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Pulsar Voices

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Version 2 2016-04-26, 05:40
Version 1 2016-03-16, 06:06
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posted on 2016-04-26, 05:40 authored by Richard FerrersRichard Ferrers, Anderson Murray, Ben Raymond, Gary RubenGary Ruben, CHRISTOPHER RUSSELL, Sarath Tomy, Michael Walker

The data is sourced from CSIRO Parkes ATNF.

eg http://www.atnf.csiro.au/research/pulsar/psrcat/

Feel the pulse of the universe

We're taking signal data from astronomical "pulsar" sources and creating a way to listen to their signals audibly.

Pulsar data is available from ATNF at CSIRO.au. Our team at #SciHackMelb has been working on a #datavis to give researchers and others a novel way to explore the Pulsar corpus, especially through the sound of the frequencies at which the Pulsars emit pulses.

Link to project page at #SciHackMelb - http://www.the-hackfest.com/events/melbourne-science-hackfest/projects/pulsar-voices/

The files attached here include: source data, project presentation, data as used in website final_pulsar.sql, and other methodology documentation. Importantly, see the Github link which contains data manipulation code, html code to present the data, and render audibly, iPython Notebook to process single pulsar data into an audible waveform file. Together all these resources are the Pulsar Voices activity and resulting data.

Source Data;

* RA - east/west coordinates (0 - 24 hrs, roughly equates to longitude) [theta; transforms RA to 0 - 360*]
* Dec - north/south coordinates (-90, +90 roughly equates to latitude i.e. 90 is above north pole, and -90 south pole)
* P0 - the time in seconds that a pulsar repeats its signal
* f - 1/P0 which ranges from 700 cycles per sec, to some which pulses which occur every few seconds
* kps - distance from Earth in kilo-parsecs. 1 kps = 3,000 light years. The furthest data is 30 kps. The galactic centre is about 25,000 light years away i.e. about 8kps.

psrcatShort.csv = 2,295 Pulsars all known pulsars with above fields; RA, Dec, Theta

psrcatMedium.csv - add P0 and kps, only 1428 lines - i.e. not available for all 2,295 datapoint

psrcatSparse.csv - add P0 and kps, banks if n/a, 2,295 lines

short.txt - important pulsars with high levels of observation (** even more closely examined)

pulsar.R - code contributed by Ben Raymond to visualise Pulsar frequency, period in histogram

pulsarVoices_authors.JPG - added photo of authors from SciHackMelb

Added to the raw data:

- Coordinates to map RA, Dec to screen width(y)/height(x)

y = RA[Theta]*width/360; x = (Dec + 90)*height/180

- audible frequency converted from Pulsar frequency (1/P0)

Formula for 1/P0(x) -> Hz(y) => y = 10 ^ (0.5 log(x) + 2.8)

Explanation in text file; Convert1/P0toHz.txt

Tone generator from: http://www.softsynth.com/webaudio/tone.php

- detailed waveform file audible converted from Pulsar signal data, and waveform image (and python notebook to generate; available):

The project source is hosted on github at:

https://github.com/gazzar/pulsarvoices

An IPython/Jupyter notebook contains code and a rough description of the method used to process a psrfits .sf file
downloaded via the CSIRO Data Access Portal at http://doi.org/10.4225/08/55940087706E1
The notebook contains experimental code to read one of these .sf files and access the contained spectrogram data, processing it to generate an audible signal.
It also reads the .txt files containing columnar pulse phase data (which is also contained in the .sf files) and processes these by frequency modulating the signal with an audible carrier.
This is the method used to generate the .wav and .png files used in the web interface.
  • https://github.com/gazzar/pulsarvoices/blob/master/ipynb/hackfest1.ipynb 
A standalone python script that does the .txt to .png and .wav signal processing was used to process 15 more pulsar data examples. These can be reproduced by running the script.
  • https://github.com/gazzar/pulsarvoices/blob/master/data/pulsarvoices.py

Processed file at: https://github.com/gazzar/pulsarvoices/tree/master/web

https://github.com/gazzar/pulsarvoices/blob/master/web/J0437-4715.png

J0437-4715.wav | J0437-4715.png

)

#Datavis online at: http://checkonline.com.au/tooltip.php. Code at Github linked above. See especially:

https://github.com/gazzar/pulsarvoices/blob/master/web/index.php

particularly, lines 314 - 328 (or search: "SELECT * FROM final_pulsar";) which loads pulsar data from DB and push to screen with Hz on mouseover.

Pulsar Voices webpage Functions:
1.There is sound when you run the mouse across the Pulsars. We plot all known pulsars (N=2,295), and play a tone for pulsars we had data on frequency i.e. about 75%.
2. In the bottom left corner a more detailed Pulsar sound, and wave image pops up when you click the star icon. Two of the team worked exclusively on turning a single pulsars waveform into an audible wav file. They created 16 of these files, and a workflow, but the team only had time to load one waveform. With more time, it would be great to load these files.
3. If you leave the mouse over a Pulsar, a little data description pops up, with location (RA, Dec), distance (kilo parsecs; 1 = 3,000 light years), and frequency of rotation (and Hz converted to human hearing).
4.If you click on a Pulsar, other pulsars with similar frequency are highlighted in white. With more time I was interested to see if there are harmonics between pulsars. i.e. related frequencies.

The Team

Michael Walker is:  orcid.org/0000-0003-3086-6094 ; Biosciences PhD student, Unimelb, Melbourne.

Richard Ferrers is: orcid.org/0000-0002-2923-9889 ; ANDS Research Data Analyst, Innovation/Value Researcher, Melbourne.

Sarath Tomy is:  http://orcid.org/0000-0003-4301-0690 ; La Trobe PhD Comp Sci, Melbourne.

Gary Ruben is: http://orcid.org/0000-0002-6591-1820 ; CSIRO Postdoc at Australian Synchrotron, Melbourne.

Christopher Russell is: Data Manager, CSIRO, Sydney.

https://wiki.csiro.au/display/ASC/Chris+Russell

Anderson Murray is:  orcid.org/0000-0001-6986-9140; Physics Honours, Monash, Melbourne.

Contact: richard.ferrers@ands.org.au for more information.


What is still left to do?

* load data, description, images fileset to figshare :: DOI ; DONE except DOI
* add overview images as option eg frequency bi-modal histogram
* colour code pulsars by distance; DONE
* add pulsar detail sound to Top three Observants; 16 pulsars processed but not loaded
* add tones to pulsars to indicate f; DONE
* add tooltips to show location, distance, frequency, name; DONE
* add title and description; DONE
* project data onto a planetarium dome with interaction to play pulsar frequencies.DONE see youtube video at https://youtu.be/F119gqOKJ1U
* zoom into parts of sky to get separation between close data points - see youtube; function in Google Earth #datavis of dataset. Link at youtube.

* set upper and lower tone boundaries, so tones aren't annoying

* colour code pulsars by frequency bins e.g. >100 Hz, 10 - 100, 1 - 10, <1 Hz

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