NASA GSFC WFF PSL CSBF GammaRay Astronomy From

NASA GSFC WFF PSL CSBF Gamma-Ray Astronomy From Balloons Jack Tueller Balloon Project Scientist SWRI Balloon Workshop Jack Tueller 1

NASA GSFC WFF Gamma Rays PSL CSBF • Gamma rays are the highest energy photons. • Gamma rays do not penetrate to the ground. • Balloons can provide access to all energies >20 ke. V (Hard X-rays and Gamma Rays) SWRI Balloon Workshop Jack Tueller 2

NASA GSFC WFF What makes suborbital different? PSL CSBF Different Risk Management Strategy • the payload is recovered • re-flights are inexpensive (<$1 M for a balloon vs >$100 M for a rocket) Higher Risk is the Best Strategy • lower cost • faster migration of new technology • smaller more focused efforts • training new workforce SWRI Balloon Workshop Jack Tueller 3

NASA GSFC WFF Gamma-Ray Astronomy from Balloons Boggs NCT GRIS Proto. EXIST In. FOCu. S HEFT GLAST PSL CSBF • atmospheric cutoff is 20 ke. V no soft x-rays • To get a high sensitivity gamma-ray payloads must be big and heavy • gamma-ray payloads work best at low latitudes magnetic shielding low background • gamma-ray payloads must be pointed • real science is possible but we need LDB at low latitudes SWRI Balloon Workshop Jack Tueller 4

NASA GSFC WFF SN 1987 A • first nearby supernova in 400 years • every instrument possible was used • many new phenomena were discovered after • balloons can provide quick access to space for timely measurements SWRI Balloon Workshop Jack Tueller PSL CSBF before HST rings 5

NASA GSFC WFF High Resolution Spectroscopy • In 1987 there were no high resolution germanium spectrometers in space like INTEGRAL • Gamma-ray lines yield nuclear yields and velocity distribution that cannot be determined at other wavelengths • Balloon experiments filled the gap GRIS, HEXAGONE, Lockheed Martin • balloon's success leads to INTEGRAL PSL CSBF GRIS SWRI Balloon Workshop Jack Tueller INTEGRAL 6

NASA GSFC WFF SN 1987 A Lines PSL CSBF • Gamma ray line profiles are not distorted by complicated effects such as resonant scattering. • Line profiles did not fit the standard models. Lines are red-shifted not blue-shifted. • But, they validate the detailed IR line profiles. • SN 1987 a was an asymmetric explosion! • future: 44 Ti lines? SWRI Balloon Workshop Jack Tueller 7

NASA GSFC WFF Nuclear Lines PSL CSBF Boggs ACT Concept Study • Nuclear lines are the unique signal of the production of new elements SWRI Balloon Workshop Jack Tueller 8

NASA GSFC WFF Type Ia Supernovae PSL CSBF Explosion is driven by radioactive decay. Much Cosmology rests on using Type Ia's as a standard candle but the physics are not understood! Boggs ACT study SWRI Balloon Workshop Jack Tueller 9

NASA GSFC WFF Compton Scattering PSL CSBF • GRIS worked with large detectors to capture all the energy and a thick collimator (800 lbs of Na. I) to isolate the source. • Compton scattering is the dominant cross section between 200 ke. V and 2 Me. V where most of the interesting gamma ray lines occur. • Localizing all the interactions allows accurate reconstruction of the source positions and spectra over a wide field SWRI Balloon Workshop Jack Tueller 10

NASA GSFC WFF Compton Telescopes Development of an Advanced Compton Telescope • several technologies are possible – – – Si & Ge strip detectors Si & Cd. Zn. Te strip detectors thick Si Liquid Xe Gaseous Xe-La. Br 3 PSL CSBF Boggs NCT ACT Concept • All are now or are proposed balloon payloads SWRI Balloon Workshop Jack Tueller 11

NASA GSFC WFF High Energy Gamma Rays • Technology for EGRET developed on HEBE balloon experiment • Go-no go test of GLAST technology on balloons Would the background rejection work? PSL CSBF EGRET All-Sky >100 Me. V CGRO/EGRET balloon test bed detector GLAST SWRI Balloon Workshop Jack Tueller 12

NASA GSFC WFF Understanding Supermassive Black Holes • How do black holes form and grow? • What stops the growth? • How do black holes effect galaxy formation? • Only in hard x-ray can you find all the sources and measure their luminosity. SWRI Balloon Workshop Jack Tueller unabsorbed (49) XMM PSL CSBF absorbed (52) BAT 13

NASA GSFC WFF PSL CSBF Proto. EXIST Swift/BAT Hard X-ray Survey >14 ke. V EXIST • A hard X-ray all-sky monitor can make great advances in variability studies of black holes. • A sensitive hard X-ray allsky survey is the only way to find all the obscured sources. SWRI Balloon Workshop Jack Tueller 14

NASA GSFC WFF Hard X-ray Focusing Optics • multilayer grazing incidence focusing optics • long focal lengths are required (In. FOCu. S is 8 m) • Cd. Zn. Te focal plane is the other critical technology. (A Si focal plane would be 1 cm thick. ) • Balloons can accommodate long focal lengths without costly mechanisms. PSL CSBF Launch Sep 16, 2004 Ft. Sumner NM SWRI Balloon Workshop Jack Tueller 9 m In. FOCu. S No mechanism was required to launch 9 m truss. 15

NASA GSFC WFF 3 Balloon Instruments Three instruments are currently active: • HEFT-CIT Columbia • In. FOCu. S-GSFC Nagoya • HERO-MSFC Each of these instruments test alternative technology for hard x-ray focusing optics. Proposed for Con-X enhancement and SMEXNu. STAR PSL CSBF HEFT In. FOCu. S SWRI Balloon Workshop Jack Tueller HERO 16

• • • NASA GSFC WFF The Black Hole at the Galactic Center PSL CSBF A supermassive black hole lurks at the Galactic Center. Like most black holes at the center of galaxies it is a very weak source at all wavelengths. What is the accretion rate and why is it so low? The GC is a very crowded area. INTEGRAL Only high resolution hard INTEGRAL imaging with >10 arcmin X-ray imaging can answer resolution is hopelessly confused. Soft this question. X-ray imaging with Chandra sees 2000 sources <10 arcmin from the center. SWRI Balloon Workshop Jack Tueller 17

NASA GSFC WFF What is the future? PSL CSBF How do we maintain strong balloon science in this field? • long duration flights at low latitude – super pressure balloon – trajectory modification system – long duration requires higher reliability - more cost and oversight • advanced designs: bigger and heavier payloads • secure and adequate funding SWRI Balloon Workshop Jack Tueller 18

NASA GSFC WFF Workforce Replenishment PSL CSBF How are future instrument builders recruited and trained? BALLOONS! Fishman BATSE • fast enough for grad student Fichtel EGRET to complete all phases of a INTEGRAL project Teegarden SPI • small enough for the Matteson university researcher Jacobson HEAO-3 • open to hands-on student participation Peterson HEAO-1 • pushing newest technology • produces significant science results 19 SWRI Balloon Workshop Jack Tueller Mission/ Instrument CGRO PI

NASA GSFC WFF Conclusions PSL CSBF • Gamma-ray astronomy could have a bright future in ballooning. • Significant science can be achieved on balloons. • Balloons are crucial to the development of new missions. • Low cost ballooning can keep a field alive in hard times. • Ballooning is the natural way to recruit and train a workforce. NASA and gamma-ray astronomy need a vigorous balloon program SWRI Balloon Workshop Jack Tueller 20