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blog

DESI Begins Search for Elusive Dark Energy

May 15, 2021 by almagonzalez

Paul Martini, DESI Instrument Scientist
May 17, 2021

The discovery of cosmic acceleration over twenty years ago captured the imagination of the general public and professional scientists alike, and the cause of this acceleration remains one of the greatest, unsolved questions in science. Something mysterious, such as a new particle, a new force of nature, or some property of space itself, is overcoming the gravitational attraction of all of the mass in the universe. While we commonly call the origin of this acceleration ‘dark energy,’ naming it did not solve the mystery, nor have the last two decades of progressively larger and more sophisticated sky surveys. 

Enter the DESI survey. For the last decade, hundreds of scientists and engineers have worked to build a new instrument and design a survey capable of constructing the most precise measurement of cosmic expansion history ever. On Friday, May 14 this work came to fruition with the formal launch of survey observations. And over the next five years, DESI will measure approximately 35 million galaxies and quasars that extend across about 12 billion years of cosmic history. These observations will measure an order of magnitude more targets than the largest survey to date, and complete these observations in a small fraction of the time. 

DESI aims to survey about 14,000 square degrees of the night sky, which corresponds to most of the sky visible from Arizona. We will do this with over 15,000 unique observations that we call tiles. Each of these tiles is a unique configuration of the 5000 robotically-positioned fiber optic cables designed to collect the light of specific galaxies and quasars distributed across the 3.2 degree diameter field of view of the instrument. 

The image below shows a small fraction of this field of view that includes the nearby Coma cluster of galaxies, one of the largest concentrations of galaxies in the local universe. The circles in the bottom panel illustrates the high density of the spectroscopic observations obtained with a single tile. Nearly 10,000 of these tiles are designed for good to great conditions, such as when the Moon does not appreciably affect the darkness of the night sky. In these cases, we observe our faintest targets, including luminous red galaxies, emission-line galaxies, and quasars. The remaining tiles target brighter galaxies and Milky Way stars, sources that can be observed when the moon is brighter and there may be moderate cloud cover.

A small part of the Coma cluster of galaxies (top) with redshifts from DESI added (bottom). This nearby cluster is approximately 300 million light years from Earth and is one of the largest concentrations of galaxies in the local universe. It contains many thousands of galaxies comparable to or larger than our Milky Way in size. Both the large number and high density of redshift measurements is a small sample of how efficiently DESI can measure galaxies.The area of this image is less than 1% of the field of view of DESI. (Credit: DESI collaboration and DESI Legacy Imaging Surveys)

As the DESI survey will be so much larger than previous surveys, we anticipate measuring cosmic acceleration and other parameters with substantially smaller statistical errors. Yet in order to fully realize these gains, and not be limited by systematic effects, it is especially important for us to carefully plan all aspects of the experimental design and maximize the reproducibility of our work. One aspect of this is that we have built substantial software and hardware systems to help us to achieve the same sensitivity with all of our tiles, in spite of the fact that they will be observed on nights spread over five years, and obtained under nights with varying amounts of atmospheric turbulence or seeing, and varying amounts of cloud cover. Other aspects include superb and repeatable algorithms that handle every aspect of observing, ranging from the selection of potential targets, to the assignment of targets to the individual fibers, to the measurement of their properties. 

We have spent the last many months building, testing, and refining all of these aspects of the survey with increasingly sophisticated and extensive observations. During this Survey Validation phase, we have obtained over 1 million unique redshifts, which has already made DESI the second largest spectroscopic redshift survey in the world before it formally begins. Over the coming months, we expect that the number of new galaxies and quasars we measure will continue to expand, much like the universe itself!

Filed Under: blog, feature on homepage

DESI begins its “1% Survey”

April 28, 2021 by almagonzalez

Daniel Eisenstein, Harvard University
April 28, 2021

On April 5, 2021, DESI turned to the second and final phase of its Survey Validation (SV) work, the so-called “1% survey”.  Whereas the first phase of SV was aimed at getting long and definitive observations of a broad superset of the planned spectroscopic targets, the 1% survey aims to demonstrate that we can operate the facility in a model closely matched to that planned for the 5-year survey.

The 1% survey is being conducted with target selection similar to what is planned for the main survey and with exposure times only mildly longer.  Importantly, we aim to observe each region of sky more times than in the main survey so that we achieve a higher fiber-assignment completeness, the fraction of targets that are assigned a fiber.

A single exposure with DESI provides about 600 fibers per square degree, but the survey target lists contain about 3500 targets per square degree for the dark/grey conditions (when the moon is small or set) and about 2000-2500 targets per square degree for bright conditions (when the moon is fuller).  In the main survey, we will return to a point on the sky numerous times to observe about 80% of the targets, but allowing some incompleteness so that we can efficiently move on to new regions.  In the 1% survey, we plan to return to each region at least 10 times for dark-time targets and 8 times for bright-time targets, each with a distinct target list, so as to observe all but a few percent of the targets.

So far, we have started observations on 16 regions, each 7 square degrees and each including both dark-time and bright-time targets.  We expect to finish this program in May.  With this data set, we will be able to get a first estimate of the 3-dimensional clustering of the galaxy and quasar samples, which will then allow the collaboration to tune the models of simulated galaxy positions in our cosmological mock catalog.

With the observations moving at normal survey pace from one target set to the next, the rate of gathering new redshifts has increased dramatically.  In the first 8 nights, we acquired over 400,000 separate successful redshift measurements of 350,000 unique sources.

DESI Collaboration. Daniel Eisenstein (Harvard University)

The plot shows a visualization of one of the 16 regions, which has 13 dark-time visits, showing a map of the galaxy locations in Mpc on the plane of the sky.  Only galaxies between redshift 0.90 and 0.95 are shown, with the luminous red galaxy targets plotted in red and the emission-line galaxy targets in blue.  One can see the cosmic web of large-scale structure, with walls, filaments, and voids, as well as the tendency of red galaxies to cluster together more than blue galaxies.  This is about 1 part in 20,000 of the final survey size!

Filed Under: blog, feature on homepage

DESI Embarks on Survey Validation

April 19, 2021 by almagonzalez

Daniel Eisenstein, Harvard University
April 19, 2021

Since mid-December, DESI has been intensively performing its Survey Validation (SV) observations. With SV, we seek to optimize the 5-year survey design using on-sky observations of our target classes. We of course based our designs on what was known before DESI, but DESI is a big enough step forward that one can’t be sure until one verifies the performance with the instrument itself!

One of the challenges for Survey Validation is that we want to verify our survey plans with targets that are fainter and spread over wider areas of the sky than have previously been observed. So we need to make our own truth tables by observing our targets with much longer exposures than we plan for the survey, so that the correct answers become obvious. We then can split the observations into portions to see what a survey-length exposure would yield. 

A small region from the Dark Energy Camera Legacy Survey (DECaLS), roughly 0.1 degree across, overlaid with redshifts from DESI survey validation spectroscopy. Visible here are representatives from DESI’s major extragalactic targets: two quasars (QSO) beyond redshift 2; luminous red galaxies at redshift 0.8; an emission-line galaxy at redshift 1.1, fainter than r-band magnitude 23; and two brighter galaxies at lower redshift. The grey circle marks the location of a fiber placed on a blank position to monitor the emission from the sky.

From mid-December through the end of March, DESI observed 161 separate tiles as part of the first phase of its survey validation program, collecting over 1600 separate spectroscopic exposures. We combined 4.3 million separate observations of 465,000 distinct examples of our target classes, with an average of 95 minutes per target, obtaining redshifts for 412,000 objects. This is already one of the largest extragalactic spectroscopic data sets ever collected, including 108,000 redshifts above 0.8.

The whole DESI collaboration has mobilized to analyze these on-sky data, because rapid answers are needed to define the main survey. The results have been very encouraging; we’ll share more examples in future blog posts.

Filed Under: blog, feature on homepage

An Undergrad Perspective on DESI

April 15, 2021 by almagonzalez

Brian Bauer, Daniel Allspach, and Noah Franz
April 16, 2021

We are a working group of three undergraduate students at Siena College. We started with DESI under Dr. John Moustakas in February 2020. We were intrigued by the opportunity to work with such a large collaboration with so many scientific possibilities. Since then, Noah Franz and Brian Bauer have focused on identifying strong gravitational lenses in DESI spectra by using Python to separate the source and lens galaxy spectra then analyzing the success. Daniel Allspach has been working to fit stellar templates to model DESI spectra continua and determine galactic demographics and outflow classifications. Contributing to these projects has provided us with invaluable insight and experience into working with large collaborations.

Left to right: Noah Franz, Brian Bauer, Daniel Allspach

After working with DESI, attending Zoom telecons, and learning how a collaboration functions, what we enjoyed most of all is the welcoming nature of everyone involved. Without this feeling of acceptance we would have found it difficult to integrate into a project effectively. Although receiving emails in the wee hours of the morning can be a little odd at first, we were able to quickly adapt and become accustomed to the practices and methods employed by DESI. Being included in any aspect of the project, especially as an undergraduate, is an honor, yet we were continually challenged to dive deeper and join as much as we can. A welcoming environment provides the perfect jumping off point for new members and that is truly the best part about the DESI collaboration.

With over 700 contributing members, DESI is a large collaboration, and, as undergraduate researchers we found entering the community of mostly graduate students and PhDs intimidating and overwhelming. While some of the DESI updates and zoom meetings can be daunting, after spending time reading the literature and learning the acronyms we became accustomed to the jargon. Once we surpassed this learning curve, we were able to start our own research projects. In many ways this was our introduction into large scale collaborative astronomy and cosmology: many things are new to us. Having the DESI environment to help us orient and navigate this research environment has been incredibly helpful. DESI has given us a fantastic first experience not just with research but also working with a large collaboration. As a result, we all were inspired to continue research going into the future.

Filed Under: blog, feature on homepage

Women in DESI on International Women’s Day

March 9, 2021 by almagonzalez

Education and Public Outreach group collaborators (Shanthala Gorur, Michael Wilson, Alma González, and many others)
March 8, 2021

To commemorate the 2021 International day of Women, March 8th, we wanted to highlight and show the work of the many women working in DESI.

We asked the women in DESI to share with us their advise for the new generations to come, and the work they are doing in DESI.

We start this post with a collage from the pictures and a small selection of the responses.

This post will continue with some more of the particular responses, on twitter, stay tuned.

SPANISH VERSION

Filed Under: blog, feature on homepage

Hunting the Oxygen Doublet in Distant Galaxies

February 3, 2021 by almagonzalez

John Moustakas, Siena College
February  3, 2021

In its quest to uncover the mysteries of dark energy, DESI will measure precise redshifts for more than 15 million emission-line galaxies or “ELGs.” Although they are incredibly distant and faint, DESI will take advantage of a distinctive feature in the light emitted by these galaxies—a feature called the “oxygen two doublet”, represented by the symbol “[OII]”.

But what is this so-called doublet and where does it come from? And why oxygen? To answer these questions we need to dig into some astrophysics!

Did you know that after hydrogen and helium, oxygen is by far the most abundant element in the universe? For example, in our solar system there are one-and-a-half times more oxygen atoms than carbon atoms and nearly twenty times more oxygen atoms than iron atoms! Because it is so common, oxygen is also an incredibly important element in galaxies, especially in the gas between stars, what astronomers call the “interstellar medium.” In fact, oxygen is one of the primary ways for galaxies to “cool down.”

Let’s take a quick look at what this means. In galaxies, new stars generally form at the centers of cold, dense clouds of gas and dust. Occasionally, a very massive star will be born—a hot, bright star which can be anywhere from two to one hundred times more massive than the Sun. These monster stars pump enormous amounts of high-energy photons (i.e., light) into the surrounding gas, stripping away the electrons which are normally bound to atoms and creating a spectacular “soup” of fast-moving electrons, protons, and positively charged heavier atoms like oxygen surrounding the new star. Astronomers call these vibrant, short-lived sites of activity in galaxies “HII regions” or “star-forming regions”.

30 Doradus Across the Spectrum (Credit: Q. Daniel Wang (NWU), UM/CTIO, UIT, ROSAT.)

Now, the typical temperature of these star-forming regions is a balmy 10,000 degrees Kelvin, hotter than the surface of the Sun! So how does the region get rid of this extra energy and cool down? Well, as atoms like oxygen whip around in random directions, they will occasionally crash into one another. When this happens, some of the kinetic energy of motion goes into “exciting” one of the atom’s electrons into a higher energy state. But the electron doesn’t stay excited very long!

After about a second, the excited electron spontaneously “jumps down” to a lower energy level, simultaneously emitting a photon of energy (i.e., light) in the process. Subsequently, this photon escapes from the star-forming region, robbing it of the original energy pumped in by the hot young star and helping it cool down. In the actively star-forming emission-line galaxies which DESI is hunting, we observe oxygen “shining” in this way at two close but distinct energies or wavelengths, 372.71 and 372.98 nanometers. (One nanometer is one billionth of a meter, so the wavelength of this light is about 170 times smaller than the width of human hair!)

This pair of lines is called the “oxygen two doublet” (the “two” confusingly means that the oxygen atom is missing one electron) and it is written using the symbol “[O II].” In December 2020, DESI began observations as part of its “Survey Validation” phase, and one important question this phase aims to answer is, “How efficiently will DESI be able to pre-select (or “target”) emission-line galaxies?” So far, the answer to this question has been a resounding, “Really well!” To illustrate the kind of tremendous data DESI is obtaining, Dr. Julien Guy of Lawrence Berkeley National Lab has created an animation of the [OII] doublet in a sample of roughly 3400 emission-line galaxies which DESI observed in December, a tiny fraction of the more than 35 million galaxies DESI will observe during its 5-year survey.

credit: DESI Collaboration

This movie shows the strikingly clear [OII] doublet in these galaxies, which brings DESI one step closer to being able to uncover the mystery of dark energy.

Filed Under: blog, feature on homepage

Congratulations to David Weinberg

January 19, 2021 by almagonzalez

Jeremy Tinker and Zheng Zheng
January 19, 2021

DESI member and noted rapper David Weinberg, from Ohio State University, was awarded the Dannie Heineman Prize for Astrophysics. He shares the award with Robert Lupton of Princeton University. The award celebrates the massive contributions both researchers have made to ushering in the era of large-scale three-dimensional mapping of the universe through the spatial distribution of the galaxies within it, primarily through their work with the Sloan Digital Sky Survey (SDSS).

As a project, DESI owes a debt of gratitude to SDSS. SDSS was the first truly large-scale galaxy redshift survey, using a CCD camera and fiber-fed spectrographs. With first light in 2000, its goal— realized in 2007 with the completion of SDSS-II— was to map nearly a quarter of sky by obtaining distances (redshifts) of the million brightest galaxies and quasars in the universe. In late 1980s, when the SDSS was merely an idea being batted around the Paris Conference Room of the Chicago O’Hare Hilton, David was a graduate student at Princeton, working with SDSS’s visionary founder Jim Gunn. He both literally and figuratively got started on the ground floor of large-scale spectroscopic surveys.

From left to right: (a) An image of the gas distribution around a nascent galaxy forming in a supercomputer simulation, taken from the paper “How Do Galaxies Get Their Gas?” (b) The map of the Main Galaxy Survey of the SDSS, color-coded by the stellar age of each galaxy (image created by Mike Blanton). (c) The Last Scattering Surface, by Josiah McElheny, with scientific consulting by David Weinberg.

David became a full SDSS member in 1992, and went on to serve as the Scientific Spokesperson for SDSS-II, a position that demands a myriad of critical tasks related to the design, organization, promotion, and execution of the project. When the SDSS-III collaboration was created in 2008, David was chosen to be the Project Scientist. In recent years David has brought his expertise to the DESI collaboration, being one of the chief architects of the Bright Galaxy Survey component of the project as well as serving as the inaugural BGS working group co-chair. 

While a member of SDSS, David made invaluable contributions to survey design, galaxy target selection, and eventual analysis of the maps of cosmic structure. David was an early adopter and developer of the halo occupation model to describe the distribution of galaxies in space, who introduced the now commonly used term Halo Occupation Distribution (HOD). The model relates galaxies to clumps (halos) in the matter distribution in the universe. The SDSS data led to the pioneering application of the HOD framework to interpret the clustering of galaxies in space, with clustering trend naturally explained and galaxy-halo connection informatively inferred. The HOD model has ever since been widely adopted to analyze galaxy clustering data, becoming a powerful tool in learning about galaxy formation and cosmology and in creating simulated galaxy catalogs for various purposes in large galaxy surveys. 

In addition to mapping the universe with galaxies, David was also a pioneer in a novel method of determining the matter distribution of the universe: the Lyman-alpha forest. This method uses bright quasars as cosmological flashlights. Cool gas along the pathway to our telescopes absorbs some of the quasars’ light, leaving wiggles (Lyman-alpha forest) in the quasar spectra. Such wiggles reveal the spatial distribution of cool gas, which tracks dark matter. Thus, the spectra of quasars taken in SDSS and in DESI provide complementary maps of cosmic structure. 

As a scientist, David wears many hats in addition to survey astronomy. He has produced highly influential work on hydrodynamical simulations of galaxy formation, he has worked on the life cycles of active galactic nuclei, and more recently he has used SDSS’s spectra of stars to perform “chemical cartography” within our own Milky Way Galaxy. His 169-page review article on “Observational Probes of Cosmic Acceleration”, with nearly 900 citations, has become the standard reference in guiding our observational efforts toward revealing the nature of cosmic acceleration.

In addition to his research-oriented scientific pursuits, David has a long-standing collaboration with the MacArthur Award winning sculptor Josiah McElheny. Together, they have created cosmologically-inspired glass sculptures that have been exhibited all over the world. David’s role is in making the designs representative of the physics of the universe. For example, the piece An End to Modernity depicts the history of the universe from the Big Bang to the present day, emphasizing the evolution of cosmic structure and the epoch of galaxy formation.

Since starting at Ohio State in 1995, David has been advisor and mentor to 17 graduate students. Many of his former students, including the two of us, are themselves members of SDSS and DESI, and are using these data to mentor and train their own students, drawing on the lessons learned while working with David. Needless to say, David’s profound influence on cosmological redshift surveys will be felt for many academic generations. Congratulations to David for this well-deserved recognition of his continuing impact on astronomy, cosmology, and its presentation to the public.

Filed Under: blog, feature on homepage

DESI Imaging Leaves a Legacy at Infrared Wavelengths

November 17, 2020 by pfagrelius

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.

Filed Under: blog

DESI Target Selection

November 4, 2020 by pfagrelius

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.

Filed Under: blog

DESI Successfully Completes Commissioning Phase

April 2, 2020 by pfagrelius

Daniel Eisenstein, Harvard University
April 2, 2020

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.

Filed Under: blog

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Primary Sidebar

  • Sneaking around with DESI data
  • Lightning and a lunar eclipse over Kitt Peak
  • Untangling the Cosmic Web
  • Recovery effort update two months after the Contreras Fire
  • First batch of Year 1 Key Project 1 papers
  • Contreras Fire Threatens DESI and Kitt Peak National Observatory
  • One Year and 12.8 Million Galaxy Redshifts
  • DESI on a T-shirt (and stickers of course!)
  • Selecting Targets for the DESI Survey
  • The Old is New Again: Social Distancing While Mapping the Universe
  • Congratulations to Frank Valdes
  • The DESI peculiar velocity survey
  • DESI Breaking Records
  • A DIY Guide for Upgrading Your 100 Million Dollar World Class Astronomical Instrument
  • An Upgraded DESI Returns to the Sky
  • Cosmic Cartography
  • Diversity of DESI SV Quasars
  • The Beginnings of the 3-Dimensional Map
  • What do DESI’s 5000 eyes see?
  • Plugging Away
  • DESI Begins Search for Elusive Dark Energy
  • DESI begins its “1% Survey”
  • DESI Embarks on Survey Validation
  • An Undergrad Perspective on DESI
  • Women in DESI on International Women’s Day
  • Hunting the Oxygen Doublet in Distant Galaxies
  • Congratulations to David Weinberg
  • DESI Imaging Leaves a Legacy at Infrared Wavelengths
  • DESI Target Selection
  • DESI Successfully Completes Commissioning Phase

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