Lesson for my child : Curiosity

Humans are curious about variety of phenomena in our daily lives: rains, fires, hurricanes/ storms, waves, tides. It also applies to things that we can not experience using our senses: clear sky, ocean depths, stars, Sun, Moon, etc.

1. Throughout their existence humans all over the planet have asked questions about things that were around them: their surroundings, our planet, the cosmos, the origin of all the things, and where were all going to end. वेद, or the Vedas called them पंचमहाभूत, or the five elements: Earth, Water, Fire, Wind, and Sky. Everything is made of them. It is not important if Vedas were correct or not, what matters most is that, humans thought of the cosmos. The surrounding natural elements and cosmos on the larger scale made an impact on those early Hindu thinkers.
2. Those Hindu thinkers related various phenomena as manifestations of those five elements. This is characteristic of humans: we relate seemingly disparate phenomena using fewer logical elements. At one level, we should understand that those associations are not real, but they allow us to comprehend phenomena in an organized manner; and if the exercise is successful, we can predict certain things using those associations.
3. Curious human will observe and think about apparent patterns. This is most crucial for the survival of species: food resources, predicting natural phenomena (predicting tides is crucial for fisher-folk, rains are important for farming).
4. This curiosity also leads to betterment of lives:

-- waves/ tides and fishing
-- rains and paddy farming
-- diseases and micro-organisms

Here is a true story of a Goan boy who was bitten by a snake. The snake was of harmless kind, although very similar to poisonous adder snake in its appearance. A Tantrik was summoned by parents to `cure' their boy of the poison. No wonder, the boy was fine after the Tantrik performed his rituals. It so happened that the boy was bitten by a snake again, however, this time by a real poisonous adder. His parents preferred the Tantrik once more, however, all his rituals took precious time away. The boy died the next morning.

The story is important, in that one has to be curious and understand that poisonous snake alone cause harm. As far as we can make out patterns on the snake-back, we are safe, else we face grave consequences. The same goes for the rest of the nature.

Life is precious and there are no guarantees. However, curiosity and learning allow us to survive in this world better, and also make it a richer experience.

What I want my child to know

I hope to be a father soon. As a good father, I would present the best part of me to my progeny. Apart from my genes, the best thing I can pass on to my child is what I learnt in my long education in my life so far. It is the rational/ scientific thinking and attitude, along with the self-awareness, that identifies humans.

In a series of posts, I will now outline my thoughts on scientific thinking and self-awareness. One day my child would read this, learn something, and perhaps laugh.

Coherent Dedispersion

Our code to remove dispersion effects from pulsar time series is now in its 5th revision. The major changes are:

1) the code reads one period of pulsar in small chunks of 32k samples
2) the chunks are dedispersed and smoothed with a factor = 4096
3) smoothed chunks are appended to the final time series.

Going Dutch !

I have now shifted my base from BITS-Pilani, Goa Campus (in India) to ASTRON, the Netherlands. It is quite a change. This blog should reflect that change in a big way. For now, there are two things going on simultaneously: pulsars (single-pulse work and coherent dedispersion) and shell search.

You will find me blogging here extensively on these in the coming days. The personal posts are on my other blog, The Laughing Buddha.

PPV maps details

Equations for the position to velocity (PPV) cubes were computed for a 3-D cube of density with its center (point P) at a given distance (d) from Sun (S). Here, by data convention, Y axis is along the line of site (SP).

For any pixel in the cube (point Q), the line of site SQ would then subtend an angle wrt the center (SP). Let Q' be the projection of Q on X-Y plane, therefore, SQ' has projections of x & y along the two axes.

We can then relate R0 (= CS = distance of Sun from Galaxy's center), R ( = distance CQ'), distance d (SP), and distance d' (SQ') through other quantities and angles (such as longitude= angle CSP).

The projection of relative velocity between S & Q' (due to galactic rotation) is added to the projections of the pixel velocities (vxx, vyy and vzz). Doing this for each pixel creates the cube "v_los". We sort the pixel values falling in different velocity bins, and make velocity maps of width 1 km/s.

Simulations: PPV maps ready

1. Testing with 10x10x20 cubes
2. PPV maps seem to be all right.
3. Will now test on the desktop with full limits put in.
   

MHD Simulations: PPV maps

1. Read density, vxx, vyy,vzz cubes
2. Compute pixel (radial) velocities due galactic rotation
3. Add components of vxx,vyy,vzz from individual pixel values.
   
4. ERROR in writing the files in PPV files

MHD simulations

Miguel has asked for the latest in MHD simulation cubes. so, i have read data with Python, instead of C++. it is a lot faster to write the code and test it. it is also to process and update.

1. Read the density array: split the lines in parts
2. Store the data in density_data[] and reshape it.
3. plot select slices along z, and they are okay.
4. Now read density and velocities.

flucatuation analysis: easyGUI

1. The program menu now has a comprehensive logical structure. There will be text files holding menu data.
2. Program reads menu (text) files and records pulsar parameters as read from the data file. These can be later used for various analyses.
   
3. The main menu leading to average profile in a sub-menu "fold menu". There wiill be plot menu on all such sub-menus.
4. I can now display pulse sequence and zoom in on the chosen sequence area.

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fluctuation analysis: EasyGUI

EasyGUI is god-sent

1. I can display various options in a menu window and ask the user to click and choose.
2. I can choose the data file and read it.
   
3. I can plot the average profile

All this in 3 days work. Python is getting better every day.

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