2. OSETI with MAGIC IntroductionIntroduction Radio SETIRadio SETI Optical SETIOptical SETI OSETI with MAGICOSETI with MAGIC SummarySummary July 2004

3. OSETI with MAGIC14th ISCRA Course, Erice 20042Introduction Philosophically: since the time of ancient Greek civilization, some people think that Earth is not a special place: “Principle of Mediocrity”. Scientifically: recent development on Astrometry and Planetary Search: rocky habitable planets expected to be found (NEWTON/TPF). ~ 110 Jupiter-like planets discovered so far. Earth-like planets still remains undetected due to the mass sensitivity limit of the experiments. different environments can also evolve life taking profit of some different energy sources → planets evolving life much more probable. After that, to become an intelligent kind of extra-terrestrial life could be just a question of time.

4. OSETI with MAGIC14th ISCRA Course, Erice 20043Introduction The number N of intelligent communicative civilizations in our galaxy can be estimated by the known as Drake equation where R is the yearly rate at which stars form in the galaxy (1 yr -1 ) f p is the fraction of stars that possesses planets (0.5) n is the number of planets with environment suitable for life (2) f l is the fraction of planets on which life actually develops (1) f i is the fraction of these planets in which life develops intelligence (1) f c is the fraction of intelligent life forms that developes a culture capable of interstellar communication (0.1) L is the time that this culture will devote to communication (10 6 yr) Supposing optimistic parameters → high N (e.g., those in brackets lead us to N = 10 5 communicative ETC) → Fermi Paradox: “where are they?” Drake equation N = R · f p · n · f e · f i · f c · L

5. OSETI with MAGIC14th ISCRA Course, Erice 20044 Radio SETI (traditional) Cocconi & Morrison (1959) → proposition of MASERS operating at HI frequency (1.4GHz). Moderate RF/MW background & high development of radio communication Frank D. Drake (Project Ozma, 1961) → first scientific search based on the idea of C&M, searching for HI emissions SETI programs now are restricted by radio-telescopes observations. Present searches: try to enhance their signal detection → interference & instrumental background reduction. At the moment, there are no significant signal for any of the observed targets. SETI Natural diffuse background

6. OSETI with MAGIC14th ISCRA Course, Erice 20045 Optical SETI (OSETI) Based in optical LASER: LASER devices have more power than MASER. They operate in the optical range → higher bandwidth (faster transmission of information) & atmosphere transparency. Pulsed emission ~ ns → less natural background (Cherenkov flashes). → higher probability for success with more significant results.

7. OSETI with MAGIC14th ISCRA Course, Erice 20046 OSETI with MAGIC 234 m 2 mirror surface → high concentration of light. time resolution about 1 ns → expected pulses (O(1ns)) could be resolved. PMT’s able to detect pulses with few photons → weak luminosity excess could be detected from a star. MAGIC is the largest optical reflector ever built.

8. OSETI with MAGIC14th ISCRA Course, Erice 20047 OSETI with MAGIC Single Pixel Threshold ~ 8 phe Average QE ~ 20 % Transmissions ~ 80 % Mean λ for optical γ ~ 500 nm Energy/area| pulse ~ 8.1·10 -20 J/m 2 Telescope parameter (minimum value) Minimum pulse energy to get a Single Pixel Trigger γ PMT Logical pulse COUNTER Pulse rate Single pixel threshold (discriminator level) analogical pulse 1ns

9. OSETI with MAGIC14th ISCRA Course, Erice 20048 OSETI with MAGIC But LASER traveling : for reasonable parameters: d t ~ 1m D ~ 10 pc Minimum Energy Emitted per Pulse ~ 24 kJ Helios ~ 3.6 MJ per 3 ns pulse !!! A diverged beam LASER dtdt D

10. OSETI with MAGIC14th ISCRA Course, Erice 20049 OSETI with MAGIC ν LASER ≤ R spt max to be detected, and also it must be above the R spt accidental due to stars luminosity in a significant way. R spt accidental can be estimated: for an F type star (like our Sun) with a magnitude 5.5, Ғ Earth ≈ 2.52·10 -8 ·10 -0.4·m J·s -1 ·m -2 N phe/ns detected ~ 13.5 phe/ns R spt accidental ~ 15 MHz N phe/ns NSB ~ 0.13 phe/ns What can MAGIC do just now ? P >8phe/ns ~ 1.5·10 -2 ↓ Δt ~ 1ns → ↓ R spt max readable by MAGIC (expected) ~ 100 MHz R spt Cherenkov ~ 180 Hz

11. OSETI with MAGIC14th ISCRA Course, Erice 200410 OSETI with MAGIC MAGIC parameters D t =1m ↑ closest star Galactic ↑ Center ←Helios (at 100 MHz) KI→ Following Kardashev’s civilization criteria (based on the energy resources employed): KI (employing their planet) KII (employing their star) KIII (employing their whole galaxy) P used (W) R detec (pc) KI 10 11 2 KII 10 26 63·10 6 KIII 10 37 20·10 12

12. OSETI with MAGIC14th ISCRA Course, Erice 200411Summary The MAGIC Telescope is working now, and R spt data is taken. After that, to find an intelligent kind of extra-terrestrial life could be just a question of time (spent in analysis)!

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