Rahul gives unsolicited advice

I wouldn't be where I am today if not for Astronomy and Astrophysics. I failed my Computer Science 101 course in my first year of college because I could not comprehend how the variables, conditionals and loops could ever help me with my Physics degree. I stayed as far away from programming as possible until the summer of my fourth year. I had an internship where I was tasked with processing astronomical data. The professor I was working with that summer told me that I could use any programming language I wanted to process the data and for reasons that I don't remember now, I chose Python. And I absolutely fell in love. Not with the programming language itself but with the fact that I now had access to a tool that helped me with Astronomy and Astrophysics. I graduated and I got a job as a Scientific Software Developer, not too far away from Science but far enough that I don't get to work directly on anything even remotely related to Astronomy and Astrophysics. I've foll...

I got lucky in March 2022. I happened to be in Bhopal for two weeks. Specifically, I was at the Indian Institute of Science Education and Research (IISER) Bhopal with my wife. She was wrapping up some work at the TrEE lab in the Biology department. She successfully defended her PhD thesis in 2021 but she needed to go back to wrap up some loose ends. I went along with her and I got to meet her labmates. That's how I came across Improbable destinies by Jonathan Losos . As far as I can remember, it's the first biology/ecology book that I have read. It's technically a popular science book but it's not something that a school student can read and understand. But, it's damn good. I would definitely recommend it to biology and science undergraduates who are yet to understand and decide where their interests lie in. Preeti likes the fact that I can atleast know of and can use some of the vocabulary she works with on a day-to-day basis. The book introduces the reader to con...

What is the best location to place a telescope? The first answer that comes to people's minds is a mountain top. Ask them why and they might not know but they just might know that most telescopes are on mountain tops, so there must be a good reason there. Well, in fact there is a reason. Telescopes work better when placed on mountain tops because there's less atmosphere for the telescope to look through, less atmosphere that can smear the images being taken leading to better science. Actually. There's a small correction. Optical and sub-mm telescopes are best placed on mountain tops. Radio telescopes on the other hand can work just as well when placed at sea level. Now. Following up to the first question, What is the best location to place a radio telescope? Because altitude doesn't matter, the main problem is radio interference. Man-made radio interference is the biggest source of noise to radio telescopes. This is the reason why the JVLA in NA is a designa...

These Astronomical Glass Plates Made History  : For those of you who are old enough, you will remember that before there were digital cameras, photos were recorded on films and there was a studio where the films had to be taken to have them developed into pictures. Before CCDs (the chips inside digital cameras that made the films obsolete) revolutionised astronomy, astronomers used to use films, rather plates, to record images of astronomical objects and their spectra. This is an account of such plates that made history, that record some of the biggest and paradigm-shifting discoveries in astronomy. The fall… and rise and rise and rise of chat networks  : The first chat network that I ever used was google chat, which is now google hangout, and yahoo messenger. I don't know why but I wasn't into MSN Messenger. But there was a time before mine when chat networks were smaller, less technologically advanced and more geeky, so to say. This is a brilliant account of how chat net...

Instead of embedding the plotly maps into blogger posts, which BTW don't follow the blog layout, i thought it'd be better if I have a stand-alone place where only the maps are displayed! With a bit of text of course. And I've always wanted to use GitHub pages for something. So, I created a GitHub repository and page called uniLocs  where I'll keep the maps from now on. NOTE : The two previous blogposts can be found here and here .

In my previous blogpost , I talked about why I wanted to make an interactive map showing the locations of universities/labs where astronomical research is pursued. After my first attempt at plotting about a hundred locations on  a map, here are about 200 locations, spread more widely than locations just in the USA. I still haven't done all that I wanted to. And I remembered that I also wanted to add information on the application deadlines for PhD admissions at the places. Again, if you have any comments or suggestions, regarding what I already made or how I can improve it, I would love to hear them. Also, the data is available on plotly here and on google docs here 

Till November 2015, I was searching for PhD and research assistant positions in astronomy departments and labs around the world. There's no one place which lists out ALL of the places and the few lists I did found were outdated and were a list. A map is the best way to represent such a data set, in my opinion, so that is what I set out to do. I've been searching for and bookmarking universities/departments/labs/centers where people do astronomy for over 3 years now so I have a pretty long list to go through. I first had plans to automate the process of retrieving (Lat, Long) information given a URL but I couldn't figure out how to. I remember finding a website which, given a URL, would tell me the location as to where it is hosted, but I have since lost track of it. And instead of putting it off in want of a programmatic way of making this map, I thought I'll put in the time and do the whole thing manually i.e make a list of websites, check every website for a cont...

Galaxy evolution is a tug of war between the nature of the galaxy (morphology, mass, etc) and nurturing environment of the galaxy (major or minor mergers, ram stripping, etc) and to understand it, we need to understand when nature rules over nurture or otherwise. An interesting way to resolve this question is to study isolated galaxies - isolated in the sense that there are hardly any galaxies in their vicinity. The qualitative 'hardly any' was quantified to create the Catalog of Isolated Galaxies (in 1973) and then revised by the AMIGA people for a more up-to-date study. Understanding the evolution of isolated galaxies inherently tells us more about the role that the nature of the galaxy plays in it's evolution. Today, I was reading up on some interesting papers by the AMIGA people, all three on the HI (neutral Hydrogen) profiles of select isolated galaxies. The three papers can be found here , here and here . I came across this survey recently and only today, as I wa...

The first thing that you should note about this work ( available here ) is that it has almost been a decade in the making. The peculiar object, named Katheryn's Wheel, was first discovered in 2005/6 and the authors have been performing follow up observations and digging up archival data on the object ever since. After first being discovered in the optical region, the authors dug up Near Infrared, Mid Infrared, Far Infrared and Radio observations. The authors also pursued follow up spectroscopic observations of specific regions of the object. I think I should take a step back to give you a look at the bigger picture. Every once in a while, we see galaxies interacting. I'm sure you've heard by now that our own Milky way galaxy and Andromeda are on a path to collide sometime over the next billion years and will end up being one big mess of stars and gas. Similarly, in the past, a lot of galaxies have interacted with our Milky way galaxy. And if we look out into space, we wi...

The first official scientific publication from the data New Horizons has sent back to us got published last week and it's open access, available here . In my opinion, it's fairly accessible to the layman or one who's familiar with the basics of geology and basic science. Broadly speaking, the paper talks about their observations of Pluto and it's three moons Charon, Hydra and Nix. Towards the end of the paper, they also talk about upper limits on size of possibly undiscovered moons and the the properties of a ring system, if any is present while still undetected. Going into the details, they talk about the changes in albedo (reflectivity of a surface) on Pluto's and Charon's surfaces and what the reasons might be. There are also numerous surface features, from ridges to valleys, from craters to mountains, from glaciers to possible sublimation pits. The paper discusses these diverse geological features and their possible origins. The paper also talks about the...

I watched this video  a long long time ago, where Dr. David W. Hogg using images publicly available on the internet to do science. Case in point is this paper they published where they tried understanding the trajectory of the comet 17P/Holmes from astrophotographers' images online. They searched for images of the comet, after it brightened and public interest in it had gone up. They then tagged the images to know what part of the sky they were looking at using astrometry.net . They then did some math, which I will hopefully understand one day, to weigh different images depending on their authenticity and how their metadata of when the images were taken was compared with their predictions of when the comet was in the field of view of the picture. One day. They were, in fact, finally able to reconstruct the orbit of the comet, albeit a slight error. The video mentioned above gives more examples of such, including one awesome example where they rediscover stellar tidal streams ob...

For those who don't know, GMRT stands for the Gaint Meter-wave Radio Telescope. Meter because it observed radiation with wavelength of about a meter or about 300 MHz. Ohkay, with that out of the way, let's talk about the actual paper. If you have been following my blog posts, you will understand why studying faint, irregular, dwarf galaxies is important. Faint dwarf galaxies have very low mass and understanding them will help us understand galaxy formation and evolution in the low mass case. Another interesting thing I learnt from the paper, that should've been obvious to me earlier, is that the gravitational force keeping the (gas in the) galaxy together is about the same as that produced by a few supernovae. The reason they are irregular makes sense now because once these galaxies start forming their first stars, which then go on to explode, the galaxy's gas gets pushed out by the explosions. Also interesting is figure 12 from the paper, that tells us that most of ...

Decadal reports are used as a sort of a road map, a review of the current trends in the field, of what the field is moving towards in the next decade and recommendations put forth which can be used by the governing bodies to dispatch funds appropriately. I have come across decadal reports by the American Astronomical Society (AAS) and by the Astronomical Society of Australia (ASA) but only now have I come across one by the Astronomical Society of India (ASI) Decadal vision document : Astronomy & Astrophysics  (PDF file, 27 MB) I skipped right to the recommendations part and I had my mind blown. Let me give you a brief summary of the recommendations put forth by the committee. 1. Bringing together the community to consolidate work and form Autonomous Working Groups spanning the astronomical research being carried out. The groups can bring together astronomers working on theory, observations and simulations to give a holistic picture. Working groups also help foster...

If large cameras and telescope capable of probing the low surface brightness objects in the sky is one end of the state-of-the-art in astronomy, the following work would be the state-of-the-art at the other end of the spectrum. While surveys focusing on looking at all of the objects in the sky, choosing speed and number of astronomical objects found over spatial resolution, there are telescopes used specifically to study objects at the highest spatial resolution. The paper ( found here ) talks about a narrow, edge-on disk resolved around the star HD 106906 using the SPHERE instrument on the VLT telescope. Note that I used to word resolved and not detected. For an astronomer, those two words are vastly different. The same way dark matter is discovered but not yet observed, astronomers knew that the aforementioned star had a dusty disk around it. How you ask? Well, for starters, if you have dust in front of a light source, the light source looks dimmer. Secondly, whatever light that t...

Well, I guess, if I'm being pedantic, Dr. Jayant V. Narlikar is more of a cosmologist and Dr. Maarten Schmidt is the astronomer, I guess. Moving that aside, they are two heavy weights in their respective professions and we younguns have a lot to learn from them. I came across this autobiography (of sorts) of Dr. Maarten Schmidt wrote for the Astronomy & Astrophysics Annual Reviews journal, It's a beautiful account of his professional life as an astronomers, where all he traveled for the job and a historical perspective on what many astronomical concepts we now consider to be set in stone. While I read the earlier article a long time back, I am only now coming around to post it here because I read this other biography  [1] of Dr. Jayant V. Narlikar and his work by one of his colleagues Dr. Naresh Dadhich. You probably know Dr. Narlikar as one of those scientists who came up with the steady state theory of the universe, you know that theory that competed with the Hot bi...

I am crazy about the Sloan Digital Sky Survey (SDSS). I worked on data from the SDSS for my first summer project. I learnt about SQLquery to acquire data from the SDSS's servers and I learnt Python to do the relevant data analysis. It's an unbelievable treasure trove of data and is in my opinion, the best place to start off if one is serious in pursuing a career in astronomy. Having said that, a while back I was looking at the various institutional members of the SDSS and I found out that there were NO Indian institution involved with the project. None whatsoever. Now, don't get me wrong, I'm sure that there were Indians involved in the project. I'm saying that there was no institutional support meaning that Indian universities weren't funding the project or actively building instruments for the project or had priority access to the data. And it kind of made me sad. The good news now is the fact that India is a 10% partner in the Thirty Meter Telescope (TMT)...

Well, for starters, the DECam is the Camera on the 4-metre Blanco telescope at the CTIO (Cerro-Tololo Inter-american Observatory). It was originally designed for the DES (Dark Energy Survey) but I guess it's also being used for other astronomical observations. The authors are part of the NGFS (Next Generation Fornax Survey) efforts at the CTIO. Coming to the paper ( found here ), the authors give a preliminary report of the 158 new dwarf galaxies they've discovered in the Fornax cluster central regions. There is a lot more science to come out of the data but a preliminary analysis shows that the dwarf galaxies seem to be clustered within the Fornax cluster core, clustering previous predicted in simulations. The authors also fit the surface brightness distribution for each of the dwarf galaxies found to estimate their effective radii. The dwarfs found seem to be fainter and smaller than similar ones (referred to as Ultra Diffuse Galaxies - UDGs) found in the Virgo cluster and...

As I follow the endless path, looking for references in papers, I came across this - the HI rogues gallery . It is a " Collection of maps of HI in Weird Galaxies and Weird HI in otherwise Normal Galaxies " and wow is it a beautiful collection. The whole reason astronomers are interested in HI (neutral Hydrogen) in the universe is because it is the fundamental fuel that makes stars. Also, there's loads and loads of it in galaxies and in the Inter-galactic medium (theoretically).  And in galaxies, this HI extends wayy beyond the boundary defined by the stellar population of the galaxy. This fact can be used to understand the (baryonic) gravitational potential of the galaxy it is embedded in, and the dark matter halo it is embedded in. If you dig through the gallery, you will come across interesting examples showing  intergalactic debris with no optical counterparts ! This is interesting as it helps us understand the history of the galaxies, their environments and the dis...

I've been coming across a lot of work, in the optical and the radio domain to identify and understand dwarf/satellite galaxies, stellar tidal streams and neutral HI (HI is neutral Hydrogen and HII is singly ionized hydrogen i.e a proton) in the universe. This is one of many such efforts (a few of which I will write about later on) where the authors used the SKA pathfinder telescope BETA/ASKAP to observe the galaxy group IC 1459. The full paper can be found here . Let me first tell you why it's a challenge to observe neutral HI in the local universe and why these results are so interesting, IMO. All galaxies form from HI (again, neutral Hydrogen) but once the galaxy/stars start(s) forming, neutral HI close to the sources of radiation get ionized into HII. Only HI in the outer reaches of the galaxy is left unionized. And given that it's at the edge of the galaxy, it's not nearly dense enough to emit strongly. Don't get me wrong, there is still a good amount of HI i...

Well, I got to know a couple of days back that there was a Lunar-based Ultraviolet telescope. I finally got to read the paper today ( that can be found here ) and it's quite interesting. For those of you who remember, the Chinese landed a Lander on the moon and tried sending a rover on the lunar surface (which quickly failed). Apparently, that Lander had a UV telescope on it. As soon as I read the abstract, the first questions that came to my mind was when exactly they observe. If you think about it, we see the moon at night because it reflects the sun's light meaning that if it's night time for us, it is day time on the moon. The same way, if I were on the moon, I'd be able to see the earth because it will reflect the sun's light. Astronomers on earth prefer moonless nights because the night skies are darker. In the same way, the lunar based telescope had to take into account the fact that earth shines bright at night time when designing their telescope and plan...