PaST: Primeval Structure Telescope

Link to PaST Web site

I. General project/facility description

1. Overview of the facility/project
   The Primeval Structure Telescope (PaST), will be used to in an attempt locate and study the era of the first luminous objects, the epoch of reionization. The first stars likely ionized the gas around them producing a pattern of ionization that reflects the large scale density structure present at the time. The PaST array will be used to sense and study this ionization, by mapping the brightness of 21-cm neutral hydrogen emission at redshifts from 6 to 25. This emission disappears on ionization, allowing the study of large scale structure and of star formation at this very early epoch. The 10,000 antenna PaST array will be used to image ionized structures by creating 1 million pixel images of the sky. The angular scales of the images to be produced span from 5 arc minutes to 10 degrees. The array is currently under construction and over 2000 antennas have been installed.
   Currently PaST is being built as an experiment rather than as a facility. However, with 30,000 square meters of collecting area and a high bandwidth correlator, it certainly might be become a facility in the future.

2. Managing institution and organization
   
   • National Astronomical Observatories, Chinese Academy of Sciences
   • Canadian Institute for Theoretical Astrophysics, and
   • Carnegie Mellon University

3. Funding source(s)
   So far 95% from NAOC, China, rest from CMU, CITA. We have a proposal under review at NSF. If fully funded, the distribution would be approx. 50% NSF, 50% Chinese.

4. Construction history and cost
   We have spent about $300,000 in 2003 and 2004. Total construction cost will be about $3,000,000. Right now we plan to have all antennas installed by end of 2005. Full correlator installed by end of 2006.

5. Operational history and cost
   
   • Site survey and on-site prototype testing completed 2003-4.
   • 25% of antennas installed 2004.

II. Technical details

1. Specifics of telescope/instrument
   30,000 m² collecting area, arrayed as 80 phased arrays of 127 log periodic antennas. Frequency range is 50-200 MHz. The system temperature is that of the sky and varies from about 2000 to 200 K across the range. The instantaneous bandwidth is 50 MHz with a frequency resolution of 4 KHz. The field of view is about 10 degrees, and angular resolution about 5 arcminutes.

2. New capabilities anticipated/planned in next 5-10 years
   Electronic beam steering, multiple beams, lower frequency operation, a high time resolution transient search back end, a pulsar back end, and a SETI back end are all under consideration. Right now we are focusing exclusively on Early Ionization.

III. User profile

1. % of "open skies" time
   None at this time. If NSF funding is approved we will release all data, and future NSF funded programs can include open time. For now our tight budget, small team and the need to focus on the systematics of the observations preclude offering open time.

2. Institutional affiliations of users
   Right now only researchers at the three founding institutions have access to PaST data.

3. Student access, involvement, usage
   We currently have no program to offer time to outside users however once the system is working well, we may reconsider this.

IV. Science Overview

1. Current forefront scientific programs
   Future facility:NA
2. Major discoveries (through 1999)
   Future facility: NA
3. Science highlights of last 5 years
   Future facility: NA
4. Main future science questions to be addressed
   Early ionization of hydrogen between redshifts of 6 and 25.
5. Synergies with other major forefront facilities
   We will produce a very deep catalog of 50-200 MHz spectra of extragalactic radio sources. This will be used in combination with data from all frequency ranges to understand Active Galactic Nuclei. Our data will be uniquely valuable in understanding self-absorbtion mechanisms.

6. Unique contributions
   LOFAR will search for Early Ionization, but not below 108 MHz (z=12), the top of the FM radio band. PaST is the only instrument with sufficient collecting area to image large scale structure, via 21 cm emission, at redshifts above 12.

V. Education/Outreach activities

1. Visitor facility
   No visitors from outside the collaboration as yet.

2. Student programs
   Assuming NSF funding, 2 CMU students will be supported. U Toronto, and NAOC Grad students are writing thesis on PaST as well. Appox. 5 theses from the current effort.

3. Other (as apply)
   

VI. Documentation/website URLs

1. URL of facility website
   http://primeval.info

2. URL of EPO website
   
3. URL(s) of any brief overviews of project/facility
   See (astro-ph/0502029)

4. URL(s) of miscellaneous documentation