18 research outputs found
A multi-wavelength pipeline for pulsar searches
Pulsar studies in the recent years have shown, more than others, to have
benefited from a multi-wavelength approach. The INAF - Astronomical Observatory
in Cagliari (INAF-OAC) is a growing facility with a young group devoted to
pulsar and fast transients studies across the electromagnetic spectrum. Taking
advantage of this expertise we have worked to provide a suite of
multi-wavelength software and databases for the observations of pulsars and
compact Galactic objects at the Sardinia Radio Telescope (SRT). In turn, radio
pulsar observations at SRT will be made available, in a processed format, to
gamma-ray searches using AGILE and Fermi gamma-ray satellite and, in a near
future, they will be complementary to polarimetric X-ray observations with
IXPE.Comment: Accepted for publications in Rendiconti Lincei as Proceedings of "A
Decade of AGILE: Results, Challenges and Prospects of Gamma-Ray Astrophysics
Il nuovo Planetario INAF-OAC ...e quindi entrammo a riveder le stelle
Si tratta del poster di un congresso, non pubblicato in atti di convegnoIl poster è relativo al nuovo Planetario dell'INAF-Osservatorio Astronomico di Cagliari e ne illustra le caratteristiche tecniche, le attività che già vi si stanno svolgendo e quelle in preparazione
A multi-wavelength pipeline for pulsar observations
The Astronomical Observatory in Cagliari (OAC) is a growing facility with a group devoted to pulsar studies across the electromagnetic spectrum. Taking advantage of this expertise we have worked to provide a suite of multi-wavelength software and databases for the observations of pulsars and compact Galactic objects at the Sardinia Radio Telescope (SRT, Bolli et al. 2015, Prandoni et al. 2017)
A dedicated pipeline to analyse solar data with INAF radio telescopes: SUNPIT (SUNdish PIpeline Tool)
This technical note describes SUNPIT (SUNdish PIpeline Tool) - the pipeline aimed at the imaging procedure and the data analysis of the radio solar data - and guides the user to properly reduce and analyse the solar data.
SUNPIT is designed for radio data acquired with some radio telescopes of the INAF Network: the Sardinia Radio Telescope (SRT), and the Medicina Radio Telescope.
The present user manual follows the development of software for solar imaging and data analysis of Active Regions (ARs), performed in the framework of the INAF Proposal "SunDish Project" (PI: A. Pellizzoni).
This project has been active since 2018 with the goal of monitoring the solar atmosphere at high radio frequencies (at present 18 - 26 GHz) through single-dish observations.
These solar observations will be enhanced through the upgrading of SRT with the new cryogenically cooled receivers, including a 19-feed in Q-band (33 - 50 GHz) and a 16-feed in W-band (75 - 116 GHz), in the context of the National Operative Programme (Programma Operativo Nazionale-PON); this project will provide in the near future an upgrading with the new receivers up to 116 GHz also for the Medicina and Noto Radio Telescopes, to provide the scientific community with the instrumentation suited to the study of the Universe at high radio frequencies.
SUNPIT will be suitable for the data of these new forthcoming receivers, when available for the scientific community.
SUNPIT produces a complete analysis of a solar map in about one hour, saving a directory which contains images, plots and several tables with the physical information of the solar disk and ARs (brightness temperatures, fluxes and spectral indices, with the respective errors).
This pipeline – successfully tested – represents a crucial tool (1) to analyse solar images observed with the radio telescopes of the INAF Network, and (2) for the Space Weather monitoring network and forecast (soon available) along the solar cycle
C-band observations of supernova remnants with SRT: 2 - Calibrations
Following to the Astronomical Validation report n°6 (AV-rep-006; Egron et al.
2015) dedicated to the C-band imaging performances of SRT through the observation of
two Supernova Remnants (3C157 and W44), this second note is devoted to the calibration
of the resulting maps
C-band observations of supernova remnants with SRT: 1 - Imaging performances
We report on observations of Supernova Remnants (SNR) with SRT in the frame of
Astronomical Validation (AV) test activities. These tests are aimed to assess single-dish
imaging performances of “SRT first light receivers” coupled with Total Power (TP)
backend and related hw/sw subsystems/procedures (including innovative ad hoc imaging
techniques based on OTF scans)
Single-dish total power imaging of bright sources: mapping of 3c295 in C-band and K-band
In the frame of AV tests “Single-‐Dish Total Power Imaging of Bright Sources (I:s/w test)” (AV SNR1 test) we
performed C band and K band (only central feed) imaging of point-‐like bright calibration sources (i.e. 3C295 in
particular)
Tracking the X-Ray Polarization of the Black Hole Transient Swift J1727.8–1613 during a State Transition
We report on an observational campaign on the bright black hole (BH) X-ray binary Swift J1727.8–1613 centered around five observations by the Imaging X-ray Polarimetry Explorer. These observations track for the first time the evolution of the X-ray polarization of a BH X-ray binary across a hard to soft state transition. The 2–8 keV polarization degree decreased from ∼4% to ∼3% across the five observations, but the polarization angle remained oriented in the north–south direction throughout. Based on observations with the Australia Telescope Compact Array, we find that the intrinsic 7.25 GHz radio polarization aligns with the X-ray polarization. Assuming the radio polarization aligns with the jet direction (which can be tested in the future with higher-spatial-resolution images of the jet), our results imply that the X-ray corona is extended in the disk plane, rather than along the jet axis, for the entire hard intermediate state. This in turn implies that the long (≳10 ms) soft lags that we measure with the Neutron star Interior Composition ExploreR are dominated by processes other than pure light-crossing delays. Moreover, we find that the evolution of the soft lag amplitude with spectral state does not follow the trend seen for other sources, implying that Swift J1727.8–1613 is a member of a hitherto undersampled subpopulation
VLBI experiments with the dissemination of a common clock via coherent optical fiber link
Atomic clock synchronization plays an important role in both astronomical and geodetic Very Long Baseline Interferometry, as time and frequency standards are provided by station clocks. National metrological institutes have recently started streaming (via optical fiber links) frequency references from ultra-stable clocks based on optical line transitions in Strontium/Ytterbium laser-cooled lattices. Optical lattice clocks are already two orders of magnitude more stable than the radio station H-masers. In this talk we will describe how the Italian Qauntum Backbone (IQB) was used to carry out a series of European geodetic VLBI experiments in which the Medicina and Matera radio stations were connected to the same remote clock located at the Italian Metrological institute in Turin, via the IQB optical link. In the foreseeable future a European VLBI network of radio stations could be connected via optical fiber links to a single very high-performance clock hosted by a European Metrological institute
SRT performance measurements (2018-2021)
Tests of characterization are periodically performed at SRT in order to check the status of the antenna, ensure a good functioning of the different components (e.g. active surface, receivers, backends, etc), and improve the observing performances at the different frequencies. In particular, the tests include measurements of beam shape, pointing, gain curves and focus for the different receivers (L, C, X and K-bands).
We report the results of the main tests carried out after a long stop of the antenna due to the reparation of the main servo motors chillers in 2020 and compare them with those carried out during the recommissioning in 2018 (after the change of the actuators of the active surface).
These results will be useful in order to compare the new status of the antenna after the upgrade of the new receivers at higher frequency (PON)