An atmosphere monitoring system for the Sardinia radio telescope

Buffa, Franco; Bolli, Pietro; Sanna, Giovanna Maria; Serra, G.

doi:10.1088/1361-6501/28/1/014004

Cited by 12 publications

(10 citation statements)

References 11 publications

(26 reference statements)

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“…We then modelled the T sys trend with the airmass model to obtain the zenithal opacity, τ . The values of τ derived from the sky dip were generally in good agreement with those provided by the radiometer working at the SRT site (Buffa et al 2017). We also used the calibrator 3C 286 as a reference for the absolute polarization position angle (we assumed the values from Perley & Butler 2013).…”

Section: Srt Observationssupporting

confidence: 64%

Spectropolarimetric observations of the CIZA J2242.8+5301 northern radio relic: no evidence of high-frequency steepening

Loi

Murgia

Vacca

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Observations of radio relics at very high frequency (>10 GHz) can help to understand how particles age and are (re-)accelerated in galaxy cluster outskirts and how magnetic fields are amplified in these environments. In this work, we present new single-dish 18.6 GHz Sardinia Radio Telescope and 14.25 GHz Effelsberg observations of the well known northern radio relic of CIZA J2242.8+5301. We detected the relic which shows a length of ∼1.8 Mpc and a flux density equal to $\rm S_{14.25\, GHz}=(9.5\pm 3.9)\, mJy$ and $\rm S_{18.6\, GHz}=(7.67\pm 0.90)\, mJy$ at 14.25 GHz and 18.6 GHz respectively. The resulting best-fit model of the relic spectrum from 145 MHz to 18.6 GHz is a power-law spectrum with spectral index α = 1.12 ± 0.03: no evidence of steepening has been found in the new data presented in this work. For the first time, polarisation properties have been derived at 18.6 GHz, revealing an averaged polarisation fraction of $\sim 40\%$ and a magnetic field aligned with the ’filaments’ or ’sheets’ of the relic.

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Section: Srt Observationssupporting

confidence: 64%

Spectropolarimetric observations of the CIZA J2242.8+5301 northern radio relic: no evidence of high-frequency steepening

Loi

Murgia

Vacca

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…The K-band observations performed with SRT are strongly dependent on the atmospheric conditions, i.e. the opacity and water vapor content (Nasir et al 2011, Buffa et al 2017. Indeed, the observation of Tycho carried out on 24 February 2016 (MJD 57442) in optimal opacity conditions and in the absence of a cloud cover led to a high signal-to-noise ratio map that allowed us to perform an efficient baseline subtraction, which leads to a low RMS value (see Table1).…”

Section: Resultsmentioning

confidence: 99%

“…The gain curve was obtained through the calculation of a conversion factor, defined as the ratio between the observed counts from the calibrators and their expected flux density (counts/Jy). Our gain curves implicitly include the attenuation effect due to the atmospheric opacity (in the range 0.04−0.12 Np during the observations; Buffa et al 2016, Buffa et al 2017, which also affected the target observations. While the calibration measurements were taken temporally close to the target observations, the opacity conditions could in principle have been slightly different when we observed the calibrators and targets.…”

Section: Data Calibration and Map Productionmentioning

confidence: 99%

Investigating the high-frequency spectral features of SNRs Tycho, W44, and IC443 with the Sardinia Radio Telescope

Loru

Egron

Righini

et al. 2018

Monthly Notices of the Royal Astronomical Society

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The main characteristics in the radio continuum spectra of Supernova Remnants (SNRs) result from simple synchrotron emission. In addition, electron acceleration mechanisms can shape the spectra in specific ways, especially at high radio frequencies. These features are connected to the age and the peculiar conditions of the local interstellar medium interacting with the SNR. Whereas the bulk radio emission is expected at up to 20 − 50 GHz, sensitive high-resolution images of SNRs above 10 GHz are lacking and are not easily achievable, especially in the confused regions of the Galactic Plane. In the framework of the early science observations with the Sardinia Radio Telescope in February-March 2016, we obtained high-resolution images of SNRs Tycho, W44 and IC443 that provided accurate integrated flux density measurements at 21.4 GHz: 8.8 ± 0.9 Jy for Tycho, 25 ± 3 Jy for W44 and 66 ± 7 Jy for IC443. We coupled the SRT measurements with radio data available in the literature in order to characterise the integrated and spatially-resolved spectra of these SNRs, and to find significant frequency-and region-dependent spectral slope variations. For the first time, we provide direct evidence of a spectral break in the radio spectral energy distribution of W44 at an exponential cutoff frequency of 15 ± 2 GHz. This result constrains the maximum energy of the accelerated electrons in the range 6 − 13 GeV, in agreement with predictions indirectly derived from AGILE and Fermi-LAT gammaray observations. With regard to IC443, our results confirm the noticeable presence of a bump in the integrated spectrum around 20 − 70 GHz that could result from a spinning dust emission mechanism.

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“…For a detailed description of the tool and of its usage, we refer to Vacca et al (2013). Meteo Forecasting: this tool uses a numerical weather prediction model on timescales of 36 h to allow for dynamic scheduling (for more details, see Nasir et al 2013;Buffa et al 2016). ScheduleCreator: this tool produces properly formatted schedules for Nuraghe, the telescope control software, for all available observing modes (sidereal tracking, on-off, OTF crossscans, raster scans, and mapping in the equatorial, galactic, and horizontal coordinate frames).…”

Section: Preparing the Observationsmentioning

confidence: 99%

The Sardinia Radio Telescope

Prandoni

Murgia

Tarchi

et al. 2017

A&A

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Context. The Sardinia Radio Telescope (SRT) is the new 64 m dish operated by the Italian National Institute for Astrophysics (INAF).Its active surface, comprised of 1008 separate aluminium panels supported by electromechanical actuators, will allow us to observe at frequencies of up to 116 GHz. At the moment, three receivers, one per focal position, have been installed and tested: a 7-beam K-band receiver, a mono-feed C-band receiver, and a coaxial dual-feed L/P band receiver. The SRT was officially opened in September 2013, upon completion of its technical commissioning phase. In this paper, we provide an overview of the main science drivers for the SRT, describe the main outcomes from the scientific commissioning of the telescope, and discuss a set of observations demonstrating the scientific capabilities of the SRT. Aims. The scientific commissioning phase, carried out in the 2012-2015 period, proceeded in stages following the implementation and/or fine-tuning of advanced subsystems such as the active surface, the derotator, new releases of the acquisition software, etc. One of the main objectives of scientific commissioning was the identification of deficiencies in the instrumentation and/or in the telescope subsystems for further optimization. As a result, the overall telescope performance has been significantly improved. Methods. As part of the scientific commissioning activities, different observing modes were tested and validated, and the first astronomical observations were carried out to demonstrate the science capabilities of the SRT. In addition, we developed astronomeroriented software tools to support future observers on site. In the following, we refer to the overall scientific commissioning and software development activities as astronomical validation. Results. The astronomical validation activities were prioritized based on technical readiness and scientific impact. The highest priority was to make the SRT available for joint observations as part of European networks. As a result, the SRT started to participate (in shared-risk mode) in European VLBI Network (EVN) and Large European Array for Pulsars (LEAP) observing sessions in early 2014. The validation of single-dish operations for the suite of SRT first light receivers and backends continued in the following year, and was concluded with the first call for shared-risk early-science observations issued at the end of 2015. As discussed in the paper, the SRT capabilities were tested (and optimized when possible) for several different observing modes: imaging, spectroscopy, pulsar timing, and transients.

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An atmosphere monitoring system for the Sardinia radio telescope

Cited by 12 publications

References 11 publications

Spectropolarimetric observations of the CIZA J2242.8+5301 northern radio relic: no evidence of high-frequency steepening

Spectropolarimetric observations of the CIZA J2242.8+5301 northern radio relic: no evidence of high-frequency steepening

Investigating the high-frequency spectral features of SNRs Tycho, W44, and IC443 with the Sardinia Radio Telescope

The Sardinia Radio Telescope

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