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X-ORIGINAL-URL:https://www.oact.inaf.it
X-WR-CALDESC:Eventi per Osservatorio Astrofisico di Catania
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DTSTART:20220101T000000
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BEGIN:VEVENT
DTSTART;TZID=UTC:20260520T113000
DTEND;TZID=UTC:20260520T123000
DTSTAMP:20260514T080850Z
CREATED:20260514T080847Z
LAST-MODIFIED:20260514T080850Z
UID:19680-1779276600-1779280200@www.oact.inaf.it
SUMMARY:The Nature of Polarized Sources in the MIGHTEE XMM-LSS Deep Field
DESCRIPTION:Recording: NOT AVAILABLE \nDATE: Wednesday\, May 20\, 11:30 a.m. \nORGANIZER: INAF-OACT \nLOCATION: AULA OVEST (INAF-OACT) + remote \nLink for the remote audience:https://meet.google.com/wvf-uwxo-oyj \nSPEAKER: Lennart Heino (INAF) \nABSTRACT:This study explores the polarized emission of the faint extragalactic radio sources in the MIGHTEE (MeerKAT International Giga-Hertz Tiered Extragalactic Exploration\, Jarvis et al.\, 2016) survey in order to systematically study cosmic magnetic fields in galaxies to high redshift. Reaching a sensitivity of 1.5 µJy/beam at a resolution of 5 arcseconds\, MIGHTEE is providing an opportunity to chart the evolution of polarized emission from distant galaxies over cosmic time. \nThe MIGHTEE survey detects polarized emission for a large number of radio sources down to total intensity flux densities of the order of 100 µJy. At these flux densities the source population is increasingly dominated by star-forming galaxies (SFGs) as opposed to active galactic nuclei (AGNs). While polarized emission of AGN can be traced to very distant galaxies\, polarized emission of SFGs at moderate distance has been detected only once. \nI use multi-wavelength criteria to classify MIGHTEE radio objects as either SFG or AGN. I perform Rotation Measure Synthesis (RMSY) on the spectro-polarimetric data cubes and use the polarization and RMSY spectra to search for polarized emission. A comparative analysis of the polarization properties of SFGs and AGNs is performed. The analysis is extended to the lowest possible flux densities using stacking techniques. I will show preliminary results of the MeerKAT polarization studies of radio sources down to a sensitivity at the micro-Jansky level. \n  \nA few rules:— before joining\, make sure you are using your institutional inaf.it account if you have one (otherwise we will grant you permission to join)— please do not forget to mute your microphone and switch off your webcam when access the virtual room— for questions leave a message in the chat\, the answers at the end of the webinar \n 
URL:https://www.oact.inaf.it/event/the-nature-of-polarized-sources-in-the-mightee-xmm-lss-deep-field/
LOCATION:Sede A. Riccò\, Via Santa Sofia 78\, Catania
CATEGORIES:Eventi & Seminari
ATTACH;FMTTYPE=image/png:https://www.oact.inaf.it/wp-content/uploads/2026/05/cover-slide.png
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BEGIN:VEVENT
DTSTART;TZID=UTC:20250430T110000
DTEND;TZID=UTC:20250430T120000
DTSTAMP:20250428T210924Z
CREATED:20250428T210420Z
LAST-MODIFIED:20250428T210924Z
UID:18011-1746010800-1746014400@www.oact.inaf.it
SUMMARY:Precision Meter-wavelength Polarimetry with the Very Large Array
DESCRIPTION:Recording: https://www.oact.inaf.it/seminars/ \nDATE: Wednesday\, April 30\, 11:00 a.m. \nORGANIZER: INAF-OACT \nLOCATION: AULA OVEST (INAF-OACT) + remote \nLink for the remote audience:https://meet.google.com/wvf-uwxo-oyj \nSPEAKER: Rick Perley (National Radio Astronomy Observatory – USA) \nABSTRACT:Accurate imaging polarimetry at meter wavelengths requires removal of the highly variable ionospheric Faraday rotation (IFRM) with an accuracy of 0.1 rad/m^2 or better. Models to estimate the VTEC using GNSS timing data\, combined with global terrestrial magnetic field models have been developed over the past 25 years.  Estimating the accuracy of these models requires observations of a source of known intrinsic electric vector position angle (EVPA) over a wide rage of ionospheric conditions.Using eight VLA polarimetric observations of the moon spanning ten years using the VLA’s P-band (295 — 445 MHz) receivers\, we have tested the accuracy of seven global IONEX models produced by the AIPS program TECOR\, and the regional model derived by ALBUS.All seven global models overestimate the IFRM\, typically by 0.5 to 1.0 rad/m^2 — a value which remains constant over many hours\, including day — night transitions.  The ‘ALBUS’ model\, which uses GNSS ground station data within ~300 km of the requested site\, generates predictions which are always the closest — usually with 0.2 rad/m^2— to the observed values. \n  \nA few rules:— before joining\, make sure you are using your institutional inaf.it account if you have one (otherwise we will grant you permission to join)— please do not forget to mute your microphone and switch off your webcam when access the virtual room— for questions leave a message in the chat\, the answers at the end of the webinar— the seminar will be recorded\, so if you are interested in it\, please contact us to get the link to the registration.
URL:https://www.oact.inaf.it/event/precision-meter-wavelength-polarimetry-with-the-very-large-array/
LOCATION:Sede A. Riccò\, Via Santa Sofia 78\, Catania
CATEGORIES:Eventi & Seminari
ATTACH;FMTTYPE=image/jpeg:https://www.oact.inaf.it/wp-content/uploads/2025/04/Locandine-eventi-OACT-2.jpg
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BEGIN:VEVENT
DTSTART;TZID=UTC:20250407T110000
DTEND;TZID=UTC:20250407T120000
DTSTAMP:20250405T091543Z
CREATED:20250405T091539Z
LAST-MODIFIED:20250405T091543Z
UID:17926-1744023600-1744027200@www.oact.inaf.it
SUMMARY:Non-standard signatures from CMB polarisation with an insight into the new technological challenges
DESCRIPTION:Recording: https://www.oact.inaf.it/seminars/ \nDATE:  Monday\, April 7\, 11:00 a.m. \nORGANIZER: INAF-OACT \nLOCATION: AULA OVEST (INAF-OACT) + remote \nLink for the remote audience:https://meet.google.com/wvf-uwxo-oyj \nSPEAKER: Dr. Matteo Billi (University of Catania) \nABSTRACT:In this seminar\, I will focus on non-standard signatures from CMB polarisation that may indicate the existence of new phenomena beyond the standard models of cosmology and particle physics\, from both theoretical and observational perspectives. ESA’s Planck mission has observed CMB temperature anisotropies at the cosmic variance limit\, but polarisation remains to be further investigated. CMB polarisation data are important not only because they contribute to provide tighter constraints on cosmological parameters but also because they allow the study of physical processes that would be excluded if only the CMB temperature maps were considered. I use polarisation data into account to assess the statistical significance of the anomalies currently observed only in the CMB temperature map\, and to constrain the Cosmic Birefringence (CB) effect\, which is expected in parity-violating extensions of the standard electromagnetism.Measuring CMB polarisation is technically challenging because the polarised signal is much fainter than the temperature signal\, and accurate polarisation estimates require exquisite control of systematic effects. To investigate the impact of spurious signals in upcoming CMB polarisation experiments\, I present a study of the interplay between half-wave plate (HWP) non-idealities and the beams of the instrument for the next generation of CMB experiments\, with an insight into how this instrumental contamination affects the measurement of the cosmic birefringence effect. \n  \nA few rules:— before joining\, make sure you are using your institutional inaf.it account if you have one (otherwise we will grant you permission to join)— please do not forget to mute your microphone and switch off your webcam when access the virtual room— for questions leave a message in the chat\, the answers at the end of the webinar— the seminar will be recorded\, so if you are interested in it\, please contact us to get the link to the registration.
URL:https://www.oact.inaf.it/event/non-standard-signatures-from-cmb-polarisation-with-an-insight-into-the-new-technological-challenges/
LOCATION:Sede A. Riccò\, Via Santa Sofia 78\, Catania
CATEGORIES:Eventi & Seminari
ATTACH;FMTTYPE=image/jpeg:https://www.oact.inaf.it/wp-content/uploads/2025/04/seminario_Billi.jpg
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BEGIN:VEVENT
DTSTART;TZID=UTC:20231120T113000
DTEND;TZID=UTC:20231120T123000
DTSTAMP:20231114T091442Z
CREATED:20231114T091439Z
LAST-MODIFIED:20231114T091442Z
UID:14891-1700479800-1700483400@www.oact.inaf.it
SUMMARY:Challenges for the forthcoming CMB polarization experiments
DESCRIPTION:Recording: https://www.oact.inaf.it/seminars/ \nDATE: Monday\, November 20\, 11:00 a.m. \nORGANIZER: INAF OACT \nLOCATION: AULA OVEST (INAF-OACT) + remote \nLink for the remote audience:https://meet.google.com/wvf-uwxo-oyj \nSPEAKER: Prof. Giuseppe Puglisi (DFA – Università di Catania) \nABSTRACT:One of the major challenges in the context of the Cosmic Microwave Background (CMB) radiation is to detect a polarization pattern\, the so called B-modes of CMB polarization\, that are thought to be directly linked to the space-time fluctuations present in the Universe at the very first instants of life. To date\, several challenges have prevented to detect the B-modes partly because of the lower sensitivity of the detectors. Our own Galaxy is observed in this context as a foreground contamination. However the awareness of improving the modeling of its polarized emission has been constantly increase not only to assess the cosmological signals but also to provide new insights onto the Galactic magnetic field probed with the Galactic polarized emissions\, e.g. synchrotron and thermal dust. This is particularly relevant in order to better characterize the foreground contamination for future CMB experiments (e.g. SO\, LiteBIRD\, CMB-S4 )\, where unprecedented polarization sensitivities are expected to be achieved in the coming decades. \n  \nA few rules:— in case of large in-person attendance\, attendees may be asked to wear a face mask— before joining\, make sure you are using your institutional inaf.it account if you have one (otherwise we will grant you permission to join)— please do not forget to mute your microphone and switch off your webcam when access the virtual room— for questions leave a message in the chat\, the answers at the end of the webinar— the seminar will be recorded\, so if you are interested in it\, please contact us to get the link to the registration.
URL:https://www.oact.inaf.it/event/challenges-for-the-forthcoming-cmb-polarization-experiments/
LOCATION:Sede A. Riccò\, Via Santa Sofia 78\, Catania
CATEGORIES:Eventi & Seminari
ATTACH;FMTTYPE=image/jpeg:https://www.oact.inaf.it/wp-content/uploads/2023/11/seminario_puglisi.jpg
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