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DESI commissioning has raced forward this winter, and we have now
demonstrated the key performance parameters of the instrument!
Since installation of the instrument, refinement of the performance of the 8 square
degree corrector, high-precision (10 micron) positioning of the
fibers under active feedback, accurate calibration of the spectrographs,
and on-sky commissioning of the whole user interface have been demonstrated.

All of this progress culminated in successful demonstration in March
of spectroscopy with the full DESI system of many tens of thousands
of survey targets. The image below is of a luminous red galaxy targets, easily revealing the distinctive Balmer-line signature of a post-starburst galaxy at redshift 1.286! See our blog for more details!

DESI commissioning has raced forward this winter, and we have now demonstrated the key performance parameters of the instrument! Since installation, refinement of the performance of the 8 square degree corrector, high-precision (10 micron) positioning of the fibers under active feedback, accurate calibration of the spectrographs, and on-sky commissioning of the whole user interface have been demonstrated.

All of this progress culminated in the successful demonstration in March of spectroscopy with the full DESI system of many tens of thousands of survey targets. We have observed spectra of faint galaxies and quasars with redshift distributions and spectroscopic signal-to-noise that match well to what we expected.

Here is the infrared spectrum of one of our early luminous red galaxy targets, easily revealing the distinctive Balmer-line signature of a post-starburst galaxy at an impressive redshift z= 1.286. This galaxy is magnitude 19.9 (AB) in the z-band, about a factor of 2 brighter than our planned flux limit. DESI observed this target for 45 minutes on March 15. The spectrum has been smoothed for presentation.

Unfortunately, as it is with so many around the world, the COVID-19 outbreak is forcing us to adjust our plans. We’re taking a break from on-sky observing until it is easier for our collaboration members to travel safely to Arizona. But we’re fortunate that this winter’s commissioning produced so much data that we can work on it, in the meantime. DESI will be back, we hope soon, with continued momentum toward our next goal of validating the survey design.

This target was selected from the Data Release 8 of the DESI Legacy Imaging Surveys (Dey et al., AJ, 157, 168, 2019); the object is shown in the center of the small image here, formed from the g, r, and z-band images.

Due to growing travel restrictions and concerns regarding the COVID-19 outbreak, the DESI2020 Collaboration Meeting, originally scheduled for March 9-12 in Tucson, AZ, was held completely remotely. The online format of the meeting was very successful and many important discussions centered on early data from commissioning and preparing for the upcoming Survey Validation.

The picture shows a small group of collaboration members that were “stranded” in Tucson before travel restrictions were put in place. They practiced social distancing in the Sonoran Desert!

What is your position or role in the DESI project?

I am one of the telescope operators at the 4meter/Mayall telescope.

Where were you born?

Originally born in Cali, Colombia. I moved to Florida in the fall of 1998. After high school, I moved to Gainesville, FL to attend the University of Florida. After college, I stayed in Gainesville working as a graduate research assistant in the astronomy department working in different projects including extra-solar planets, extragalactic evolution and AGN. I also took graduate courses (non-degree seeking) in aerospace engineering. I then moved to Arizona in the Summer of 2013.

Where do you live now?

Tucson, AZ.

What do you do as part of DESI?

As part of DESI, I am a telescope operator at the Mayall. I assist visiting astronomers with their work on DESI. I am primarily responsible for the control of the telescope making sure pointing is correct, the telescope systems are working properly and the telescope is slewed safely across the sky. I am responsible for the overall safety of the telescope and observatory facilities. I also contribute to documentation for telescope operations and safety. I am experienced with technical support for the telescope and its systems. Depending on the night, I might be asked to run tests for the engineer group.

What is the most interesting or exciting thing about your job?

The most exciting thing about my job is the opportunity I get to work with different astronomers, scientists and engineers from different backgrounds and expertise. As a telescope operator at KPNO, we are also asked to operate the 3.5m/WIYN telescope, and as such, we get to work on a variety of science projects during our 6 night shift. One night we might use a spectrograph on clusters, then switch to an imager to follow asteroids and then finally head to the Mayall to work on DESI. It makes our job very fun and interesting. On bad weather nights, we might also get the chance to host visitors from the public night program. It is a great opportunity to show them our work with first hands on experience of our control room and the telescope itself.

Any advice for an aspiring scientist?

Get involved early and try to work on different projects doing a variety of science. You might not know what really drives you until you try it! Perhaps you have always been interested in the solar system, but what if you give your self a chance at working with an infrared instrument to unveil the most massive galaxy clusters in the universe? or do spectroscopy of ultra-low metallicity star-forming galaxies? During this time you can find out where you can best use your skills: you can work in Scientific programming, instrumentation, data analysis, or observing techniques. Last but not least, never stop asking questions!

What do you do for fun?

On the days that I am off duty from the observatory, I work as a substitute teacher at Desert View High School in the Sunnyside Unified School District of Tucson, AZ. I am also the assistant coach for the boys’ soccer team. As a substitute teacher, I get assigned to all subjects from Math to English and Spanish to Art. I work with 9-12 grades but mostly enjoy working more with the upper classes. Being a substitute teacher (and coach) has been one of the most rewarding experiences of my life. I use this opportunity to be a good role model for the kids and be a strong advocate for science and the work we do at Kitt Peak. It is very inspiring to see the kids get interested in science and astronomy whenever I tell them what I do for a living. In my spare time, I enjoy spending time with my family and I like to play soccer, run and hike the Sabino canyon. I also enjoy dancing.

What is your position or role in the DESI project?

Having been a DESI member as a graduate student for four years, I became a postdoc at Boston University Physics Department months ago, working on instrument commissioning, primarily the focal plane system.

Where were you born?

I was born and raised by middle-class parents in Tianjin, China, a harbour city next to Beijing. I came to the US in 2009 to attend a liberal arts college hoping to enjoy greater freedom and a more nurturing academic environment. In 2013 I moved to Boston for graduate school, where it has become my second hometown.

Where do you live now?

I have been living in the Boston area for over six years and really enjoying the life here. It is intellectually stimulating and culturally vibrant. The diversity in New England is impressive, always possible to meet people with similar interests or visions. There is a world-class symphony orchestra as well as an abundance of shows of nearly all types. Massachusetts prides itself on carrying the spirit of America from the colonial past through the civil war to the present day, and the New England states have been taking the lead in defining the structural reforms this country needs in order to evolve and stay in the economic, technological, and moral high ground on the world stage. There is also a special sentiment to be found in the nostalgic English names of local towns.

What do you do as part of DESI? (both generally and day-to-day activities)

Over the past four years, I have worked on a variety of things within or related to DESI involving very different skills which all become part of a physicist’s bag of tricks. I started out helping build ProtoDESI at Berkeley Lab, a proof-of-concept focal plane instrument consisting of only 3 fibre positioners. A fibre photometry camera (FPC) was installed at the output ends of the optical fibres in place of spectrographs, and I characterised the FPC and analysed its data after a successful run at KPNO.

Then Boston University’s machine shop (Scientific Instrument Facility, SIF), with its proven track record and unbeatable price, got the contract to fabricate the DESI focal plate structure, on a tight schedule and within micron-level tolerances. My advisor Prof. Steve Ahlen and I worked hard with the machinists to refine the quality of the petals, found the right coating, and measured 100% of the critical dimensions of each petal on a Zeiss CMM with an automated CMM programme we developed together with Zeiss.

These focal plane metrology data were instrumental in our later alignment of the focal plate structure, as each petal is machined slightly differently and needs to be individually adjusted when bolted to the integration ring. At the end of the alignment, my colleagues and I achieved around 99.9% projected optical throughput using another CMM at Berkeley Lab, meeting the micron-level precision requirement and science requirement of the project. I was also an active observer for MzLS of the Legacy Surveys.

Having completed and delivered the focal plate structure for integraiton with the robotic fibre positioners, I started working with Prof. Daniel Eisenstein at the Harvard-Smithsonian Center for Astrophysics on a halo occupation distribution (HOD) forward-modelling project with significant implications for surveys like DESI. This was a terrific opportunity for me to embrace the theoretical and computational side of observational cosmology. We employed high-fidelity N-body cosmological simulations, created a number of mock galaxy catalogues, and determined the systematics due to the HOD parameters assumed in measuring baryion acoustic oscilaltions (BAO), a key signature in large-scale structure.

Recently I have been working on petal assembly testing, positioner calibration, and essentially software development for instrument control, monitoring, and analysis. My day-to-day activities include attending telecons, coding, running focal plane tests, supporting DESI commissioning tasks, and travelling to KPNO for day and night shifts from time to time.

What is the most interesting or exciting thing about DESI (and/or your job and/or astronomy in general)?

DESI has great potential to make the next big discovery in cosmology and particle physics. 35 million galaxy spectra is an unprecedented order of magnitude for this sort of data, only achievable with the state-of-the-art DESI positioners. It is extremely exciting and fortunate for me to be able to contribute to this project. I don’t have to describe how or why fundamental physics is interesting or exciting. To me DESI is the perfect blend of cosmology, particle physics, and astronomy, and my work has had the right balance between software and hardware.

What do you do for fun?

There is a vast universe of fun to be had in books, music, and films. They not only provide fun, but also make me relax and contemplate. I am also an amateur music producer, racing driver, and lapsed pianist. In the old days I used to be a cyberathelete playing competitive Counter-Strike and e-sports commentator.

What is your position or role in the DESI project?
Safety Manager for Kitt Peak/on-site DESI

Where were you born?
Hanover, NH

Where do you live now?
Arizona City, AZ

What do you as part of DESI?
I try to make sure everyone has what they need for safety equipment, as well as, review procedures and plans to make sure that safety concerns are addressed.

What is the most interesting or exciting thing about DESI?
For me, the most interesting thing is working with a diverse group of people and watching how well they all work together as a team. It has been a learning experience to help meet the needs of the various folks working at Kitt Peak.

What do you do for fun?
My husband and I are both Hot Air Balloon pilots – so we have fun flying our balloons in various locations throughout the world and meeting people from all over. It is so much fun to watch a smile come over someone’s face during our flight.

DESI Opens It’s 5,000 Eyes to Capture the Colors of the Cosmos!
Full press release here

What is your position or role in the DESI project?
I am a senior scientist at Fermilab. I am responsible for a program called “PlateMaker” that is part of the instrument control system.

Where were you born?
I was born in the town of West Orange, New Jersey, where Thomas Edison had his laboratory and built the first movie studio.

Where do you live now?
I live in the town of Geneva, Illinois, close to Fermilab. It is a scenic town with many shops, restaurants, bike trails, and an authentic Dutch windmill.

What do you do as part of DESI? The PlateMaker program maps the positions of galaxies on the sky to the DESI focal plane and tells the fiber positioners where to move. Because the DESI corrector introduces a large amount of distortion, the mapping
requires understanding the corrector properties to high accuracy. While the corrector was being fabricated, I was part of the optics team, evaluating the impact of things like glass homogeneity and polishing errors on our eventual ability to accurately position the fibers.

What is the most interesting or exciting thing about DESI? You never know where your work will lead you. In order to model distortion patterns in the corrector, I developed some new mathematical techniques that turned out to be similar to those used to analyze the microwave background polarization and gravity waves. I wrote this up as a journal paper, and it is the second paper to be published by the DESI collaboration.

What do you do for fun?
I enjoy hiking, “peak-bagging,” and other outdoor activities. I also spent time trying to predict the location of where Malaysian Airlines Flight MH370 disappeared (not yet found).

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!

DESI Successfully Completes Commissioning Phase

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