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Pranusanguni - San Basilio (Cagliari) Italy

Astronomers

Science with SRT

 

 Published Papers:

 

Single-dish and VLBI observations of Cygnus X-3 during the 2016 giant flare episode

(Monthly Notices of the Royal Astronomical Society, 2017, accepted)

by E. Egron, A. Pellizzoni, M. Giroletti, S. Righini, M. Stagni, A. Orlati, C. Migoni, A. Melis, L. Barbas, S. Buttaccio, P. Cassaro, P. De Vicente, M.P. Gawronski, M. Lindqvist, G. Maccaferri, C. Stanghellini, P. Wolak, J. Yang, A. Navarrini, S. Loru, M. Pilia, M. Bachetti, M.N. Iacolina, M. Buttu, S. Corbel, J. Rodriguez, S. Markoff, J. Wilms, K. Pottschmidt, M. Cadolle Bel, E. Kalemci, T. Belloni, V. Grinberg, M. Marongiu, G.P. Vargiu, A. Trois

In September 2016, the microquasar Cygnus X-3 underwent a giant radio flare, which was monitored for 6 days with the Medicina Radio Astronomical Station and the Sardinia Radio Telescope. Long observations were performed in order to follow the evolution of the flare on a hourly scale, covering six frequency ranges from 1.5 GHz to 25.6 GHz. Rapid flux variations were observed at high radio frequencies at the peak of the flare, together with rapid evolution of the spectral index. This is the first time that such fast variations are observed. Based on the Italian network (Noto, Medicina and SRT) and extended to the European antennas (Torun, Yebes, Onsala), VLBI observations were triggered at 22 GHz on five different occasions, four times prior to the giant flare, and once during its decay phase. Flux variations of 2-hour duration were recorded.

  

Imaging of SNR IC443 and W44 with the Sardinia Radio Telescope at 1.5 GHz and 7 GHz

(Monthly Notices of the Royal Astronomical Society, Volume 470, Issue 2, p.1329-1341, 2017)

by E. EgronA. PellizzoniM. N. IacolinaS. LoruM. MarongiuS. RighiniM. CardilloA. GiulianiS. MulasG. MurtasD. SimeoneR. ConcuA. MelisA. TroisM. PiliaA. NavarriniV. VaccaR. RicciG. SerraM. BachettiM. ButtuD. PerrodinF. BuffaG. L. DeianaF. GaudiomonteA. FaraA. LaduF. LoiP. MarongiuC. MigoniT. PisanuS. PoppiA. SabaE. UrruG. ValenteG.P. Vargiu

Observations of supernova remnants (SNRs) are a powerful tool for investigating the later stages of stellar evolution, the properties of the ambient interstellar medium, and the physics of particle acceleration and shocks (Cosmic Rays production). Although radio emission is a prime probe for refining models, high-resolution images at frequencies above 5 GHz are surprisingly lacking. In the frameworks of the Early Science Program with the SRT, we provided, for the first time, single-dish deep imaging at 7 GHz of the SNR IC443 and W44 complexes coupled with spatially-resolved spectra in the 1.5-7 GHz frequency range. Our images were obtained through on-the-fly mapping techniques, providing antenna beam oversampling and resulting in accurate continuum flux density measurements.

 

Sardinia Radio Telescope observations of Abell 194 - the intra-cluster magnetic field power spectrum (Astronomy & Astrophysics, 2017,  603, A122)

by F. Govoni, M. Murgia, V. Vacca, F. Loi, M. Girardi, F. Gastaldello, G. Giovannini, L. Feretti, R. Paladino, E. Carretti, R. Concu, A. Melis, S. Poppi, G. Valente, G. Bernardi, A. Bonafede, W. Boschin, M. Brienza, T.E. Clarke, S. Colafrancesco, F. de Gasperin, D. Eckert, T.A. Ensslin, C. Ferrari, L. Gregorini, M. Johnston-Hollitt, H. Junklewitz, E. Orru', P. Parma, R. Perley, M. Rossetti, G.B Taylor, F. Vazza

This work focuses on the study of the intra-cluster magnetic field in the poor galaxy cluster Abell 194. New total intensity and polarization observations of Abell 194 obtained with the Sardinia Radio Telescope were combined with archival Very Large Array observations to derive the spectral aging and the rotation measure images of the radio galaxies 3C40A and 3C40B embedded in the cluster. These data in combination with X-ray images are used to constrain the intra-cluster magnetic field properties. To date, the central magnetic field derived for Abell 194 is the weakest ever found using rotation measure data in galaxy cluster.

 

Planar infall of CH3OH gas around Cepheus A HW2 (Astronomy & Astrophysics, 2017, in press)

by A. Sanna, L. Moscadelli, G. Surcis, H.J. van Langevelde, K.J.E. Torstensson, A.M. Sobolev

To test the nature of an (accretion) disk in the vicinity of Cepheus A HW2, the three-diemnsional velocity field of methanol maser spots was measured with an accuracy of the order of 0.1 km/s. The source was observed with the European VLBI Network (EVN) for three epochs spaced by one year between 2013 and 2015. During last epoch the observations benefited from the new deployed Sardinia Radio Telescope.

 

Sardinia Radio Telescope wide-band spectral-polarimetric observations of the galaxy cluster 3C129

(Monthly Notices of the Royal Astronomical Society, Volume 461, Issue 4, p.3516-3532, 2016)

by M. Murgia, F. Govoni, E. Carretti, A. Melis, R. Concu, A. Trois, F. Loi, V. Vacca, A. Tarchi, P. Castangia, A. Possenti, A. Bocchinu, M. Burgay, S. Casu, A. Pellizzoni, T. Pisanu, A. Poddighe, S. Poppi, N. D'Amico, M. Bachetti, A. Corongiu, E. Egron, N. Iacolina, A. Ladu, P. Marongiu, C. Migoni, D. Perrodin, M. Pilia, G. Valente, G. Vargiu

This paper presents the results of the commissioning of the ROACH2-based backend at the Sardinia Radio Telescope. New observations of the galaxy cluster 3C129 in the frequency range 6000-7200 MHz are used to image the large-angular-scale emission at high-frequency of the radio sources located in this cluster of galaxies, including the tailed radio galaxy 3C129 at its center. These data were used, in combination with literature data at lower frequencies, to derive the variation of the synchrotron spectrum of 3C129 along the tail of the radio source in order to infer its radiative age and its speed.


 

The Sardinia Radio Telescope: From a Technological Project to a Radio Observatory (Astronomy & Astrophysics, 2017, in press)

by I. PrandoniM. MurgiaA. TarchiM. BurgayP. CastangiaE. EgronF. GovoniA. PellizzoniR. RicciS. RighiniM. BartoliniS. CasuA. CorongiuM. N. IacolinaA. MelisF. T. NasirA. OrlatiD. PerrodinS. PoppiA. TroisV. VaccaA. ZanichelliM. BachettiM. ButtuG. ComorettoR. ConcuA. FaraF. GaudiomonteF. LoiC. MigoniA. OrfeiM. PiliaP. BolliE. CarrettiN. D'AmicoD. GuidettiS. LoruF. MassiT. PisanuI. PorcedduA. RidolfiG. SerraC. StanghelliniC. TiburziS. TingayG. Valente

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 SRT's scientific capabilities. 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: European VLBI Network and Large European Array for Pulsars (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 years, and was concluded with the first call for shared-risk/early-science observations issued at the end of 2015.


Astronomer's Telegrams:


Monitoring of Cyg X-3 giant flare with Medicina and the Sardinia Radio Telescope (ATel #9508)

 by E. Egron, A. Pellizzoni, M. Giroletti, S. Righini, A. Orlati, M. N. Iacolina, A. Navarrini, M. Buttu, C. Migoni, A. Melis, R. Concu, G. P. Vargiu, M. Bachetti, M. Pilia, A. Trois, S. Loru, M. Marongiu


Detection of a bright radio flare of Cygnus X-1 at 7.2 GHz with the Sardinia Radio Telescope (ATel #9087)

by E. Egron, A. Pellizzoni, M. Bachetti, A. Navarrini, A. Trois, M. Pilia, M. N. Iacolina, A. Melis, R. Concu, S. Loru, A. Sessini, V. Grinberg, M. Nowak, S. Markoff, K. Pottschmidt, J. Rodriguez, J. Wilms, R. Ballhausen, S. Corbel, W. Eikmann, F. Fuerst, I. Kreykenbohm, M. Marongiu, A. Possenti 

 

 Detection of GRS 1915+105 and SS 433 at 7.2 GHz and 21.4 GHz with the Sardinia Radio Telescope (ATel #8921)

 by E. Egron, A. Pellizzoni, M. Bachetti, A. Navarrini, A. Trois, M. Pilia, M. N. Iacolina, A. Melis, R. Concu, S. Loru, R. Ballhausen, S. Corbel, W. Eikmann, F. Fuerst, V. Grinberg, I. Kreykenbohm, M. Marongiu, M. Nowak, A. Possenti, K. Pottschmidt, J. Rodriguez, J. Wilms

 

 Observations of H1743-322 with the Sardinia Radio Telescope: upper limits (ATel #8849)

by E. Egron, M. Bachetti, A. Pellizzoni, A. Trois, M. N. Iacolina, M. Pilia, S. Loru, A. Navarrini, R. Ballhausen, S. Corbel, W. Eikmann, F. Fuerst, V. Grinberg, I. Kreykenbohm, M. Marongiu, M. Nowak, A. Possenti, K. Pottschmidt, J. Rodriguez, J. Wilms

 

Sardinia Radio Telescope observations of IGR J17091-3624 - upper limit (ATel #8821)

by E. Egron, M. Pilia, M. Bachetti, M. N. Iacolina, A. Pellizzoni, A. Trois, S. Loru, A. Navarrini, R. Ballhausen, S. Corbel, W. Eikmann, F. Fuerst, V. Grinberg, I. Kreykenbohm, M. Marongiu, M. Nowak, A. Possenti, K. Pottschmidt, J. Rodriguez, J. Wilms


Detection by Sardinia Radio Telescope of radio pulses at 7 GHz from the Magnetar PSR J1745-2900 in the Galactic center region (ATel #5053)

by M. Buttu, N. D'Amico, E. Egron, M. N. Iacolina, P. Marongiu, C. Migoni, A. Pellizzoni, S. Poppi, A. Possenti, A. Trois, G. P. Vargiu, on behalf of the Sardinia Radio Telescope Science Validation Team and the Commissioning Team

 

List of approved SRT Early Science Projects in 2016

 

SRT in the VLBI Networks

The Large European Array for Pulsars (LEAP Project)