abstract stringlengths 3 192k | title stringlengths 4 857 |
|---|---|
spectral shaping is critical to many fields of science. in astronomy for example, the detection of exoplanets via the doppler effect hinges on the ability to calibrate a high resolution spectrograph. laser frequency combs can be used for this, but the wildly varying intensity across the spectrum can make it impossible ... | flattening laser frequency comb spectra with a high dynamic range, broadband spectral shaper on-a-chip |
we present late-time optical follow-up observations of grb 171010a/sn 2017htp (z = 0.33) and low-luminosity grb 171205a/sn 2017iuk (z = 0.037) acquired using the 4k ×4k ccd imager mounted at the 3.6 m devasthal optical telescope (3.6 m dot) along with the prompt emission data analysis of these two interesting bursts. t... | tale of grb 171010a/sn 2017htp and grb 171205a/sn 2017iuk: magnetar origin? |
in recent years, the performance of scientific complementary metal oxide semiconductor (scmos) sensors has been improved significantly. compared with charge-coupled device sensors, scmos sensors have various advantages, making them potentially better devices for optical and x-ray detection, especially in time-domain as... | x-ray performance of a customized large-format scientific cmos detector |
the direct imaging of an earth-like exoplanet will require sub-nanometric wave-front control across large light-collecting apertures to reject host starlight and detect the faint planetary signal. current adaptive optics systems, which use wave-front sensors that reimage the telescope pupil, face two challenges that pr... | real-time experimental demonstrations of a photonic lantern wave-front sensor |
we study accretion disk emission from eight seyfert 1-1.5 active galactic nuclei (agn) using far-ultraviolet (fuv) (1300-1800 å) slitless grating spectra acquired with astrosat/uvit. we correct for the galactic and intrinsic extinction, contamination from the host galaxies, narrow and broad-line regions, fe ii emission... | far-ultraviolet spectroscopy of active galactic nuclei with astrosat/uvit |
raman fiber laser (rfl) has been widely adopted in astronomy, optical sensing, imaging, and communication due to its unique advantages of flexible wavelength and broadband gain spectrum. conventional rfls are generally based on silica fiber. here, we demonstrate that the phosphosilicate fiber has a broader raman gain s... | broadband tunable raman fiber laser with monochromatic pump |
the ability of an interferometer to characterize the spatial information of a light beam is often limited by the temporal profile of the beam, with femtosecond pulse characterization being particularly challenging. in this study, we developed a simple, stable, controllable shearing and vectorial phase-shifting wedged r... | complete characterization of ultrashort optical pulses with a phase-shifting wedged reversal shearing interferometer |
a global site selection for astronomy was performed with 1 km spatial resolution (∼1 gigapixel in size) using long-term and up-to-date datasets to classify the entire terrestrial surface of the earth. satellite instruments are used to get the following datasets of geographical information system (gis) layers: cloud cov... | global site selection for astronomy |
we report the gas-phase optical detection of si2c near 390 nm and the first experimental investigation of the rovibrational structure of its 1a1 ground electronic state using mass-resolved and fluorescence spectroscopy and variational calculations performed on a high-level ab initio potential. from this joint study, it... | communication: the ground electronic state of si2c: rovibrational level structure, quantum monodromy, and astrophysical implications |
we present an elemental-abundance analysis, in the near-ultraviolet (nuv) spectral range, for the bright carbon-enhanced metal-poor (cemp) stars hd 196944 (v=8.40, [fe/h] = -2.41) and hd 201626 (v=8.16, [fe/h] = -1.51), based on data acquired with the space telescope imaging spectrograph (stis) on the hubble space tele... | hubble space telescope near-ultraviolet spectroscopy of bright cemp-s stars |
we present the technical specifications and first results of the esa-funded, lunar monitoring project "neliota" (neo lunar impacts and optical transients) at the national observatory of athens, which aims to determine the size-frequency distribution of small near-earth objects (neos) via detection of impact flashes on ... | neliota: the wide-field, high-cadence, lunar monitoring system at the prime focus of the kryoneri telescope |
the propagation of γ rays over very large distances provides new insights on the intergalactic medium and on fundamental physics. on their path to the earth, γ rays can annihilate with diffuse infrared or optical photons of the intergalactic medium, producing e+e- pairs. the density of these photons is poorly determine... | gamma rays as probes of the universe |
aims: with its high sensitivity, the pyramid wavefront sensor (pywfs) is becoming an advantageous sensor for astronomical adaptive optics (ao) systems. however, this sensor exhibits significant non-linear behaviours leading to challenging ao control issues.methods: in order to mitigate these effects, we propose to use ... | focal-plane-assisted pyramid wavefront sensor: enabling frame-by-frame optical gain tracking |
as the sensitivity of gravitational wave (gw) instruments improves and new networks start operating, hundreds of merging stellar-mass black holes (sbhs) and intermediate-mass black holes (imbhs) are expected to be observed in the next few years. the origin and distribution of sbh and imbh binaries in various dynamical ... | calibrating the binary black hole population in nuclear star clusters through tidal disruption events |
ring resonators provide a means of filtering specific wavelengths from a waveguide, and optionally dropping the filtered wavelengths into a second waveguide. both of these features are potentially useful for astronomical instruments. in this paper we focus on their use as notch filters to remove the signal from atmosph... | photonic ring resonator filters for astronomical oh suppression |
the nitrogen-to-oxygen (n/o) abundance ratio is an important diagnostic of galaxy evolution because the ratio is closely tied to the growth of metallicity and the star formation history in galaxies. estimates for the n/o are traditionally made with optical lines that could suffer from extinction and excitation effects,... | far-infrared line diagnostics: improving n/o abundance estimates for dusty galaxies |
future microcalorimeter x-ray observations will resolve spectral features in unmatched detail. understanding of line formation processes in x-rays deserves much attention. the purpose of this paper is to discuss such processes in the presence of a photoionizing source. line formation processes in one- and two-electron ... | x-ray spectroscopy in the microcalorimeter era. iii. line formation under case a, case b, case c, and case d in h- and he-like iron for a photoionized cloud |
we present results from the large adaptive optics survey for substellar objects, where the goal is to directly image new substellar companions (<70 mjup) at wide orbital separations (≳50 au) around young (≲300 myr), nearby (<100 pc), low-mass (≈0.1-0.8 ${m}_{\odot }$ ) stars. we report on 427 young stars imaged i... | large adaptive optics survey for substellar objects around young, nearby, low-mass stars with robo-ao |
as one of the most interesting seyfert 1 galaxies, pg 2130+099 has been the target of several reverberation mapping (rm) campaigns over the years. however, its measured broad hβ line responses have been inconsistent, with time lags of ∼200 days, ∼25 days, and ∼10 days being reported for different epochs while its optic... | broad-line region of the quasar pg 2130+099 from a two-year reverberation mapping campaign with high cadence |
we derive a distance of d = 16.6 ± 0.3 mpc (μ = 31.10 ± 0.04 mag) to the archetypal narrow-line seyfert 1 galaxy ngc 4051 based on cepheid period-luminosity relations and new hubble space telescope multiband imaging. we identify 419 cepheid candidates and estimate the distance at both optical and near-infrared waveleng... | the cepheid distance to the narrow-line seyfert 1 galaxy ngc 4051 |
relativistic magnetic reconnection is a potential particle acceleration mechanism for high-frequency bl lac objects (hbls). the imaging x-ray polarimetry explorer (ixpe) scheduled to launch in 2021 has the capability to probe the evolution of magnetic field in hbls, examining the magnetic reconnection scenario for the ... | first-principles prediction of x-ray polarization from magnetic reconnection in high-frequency bl lacertae objects |
in the framework of the standard model extension (sme), we present improved constraints on anisotropic lorentz invariance and charge-parity-time (c p t ) violation by searching for astrophysical signals of cosmic vacuum birefringence with broadband optical polarimetry of high redshift astronomical sources, including ac... | improved constraints on anisotropic birefringent lorentz invariance and c p t violation from broadband optical polarimetry of high redshift galaxies |
we have performed a high-resolution 4-13 μm spectral survey of the hot molecular gas associated with the massive protostars afgl 2591 and afgl 2136. here we present the results of the analysis of the ν 2 band of h2o, detected with the echelon cross echelle spectrograph on board the stratospheric observatory for infrare... | infrared h2o absorption in massive protostars at high spectral resolution: full spectral survey results of afgl 2591 and afgl 2136 |
context. b[e] supergiants are massive post-main-sequence stars, surrounded by a complex circumstellar environment where molecules and dust can survive. the shape in which the material is distributed around these objects and its dynamics as well as the mechanisms that give rise to these structures are not well understoo... | resolving the clumpy circumstellar environment of the b[e] supergiant lha 120-s 35 |
we present detailed chemical abundances of three new bright (v ∼ 11), extremely metal-poor ([fe/h] ∼ -3.0), r-process-enhanced halo red giants based on high-resolution, high-s/n magellan/mike spectra. we measured abundances for 20-25 neutron-capture elements in each of our stars. j1432-4125 is among the most r-process-... | the r-process alliance: chemical abundances for a trio of r-process-enhanced stars—one strong, one moderate, and one mild |
we consider the standard problem of observational astronomy, i.e., the observations of light emission from a distant region of spacetime in general relativity. the goal is to describe the changes between the measurements of the light performed by a sample of observers slightly displaced with respect to each other and m... | geometric optics in general relativity using bilocal operators |
the second (o2) observational campaign of gravitational waves (gws) organized by the ligo/virgo collaborations has led to several breakthroughs such as the detection of gw signals from merger systems involving black holes or neutrons stars. during o2, 14 gw alerts were sent to the astronomical community with sky region... | the mini-gwac optical follow-up of gravitational wave alerts - results from the o2 campaign and prospects for the upcoming o3 run |
black holes in general relativity are characterized by their trapping horizon, a one-way membrane that can be crossed only inwards. the existence of trapping horizons in astrophysical black holes can be tested observationally using a reductio ad absurdum argument, replacing black holes by horizonless configurations wit... | seeking observational evidence for the formation of trapping horizons in astrophysical black holes |
we explore the properties of ionized gas in the nuclear and circumnuclear environment of the narrow-line seyfert 1 galaxy ngc 4051 using spectroscopic and imaging observations from the hubble space telescope (hst) and apache point observatory's arc 3.5 m telescope. we identify an unresolved moderate-density intermediat... | radiative driving of the agn outflows in the narrow-line seyfert 1 galaxy ngc 4051 |
we present optical and near-infrared adaptive optics (ao) imaging and spectroscopy of 13 ultracool (>m6) companions to late-type stars (k7-m4.5), most of which have recently been identified as candidate members of nearby young moving groups (ymgs; 8-120 myr) in the literature. three of these are new companions ident... | planets around low-mass stars (palms). v. age-dating low-mass companions to members and interlopers of young moving groups |
we report the discovery of pulsations in three mixed-atmosphere, extremely low-mass white dwarf (elm wd, m ≤slant 0.3 m ⊙) precursors. following the recent discoveries of pulsations in both elm and pre-elm wds, we targeted pre-elm wds with mixed h/he atmospheres with high-speed photometry. we find significant optical v... | discovery of three pulsating, mixed-atmosphere, extremely low-mass white dwarf precursors |
aqueye+ is a new ultrafast optical single photon counter, based on single photon avalanche photodiodes (spad) and a 4- fold split-pupil concept. it is a completely revisited version of its predecessor, aqueye, successfully mounted at the 182 cm copernicus telescope in asiago. here we will present the new technological ... | aqueye+: a new ultrafast single photon counter for optical high time resolution astrophysics |
we present a new optical (400-950 nm) transmission spectrum of the hot jupiter wasp-31b (m = 0.48 mj; r = 1.54 rj; p = 3.41 days), obtained by combining four transit observations. these transits were observed with imacs on the magellan baade telescope at las campanas observatory as part of the access project. we invest... | access: confirmation of no potassium in the atmosphere of wasp-31b |
ground-based optical telescopes are seriously affected by atmospheric turbulence induced aberrations. understanding properties of these aberrations is important both for instrument design and image restoration method development. because the point-spread function can reflect performance of the whole optic system, it is... | psf-net: a nonparametric point-spread function model for ground-based optical telescopes |
wide-field astronomical surveys are often affected by the presence of undesirable reflections (often known as "ghosting artifacts" or "ghosts") and scattered-light artifacts. the identification and mitigation of these artifacts is important for rigorous astronomical analyses of faint and low-surface-brightness systems.... | deepghostbusters: using mask r-cnn to detect and mask ghosting and scattered-light artifacts from optical survey images |
we present observations of a solar magnetic network region in the millimeter continuum with the atacama large millimeter/submillimeter array (alma) and in the ca 8542 and na 5896 å spectral lines with the interferometric bidimensional spectrometer (ibis). our goal is to compare the measurement of local gas temperatures... | evaluating non-lte spectral inversions with alma and ibis |
large-scale astronomical surveys have the potential to capture data on large numbers of strongly gravitationally lensed supernovae (lsne). to facilitate timely analysis and spectroscopic follow-up before the supernova fades, an lsn needs to be identified soon after it begins. to quickly identify lsne in optical survey ... | deepzipper: a novel deep-learning architecture for lensed supernovae identification |
in this letter, we report the discovery of an ultraluminous fast-evolving transient in rest-frame uv wavelengths, musses2020j, soon after its occurrence by using the hyper suprime-cam (hsc) mounted on the 8.2 m subaru telescope. the rise time of about 5 days with an extremely high uv peak luminosity shares similarities... | musses2020j: the earliest discovery of a fast blue ultraluminous transient at redshift 1.063 |
the far-ultraviolet (fuv) emission of classical t tauri stars (cttss) is known to play an important role in protoplanetary disk dispersal and giant planet formation, yet the role played by protostellar flares in these processes is largely unknown. we use nearby star-forming regions as laboratories to probe the fuv flar... | far-ultraviolet flares on accreting protostars: weak and classical t tauri stellar pair analysis |
absorption and emission lines of the iron-peak species fe ii are prominent in the infrared, optical, and ultraviolet spectra of a myriad of astrophysical sources, requiring extensive and highly reliable sets of atomic structure and collisional data for an accurate quantitative analysis. however, comparisons among exist... | towards converged electron-impact excitation calculations of low-lying transitions in fe ii |
continuous measurements of the potential gradient are being recorded at the casleo astronomical observatory near to the andes mountain of argentina, since 2010 (latitude: 31°47.88‧s, longitude: 69°17.7‧w, altitude: 2552 masl). this study aims to use the potential gradient diurnal variation in fair weather conditions, w... | analysis of long-term potential gradient variations measured in the argentinian andes |
the persistent increase of artificial light emissions is causing a progressive brightening of the night sky in most regions of the world. this process is a threat for the long-term sustainability of the scientific and educational activity of ground-based astronomical observatories operating in the optical range. huge i... | a linear systems approach to protect the night sky: implications for current and future regulations |
context. the uv bump observed in the interstellar medium extinction curve of galaxies has been assigned to π → π⋆ transitions within the sp2 conjugated network of carbon grains. these grains are commonly thought to be graphitic particles or polycyclic aromatic hydrocarbons. however, questions are still open regarding t... | quantum modeling of the optical spectra of carbon cluster structural families and relation to the interstellar extinction uv bump |
we describe techniques developed to optimize beam pointing control for a cubesat laser downlink demonstration mission being developed at the mit space telecommunications, astronomy, and radiation laboratory. to fine-point its downlink beam, the mission utilizes an uplink beacon signal at 976 nm captured by an on-board ... | on-orbit beam pointing calibration for nanosatellite laser communications |
sphere is the high-contrast exoplanet imager and spectrograph installed at the unit telescope 3 of the very large telescope. after more than two years of regular operations, we analyse statistically the performance of the adaptive optics system and its dependence on the atmospheric conditions above the paranal observat... | performance of the extreme-ao instrument vlt/sphere and dependence on the atmospheric conditions |
neutral fe lines in metal-poor stars yield conflicting abundances depending on whether and how deviations from local thermodynamic equilibrium (lte) are considered. we have collected new high-resolution and high signal-to-noise ultraviolet (uv) spectra of three warm dwarf stars with [fe/h] ≈ -2.9 with the space telesco... | consistent iron abundances derived from neutral and singly ionized iron lines in ultraviolet and optical spectra of six warm metal-poor stars |
in a previous article we suggested a method to overcome the diffraction limit behind a telescope. we refer to theory and recent numerical simulations, and test whether it is indeed possible to use photon amplification to enhance the angular resolution of a telescope or a microscope beyond the diffraction limit. an esse... | beyond the diffraction limit via optical amplification |
we develop a method to estimate the dust attenuation curve of galaxies from full optical spectral fitting. motivated by previous studies, we separate the small-scale features from the large-scale spectral shape, by performing a moving average method to both the observed spectrum and the simple stellar population (ssp) ... | estimating dust attenuation from galactic spectra. i. methodology and tests |
we discuss the importance of fe23+ in determining the line intensities of the fe xxv kα complex in an optically thick cloud, and investigate resonant auger destruction (rad) with cloudy. although initially motivated by the perseus cluster, our calculations are extended to the wide range of column densities encountered ... | x-ray spectroscopy in the microcalorimeter era. i. effects of fe xxiv resonant auger destruction on fe xxv kα spectra |
with bolometric luminosities exceeding 1048 erg s-1, powerful jets, and supermassive black holes at their center, mev blazars are some of the most extreme sources in the universe. recently, the fermi-large area telescope detected five new γ-ray emitting mev blazars beyond redshift z = 3.1. with the goal of precisely ch... | nustar perspective on high-redshift mev blazars |
the prime kepler mission revealed that small planets (<4 {r}\oplus ) are common, especially around low-mass m dwarfs. k2, the repurposed kepler mission, continues this exploration of small planets around small stars. here we combine k2 photometry with spectroscopy, adaptive optics imaging, and archival survey images... | two small temperate planets transiting nearby m dwarfs in k2 campaigns 0 and 1 |
context. optical long baseline interferometry is a unique way to study astronomical objects at milli-arcsecond resolutions not attainable with current single-dish telescopes. yet, the significance of its scientfic return strongly depends on a dense coverage of the uv-plane and a highly stable transfer function of the i... | integrated optics prototype beam combiner for long baseline interferometry in the l and m bands |
we consider the mathematical background of the wavefront sensor type that is widely used in adaptive optics systems for astronomy, microscopy, and ophthalmology. the theoretical analysis of the pyramid sensor forward operators presented in this paper is aimed at a subsequent development of fast and stable algorithms fo... | real-time adaptive optics with pyramid wavefront sensors: part i. a theoretical analysis of the pyramid sensor model |
we present an anomaly detection method using wasserstein generative adversarial networks (wgans) on optical galaxy images from the wide-field survey conducted with the hyper suprime-cam (hsc) on the subaru telescope in hawai'i. the wgan is trained on the entire sample, and learns to generate realistic hsc-like images t... | anomaly detection in astronomical images with generative adversarial networks |
kilonovae are approximately thermal transients, produced by the mergers of binary neutron stars (bnss) and neutron star (ns)-black hole binaries. as the optical counterpart of the gravitational-wave event gw170817, at2017gfo is the first kilonova detected with smoking-gun evidence. its observation offers vital informat... | target-of-opportunity observation detectability of kilonovae with wfst |
we present extremely deep hubble space telescope (hst) wide field camera 3 (wfc3) observations of the muse ultra deep field. this unique region of the sky contains two quasars at z ≈ 3.22 that are separated by only ~500 kpc, providing a stereoscopic view of gas and galaxies in emission and absorption across ~10 billion... | the muse ultra deep field (mudf). iii. hubble space telescope wfc3 grism spectroscopy and imaging |
the wide-field infrared transient explorer (winter) is a new infrared time-domain survey instrument which will be deployed on a dedicated 1 meter robotic telescope at the palomar observatory. winter will perform a seeing-limited time domain survey of the infrared (ir) sky, with a particular emphasis on identifying r -p... | the wide-field infrared transient explorer (winter) |
astrophotonics is the application of photonic technologies to channel, manipulate, and disperse light from one or more telescopes to achieve scientific objectives in astronomy in an efficient and cost-effective way. utilizing photonic advantage for astronomical spectroscopy is a promising approach to miniaturizing the ... | astrophotonic spectrographs |
photonic integrated circuits (pic) are best known for their important role in the telecommunication sector, e.g. high speed communication devices in data centers. however, pic also hold the promise for innovation in sectors like life science, medicine, sensing, automotive etc. the past two decades have seen efforts of ... | astrophotonics: photonic integrated circuits for astronomical instrumentation |
we present the discovery of ztf 21aaoryiz/sn 2021fcg-an extremely low luminosity type iax supernova. sn 2021fcg was discovered by the zwicky transient facility in the star-forming galaxy ic0512 at a distance of ≈27 mpc. it reached a peak absolute magnitude of mr = -12.66 ± 0.20 mag, making it the least luminous thermon... | faintest of them all: ztf 21aaoryiz/sn 2021fcg-discovery of an extremely low luminosity type iax supernova |
we present uv and lyα radial surface brightness (sb) profiles of lyα emitters (laes) at z = 2.84 detected with the hyper suprime-cam on the subaru telescope. the depth of our data, together with the wide-field coverage including a protocluster, enable us to study the dependence of lyα halos (lahs) on various galaxy pro... | uv and lyα halos of lyα emitters across environments at z = 2.84 |
india's largest size 3.6 meter devashal optical telescope (dot) was commissioned in the year 2016, though the idea of building it germinated way back in the year 1976. this article provides research accounts as well as glimpses of its nearly four decades of journey. after a decade of site surveys, location of devasthal... | the 3.6 meter devasthal optical telescope: from inception to realisation |
recent models for the inner structures of active galactic nuclei (agns) advocate the presence of a radiatively accelerated dusty outflow launched from the outer regions of the accretion disk. here, we present the first near-ir variable (rms) spectrum for the high-luminosity nearby agn mrk 876. we find that it tracks th... | a complex dust morphology in the high-luminosity agn mrk 876 |
we report on new x-ray and optical observations of psr j2030+4415, a gamma-ray pulsar with an hα bow shock. these data reveal the velocity structure of the bow shock apex and resolve unusual x-ray structure in its interior. in addition the system displays a very long, thin filament, extending at least 5' at ∼130° to th... | psr j2030+4415's remarkable bow shock, pwn, and filament |
we describe the properties of mini-megatortora (mmt-9) nine-channel wide-field optical sky monitoring system with subsecond temporal resolution. this instrument can observe sky areas as large as 900 deg2, perform photometry in three filters close to johnson bv r system and polarimetry of selected objects or areas with ... | wide-field optical monitoring with mini-megatortora (mmt-9) multichannel high temporal resolution telescope |
weather has a critical impact on observations at optical and infrared wavelengths, and is a key factor in assessing the performance and productivity of future facilities. as a reference for comparison, we present an analysis of cloud cover, 200-hpa wind speed, precipitable water vapour, vertical wind velocity, and aero... | weather at selected astronomical sites - an overview of five atmospheric parameters |
context. one of the key noise sources that currently limits high-contrast imaging observations for exoplanet detection is quasi-static speckles. quasi-static speckles originate from slowly evolving non-common path aberrations (ncpa). these ncpa are related to the different optics encountered in the wavefront sensing pa... | first on-sky demonstration of spatial linear dark field control with the vector-apodizing phase plate at subaru/scexao |
in this paper, we analyze a machine-learning-based non-iterative phase retrieval method. phase retrieval and its applications have been attractive research topics in optics and photonics, for example, in biomedical imaging, astronomical imaging, and so on. most conventional phase retrieval methods have used iterative p... | analysis of non-iterative phase retrieval based on machine learning |
recent developments at the national institute of standards and technology's facility for spectral irradiance and radiance responsivity calibrations using uniform sources (sircus) are presented. the facility is predicated on the use of broadly tunable narrow-band lasers as light sources in two key radiometric calibratio... | invited article: advances in tunable laser-based radiometric calibration applications at the national institute of standards and technology, usa |
photometric multi-band follow up of sn 2023ixf in m101 from inaf - brera astronomical observatory, italy | optical multi-band follow-up of sn 2023ixf |
cloud segmentation plays a very important role in astronomical observatory site selection. at present, few researchers segment cloud in nocturnal all-sky imager (asi) images. this paper proposes a new automatic cloud segmentation algorithm that utilizes the advantages of deep-learning fully convolutional networks (fcns... | diurnal and nocturnal cloud segmentation of all-sky imager (asi) images using enhancement fully convolutional networks |
recent advances in time-domain astronomy have led to fresh observational insights into intermediate polars, a subtype of magnetic cataclysmic variables generally accreting via a partial accretion disc. these new discoveries include detections of superhumps, low states, and outbursts. however, these studies have largely... | the orbital period versus absolute magnitude relationship of intermediate polars: implications for low states and outbursts |
finding high-redshift (z ≫ 4) dusty star-forming galaxies is extremely challenging. it has recently been suggested that millimeter selections may be the best approach since the negative k-correction makes galaxies at a given far-infrared luminosity brighter at z ≳ 4 than those at z = 2-3. here we analyze this issue usi... | 2 mm observations and the search for high-redshift dusty star-forming galaxies |
at paranal observatory, the least predictable parameter affecting the short-term scheduling of astronomical observations is the optical turbulence, especially the seeing, coherence time and ground layer fraction. these are critical variables driving the performance of the instruments of the very large telescope (vlt), ... | nowcasting the turbulence at the paranal observatory |
we present a submillimeter continuum survey ("scuba2 high redshift bright quasar survey," hereafter sherry) of 54 high-redshift quasars at 5.6 < z < 6.9 with quasar bolometric luminosities in the range of (0.2-5) × 1014 l⊙, using the submillimetre common-user bolometer array-2 (scuba2) on the james clerk maxwell ... | scuba2 high redshift bright quasar survey: far-infrared properties and weak-line features |
hot subdwarf stars of spectral types o and b represent a poorly understood phase in the evolution of low-mass stars, in particular of close compact binaries. a variety of phenomena are observed, which make them important tools for several astronomical disciplines. for instance, the richness of oscillations of many subd... | heavy-metal enrichment of intermediate he-sdob stars: the pulsators feige 46 and ls iv-14°116 revisited |
we present a far-uv (fuv) study of the star-forming complexes (sfcs) in three nearby galaxies using the ultraviolet imaging telescope. the galaxies are close to face-on and show significant outer disk star formation. two of them are isolated (ngc 628 and ngc 6946), and one is interacting with distant companions (ngc 54... | comparing the inner and outer star-forming complexes in the nearby spiral galaxies ngc 628, ngc 5457, and ngc 6946 using uvit observations |
context. determining photometric redshifts (photo-zs) of extragalactic sources to a high accuracy is paramount to measure distances in wide-field cosmological experiments. with only photometric information at hand, photo-zs are prone to systematic uncertainties in the intervening extinction and the unknown underlying s... | mixture models for photometric redshifts |
detection of gravitational waves (gws) from neutron star-black hole (nsbh) standard sirens provides local measurements of the hubble constant (h 0), regardless of the detection of an electromagnetic (em) counterpart, given that matter effects can be exploited to break the redshift degeneracy of the gw waveforms. the di... | measuring the hubble constant with dark neutron star-black hole mergers |
ground-based optical astronomy necessarily involves sensing the light of astronomical objects along with the contributions of many natural sources ranging from the earth's atmosphere to cosmological light. in addition, astronomers have long contended with artificial light pollution, which further adds to the `backgroun... | night sky brightness measurement, quality assessment and monitoring |
euso-balloon is a pathfinder for jem-euso, the extreme universe space observatory which is to be hosted on-board the international space station. as jem-euso is designed to observe ultra-high energy cosmic rays (uhecr)-induced extensive air showers (eas) by detecting their ultraviolet light tracks "from above", euso-ba... | the euso-balloon pathfinder |
the direct imaging of exoplanet is a leading field of today's astronomy. the photons coming from the planet carry precious information on the chemical composition of its atmosphere. the second-generation instrument, spectro-polarimetric high contrast exoplanet research (sphere), dedicated to detection, photometry and s... | saxo: the extreme adaptive optics system of sphere (i) system overview and global laboratory performance |
the article is aimed at presenting a semi-empirical model coded and computed in the programming language python, which utilizes data gathered with a standard biaxial elastic lidar platform in order to calculate the altitude profiles of the structure coefficients of the atmospheric refraction index cn2(z) and other asso... | a turbulence-oriented approach to retrieve various atmospheric parameters using advanced lidar data processing techniques |
we present a comprehensive survey of diffuse interstellar bands (dibs) in 0.91-1.32 μm with the newly developed near-infrared (nir) spectrograph winered mounted on the araki 1.3 m telescope in japan. we obtained high-resolution (r = 28, 300) spectra of 25 early-type stars with color excesses of 0.07 < e(b - v) < ... | near-infrared diffuse interstellar bands in 0.91-1.32 μm |
one of the essential prerequisites for detection of earth-like extra-solar planets or direct measurements of the cosmological expansion is the accurate and precise wavelength calibration of astronomical spectrometers. it has already been realized that the large number of exactly known optical frequencies provided by la... | a microphotonic astrocomb |
we present measurements of the second-order spatial coherence function of thermal light sources using hanbury-brown and twiss interferometry with a digital correlator. we demonstrate that intensity fluctuations between orthogonal polarizations, or at detector separations greater than the spatial coherence length of the... | development of a digital astronomical intensity interferometer: laboratory results with thermal light |
for quantum communications, the use of earth-orbiting satellites to extend distances has gained significant attention in recent years, exemplified in particular by the launch of the micius satellite in 2016. the performance of applied protocols such as quantum key distribution (qkd) depends significantly on the transmi... | adaptive optics benefit for quantum key distribution uplink from ground to a satellite |
context. optical and infrared spatially unresolved multi-epoch observations have revealed the variability of pre-main sequence stars and/or their environment. moreover, structures in orbital motion around the central star, resulting from planet-disk interaction, are predicted to cause temporal variations in the brightn... | interferometric study on the temporal variability of the brightness distributions of protoplanetary disks |
context. as a fragile element, lithium is a sensitive probe of physical processes occurring in stellar interiors.aims: we aim to investigate the relationship between lithium abundance and rotation rate in low-mass members of the newly discovered 125 myr-old psc-eri stellar stream.methods: we obtained high-resolution op... | lithium-rotation connection in the newly discovered young stellar stream psc-eri (meingast 1) |
intensified charge coupled device (iccd) cameras are widely used in various applications such as microscopy, astronomy, spectroscopy. often they are used as single-photon detectors, with thresholding being an essential part of the readout. in this paper, we measure the quantum efficiency of an iccd camera in the single... | autonomous absolute calibration of an iccd camera in single-photon detection regime |
we present models of the inner region of the circumstellar disk of ry tau that aim to explain our near-infrared (k-band: 2.1 μm) interferometric observations, while remaining consistent with the optical to near-infrared portions of the spectral energy distribution. our submilliarcsecond-resolution chara array observati... | the inner disk of ry tau: evidence of stellar occultation by the disk atmosphere at the sublimation rim from k-band continuum interferometry |
context. systematic observations of magnetic field strength and polarity in sunspots began at mount wilson observatory (mwo), usa in early 1917. except for a few brief interruptions, this historical dataset has continued until the present.aims: sunspot field strength and polarity observations are critical in our projec... | reconstructing solar magnetic fields from historical observations. v. sunspot magnetic field measurements at mount wilson observatory |
we used optical images acquired with the wide field camera of the advanced camera for surveys on board the hubble space telescope and near-infrared data from gemini multi-conjugate adaptive optics system (gems)/gemini south adaptive optics imager (gsaoi) to construct a high-resolution extinction map in the direction of... | high-resolution extinction map in the direction of the strongly obscured bulge fossil fragment liller 1 |
gravitational wave (gw) events detectable by ligo and virgo have several possible progenitors, including black hole mergers, neutron star mergers, black hole-neutron star mergers, supernovae, and cosmic string cusps. a subset of gw events is expected to produce electromagnetic (em) emission that, once detected, will pr... | optical follow-up of gravitational wave triggers with decam during the first two ligo/virgo observing runs |
the diffuse, unresolved sky provides most of the photons that the hubble space telescope (hst) receives, yet remains poorly understood. the hst archival legacy program skysurf aims to measure the 0.2-1.6 μm sky surface brightness (sky-sb) from over 140,000 hst images. we describe a sky-sb measurement algorithm designed... | skysurf-4: panchromatic hubble space telescope all-sky surface-brightness measurement methods and results |
infrared interferometry has led to a paradigm shift in our understanding of the dusty structure in the central parsecs of active galactic nuclei (agns). the dust is now thought to comprise a hot (∼1000 k) equatorial disk, some of which is blown into a cooler (∼300 k) polar dusty wind by radiation pressure. in this pape... | resolving the hot dust disk of eso323-g77 |
optical astronomical images are strongly affected by the point spread function (psf) of the optical system and the atmosphere (seeing) which blurs the observed image. the amount of blurring depends both on the observed band, and on the atmospheric conditions during observation. a typical astronomical image will likely ... | neural network based point spread function deconvolution for astronomical applications |
in order to assess the multiplicity statistics of stars across spectral types and populations in a volume-limited sample, we censused nearby stars for companions with robo-ao. we report on observations of 1157 stars of all spectral types within 25 pc with decl. >-13° searching for tight companions. we detected 154 c... | an adaptive optics census of companions to northern stars within 25 pc with robo-ao |
ground-based optical long-baseline interferometry has the power to measure the orbits of close binary systems at ∼10 μas precision. this precision makes it possible to detect "wobbles" in the binary motion due to the gravitational pull from additional short-period companions. we started the arrangement for micro-arcsec... | armada. i. triple companions detected in b-type binaries α del and ν gem |
the helioglow is the fluorescence of interstellar atoms inside the heliosphere, where they are excited by the solar euv emission. so far, the helioglow of interstellar h and he has been detected. the helioglow features a characteristic distribution in the sky, which can be used to derive the properties of both interste... | wawhelioglow: a model of the heliospheric backscatter glow. i. model definition |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.