Arecibo San Juan Mayaguez Daniel R. Altschuler NAIC-Arecibo Observatory Ponce The Arecibo Observatory is Part of NAIC which is operated by Cornell University under a cooperative agreement with the NSF Puerto Rico NATIONAL ASTRONOMY AND IONOSPHERE CENTER (NAIC) Arecibo Observatory Operated as a visitor oriented national research Facility by Cornell University under a cooperative Agreement with the National Science Foundation (NSF) FACILITIES - 305 m Radio Telescope Became operational in 1963 Reflector surface upgrade in 1974 Gregorian upgrade 1997 Optical and Lidar Laboratory RESEARCH AREAS Radio Astronomy ~75% (galactic and extra galactic spectroscopy, pulsars, VLBI) Planetary Studies ~ 10% (planetary surfaces, comets, asteroids) Space and Atmospheric Sciences ~15% (ISR, LIDAR ) OPERATION ~ 140 Permanent employees (~ 18 scientific staff) Educational Facility M31 - Andromeda Pulsars Periods from 1.57 ms to 8.5 sec Neutral Hydrogen in galaxies 1420 MHz / 21 cm Other spectral features from interstellar molecules 1
Incoherent Scatter Radar (430 MHz) Centaurus A NGC5128 Radio continuum Solar Minimum Altitude km Solar Maximun Hours Proceedings of IRE Nov 1958 A parabolic reflector was initially considered but later in order to be able to reach a large area of the sky it was decided to build a sphere 1959 Why this hole in Puerto Rico? Karst formation offers convenient holes Need proximity to equator to observe planets November 1959 Contract signed between Cornell and AFCRL/ARPA 1962 2
October 29, 1962 March 4 1963 Azimuth lift surface June 1963 June 1963 reflector August 14, 1963 The original line feed was 96 feet (29 meters) long. It was built of aluminum and had a weight of about 10,000 pounds. Operated at a frequency of 430 MHz. (Now at Learning Center) Telescope Optics I Line feeds 3
April 7, 1964 First radar echo form Mercury 1964 Nature 1965 FIRST ARECIBO UPGRADE 1972-1974 1 - NEW SURFACE (RMS < 3mm) HIGH FREQUENCY OPERATION (SPECTRAL LINE OF NEUTRAL HYDROGEN AT 1420.405 MHz) 2 - NEW 2380 MHz RADAR (S-BAND). JULY 1974 - PSR 1913+16 FIRST DETECTED (Joseph Taylor and Russell Hulse) First Upgrade New surface Last Panel # 38,778 - November 1973 Discovered in 1974 at Arecibo it consists of a binary neutron star system one of which pulsates towards the Earth. The reducing orbital period represents a loss of energy, which can only be accounted for by gravitational radiation. 4
Nature 19 The orbit of the pulsar appears to rotate with time; in the diagram, notice that the orbit is not a closed ellipse, but a continuous elliptical arc whose point of closest approach (periastron) rotates with each orbit. The rotation of the pulsar's periastron is analogous to the advance of the perihelion of Mercury in its orbit. The observed advance for PSR 1913+16 is about 4.2 degrees per year. The pulsar's periastron advances in a single day by the same amount as Mercury's perihelion advances in a century. 700,000km 7.75 h 35,000 x Mercury Hulse - Taylor Nobel Prize 1993 GREGORIAN UPGRADE 1993 1997 1 Ground Screen to reduce spillover noise focus 2 New drive systems including active tie-downs 3 Replace line feeds with a reflector feed system Gregorian Optics 4 New receivers 5 New S-band transmitter with twice the power 6 Improve surface accuracy of reflector to reach 10 GHz 5
May 16 1996 New Transmitter in Gregorian Gregorian receivers Horns 6
secondary horns tertiary Radio pulses from a neutron star at a distance of 2000 light years in the Virgo constellation (the pulsar PSR 1257+12) provided the first evidence for an extra-solar planetary system. Alexander Wolszczan discovered these planets in 1991 using the Arecibo radio telescope Two planets (B y C) have masses similar to Earth, and the third one (A) is like the Moon. Planet D Planets orbiting Pulsar 1257+12 stamp Radar image of Venus using Arecibo and GBT D. Campbell, L. Carter et al. 7
Venus at 2 km resolution Arecibo radar image 1999 jm8 NEO 1999 JM 8 distance 9 million km size 3 km resolution 15 meter Ice on the north pole of Mercury The brighter colors show areas that reflect radar microwaves best. These regions caused great excitement when they were discovered. Astronomers believe that the shiny circles near Mercury's Poles are patches of ice in the bottoms of craters never reached by sunlight. 400x400 km; 1.5 km resolution ALFA, operating between 1225-1525 MHz, will consist of a cluster of seven dualpolarization feeds and cooled receivers, a fiber-optical transmission system, and digital back-end signal processors. The system will enable deep surveys of, among others, new pulsars, HI in the Milky Way Galaxy and HI in external galaxies. Front end built by CSRIO Australia Telescope National Facilty 8
PULSAR SURVEYS ALFA will discover 1000 new pulsars Understand populations seen in radio and gamma ray bands Test notion that some pulsars are strange (quark) stars Exotic binaries Pulsar-pulsar Pulsar-black hole Test theories of binary evolution Test fundamental physics Survey simulations by J. Cordes, D. Chernoff, and Z. Arzoumanian Large scale structure Searches for galaxies in the ZOA HI SEARCHES Searches for underluminous objects OH megamasers 0.09 < z < 0.35 9
understanding OPUS Angel Ramos Foundation Visitor Center 1977 125,000 visitors year Independently funded Conference Center 2001 FACILITIES Exhibit Program Who knows A Day in the life of the Arecibo Observatory A Scale Model of the Solar System If we keep it up we might get rid of this pollution in the future More than Meets the Eye 10