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What is your position or role in the DESI project?
I’m a postdoctoral fellow who works mostly in the Clustering, Clusters, and Cross-correlation as well as the Galaxy and Quasar Clustering working groups.

Where were you born and where do you live now?
I was born in Fremont, California, and have lived my entire life in various parts of the San Francisco Bay Area. I currently live in Oakland, and work at Lawrence Berkeley National Laboratory, which sits just up the hill from UC Berkeley’s campus.

What do you do as part of DESI?
I run computer simulations of how structure in the universe forms assuming different scenarios for what the universe is made of, and then compare those simulations to the data that DESI is taking. In doing so, we can learn about the mysteries of dark matter and dark energy. The hard part of my work is figuring out how to compare my simulations, which are highly idealized, to the highly complex data that DESI gathers. One challenge related to this is that my simulations include only dark matter, while the galaxies that DESI is observing are composed of luminous matter, like us. This is a very fun problem to tackle, as it involves building models for the connection between dark and luminous matter. On any given day, I use a combination of high-performance computing, statistical techniques and analytic theory to make progress on these problems.

What is the most interesting or exciting thing about your job?
I love how many different fields of science and technology I get to use in order to solve problems. Some days my work is entirely computer programming, others I get to work on fun statistical problems, and others still are spent reading technical physics theory papers and working out derivations of my own. I also truly enjoy collaborating with and learning from a broad range of colleagues who all bring their own expertise and perspectives.

Any advice for an aspiring scientist/engineer?
My advice is two-fold: First of all, pursue your passion. I have found that I am far more effective at working on something whose goals I believe in wholeheartedly. Intrinsic motivation is so much more powerful than extrinsic pressure to perform. In order to find intrinsic motivation, it’s very important to maintain an open and curious mind. Sometimes the things that are most interesting can take you by surprise. Secondly, learn as much math and programming as possible. These skills are necessary for virtually all science and technology, and so by learning as much of them as possible, you will open many doors for yourself.

What do you do for fun?
I love the outdoors. The San Francisco Bay Area, with its hilly topography, is a great place for road biking. I also enjoy backpacking and skiing in the nearby Sierra Nevada mountains. I’ve played basketball for my entire life and while I don’t play much anymore due to various accumulated injuries, I am still a big fan of the local professional basketball team, the Golden State Warriors.

What is your position or role in the DESI project?
I have being working in different working groups and participating in different tasks since 2015. Now I am mainly involved in the galaxy clustering and Cosmo Simulation working groups, but some time ago also contributed to some tasks of C3. Since 2019, I am co-leading the DESI Mock Challenge with Shadab Alam and Albert Chuang. I am leading the Mock Challenge in Reconstruction and Baryonic Acoustic Oscillations. Also, I am currently the chair of the meetings committee and I participate in the DEI committee as the liaison with the meetings committee but also because I am interested in inclusiveness and equity in academy.

Where were you born and where do you live now?
I was born in Mexico City. I did my bachelor’s in Facultad de Ciencias UNAM. Then I did my graduate studies in France (Universite Paris-XI and then Universite Paris VII in Laboratory APC). After finishing my studies I moved to the US in Pittsburgh, where I did a post-doctoral position in Mc William Center of Cosmology at Carnegie Mellon University. Then I came back to Mexico City where I am in a tenure track position for the past 7 years at Instituto de Fisica at UNAM.

What do you do as part of DESI?
I am working on the main observables of DESI: BAO and RSD. I am now co-leading the Mock Challenge and in particular I’m coordinating the Mock Challenge of Reconstruction and BAO. Currently I am focused on working on the publications that summarize two years of this effort. I am also helping in the preparation of SV3 mocks, in particular applying the FA to those mocks with the footprint of Year 1. I am also co-advising several students of our group of Observational Cosmology at UNAM to participate in DESI. For the last 2 years I worked with a masters student on the effects of Fiber Assignment with simulations and exploring mitigation techniques with LRG, and now working on the pipeline to apply the fiber assigning to mocks. I am currently co-advising a graduate student for participating in the RSD mock Challenge and another graduate student participating in the BAO mock Challenge. Also, I am working with another graduate student on the generation of simulations with non Gaussianities and their analysis in the context of DESI. Another student of our group is working on the effect of massive neutrinos in the large scale structure with the goal to apply this to DESI and potentially 2 more students will start soon as well to work on another project related to forward reconstruction in the context of DESI.

What is the most interesting or exciting thing about your job?
I really enjoy working within collaborations, I’m very happy to be able to discuss with experts in the field weekly I consider there is a lot of interaction and community feeling. I like the possibility to meet people from different parts of the world and different experience and expertise. I grown within these large collaborations my whole academic life, for me, the collaboration is like my academic family. I learned from the experts when I was a graduate student in the BOSS times, then I became a postdoc and I continued working and learning in the context of BOSS. I increased my network of collaborators thanks to the constant interaction within the collaborations as a postdoc. Now as a junior assistant professor I am trying to transmit my knowledge acquired over the years and potentiate the development of the early career scientist and also continue learning as a medium career scientist I consider myself.

Any advice for an aspiring scientist/engineer?
Collaborate with others, science is a collaborative effort. Collaborations are a great environment to learn and interact with experts all over the world, profit of this network of experts, ask as many questions as you want, scientist are always learning, do not be shy or be shamed of asking questions, join projects, try new ideas, have fun with research now and worry less about the future, you will define your way as you walk through it. Open all the possibilities and never close a door.

What do you do for fun?
I like to practice yoga and dance. I also like biking, hiking in the mountains and running. I started boxing lessons recently, and zumba but also I am trying to go the gym more often. When I have time I like to cook, and garden. I also have a violin and I would like to learn how to play it one day, I like to sing but I am not that good (it seems). I also have two big dogs always willing to play and walk the streets of the busy Mexico City.

What is your position or role in the DESI project?
I’m a postdoc at the University of Utah. My formal DESI role is interim co-chair of the collaboration’s Education and Public Outreach committee.

Where were you born and where do you live now?
I was born and grew up in Portland, Oregon. I now live in Salt Lake City, Utah, but before that I called California home for over 15 years.

What do you do as part of DESI?
Primarily I work on creating mock galaxy catalogs for characterizing the DESI luminous red galaxy (LRG) sample and (hopefully) improving models of small-scale galaxy clustering. I also did a lot of visual inspection of LRG spectra in preparation for the main survey, and do the occasional remote observing shift as a Support Observer. A big part of my role on the collaboration’s Education and Public Outreach committee is updating the public DESI website (where you’re reading this now!). I’m starting to work on the pages that will announce DESI science results and data releases as they become available.

What is the most interesting or exciting thing about your job?
The data I use in my research comes from light that has traveled halfway across the observable Universe (OK, not quite that far, but still astounding!). I’m continually amazed that humanity can unravel the history of the cosmos itself with just ancient photons that survive the journey to our telescopes. We’re such a tiny speck in an incomprehensibly vast universe that it doesn’t seem it should be possible, but it is!

Any advice for an aspiring scientist?
There isn’t one right path you must take to become a professional scientist. College was challenging for me, so much so that I didn’t apply to graduate school right away. Even though I’d wanted to be an astrophysicist ever since I learned that’s an actual job, college left me seriously questioning whether I had what it takes to succeed in grad school. It was several years before I rediscovered the resolve to apply and built up the experience to craft a successful application.

Also, while easier said than done, don’t be intimidated by what you don’t yet understand or the skills you don’t yet have.

What do you do for fun?
I like to cook and bake, “train” for half marathons, and explore the abundant natural beauty surrounding Salt Lake City. Occasionally I even find time to work on my latest craft project: a cross-stitch of a spiral galaxy that I started over two years ago. If I thought I could make a living at it, I would be an artist who focuses on abstract geometric sculptures.

What is your position or role in the DESI project?
I am a graduate student at UC Irvine working toward my PhD. In DESI, I am part of the Lyman-alpha Forest working group and I am one of the Lyman-alpha quasar catalog co-leads. I am also part of the DESI mentoring program as both a mentor and a mentee.

Where were you born and where do you live now?
I grew up in Center Line and Warren in the metro-Detroit area of southeast Michigan, and I did my undergrad at Wayne State University in Detroit. I now live in Irvine in Southern California. Sometimes I miss having seasons and snow but my recent trip to Michigan brought me back to reality.

What do you do as a part of DESI?
I recently started a project to study the impact of quasar redshift errors on the 3D cross-correlation of quasars with the Lyman-alpha Forest. As one of the quasar catalog co-leads I am helping to put together a quasar catalog that will be used for future Lyman-alpha science analyses. I am also interested in using these quasars to study baryon acoustic oscillations (BAO). Previously, I helped out with commissioning by looking at GFA calibration data, and I’m hoping to get more involved with the focal plane team in the future. I’ve also done some observing shifts in the past, and am looking forward to more shifts in the future!

What is the most interesting or exciting thing about your job?
As a graduate student, I am always learning new things. Being a part of a collaboration like DESI also means that I get to travel, meet people, and make friends from all over the world! I always thought my career path would be pretty straightforward: get my PhD, do a postdoc, get a job at a university. I’ve learned though, that there are so many different opportunities and different paths I could take within astronomy/astrophysics that don’t necessarily involve teaching and are all very interesting. Good thing I’ve got a few years before I really need to decide!

Any advice for an aspiring scientist/engineer?
There is a lot of great advice from other DESI members but one thing I think is extremely important is that you don’t have to do science 24/7 to be a great scientist! It’s very important to set boundaries and take breaks to find and maintain a good work/life balance. Some people enjoy using their free time to work, others don’t, and both are okay! You have to find the right balance for you. Also never be afraid to ask questions as there is no such thing as a dumb question! A tip: if you don’t want to ask in front of other people you can usually ask your questions in an email after the talk or lecture. Finally, learn to code.

What do you do for fun?
Outside of DESI and my PhD I enjoy spending time with my friends and family. I love going to hockey games, especially when the Detroit Red Wings come to town. I try to watch every game when they’re not in town. Within the last year or so I’ve taught myself to crochet and I am currently trying to teach myself to knit. I also like to build puzzles, play video games, complete paint by numbers, and I’m hoping to start baking more in the upcoming year.

What is your position or role in the DESI project?
I currently work with the Operations team on tasks related to the targets that DESI observes.

Where were you born and where do you live now?
I was born in Newcastle-Upon-Tyne in the UK. People from Newcastle are colloquially referred to as “Geordies” so if you see an email address, Slack handle, or GitHub conversation related to DESI that includes the name “geordie,” that’s probably me. I currently live in Laramie, Wyoming, which is a beautiful mountain town near the Colorado border, about two hours north of Denver.

What do you do as part of DESI?
Prior to the start of DESI operations I wrote much of the “desitarget” software package used to determine the catalogs of targets that DESI would follow up. A lot of my focus, now, is on maintaining the ledgers that track which targets DESI has observed, the redshift of each observed target, and how many more observations we need of each target given its current observational state. Tracking targets in this manner is particularly important for quasars, for which we want additional observations if they can be used for studies of the Lyman-alpha Forest. I also contribute new code to desitarget for other goals related to targeting, such as observing new special targeting classes, and creating random catalogs that mimic the footprint of the imaging surveys from which DESI selected targets. Basically, I write and maintain a lot of software!

What is the most interesting or exciting thing about your job?
I love writing code and I love working in a large collaboration. It’s exciting to see years of careful planning come to fruition—for instance, when we started to obtain spectra for large numbers of targets during the DESI Survey Validation phase and confirmed that we were targeting the expected numbers of cosmological tracers. I find it particularly interesting to interact with experts who have a plethora of complementary skills (instrumentation, computation, theory, observation, etc.) and with a wide range of science goals. It’s also satisfying to see people using, and improving, code that I initially wrote, and to be contacted with questions about how or why DESI adopted certain targeting strategies. Basically, it’s a lot of fun to be part of a team of people working on a common project.

Any advice for an aspiring scientist/engineer?
Get involved. I think it’s important to realize that every contribution, no matter how small it might seem, is needed and appreciated. Even if you don’t, ultimately, end up with the job you expect, it’s amazing to be able to say that a major experiment to study the Universe achieved some of its goals because of something you did. So, jump in and volunteer to write code or serve on a committee. Like with any job, networking is important to becoming a professional scientist. So, try to work on projects with a number of different colleagues and try to take the opportunity to socialize with new people at collaboration meetings. I can identify several meetings in my career where I almost didn’t attend and I wound up having dinner with people with whom I still collaborate ten-to-fifteen years later.

What do you do for fun?
I hike as much as possible. Laramie is only an hour-and-a-half from Rocky Mountain National Park, and is an easy day’s drive from multiple other national parks in Wyoming and Utah. Plus, there are any number of amazing locations in the Rockies that are off the beaten track. It’s a really beautiful part of the world.

What is your position or role in the DESI project?
I am currently a postdoctoral fellow at Shanghai Jiao Tong University, which is an institutional member of DESI. In terms of my role within DESI, I’m an active member of the c3 working group and one of the co-organizers of the galaxy cluster analysis within c3. I also served as a member of the secondary target selection review committee for the DESI SV and Y1 data.

Where were you born? Where do you live now?
I grew up in Saratoga Springs, NY. I did my undergrad at Brown University and my Ph.D. at the University of Michigan. I’m currently living in Shanghai, China, where I work at Shanghai Jiao Tong University.

What do you do as part of DESI?
I am working with DESI data to study galaxy evolution within cluster environments. The first of these projects is constructing a complete sample of SDSS-redMaPPer clusters from DESI observations to understand projection effects on cluster membership. The second is a study of the stellar outskirts of massive galaxies using DECaLS data as a proxy for identifying clusters. Additionally, I’m participating in the remote observing effort for DESI, which I’m very excited to do!

What is the most interesting or exciting thing about your job?
I love that Astronomy allows me to ask and investigate the big questions. As much of my research is related to galaxy evolution, I love exploring the past to look at massive galaxies at different points in cosmic time in order to understand the physical scenarios that have led to the observations that we currently see. Because Astronomers don’t have the ability to watch individual galaxies change over time, I really enjoy using our snapshot images of different galaxies to construct a rough evolutionary pathway to estimate how massive galaxies evolve.

Any advice for an aspiring scientist?
Make sure to find good and supportive mentors. Especially in graduate school, it’s very important that you find a mentor that you can work well with and who supports you both as a person and as a scientist. From my experience, it’s incredibly important to build a network of mentors and collaborators that you can go to for help and advice, whether it’s research advice, job advice, or life advice. I think it’s also important to remember that these mentors don’t have to be located at the same University you are or work in the same sub-field of Astronomy that you are working in.

What do you do for fun?
When I’m not working on the many different astronomy projects that I’m currently involved in, I enjoy running in different parts of Shanghai, reading comic books and manga, and cooking delicious vegan food and baked goods!

What is your position or role in the DESI project?
I am a Senior Engineer and a part of the Engineering Services group for NOIRLab at Kitt Peak National Observatory. We take projects from inception, through the design phase, all the way to implementation. This was a major part of preparing the Mayall 4 Meter telescope for the DESI Instrument and Survey.

Where were you born? Where do you live now?
I was born and raised in Tucson, Arizona. Currently I live in Tucson, Arizona.

What do you do as part of DESI?
For the last couple of years, I was one of the leading members with installing and implementing a complete transformation of the Focal Plane. This included removing the original top ring, assembling the new top ring, installing it on the telescope and implementing all the necessary components associated with the DESI instrument. Moving forward we will maintain the instrument and the telescope to keep science being produced at its peak with this instrument.

What is the most interesting or exciting thing about your job?
The most exciting thing about my job is the fact that we are always doing something different. Because this telescope is out of the 60’s, most of the components are one off pieces. We are constantly having to retrofit new technologies for anything that has failed. Plus, you cannot beat the office views, being on the highest peak in the area.

Any advice for an aspiring scientist/engineer?
My biggest advice for any aspiring scientist or engineer, don’t be afraid to ask questions, immerse yourself and get stuck. I learned the most from going all in and taking on projects that truly take you out of your comfort zone. Often, you can be afraid to take something on thinking “I have no idea how to do this”, but you will surprise yourself.

What do you do for fun?
I absolutely love winter sports, the snow, and snow skiing. It’s truly when I am in my element! I spend a lot of my winters skiing, and I spend a lot of my summers traveling, camping and exploring trails!

What is your position or role in the DESI project?
I am currently a third year graduate student at Stanford leading analysis on the DESI LOWZ Secondary Target Survey.

Where were you born? Where do you live now?
I was raised in Marin County in California and am currently living in Palo Alto.

What do you do as part of DESI?
I mainly work on analysis for the LOWZ survey. I am interested in understanding the properties and histories of nearby low redshift dwarf galaxies. I have worked on the survey since its conception, through the process of target selection, and am now heading the analysis of the SV3 and early main survey data. I am interested in how nearby dwarf galaxies can help us understand the formation histories of dwarf galaxies within the Milky Way.

What is the most interesting or exciting thing about your job?
I enjoy the problem solving aspect of computational astrophysics. I like the process of going from a project’s conception to understanding how to efficiently implement the analysis in code. I also like the intimacy of low redshift analysis where I can come to know the objects I work with as individuals. Lastly, I have always deeply valued the social aspects of science. Getting to collaborate and just hang out with my colleagues at all career stages is always a daily highpoint.

Any advice for an aspiring scientist?
Have fun! As a scientist, it is easy to get caught up in the stress about your performance, knowledge, or career advancement. While these aspects all matter, they can easily overshadow the reasons one gets in to science in the first place—a desire for knowledge and curiosity about the world. Remember to take time to reflect on how awesome the work you are doing is. Contributing to the project of human exploration is valuable, even if you are just an elementary school student working on your first science experiment. Don’t listen to anyone who tells you that you are not good enough, and strive to find people who remind you why you love science rather than make you feel like you don’t belong.

What do you do for fun?
For fun I enjoy cooking, writing, and drawing. I also love hanging out with close friends over good food and good wine surrounded by interesting conversations. I am an avid consumer of podcasts and leftist YouTube channels and love learning about topics outside of astrophysics from literature to history. I am currently supplementing my graduate school course load with an excellent course on Victorian poetry. Before COVID, I also enjoyed going out to see live theater in the Bay Area.

What is your position or role in the DESI project?
Executive Coordinator for NSF’s NOIRLab Mid-Scale Observatories / Kitt Peak Directors office.

Where were you born?
Florida

Where do you live now?
Tucson, Arizona

What do you do as part of DESI?
I provide administrative support including planning of DESI reviews and collaboration meetings, logistics, lodging and safety support along with procuring miscellaneous supplies as needed for the Kitt Peak DESI team.

What is the most interesting or exciting thing about your job?
The most interesting thing is interacting with people of all cultures, backgrounds and skill sets. I feel very honored and privileged to be able to work on the beautiful, magical Tohono O’odham land.

What do you do for fun?
I enjoy remote camping and exploring the deserts and forests of Arizona with my husband and three (adult!) kids.

Victoria Fawcett, Durham University

July 22, 2021

As the main DESI survey gets truly underway, I want to reflect on the amazing quality of the DESI quasar spectra observed so far. Quasars are incredibly luminous types of Active Galactic Nuclei (AGN), which consist of a supermassive black hole at the centre of galaxies, surrounded by a disc of matter that often outshines the entire galaxy. Quasars are one of the brightest objects in the Universe and are really important in all areas of Astronomy, especially Cosmology.

With over 30,000 quasar spectra observed so far, DESI is already pushing beyond what previous spectroscopic surveys have achieved. The image shows these ~30,000 spectra stacked in different bins of redshift, with the lowest redshift bin (z<0.4) corresponding to the objects closest to us. The dashed lines indicate the main emission lines in the spectra, each of which provide important information about the nature of the object: for example, the Oxygen lines can be used to study outflows close to the supermassive black hole. The clarity of the spectra and different lines really highlights the amazing quality of the data—the two red dotted lines show galaxy absorption lines, so we can even clearly see the affect of the surrounding galaxy!

Other exotic objects such as Broad Absorption Line Quasars (BALQSOs), systems known to host powerful outflows, have also been found within DESI (see image below). The dips to the left of the CIV, SiIV and Lya line are called BAL “troughs”, which deepen with increasing “balnicity index (BI)”; a measure of the strength of the trough. Studying these systems may be really important for understanding the processes that connect AGNs and their host galaxies.

DESI also pushes to fainter and more obscured systems which have been difficult to observe with shallower spectroscopic surveys. Quasars enshrouded by dust (“red quasars”) may represent an important phase in galaxy evolution so understanding their properties is crucial – these are the objects I am most interested in!

With millions of more quasar spectra to come, the future of quasar physics looks bright. I personally look forward to analysing the data and exploring all the weird and wonderful objects DESI has to offer.

David Schlegel, DESI Project Scientist

July 22, 2021

Only eight weeks into DESI’s five-year mission, a 3-dimensional map of the universe is starting to take shape.

Plotted below is a “pie diagram” slice through the universe, with earth in the lower left, looking out in the directions of the constellations Virgo, Serpens and Hercules to distances beyond 5 billion light years. As this video progresses, the vantage point sweeps through 20 degrees towards Bootes and Corona Borealis. Each point represents a DESI target. The nearest are the bright galaxy sample (BGS as white points), then the luminous red galaxies (LRGs in red), emission line galaxies (ELGs in green), and finally quasi-stellar objects (QSOs in blue). Each of these targets is composed of 100 billion to 1 trillion stars, although we plot each target only as a single point. Gravity has clustered the galaxies into structures called the “cosmic web”, with dense clusters, filaments and voids.

DESI shuts down today for summer maintenance and upgrades, timed to coincide with the monsoon season in Arizona. When observations re-start in September, five times more galaxies will be observed at each sky location, gaps in this map will be filled in, and the area surveyed will eventually grow to span most of the sky visible from the northern hemisphere.

Ignasi Pérez i Ràfols

Santiago Serrano Elorduy

Andrea Muñoz Gutiérrez

Alma Xochitl Gonzalez Morales

Charles-Antoine Claveau

Christopher Manser

Richard Joyce

Tami Blackwell

What is your position or role in the DESI project?
I am a third year PhD student at Durham University, working on red quasars within the Galaxy Quasar Physics working group. Quasars are high redshift objects that tend to be very blue, but there is a small but important subset that show much redder colours (“red quasars”). Our group at Durham are very interested in these red quasars because we have found fundamental differences in the radio properties of red quasars, compared to their blue counterparts. We are excited to explore reddened quasars within DESI.

Where were you born?
I was born in Yorkshire in the UK, but grew up down South in in Berkshire so never got the accent!

Where do you live now?
I now live in Durham UK, close to the University. Durham is a beautiful city and I love walking by the river.

What do you as part of DESI?
Within DESI I am studying the diversity of quasars and in particular dust-reddened quasars. I have a secondary target program that has been targeting reddened quasars that may have otherwise been missed by the nominal QSO selection. I am also a member of the ECS committee within DESI. The ECS committee organises monthly ECS meetings and plans pre-meeting ECS activities such as networking events and data tutorials.

What is the most interesting or exciting thing about DESI ?
I love being connected to people within the collaboration from all over the world. I have already learnt so much from being part of DESI and have met so many interesting people. In my work I enjoy exploring new datasets, trying to make connections and understanding new results. I particularly enjoy looking at different exotic quasar systems that DESI has been observing such as broad absorption line quasars and reddened quasars.

Any advice for an aspiring scientist?
Never give up and never think you are not good enough. Sometimes you might wonder whether there is an easier path than academia, but ask yourself if there is anything as enjoyable as exploring the Universe!

What do you do for fun?
I like going to the pub with my friends—and Durham is not short on great pubs! I also enjoy giving public science talks and going to music festivals.

The DESI Legacy Imaging Surveys team is pleased to announce the public release of the Siena Galaxy Atlas 2020 (SGA-2020), a value-added supplemental catalog to imaging Data Release 9 (DR9).

The SGA-2020 is a multiwavelength atlas of 383,620 nearby galaxies selected over the 20,000 square-degree imaging footprint based on their (large) apparent angular diameter. It has been used in Survey Validation and the Main Survey to improve the selection of BGS targets, for improved masking of faint, dark-time (ELG, LRG, QSO) targets, in secondary target programs (e.g., to facilitate studies of the peculiar velocity field in the local volume via the Tully-Fisher and Faber-Jackson relations), and more. Read more about the SGA-2020 on the AAS poster.

For each galaxy in the SGA, we carry out the following measurements:

We generate custom grz and W1W2 image stacks using all the available imaging (upper-left panel);
We use The Tractor, in the context of the legacypipe photometric pipeline to build a model of all the sources in the field (middle-left panel);
We subtract all the sources in the field except the object of interest from the data and measure the surface-brightness profile using nested, fixed-geometry elliptical isophotes (bottom-left panel).

This procedure yields the non-parametric grz surface-brightness profiles, g-r and r-z color-radius profiles, and grz curves of growth shown in the right-hand panels of the figure above, and more.

Documentation of the SGA-2020 can be found here. A queryable web-application is also available here.

What is your position or role in the DESI project?
I am a graduate student at the Ohio State University working with Klaus Honscheid and Ashley Ross. I have primarily focused on DESI’s fiber positioner robots which I have a long history with stretching back to my time as an undergraduate at the University of Michigan.

Where were you born? Where do you live now?
I was born in Pontiac, Michigan on the north side of Metro Detroit. A fun fact is that the car company Pontiac (now defunct) is named after the city which in turn was named after Pontiac, a chief of the Ottawa people. I now live in Columbus, Ohio.

What do you do as part of DESI?
I have been working with DESI’s fiber positioner robots since 2016. My work has been a good mix of writing software, running hardware, and thinking a lot about how the robots move, including calibration and individual quirks. When I moved to Ohio State the scale of my work grew and I developed the software interface between the Instrument Control System and the Focal Plane System. Through the commissioning campaign I was hard at work with the rest of the focal plane team in operating the focal plane, addressing operational quirks, and improving the operational efficiency when using the focal plane.

Most recently I have become interested in the creation of the clustering catalogues from DESI data. DESI views the universe in its own unique way, creating a characteristic fingerprint in its data. When trying to extract cosmological information from DESI’s observations it is important to understand and take out effects that arise from DESI’s hardware and observing strategy. This way we can make conclusions on the underlying universe rather than just what DESI saw.

What is the most interesting or exciting thing about your job?
It is exciting to work on such an amazing instrument. DESI’s 5,000 positioner robots are a complex system to work with but they enable us to map galaxies on a scale never done before. Another great feature of DESI is that its size requires a large collaboration of vibrant people to learn from and interact with!

Any advice for an aspiring scientist?
I am still a young scientist myself but learning to ask questions is a skill that I am still developing and wish I had developed earlier. There should be no shame in not knowing something. Also asking a question can dramatically increase the value of reading a paper or listening to a talk.

What do you do for fun?
When I get the time, I love to go hiking; both on day hikes and multi-day hikes. When I do not have time, I go for walks instead. More often though I spend my time reading, enjoying some music, or experimenting in the kitchen.

What is your position or role in the DESI project?
I am a PhD student working with my supervisor Lado Samushia from Kansas state university mainly involved in Galaxy & quasar clustering working group.

Where were you born and where do you live now?
I was born in Beijing, spent my college time at Nanjing and now live in Manhattan, Kansas. Of course I feel most at home in Beijing but I am getting used to life in this peaceful and friendly small town in the Midwest.

What are the interesting places that standout that your work has taken you to?
Before starting graduate school, I got a chance to travel to Canary island, which is in the Atlantic Ocean, for a cosmology summer school. The night there is so dark and mysterious. I grew up in a big city and I have never seen such a clear but starry sky. I am looking forward to visiting Kitt Peak through a DESI related trip someday.

What would you say is the most interesting or exciting thing about your job?
As a DESI member, I have the opportunity to work with top groups from all over the world and it’s really exciting to see effort from collaboration members pushing the project forward. Personally, I enjoy extracting physics information for huge datasets. There are different ways to analyze DESI data and you can always find something new. It is interesting to gradually unveil the mystery of the universe.

Any advice for aspiring scientists?
Find your research interest, keep moving forward and learn coding.

Finally, what do you do for fun?
I used to play piano but I don’t have one here. I do photography, hiking and gaming. Dota2 will be a good topic but not League of Legends.

Aaron Meisner, NOIRLab

November 17, 2020

It’s remarkable to think that our DESI Legacy Surveys team completed on order a thousand nights of ground-based observing from Kitt Peak and Cerro Tololo. All the while in low-Earth orbit, NASA’s WISE satellite has been steadily and reliably amassing nearly a decade of full-sky data at infrared wavelengths of 3-5 microns. WISE continuously obtains a new pair of degree-sized images every ~10 seconds, observing around the clock.

Selection of DESI’s luminous red galaxy and quasar targets requires not only optical data from telescopes like the Mayall and Blanco, but also infrared fluxes from WISE. It’s therefore crucial that DESI target selection make full use of the entire WISE data set. Once each year, we download millions of recently acquired raw WISE images to NERSC and use these to update DESI’s custom, coadded WISE maps. As of DR9, the raw WISE data set assembled at NERSC has grown to a quarter petabyte in size! Each year, upon completion of our latest WISE map-making efforts, we can once again declare that DESI has created the deepest ever full-sky maps and catalogs at mid-infrared wavelengths. DR9 incorporates seven years of WISE observations, versus five years for DR8 and just one year for DR1.

WISE has scanned the entire sky more than a dozen times, lending a strong time-domain component to the Legacy Surveys data products. Our Legacy Surveys WISE light curves for ~2 billion sources represent a totally unprecedented and as-yet little explored data set. Mining DR9’s infrared data products, especially in combination with optical Legacy Surveys photometry and DESI spectroscopy, will provide a diverse array of scientific opportunities throughout the coming years.

Light echoes from a Milky Way supernova, as seen in the time-domain ‘unWISE’ coadds of Legacy Surveys DR9. These custom WISE coadds also enable DESI’s selection of faint variable quasar candidates.

The Kitt Peak National Observatory, where the Mayall telescope houses the Dark Energy Spectroscopic Instrument, was closed in March, 2020 due to the global coronavirus pandemic. The observatory cautiously and carefully reopened for maintenance in September, 2020 and since then has been slowly ramping up activities. Critical telescope maintenance and instrument improvements are being made in anticipation of a re-commissioning phase of DESI in November. Following this re-commissioning period, during which we will confirm that the instrument provides the same performance as it did pre-shutdown, we will start our Survey Validation phase. The team is excited and eager to once again start collecting data!

Matt Evatt and Patrick Dunlop practicing social distancing while preparing the Mayall telescope for on-sky DESI operations.

Adam Myers, University of Wyoming

November 4, 2020

The Dark Energy Spectroscopic Instrument will conduct spectroscopy of truly vast numbers of cosmological and astrophysical sources. These include Bright Galaxies, Emission Line Galaxies (ELGs), Luminous Red Galaxies (LRGs), Quasars, and objects in our own Milky Way Galaxy. DESI spectra are obtained by aligning optical fibers with locations on the sky, to collect light to be analyzed by dedicated spectrographs. But, how do DESI scientists know where to place those optical fibers in the first place?

Sources for the DESI key projects are targeted using images of the sky from the DESI Legacy Imaging Surveys. The Legacy Surveys include optical photometry from dedicated campaigns with the Mayall and Bok telescopes at Kitt Peak National Observatory, near Tucson, and the Blanco telescope at Cerro Tololo Inter-American Observatory near La Serena in Chile. The Legacy Surveys also incorporate infrared imaging from the WISE and NEOWISE missions, and source detections from the Gaia survey.

When envisioning the process of finding distinct objects in the sky, it is tempting to picture a bright, extended galaxy, such as this one:

Image from the Legacy Survey Viewer, using data from DR8 at right ascension of ~217.6 deg. and declination of ~11.9. See original here. credit: Legacy Surveys / D. Lang (Perimeter Institute)

But, in truth, the vast majority of DESI targets are far less spectacular to the eye, and are selected based on properties such as their color in addition to their shape. Below is the same image from the Legacy Survey Viewer above with the targets identified with circles. You’ll see that there are many more DESI targets in this field than you might have naively expected!

Same image as above from the Legacy Survey Viewer with the targets identified. You can do this yourself by selecting “DESI Targets” in the Legacy Survey Viewer menu. credit: Legacy Surveys / D. Lang (Perimeter Institute)

To determine which of the one-and-a-half-billion or so sources in the Legacy Surveys will be the lucky few tens-of-millions targeted by DESI requires sophisticated computer algorithms to sift through sources and target objects with specific photometric properties. The publicly available software that DESI uses, which is called desitarget, comprises tens-of-thousands of lines of code and has received contributions from dozens of DESI scientists.

The DESI collaboration recently released a series of research notes detailing the currently expected targeting algorithms for the DESI five-year survey:

Bright Galaxies (Ruiz-Macias et al.)
Luminous Red Galaxies (Zhou et al.)
Emission Line Galaxies (Raichoor et al.)
Quasars (Yèche et al.)
Milky Way Sources (Allende Prieto et al.)

The target catalogs that correspond to these notes, which are drawn from Data Release 8 of the DESI Legacy Imaging Surveys, are publicly available here in a format described here.

Although it is a significant milestone to have the first official DESI target catalogs in-hand, the dedicated effort of the collaboration continues. The next data release of the Legacy Surveys (Data Release 9) will soon be used to optimize, refine and finalize the target catalogs for the DESI five-year survey, during a phase of the project known as Survey Validation.

What is your position or role in the DESI project?
I am a PhD student working mainly as a part of the Target Selection and Galaxy and Quasar Physics Working Groups.

Where were you born and where do you live now?
I was born in a small town in North Eastern India called Agartala. After doing by undergraduate studies in Bhubaneswar, India, I moved to Pittsburgh, USA where I am currently doing my grad school at the University of Pittsburgh.

What do you do as part of DESI?
I mostly work on developing and testing algorithms to select objects of which DESI will measure the spectra using the data from the imaging surveys. After the observations, I also go through the spectra to check whether the data satisfies all the science requirements. I also work on studying the physics of galaxies and want to study how populations of galaxies evolve. I have also done some observations with the instrument and help in developing some of the infrastructure for the survey.

What is the most interesting or exciting thing about DESI?
Astronomy is the oldest form of observational science but we still know so little about our universe. We are still in the dark about what 95% of the universe is made of! By being a part of DESI, I get to work with a lot of wonderful people who are trying to answer some of the most basic and profound questions about our Universe like, When and Why did everything begin? or What is causing the expansion of the Universe? This exploration of the unknown is what excites me the most.

Any advice for an aspiring scientist?
Be curious, ask questions and try explore all the resources available to find the answers yourself. Sometimes you will find an answer, sometimes you won’t but in the process you will get to understand the scientific method of tackling a problem. Even if you don’t end up being a professional scientist, I believe learning the scientific method to solve any problem in our life is very important.

What do you do for fun?
I love exploring different cuisines and and recreate them on my own. I love to go out on hikes and explore new places. I also like to talk to others about science and help organize science outreach events in the city.

Joe DeRose

pfagrelius

Victoria Fawcett, Durham University

July 22, 2021

David Schlegel, DESI Project Scientist

July 22, 2021

Aaron Meisner, NOIRLab

November 17, 2020

Adam Myers, University of Wyoming

November 4, 2020

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