The European Space Agency (ESA) will inaugurate its third Deep Space Antenna
(DSA 3) by the end of 2012. DSA 3 will be located in Argentina near the city of
Malarg"ue in the Mendoza province. While the instrument will be primarily
dedicated to communications with interplanetary missions, the characteristics
of its antenna and receivers will also enable standalone leading scientific
contributions, with a high scientific-technological return. We outline here
scientific proposals for a radio astronomical use of DSA 3.Comment: 4 pages, submitted as Proceedings for the BAA

Benaglia, P.

Casco, N.

Cichowolski, S.

Cillis, A.

de la Vega, G.

Garcia, B.

Ravignani, D.

Reynoso, E.

English

arXiv

The European Space Agency (ESA) will inaugurate its third Deep Space  Antenna (DSA 3) by the end of 2012. DSA 3 will be located in Argentina  near the city of Malarg"ue in the Mendoza province. While the instrument  will be primarily dedicated to communications with interplanetary  missions, the characteristics of its antenna and receivers will also  enable standalone leading scientific contributions, with a high  scientific-technological return. We outline here scientific proposals  for a radio astronomical use of DSA 3.Fil: Benaglia, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto Argentino de Radioastronomia (i); ArgentinaFil: Casco, N.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto Argentino de Radioastronomia (i); ArgentinaFil: Cichowolski, Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio(i); ArgentinaFil: Cillis, Analia Nilda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio(i); ArgentinaFil: Garcia, Beatriz Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnologías En Detección y Astropartículas; ArgentinaFil: Ravignani, D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnologías En Detección y Astropartículas; ArgentinaFil: Reynoso, Estela Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio(i); ArgentinaFil: de la Vega, G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnologías En Detección y Astropartículas; Argentin

Benaglia, Paula

Cichowolski, Silvina

Cillis, Analia Nilda

Garcia, Beatriz Elena

Reynoso, Estela Marta

CONICET Digital

Asociacio´n Argentina de Astronomı´aBAAA, Vol. 54, 2011J.J. Claria´, et al. eds.PRESENTACIO´N ORALThe antenna DSA 3 and its potential use for RadioAstronomyP. Benaglia1, N. Casco1, S. Cichowolski2, A. Cillis2, B. Garc´ıa3, D.Ravignani3, E. Reynoso2, G. de la Vega3(1) Instituto Argentino de Radioastronomı´a (IAR)(2) Instituto de Astronomı´a y F´ısica del Espacio (IAFE)(3) Instituto de Tecnolog´ıas en Deteccio´n y Astropart´ıculas (ITeDA)Abstract. The European Space Agency (ESA) will inaugurate its thirdDeep Space Antenna (DSA 3) by the end of 2012. DSA 3 will be lo-cated in Argentina near the city of Malargu¨e in the Mendoza province.While the instrument will be primarily dedicated to communications withinterplanetary missions, the characteristics of its antenna and receiverswill also enable standalone leading scientific contributions, with a highscientific-technological return. We outline here scientific proposals for aradio astronomical use of DSA 3.Resumen. La Agencia Espacial Europea (ESA) inaugurara´, a finalesde 2012, la tercera antena de espacio profundo (DSA 3), en suelo argen-tino (Malargu¨e, Mendoza). El instrumento se dedicara´ principalmente acomunicaciones con misiones interplanetarias. Dadas las caracter´ısticasde la antena y receptores, con la DSA 3 se podra´n realizar contribucionescient´ıficas de punta, con un alto retorno cient´ıfico-tecnolo´gico. Aqu´ı sedelinean propuestas cient´ıficas para su uso radioastrono´mico.1. IntroductionThe purpose of DSA 3 is to provide support to ESA interplanetary missions,like Mars Express, Venus Express, Rosetta, and the upcoming BepiColombo.DSA 3 will have an antenna of 35 m in diameter (D) and will work receivingand sending radio signals in two frequency bands, X and Ka (about 8 and 32GHz respectively). To make contact with missions typically located at three mil-lion kilometers and beyond, the use of low-noise amplifiers cooled to cryogenictemperatures is mandatory, along with highly accurate pointing and calibration.The facility will also have devices for tracking, telemetry modulation and demod-ulation, telecommand and data, radiometric and meteorological measurements.ESA already has two of these stations: DSA 1 in New Norcia (Australia)since 2002 and DSA 2 in Cebreros (Spain) since 2005. These antennas, alsoof D = 35 m, are currently the largest ones operated by ESA. DSA 3 willcomplement ESA deep-space network, ensuring around-the-clock coverage fortheir interplanetary missions. In return for harboring DSA 3 within its territory,ESA offers Argentina the use of up to 10% of the observing time, which will12represent an outstanding advantage for the local scientific community. Giventhe unique technical features of the instrument, this fraction of time can beutilized for first-level research in the radio astronomy field and in astrophysicsin general.2. Proposals for scientific use of the Deep Space Antenna 3The main instrumental parameters of DSA 3 are given in Table 11.Scientific proposals would be selected according to their academic excellence bypeer reviewers. The host country has researchers formed in Radio Astronomy,that can make an intensive use of DSA 3 and, simultaneously, train new radioastronomers using the facility. Studies on the sources mapped using DSA3 will be further deepen with the tremendous imaging resolution (< 1arcsec) of the forthcoming ALMA dishes at Band 1. Forefront researchlines that can be carried out during the host country observing time are presentedbelow.Observing bands; band centers (GHz) X ; 8.45 Ka; 32.05Bandwidths (MHz); Angular resolution (arcmin) 100; 4.4 200; 1.1Tsys(K); Expected (t=1s) continuum sensitivity (mK) 18; 1.8 30; 2.0Table 1. Main parameters of the instrument DSA 3.Unidentified gamma-ray sources. Last-generation gamma-ray telescopes,such as the FERMI satellite, and the H.E.S.S. I and II arrays (Namibia), con-tinuously monitor the southern sky and are detecting thousands of sources ofvery high energies (e.g., Fermi-LAT 2nd Source Catalog 2011 and Aharonian etal. 2008, respectively) with angular resolutions comparable to those of the DSAstations. An important part of the detected sources (∼ 30%) cannot be identi-fied as they do not have a counterpart in other energy ranges. The existence ofa physical relationship between radio and gamma-ray emission has been knownfor decades (Ginzburg & Syrovatskii 1965). DSA 3 will be a critical tool to de-termine the nature of the unidentified sources, and to study the processes thatcontribute to the radiation. Just to underline the importance of the subject, weremark the amount of resources allocated to instruments looking at high-energysources, the number of scientists commited to solve the underlying problems andthe amount of related articles published on a daily basis.The radio galaxy Centaurus A. Cen A harbors the closest supermassiveblack hole. However, its proximity implies a large source angular extension,which prevents us from observing it with radio interferometers at intermediatefrequencies (10 - 30 GHz, Israel 1998, Israel et al. 2008, etc). An instrumentlike DSA 3 can obtain data from all Centaurus A in a few days of observation.For the sake of comparison, the Australia Telescope Compact Array took about1Competitive facilites with similar observational capabilities, in Australia, are either over-suscribed -like the Parkes Telescope-, or have very restricted availability (NASA DSS43 &34, up to 200 h/yr) mostly attached to VLBI programs.32 years to map Cen A at 1.4 GHz (Feain et al. 2011). Observations at differentfrequencies could also provide information on the emission mechanisms. More-over, the study of the magnetic fields and the relativistic particles involved willbe possible by the fully polarimetric information that DSA 3 will supply.Variability of Active Galactic Nuclei. With DSA 3 it will be possibleto perform variability studies of brightness and polarization degree of ActiveGalactic Nuclei (AGN) emission in a very efficient way. Studies on time scalesof hours to years will report on the accretion process on the galaxy’s centralblack hole, still poorly known. Multi-frequency data from a large sample ofAGN will allow the study of the physical processes that support the variabilityof individual objects, and also of the differences between different classes of AGN(e.g., Hovatta et al. 2008, Gliozzi et al. 2009). The advantage of time seriesanalysis is that the information is gathered independently of the AGN type, andthat the results complement those found by means of spectroscopic studies.Supernova remnants and HII regions. The measuremet of the fluxes bothat the X and Ka bands can be used to discriminate the nature of the sourceobserved; in particular, SNRs and HII regions. Over 50% of the Galactic SNRsare above the limit of detectability offered by the DSA 3, even at 32 GHz. Forthose of larger angular size, it will be possible to study spatial variations ofthe spectral index and to measure directly the direction of the magnetic field.Parameters of the HII regions will be obtained from the measured fluxes, suchas the mass of ionized gas and the electron density. Ka-band observations willbe essential to elucidate, for example, why, although expected, there is no radiocontinuum emission towards a number of O-type stars, or how significant is thecontribution of the surrounding background emission to the measured flux.Physics and chemistry of proto-planetary clouds. Interstellar dark cloudsare the places where stars and planets are formed. The knowledge of their chem-ical composition is essential to understand how matter in the Universe evolvesto planets and life (e.g., Cernicharo et al. 2008). The study of these cloudshelps not only to determine chemical abundances, but also their growth (e.g.Ohishi & Kaifu 1998). The instruments used to date, besides having a veryhigh oversubscription, are all in the Northern Hemisphere (NRO Nobeyama-45m, 100-m Effeslberg, Onsala OSO-20m, IRAM-30m dishes), with a declinationlimit ∼ −250. In addition, the observing bands are above 75 GHz for all butNRO while DSA 3, in comparison, fills a niche covering 8 - 32 GHzbands . An instrument like DSA 3 will be ideal, and in many cases the only op-tion, to study southern dark clouds, given its great sensitivity, adequate angularresolution and fast coverage.“Flickering”and the interstellar medium. The interstellar material presentin the line of sight towards another galaxy, produces an effect of scintillation or“flickering” of the extragalactic radiation. The study of this phenomenon is animportant tool to gain information about the small scale inhomogeneities inthe electronic component of the interstellar medium (e.g., Bochkarev & Ryabov2000). The variability in brightness is produced by the refraction of light thattraverses, at high speed, a hot gas permeated by shock waves. Studies of vari-ability -in this case, extrinsic to the object- can be conducted in different timescales (days to years) with DSA 3.4Rotating radio transients. With DSA 3 it will also be possible to search fortransient events in radio waves just as with NASA deep space antennas (Buuet al. 2011). The so-called RRATs (Rotating RAdio Transients) have beenrecently discovered (McLoughlin et al. 2006, Lorimer et al. 2007) as sources ofvery intense pulses that may be of extragalactic origin. The physical descriptionof these rare objects is proving to be a challenge to such an extent that they areconsidered testers of basic physics and astrophysics.3. Scientific and technological returnThe excellent quality of the state of the art components of DSA 3 guarantees ben-efits to radio astronomy that are of great importance in leading areas. Since thebulk of the investment is provided by ESA, the use of DSA 3 for radio astronomyensures a maximum benefit/return to science and technology with a minimum ofcost/investment. Furthermore, observing during all the host country time willre-position Argentina as a world class player in the Radio Astronomy arena.Besides the advancement of the knowledge frontier in the outlined lines ofresearch, some of the additional benefits that can be attained through DSA 3include:• Insertion of Argentina in the radio astronomy research mainstream.• International collaborations with top-level groups.• Publication of results in international high-impact journals.• Training of technicians and engineers in the priority area of Informationand Communications Technologies (ICTs).• Training of scientists and engineers at graduate and postgraduate level.• Technological developments in electronic engineering and software.• Transfer of technology in communications, instrumentation and control,digital signal processing, frequency and time metrology.Acknowledgments. The authors are grateful to the ITeDA staff and toNora Loiseau. P.B. thanks support from PICT 2007-00848, ANPCyT. E.R. andS.C. are supported by UBA and CONICET grants.ReferencesAharonian et al. 2008, A&A, 353Bochkarev & Ryabov 2000, New Astron. Rev., 44, 375Buu et al. 2011, IEEE, 99, 5, 889Cernicharo et al. 2008, ApJ, L83Feain et al. 2011, ApJ, 740, 17Ginsburg & Syrovatskii 1965, ARA&A, 3, 297Gliozzi et al. 2009, ApJ, 703, 2215Hovatta et al. 2008, A&A, 485, 51Israel 1998, ARA&A, 8, 237Israel et al. 2008, A&A, 483, 741Lorimer et al. 2007, Science, 318, 777Mc Loughlin et al. 2006, Nature, 439, 817Ohishi & Kaifu 1998, Faraday Discussions No. 109, 205The Fermi-LAT Collaboration 2011, arXiv:1108.1435

The antenna DSA 3 and its potential use for Radio Astronomy

LAReferencia - Red Federada de Repositorios Institucionales de Publicaciones Científicas Latinoamericanas

Asociación Argentina de Astronomı́aBAAA, Vol. 54, 2011J.J. Clariá, et al. eds.PRESENTACIÓN ORALThe antenna DSA 3 and its potential use for RadioAstronomyP. Benaglia1, N. Casco1, S. Cichowolski2, A. Cillis2, B. Garćıa3, D.Ravignani3, E. Reynoso2, G. de la Vega3(1) Instituto Argentino de Radioastronomı́a (IAR)(2) Instituto de Astronomı́a y F́ısica del Espacio (IAFE)(3) Instituto de Tecnoloǵıas en Detección y Astropart́ıculas (ITeDA)Abstract. The European Space Agency (ESA) will inaugurate its thirdDeep Space Antenna (DSA 3) by the end of 2012. DSA 3 will be lo-cated in Argentina near the city of Malargüe in the Mendoza province.While the instrument will be primarily dedicated to communications withinterplanetary missions, the characteristics of its antenna and receiverswill also enable standalone leading scientific contributions, with a highscientific-technological return. We outline here scientific proposals for aradio astronomical use of DSA 3.Resumen. La Agencia Espacial Europea (ESA) inaugurará, a finalesde 2012, la tercera antena de espacio profundo (DSA 3), en suelo argen-tino (Malargüe, Mendoza). El instrumento se dedicará principalmente acomunicaciones con misiones interplanetarias. Dadas las caracteŕısticasde la antena y receptores, con la DSA 3 se podrán realizar contribucionescient́ıficas de punta, con un alto retorno cient́ıfico-tecnológico. Aqúı sedelinean propuestas cient́ıficas para su uso radioastronómico.1. IntroductionThe purpose of DSA 3 is to provide support to ESA interplanetary missions,like Mars Express, Venus Express, Rosetta, and the upcoming BepiColombo.DSA 3 will have an antenna of 35 m in diameter (D) and will work receivingand sending radio signals in two frequency bands, X and Ka (about 8 and 32GHz respectively). To make contact with missions typically located at three mil-lion kilometers and beyond, the use of low-noise amplifiers cooled to cryogenictemperatures is mandatory, along with highly accurate pointing and calibration.The facility will also have devices for tracking, telemetry modulation and demod-ulation, telecommand and data, radiometric and meteorological measurements.ESA already has two of these stations: DSA 1 in New Norcia (Australia)since 2002 and DSA 2 in Cebreros (Spain) since 2005. These antennas, alsoof D = 35 m, are currently the largest ones operated by ESA. DSA 3 willcomplement ESA deep-space network, ensuring around-the-clock coverage fortheir interplanetary missions. In return for harboring DSA 3 within its territory,ESA offers Argentina the use of up to 10% of the observing time, which will12represent an outstanding advantage for the local scientific community. Giventhe unique technical features of the instrument, this fraction of time can beutilized for first-level research in the radio astronomy field and in astrophysicsin general.2. Proposals for scientific use of the Deep Space Antenna 3The main instrumental parameters of DSA 3 are given in Table 11.Scientific proposals would be selected according to their academic excellence bypeer reviewers. The host country has researchers formed in Radio Astronomy,that can make an intensive use of DSA 3 and, simultaneously, train new radioastronomers using the facility. Studies on the sources mapped using DSA3 will be further deepen with the tremendous imaging resolution (< 1arcsec) of the forthcoming ALMA dishes at Band 1. Forefront researchlines that can be carried out during the host country observing time are presentedbelow.Observing bands; band centers (GHz) X ; 8.45 Ka; 32.05Bandwidths (MHz); Angular resolution (arcmin) 100; 4.4 200; 1.1Tsys(K); Expected (t=1s) continuum sensitivity (mK) 18; 1.8 30; 2.0Table 1. Main parameters of the instrument DSA 3.Unidentified gamma-ray sources. Last-generation gamma-ray telescopes,such as the FERMI satellite, and the H.E.S.S. I and II arrays (Namibia), con-tinuously monitor the southern sky and are detecting thousands of sources ofvery high energies (e.g., Fermi-LAT 2nd Source Catalog 2011 and Aharonian etal. 2008, respectively) with angular resolutions comparable to those of the DSAstations. An important part of the detected sources (∼ 30%) cannot be identi-fied as they do not have a counterpart in other energy ranges. The existence ofa physical relationship between radio and gamma-ray emission has been knownfor decades (Ginzburg & Syrovatskii 1965). DSA 3 will be a critical tool to de-termine the nature of the unidentified sources, and to study the processes thatcontribute to the radiation. Just to underline the importance of the subject, weremark the amount of resources allocated to instruments looking at high-energysources, the number of scientists commited to solve the underlying problems andthe amount of related articles published on a daily basis.The radio galaxy Centaurus A. Cen A harbors the closest supermassiveblack hole. However, its proximity implies a large source angular extension,which prevents us from observing it with radio interferometers at intermediatefrequencies (10 - 30 GHz, Israel 1998, Israel et al. 2008, etc). An instrumentlike DSA 3 can obtain data from all Centaurus A in a few days of observation.For the sake of comparison, the Australia Telescope Compact Array took about1Competitive facilites with similar observational capabilities, in Australia, are either over-suscribed -like the Parkes Telescope-, or have very restricted availability (NASA DSS43 &34, up to 200 h/yr) mostly attached to VLBI programs.32 years to map Cen A at 1.4 GHz (Feain et al. 2011). Observations at differentfrequencies could also provide information on the emission mechanisms. More-over, the study of the magnetic fields and the relativistic particles involved willbe possible by the fully polarimetric information that DSA 3 will supply.Variability of Active Galactic Nuclei. With DSA 3 it will be possibleto perform variability studies of brightness and polarization degree of ActiveGalactic Nuclei (AGN) emission in a very efficient way. Studies on time scalesof hours to years will report on the accretion process on the galaxy’s centralblack hole, still poorly known. Multi-frequency data from a large sample ofAGN will allow the study of the physical processes that support the variabilityof individual objects, and also of the differences between different classes of AGN(e.g., Hovatta et al. 2008, Gliozzi et al. 2009). The advantage of time seriesanalysis is that the information is gathered independently of the AGN type, andthat the results complement those found by means of spectroscopic studies.Supernova remnants and HII regions. The measuremet of the fluxes bothat the X and Ka bands can be used to discriminate the nature of the sourceobserved; in particular, SNRs and HII regions. Over 50% of the Galactic SNRsare above the limit of detectability offered by the DSA 3, even at 32 GHz. Forthose of larger angular size, it will be possible to study spatial variations ofthe spectral index and to measure directly the direction of the magnetic field.Parameters of the HII regions will be obtained from the measured fluxes, suchas the mass of ionized gas and the electron density. Ka-band observations willbe essential to elucidate, for example, why, although expected, there is no radiocontinuum emission towards a number of O-type stars, or how significant is thecontribution of the surrounding background emission to the measured flux.Physics and chemistry of proto-planetary clouds. Interstellar dark cloudsare the places where stars and planets are formed. The knowledge of their chem-ical composition is essential to understand how matter in the Universe evolvesto planets and life (e.g., Cernicharo et al. 2008). The study of these cloudshelps not only to determine chemical abundances, but also their growth (e.g.Ohishi & Kaifu 1998). The instruments used to date, besides having a veryhigh oversubscription, are all in the Northern Hemisphere (NRO Nobeyama-45m, 100-m Effeslberg, Onsala OSO-20m, IRAM-30m dishes), with a declinationlimit ∼ −250. In addition, the observing bands are above 75 GHz for all butNRO while DSA 3, in comparison, fills a niche covering 8 - 32 GHzbands . An instrument like DSA 3 will be ideal, and in many cases the only op-tion, to study southern dark clouds, given its great sensitivity, adequate angularresolution and fast coverage.“Flickering”and the interstellar medium. The interstellar material presentin the line of sight towards another galaxy, produces an effect of scintillation or“flickering” of the extragalactic radiation. The study of this phenomenon is animportant tool to gain information about the small scale inhomogeneities inthe electronic component of the interstellar medium (e.g., Bochkarev & Ryabov2000). The variability in brightness is produced by the refraction of light thattraverses, at high speed, a hot gas permeated by shock waves. Studies of vari-ability -in this case, extrinsic to the object- can be conducted in different timescales (days to years) with DSA 3.4Rotating radio transients. With DSA 3 it will also be possible to search fortransient events in radio waves just as with NASA deep space antennas (Buuet al. 2011). The so-called RRATs (Rotating RAdio Transients) have beenrecently discovered (McLoughlin et al. 2006, Lorimer et al. 2007) as sources ofvery intense pulses that may be of extragalactic origin. The physical descriptionof these rare objects is proving to be a challenge to such an extent that they areconsidered testers of basic physics and astrophysics.3. Scientific and technological returnThe excellent quality of the state of the art components of DSA 3 guarantees ben-efits to radio astronomy that are of great importance in leading areas. Since thebulk of the investment is provided by ESA, the use of DSA 3 for radio astronomyensures a maximum benefit/return to science and technology with a minimum ofcost/investment. Furthermore, observing during all the host country time willre-position Argentina as a world class player in the Radio Astronomy arena.Besides the advancement of the knowledge frontier in the outlined lines ofresearch, some of the additional benefits that can be attained through DSA 3include:• Insertion of Argentina in the radio astronomy research mainstream.• International collaborations with top-level groups.• Publication of results in international high-impact journals.• Training of technicians and engineers in the priority area of Informationand Communications Technologies (ICTs).• Training of scientists and engineers at graduate and postgraduate level.• Technological developments in electronic engineering and software.• Transfer of technology in communications, instrumentation and control,digital signal processing, frequency and time metrology.Acknowledgments. The authors are grateful to the ITeDA staff and toNora Loiseau. P.B. thanks support from PICT 2007-00848, ANPCyT. E.R. andS.C. are supported by UBA and CONICET grants.ReferencesAharonian et al. 2008, A&A, 353Bochkarev & Ryabov 2000, New Astron. Rev., 44, 375Buu et al. 2011, IEEE, 99, 5, 889Cernicharo et al. 2008, ApJ, L83Feain et al. 2011, ApJ, 740, 17Ginsburg & Syrovatskii 1965, ARA&A, 3, 297Gliozzi et al. 2009, ApJ, 703, 2215Hovatta et al. 2008, A&A, 485, 51Israel 1998, ARA&A, 8, 237Israel et al. 2008, A&A, 483, 741Lorimer et al. 2007, Science, 318, 777Mc Loughlin et al. 2006, Nature, 439, 817Ohishi & Kaifu 1998, Faraday Discussions No. 109, 205The Fermi-LAT Collaboration 2011, arXiv:1108.1435

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The antenna DSA 3 and its potential use for Radio Astronomy

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