Characterization of the atmosphere above a site for millimeter wave astronomy

Nasir, Francesco; Buffa, Franco; Deiana, Gian Luigi

doi:10.1007/s10686-011-9214-9

Cited by 6 publications

(6 citation statements)

References 11 publications

(10 reference statements)

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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%

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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Section: Resultsmentioning

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 AMS uses data sets coming from local sensors, such as the SRT Microwave Radiometer 5 (SMR) and the in situ SRT Weather Stations (SWS), from a Regional GPS Network (SARNET) managed by a private company 6 , and finally from an Airport 7 Radio Sounding (ARS) site to perform a realtime monitoring of the atmosphere status, see top panel in figure 2. All measured and derived data, i.e.…”

Section: Atmosphere Monitoring Systemmentioning

confidence: 99%

“…Recently, we made a statistical study considering a long dataset of radio soundings [7], which gave useful informa tion on which period of the year and of the day astronomical observations at different frequencies should be preferably performed.…”

Section: Radiosondesmentioning

confidence: 99%

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An atmosphere monitoring system for the Sardinia radio telescope

Buffa

Bolli

Sanna

et al. 2016

Meas. Sci. Technol.

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The Sardinia Radio Telescope (SRT) is a new facility managed by the Italian National Institute for Astrophysics (INAF). SRT will detect the extremely faint radio wave signals emitted by astronomical objects in a wide frequency range from decimeter to millimeter wavelengths. Especially at high frequencies (>10 GHz), bad weather conditions and interactions between signal and atmospheric constituents (mainly water and oxygen molecules) can strongly affect the radio astronomic observation reducing the antenna performances, for instance, increasing the pointing error or decreasing the sensitivity. Thus, modern ground-based telescopes are usually equipped with systems able to examine in real-time several atmospheric parameters (opacity, integrated water vapor, etc.), and in some cases to forecast the weather conditions (wind, rain, snow, etc.), in order to ensure the antenna safety and support the schedule of the telescope observations. Here, we describe the Atmosphere Monitoring System (AMS) realized with the aim to improve the SRT operative efficiency. It consists of a network of different sensors such as radiometers, radiosondes, weather stations, GPS and some well-established weather models. After a validation of the scheme, we successfully tested the AMS in two real practical scenarios, comparing the AMS outcomes with those of independent techniques. In the first one we were able to detect an incoming storm front applying different techniques (GPS, radiometer and the weather forecast model), while in the last one we modeled the SRT antenna system temperature at 22 GHz processing the AMS data set.

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“…The average PWV in the same conditions is mainly 8 mm. 50 years of radiosonde profiles taken at Cagliari airport (30 km far, at sea level) and scaled for SRT site shows PWV < 11 mm (50 th percentile) and opacity < 0.2 (50 th percentile) at 100 GHz [11]. What mainly concern W-band measurement a dynamic scheduling will be applied to optimize the observational time and weather conditions.…”

Section: Site Conditionmentioning

confidence: 99%

Millimetric Sardinia radio Telescope Receiver based on Array of Lumped elements kids

et al. 2022

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MISTRAL is a millimetric camera working in the W-band (78–103 GHz) which will take data from the Sardinia Radio Telescope, the Italian 64-m radio telescope located 50 km form Cagliari, at 600m above the sea level, in Sardinia. It is being built as a facility instrument by the Sapienza University for INAF, that manages the radio telescope, under a PON contract. It will consist of a compact cryostat hosting the re–imaging optics, cooled at 4K, and a 408–pixel array of photon–noise limited lumped element kinetic inductance detectors fabricated at CNR-IFN and cooled at a base temperature lower than 300mK. MISTRAL will be able to investigate a long list of scientific targets spanning from extragalactic astrophysics to solar system science, with high angular resolution (~ 12 arcsec), including Sunyaev Zel’dovich effect measurements and the study of the Cosmic Web.

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Characterization of the atmosphere above a site for millimeter wave astronomy

Cited by 6 publications

References 11 publications

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

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

An atmosphere monitoring system for the Sardinia radio telescope

Millimetric Sardinia radio Telescope Receiver based on Array of Lumped elements kids

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