We’ve upgraded the back-end of the 21cm spectrometer, including both DSP software and the matching SDR hardware.
The SDR receivers are now synchronized to a GPS-derived 10MHz reference clock, which provides an uncertainty in doppler measurements of approximately 30cm/sec.
The FFT resolution has been improved, by covering only the +/- 200km/sec of doppler velocity that is “visible” within the galaxy. This provides a resolution in the FFT of approximately 0.26km/sec or approximately 0.1% of the peak velocity that we are able to observe within the galaxy.
Further DSP work will allow us to double the resolution (half the doppler velocity) in the coming weeks. Stay tuned for updates.
CCERA and the Physics department at Carleton University have begun a collaborative effort in support of their undergraduate astrophysics program.
In this program, 3rd-year astrophysics students will gain remote access to CCERA’s instrumentation and data-feeds in support of a lab-based radio astronomy segment in the 3rd-year astrophysics program.
The program is coordinated for Carleton University by Etienne Rollin and Penka Matanska, both instructors in the physics department at Carleton.
The first of two 1.2m dishes for rapid surveys of the 21cm line has been brought on-line, and is currently observing at the declination of the galactic center (declination of -29 degrees).
The second dish will be brought on-line soon, which will allow spectral surveys do be completed at twice the rate of a single dish of the same size.
Stay “tuned” for more announcements….
We’ve been waiting patiently for Cassiopeia A to move far enough away from the Sun (back towards nighttime) to make observations feasible. In the last few days, we’ve been able to capture very high-quality transits, as shown below.
John Blais, of Almonte, Ontario, very kindly donated a 12ft Andrew solid-aluminum dish to us. The long-term plan is to incorporate it into our pulsar work.
Here it is in the truck, ready to go off to the lab:
We’ll make up a very-simple fixed-pointing mount, which will have the dish pointed nearly-vertical, with a 9 degree tilt to the North.
We changed the declination of the interferometer antennae to point at +41, and got several good transits of Cygnus A (3C405), shown below.
Our next target is Hercules A (3C348), at a declination of +5, currently transiting in the middle of the night for us, so no Sun problems.
Using CCERA’s “insanely small array” radio telescope, we have successfully completed a 4-day “study” of the extragalactic radio source Virgo A. Show below are both the complex-correlator outputs, and the brightness derivation. Virgo A, also known as M87, is a massive galaxy some 54 million light-years from earth. It plays host to a super-massive black hole at the center, which produces a super-luminal (apparently-faster-than-light) gas “jet” of ejected material.
Its radio flux at 611MHz (our observing frequency) is approximately 500 Jansky, or 5×10^-24 Watts/M^2/Hz of bandwidth. Since our antenna are roughly 1 M^2 in area, That means that we’re intercepting a few pico-watts of power from this source!
Our lab/office has successful moved downstairs, to Suite 104. We’re still working on bringing back some data services, like the 21cm spectrometer feed.
IN the last week, we’ve had success in making our UHF “pathfinder” interferometer operational, at a frequency of 611MHz, with a baseline of 33.5m. A “first light” interferogram from Virgo A is shown below. Virgo A, also known as M87, is a super massive elliptical galaxy roughly 54M light-years from earth. It is very luminous, making it easy to “see” with CCERA’s modest instrumentation.
We’re nearing completion of the move of our office/lab space one floor down, from suite 204 to suite 104. This was necessitated by some “reconfiguration” required by our landlord.
One side effect of this move is that we’ll not be providing the 21cm data products for a few days as we rebuild our IT environment.
The move *may* also have the desirable side-effect of reducing self-interference from our computers, since we’ll be both further away from the antenna, and also have another layer of *thick* concrete and terra-cotta block floor between our lab and the antennae on the roof.
We’ve re-jigged the pulsar array again, changing it from a 3 x 3 array to a 2 x 4 array. This geometry is much easier to manage, and it has allowed us to build a better reflector screen under the array, hopefully reducing the amount of ground radiation “seen” by the array elements.