Livio Scarsi: 60 years of scientific activity dedicated to Physics, Cosmic Rays and High Energy Astrophysics from Space.

(B. Sacco, 6th Intnl Workshop of the “Data Analysis in Astronomy, Livio Scarsi, 15-22 April 2007, Erice, Italy ) The reach scientific career of Livio Scarsi starts at Genoa University, as physics student in the Institute of Augusto Occhialini father of Beppo Occhialini. On 1950’ Livio took the degree in physics discussing a thesis on “ Cosmic Radiation Soft Electromagnetic Component at Pic du Midi : Investigation with nuclear emulsions “ . Tutor : Giuseppe (Beppo) Occhialini . “ During the studies in Genoa he had, also, the opportunity to know Bruno Rossi. Beppo Occhialini and Bruno Rossi are the reference points in the scientific life of Livio. From memories of Livio:

Bruno Rossi and Beppo Occhialini Artistic photo composition by A. Spizzichino, “The Active X-ray Sky”, 21-24 October, 1997, Roma A. Watson, Intl. Workshop “ The UHE Universe”, Villa Mondragone, Frascati,19-21 June,2006 In 1952 Livio follows Beppo Occhialini in Milan and in 1955 Beppo send Livio in France, at the Centre d’Etudes Nucleaires de Saclay where he remains for 3 years: researches for “New Particles” in the Cosmic Radiation with the tecnique of Nuclear Emulsions flown in the Upper Atmosphere with Stratospheric Balloons. Relevant results are : First classification of Decay modes for K-mesons and Hyperons In 1957 he comes back in Milan but …..

From memories of Livio:

“A. Watson, UHE Workshop , Villa Mondragone, Frascati, June 21, 2006.” Volcano Ranch , “ The desert Quinn”

In Volcano Ranch, New Mexico desert, Jonh Linsley and Livio Scarsi installed 19 plastic scintillators (3.3 m2 area each-one) in an exagone of about 2,430,000 m2 area. Scintillators are coupled with fotomultipliers and oscilloscopes controlled by photo -cameras.

Among many observed showers one contains more than 30 billions particles corresponding to a primary particle energy of 6 x 1019 eV. From memories of Livio Scarsi

“A. Watson, UHE Workshop , Villa Mondragone, Frascati, June 21, 2006.”

A part a brief period (1981-1983) in which he had the Chair of Space Physics at the University of Rome, La Sapienza, Livio Scarsi remains in Palermo as Professor of Advanced Physics and General Physics. In Palermo he establishes the High Energy Astro-Physics research group from which originates the Istituto di Fisica Cosmica con Applicazioni all’Informatica /CNR now Istituto di Astrofisica Spaziale e Fisica Cosmica/INAF. The scientific activity of Livio Scarsi since 1961 to 2000 is manly devoted to Astrophysics from Space: Cosmic Rays, X and Gamma-ray Astronomy. Its activity concerns proposals, implementation and scientific driving of space missions in a the framework of the international Space community, participating as main actor.

Researches on rare components of the Cosmic Radiation with detectors on board of stratospheric balloons and rockets. The ESRO/ESA COS-B gamma-ray mission. Proposal to NASA of a Spark Chamber alternative to the one of EGRET/GRO. Participation to the ESA experiment Space-lab on the Shuttle. The French-Italian Gamma Ray balloon experiment, FIGARO. The Italian satellite SAX.

Contribution to the ESA EXOSAT mission . The Russian mission SPECTRUM X-Gamma with the British/Italian JET-X Telecsope Extreme Universe Space Observatory, EUSO 1961 – 1974, Research on rare components of the Cosmic Radiation with detectors on board of stratospheric balloons and rockets.

9First experiment in Italy with a Rocket in the Program of the European Space Research Organization – ESRO

9Extensive use and improvement of the Stratosferic Balloon Technique. 9Establishement of a Balloon Launch Facility in Sicily at Trapani Birgi (operated by Palermo group); after transferred to Trapani Milo and now operated by the Italian Space Agency ASI. Relevant results:

• Measurement of the albedo flux of low energy neutrons from Earth and of their Latitude effect.

• Discovery and flux measurement of Primary electron with energy above several GeV and measurement of the ratio e+ / e- .

• FIRST detection of Pulsed emission of Gamma Radiation above 50 MeV from the Crab Nebula Pulsar PSR0531+21.

COS_B is the name of a The feasibility study of the cosmic ray satellite successful space mission was realised in ESTEC by a group of European aimed at studying celestial scientists (L. Scarsi, M. Sommer, H. Martin, R. gamma rays. Pacault, J. van Boeckel, J. Ortner, Feasibility It was carried out by a team of study of a cosmic ray satellite, ESRO SP-23, European scientists within the August 1967). framework of the scientific The group presented two possible alternatives: programme of the European COS-A an heavy low orbit satellite Space Organization (ESRO) COS-B an highly eccentric orbit satellite. first and of the European Space Agency later. The second option, COS-B, lighter and less expensive respect to the first-one, competed with other projects as GEOS for studies of terrestrial plasma and UVAS for UV astronomy.

At the end of a two years discussions (1969), ESRO adopted COS-B and GEOS. COS-B is the first example of the establishment of the “big science” in space research in Europe.

Many scientists involved in the construction of the scientific payload of COS-B and in the analysis of its data were widely distributed in space and time spread as they over six laboratories calling themselves the Caravane Collaboration,in four countries and over three scientific generations. Livio Scarsi and Klaus Pinkau linked between the old group of the proponents, Labeyrie for France, Lust for Germany, Trendelenburg for ESRO/ESTEC and Occhialini for Italy and the following younger generation who carried on the mission and data analysis until the end.

COS-B provided a continuous flow of useful data from August 1975 until April 1982, when the instruments on board were switched off because of irreversible deterioration of the spark chamber due to the consumption of the gas. COS-B gave a fundamental contribution to the field of gamma-ray astronomy, dramatically improving the available data base from about 8000 gamma-ray events (manly from the NASA SAS-2 mission) to more than 200.000 events in the range from 50 MeV to 5 GeV. the first gamma-ray map of the milk way in three different energy bands (Mayer-Hasselwander et al., Astronomy & Astrophysics, 105, 1982);

COS-B provided the first complete map of the Galaxy in gamma-rays the first catalogue of discrete sources (25 sources), ( Swanenburg et al., Astrophysical Journal, 243, 1981);

the first extragalactic source emitting gamma-ray (the AGN 3C273), Swanenburg et al., Astrophysical Journal, 243, 1981; Bignami et al., Astron. Astrophys, 93, 1981 detailed studies of gamma-ray emission from radio-pulsar (Crab, Vela,.. and other pulsars)

Main references: Kanbach et al. Astron. Astrophys. 90, 1980; Wills et al., Nature, 5859, 1982; Buccheri et al. Astron.Astrophys. 128, 1983. SAX (Satellite for Astronomy X) was presented to National Space Plan by Livio Scarsi et al., following an AO for an Italian national scientific mission in 1981. SAX was in competition with OCSA presented by R. Giacconi. A senior committee (E. Amaldi, G. Occhialini, B.Rossi) selected SAX in 1982 for a launch planned in 1988 by a Shuttle with the PAM (Paylod Assisted Module) provided by the Italian IRIS. The program has been cancelled at mid 1987 due to the Challenger disaster (January 1986).

Due to the strong and resolute activity of Livio Scarsi, the mission has been re- oriented towards an Expendable Launch Vehicle.

SAX, now BeppoSAX, so named in honour of Giuseppe “Beppo” Occhialini, “maestro” of Livio has been launched on April, 30, 1996 at 04:31 GMT, with an Atlas-Centaur. Livio Scarsi leaded the mission until the end, 6 years up to April 30, 2002. BeppoSAX Launch: 30 April 1996 04:31 GMT BeppoSAX

The scientific payload: • LECS, Low Energy Concentrator Spectrometer (0.1 – 10 keV), by SSD/ESA-ESTEC • MECS, three units, Medium Energy Concentrator Spectrometer (1.3-10 keV), by IFCTR (Milan) and IFCAI (Palermo) • HPGSPC, High Pressure Gas Scintillation Proportional Counter (4-120 keV), by IFCAI (Palermo) • PDS, Phoswich Detector System (15-300 keV) and its lateral shields as GRBM (60-600 keV), by TESRE (Bologna) and IAS (Roma) • WFC, two units, Wide Field Camera (2-30 keV), by SRON, Netherland.

Special features: BeppoSAX was the first X-ray mission with a scientific payload covering more than three decades of energy with a relatively large effective area, medium energy resolution and imaging capabilities in the range of 0.1-10 keV. BeppoSAX scientific highligths

The large energy band (0.1-200 keV), the imaging capability (in the range 0.1-10 keV), the presence of narrow field instruments < ~1° together with wide field instruments ~ 40° allowed to perform: • broad band spectral observation of different classes of X-ray sources, • spatial resolved spectroscopy, • time/phase resolved spectroscopy, • detection of transient phenomena with WFC and studying them with the most sensitive NFI, • first arc-minutes position of GRBs. Position determination on rapid scale time, • first X-ray follow-up observations and monitoring of the GRBs.

Beppo-SAX has been operated as an observatory. Hundreds of scientists in the world observed the x-ray sky with BeppoSAX and more than 1500 scientific publications have appeared in the literature. These BeppoSAX MECS images and the plot to the right show the luminosity evolution of the Soft X-ray Transient Aql X-1, a binary system including a and a "normal" K star. The detection of Aql X-1 in outburst by the RXTE satellite (green points) triggered a series of BeppoSAX observations (red points) which allowed the investigators for the first time to follow the X-ray emission evolution down to a quiescence phase. Courtesy of S. Campana, Brera Observatory, Milano-Mera Time dependent spectral behaviour of the binary system 4U 1630-472

Courtesy of A. Segreto, IFCAI/CNR-Palermo The BeppoSAX observation of eight binary pulsars led to the detection of cyclotron lines in six of them. In three cases (the 4.8 sec high-mass X-ray pulsar Cen X-3; the 7.7 sec low-mass X-ray binary pulsar4U1626-67; and the 700 sec high-mass X-ray pulsar GX301-2) such features were never observed before.The broad-band spectrum of 4U1626-67 is shown on the left side. The figure on the right shows the spectra of the eight pulsars divided by the spectrum of the Crab Nebula, a technique that is used to visualize spectral features such as cyclotron lines. Courtesy of M. Orlandini and D. Dal Fiume, TeSRE Institute, CNR,Bologna, Italy. Phase resolved spectroscopy: Discovery of the higher cyclotron arbsorption harmonics of the X-ray binary pulsar X0115+63

Courtesy of A. Santangelo, A.Segreto, IFCAI/CNR Palermo, Italy Left: Mosaic of BeppoSAX MECS images of the central region of our Galaxy in the 2-10 keV energy range.Several bright compact sources, consisting of neutron stars and black holes accreting in binary systems, are concentrated in this region of the Galaxy. Courtesy of S.Mereghetti and L.Sidoli, IFC"G.Occhialini", CNR, Milano, Italy. Right: BeppoSAX Wide Field Camera image of the Galactic plane region. A constellation of X- ray binary sources within the very large field of view (only partly shown) of this coded mask instrument trace the Galactic plane. Courtesy of L. Natalucci, IAS/CNR, Rome, Italy, J.Schuurmans, SRON, Utrecht, and J. M. Muller, BeppoSAX SDC The image mosaic to the left has been constructed using data from the BeppoSAX X-ray telescopes (LECS and MECS). It shows several X-ray pulsars found in the nearby galaxy known as the Small Magellanic Cloud. The power spectrum and folded light-curve shown on the right side refer to the recently discovered pulsar 1SAX J0103.2-7209. Courtesy of G. Israel, Oss. Astr. di Roma-Monteporzio, Italy. A BeppoSAX observation of Nova Velorum 1999: A very bright classical Nova. Orio et al. MNRAS 362 130,2001

LECS images of Nova Velorum in June and in November 1999 Wide-band X-ray spectrum and 2-10 keV lightcurve of AB Doradus and Algol, a rapidly rotating young star and an eclipsing binary system. Large flare events, followed for their entire duration, were detected in both cases. These observations show for the first time that hard X-ray emission (>20 keV) is produced during stellar flares. Courtesy of R. Pallavicini, Palermo Observatory, G. Tagliaferri Brera-Merate Observatory, F. Favata, Space Science Department of ESA and J. Schmitt, University of Hamburg, Germany. Broad band spectral properties of Seyfert 1 galaxies observed with BeppoSAX Piro et al. 2000, Advances in Space Research, Volume 25, Issue 3-4, p. 453-457. BeppoSAX monitored the BL Lacertae object MKN 501 during a very high intensity state. These observations revealed spectacular luminosity and spectral variability (right panel) associated with simultaneous emission at extremely high energy (TeV band). MKN501 is one of only three extragalactic sources detected at TeV frequencies. Courtesy of E. Pian, TeSRE Institute, CNR, Bologna, Italy BeppoSAX broad-band X-Ray spectra of two Active Galactic Nuclei: the Quasar 3C273 and the Seyfert type 2 galaxy MKN 3. The spectral distributions are similar above approximately 10 keV (PDS data) but very different at lower energies where intervening materials in MKN 3 absorb most of the soft X-rays. Courtesy of M. Cappi, L. Bassani, TeSRE , CNR.

Strongly different spectra such as those of3C273 and MKN 3 can simply be the result of different source orientations as predicted by the "Unified Schemes of AGN". The diagram on the right side, adapted from Urry and Padovani, shows the basic assumptions of this theory. Courtesy of M. Polletta, ITESRE/CNR, Bologna, Italy Spatially resolved spectroscopy of SNR Cas A in the MECS energy band (1.5 - 10 keV)

1.67 - 2.14 keV (Si) 2.18 - 2.83 keV (S)

2.87 - 3.48 keV (Ar) 3.52 - 4.31 keV (Ca)

Si S Ar Ca Fe

5.91 - 7.26 keV (Fe) 8.00 - 10.00 keV

Courtesy of M.C. Maccarone, IFCAI/CNR, Palermo, Italy Before BeppoSAX, for about 30 years, the nature of GRBs was unknown. Are they galactic or extragalactic phenomena ? The Gamma-Ray Bursts Imaged by BeppoSAX

Follow-up X-ray observations of GRB 970228, with the BeppoSAX Narrow Field Instruments, detected an uncatalogued X-ray source 1SAX J0501.7+1146, declining in intensity (see X-ray images).

Follow-up optical observations also detected a fading optical counterpart (IAU 6584) at the 1SAX J0501.7+1146 position. This is the first confirmed optical counterpart of a gamma-ray burst. 10 May 1999 GRB990510

A new spectacular “Gamma Bang” detected by BeppoSAX 10 February 2000 GRB000210

Bursts into the new millennium: another “mini Big-Bang” caught by BeppoSAX Since launch BeppoSAX has located a number (more than 50) of Gamma-ray Bursts (GRB) with positional uncertanties of a few arcminutes.

The events were simultaneously detected in the Gamma-ray burst monitor (GRBM, 60-600 keV) and in the Wide Field Cameras (WFC) X-ray detectors (2-30 keV) from which the positions were derived. BeppoSAX and the 1998 Bruno Rossi Prize

“The 1998 Rossi Prize of the High Energy Astrophysics Division of the American Astronomical Society is awarded to the BeppoSAX Team, represented by Prof. Livio Scarsi and Dr. Jan van Paradijs for the discovery of the X-ray and optical afterglow of gamma-ray bursts, making possible the solution to the 30 year old problem of fixing the distances to the gamma-ray burst sources.” DOCTEUR HONORIS CAUSA, Universitè Paris VII, Denis Diderot. Cérémonie de remise des titres le jeudi 3 avril 2003 en Sorbonne, Paris http://www.sigu7.jussieu.fr/comm/DHC/

Eloge du Professeur Livio Scarsi, Docteur HONORIS CAUSA Coming back to Cosmic Rays ! Thanks to the opportunity offered by Prof. A. Zichichi of using detectors and electronics of a CERN experiment no more in running, Livio Scarsi together Alan Watson and Jonh Linsley implement an experiment in Averah Park (UK), PLASTEX running contemporary to the Haverah Park array. The experiment is devoted to the study of space-time structure of extensive air showers Always animated from juvenile enthusiasm, Livio Scarsi has entered in the new millennium with the proposal of a new and ambitious space mission, EUSO , Extreme Universe Space Observatory. More than one hundred researchers from several scientific institutions in six European countries, in USA and Japan have participated to this challenge. Once again, Livio Scarsi has been the leader of a big international collaboration.

EUSO, the first Space Mission devoted to the exploration of the outermost bounds of the Universe through the detection of the Extremely High Energy Cosmic Rays.

Volcano Ranch, Agasa, HiRes, but statistics from ground based experiment is not enough to clarify science: existence of GZK effect (limit of 50 Mpc), bottom-up (acceleration process , wich objects ?), or top-down origine…

In its own, EUSO represents the non conventional way to look beyond at the Extreme Universe using from Space the largest available detector for the Extraterrestrial Energetic Radiation, as represented by the Earth Atmosphere. UHECR from Space: evolution of ideas and proposals …

John Linsley, 1979 SOCRAS - Satellite Observatory of Cosmic Ray Showers

Yoshi Takahashi, 1994 MASS – Maximum-energy Air Shower Satellite

stereo Livio Scarsi, 1995 AirWatch (Europe) 1996 OWL (USA) ? mono

1997-1999 AirWatch-OWL (Europe), OWL-AirWatch (USA)

Livio Scarsi, 1999 EUSO – Extreme Universe Space Observatory (free flyer)

2000 ESA recommends EUSO on board the International Space Station ISS 2001-2004 Study and conceptual design (Phase A) of EUSO on board the ISS BUT….. November 2005 – EUSO is frozen by European Space Agency due to difficulties (Financial ESA difficulites, ISS, Shuttle, …) Livio didn’t have time to find a solution, as 18 years before when the Challenger disaster stopped the SAX program !

On march 16 , 2006 , he left us ! “Hello, guys … Enjoy your life !”

Livio has been and will be always a reference, both for the Italian and the International Scientific Community. All people knew him have had the way to appreciate his high scientific skill, his charisma, his iron will to argue for what he believed, his optimism, his deep humanity.