Pulsar Observations - Jean-Jacques Maintoux (F1EHN)

NOTE: All the information and images presented here are reproduced with permission.

Jean-Jacques Maintoux (F1EHN)  has detected four pulsars - B0329+54, B0950+08, B1133+16 and B2020+28 - all at 1427  MHz.

Background

Jean-Jacques has a 3.3 metre dish situated near Orsay, France.  He has conducted observations of B0329+54, B0950+08, B1133+16 and B2020+28 at this location on 1427 MHz.

This page is just a summary of Jean-Jacques extensive radio astronomy activities.  Further details can be found on his personal website.  It is mostly in French, but some information is in English.  For example, there is a detailed summary of Jean-Jacques's pulsar activities in English.

Receiving System


System Block Diagram

Dish 3.3 metre , solid reflector - AZ/EL mount
Observation bandwidth : 50 MHz
Square law detector and 16-bits ADC
Data analysis software by F1EHN

Antenna

The 3.3 metre solid dish antenna used by F1EHN to observe pulsars at 21 cm.

 
The 3.3 m Solid Dish Used by F1EHN

B0329+54 Results (April 2016)

The results of detection of B0329+54 (~ 3300 ly) as given by F1EHN.

First Attempt

Here it is seen the period is not quite right and so the phase of the pulse drifts during the observation.  Integrating down the waterfall would see the pulse be lost as they wouldn't line up in time.


Waterfall Display Showing Incorrect Period

Second Attempt

Here can be seen that the correct topocentric period has been used resulting in a straight vertical line down the waterfall.   Pulses can then by integrated as they are synchronised to the correct period.


Waterfall Display Showing Correct Period

Note the large degree of scintillation in both waterfall display graphics.   This can be a large S/N advantage if data from an 'upswing' is kept while data captured during a 'downswing' is discarded.

Folding Profiles

The graphic below shows a folding period of 3 times the pulsar period resulting in the display of three integrated pulses.


Three Integrated Pulses

This graphic shows the result of using a folding period equal to the period of the pulsar.   The extra S/N gained reveals the pre and post-pulse characteristics of B0329+54.


Single Integrated Pulse Showing Characteristic Pre- and Post-Pulses

The horizontal full-scale in the above graphic is equal to the 714 ms period of B0329+54.

B0950+08 Results (July 2016)

Using 50 bins/period, this pulse shape corresponding to a period of 253.07371ms was obtained (after tuning for a maximum SNR). The initial period was determined with the help of Wolfgang Herrmann (Astropeiler) from a TEMPO prediction. There is a little difference between the TEMPO value and the value used to find a detection.

Further analysis, using a resolution of 500 bins/period, and low pass filtering, revealed a few more details, such as the “shoulder” in the left front of the pulse, as shown below.

Another fine effort and result from Jean-Jacques.

B1133+16 Results (August 2016)

The mean flux density of this pulsar @ 1400 MHz is 32 mJy and presents a challenge for an antenna of this size.  The half-power pulse width W50 = 31.7 ms and rotation period P0 = 1.187913 sec.  The pulsar is also subject to significant scintillation.

This figure shows the scintillation effect where over 60% of the time at the start of recording the pulsar is undetectable.

The figure below shows the period of the pulsar folded over the entire recording with a resolution of 150 bins/period (the period is longer than the previous pulsars and so more samples are needed to maintain proper temporal resolution).

The signal to noise ratio is low and the limit of the current system is reached.

A final measure of this pulsar views the period of 2 consecutive folded pulses. Of course the signal to noise ratio is low, but the period is clearly observed.

B2020+28 Results (March 2017)

The mean flux density of this pulsar @ 1400 MHz is 36 mJy, the half-power pulse width W50 = 12 ms and rotation period P0 = 0.343402 sec.  The pulsar is also subject to scintillation.

This figure shows the scintillation effect where over 30 minutes of the time at the end of recording the pulsar is undetectable.

The figure below shows the profile of the pulsar.

A further verification of this pulsar views the period of 2 consecutive folded pulses at 64 bins/period. The period is clearly observed.

All in all a really nice set of results for a 3.3 m diameter dish !!!

This will inspire and encourage others to attempt the difficult task of pulsar detection with a small dish.

For more detail, refer to this summary of Jean-Jacques's pulsar activities on his website (in English).