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Pisgah Astronomical Research InstituteRadio and Optical
Telescopes
J. D. Cline, M. W. Castelaz (PARI)
D. Moffett (Furman University)
M. Lopez-Morales
(UNC-Chapel Hill)
[#15.01] AAS 197th Meeting, January 2001
The Pisgah Astronomical Research Institute (PARI) is a not-for-profit public foundation dedicated to providing research and educational access to radio and optical astronomy for a broad cross-section of users.
PARI is located among the 160,000 Pisgah Forest acres controlled by the US Forest Service west of Asheville, North Carolina.
The PARI 200 acre site is located in an area relatively free of light and radio interference. There are over 20 buildings providing more than 100,000 square feet of temperature controlled operational space.
•PARI is a research lab open to astronomers for on-site radio observations project development instrument development postdoctoral research
•Visiting astronomers are expected to support their research conducted at PARI through university, public or private grants.
Visiting Astronomers are also encouraged to develop Educational Initiatives
K-12 teacher workshops Promote requests to develop summer
outreach programs to pre-college and pre-high school teachers
Undergraduate research Graduate research
Furthermore, PARI will provide the staff needed to assist in the visiting
astronomers initiatives opportunities for the public to participate
in general astronomy education remote access to 4.6-m radio telescope for
schools
Two 26-m Radio Telescopes
The 26-meter radio telescopes are multi-band antennae originally designed for tracking fast-moving, low Earth orbit satellites and manned spacecraft.
The 26-meter radio telescopes have been upgraded with 20-bit encoders, one of which has computer controlled motors for precision tracking of celestial targets at sidereal rates.
The 12.2-m Telescope
The 12.2 Meter radio telescope is a precision surface antenna protected by a Gore-Tex® radome. The antenna is an elevation over azimuth configuration, controlled remotely via fiber optics from the main control center in building #1. RF is also linked via fiber optics to the main control.
Prime focus feeds currently in place support 6 cm (4.6 - 5.1 GHz) and 3 cm (10.6 - 10.7 GHz) reception. A removable cassegrain subreflector and feed assembly is also available for 6, 5, and 4.5 cm (4.6-5.1, 6.0, and 6.7 GHz) operation.
The 4.6-m Telescope
TThe antenna is currently he antenna is currently configured for 21 cm (1.42 configured for 21 cm (1.42 GHz) reception. Plans are GHz) reception. Plans are to complete a program for to complete a program for remote control of the radio remote control of the radio telescope via the Internet. telescope via the Internet.
The goal is to provide The goal is to provide hands on data collection hands on data collection using remote access of the using remote access of the antenna for high school antenna for high school and college classes.and college classes.
Additional feeds for 6, 5, 4.5, and 2 cm (4.6-Additional feeds for 6, 5, 4.5, and 2 cm (4.6-5.1, 6.0, 6.7, and 12.0-15.6 GHz) are planned 5.1, 6.0, 6.7, and 12.0-15.6 GHz) are planned for this antenna.for this antenna.
The Jupiter-Solar Antenna Jupiter emits periodic energy bursts as its moon Io cuts through the magnetic fields of the planet. The energy output is equivalent to a thermal source with a temperature of ~1,000,000 K.
To study the powerful radio emission variations as a function of frequency, R. Flagg, (Univ. of Florida), and Jim Sky (Radio Sky Publishing) have designed hardware to work with a pair of M-Squared 17-30LP7 log periodic yagis to be used between 17 and 30 MHz.
Solar energy bursts are being measured during the day using this antenna facility.
Radio Observations
26-m antenna observations conducted thus far have been used to test our receivers and detectors. Below are some continuum and spectral-line observations
Single spectrometer scan centered at 1420 MHz showing spectral features from neutral hydrogen gas (HI) as observed toward the active galaxy Cygnus A.
Bandpass-corrected HI spectrometer scans.
Integrated HI spectrum toward Cygnus A. Channels have been assigned Doppler-shifted velocities with respect to the observer’s rest frame. HI emission, and absorption of radio emission from Cygnus A by a distant galactic hydrogen can be seen above.
Three-dimensional representation of the above 5-GHz image.
5-GHz false color image of the Orion Nebula formed from slew scans. Blue is lowest brightness, red is highest.
The Pisgah Survey for Detached Low-Mass Eclipsing Binaries.
Scientific MotivationRecent advances in stellar modeling of low-mass stars and Recent advances in stellar modeling of low-mass stars and brown dwarfs have not been accompanied by an attempt to brown dwarfs have not been accompanied by an attempt to obtain accurate measurements of these objects' most obtain accurate measurements of these objects' most fundamental parameters: their masses and radii.fundamental parameters: their masses and radii.
Observatory housing the 0.2-m telescope at PARI
Logarithmic representation of the mass-radius relation for stars below 1 M . The lines represent theoretical models from Baraffe & Chabrier, Tout et al.,D’Antona & Mazzitelli, Dorman et al., and Neece (see references). The points correspond to the components of CMDra, GJ2069A, and YYGem.
The observed mass-radius relation (see figure below) for The observed mass-radius relation (see figure below) for stars below 1 Mstars below 1 M has only six reliable measurements from the has only six reliable measurements from the components of the eclipsing binaries CMDra, GJ2069A and components of the eclipsing binaries CMDra, GJ2069A and YYGem. These few points are not enough to test and YYGem. These few points are not enough to test and constraint the models.constraint the models.
The solution to this problem, and the goal of this survey, is to The solution to this problem, and the goal of this survey, is to find more low-mass detached eclipsing binaries, which can be find more low-mass detached eclipsing binaries, which can be used to directly measure masses and radii. used to directly measure masses and radii.
The candidate systems will have a variation on brightness of at The candidate systems will have a variation on brightness of at least 0.2 mag, V-I least 0.2 mag, V-I 2.0, and orbital period P 2.0, and orbital period P 2 days. 2 days.
Parameters of the Survey The camera-telescope system yields a scale of 2.25” per pixel, and a total field of 1.64 sq. deg. per image (see image below).
Images are taken in the I band, reaching 15 magnitude with S/N-ratio~5 in three-minute exposures.
The camera is operated at –25°C, giving a dark count rate of less than 0.16 electrons per second.
Under good weather conditions, the survey covers 40 fields per night, centered in the equatorial plane. Ten of the fields are sampled at least 4 times per night.
Sample field centered at RA=16h30m19s, Dec=-02°41’30’. The image contains the 23.4x19.5 central arc-minutes of one of our 1.64 sq. deg. test frames. The two stars marked appear as suspected variables in the NSV Catalog. Their apparent V magnitudes are 12.1 and 14.2, respectively.
Expectations and Goals
References
Based on theoretical calculations, we expect to find one low mass detached eclipsing binary of magnitude I < 15, with orbital period 2 days in every 35-40 fields surveyed.
The survey will need two months to sample this many fields, therefore we expect to detect at least 15 binaries over the three-year lifetime of the survey.
As a by-product, we will be able to detect all the variables in the fields covered, down to our magnitude limit. This will be a contribution to variable stars databases initiated by other ongoing projects like ASAS, OGLE or ROTSE.
Adding the necessary radial velocity follow-up of the candidates discovered by our survey, the determination of their masses and radii will suppose a factor of 5 increase in the actual knowledge of the mass-radius relation of the lower main sequence.
•Baraffe, I, & Chabrier, G., 1996, ApJ, 461, L51. •D’Antona, F. & Mazzitelli, I. 1982, ApJ, 260, 722. •Delfosse, X., Forveille, T., Mayor, M., Burnet, M. & Perrier, C. 1999,A&A,341,L63. •Dorman, B., Nelson, L.A., & Chau, W.Y. 1989, ApJ, 342, 1003. •Leung, K.C. & Schneider, D. 1978, AJ, 83, 618. •Metcalfe, T.S., Mathieu, R.D., Latham, D.W. & Torres, G. 1996, ApJ, 456, 356. •Neece, G.D. 1984, ApJ, 277, 738. •Tout, C.A., Pols, O.R., Eggleton, P.P. & Han, Z. 1996,MNRAS, 281, 257.
•
•PARI has been awarded a grant from the Community Foundation of Western North Carolina to establish an Outreach Program.
• This program supports PARI’s technical staff efforts to promote education in astronomy and related sciences in the public schools of North Carolina.
• The portable planetarium provides access and a tool for learning that has not previously been available to the schools of western North Carolina.
• We anticipate that this program will be made available to more than 5,000 students per year.
K–12 OUTREACH PROGRAM
STARLAB
PORTABLE
PLANETARIUM
SGRA
The School of Galactic Radio
Astronomy
Proposed as an experience-based school room for regional use by elementary, middle, and high school teachers and their students
Reinforces student use of math, physics, chemistry,and computer science.
Relies on Internet access to PARI’s remote-controlled radio telescope.
The purpose of SGRA is to teach the basics of scientific inquiry, which includes methodology, critical thinking, and communication of results to grades 8-12.
Curriculum includes: electromagnetic radiation, chemistry, math skills such as graphing & interpretation of graphs, contour maps, and trigonometry, computer skills, and technology.
Process and evaluations of the SGRA will be instituted via online student observation logbooks and teacher feedback.
Workshop to be Hosted by PARI, August 2001
Small Radio Telescopes Small Radio Telescopes in Modern Astronomyin Modern Astronomy
PARI WILL PRESENT THE OPPORTUNITY FOR
ASTRONOMERS TO COME TOGETHER FOR THREE DAYS TO SHARE AND COLLECT IDEAS IN
RESEARCH AND EDUCATION, INSTRUMENTATION, AND
INNOVATIVE PROGRAMS FOR RADIO TELESCOPES 3 TO 26 M
Workshop Topics Include
The role of radio telescopes in surveys, long-term monitoring projects, and networks.
Using radio telescopes for astronomy and astrophysics education.
Remote, robotic, and on-site observing modes, instrumentation development, data collection and web access.
FOR MORE INFORMATION, PLEASE LEAVE YOUR NAME ON THE SHEET BELOW THIS POSTER.
CONTACT INFORMATION
Pisgah Astronomical Research Institute1 PARI DriveRosman, NC 28772-9614
WWW.PARI.EDUPhone: (828) 862-5554FAX: (828) 862-5877
For further information call or e-mail
Don Cline [email protected] future project questions
James Powers [email protected] for general and grant questions Michael Castelaz [email protected] for education/astronomy-related questionsCharles Osborne [email protected] for hardware technical questionsDavid Moffett [email protected]
for radio astronomy questions
