The field of astronomy has the ability to keep everyone from 7 to 77 mesmerized, be it by its sheer magnitude, beauty and variety of structures, its deep mysteries or the possibilities. Before I talk of my field of work, I need to give a general introduction in the simplest way possible, and of course I assume that the reader has some basic ideas like what a light year is.
Our life is centred around the Sun. The nearest star from the Sun is slightly more than 4 light years away. Take a moment to try to comprehend the distance, and then consider that the Solar System is a part of a galaxy (Milky Way) that is 100,000 light years across. And this galaxy harbours 10^11 stars. Just like satellites orbit around planets, recent observations have yielded that there are small satellite galaxies around most major galaxies including the Milky Way galaxy. These are called Dwarf galaxies and have a very low surface brightness.
The nearest major galaxy from Milky Way is Andromeda, and on a clear night it is visible to the naked eye like a haze. It is smaller than Milky Way and it is 2.5 million light years away. And if you think that these figures are huge, learn to live with the fact that there are about 50 galaxies within the local group of galaxies, and about 100 local groups form a supercluster of galaxies. Our Milky Way is one of the 4000 odd galaxies in the Virgo Supercluster (110 million light years across). And that is nothing compared to the farthest object detected (about 13 billion light years away). One must also realize that the farther an object is, the light coming from it is farther into the past.
Now I would throw in another weird observational fact about space. It is expanding. This term can be misleading at times, and I would use a line from Wikipedia: "It is an intrinsic expansion—that is, it is defined by the relative separation of parts of the universe and not by motion "outward" into preexisting space." A clarificatory diagram on this point and for a better idea of distances: http://en.wikipedia.org/wiki/File:Embedded_LambdaCDM_geometry.png
To explain this phenomenon of expansion, Big Bang theory was developed, and the mathematics of it yielded the fact that what we see forms only 5% of the total mass-energy. That includes the massive bodies forming all the stars including black holes and the energy emitted from these mostly in the form of photons. Of the remaining 95%, the theory attributes 23% to dark matter and the rest 72% to dark energy. Frankly speaking, at the moment we know very little about dark energy. However for dark matter there is evidence, and a clear characterization of its properties. Dark matter is made of non-baryonic (don't mind the terminology) particles which don’t interact with light but have gravitational effects. Basically light passes right through it without any effect as if transparent, and the only way we know that there is something out there is from the gravitational pull of this mysterious dark matter on other visible celestial objects.
The nearest major galaxy from Milky Way is Andromeda, and on a clear night it is visible to the naked eye like a haze. It is smaller than Milky Way and it is 2.5 million light years away. And if you think that these figures are huge, learn to live with the fact that there are about 50 galaxies within the local group of galaxies, and about 100 local groups form a supercluster of galaxies. Our Milky Way is one of the 4000 odd galaxies in the Virgo Supercluster (110 million light years across). And that is nothing compared to the farthest object detected (about 13 billion light years away). One must also realize that the farther an object is, the light coming from it is farther into the past.
Now I would throw in another weird observational fact about space. It is expanding. This term can be misleading at times, and I would use a line from Wikipedia: "It is an intrinsic expansion—that is, it is defined by the relative separation of parts of the universe and not by motion "outward" into preexisting space." A clarificatory diagram on this point and for a better idea of distances: http://en.wikipedia.org/wiki/File:Embedded_LambdaCDM_geometry.png
To explain this phenomenon of expansion, Big Bang theory was developed, and the mathematics of it yielded the fact that what we see forms only 5% of the total mass-energy. That includes the massive bodies forming all the stars including black holes and the energy emitted from these mostly in the form of photons. Of the remaining 95%, the theory attributes 23% to dark matter and the rest 72% to dark energy. Frankly speaking, at the moment we know very little about dark energy. However for dark matter there is evidence, and a clear characterization of its properties. Dark matter is made of non-baryonic (don't mind the terminology) particles which don’t interact with light but have gravitational effects. Basically light passes right through it without any effect as if transparent, and the only way we know that there is something out there is from the gravitational pull of this mysterious dark matter on other visible celestial objects.
The early universe was very uniform. However the small irregularities as has been reproduced by simulations, resulted in clumping of dark matter into haloes. All present day galaxies are nested in these haloes. Observational data of the rotational velocities of galaxies (its variation with radial distance) is also suggestive of the presence of dark matter haloes around them. If there were only baryonic (normal) matter in galaxies, all matter would have lost their energy by radiation, and would have got clumped together.
According to numerical cosmological simulations that predict the evolution of the distribution of matter in the universe, there seems to be enough observed normal-sized galaxies to account for dark matter distribution, but the number of dwarf galaxies found so far is orders of magnitude lower than expected from simulation. For comparison, there were observed to be around 50 dwarf galaxies in the Local Group, and only around 20 orbiting the Milky Way, while the predicted number is of the order of 1000. This is called the Dwarf Galaxy Problem.
And this is where I come into the picture. My internship is about developing a code that can find these missing dwarf galaxies from astronomical images. I have been trying it on a few of these images (1.5 GB each) and their cutouts, and when the procedure involved and the set of parameters used produce satisfactory results, the code will be uploaded onto the cloud, that will use the processing powers of hundreds of idle computers to process the 2000 odd 1.5 GB images (cloud computing) and give us the results. Let us see if we can find any new dwarf galaxy(ies).
On a separate note, one of the softwares I have been using for the detections is called Source Extractor. It is available under the name of Sextractor, and all its commands start with the word sex followed by a space and then the rest of the parameters and commands. There is a command to set the OS type and it goes as
>>sexmachine = 'linux'
In addition to allowing physicists their daily dose of 'sex' humour, the software also helps them in detecting celestial objects.
One of the astronomical image cutouts having a major galaxy (Spindle Galaxy - NGC3115) to the top-right. There is a dwarf galaxy, possibly a satellite to NGC3115 in the left part of the image, 2/3 distance from the top (forming a haze with a bright centre). Other objects in the image are stars (the ones forming a plus sign due to the photon overflow in the pixels) and the remaining multitudes of bright smudges against the grainy background are all galaxies from other clusters, each of roughly the same size as the Milky Way, and each a home to a zillion possibilities. All this within 1/3,000,000 of the entire sky.
On a separate note, one of the softwares I have been using for the detections is called Source Extractor. It is available under the name of Sextractor, and all its commands start with the word sex followed by a space and then the rest of the parameters and commands. There is a command to set the OS type and it goes as
>>sexmachine = 'linux'
In addition to allowing physicists their daily dose of 'sex' humour, the software also helps them in detecting celestial objects.
One of the astronomical image cutouts having a major galaxy (Spindle Galaxy - NGC3115) to the top-right. There is a dwarf galaxy, possibly a satellite to NGC3115 in the left part of the image, 2/3 distance from the top (forming a haze with a bright centre). Other objects in the image are stars (the ones forming a plus sign due to the photon overflow in the pixels) and the remaining multitudes of bright smudges against the grainy background are all galaxies from other clusters, each of roughly the same size as the Milky Way, and each a home to a zillion possibilities. All this within 1/3,000,000 of the entire sky.
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