A. Basyrov
A5023407841- Solar and Space Plasma Dynamics
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Superconducting and THz Device Technology
- Adaptive optics and wavefront sensing
- Blind Source Separation Techniques
- Dark Matter and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Calibration and Measurement Techniques
- Astro and Planetary Science
- Geophysics and Gravity Measurements
- Optical Polarization and Ellipsometry
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Image and Signal Denoising Methods
- Neural Networks and Applications
- GNSS positioning and interference
- Optical measurement and interference techniques
- Gamma-ray bursts and supernovae
- Precipitation Measurement and Analysis
- Wireless Communication Networks Research
- Advanced Wireless Communication Techniques
University of Oslo
2022-2024
Stockholm University
2024
University of Milan
2023
We present the first Bayesian method for tomographic decomposition of plane-of-sky orientation magnetic field with use stellar polarimetry and distance. This standalone inversion presents an important step forward in reconstructing magnetized interstellar medium (ISM) three dimensions within dusty regions. develop a model which polarization signal from ISM is described by thin layers at various distances, working assumption should be satisfied small-angular circular apertures. Our modeling...
We describe the BeyondPlanck project in terms of motivation, methodology and main products, provide a guide to set companion papers that each result fuller detail. implement complete end-to-end Bayesian analysis framework for Planck LFI observations. The primary product is full joint posterior distribution $P(\omega|d)$, where $\omega$ represents all free instrumental, astrophysical, cosmological parameters. Notable advantages this approach are seamless propagation uncertainties; accurate...
Abstract We present a study of the impact beam far side-lobe lack knowledge on measurement Cosmic Microwave Background B -mode signal at large scale. Beam side-lobes induce mismatch in transfer function Galactic foregrounds between dipole and higher multipoles which degrads performances component separation methods. This leads to foreground residuals CMB map. It is expected be one main source systematic effects future polarization observations. Thus, it becomes crucial for all-sky survey...
We present posterior sample-based cosmic microwave background (CMB) constraints from Planck LFI and WMAP observations derived through global end-to-end Bayesian processing. use these samples to study correlations between CMB, foreground, instrumental parameters, we identify a particularly strong degeneracy CMB temperature fluctuations free-free emission on intermediate angular scales, which is mitigated model reduction, masking, resampling. compare our posterior-based results with previous...
Cosmic birefringence is a parity-violating effect that might have rotated the plane of linearly polarized light cosmic microwave background (CMB) by an angle $β$ since its emission. This has recently been measured to be non-zero at statistical significance $3.6σ$ in official Planck PR4 and 9-year WMAP data. In this work, we constrain using reprocessed BeyondPlanck LFI Cosmoglobe DR1 polarization maps. These novel maps both lower systematic residuals more complete error description than...
We present the first degree-scale tomography map of dusty magnetized interstellar medium (ISM) from stellar polarimetry and distance measurements. used RoboPol polarimeter at Skinakas Observatory to conduct a survey starlight polarization in region sky 4 square degrees. propose Bayesian method decompose stellar-polarization source field along invert 3D volume occupied by observed stars. it obtain ISM. Specifically, we produced orientation plane-of-sky (POS) component magnetic threading...
Abstract The detection of primordial B modes the cosmic microwave background (CMB) could provide information about early stages Universe's evolution. faintness this signal requires exquisite calibration accuracy and control instrumental systematic effects which otherwise bias measurements. In work, we study impact an imperfect relative polarisation gain on recovered value tensor-to-scalar ratio r for LiteBIRD experiment, through application blind Needlet Internal Linear Combination (NILC)...
We present the first model of full-sky polarized synchrotron emission that is derived from all WMAP and Planck LFI frequency maps. The basis this analysis set end-to-end reprocessed C OSMOGLOBE Data Release 1 (DR1) sky maps presented in a companion paper, which have significantly lower instrumental systematics than legacy products each experiment. find resulting amplitude map has an average noise rms per 2° full width at half maximum (FWHM) beam 3.2 μK 30 GHz. This 30% recently released B...
We present Planck LFI frequency sky maps derived within the BeyondPlanck framework. This framework draws samples from a global posterior distribution that includes instrumental, astrophysical and cosmological parameters, main product is an entire ensemble of map samples. allows for computationally convenient end-to-end propagation low-level instrumental uncertainties into higher-level science products. show two dominant sources systematic are correlated noise gain fluctuations, products...
LiteBIRD, the next-generation cosmic microwave background (CMB) experiment, aims for a launch in Japan's fiscal year 2032, marking major advancement exploration of primordial cosmology and fundamental physics. Orbiting Sun-Earth Lagrangian point L2, this JAXA-led strategic L-class mission will conduct comprehensive mapping CMB polarization across entire sky. During its 3-year mission, LiteBIRD employ three telescopes within 15 unique frequency bands (ranging from 34 through 448 GHz),...
We revisit the impact of finite time responses bolometric detectors used for deep observations cosmic microwave background (CMB). Until now, bolometer transfer functions have been accounted through a two-step procedure by first deconvolving an estimate their Fourier-space representation from raw time-ordered data (TOD), and then averaging deconvolved TOD into pixelized maps. However, many experiments, including Planck High Frequency Instrument (HFI), it is necessary to apply additional...
Context. Next-generation wide-field optical polarimeters such as Wide-Area Linear Optical Polarimeters (WALOPs) have a field of view (FoV) tens arcminutes. Wide-field polarimetric flat sources are essential to the efficient and accurate calibration these instruments. However, no established standard or exist at present. Aims. This study tests feasibility using polarized sky patches size around 10 × arcminutes 2 , distance up 20° from Moon, on bright-Moon nights linear source. Methods. We...
The Wide-Area Linear Optical Polarimeter (WALOP)-South instrument is an upcoming wide-field and high-accuracy optical polarimeter to be used as a survey for carrying out the Polar-Areas Stellar Imaging in Polarization High Accuracy Experiment (PASIPHAE) program. Designed operate one-shot four-channel four-camera imaging polarimeter, it will have field of view $35\times 35$ arcminutes measure Stokes parameters $I$, $q$, $u$ single exposure SDSS-r broadband filter. design goal achieve overall...
We present a Gibbs sampling solution to the map-making problem for CMB measurements, building on existing destriping methodology. breaks computationally heavy into two separate steps; noise filtering and map binning. Considered as steps, both are much cheaper than solving combined problem. This provides huge performance benefit compared traditional methods, allows us first time bring baseline length single sample. apply procedure simulated Planck 30 GHz data. find that gaps in time-ordered...
Two unique wide-field and high-accuracy polarimeters named WALOP (Wide-Area Linear Optical Polarimeter)- North WALOP-South are currently under development at the Inter-University Center for Astronomy Astrophysics (IUCAA), India, to create a large area optical polarization map of sky upcoming PASIPHAE survey. These instruments designed achieve linear polarimetric measurement accuracy 0.1% across field view (FoV) 30×30 arcminutes. The instrument will be installed first on 1 m telescope...
We revisit the impact of finite time responses bolometric detectors used for deep observations cosmic microwave background (CMB). Until now, bolometer transfer functions have been accounted through a two-step procedure by first deconvolving an estimate their Fourier-space representation from raw time-ordered data (TOD), and then averaging deconvolved TOD into pixelized maps. However, many experiments, including Planck High Frequency Instrument (HFI), it is necessary to apply additional...
We derive new constraints on the CIB monopole spectrum from reprocessed COBE-DIRBE sky maps with lower instrumental and astrophysical contamination than legacy DIRBE maps. These have been generated through a global Bayesian analysis framework that simultaneously fits cosmological, astrophysical, parameters, described in series of papers referred to as Cosmoglobe DR2. applied this method Calibrated Individual Observations, complemented by selected HFI FIRAS break key degeneracies, well WISE...
Future cosmic microwave background (CMB) experiments are primarily targeting a detection of the primordial $B$-mode polarisation. The faintness this signal requires exquisite control systematic effects which may bias measurements. In work, we derive requirements on relative calibration accuracy overall polarisation gain ($\Delta g_\nu$) for LiteBIRD experiment, through application blind Needlet Internal Linear Combination (NILC) foreground-cleaning method. We find that minimum variance...
The Wide-Area Linear Optical Polarimeters (WALOPs) are two instruments - WALOPNorth and WALOPSouth that will be installed at the Skinakas South African Astronomical Observatories respectively. Their goal is to work towards a polarimetric map of Galaxy, for needs PASIPHAE collaboration. WALOP instruments, able operate smoothly, require custom-made software fit their (and survey's) specifications. We present said software's specifications methods technologies used meet these requirements.
We present the first global Bayesian analysis of time-ordered DIRBE data within Cosmoglobe framework, building on same methodology that has previously been successfully applied to Planck LFI and WMAP. These are analyzed jointly with COBE-FIRAS, Gaia, HFI, WISE, allowing for more accurate instrumental astrophysical characterization than possible through single-experiment analysis. This paper provides an overview pipeline main results, we characterize a new set zodiacal light subtracted...
The Wide Area Linear Optical Polarimeter North (WALOP-North) is an optical polarimeter designed for the needs of PASIPHAE survey. It will be installed on 1.3m telescope at Skinakas Observatory in Crete, Greece. After commissioning, it measure polarization millions stars high Galactic latitude, aiming to hundreds per $deg^2$. astronomical filter used instrument a modified, polarimetrically-neutral broadband SDSS-r. This pioneering one due its large field-of-view (FoV) $30\times 30$ $arcmin^2$...
We implement support for a cosmological parameter estimation algorithm in Commander and quantify its computational efficiency cost. For semi-realistic simulation similar to Planck LFI 70 GHz, we find that the cost of producing one single sample is about 20 CPU-hours typical Markov chain correlation length ∼100 samples. The net effective per independent ∼2000 CPU-hours, comparison with all low-level processing costs 812 WMAP C OSMOGLOBE Data Release 1. Thus, although technically possible run...
End-to-end simulations play a key role in the analysis of any high-sensitivity CMB experiment, providing high-fidelity systematic error propagation capabilities unmatched by other means. In this paper, we address an important issue regarding such simulations, namely how to define inputs terms sky model and instrument parameters. These may either be taken as constrained realization derived from data, or random independent data. We refer these Bayesian frequentist respectively. show that two...
We present Planck LFI frequency sky maps derived within the BeyondPlanck framework. This framework draws samples from a global posterior distribution that includes instrumental, astrophysical and cosmological parameters, main product is an entire ensemble of map samples. allows for computationally convenient end-to-end propagation low-level instrumental uncertainties into higher-level science products. show two dominant sources systematic are correlated noise gain fluctuations, products...
We present cosmological parameter constraints as estimated using the Bayesian BeyondPlanck (BP) analysis framework. This method supports seamless end-to-end error propagation from raw time-ordered data to final parameters. As a first demonstration of method, we analyze Planck LFI observations, combined with selected external (WMAP 33-61GHz, HFI DR4 353 and 857GHz, Haslam 408MHz) in form pixelized maps which are used break critical astrophysical degeneracies. Overall, all results generally...