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in the framework of space debris, the orbit determination process is a fundamental step, both, for researchers and for satellite operators. the accurate knowledge of the orbit of space debris objects is needed to allow space debris characterization studies and to avoid unnecessary collision avoidance maneuvers. the acc... | analysis of laser ranges and angular measurements data fusion for space debris orbit determination |
the rapid development of x-ray astronomy has been made possible by widely deploying x-ray focusing telescopes on board many x-ray satellites. geant4 is a very powerful toolkit for monte carlo simulations and has remarkable abilities to model complex geometrical configurations. however, the library of physical processes... | geant4 simulations of a wide-angle x-ray focusing telescope |
in order to understand the diversity of classes observed in active galactic nuclei (agns), a geometrically and optically thick torus of gas and dust is required to obscure the central engine depending on the line of sight to the observer. we perform a simultaneous fitting of x-ray and mid-infrared (mid-ir) spectra to i... | physical parameters of the torus for the type 2 seyfert ic 5063 from mid-ir and x-ray simultaneous spectral fitting |
in this work, a novel kind of interesting spectral change, multiple spectral switches, is revealed for the first time. during the analysis of the evolution of the scattered spectrum for a newly proposed electromagnetic random source of circular frame upon a semisoft boundary medium in the far zone, it is shown that, wi... | multiple spectral switches generated by the scattering of a novel electromagnetic random source of circular frame upon a semisoft boundary medium |
a new generation telescope for objects at geosynchronous earth orbit (geo) was developed by shanghai astronomical observatory at the end of 2017, it's called focusgeo telescope. the goal is to observe nearly all the geo objects over the observation station near real-time. focusgeo telescope consists of three refracting... | focusgeo observations of space debris at geosynchronous earth orbit |
the visible integral-field replicable unit spectrograph (virus) consists of 156 identical spectrographs (arrayed as 78 pairs, each with a pair of spectrographs) fed by 35,000 fibers, each 1.5 arcsec diameter, at the focus of the upgraded 10 m hobby-eberly telescope (het). virus has a fixed bandpass of 350-550 nm and re... | virus: status and performance of the massively replicated fiber integral field spectrograph for the upgraded hobby-eberly telescope |
the focal-plane cameras of γ -ray telescopes frequently use light concentrators in front of the light sensors. the purpose of these concentrators is to increase the effective area of the camera as well as to reduce the stray light coming at large incident angles. these light concentrators are usually based on the winst... | design, optimization and characterization of the light concentrators of the single-mirror small size telescopes of the cherenkov telescope array |
finding a sample of the most massive clusters with redshifts z > 0.6 can provide an interesting consistency check of the λ cold dark matter (λcdm) model. here, we present results from our search for clusters with 0.6 ≲ z ≲ 1.0 where the initial candidates were selected by cross-correlating the rosat all sky survey (... | optical and sunyaev-zel'dovich observations of a new sample of distant rich galaxy clusters in the rosat all sky |
ast3-1 is the second-generation wide-field optical photometric telescope dedicated to time-domain astronomy at dome a, antarctica. here, we present the results of an i-band images survey from ast3-1 toward one galactic disk field. based on time-series photometry of 92,583 stars, 560 variable stars were detected with i ... | variable stars observed in the galactic disk by ast3-1 from dome a, antarctica |
we have developed a non-sequential ray-tracing simulation library, root-basedsimulatorforraytracing (robast), which is aimed to be widely used in optical simulations of cosmic-ray (cr) and gamma-ray telescopes. the library is written in c++, and fully utilizes the geometry library of the root framework. despite the imp... | robast: development of a root-based ray-tracing library for cosmic-ray telescopes and its applications in the cherenkov telescope array |
balloon-borne astronomy is unique in that it allows for a level of image stability, resolution, and optical backgrounds that are comparable to space-borne systems due to greatly reduced atmospheric interference, but at a fraction of the cost and over a significantly reduced development time-scale. instruments operating... | the design and development of a high-resolution visible-to-near-uv telescope for balloon-borne astronomy: superbit |
the daytime sky has recently been demonstrated as a useful calibration tool for deriving polarization cross-talk properties of large astronomical telescopes. the daniel k. inouye solar telescope and other large telescopes under construction can benefit from precise polarimetric calibration of large mirrors. several atm... | daytime sky polarization calibration limitations |
we studied the spectra of six z 2.2 quasars obtained with the x-shooter spectrograph at the very large telescope. the redshift of these sources and the x-shooter's spectral coverage allow us to cover the rest of the spectral range 1200-7000 å for the simultaneous detection of optical and ultraviolet lines emitted by th... | simultaneous detection and analysis of optical and ultraviolet broad emission lines in quasars at z 2.2 |
we characterize the chemical and physical conditions in an outflowing high-velocity cloud (hvc) in the inner galaxy. we report a supersolar metallicity of [o/h] = +0.36 ± 0.12 for the hvc at v lsr = 125.6 km s-1 toward the star hd 156359 (l = 328.°7, b = -14.°5, d = 9 kpc, z = -2.3 kpc). using archival observations fro... | caught in the act: a metal-rich high-velocity cloud in the inner galaxy |
we present h-band interferometric observations of the red supergiant (rsg) az cyg that were made with the michigan infra-red combiner (mirc) at the six-telescope center for high angular resolution astronomy (chara) array. the observations span 5 yr (2011-2016), which offers insight into the short and long-term evolutio... | long term evolution of surface features on the red supergiant az cyg |
during the last decade, there has been an explosive growth in survey data and deep learning techniques, both of which have enabled great advances for astronomy. the amount of data from various surveys from multiple epochs with a wide range of wavelengths, albeit with varying brightness and quality, is overwhelming, and... | survey2survey: a deep learning generative model approach for cross-survey image mapping |
integrated photonic spectrographs offer an avenue to extreme miniaturization of astronomical instruments, which would greatly benefit extremely large telescopes and future space missions. these devices first require optimization for astronomical applications, which includes design, fabrication and field-testing. given ... | potential of commercial sin mpw platforms for developing mid/high-resolution integrated photonic spectrographs for astronomy |
constraining the frequency of energy deposition in magnetically closed active region cores requires sophisticated hydrodynamic simulations of the coronal plasma and detailed forward modeling of the optically thin line-of-sight integrated emission. however, understanding which set of model inputs best matches a set of o... | understanding heating in active region cores through machine learning. ii. classifying observations |
we develop a novel hyperspectral imaging system using structured illumination in an slm-based michelson interferometer. in our design, we use a reflective slm as a mirror in one of the arms of a michelson interferometer, and scan the interferometer by varying the phase across the slm display. for achieving the latter, ... | adaptive hyperspectral imaging using structured illumination in a spatial light modulator-based interferometer |
neutrinos are guaranteed to be observable from the next galactic supernova (sn). optical light and gravitational waves are also observable, but may be difficult to observe if the location of the sn in the galaxy or the details of the explosion are unsuitable. the key to observing the next sn is to first use neutrinos t... | observing supernova neutrino light curves with super-kamiokande. iii. extraction of mass and radius of neutron stars from synthetic data |
during this time of global hardship caused by the lingering covid-19 pandemic, where unsustainable systems are being uncovered and amplified, there are silver linings. ground-based telescopic observatories are closed. and yet, remote work allows for new opportunities. innovate ways to communicate astronomy with the pub... | we are stardust — stories of us |
knowledge of the optical refractive index structure parameter cn2 is of interest for free space optics and ground-based optical astronomy, as it depicts the strength of the expected scintillation on the received optical waves. focus is given here to models using meteorological quantities coming from radiosonde measurem... | computation of optical refractive index structure parameter from its statistical definition using radiosonde data |
based on the database monitored by the 1.26 m national astronomical observatory-guangzhou university infrared/optical telescope, we studied the optical variabilities of fsrq 3c454.3. the monitoring period was from 2016 october 17 to 2018 december 14, and there were 6701 observations covering the g, r, and i bands (2196... | optical monitoring and variability analyses of the fsrq 3c 454.3 |
we present the validation of a transiting low-density exoplanet orbiting the m2.5 dwarf toi 620 discovered by the nasa transiting exoplanet survey satellite (tess) mission. we utilize photometric data from both tess and ground-based follow-up observations to validate the ephemerides of the 5.09 day transiting signal an... | a close-in puffy neptune with hidden friends: the enigma of toi 620 |
ground-based observations suffer from atmospheric turbulence perturbations, which seriously degrade the image quality. the seeing profile associated with the turbulence is critical to characterize an astronomical site. the optimal design and performance estimation of future solar ground-layer adaptive optics (glao) and... | the first solar seeing profile measurement with two apertures and multiple guide regions |
a range-resolved laser interferometer is the leading candidate for providing displacement metrology that can meet the stringent precision and low power dissipation requirements of cryogenic space astronomy missions. in prior work, a three-phase homodyne laser interferometer was developed using a simple optical and sign... | multiaxis applications of a cryogenic range-resolved laser interferometer |
this article aims at studying the characteristics of high-altitude wind at the ali observatory on the western tibetan plateau, as the high-altitude wind has been put forward as a critical parameter for site evaluation, especially for adaptive optics. we have run a meso-scale numerical weather research and forecasting (... | statistics and analysis of high-altitude wind above the western tibetan plateau |
b[e] stars are surrounded by cool and dense circumstellar environments where molecules and dust are formed. these stars are rare and display complex spectra whose photospheric features are frequently veiled by their circumstellar envelopes, making it difficult to assign them spectral types and evolutionary phases. on t... | near-infrared spectra of a sample of galactic unclassified b[e] stars |
we present the results of early observations for 130 error-boxes of gamma-ray bursts performed with the mobile astronomical system of telescope-robots (master) global network of robotic telescopes from moscow state university in fully automatic mode (2011-2017). among them, grb 130907a, grb 120811c, grb 110801a, grb 12... | early optical observations of gamma-ray bursts compared with their gamma- and x-ray characteristics using a master global network of robotic telescopes from lomonosov moscow state university |
the imaging quality of a telescope directly affects the reliability of astronomical research. through the monitoring and diagnosis of imaging quality, the cause of the deterioration of imaging quality can be found in time, which is essential for ensuring the peaking performance of the telescope and high-quality imaging... | intelligent monitoring and diagnosis of telescope image quality |
atmospheric turbulence is a fundamental problem in imaging through long slant ranges, horizontal-range paths, or uplooking astronomical cases through the atmosphere. an essential characterization of atmospheric turbulence is the point spread function (psf). turbulence images can be simulated to study basic questions, s... | synthesis of atmospheric turbulence point spread functions by sparse and redundant representations |
the dynamical states of molecular clouds may affect the properties of the stars they form. in the vicinity of the trifid nebula (d = 1180 ± 25 pc), the main star cluster (trifid main) lies within an expanding section of the molecular cloud; however, ~0.°3 to the north (trifid north), the cloud's velocity structure is m... | the effect of molecular cloud properties on the kinematics of stars formed in the trifid region |
we introduce a novel method for discerning optical telescope images of stars from those of galaxies using gaussian processes (gps). although applications of gps often struggle in high-dimensional data modalities such as optical image classification, we show that a low-dimensional embedding of images into a metric space... | star-galaxy image separation with computationally efficient gaussian process classification |
context. polarimetry is a powerful remote sensing tool to characterise solar system planets and, potentially, to detect and characterise exoplanets. the linear polarisation of a planet as a function of wavelength and phase angle is sensitive to the cloud and haze particle properties in planetary atmospheres, as well as... | a polarimetric investigation of jupiter: disk-resolved imaging polarimetry and spectropolarimetry |
this paper presents a 10 to 20 ghz bandwidth microwave polarimeter demonstrator, based on the implementation of a near-infra-red frequency up-conversion stage that allows both the optical correlation, when operating as a synthesized-image interferometer, and signal detection, when operating as a direct-image instrument... | a microwave polarimeter demonstrator for astronomy with near-infra-red up-conversion for optical correlation and detection |
modern giant segmented mirror telescopes (gsmts) such as the extremely large telescope, which is currently under construction, depend heavily on adaptive optics (ao) systems to correct for atmospheric distortions. however, a residual blur always remains in the astronomical images corrected by single conjugate ao (scao)... | off-axis point spread function reconstruction for single conjugate adaptive optics |
the oscillator strengths and integral cross sections (icss) of the schumann-runge continuum, and the longest band and second band of the oxygen molecule have wide applications in studies of the earth’s atmosphere and the stellar atmospheres, but there still exist apparent discrepancies among the available data. in this... | oscillator strengths and integral cross sections of the valence-shell excitations of the oxygen molecule studied by fast electron and inelastic x-ray scattering |
this text, now in its second edition, presents the mathematical background needed to design many optical combinations that are used in astronomical telescopes and cameras. it uses a novel approach to third-order aberration theory based on fermat's principle and the use of particular optical paths (called stigmatic path... | geometric optics: theory and design of astronomical optical systems using mathematica |
the optical oscillator strengths of the 3p54s and 3{{{p}}}54{{{s}}}\primeexcitations of argon are of crucial importance in determining the elemental abundance of argon from astronomical observations. substantial efforts have been made to determine the optical oscillator strengths of the 3p54s and 3{{{p}}}54{{{s}}}\prim... | the absolute optical oscillator strengths of the 3p54 s and 3{{\\rm{p}}}^{5}4{{\\rm{s}}}^{\\prime } excitations of argon measured by the dipole (γ, γ) method |
a stellar occultation by the large trans-neptunian object (90482) orcus was predicted to occur on 2017 march 07. observations were made at five sites in north and south america: the 0.6-m astronomical telescope of the university of stuttgart (atus) at sierra remote observatories, california; las cumbres observatory's 1... | a stellar occultation by vanth, a satellite of (90482) orcus |
we report the first detection of c2 {a}1{{{\pi }}}u-{x}1{{{σ }}}g+ (0,0) and cn {a}2{{{\pi }}}u-{x}2{{{σ }}}+ (0,0) absorption bands in the interstellar medium. the detection was made using the near-infrared (0.91-1.35 μm) high-resolution (r = 20,000 and 68,000) spectra of cygnus ob2 no. 12 collected with the winered s... | first detection of a-x (0,0) bands of interstellar c2 and cn |
typically, to analyze the data of the phase dependence of brightness atmosphereless celestial bodies one use some modification of the shadow mechanism involving the coherent mechanism. there are several modification of b.hapke [2] model divided into two groups by the number of unknown parameters: the first one with 4 p... | spectrophotometric properties of moon's and mars's surfaces exploration by shadow mechanism |
infrared avalanche photodiode (apd) arrays represent a panacea for many branches of astronomy by enabling extremely low-noise, high-speed, and even photon-counting measurements at near-infrared wavelengths. we recently demonstrated the use of an early engineering-grade infrared apd array that achieves a correlated doub... | high-speed imaging and wavefront sensing with an infrared avalanche photodiode array |
we present a catalogue of 348 galaxy clusters and groups with 0.2 < z < 1.2 selected in the 2.78 deg2 advanced large, homogeneous area medium band redshift astronomical (alhambra) survey. the high precision of our photometric redshifts, close to 1 per cent, and the wide spread of the seven alhambra pointings ensu... | galaxy clusters and groups in the alhambra survey |
context. the ophiuchus cluster, at a redshift z = 0.0296, is known from x-rays to be one of the most massive nearby clusters, but its optical properties have not been investigated in detail because of its very low galactic latitude.aims: we discuss the optical properties of the galaxies in the ophiuchus cluster, in par... | ophiuchus: an optical view of a very massive cluster of galaxies hidden behind the milky way ⋆ |
we present a new, fully generative model for constructing astronomical catalogs from optical telescope image sets. each pixel intensity is treated as a random variable with parameters that depend on the latent properties of stars and galaxies. these latent properties are themselves modeled as random. we compare two pro... | approximate inference for constructing astronomical catalogs from images |
phase resolved observations of planetary bodies allow us to understand the longitudinal and latitudinal variations that make each one unique. rotational variations have been detected in several types of astronomical bodies beyond those of planetary mass, including asteroids, brown dwarfs, and stars. unexpected rotation... | detection of rotational variability in floofy objects at optical wavelengths |
context. velocity measurements made from multiple-epoch astronomical images of evolving objects with optically thin continuum emission (e.g. as relativistic jets or expanding supernova shells) may be confused as a result of the overlap of semi-transparent features moving at different speeds.aims: multi-scale wavelet de... | detection of multiple velocity components in partially overlapping emitting regions |
context. most o-type stars and many b stars show unexplained cyclical variability in their spectral lines, i.e., modulation on the rotational timescale, but not strictly periodic. the variability occurs in the so-called discrete absorption components (dacs) that accelerate through the uv-wind line profiles and also in ... | multiple short-lived stellar prominences on o stars: the o6.5i(n)fp star λ cephei |
we have observed two of the six frontier fields galaxy clusters, macs j0416.1-2403 and abell 2744, using the gemini multi-conjugate adaptive optics system (gems) and the gemini south adaptive optics imager (gsaoi). with 0.″ 08-0.″ 10 fwhm our data are nearly diffraction-limited over a 100\prime\prime × 100\prime\prime ... | gemini frontier fields: wide-field adaptive optics ks-band imaging of the galaxy clusters macs j0416.1-2403 and abell 2744 |
context. we present integral field unit (ifu) observations with muse and deep imaging with fors of a dwarf galaxy recently formed within the giant collisional hi ring surrounding ngc 5291. this tidal dwarf galaxy (tdg) -like object has the characteristics of typical z = 1-2 gas-rich spiral galaxies: a high gas fraction... | ionization processes in a local analogue of distant clumpy galaxies: vlt muse ifu spectroscopy and fors deep images of the tdg ngc 5291n |
we describe the photometric calibration of the lunar-based ultraviolet telescope (lut), the first robotic astronomical telescope working on the lunar surface, for its first six months of operation on the lunar surface. two spectral datasets (set a and b) from near-ultraviolet (nuv) to the optical band were constructed ... | photometric calibration of the lunar-based ultraviolet telescope for its first six months of operation on the lunar surface |
light is the richest information retriever for most physical systems, particularly so for astronomy and cosmology, in which gravitation is of paramount importance, and also for solid state defects and metamaterials, in which some effects can be mimicked by non-euclidean or even non-riemannian geometries. thus, it is ex... | how does light move in a generic metric-affine background? |
nasa’s suborbital program provides an opportunity to conduct unique science experiments above earth’s atmosphere and is a pipeline for the technology and personnel essential to future space astrophysics, heliophysics, and atmospheric science missions. in this paper, we describe three astronomy payloads developed (or in... | the slice, chess, and sistine ultraviolet spectrographs: rocket-borne instrumentation supporting future astrophysics missions |
this paper presents a comprehensive site survey of the delingha site on the northern tibetan plateau from 2012 to 2014. in this campaign, we investigated 24 h continuous astronomical seeing, meteorological properties, and $c_{n}^{2}$ in the ground layer (gl). the results show that the median seeing is 3.46 arcsec durin... | astronomical seeing and ground-level optical turbulence at delingha observatory on the northern tibetan plateau |
we use observations with the infrared-optimized magellan adaptive optics (magao) system and clio camera in 3.9 μm light to place stringent mass constraints on possible undetected companions to sirius a. we suppress the light from sirius a by imaging it through a grating vector-apodizing phase plate coronagraph with a 1... | improved companion mass limits for sirius a with thermal infrared coronagraphy using a vector-apodizing phase plate and time-domain starlight-subtraction techniques |
we present an overview of a multiwavelength survey of the shapley supercluster (ssc; z ∼ 0.05) covering a contiguous area of 260 h^{-2}_{70} mpc2 including the supercluster core. the project main aim is to quantify the influence of cluster-scale mass assembly on galaxy evolution in one of the most massive structures in... | shapley supercluster survey: galaxy evolution from filaments to cluster cores |
in this work, we investigate the likelihood of association between real-time, neutrino alerts with teraelectronvolt to petaelectronvolt energy from icecube and optical counterparts in the form of core-collapse supernovae (cc sne). the optical follow-up of icecube alerts requires two main instrumental capabilities: (1) ... | a decam search for explosive optical transients associated with icecube neutrino alerts |
since a number of years our group is engaged in the design, construction and operation of instruments with very high time resolution in the optical band for applications to quantum astronomy and more conventional astrophysics. two instruments were built to perform photon counting with sub-nanosecond temporal accuracy. ... | intensity interferometry with aqueye+ and iqueye in asiago |
optical vortices are the electromagnetic analogue of fluid vortices studied in hydrodynamics. in both cases, the traveling wavefront, either made of light or fluid, is twisted like a corkscrew around its propagation axis—an analogy that also inspired the first proposition of the concept of optical vortices. even though... | recent twists in twisted light: a perspective on optical vortices from dielectric metasurfaces |
dome a in antarctica has been demonstrated to be the best site on earth for optical, infrared, and terahertz astronomical observations by more and more evidence, such as excellent free-atmosphere seeing, extremely low perceptible water vapor, low sky background, and continuous dark time, etc. in this paper, we present ... | astronomy from dome a in antarctica |
although the majority of herbig ae/be (haebe) stars are likely multiple systems, relatively few multiples have been identified. we aim to create a statistically significant survey of haebe multiplicity as a function of stellar mass, to shed light on mixed-mass star formation. two independent adaptive optics ir imaging ... | a survey of herbig ae/be multiplicity |
the determination of supermassive black hole (smbh) masses is the key to understanding the host galaxy build-up and the smbh mass assembly histories. the smbh masses of non-local quasars are frequently estimated via the single-epoch virial black-hole mass estimators, which may suffer from significant biases. here we de... | the mass distribution of quasars in optical time-domain surveys |
including millimeter-wave data in multiwavelength studies of the variability of active galactic nuclei (agn) can provide insights into agn physics that are not easily accessible at other wavelengths. we demonstrate in this work the potential of cosmic microwave background (cmb) telescopes to provide long-term, high-cad... | simultaneous millimeter-wave, gamma-ray, and optical monitoring of the blazar pks 2326-502 during a flaring state |
the classification of γ-ray-detected blazar candidates of uncertain type (bcu) is a relevant problem in extragalactic γ-ray astronomy. here, we report the optical spectroscopic characterization, using two 3-4 m class telescopes, telescopio nazionale galileo and devasthal optical telescope, of 27 bcus detected with the ... | optical spectroscopic characterization of fermi blazar candidates of uncertain type with tng and dot: first results |
the immense amount of time series data produced by astronomical surveys has called for the use of machine learning algorithms to discover and classify several million celestial sources. in the case of variable stars, supervised learning approaches have become commonplace. however, this needs a considerable collection o... | semi-supervised classification and clustering analysis for variable stars |
tidal disruption events (tdes) are highly energetic phenomena that occur when a star is tidally disrupted by the central massive black hole in a galaxy. fitting the observed x-ray spectra of tdes with a first-principles, general-relativistic slim-disk model for the emission from the inner accretion disk can constrain t... | a census of archival x-ray spectra for modeling tidal disruption events |
wayne state university's dan zowada memorial observatory is a fully robotic 0.5 m telescope and imaging system located under the dark skies of new mexico. the observatory is particularly suited to time domain astronomy: the observation of variable objects, such as tidal disruption events, supernovae, and active galacti... | wayne state university's dan zowada memorial observatory: characterization and pipeline of a 0.5 m robotic telescope |
the angular size of a star is a critical factor in determining its basic properties1. direct measurement of stellar angular diameters is difficult: at interstellar distances stars are generally too small to resolve by any individual imaging telescope. this fundamental limitation can be overcome by studying the diffract... | direct measurement of stellar angular diameters by the veritas cherenkov telescopes |
the use of artificial intelligence techniques has become widespread in many fields of science, due to their ability to learn from real data and adjust to complex models with ease. these techniques have landed in the field of adaptive optics, and are being used to correct distortions caused by atmospheric turbulence in ... | experience with artificial neural networks applied in multi-object adaptive optics |
we present an experimental study on our first generation of custom-developed arrayed waveguide gratings (awg) on silica platform for spectroscopic applications in near-infrared astronomy. we provide a comprehensive description of the design, numerical simulation and characterization of several awg devices aimed at spec... | design, simulation and characterization of integrated photonic spectrographs for astronomy: generation-i awg devices based on canonical layouts |
weak gravitational lensing (wl) is one of the most powerful techniques to learn about the dark sector of the universe. to extract the wl signal from astronomical observations, galaxy shapes must be measured and corrected for the point-spread function (psf) of the imaging system with extreme accuracy. future wl missions... | the effect of detector nonlinearity on wfirst psf profiles for weak gravitational lensing measurements |
aims: our objective is the optical and near-infrared spectroscopic characterisation of 2mass j0249-0557 c, a recently discovered young planetary mass companion to the β pictoris (~25 myr) member 2mass j0249-0557.methods: using the visible and infrared survey telescope for astronomy hemisphere survey and the two micron ... | strong hα emission in the young planetary mass companion 2mass j0249-0557 c |
laboratory results of the optical properties of vapor-deposited water ice, specifically the refractive index and extinction coefficient, are available mainly for a selective set of wavelengths and a limited number of deposition temperatures. experimental limitations are the main reason for the lack of broadband data, w... | refractive index and extinction coefficient of vapor-deposited water ice in the uv-vis range |
astronomical spectropolarimeters require high accuracy polarizers with large aperture and stringent uniformity requirements. in solar applications, wire grid polarizers are often used as performance is maintained under high heat loads and temperatures over 200°c. dkist is the nsf's new 4-m aperture solar telescope desi... | polarization modeling and predictions for dkist, part 8: calibration polarizer spatial variation impacts |
introduction of adaptive optics technology into astronomy and ophthalmology has made great contributions in these fields, allowing one to recover images blurred by atmospheric turbulence or aberrations of the eye. similar adaptive optics improvement in microscopic imaging is also of interest to researchers using variou... | holographic fluorescence microscopy with incoherent digital holographic adaptive optics |
we present the results from a detailed analysis of our high-resolution spectra and historical photometric observations of the semidetached eclipsing binary v392 ori with a δ scuti (δ sct) pulsating component. a total of 31 spectroscopic observations were carried out at both the bohyunsan optical astronomy observatory i... | time-series spectroscopy of the oscillating eclipsing algol system v392 orionis |
cherenkov emission of extensive air showers (eas) from cosmic gamma rays and cosmic-ray protons has been modelled. spectral density of such emission in the 240-700 nm band has been determined for 3 gev-10 tev primaries of both sorts. it has been shown that the ratio of eas cherenkov emission fluxes in the optical and u... | detection of uv radiation from extensive air showers: prospects for cherenkov gamma-ray astronomy |
spherex, a mission in nasa's medium explorer (midex) program recently selected for phase-a implementation, is an all-sky survey satellite that will produce a near-infrared spectrum for every 6 arcsecond pixel on the sky. spherex has a simple, high-heritage design with large optical throughput to maximize spectral mappi... | spherex: an all-sky nir spectral survey |
we present interferometric observations of six o-type stars that were made with the precision astronomical visible observations beam combiner at the center for high angular resolution astronomy (chara) array. the observations include multiple brackets for three targets, λ ori a, ζ oph, and 10 lac, but there are only pr... | angular sizes and effective temperatures of o-type stars from optical interferometry with the chara array |
we present hubble space telescope ultraviolet spectroscopy of the recurrent nova t pyxidis obtained more than five years after its 2011 outburst, indicating that the system might not have yet reached its deep quiescent state. the ultraviolet data exhibit a 20% decline in the continuum flux from the pre-outburst deep qu... | the long-term secular mass accretion rate of the recurrent nova t pyxidis |
data products from high spectral resolution astronomical polarimeters are often limited by fringes. fringes can skew derived magnetic field properties from spectropolarimetric data. fringe removal algorithms can also corrupt the data if the fringes and object signals are too similar. for some narrow-band imaging polari... | polarization modeling and predictions for dkist part 3: focal ratio and thermal dependencies of spectral polarization fringes and optic retardance |
this book presents the generalized multipole technique as a fast and powerful theoretical and computation tool to simulate light scattering by nonspherical particles. it also demonstrates the considerable potential of the method. in recent years, the concept has been applied in new fields, such as simulation of electro... | the generalized multipole technique for light scattering: recent developments |
an wide range, all-sky camera network is an effective infrastructure for the detection of atmospheric entries of natural (meteoroids) or artificial bodies (space debris). the meteorites orbits reconstruction by optical imaging (moroi) is an allsky network operated by the astronomical institute of the romanian academy. ... | meteorites orbits reconstruction by optical imaging (moroi) network |
a large fraction of accreting black hole and neutron star systems present clear evidence of the reprocessing of x-rays in the atmosphere of an optically thick accretion disk. the main hallmarks of x-ray reflection include fluorescent k-shell emission lines from iron (∼6.4-6.9 kev), the absorption iron k-edge (∼7-9 kev)... | accurate treatment of comptonization in x-ray illuminated accretion disks |
the herbig ae star hd 169142 is known to have a gaseous disk with a large inner hole, and also a photometrically variable inner dust component in the sub-astronomical-unit region. following up on our previous analysis, we further studied the temporal evolution of inner dust around hd 169142, which may provide informati... | variable warm dust around the herbig ae star hd 169142: birth of a ring? |
thanks to deep optical to near-ir imaging and spectroscopy, significant progress is made in characterizing the rest-frame uv to optical properties of galaxies in the early universe (z > 4. surveys with hubble, spitzer, and ground-based facilities (keck, subaru, and vlt) provide spectroscopic and photometric redshift... | panchromatic study of the first galaxies with large alma programs |
the esa gaia satellite scans the whole sky with a temporal sampling ranging from seconds and hours to months. each time a source passes within the gaia field of view, it moves over 10 charge coupled devices (ccds) in 45 s and a light curve with 4.5 s sampling (the crossing time per ccd) is registered. given that the 4.... | the fast transient sky with gaia |
context. luminous blue variables (lbvs) are rare massive stars with very high luminosity. they are characterized by strong photometric and spectroscopic variability related to transient eruptions. the mechanisms at the origin of these eruptions is not well known. in addition, their formation is still problematic and th... | luminous blue variables: an imaging perspective on their binarity and near environment |
the cherenkov telescope array (cta), is an international project for the next generation ground- based observatory for gamma-ray astronomy in the energy range from 20 gev to 300 tev. the sensitivity in the core energy range will be dominated by up to 40 medium-sized telescopes (msts). the msts, of davies-cotton type wi... | status of the medium-sized telescope for the cherenkov telescope array |
we present a keck/mosfire rest-optical composite spectrum of 16 typical gravitationally lensed star-forming dwarf galaxies at 1.7 ≲ z ≲ 2.6 (z mean = 2.30), all chosen independent of emission-line strength. these galaxies have a median stellar mass of $\mathrm{log}{({m}_{* }/{m}_{\odot })}_{\mathrm{med}}={8.29}_{-0.43}... | the direct-method oxygen abundance of typical dwarf galaxies at cosmic high noon |
the kepler mission has provided a wealth of data, revealing new insights in time-domain astronomy. however, kepler's single bandpass has limited studies to a single wavelength. in this work we build a data-driven, pixel-level model for the pixel response function (prf) of kepler targets, modeling the image data from th... | multiwavelength photometry derived from monochromatic kepler data |
aims: our objective is to identify analogues of gas giant planets, but located as companions at wide separations of very young stars. the main purpose is to characterise the binarity frequency and the properties of these substellar objects, and to elucidate their early evolutionary stages.methods: to identify these obj... | usco1621 b and usco1556 b: two wide companions at the deuterium-burning mass limit in upper scorpius |
theoretical stellar spectra rely on model stellar atmospheres computed based on our understanding of the physical laws at play in the stellar interiors. these models, coupled with atomic and molecular line databases, are used to generate theoretical stellar spectral libraries (ssls) comprising of stellar spectra over a... | stellar spectral interpolation using machine learning |
direct imaging of exoplanets represents a challenge for astronomical instrumentation due to the high-contrast ratio and small angular separation between the host star and the faint planet. multi-star systems pose additional challenges for coronagraphic instruments due to the diffraction and aberration leakage caused by... | techniques for high-contrast imaging in multi-star systems. ii. multi-star wavefront control |
context. we present the second public data release of the vista extension to auxiliary surveys (vexas), where we classify objects into stars, galaxies, and quasars based on an ensemble of machine learning algorithms.aims: the aim of vexas is to build the widest multi-wavelength catalogue, providing reference magnitudes... | vexas: vista extension to auxiliary surveys. data release 2: machine-learning based classification of sources in the southern hemisphere |
in any imaging survey, measuring accurately the astronomical background light is crucial to obtain good photometry. this paper introduces bkgnet, a deep neural network to predict the background and its associated error. bkgnet has been developed for data from the physics of the accelerating universe survey (paus), an i... | the pau survey: background light estimation with deep learning techniques |
understanding the origin of fe ii emission is important because it is crucial to construct the main sequence of active galactic nuclei (agns). despite several decades of observational and theoretical effort, the location of the optical iron emitting region and the mechanism responsible for the positive correlation betw... | an extraordinary response of iron emission to the central outburst in a tidal disruption event candidate |
the unusual extinction curves of sn 2010jl provide an excellent opportunity to investigate the properties of dust formed by core-collapse supernovae. by using a series of dust models with different compositions and grain size distributions, we fit the extinction curves of sn 2010jl and find that a silicate-graphite mix... | dust models for the extinction of type iin supernova sn 2010jl |
photometric pipelines struggle to estimate both the flux and flux uncertainty for stars in the presence of structured backgrounds such as filaments or clouds. however, it is exactly stars in these complex regions that are critical to understanding star formation and the structure of the interstellar medium. we develop ... | photometry on structured backgrounds: local pixel-wise infilling by regression |
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