The Milagro GammaRay Observatory By Timothy Willett CROP

The Milagro Gamma-Ray Observatory By Timothy Willett CROP: Roncalli Division

Milagro’s Etymology and Location MILAGRO stands for Multiple Institution Los Alamos Gamma Ray Observatory n The word “milagro” is also Spanish for “miracle” n The detector array is located in the Jemez mountains near Los Alamos, New Mexico n Altitude: 2, 630 m (8690 ft) above sea level n <Umdgrb. umd. edu> Milagro <http: //www. physics. nyu. edu/~am 3/images/hdrsite. jpg>

What is Milagro? n n n Milagro is a large pool of water filled with Photo Multiplier Tubes The pond is 80 m x 60 m x 8 m The pond is lined on the bottom, covered on the top, and filled with water PMTs are suspended 1. 5 and 6. 5 meters below the water surface The full detector, completed in fall of 1998, includes 723 PMTs Inside Milagro http: //www. lanl. gov/milagro/

More Inside Milagro <http: //www. physics. nyu. edu/~am 3/milagro. html>

Comparison of ACT : EASA An Air Cherenkov Telescope (ACT) is a system of mirrors that focuses Cherenkov light into PMTs to learn more about cosmic ray showers n They can only be operated at night n An Extensive Air Shower Array (EASA) is characterized by sparsely positioned detectors (typically plastic scintillators) which emit light when a cosmic ray passes through them n They can operate under all conditions, night or day n Each type of cosmic ray detection has its own advantages and disadvantages n <http: //www. lanl. gov/milagro/detecting. shtml> Left: ACT Right: EASA

Chart of Comparison n Milagro was designed to combine the low energy threshold of ACTs with the large field of view and high duty cycle of EAS arrays

Milagro’s Purpose and Goals n n n Search for gamma-ray bursts emitting Te. V gamma rays Search for nearby active galactic nuclei (AGN) Search the Northern Hemisphere sky for sources of Te. V gamma rays Search for primordial black holes (PBH) Study the properties of the solar magnetic field <http: //umdgrb. umd. edu/cosmic/milagro. html> Simulated Shower Hitting Milagro

So what makes Milagro new? This is a new type of detector: a water Cherenkov extensive air shower array n This is the first example of a large continuous pool being used as a gamma-ray telescope n Using Milagro, we can observe the Universe over 20 order of magnitude in photon energy n Milagro is the first telescope capable of continuously monitoring the Northern sky in this energy range. n <http: //www. lanl. gov/milagro/ everyone. shtml>

Milagro Benefits <http: //www. lanl. gov/milagro/concept. shtml> n The index refraction of water is much bigger than that of air n n n The number of Cherenkov photons per unit track is greater The Cherenkov light angle in water is 41°, while it is only 1° in air More Material into which the particles can bump

In-Depth: Active Galactic Nuclei are believed to be supermassive black holes surrounded by accretion disks n These “black holes” seem to emit beams of high energy particles n These beams, or jets, are spewed perpendicular to the disk n <http: //www. lanl. gov/milagro/physics. shtml>

Another look at AGN <http: //www. lanl. gov/mila gro/physics. shtml>

The Gadgets Pond, Liner, and Cover PMTs and anchor grid Cover inflation system Lightning protection system Water Purification and Circulation Apparatus n Data Acquisition and computer…stuff n Environmental monitoring system n Computer Simulation Software n n n P M T s <http: //www. physics. nyu. edu/~am 3/milagro. html>

Nowadays at Milagro n Publications in 2001 suggest activity still today n There is a collection of animations that show the research Milagro has accomplished in a few short years: http: //scipp. ucsc. edu/milagro/Animations/Pages/Mil. Anim. Index /E 200 Me. V. html http: //scipp. ucsc. edu/milagro/Animations/Pages/Mil. Anim. Index /G 2 Te. VBottom. html http: //scipp. ucsc. edu/milagro/Animations/Pages/EASIndex. Pa ges/EASIndex. G 2 Te. VPart. html

(Kinda Boring, But Important) n n n n n George Mason University Los Alamos National Laboratory New York University of California, Irvine University of California, Riverside University of California, Santa Cruz University of Maryland, College Park University of New Hampshire, Durham University of Wisconsin <http: //www. lanl. gov/milagro/collaboration. shtml>

What did I tell You? n n n n n Where the name comes from/location What Milagro is and what it does Comparison of ACTs and EASAs Milagro’s purpose and goals Why is Milagro new/what are benefits? In-Depth: Active Galactic Nuclei Gadgets they use Nowadays at Milagro (Animations) Collaborators I told you what I told you <Timothy Willett>

(Who I stole my information and cool pictures from) Bibliography http: //scipp. ucsc. edu/milagro/Animations/Anima tion. Intro. html http: //umdgrb. umd. edu/cosmic/milagro. html http: //www. lanl. gov/milagro/ http: //www. physics. nyu. edu/~am 3/milagro. html