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Showing posts from July, 2013

Week 8 - Quasars & Future work

Well, i'm back in chennai again, back at IIT Madras and back to, let's say, a *normal* college life. But I'm still interested in following what i started last summer.

As you can see from my report here, and the blogposts from my previousweeks - I've mostly reproduced results from the first paper on my list - Richards et al. (2001). The next papers on the list are on Photometric Redshifts of Quasars by Richards et al (2001), Composite Quasar Spectrum from the SDSS by Vanden Berk et al (2001) and Simulated colors of objects in the SDSS color space by Fan et al (1999).
All three of these papers feed off one another and complement each other! 
A composite quasar spectrum i used to simulate the colors of a quasar at various redshifts - inorder to do this we need the band structures of the 5 bands - u, g, r, i, z of the SDSS. These can be obtained here. The loop side though is that this data is from 2001 and i haven't been able to find a more recent data pertaining to t…

Week 5

Sorry for the late update but I've been swamped. Literally swamped with data! Never have i worked on a data set that is 30GB in size, so do accept my apology. Nonetheless, here's what happened in Week 5!

So, getting to the end of my work at IIST - i'd worked on the colors of quasars and reproducing the results of a 2001 paper on the same! And the last week at IIST was just to wrap things up and finish the reports! But as you can see from my previous post here, i'd stumbled upon a peculiar (in my opinion) set of quasars! So, i was very interested in understanding them.

Hereis my report on the colors of quasars. I'm now tired of making corrections to it and adding more things to it! There will always be something interesting to add or ways to make it easier to understand but i only have so much time! So, yesterday was that day - my final edits to the report!

I've also shared a more detailed post on how i acquired the data and analyzed it here. This was one other …

Colors of Quasars- Data Acquisition and Analysis

Over the course of my project, i've had to work with multiple data sets. Two of the important data sets were the original data set used by Richards et al in their paper and a new data set that i acquired - data set whose samples are constrained by the same conditions as mentioned in the richards et al paper.
Part of the original data used in the paper can be acquired from browsed from the vizier archived data, SIMBAD object list and NED object list. These data sets can be found through a simple search for the paper on SAO/NASA ADS.
As mentioned, this is just a part of the original data set i.e data pertaining to only 898 of the 2625 quasars used in the original paper are available for download through these links. The location for the rest of the sample set is still elusive - maybe they were released as part of the SDSS Data Release 1 which is why they weren't specifically included in this data set. This conclusion is based on the fact that none of these 898 objects are c…