Dark Energy Spectroscopic Instrument (DESI)

Srivatsan Sridhar

by

pfagrelius

What is your position or role in the DESI project?
I am a postdoctoral researcher at the Korea Astronomy and Space Science Institute.
My main research topic is large-scale clustering analysis, with a special focus on Baryon Acoustic Oscillations (BAO).

Where were you born?
I was born in Madras (now Chennai), the capital city of the state of Tamilnadu, in India.
Fun fact: The Marina beach in Chennai is considered the world’s second longest urban beach !

Where do you live now?
I currently live in Daejeon, which is South Korea’s fifth-largest metropolis.
Fun fact: Daejeon has earned it’s name as “Asia’s Silicon valley”.

What do you do as part of DESI? The DESI part of my work involves analyzing the large-scale clustering from DESI like simulations. Each object that will be observed via DESI will be assigned a “priority”. I am, in particular, trying to find out the effects that these “priorities” will have on the large-scale clustering. I am also working on trying to recover the BAO signal from photometric catalogues and compare it’s accuracy with the same obtained from spectroscopic catalogues.

What is the most interesting or exciting thing about DESI? From my perspective, as a junior scientist, being part of DESI gives me the opportunity to meet and discuss my work with many veterans and influential people from my field. From a scientific perspective, the fact that DESI will be covering 14,000 sq degrees and going to deeper redshifts gives all cosmologists a hope that the influence of dark energy on the expansion history of the Universe can be studied in more detail than ever before.

What do you do for fun?
I am an avid football (my fellow Americans, it’s not soccer!) and cricket enthusiast. Hindu philosophy and archaeology are some of my other interests.

What is your position or role in the DESI project?
I’m a Manufacturing Coordinator for the mechanical engineering department at Lawrence Berkeley National Laboratory and I currently support the DESI fiber assemblies, positioners, petal, and science cable splicing full-time.
Where were you born? 
I was born in Dallas, TX where I lived my entire life until moving to California.
Where do you live now?
I moved to California in 2014 and I live in Emeryville (right next to Berkeley and Oakland).
What do you as part of DESI? (both generally and day-to-day activities)
For all of the assemblies I cover I make sure procedures are documented, people are trained, and quality checks are in place. Daily I create work assignments for the manufacturing team to meet our schedule requirements.
What is the most interesting or exciting thing about DESI (and/or your job and/or astronomy in general)?
The range of assemblies I support means there is always a new challenge. I’m very excited about the eventual science this complex instrument will yield.
What do you do for fun? 
For fun I enjoy cooking, and being out in nature spotting birds and animals while hiking.

What is your position or role in the DESI project? I’m a junior researcher at the University of Guanajuato. I was recently appointed to be co-chair of the Lyman-alpha working group.

Where were you born? I was born in Metepec, a small town in Estado de México in  México country. This town is nowadays considered a “Pueblo Mágico” (Magic or charming town)

Where do you live now? I’m now based at León city in the state of Guanajuato. It is very close to Guanajuato, one of the most beautiful cities in México. Interestingly León, and Guanuajuato,  host many international events annually, like a Ballon festival, the Rally, and the Cervantino, just to mention some.

What do you as part of DESI?  As co-chair of the Lyman-alpha WG I’m starting to help coordinate the WG tasks.  I also test and help to improve some of the code used in the WG. For example, I’ve been working with  the code that will be used to determine the quasar redshifts, using it in simulated quasars, where we know the truth, so that we can know how well this codes performs. I also help graduate students, mostly from  the University of Guanajuato, to develop their projects within DESI.

What is the most interesting or exciting thing about DESI? For me the most intriguing aspect of astronomy/cosmology is the nature of Dark Energy and  Dark Matter. Contributing to know more about this two mysterious components of our Universe is just astounding.  Even though DESI is mostly focused on Dark Energy (as the name says so), the gathered information will also be very helpful to understand Dark Matter. Now that I’m closely following the status of the project I realize how much work is involved, and that is truly a huge effort from many people. I’m so excited about all the science and knowledge that is being developed every day. 

What do you do for fun? I walk my dogs, morning and afternoon. I enjoy having BBQs and cooking  at home, specially if we have friends over. I’m really interested in the popularization of science, for girls mostly, so I dedicate some of my free time to a community, where we organize and give small workshops, talks, and  science shows. I hope some of them in the future will become scientists.

What is your position on DESI? I am a PhD student at CEA Saclay working on two aspects of DESI project, namely the selection of the quasar targets as well as the integration and testing of the cryostats fitted to the spectrographs.

Where were you born? I was born in a town called Montluçon in central France.

Where do you live now? I currently live in the south of Paris, not far from my workplace.

What do you in your position on DESI? I work on the selection of quasar candidates, the more distant objects that will be observed by DESI, based on their photometry properties by making use of machine learning tools. I am also in charge of developing an optical bench in order to validate the accuracy of the positioning of the CCD sensors mounted within the crysotat vessels. Basically, an array of microlens is used to project very precisely a grid of spots on the CCD. Then, we are able to infer the possible misalignment of the CCD according to the observed distortion of the grid of spots.

What excites/interests you most about DESI? As a PhD student, DESI is a great opportunity to get a comprehensive overview of a large-scale science project conducted within an international collaboration. Moreover, my thesis related to DESI gets me involved in activities covering several disciplines ranging from data analysis, computer simulation to optics and mechanics.

What do you for fun? I like going back to my beautiful home region, in Auvergne, to see my family and my friends, do mountain hiking and biking and enjoy the local gastronomy.

What is your position on DESI? I am a junior scientist in the DESI collaboration and part of the Milky Way Survey group. My current role is to produce software that will help calibrate the spectra that DESI collects by using stellar remnants known as “white dwarfs.”

Where were you born? I was born in a town called Sidcup in the United Kingdom.

Where do you live now? I currently live in Coventry in the United Kingdom, and work at the University of Warwick (which is in Coventry, not Warwick!).

What do you in your position on DESI? I work with the Milky Way Survey and the Data team to use white dwarfs (the cores of dead stars once they finish fusing Hydrogen and Helium) to help calibrate the spectra that will be obtained by DESI. These white dwarfs have relatively simple spectra, which make them great calibrators. This involves writing a lot of code and analyzing simulated DESI observations to ensure we have the best calibration possible!

What excites/interests you most about DESI? Doing research in astronomy has given me the ability to travel to amazing places to collect data, such as the island of La Palma in the Canary islands, or Kitt Peak to observe at the Mayall telescope. My research interests are mostly involved with white dwarf planetary systems. It is thought that up to half of all of these stellar remnants will still host planets, and we can use these systems to learn about the composition of asteroids and comets from other planetary systems. With the help of DESI, we will find more of these systems, and answer questions such as: What will happen to the solar system when the Sun runs out of fuel? Are the rocky bodies in our solar system standard or unusual?

I think one of the most interesting parts of DESI is the focal plane, with over 5000 fiber robots that will be automatically repositioning themselves while avoiding each other to allow us as observers to efficiently observe millions of sources in the night sky.

What do you for fun? I enjoy playing a lot of games: Video games, board games, Dungeons and Dragons! I also like to play Go (you may have heard of AlphaGo), practice in power-lifting, and have recently started using “perler” beads to make pixel art!