A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2018; you can also visit the original URL.
The file type is application/pdf.
Filters
Robust Calibration of Radio Interferometers in Non-Gaussian Environment
2017
IEEE Transactions on Signal Processing
Preserved Fulltext
Other Versions
Nevertheless, observations in the context of radio astronomy are known to be affected by the presence of outliers which are due to several causes, e.g., weak non-calibrator sources or man made radio frequency ...
Based on this modeling, a robust calibration algorithm is presented in this paper. ...
In [35] , theoretical and experimental analyses have been conducted in order to demonstrate that the effect of outliers in the radio astronomy context can indeed be modeled by a non-Gaussian heavy-tailed ...
doi:10.1109/tsp.2017.2733496
fatcat:sr2biima6jcl7fr2uyq2axxjni
Relaxed concentrated MLE for robust calibration of radio interferometers
[article]
2017
arXiv
pre-print
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2020; you can also visit the original URL.
The file type is application/pdf.
Other Versions
In this paper, we investigate the calibration of radio interferometers in which Jones matrices are considered to model the interaction between the incident electromagnetic field and the antennas of each ...
In order to design a robust estimator, the noise is assumed to follow a spherically invariant random process (SIRP). ...
CONCLUSION In this paper, we propose a robust calibration algorithm of radio interferometers, where non-structured Jones matrices are used to model the different perturbations introduced along the signal ...
arXiv:1603.01070v3
fatcat:ztumfby2tnfixioxk7ouoh45i4
Bayesian Calibration using Different Prior Distributions: an Iterative Maximum A Posteriori Approach for Radio Interferometers
[article]
2018
arXiv
pre-print
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2020; you can also visit the original URL.
The file type is application/pdf.
In this paper, we aim to design robust estimation techniques based on the compound-Gaussian (CG) process and adapted for calibration of radio interferometers. ...
non-robust Gaussian noise assumption. ...
INTRODUCTION Robust calibration in radio astronomy amounts to estimating all environmental and instrumental perturbation effects which corrupt the signal of interest in a non-Gaussian environment. ...
arXiv:1807.11382v1
fatcat:plv6njunwrcyth5skt4zj4ct3a
Relaxed concentrated MLE for robust calibration of radio interferometers
2016
2016 24th European Signal Processing Conference (EUSIPCO)
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2017; you can also visit the original URL.
The file type is application/pdf.
In this paper, we investigate the calibration of radio interferometers in which Jones matrices are considered to model the interaction between the incident electromagnetic field and the antennas of each ...
In order to design a robust estimator, the noise is assumed to follow a spherically invariant random process (SIRP). ...
CONCLUSION In this paper, we propose a robust calibration algorithm of radio interferometers, where non-structured Jones matrices are used to model the different perturbations introduced along the signal ...
doi:10.1109/eusipco.2016.7760254
dblp:conf/eusipco/OllierKBLP16
fatcat:rtq25nzx75cv7ovj4lte7saryy
Working Principle of the Calibration Algorithm for High Dynamic Range Solar Imaging with Square Kilometre Array Precursor
[article]
2022
arXiv
pre-print
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2022; you can also visit the original URL.
The file type is application/pdf.
Other Versions
(SKA) and other future radio interferometers for producing high-dynamic-range and high-fidelity images of the Sun. ...
With the unique array configuration of the Murchison Widefield Array (MWA), and the robust calibration and imaging pipeline, AIRCARS produces the best spectroscopic snapshot solar images available to date ...
Acknowledgements This scientific work makes use of the Murchison Radio-astronomy Observatory (MRO), operated by the Commonwealth Scientific and Industrial Research Organisation (CSIRO). ...
arXiv:2207.11665v1
fatcat:cjlrsxjcs5dbpmjxcx5qcvyooa
Snowmass2021 Cosmic Frontier White Paper: 21cm Radiation as a Probe of Physics Across Cosmic Ages
[article]
2022
arXiv
pre-print
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2022; you can also visit the original URL.
The file type is application/pdf.
The instrumental challenges, namely building very sensitive and exquisitely calibrated radio telescopes, however, share many commonalities across frequency bands. ...
At redshifts below z<6, the intergalactic medium is largely ionized, but pockets of self-shielded neutral gas form in dense galactic environments and 21cm emission traces the distribution of galaxies. ...
Another is looking for signatures of new physics by searching for non-Gaussianity in 21 cm data [3, 71, 72] . ...
arXiv:2203.07864v1
fatcat:s5xf5ypyhvhirim4qfwzepzz7u
Radio and Optical Interferometry: Basic Observing Techniques and Data Analysis
[chapter]
2013
Planets, Stars and Stellar Systems
Preserved Fulltext
The Internet Archive has a preservation copy of this work in our general collections.
The file type is application/pdf.
Note that this fulltext copy is not of the "primary" version of this work. The version it corresponds to is:
2012 pre-print arXiv:1201.2963v1 fatcat:3vdbbz47mvhetg6wlrgv4r23ky
Interferometers at visible and infrared wavelengths extend angular resolution below the milli-arcsecond level to open up unique research areas in imaging stellar surfaces and circumstellar environments ...
In this chapter the basic principles of interferometry are reviewed with an emphasis on the common features for radio and optical observing. ...
A diversity of packages and data analysis environments are in use for data reduction of interferometer observations. In the radio and mm-wave regime, the most popular packages are AIPS and Miriad. ...
doi:10.1007/978-94-007-5618-2_7
fatcat:epgitqfas5aohebnkh2rv27cdu
RFI excision using a higher order statistics analysis of the power spectrum
2001
Astronomy and Astrophysics
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2017; you can also visit the original URL.
The file type is application/pdf.
This method allows the separation of the Gaussian component due to the natural radio source and the non-Gaussian RFI signal. ...
The application of real time digital signal processing for RFI suppression is found to be effective for radio astronomy telescopes operating in a worsening spectral environment. ...
Type of radio telescope -single dish, connected radio interferometer, VLBI. Single dish radio telescopes are especially vulnerable to RFI. ...
doi:10.1051/0004-6361:20000552
fatcat:cfgxuavxojcubmhyf7yymyd3xu
Tackling the Unique Challenges of Low-frequency Solar Polarimetry with the Square Kilometre Array Low Precursor: Pipeline Implementation
[article]
2022
arXiv
pre-print
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2022; you can also visit the original URL.
The file type is application/pdf.
Other Versions
Polarization of the low-frequency radio emissions has long been recognized as one of the few effective observational probes of magnetic fields in the mid and high corona. ...
Widefield Array (MWA), a Square Kilometre Array (SKA) precursor and our unsupervised and robust polarization calibration and imaging software pipeline dedicated for the Sun -- Polarimetry using Automated ...
It uses a custom-designed parallelization framework, which also does the scheduling for non-HPC environments. ...
arXiv:2209.06666v2
fatcat:djvidy436jdh7nhpwhb6h2r6m4
Solar-stellar atmospheric tomography with mm-radio snapshot spectroscopic imaging
[article]
2023
arXiv
pre-print
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2023; you can also visit the original URL.
The file type is application/pdf.
Sensitive modern mm and radio interferometers let us explore solar/stellar activity covering a range of energy scales at sub-second and sub-MHz resolution over wide operational bandwidths. ...
The impact of these tools and novel data in field of solar/stellar research will be summarised with future prospects. ...
This research made use of NASA's Astrophysics Data System (ADS). AM is grateful to the developers of Python3 ...
arXiv:2311.10294v1
fatcat:d56ktifb35gxdbk6ztljxicmby
NEW MEASUREMENTS OF THE RADIO PHOTOSPHERE OF MIRA BASED ON DATA FROM THE JVLA AND ALMA
2015
Astrophysical Journal
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2020; you can also visit the original URL.
The file type is application/pdf.
Other Versions
The shape of the radio photosphere is found to be slightly elongated, with a flattening of 10-20 brightness non-uniformities on the surface of Mira at radio wavelengths. ...
The stellar disk is resolved, and the measurements indicate a decrease in the size of the radio photosphere at higher frequencies, as expected if the opacity decreases at shorter wavelengths. ...
This effect may therefore arise in part from the intrinsically non-Gaussian shape of the real interferometer beam and/or deconvolution biases. ...
doi:10.1088/0004-637x/808/1/36
fatcat:cwz7us762bebfg7fbf6wnvvpsi
Radio jets in NGC 1068 with e-MERLIN and VLA: structure and morphology
[article]
2023
arXiv
pre-print
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2024; you can also visit the original URL.
The file type is application/pdf.
Components NE, C and S2 have steep spectra indicative of optically-thin non-thermal emission domination between 5 and 21 GHz. Component S1, which is where the AGN resides, has a flat radio spectrum. ...
We compare these new data with the MERLIN and VLA data observed in 1983, 1992 and 1995 and report a flux decrease by a factor of 2 in component C, suggesting variability of this jet component. ...
We thank the Technical University of Kenya (TUK) and Development in Africa with Radio Astronomy (DARA) for funding this research. ...
arXiv:2312.09722v1
fatcat:wklomwv46nckdnfp2vnwsb5smm
Cosmology with a SKA HI intensity mapping survey
[article]
2015
arXiv
pre-print
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2019; you can also visit the original URL.
The file type is application/pdf.
They can also be used to probe physics on extremely large scales, where precise measurements of spatial curvature and primordial non-Gaussianity can be used to test inflation; on small scales, by measuring ...
the sum of neutrino masses; and at high redshifts where non-standard evolution models can be probed. ...
This correction grows on large scales as ∆b ∝ f NL k −2 for primordial non-Gaussianity of the local type, where f NL is the non-Gaussian parameter. ...
arXiv:1501.03989v1
fatcat:2ajlhdschna3tdixpef4rpfoeq
Resolving the collimation zone of an intermediate-mass protostar
[article]
2022
arXiv
pre-print
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2022; you can also visit the original URL.
The file type is application/pdf.
We report new VLA and e-MERLIN high resolution and sensitivity images of the Triple Radio continuum Source in the Serpens star forming region. ...
In light of these results, we propose the scenario in which both a highly-collimated jet and a wide-angle wind coexist to be the most plausible to explain our observations, either launched by the X-wind ...
with the the VLA and e-MERLIN radio interferometers. ...
arXiv:2205.10422v1
fatcat:txganbjcyzesjl2ochhykwkpq4
MeerKLASS: MeerKAT Large Area Synoptic Survey
[article]
2017
arXiv
pre-print
Preserved Fulltext
A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2019; you can also visit the original URL.
The file type is application/pdf.
The combination with multi-wavelength data will give unique additional information, such as exquisite constraints on primordial non-Gaussianity using the multi-tracer technique, as well as a better handle ...
It will also produce a large continuum galaxy sample down to a depth of about 5 μJy in L-band, which is quite unique over such large areas and will allow studies of the large-scale structure of the Universe ...
Multi-tracer constraints on primordial non-Gaussianity In recent years we have seen an increased interest in testing the Gaussianity of primordial perturbations, motivated by the plethora of inflationary ...
arXiv:1709.06099v1
fatcat:mcqsmthxdnhvlegdrdyqpam4ni
« Previous
Showing results 1 — 15 out of 2,795 results