterization of sources will therefore prove crucial in utilizing its full potential.aims: we examine how existing astronomical knowledge and tools can be utilized in... | utilization of convolutional neural networks for h i source finding. team forska-sweden approach to ska data challenge 2 |
the 12c/13c ratio has been measured toward a sample of planetary nebulae (pne) using millimeter observations of co, hcn, hnc, cn, and other species, conducted with the 12 m antenna and the submillimeter telescope of the arizona radio observatory. the observed nebulae spanned the entire lifetime of pne, from ∼900 to 12,... | carbon isotope ratios in planetary nebulae: the unexpected enhancement of 13c |
space-based vlbi imaging can dramatically improve state-of-the-art astronomical radio-imaging resolution by enabling significantly longer baseline distances and eliminating atmospheric-attenuation constraints on rf carrier imaging wavelength. however, smaller space-based apertures and sensitivity constraints impose cha... | high-rate 256+ gbit/s laser communications for enhanced high-resolution imaging using space-based very long baseline interferometry (vlbi) |
the young and well-studied planetary nebula (pn) ngc 7027 harbors significant molecular gas that is irradiated by luminous, pointlike uv (central star) and diffuse (shocked nebular) x-ray emission. this nebula represents an excellent subject to investigate the molecular chemistry and physical conditions within photon- ... | mapping ngc 7027 in new light: co+ and hco+ emission reveal its photon- and x-ray-dominated regions |
atmospheric conditions have a major impact on the quality of ground-based astronomy observations. among atmospheric molecular gases, water vapour presents a significant challenge in ground-based astronomical observations in spectral bands ranging from radio to infrared. the impact of water vapour on astronomical observ... | statistics of precipitable water vapour above the sites of the 6-m big telescope alt-azimuthal and new 3-m large solar telescope using era5 data |
quantifying the volumes and geologic nature of lunar volcanic eruptions is important for constraining the thermal and geologic evolution of the moon. cryptomaria are effusive, basaltic lava flows on the moon that were subsequently buried, and therefore hidden, by higher-albedo basin and crater ejecta. radar offers the ... | burial depths of extensive shallow cryptomaria in the lunar schiller-schickard region |
the cassegrain telescope, made of a concave primary mirror and a convex secondary mirror, is widely utilized for modern astronomical observation. however, the existence of curved mirrors inevitably results in bulky configurations. here, we propose a new design of the miniaturized cassegrain telescope by replacing the c... | optical telescope with cassegrain metasurfaces |
when does the presence of an outlier in some measured property indicate that the outlying object differs qualitatively, rather than quantitatively, from other members of its apparent class? historical astronomical examples include the many types of supernovae and short versus long gamma-ray bursts. a qualitative differ... | when outliers are different |
deep learning (dl) has shown remarkable results in solving inverse problems in various domains. in particular, the tikhonet approach is very powerful in deconvolving optical astronomical images. however, this approach only uses the ℓ2 loss, which does not guarantee the preservation of physical information (e.g., flux a... | shapenet: shape constraint for galaxy image deconvolution |
fast radio bursts (frbs) were discovered only in 2007. however, the number of known events and sources of repeating bursts grows very rapidly. in the near future, the number of events will be ≳104 and the number of repeaters ≳100. presently, there is a consensus that most of the sources of frbs might be neutron stars (... | future of neutron star studies with fast radio bursts |
multi-wavelength observations of mature supernova remnants (snrs), especially with recent advances in γ-ray astronomy, make it possible to constrain energy distribution of energetic particles within these remnants. in consideration of the snr origin of galactic cosmic rays and physics related to particle acceleration a... | evolution of high-energy particle distribution in mature shell-type supernova remnants |
we first present the noise characteristics of the receiving systems including l, s, c, and x bands for the tm65 m radio telescope. the measurement methods for the system temperature have been discussed. the important influences, including the non-linearity error, feed network insertion loss, mismatch errors, and so on ... | measurements and analysis of system noise temperature of the low-frequency bands for the tm65 m radio telescope |
context. dinitriles with a saturated hydrocarbon skeleton and a -c≡n group at each end can have large electric dipole moments. their formation can be related to highly reactive radicals such as ch2cn, c2n, or cn. thus, these saturated dinitriles are potential candidates to be observed in the interstellar medium (ism).a... | the millimeter-wave spectrum and astronomical search of succinonitrile and its vibrational excited states |
context. recent observations suggest a scenario in which filamentary structures in the interstellar medium represent the first step towards clumps/cores and eventually star formation. the densest filaments would then fragment into prestellar cores owing to gravitational instability.aims: we seek to understand the roles... | extended ammonia observations towards the integral-shaped filament |
context. we 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. we determined line intensities of n-propyl cyanide in the ground vibrational states... | laboratory spectroscopic study and astronomical detection of vibrationally excited n-propyl cyanide |
based on 5 yr of observations with the 40-foot telescope at green bank observatory (gbo), reichart & stephens found that the radio source cassiopeia a had either faded more slowly between the mid-1970s and late 1990s than baars et al. had found it to be fading between the late 1940s and mid-1970s, or that it had re... | the fading of cassiopeia a, and improved models for the absolute spectrum of primary radio calibration sources |
the einstein's equivalence principle can be tested by using parametrized post-newtonian parameters, of which the parameter γ has been constrained by comparing the arrival times of photons with different energies. it has been constrained by a variety of astronomical transient events, such as gamma-ray bursts (grbs), fas... | testing the einstein's equivalence principle with polarized gamma-ray bursts |
we present a multiwavelength study of the oh megamaser galaxy iras16399-0937, based on new hubble space telescope (hst)/advanced camera for surveys f814w and hα+[n ii] images and archive data from hst, two micron all sky survey, spitzer, herschel and the very large array. this system has a double nucleus, whose norther... | an embedded active nucleus in the oh megamaser galaxy iras16399-0937 |
in this work, we studied the galactic center supermassive black hole (smbh), sagittarius a* (sgr a*), with the kvn and vera array (kava)/east asian vlbi network (eavn) monitoring observations. especially in 13 may 2019, sgr a* experienced an unprecedented bright near infra-red (nir) flare; so, we find a possible counte... | monitoring the size and flux density of sgr a* during the active state in 2019 with east asian vlbi network |
pulsar candidate sifting is an essential process for discovering new pulsars. it aims to search for the most promising pulsar candidates from an all-sky survey, such as the high time resolution universe (htru), green bank northern celestial cap (gbncc), five-hundred-meter aperture spherical radio telescope, etc. recent... | pulsar candidate sifting using multi-input convolution neural networks |
the current generation of radio and millimeter telescopes, particularly the atacama large millimeter array (alma), offers enormous advances in observing capabilities. while these advances represent an unprecedented opportunity to facilitate scientific understanding, the increased complexity in the spatial and spectral ... | using contour trees in the analysis and visualization of radio astronomy data cubes |
we present optical time-resolved multiband photometry of the black widow binary millisecond pulsar j2052+1219 using direct-imaging observations with the 2.1-m telescope of the observatorio astronomico nacional san pedro mártir (oan-spm), mexico. the observations reveal a variable optical source whose position and perio... | optical detection of the black widow binary psr j2052+1219 |
we have selected 43 southern massive star-forming regions to study the spatial distribution of hnco 404-303, sio 2-1, and hc3n 10-9 line emission and to investigate their spatial association with the dust emission. the morphology of hnco 404-303 and hc3n 10-9 agrees well with the dust emission. hc3n 10-9 tends to origi... | extended hnco, sio, and hc3n emission in 43 southern star-forming regions |
forthcoming astronomical surveys are expected to detect new sources in such large numbers that measuring their spectroscopic redshift measurements will not be practical. thus, there is much interest in using machine learning to yield the redshift from the photometry of each object. we are particularly interested in rad... | quasar photometric redshifts from incomplete data using deep learning |
we report ultra-wideband (0.4-4.0 ghz) observation of coherent radio emission via electron cyclotron maser emission (ecme) produced by the hot magnetic star hd 142990. with nearly perpendicular rotation and magnetic dipole axes, it represents an extreme case of oblique rotators. the large obliquity is predicted to caus... | peculiar spectral property of coherent radio emission from a hot magnetic star: the case of an extreme oblique rotator |
we report multifrequency vlbi studies of the subparsec scale structure of the two-sided jets in the nearby radio galaxy ngc 4261. our analyses include new observations using the source frequency phase referencing technique with the very long baseline array at 44 and 88 ghz, as well as archival data at 15 and 43 ghz. ou... | kinematics and collimation of the two-sided jets in ngc 4261: vlbi study on subparsec scales |
we carried out an observational search for the recently discovered molecule h2nc, and its more stable isomer h2cn, toward eight cold dense clouds (l1544, l134n, tmc-2, lupus-1a, l1489, tmc-1 nh3, l1498, and l1641n) and two diffuse clouds (b0415+379 and b0355+508) in an attempt to constrain its abundance in different ty... | the chemistry of h2nc in the interstellar medium and the role of the c + nh3 reaction |
interstellar clouds are sites of active organic chemistry (1). many small, gasphase molecules are found in the dark parts of the clouds that are protected from ultraviolet (uv) photons, but these molecules photodissociate in the external layers of the cloud that are exposed to stellar radiation (see the photo). these i... | detecting the building blocks of aromatics |
spectral observations with high temporal and frequency resolution are of great significance for studying the fine structures of solar radio bursts. in addition, it is helpful to understand the physical processes of solar eruptions. in this paper, we present the design of a system to observe solar radio bursts with high... | design of a high-resolution antenna array solar observing system for radio frequencies of 25-110 mhz |
context. almost 200 different species have been detected in the interstellar medium (ism) during the last decades, revealing not only simple species but complex molecules with more than six atoms. other exotic compounds, like the weakly-bound dimer (h2)2, have also been detected in astronomical sources like jupiter.aim... | the co-h2 van der waals complex and complex organic molecules in cold molecular clouds: a tmc-1c survey |
context. one of the biggest unsolved mysteries of modern astrochemistry is understanding chemical formation pathways in the interstellar medium (ism) and circumstellar environments. the detections (or even nondetections) of molecules composed of low-abundance atomic species (such as s, p, si, and mg) may help to constr... | expanding the submillimeter wave spectroscopy and astronomical search for thioacetamide (ch3csnh2) in the ism |
the deployable low-band ionosphere and transient experiment (dlite) is a four-element interferometric radio telescope made from mostly commercial off-the-shelf parts to minimize costs and maximize ease of deployment. it operates in the high frequency and very high frequency (vhf) regimes, nominally in a 30-40 mhz band,... | the deployable low-band ionosphere and transient experiment |
the status of searches for possible variation in the constants of nature from astronomical observation of molecules is reviewed, focusing on the dimensionless constant representing the proton-electron mass ratio μ =mp/me. the optical detection of h2 and co molecules with large ground-based telescopes (as the eso-vlt an... | search for varying constants of nature from astronomical observation of molecules |
the receiver is an important device for detecting weak radio signals in radio astronomy. the amplitude calibration of the receiver is to convert the response of the receiver for radio source into the flow density in astronomy. the conventional method is to convert the amplitude response of the receiver itself into an e... | research on k-band receiver noise calibration based on chopper wheel technology |
interplanetary scintillations make it possible to create three-dimensional, time- dependent distributions of the solar wind velocity. combined with the magnetic field observations in the solar photosphere, they help perform solar wind simulations in a genuinely time-dependent way. interplanetary scintillation measureme... | modeling solar wind with boundary conditions from interplanetary scintillations |
the grandproto300 (gp300) experiment is the first stage of the giant radio array for neutrino detection (grand) project. it will be deployed between 2020 and 2021 in a radio-quiet area, at $3000\,$m of altitude at the rim of the tibetan plateau, over a total surface of $200\,$km$^2$. the primary goal of gp300 is to dem... | the grandproto300 experiment: a pathfinder with rich astroparticle and radio-astronomy science case |
new generation radio interferometers encode signals from thousands of antenna feeds across large bandwidth. channelizing and correlating this data requires networking capabilities that can handle unprecedented data rates with reasonable cost. the canadian hydrogen intensity mapping experiment (chime) correlator process... | ice-based custom full-mesh network for the chime high bandwidth radio astronomy correlator |
we compare first-order (refractive) ionospheric effects seen by the mwa with the ionosphere as inferred from gps data. the first-order ionosphere manifests itself as a bulk position shift of the observed sources across an mwa field of view. these effects can be computed from global ionosphere maps provided by gps analy... | ionospheric modelling using gps to calibrate the mwa. i: comparison of first order ionospheric effects between gps models and mwa observations |
this paper presents an overview of methods for mitigating radio frequency interference (rfi) in radio science data. the primary purpose of mitigation is to assist observatories to take useful data outside frequency bands allocated to the science services (radio astronomy service (ras) and earth exploration service (ees... | implementing rfi mitigation in radio science |
using a combination of ground-based and hubble space telescope imaging, we have constructed a catalog of 179 supernova remnants (snrs) and snr candidates in the nearby spiral galaxy m51. follow-up spectroscopy of 66 of the candidates confirms that 61 of these are snrs and suggests that the vast majority of the unobserv... | optical identification and spectroscopy of supernova remnants in the galaxy m51 |
we use chandra x-ray observations to look for evidence of a recoiling black hole from the brightest cluster galaxy in abell 2261 (a2261-bcg). a2261-bcg is a strong candidate for a recoiling black hole because of its large, flat stellar core, revealed by hubble space telescope imaging observations. we took 100 ks observ... | chandra observations of abell 2261 brightest cluster galaxy, a candidate host to a recoiling black hole |
damped lyman- α absorber (dla) of hi 21 cm system is an ideal probe to directly measure cosmic acceleration in real-time cosmology via sandage-loeb (sl) test. during short observations toward two dlas in the commissioning progress of fast, we manage to exhibit an hi 21 cm absorption feature from pks1413+135 spectrum in... | toward a direct measurement of the cosmic acceleration: the first preparation with fast |
we report on the measurements of radio frequency interference (rfi) at mount timau, kupang, indonesia, which is intended to host a future radio astronomy observatory. these measurements were taken twice in october 2020 and december 2020 to obtain the rfi environment, at frequencies between 70 and 7000 mhz. due to the l... | radio frequency interference measurements for a radio astronomy observatory site in indonesia |
the vanishing & appearing sources during a century of observations (vasco) project investigates astronomical surveys spanning a time interval of 70 years, searching for unusual and exotic transients. we present herein the vasco citizen science project, which can identify unusual candidates driven by three different... | launching the vasco citizen science project |
radio observations of low-mass star formation in molecular spectral lines have rapidly progressed since the advent of the atacama large millimeter/submillimeter array (alma). the gas distribution and its kinematics within a few hundreds of astronomical unit scale around a class 0-i protostar are spatially resolved, and... | feria: flat envelope model with rotation and infall under angular momentum conservation |
radio astronomy is undergoing a renaissance, as the next generation of instruments provides a massive leap forward in collecting area and therefore raw sensitivity. however, to achieve this theoretical level of sensitivity in the science data products, we need to address the much more pernicious systematic effects, whi... | chiles. vii. deep imaging for the chiles project, an ska prototype |
recent advancements in transistor technology, such as the 35 nm inp hemt, allow for the development of monolithic microwave integrated circuit (mmic) low noise amplifiers (lnas) with performance properties that challenge the hegemony of sis mixers as leading radio astronomy detectors at frequencies as high as 116 ghz. ... | broadband mmic lnas for alma band 2+3 with noise temperature below 28 k |
the results of observations of the pulsar b0301+19 (j0304+1932) carried out on the large scanning antenna of the pushchino radio astronomy observatory at 111 mhz during 2012-2017 are analyzed. the regular generation of powerful individual pulses at the longitudes of both components of the mean profile of the pulsar, cl... | studies of giant pulses from the pulsar b0301+19 (j0304+1932) at 111 mhz |
we investigate the nature of dense gas in the 3-10 pc circumnuclear ring (cnr) in the galactic center of the milky way, which is a structure that may be dynamically connecting the supermassive black hole sgr a* with the central molecular zone at the 100 pc scale, and is the closest reservoir of molecular gas to the mas... | fifi-ls observations of the circumnuclear ring— probing the high-density phase of the pdr |
fast radio bursts (frbs) are astronomical transients with millisecond timescales occurring at cosmological distances. the observed time lag between different energies of each frb is well described by the inverse-square law of the observed frequency, i.e., dispersion measure. therefore, frbs provide one of the ideal lab... | upper limits on einstein's weak equivalence principle placed by uncertainties of dispersion measures of fast radio bursts |
we announce an upgrade of the iau mdc photographic and video meteor orbits database. a sample of 8916 radio-meteor data obtained by the radar observations at the hissar (gissar) astronomical observatory, dushanbe, tajikistan, have been added to the database. along with the radiant coordinates, velocities, and orbital e... | iau mdc meteor orbits database - a sample of radio-meteor data from the hissar observatory |
very long baseline interferometry (vlbi) experiments are organized within the geodetic, astrometric and astronomical communities for different applications, requiring different observation strategies adopted in scheduling. currently, the next-generation geodetic and astrometric vlbi global observing system (vgos) is be... | bridging astronomical, astrometric and geodetic scheduling for vgos |
the pressure to increase the sensitivity of instrumentation has pushed the use of cryogenic low noise amplifier (lna) technology into a growing number of fields. these areas range from radio astronomy and deep space communications to fundamental physics. in this context manufacturing for cryogenic environments requires... | thermal conductivity of silver loaded conductive epoxy from cryogenic to ambient temperature and its application for precision cryogenic noise measurements |
a new stepped septum-type waveguide circular polarizer (sst-cp) was developed to operate in the 230 ghz band for radio astronomy, especially submillimeter-band vlbi observations. for previously reported sst-cp models, the 230 ghz band is too high to achieve the design characteristics in manufactured devices because of ... | a new approach to suppress the effect of machining error for waveguide septum circular polarizer at 230 ghz band in radio astronomy |
as of march 2020 the tns serves as the official name server and hub for distribution of frb events. at the request of this community, the tns now operates two engines for designation of names, the original 'yyyyabc' (currently serving at/sn), and now also 'yyyymmddabc' for frbs (and potential future communities requiri... | fast radio bursts (frbs) now reported to and distributed via the tns |
radio frequency interference (rfi) has historically plagued radio astronomy, worsening with the rapid spread of electronics and increasing telescope sensitivity. we present a multi-dimensional probabilistic framework for characterizing the rfi environment around a radio astronomy site that uses data from the telescope ... | multi-dimensional radio frequency interference framework for characterizing radio astronomy observatories |
in the context of radio-astronomical observations, laboratory experiments constitute a cornerstone in the interpretation of rich line surveys due to the concomitant presence of numerous emitting molecules. here, we report the investigation of three different rotational transitions of mono-deuterated ammonia (nh2d), a s... | deuterium hyperfine splittings in the rotational spectrum of nh2d as revealed by lamb-dip spectroscopy |
an efficient method for achieving an antipodal vivaldi antenna array with filtering performance based on spoof surface plasmon polariton (sspp) metamaterial is proposed. the array is fed by a 1-to-8 power divider integrated with sspp structures—named sspp-i. the loaded sspp-i obtains high cutoff frequency at 24 ghz. bo... | an antipodal vivaldi antenna array based on spoof surface plasmon polariton metamaterial with 5g mm wave suppression |
we show that, in addition to specific science goals, there is a strong case for conducting an all-sky (i.e. the visible 3-pi steradians) ska continuum survey which does not fit neatly into conventional science cases. history shows that the greatest scientific impact of most major telescopes (e.g., hst, vla) lies beyond... | the ska mid-frequency all-sky continuum survey: discovering the unexpected and transforming radio-astronomy |
multi-messenger astronomy requires the use and development of telescopes and detectors for temporal observations across all the electromagnetic spectrum. the interest of our team is towards time-domain (or longitudinal, in the jargon of storage ring diagnostics) detectors able to make observations over the time rather ... | fast transient infrared detection for time-domain astronomy |
one of our greatest challenges in cosmology is understanding the origin of the structure of the universe. i will describe how the cosmic microwave background has provided a window for probing the initial conditions from which structure evolved and seeded the formation of the galaxies, and the outstanding issues that re... | towards the limits of cosmology |
the angular size of the smallest, compact radio source that can be observed in the solar atmosphere is one of the intriguing questions in low-frequency radio astronomy. this is important to understand density turbulence in the solar corona and the related angular broadening of the radio source sizes. we used a two-elem... | the first low-frequency radio observations of the solar corona on ≈200 km long interferometer baseline |
fast radio bursts (frbs) represent one of the most exciting astrophysical discoveries of the recent past. the study of their low-frequency emission, which was only effectively picked up about ten years after their discovery, has helped shape the field thanks to some of the most important detections to date. observation... | the low frequency perspective on fast radio bursts |
the iram plateau de bure interferometer (pdbi) is being upgraded to a new powerful millimeter-wave radio astronomy facility called the northern extended millimeter array (noema) which will double the number of the 15-m diameter antennas from six to 12. all antennas will be equipped with a new generation of dual-polariz... | the front-end of the noema interferometer |
we present the e-field parallel imaging calibration (epical) algorithm, which addresses the need for a fast calibration method for direct imaging radio astronomy correlators. direct imaging involves a spatial fast fourier transform of antenna signals, alleviating an o(na ^2) computational bottleneck typical in radio co... | an efficient feedback calibration algorithm for direct imaging radio telescopes |
context. the fermi/lat instrument has detected about two thousand extragalactic high energy (e ≥ 100 mev) γ-ray sources. one of the brightest is 3fgl j1603.9-4903; it is associated to the radio source pmn j1603-4904. its nature is not yet clear, it could be either a very peculiar bl lac or a compact symmetric object ra... | optical-nir spectroscopy of the puzzling γ-ray source 3fgl 1603.9-4903/pmn j1603-4904 with x-shooter |
we report a ∼6.1 yr quasi-periodicity for the blazar s5 0716+714 using the radio light curves at 4.8, 8 and 14.5 ghz observed by the university of michigan radio astronomical observatory (umrao) from 1981 to 2012, by means of the jurkevich, discrete correlation function (dcf) and power spectral analysis techniques. the... | radio variability of the blazar s5 0716+714: a ∼6.1 year quasi-periodicity |
new and upcoming radio interferometers will produce unprecedented amount of data that demand extremely powerful computers for processing. this is a limiting factor due to the large computational power and energy costs involved. such limitations restrict several key data processing steps in radio interferometry. one suc... | data multiplexing in radio interferometric calibration |
in this paper we present the electromagnetic modeling and beam pattern measurements of a 16-elements ultra wideband sparse random test array for the low frequency instrument of the square kilometer array telescope. we discuss the importance of a small array test platform for the development of technologies and techniqu... | ska aperture array verification system: electromagnetic modeling and beam pattern measurements using a micro uav |
the mexican space weather service (sciesmex in spanish) and national space weather laboratory (lance in spanish) were organized in 2014 and in 2016, respectively, to provide space weather monitoring and alerts, as well as scientific research in mexico. in this work, we present the results of the first joint observation... | first joint observations of space weather events over mexico |
feedback through energetic outflows has emerged as a key physical process responsible for transforming star-forming galaxies into the quiescent systems observed in the local universe. to explore this process, this paper focuses on a sample of massive and compact merger remnant galaxies hosting high-velocity gaseous out... | deviations from the infrared-radio correlation in massive, ultracompact starburst galaxies |
in this paper we build upon recent work in the radio astronomy community to experimentally demonstrate the viability of passive radar for space situational awareness. furthermore, we show that the six state parameters of objects in orbit may be measured and used to perform orbit characterisation/estimation. | surveillance of space using passive radar and the murchison widefield array |
in 1859, le verrier discovered the mercury perihelion advance anomaly. this anomaly turned out to be the first relativistic gravity effect observed. during the 157 years to 2016, the precisions and accuracies of laboratory and space experiments, and of astrophysical and cosmological observations on relativistic gravity... | solar-system tests of the relativistic gravity |
the substantial decrease in star formation density from z = 1 to the present day is curious given the relatively constant neutral gas density over the same epoch. future radio astronomy facilities, including the square kilometre array (ska) and pathfinder telescopes, will provide pioneering measures of both the gas con... | optimizing commensality of radio continuum and spectral line observations in the era of the ska |
we present the green bank telescope absorption survey of cold atomic hydrogen (≲300 k) in the inner halo of low-redshift galaxies. the survey aims to characterize the cold gas distribution and to address where the condensation—the process where ionized gas accreted by galaxies condenses into cold gas within the disks o... | distribution of cold (≲300 k) atomic gas in galaxies: results from the gbt h i absorption survey probing the inner halos (ρ < 20 kpc) of low-z galaxies |
active galactic nuclei (agn) are prominent astrophysical objects that can be observed throughout the whole universe. to understand the underlying physical processes and the different appearance of agn types, extensive samples are needed. nowadays, various agn catalogues are available at different wavebands. however, at... | a catalogue of active galactic nuclei from the first 1.5 gyr of the universe |
the kepler mission has shown that a significant fraction of all stars may have an earth-size habitable planet. a dramatic support was the recent detection of proxima centauri b. using a drake-equation like formalism i derive an equation for the abundance of biotic planets as a function of the relatively modest uncertai... | how far are extraterrestrial life and intelligence after kepler? |
this paper is the first in a series of papers describing the impact of antenna instrumental artefacts on the 21 cm cosmology experiments to be carried out by the low frequency instrument (ska1-low) of the square kilometre array telescope (ska), i.e. the cosmic dawn (cd) and the epoch of reionization (eor). the smoothne... | spectral performance of ska log-periodic antennas i: mitigating spectral artefacts in ska1-low 21 cm cosmology experiments |
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