View source for Dark Energy Survey

{{Short description|Project to measure the expansion of the universe}}
{{Infobox astronomical survey}}
{{cosmology}}

The '''Dark Energy Survey''' ('''DES''') is an [[astronomical survey]] designed to constrain the properties of [[dark energy]]. It uses images taken in the near-[[ultraviolet]], [[Visible spectrum|visible]], and near-[[infrared]] to measure the [[expansion of the universe]] using [[Type Ia supernova]]e, [[baryon acoustic oscillations]], the number of [[Galaxy groups and clusters|galaxy clusters]], and [[weak gravitational lensing]].<ref>{{Cite web|url=https://www.darkenergysurvey.org/|title=Home|website=The Dark Energy Survey}}</ref> The collaboration is composed of research institutions and universities from the United States,<ref name="deshp">[http://www.darkenergysurvey.org/collaboration/ DES Collaboration Page], DES Collaborators.</ref> Australia, Brazil,<ref name="desbrazil">[http://des-brazil.linea.gov.br// DES-Brazil] {{webarchive|url=https://web.archive.org/web/20141022043124/http://des-brazil.linea.gov.br/ |date=2014-10-22 }}, DES-Brazil Consortium.</ref> the United Kingdom, Germany, Spain, and Switzerland. The collaboration is divided into several scientific working groups. The director of DES is [[Joshua A. Frieman|Josh Frieman]].<ref>{{Cite web|title = The Dark Energy Survey Collaboration|url = http://www.darkenergysurvey.org/collaboration/|website = www.darkenergysurvey.org|access-date = 2015-11-21}}</ref>

The DES began by developing and building [[#DECam|Dark Energy Camera]] (DECam), an instrument designed specifically for the survey.<ref name="des_data_wb">[https://des.fnal.gov/ The Project - The Dark Energy Survey Collaboration], The DES Project Site.</ref> This camera has a wide field of view and high sensitivity, particularly in the red part of the [[visible spectrum]] and in the near infrared.<ref name="dec_cam"/> Observations were performed with DECam mounted on the 4-meter [[Víctor M. Blanco Telescope]], located at the [[Cerro Tololo Inter-American Observatory]] (CTIO) in Chile.<ref name="dec_cam">[http://www.ctio.noao.edu/noao/content/dark-energy-camera-decam/ Dark Energy Camera (DECam)] {{Webarchive|url=https://web.archive.org/web/20190523084014/http://www.ctio.noao.edu/noao/content/dark-energy-camera-decam |date=2019-05-23 }}, ''Cerro Tololo Inter-American Observatory''.</ref> Observing sessions ran from 2013 to 2019; {{as of|2021|lc=y}} the DES collaboration has published results from the first three years of the survey.<ref>{{cite web |title=DES Year 3 Cosmology Results: Papers |url=https://www.darkenergysurvey.org/des-year-3-cosmology-results-papers/ |website=The Dark Energy Survey |access-date=3 August 2021}}</ref>

== DECam ==
[[File:A_Sky_Full_of_Galaxies.jpg|thumb|A sky full of galaxies<ref>{{cite web |title=A Sky Full of Galaxies |url=https://noirlab.edu/public/images/iotw2110a/ |website=[[NOIRLab]] |access-date=12 March 2021 |language=en}}</ref>]]

'''DECam''', short for the '''Dark Energy Camera''', is a large camera built to replace the previous prime focus camera on the Victor M. Blanco Telescope. The camera consists of three major components: mechanics, optics, and [[Charge-coupled device|CCDs]].

=== Mechanics ===

The mechanics of the camera consists of a filter changer with an 8-filter capacity and shutter. There is also an optical barrel that supports 5 corrector lenses, the largest of which is 98&nbsp;cm in diameter. These components are attached to the CCD focal plane which is cooled to {{convert|173|K|F C}} with [[liquid nitrogen]] in order to reduce thermal noise in the CCDs. The focal plane is also kept in an extremely low vacuum of {{convert|0.00013|Pa|atm}} to prevent the formation of condensation on the sensors. The entire camera with lenses, filters, and CCDs weighs approximately 4 tons. When mounted at the prime focus it was supported with a [[Stewart platform|hexapod]] system allowing for real time focal adjustment.<ref name="dec_cam_explanation"/>

=== Optics ===

The camera is outfitted with u, g, r, i, z, and Y filters spanning roughly from 340–1070&nbsp;nm,<ref name="sdss_filters">{{Cite web|url=http://www.sdss.org/instruments/camera/#Filters|title=Camera {{pipe}} SDSS}}</ref> similar to those used in the [[Sloan Digital Sky Survey|Sloan Digital Sky Survey (SDSS)]]. This allows DES to obtain [[photometric redshift]] measurements to z≈1. DECam also contains five lenses acting as corrector optics to extend the telescope's field of view to a diameter of 2.2°, one of the widest fields of view available for ground-based optical and infrared imaging.<ref name="dec_cam"/> One significant difference between previous [[charge-coupled device]]s (CCD) at the Victor M. Blanco Telescope and DECam is the improved [[quantum efficiency]] in the red and near-infrared wavelengths.<ref name="Flaugher12">{{Cite book|chapter-url=https://www.spiedigitallibrary.org/conference-proceedings-of-spie/8446/844611/Status-of-the-Dark-Energy-Survey-Camera-DECam-project/10.1117/12.926216.short|chapter=Status of the Dark Energy Survey Camera (DECam) project|first1=Brenna L.|last1=Flaugher|editor1-first=Ian S|editor1-last=McLean|editor2-first=Suzanne K|editor2-last=Ramsay|editor3-first=Hideki|editor3-last=Takami|title=Ground-based and Airborne Instrumentation for Astronomy IV|display-authors=etal|date=September 24, 2012|publisher=International Society for Optics and Photonics|volume=8446|pages=343–357|via=www.spiedigitallibrary.org|doi=10.1117/12.926216|s2cid=121613505|url=https://digital.library.unt.edu/ark:/67531/metadc838330/}}</ref><ref name="dec_cam_explanation">[http://astro.uchicago.edu/~frieman/Courses/A411/Lecture5/Estrada-CCDs.pdf DECam Presentation] {{webarchive|url=https://web.archive.org/web/20110927014806/http://astro.uchicago.edu/~frieman/Courses/A411/Lecture5/Estrada-CCDs.pdf |date=2011-09-27 }}, Pdf Presentation about the specific details about how a CCD device works and about the specific properties of the DECam, made by a Fermilab specialist.</ref>

=== CCDs ===
[[File:Dark Energy Camera's 1 millionth exposure.jpg|thumb|The Dark Energy Camera's 1 millionth exposure. The 1 millionth exposure has been combined with 127 earlier exposures to make this view of the field.]]

The scientific [[sensor array]] on DECam is an array of 62 2048×4096 pixel [[Back-illuminated sensor|back-illuminated]] CCDs totaling 520 megapixels; an additional 12 2048×2048 pixel CCDs (50 Mpx) are used for guiding the telescope, monitoring focus, and alignment. The full DECam focal plane contains 570 megapixels. The CCDs for DECam use high resistivity silicon manufactured by [[Dalsa]] and [[Lawrence Berkeley National Laboratory|LBNL]] with 15×15 micron pixels. By comparison, the [[OmniVision Technologies]] back-illuminated CCD that was used in the [[iPhone 4]] has a 1.75×1.75 micron pixel with 5 megapixels. The larger pixels allow DECam to collect more light per pixel, improving low light sensitivity which is desirable for an astronomical instrument. DECam's CCDs also have a 250-micron crystal depth; this is significantly larger than most consumer CCDs. The additional crystal depth increases the path length travelled by entering photons. This, in turn, increases the probability of [[Photoelectric Effect|interaction]] and allows the CCDs to have an increased sensitivity to lower energy photons, extending the wavelength range to 1050&nbsp;nm. Scientifically this is important because it allows one to look for objects at a higher redshift, increasing statistical power in the studies mentioned above. When placed in the telescope's focal plane each pixel has a width of 0.27{{pprime}} on the sky, resulting in a total field of view of 3 square degrees.<ref>{{Cite web |title=The Camera |url=https://www.darkenergysurvey.org/the-des-project/instrument/the-camera/ |access-date=2024-05-02 |website=The Dark Energy Survey |language=en-US}}</ref>

== Survey ==
DES imaged 5,000 square degrees of the southern sky in a footprint that overlaps with the [[South Pole Telescope]] and [[Stripe 82]] (in large part avoiding the Milky Way). The survey took 758 observing nights spread over six annual sessions between August and February to complete, covering the survey footprint ten times in five [[photometric system|photometric bands]] (''g'', ''r, i, z'', and ''Y'').<ref name="legacy">{{cite web |title=NOAO: A Survey Machine and a Data Trove – Dark Energy Survey's Rich Legacy {{!}} CTIO |url=http://www.ctio.noao.edu/noao/content/NOAO-Survey-Machine-and-Data-Trove-%E2%80%93-Dark-Energy-Survey%E2%80%99s-Rich-Legacy |website=www.ctio.noao.edu |access-date=3 August 2021 |archive-date=22 September 2021 |archive-url=https://web.archive.org/web/20210922004415/http://www.ctio.noao.edu/noao/content/NOAO-Survey-Machine-and-Data-Trove-%E2%80%93-Dark-Energy-Survey%E2%80%99s-Rich-Legacy |url-status=dead }}</ref> The survey reached a depth of 24th [[Apparent magnitude|magnitude]] in the i band over the entire survey area. Longer exposure times and faster observing cadence were made in five smaller patches totaling 30 square degrees to search for supernovae.<ref>{{cite web|author=Dark Energy Survey Collaboration|title=Description of the Dark Energy Survey for Astronomers|url=https://www.darkenergysurvey.org/survey/des-description.pdf|website=The Dark Energy Survey|access-date=1 March 2015}}</ref>

First light was achieved on 12 September 2012;<ref>{{cite news|agency=BBC|url=https://www.bbc.co.uk/news/science-environment-19634700|title=Dark energy camera snaps first images ahead of survey|date=2012-09-18}}</ref> after a verification and testing period, scientific survey observations started in August 2013.<ref>{{cite news|agency=Fermilab|url=http://www.symmetrymagazine.org/article/september-2013/the-dark-energy-survey-begins|title=The Dark Energy Survey begins|date=2013-09-03}}</ref> The last observing session was completed on 9 January 2019.<ref name="legacy" />

=== Other surveys using DECam ===
After completion of the Dark Energy Survey, the Dark Energy Camera was used for other sky surveys:

* [[Dark Energy Camera Legacy Survey]] (DECaLS) covers the sky below 32°[[Declination]], not including the Milky Way. This survey covers over 9000 square degrees.<ref>{{Cite web |last=Survey |first=Legacy |date=2012-11-08 |title=The Dark Energy Camera Legacy Survey (DECaLS) |url=https://www.legacysurvey.org/decamls/ |access-date=2023-12-31 |website=Legacy Survey |language=en}}</ref><ref name=":2">{{Cite journal |last1=Dey |first1=Arjun |last2=Schlegel |first2=David J. |last3=Lang |first3=Dustin |last4=Blum |first4=Robert |last5=Burleigh |first5=Kaylan |last6=Fan |first6=Xiaohui |last7=Findlay |first7=Joseph R. |last8=Finkbeiner |first8=Doug |last9=Herrera |first9=David |last10=Juneau |first10=Stéphanie |last11=Landriau |first11=Martin |last12=Levi |first12=Michael |last13=McGreer |first13=Ian |last14=Meisner |first14=Aaron |last15=Myers |first15=Adam D. |date=2019-05-01 |title=Overview of the DESI Legacy Imaging Surveys |journal=The Astronomical Journal |volume=157 |issue=5 |pages=168 |doi=10.3847/1538-3881/ab089d |doi-access=free |arxiv=1804.08657 |bibcode=2019AJ....157..168D |issn=0004-6256}}</ref>
* The [[DESI Legacy Imaging Surveys]] (Legacy Surveys), as of data release 10, includes DECaLS, BASS and MzLS. It also  incorporating additional DECam data, which means that it covers almost the entire [[Extragalactic astronomy|extragalactic]] southern sky, including parts of the [[Magellanic Clouds]]. The purpose of the Legacy Surveys is to find targets for the [[Dark Energy Spectroscopic Instrument]].<ref name=":2" /><ref>{{Cite web |last=Survey |first=Legacy |date=2023-09-28 |title=Data Release Description |url=https://www.legacysurvey.org/dr10/description/ |access-date=2023-12-31 |website=Legacy Survey |language=en}}</ref>
* [[Dark Energy Camera Plane Survey]] (DECaPS), covers the [[Milky Way]] in the southern sky.<ref>{{Cite journal |last1=Schlafly |first1=E. F. |last2=Green |first2=G. M. |last3=Lang |first3=D. |last4=Daylan |first4=T. |last5=Finkbeiner |first5=D. P. |last6=Lee |first6=A. |last7=Meisner |first7=A. M. |last8=Schlegel |first8=D. |last9=Valdes |first9=F. |date=2018-02-01 |title=The DECam Plane Survey: Optical Photometry of Two Billion Objects in the Southern Galactic Plane |journal=The Astrophysical Journal Supplement Series |volume=234 |issue=2 |pages=39 |doi=10.3847/1538-4365/aaa3e2 |doi-access=free |arxiv=1710.01309 |bibcode=2018ApJS..234...39S |issn=0067-0049}}</ref>

[[File:DECam iphone insert.PNG|thumb|Simulated image of the DECam CCD array at focal plane. Each large rectangle is a single CCD. The green rectangle circled in red in the upper left corner shows the size of the [[iPhone 4]] camera CCD at the same scale.|left]]
== Observing ==
[[File:DES Observing Footprint.png|thumb|The footprint of the wide-area survey on the sky (colored region) in celestial coordinates; the dashed curve shows the approximate location of the Milky Way disk in these coordinates.]]
Each year from August through February, observers will stay in dormitories on the mountain. During a weeklong period of work, observers sleep during the day and use the telescope and camera at night. There will be some DES members working at the telescope console to monitor operations while others are monitoring camera operations and data process.

For the wide-area footprint observations, DES takes roughly every two minutes for each new image: The exposures are typically 90&nbsp;seconds long, with another 30&nbsp;seconds for readout of the camera data and slewing to point the telescope at its next target. Despite the restrictions on each exposure, the team also need to consider different sky conditions for the observations, such as moonlight and cloud cover.

In order to get better images, DES team use a [[computer algorithm]] called the "Observing Tactician" (ObsTac) to help with sequencing observations. It optimizes among different factors, such as the date and time, weather conditions, and the position of the moon. ObsTac automatically points the telescope in the best direction, and selects the exposure, using the best light filter. It also decides whether to take a wide-area or time-domain survey image, depending on whether or not the exposure will also be used for supernova searches.<ref>{{cite web |title=Observations |series=Survey and operations |website=The Dark Energy Survey |url=https://www.darkenergysurvey.org/the-des-project/survey-and-operations/}}</ref>

==Results==

=== Cosmology ===
[[File:DES clumpiness of the matter distribution.png|thumb|Constraints on a measure of the clumpiness of the matter distribution (S8) and the fractional density of the Universe in matter (Ωm) from the combined 3 DES Y1 measurements (blue), Planck CMB measurements (green), and their combination (red).]]
Dark Energy Group published several papers presenting their results for [[cosmology]].  Most of these cosmology results coming from its first-year data and the third-year data.  Their results for cosmology were concluded with a Multi-Probe Methodology, which mainly combine the data from Galaxy-Galaxy Lensing, different shape of [[weak lensing]], cosmic shear, galaxy clustering and photometric data set.

For the first-year data collected by DES, Dark Energy Survey Group showed the Cosmological Constraints results from Galaxy Clustering and Weak Lensing results and cosmic shear measurement. With Galaxy Clustering and Weak Lensing results, <math>S_8=\sigma_8(\Omega_m/0.3)^{0.5}= 0.773_{-0.020}^{+0.026}</math> and <math>\Omega_m= 0.267_{-0.017}^{+0.030}</math> for [[ΛCDM]], <math>S_8= 0.782_{-0.024}^{+0.036}</math>, <math>\Omega_m= 0.284_{-0.030}^{+0.033}</math> and <math>\omega= -0.82_{-0.20}^{+0.21}</math> at 68% confidence limits for ωCMD.<ref>{{Cite journal |last1=DES Collaboration |last2=Abbott |first2=T. M. C. |last3=Abdalla |first3=F. B. |last4=Alarcon |first4=A. |last5=Aleksić |first5=J. |last6=Allam |first6=S. |last7=Allen |first7=S. |last8=Amara |first8=A. |last9=Annis |first9=J. |last10=Asorey |first10=J. |last11=Avila |first11=S. |date=2018-08-27 |title=Dark Energy Survey Year 1 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing |journal=Physical Review D |volume=98 |issue=4 |pages=043526 |doi=10.1103/PhysRevD.98.043526 |arxiv=1708.01530 |bibcode=2018PhRvD..98d3526A |s2cid=52219057 |issn=2470-0010}}</ref> Combine the most significant measurements of cosmic shear in a galaxy survey, Dark Energy Survey Group showed that <math>\sigma_8(\Omega_m/0.3)^{0.5}= 0.782_{-0.027}^{+0.027}</math> at 68% confidence limits and <math>\sigma_8(\Omega_m/0.3)^{0.5}= 0.777_{-0.038}^{+0.036}</math> for ΛCDM with <math>\omega= -0.95_{-0.36}^{+0.33}</math>.<ref>{{Cite journal |last1=Troxel |first1=M. A. |last2=MacCrann |first2=N. |last3=Zuntz |first3=J. |last4=Eifler |first4=T. F. |last5=Krause |first5=E. |last6=Dodelson |first6=S. |last7=Gruen |first7=D. |last8=Blazek |first8=J. |last9=Friedrich |first9=O. |last10=Samuroff |first10=S. |last11=Prat |first11=J. |date=2018-08-27 |title=Dark Energy Survey Year 1 Results: Cosmological Constraints from Cosmic Shear |journal=Physical Review D |volume=98 |issue=4 |pages=043528 |doi=10.1103/PhysRevD.98.043528 |arxiv=1708.01538 |bibcode=2018PhRvD..98d3528T |s2cid=52993521 |issn=2470-0010}}</ref> Other cosmological analyses from first year data showed a derivation and validation of redshift distribution estimates and their uncertainties for the galaxies used as weak lensing sources.<ref>{{Cite journal |last1=Hoyle |first1=B. |last2=Gruen |first2=D. |last3=Bernstein |first3=G. M. |last4=Rau |first4=M. M. |last5=De Vicente |first5=J. |last6=Hartley |first6=W. G. |last7=Gaztanaga |first7=E. |last8=DeRose |first8=J. |last9=Troxel |first9=M. A. |last10=Davis |first10=C. |last11=Alarcon |first11=A. |date=2018-07-21 |title=Dark Energy Survey Year 1 Results: Redshift distributions of the weak lensing source galaxies |journal=Monthly Notices of the Royal Astronomical Society |volume=478 |issue=1 |pages=592–610 |doi=10.1093/mnras/sty957 |doi-access=free |arxiv=1708.01532 |issn=0035-8711}}</ref> The DES team also published a paper summarize all the Photometric Data Set for Cosmology for their first-year data.<ref>{{Cite journal |last1=Drlica-Wagner |first1=A. |last2=Sevilla-Noarbe |first2=I. |last3=Rykoff |first3=E. S. |last4=Gruendl |first4=R. A. |last5=Yanny |first5=B. |last6=Tucker |first6=D. L. |last7=Hoyle |first7=B. |last8=Rosell |first8=A. Carnero |last9=Bernstein |first9=G. M. |last10=Bechtol |first10=K. |last11=Becker |first11=M. R. |date=2018-04-03 |title=Dark Energy Survey Year 1 Results: Photometric Data Set for Cosmology |journal=The Astrophysical Journal Supplement Series |volume=235 |issue=2 |pages=33 |doi=10.3847/1538-4365/aab4f5 |arxiv=1708.01531 |bibcode=2018ApJS..235...33D |s2cid=53967977 |issn=1538-4365 |doi-access=free }}</ref>

For the third-year data collected by DES, they updated the Cosmological Constraints to <math>\sigma_8(\Omega_m/0.3)^{0.5}= 0.759_{-0.025}^{+0.023}</math> for the ΛCDM model with the new cosmic shear measurements.<ref>{{Cite journal |last1=Porredon |first1=A. |last2=Crocce |first2=M. |last3=Elvin-Poole |first3=J. |last4=Cawthon |first4=R. |last5=Giannini |first5=G. |last6=De Vicente |first6=J. |last7=Rosell |first7=A. Carnero |last8=Ferrero |first8=I. |last9=Krause |first9=E. |last10=Fang |first10=X. |last11=Prat |first11=J. |year=2022 |title=Dark Energy Survey Year 3 results: Cosmological constraints from galaxy clustering and galaxy-galaxy lensing using the MagLim lens sample |journal=Physical Review D |volume=106 |issue=10 |page=103530 |arxiv=2105.13546 |doi=10.1103/PhysRevD.106.103530 |bibcode=2022PhRvD.106j3530P |s2cid=235247869}}</ref> From third-year data of Galaxy Clustering and Weak Lensing results, DES updated the Cosmological Constraints to <math>S_8=\sigma_8(\Omega_m/0.3)^{0.5}= 0.776_{-0.017}^{+0.017}</math> and <math>\Omega_m= 0.339_{-0.031}^{+0.032}</math> in ΛCDM at 68% confidence limits, <math>S_8=\sigma_8(\Omega_m/0.3)^{0.5}= 0.775_{-0.024}^{+0.026}</math>, <math>\Omega_m= 0.352_{-0.041}^{+0.035}</math> and <math>\omega= -0.98_{-0.20}^{+0.32}</math> in {{not a typo|ωCDM}} at 68% confidence limits.<ref>{{Cite journal |last1=DES Collaboration |last2=Abbott |first2=T. M. C. |last3=Aguena |first3=M. |last4=Alarcon |first4=A. |last5=Allam |first5=S. |last6=Alves |first6=O. |last7=Amon |first7=A. |last8=Andrade-Oliveira |first8=F. |last9=Annis |first9=J. |last10=Avila |first10=S. |last11=Bacon |first11=D. |date=2022-01-13 |title=Dark Energy Survey Year 3 results: Cosmological constraints from galaxy clustering and weak lensing |url=https://link.aps.org/doi/10.1103/PhysRevD.105.023520 |journal=Physical Review D |volume=105 |issue=2 |pages=023520 |doi=10.1103/PhysRevD.105.023520|arxiv=2105.13549 |bibcode=2022PhRvD.105b3520A |hdl=10852/94381 |s2cid=245959154 }}</ref> Similarly, the DES team published their third-year observations for photometric data set for cosmology comprising nearly 5000 deg2 of {{not a typo|grizY}} imaging in the south Galactic cap, including nearly 390 million objects, with depth reaching S/N ~ 10 for extended objects up to <math>i_{AB}</math> ~ 23.0, and top-of-the-atmosphere photometric uniformity < 3mmag.<ref>{{Cite journal |last1=Sevilla-Noarbe |first1=I. |last2=Bechtol |first2=K. |last3=Kind |first3=M. Carrasco |last4=Rosell |first4=A. Carnero |last5=Becker |first5=M. R. |last6=Drlica-Wagner |first6=A. |last7=Gruendl |first7=R. A. |last8=Rykoff |first8=E. S. |last9=Sheldon |first9=E. |last10=Yanny |first10=B. |last11=Alarcon |first11=A. |date=2021-06-01 |title=Dark Energy Survey Year 3 Results: Photometric Data Set for Cosmology |journal=The Astrophysical Journal Supplement Series |volume=254 |issue=2 |pages=24 |doi=10.3847/1538-4365/abeb66 |arxiv=2011.03407 |bibcode=2021ApJS..254...24S |s2cid=226278355 |issn=0067-0049 |doi-access=free }}</ref>

===Weak lensing===

[[File:DESDMmap2021.png|thumb|DES's 2021 Dark matter map<ref name=":0">{{Cite journal|last1=Jeffrey|first1=N|last2=Gatti|first2=M|last3=Chang|first3=C|last4=Whiteway|first4=L|last5=Demirbozan|first5=U|last6=Kovacs|first6=A|last7=Pollina|first7=G|last8=Bacon|first8=D|last9=Hamaus|first9=N|last10=Kacprzak|first10=T|last11=Lahav|first11=O|date=2021-06-25|title=Dark Energy Survey Year 3 results: Curved-sky weak lensing mass map reconstruction|url=https://academic.oup.com/mnras/article/505/3/4626/6287258|journal=Monthly Notices of the Royal Astronomical Society|language=en|volume=505|issue=3|pages=4626–4645|arxiv=2105.13539|doi=10.1093/mnras/stab1495|doi-access=free|issn=0035-8711}}</ref><ref name=":1">{{Cite journal|last=Castelvecchi|first=Davide|date=2021-05-28|title=The most detailed 3D map of the Universe ever made|url=http://www.nature.com/articles/d41586-021-01466-1|journal=Nature|language=en|pages=d41586–021–01466-1|doi=10.1038/d41586-021-01466-1|pmid=34050347|s2cid=235242965|issn=0028-0836}}</ref> using weak gravitational lensing data set projected in the foreground of observed galaxies]]

Weak lensing was measured statistically by measuring the shear-shear [[correlation function]], a two-point function, or its [[Fourier transform|Fourier Transform]], the shear [[power spectrum]].<ref name="DES_prop">{{cite web|url=https://www.darkenergysurvey.org/reports/proposal-standalone.pdf |title=The Dark Energy Survey Science Program|access-date=2010-12-02 |url-status=dead |archive-url=https://web.archive.org/web/20110720152822/https://www.darkenergysurvey.org/reports/proposal-standalone.pdf |archive-date=2011-07-20 }}</ref> In April 2015, the Dark Energy Survey released mass maps using cosmic shear measurements of about 2 million galaxies from the science verification data between August 2012 and February 2013.<ref name="des_mass_map">{{Cite web|url=https://news.fnal.gov/2015/04/mapping-the-cosmos-dark-energy-survey-creates-detailed-guide-to-spotting-dark-matter-2/|title=Mapping the cosmos: Dark Energy Survey creates detailed guide to spotting dark matter|date=13 April 2015}}</ref> In 2021 weak lensing was used to map the dark matter in a region of the southern hemisphere sky,<ref name=":0" /><ref name=":1" /> in 2022 together with galaxy clustering data to give new cosmological constrains.<ref>{{Cite journal|last1=Abbott|first1=T. M. C.|last2=Aguena|first2=M.|last3=Alarcon|first3=A.|last4=Allam|first4=S.|last5=Alves|first5=O.|last6=Amon|first6=A.|last7=Andrade-Oliveira|first7=F.|last8=Annis|first8=J.|last9=Avila|first9=S.|last10=Bacon|first10=D.|last11=Baxter|first11=E.|date=2022-01-13|title=Dark Energy Survey Year 3 results: Cosmological constraints from galaxy clustering and weak lensing|url=https://link.aps.org/doi/10.1103/PhysRevD.105.023520|journal=Physical Review D|language=en|volume=105|issue=2|pages=023520|doi=10.1103/PhysRevD.105.023520|arxiv=2105.13549|bibcode=2022PhRvD.105b3520A|hdl=10852/94381 |s2cid=245959154|issn=2470-0010}}</ref><ref>{{Cite journal|last=Schirber|first=Michael|date=2022-01-13|title=Dark Energy Survey Hits a Triple|url=https://physics.aps.org/articles/v15/s4|journal=Physics|language=en|volume=15|doi=10.1103/Physics.15.s4|bibcode=2022PhyOJ..15...s4S|s2cid=247259733|doi-access=free}}</ref> and in 2023 with data from the [[Planck (spacecraft)|Planck telescope]] and [[South Pole Telescope|South Pole telescope]] to give once new improved constraints.<ref>{{Cite journal |last1=DES and SPT Collaborations |last2=Omori |first2=Y. |last3=Baxter |first3=E. J. |last4=Chang |first4=C. |last5=Friedrich |first5=O. |last6=Alarcon |first6=A. |last7=Alves |first7=O. |last8=Amon |first8=A. |last9=Andrade-Oliveira |first9=F. |last10=Bechtol |first10=K. |last11=Becker |first11=M. R. |last12=Bernstein |first12=G. M. |last13=Blazek |first13=J. |last14=Bleem |first14=L. E. |last15=Camacho |first15=H. |date=2023-01-31 |title=Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and Planck. I. Construction of CMB lensing maps and modeling choices |url=https://link.aps.org/doi/10.1103/PhysRevD.107.023529 |journal=Physical Review D |volume=107 |issue=2 |pages=023529 |doi=10.1103/PhysRevD.107.023529|arxiv=2203.12439 |bibcode=2023PhRvD.107b3529O |hdl=10261/336767 |s2cid=256493553 }}</ref><ref>{{Cite journal |last1=DES & SPT Collaborations |last2=Chang |first2=C. |last3=Omori |first3=Y. |last4=Baxter |first4=E. J. |last5=Doux |first5=C. |last6=Choi |first6=A. |last7=Pandey |first7=S. |last8=Alarcon |first8=A. |last9=Alves |first9=O. |last10=Amon |first10=A. |last11=Andrade-Oliveira |first11=F. |last12=Bechtol |first12=K. |last13=Becker |first13=M. R. |last14=Bernstein |first14=G. M. |last15=Bianchini |first15=F. |date=2023-01-31 |title=Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and $Planck$. II. Cross-correlation measurements and cosmological constraints |url=https://link.aps.org/doi/10.1103/PhysRevD.107.023530 |journal=Physical Review D |volume=107 |issue=2 |pages=023530 |doi=10.1103/PhysRevD.107.023530|arxiv=2203.12440 |bibcode=2023PhRvD.107b3530C |hdl=10261/336776 |s2cid=256480388 }}</ref><ref>{{Cite journal |last1=DES and SPT Collaborations |last2=Abbott |first2=T. M. C. |last3=Aguena |first3=M. |last4=Alarcon |first4=A. |last5=Alves |first5=O. |last6=Amon |first6=A. |last7=Andrade-Oliveira |first7=F. |last8=Annis |first8=J. |last9=Ansarinejad |first9=B. |last10=Avila |first10=S. |last11=Bacon |first11=D. |last12=Baxter |first12=E. J. |last13=Bechtol |first13=K. |last14=Becker |first14=M. R. |last15=Benson |first15=B. A. |date=2023-01-31 |title=Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and Planck. III. Combined cosmological constraints |url=https://link.aps.org/doi/10.1103/PhysRevD.107.023531 |journal=Physical Review D |volume=107 |issue=2 |pages=023531 |doi=10.1103/PhysRevD.107.023531|arxiv=2206.10824 |bibcode=2023PhRvD.107b3531A |hdl=10261/336780 |s2cid=249926390 }}</ref><ref>{{Cite journal |last=Gasparini |first=Allison |date=2023-01-31 |title=Cosmological Parameters Improved by Combining Data |url=https://physics.aps.org/articles/v16/s12 |journal=Physics |language=en |volume=16 |issue=2 |pages=s12 |doi=10.1103/PhysRevD.107.023529|arxiv=2203.12439 |bibcode=2023PhRvD.107b3529O |hdl=10261/336767 |s2cid=256493553 }}</ref>

Another big part of weak lensing result is to calibrate the [[redshift]] of the source galaxies. In December 2020 and June 2021, DES team published two papers showing their results about using weak lensing to calibrate the redshift of the source galaxies in order to mapping the matter density field with gravitational lensing.<ref>{{Cite journal |last1=Gatti |first1=M. |last2=Giannini |first2=G. |last3=Bernstein |first3=G. M. |last4=Alarcon |first4=A. |last5=Myles |first5=J. |last6=Amon |first6=A. |last7=Cawthon |first7=R. |last8=Troxel |first8=M. |last9=DeRose |first9=J. |last10=Everett |first10=S. |last11=Ross |first11=A. J. |date=2021-12-24 |title=Dark Energy Survey Year 3 Results: Clustering Redshifts -- Calibration of the Weak Lensing Source Redshift Distributions with redMaGiC and BOSS/eBOSS |journal=Monthly Notices of the Royal Astronomical Society |volume=510 |issue=1 |pages=1223–1247 |doi=10.1093/mnras/stab3311 |doi-access=free |arxiv=2012.08569 |issn=0035-8711}}</ref><ref>{{Cite journal |last1=Myles |first1=J. |last2=Alarcon |first2=A. |last3=Amon |first3=A. |last4=Sánchez |first4=C. |last5=Everett |first5=S. |last6=DeRose |first6=J. |last7=McCullough |first7=J. |last8=Gruen |first8=D. |last9=Bernstein |first9=G. M. |last10=Troxel |first10=M. A. |last11=Dodelson |first11=S. |date=2021-06-23 |title=Dark Energy Survey Year 3 Results: Redshift Calibration of the Weak Lensing Source Galaxies |journal=Monthly Notices of the Royal Astronomical Society |volume=505 |issue=3 |pages=4249–4277 |doi=10.1093/mnras/stab1515 |doi-access=free |arxiv=2012.08566 |issn=0035-8711}}</ref>

=== Gravitational waves ===
After [[LIGO]] detected the first [[gravitational wave]] signal from GW170817,<ref>{{Cite journal |last1=The LIGO Scientific Collaboration |last2=The Virgo Collaboration |date=2017-10-16 |title=GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral |journal=Physical Review Letters |volume=119 |issue=16 |pages=161101 |doi=10.1103/PhysRevLett.119.161101 |pmid=29099225 |arxiv=1710.05832 |bibcode=2017PhRvL.119p1101A |s2cid=217163611 |issn=0031-9007}}</ref> DES made follow-up observations of GW170817 using DECam. With DECam independent discovery of the optical source, DES team establish its association with GW170817 by showing that none of the 1500 other sources found within the event localization region could plausibly be associated with the event. DES team monitored the source for over two weeks and provide the light curve data as a machine-readable file.  From the observation data set, DES concluded that the optical counterpart they have identified near [[NGC 4993]] is associated with GW170817. This discovery ushers in the era of multi-messenger astronomy with gravitational waves and demonstrates the power of DECam to identify the optical counterparts of gravitational-wave sources.<ref>{{Cite journal |last1=Soares-Santos |first1=M. |last2=Holz |first2=D. E. |last3=Annis |first3=J. |last4=Chornock |first4=R. |last5=Herner |first5=K. |last6=Berger |first6=E. |last7=Brout |first7=D. |last8=Chen |first8=H. |last9=Kessler |first9=R. |last10=Sako |first10=M. |last11=Allam |first11=S. |date=2017-10-16 |title=The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. I. Dark Energy Camera Discovery of the Optical Counterpart |journal=The Astrophysical Journal |volume=848 |issue=2 |pages=L16 |doi=10.3847/2041-8213/aa9059 |arxiv=1710.05459 |s2cid=119399798 |issn=2041-8213 |doi-access=free }}</ref>

=== Dwarf galaxies ===
[[File:Dark Energy Survey - Spiral galaxy NGC 0895 (14935678296).jpg|thumb|Spiral Galaxy [[NGC 895]] imaged by DES]]
In March 2015, two teams released their discoveries of several new potential [[dwarf galaxy]] candidates found in Year 1 DES data.<ref name="des_y1_dwarfs">{{Cite web|url=https://news.fnal.gov/2015/03/scientists-find-rare-dwarf-satellite-galaxy-candidates-in-dark-energy-survey-data-2/|title=Scientists find rare dwarf satellite galaxy candidates in Dark Energy Survey data|date=10 March 2015}}</ref> In August 2015, the Dark Energy Survey team announced the discovery of eight additional candidates in Year 2 DES data.<ref name="des_y2_dwarfs">{{Cite journal|title=Eight Ultra-faint Galaxy Candidates Discovered in Year Two of the Dark Energy Survey|date=November 4, 2015|journal=The Astrophysical Journal|volume=813|issue=2|pages=109|doi=10.1088/0004-637X/813/2/109|arxiv=1508.03622|last1=Drlica-Wagner|first1=A.|last2=Bechtol|first2=K.|last3=Rykoff|first3=E. S.|last4=Luque|first4=E.|last5=Queiroz|first5=A.|last6=Mao|first6=Y.-Y.|last7=Wechsler|first7=R. H.|last8=Simon|first8=J. D.|last9=Santiago|first9=B.|last10=Yanny|first10=B.|last11=Balbinot|first11=E.|last12=Dodelson|first12=S.|last13=Neto|first13=A. Fausti|last14=James|first14=D. J.|last15=Li|first15=T. S.|last16=Maia|first16=M. A. G.|last17=Marshall|first17=J. L.|last18=Pieres|first18=A.|last19=Stringer|first19=K.|last20=Walker|first20=A. R.|last21=Abbott|first21=T. M. C.|last22=Abdalla|first22=F. B.|last23=Allam|first23=S.|last24=Benoit-Lévy|first24=A.|last25=Bernstein|first25=G. M.|last26=Bertin|first26=E.|last27=Brooks|first27=D.|last28=Buckley-Geer|first28=E.|author28-link=Elizabeth Buckley-Geer|last29=Burke|first29=D. L.|last30=Rosell|first30=A. Carnero|bibcode=2015ApJ...813..109D|hdl=10183/140479|s2cid=55909299|display-authors=1}}</ref> Later on, Dark Energy Survey team found more dwarf galaxies. With more Dwarf Galaxy results, the team was able to take a deep look about more properties of the detected Dwarf Galaxy such as the chemical abundance,<ref>{{Cite journal |last1=Hansen |first1=T. T. |last2=Marshall |first2=J. L. |last3=Simon |first3=J. D. |last4=Li |first4=T. S. |last5=Bernstein |first5=R. A. |last6=Pace |first6=A. B. |last7=Ferguson |first7=P. |last8=Nagasawa |first8=D. Q. |last9=Kuehn |first9=K. |last10=Carollo |first10=D. |last11=Geha |first11=M. |author11-link= Marla Geha |date=2020-07-16 |title=Chemical Analysis of the Ultrafaint Dwarf Galaxy Grus II. Signature of High-mass Stellar Nucleosynthesis |journal=The Astrophysical Journal |volume=897 |issue=2 |pages=183 |doi=10.3847/1538-4357/ab9643 |arxiv=2005.10767 |bibcode=2020ApJ...897..183H |hdl=10261/234987 |s2cid=218763518 |issn=1538-4357 |doi-access=free }}</ref> the structure of stellar population,<ref>{{Cite journal |last1=Wang |first1=M. Y. |last2=de Boer |first2=T. |last3=Pieres |first3=A. |last4=Li |first4=T. S. |last5=Drlica-Wagner |first5=A. |last6=Koposov |first6=S. E. |last7=Vivas |first7=A. K. |last8=Pace |first8=A. B. |last9=Santiago |first9=B. |last10=Walker |first10=A. R. |last11=Tucker |first11=D. L. |date=2019-08-21 |title=The Morphology and Structure of Stellar Populations in the Fornax Dwarf Spheroidal Galaxy from Dark Energy Survey Data |journal=The Astrophysical Journal |volume=881 |issue=2 |pages=118 |doi=10.3847/1538-4357/ab31a9 |arxiv=1809.07801 |bibcode=2019ApJ...881..118W |s2cid=119088745 |issn=1538-4357 |doi-access=free }}</ref> and Stellar Kinematics and Metallicities.<ref>{{Cite journal |last1=Simon |first1=J. D. |last2=Drlica-Wagner |first2=A. |last3=Li |first3=T. S. |last4=Nord |first4=B. |last5=Geha |first5=M.|author5-link= Marla Geha |last6=Bechtol |first6=K. |last7=Balbinot |first7=E. |last8=Buckley-Geer |first8=E.|author8-link=Elizabeth Buckley-Geer |last9=Lin |first9=H. |last10=Marshall |first10=J. |last11=Santiago |first11=B. |title=Stellar Kinematics and Metallicities in the Ultra-Faint Dwarf Galaxy Reticulum Ii |date=2015-07-23 |url=https://iopscience.iop.org/article/10.1088/0004-637X/808/1/95 |journal=The Astrophysical Journal |volume=808 |issue=1 |pages=95 |doi=10.1088/0004-637X/808/1/95 |arxiv=1504.02889 |bibcode=2015ApJ...808...95S |hdl=1969.1/185483 |s2cid=17352150 |issn=1538-4357}}</ref> In Feb 2019, the team also discovered a sixth star cluster in the [[Fornax Dwarf]] Spheroidal Galaxy<ref>{{Cite journal |last1=Wang |first1=M. Y. |last2=Koposov |first2=S. |last3=Drlica-Wagner |first3=A. |last4=Pieres |first4=A. |last5=Li |first5=T. S. |last6=de Boer |first6=T. |last7=Bechtol |first7=K. |last8=Belokurov |first8=V. |last9=Pace |first9=A. B. |last10=Bacon |first10=D. |last11=Abbott |first11=T. M. C. |date=2019-04-16 |title=Rediscovery of the Sixth Star Cluster in the Fornax Dwarf Spheroidal Galaxy |journal=The Astrophysical Journal |volume=875 |issue=2 |pages=L13 |doi=10.3847/2041-8213/ab14f5 |arxiv=1902.04589 |bibcode=2019ApJ...875L..13W |s2cid=119044713 |issn=2041-8213 |doi-access=free }}</ref> and a tidally Disrupted Ultra-Faint Dwarf Galaxy.<ref>{{Cite journal |last1=Li |first1=T. S. |last2=Simon |first2=J. D. |last3=Kuehn |first3=K. |last4=Pace |first4=A. B. |last5=Erkal |first5=D. |last6=Bechtol |first6=K. |last7=Yanny |first7=B. |last8=Drlica-Wagner |first8=A. |last9=Marshall |first9=J. L. |last10=Lidman |first10=C. |last11=Balbinot |first11=E. |date=2018-10-05 |title=The First Tidally Disrupted Ultra-faint Dwarf Galaxy?: A Spectroscopic Analysis of the Tucana III Stream |journal=The Astrophysical Journal |volume=866 |issue=1 |pages=22 |doi=10.3847/1538-4357/aadf91 |arxiv=1804.07761 |bibcode=2018ApJ...866...22L |hdl=1885/186419 |s2cid=55274010 |issn=1538-4357 |doi-access=free }}</ref>

=== Baryon acoustic oscillations ===
The signature of [[baryon acoustic oscillations]] (BAO) can be observed in the distribution of tracers of the matter density field and used to measure the expansion history of the Universe. BAO can also be measured using purely photometric data, though at less significance.<ref>{{Cite journal |last1=The Dark Energy Survey Collaboration |last2=Abbott |first2=T. M. C. |last3=Abdalla |first3=F. B. |last4=Alarcon |first4=A. |last5=Allam |first5=S. |last6=Andrade-Oliveira |first6=F. |last7=Annis |first7=J. |last8=Avila |first8=S. |last9=Banerji |first9=M. |last10=Banik |first10=N. |last11=Bechtol |first11=K. |date=2019-03-11 |title=Dark Energy Survey Year 1 Results: Measurement of the Baryon Acoustic Oscillation scale in the distribution of galaxies to redshift 1 |journal=Monthly Notices of the Royal Astronomical Society |volume=483 |issue=4 |pages=4866–4883 |doi=10.1093/mnras/sty3351 |doi-access=free |arxiv=1712.06209 |issn=0035-8711}}</ref> DES team observation samples consists of 7 million galaxies distributed over a footprint of 4100 deg<sup>2</sup> with {{nowrap|0.6 < z<sub>photo</sub> < 1.1}} and a typical redshift uncertainty of 0.03(1+z).<ref>{{Cite journal |last1=Rosell |first1=A. Carnero |last2=Rodriguez-Monroy |first2=M. |last3=Crocce |first3=M. |last4=Elvin-Poole |first4=J. |last5=Porredon |first5=A. |last6=Ferrero |first6=I. |last7=Mena-Fernandez |first7=J. |last8=Cawthon |first8=R. |last9=De Vicente |first9=J. |last10=Gaztanaga |first10=E. |last11=Ross |first11=A. J. |date=2021-11-10 |title=Dark Energy Survey Year 3 Results: Galaxy Sample for BAO Measurement |journal=Monthly Notices of the Royal Astronomical Society |volume=509 |issue=1 |pages=778–799 |doi=10.1093/mnras/stab2995 |doi-access=free |arxiv=2107.05477 |issn=0035-8711}}</ref> From their statistics, they combine the likelihoods derived from angular correlations and spherical harmonics to constrain the ratio of comoving angular diameter distance <math>D_m(Z_eff = 0.835)/r_d=18.92\pm0.51</math> at the effective redshift of our sample to the sound horizon scale at the drag epoch.<ref>{{Cite journal |last1=DES Collaboration |last2=Abbott |first2=T. M. C. |last3=Aguena |first3=M. |last4=Allam |first4=S. |last5=Andrade-Oliveira |first5=F. |last6=Asorey |first6=J. |last7=Avila |first7=S. |last8=Bernstein |first8=G. M. |last9=Bertin |first9=E. |last10=Brandao-Souza |first10=A. |last11=Brooks |first11=D. |date=2022-02-08 |title=Dark Energy Survey Year 3 Results: A 2.7% measurement of Baryon Acoustic Oscillation distance scale at redshift 0.835 |journal=Physical Review D |volume=105 |issue=4 |pages=043512 |doi=10.1103/PhysRevD.105.043512 |arxiv=2107.04646 |bibcode=2022PhRvD.105d3512A |hdl=10852/94783 |s2cid=235795204 |issn=2470-0010}}</ref>
[[File:G299-Remnants-SuperNova-Type1a-20150218.jpg|thumb|The supernova remnant  [[G299.2-2.9]]]]

=== Type Ia supernova observations===
In May 2019, Dark Energy Survey team published their first cosmology results using [[Type Ia supernova]]e. The supernova data was from DES-SN3YR. The Dark Energy Survey team found Ωm = 0.331 ± 0.038 with a flat ΛCDM model and Ωm = 0.321 ± 0.018, w = −0.978 ± 0.059 with a flat {{not a typo|wCDM}} model.<ref>{{Cite journal |last1=Abbott |first1=T. M. C. |last2=Allam |first2=S. |last3=Andersen |first3=P. |last4=Angus |first4=C. |last5=Asorey |first5=J. |last6=Avelino |first6=A. |last7=Avila |first7=S. |last8=Bassett |first8=B. A. |last9=Bechtol |first9=K. |last10=Bernstein |first10=G. M. |last11=Bertin |first11=E. |date=2019-02-21 |title=First Cosmology Results using Type Ia Supernovae from the Dark Energy Survey: Constraints on Cosmological Parameters |journal=The Astrophysical Journal |volume=872 |issue=2 |pages=L30 |doi=10.3847/2041-8213/ab04fa |arxiv=1811.02374 |bibcode=2019ApJ...872L..30A |s2cid=84833144 |issn=2041-8213 |doi-access=free }}</ref> Analyzing the same data from DES-SN3YR, they also found a new current [[Hubble constant]], <math>H_0= 67.1 \pm1.3\,\mathrm{km\,s^{-1}\,Mpc^{-1}}</math>.<ref>{{Cite journal |last1=Macaulay |first1=E. |last2=Nichol |first2=R. C. |last3=Bacon |first3=D. |last4=Brout |first4=D. |last5=Davis |first5=T. M. |last6=Zhang |first6=B. |last7=Bassett |first7=B. A. |last8=Scolnic |first8=D. |last9=Möller |first9=A. |last10=D'Andrea |first10=C. B. |last11=Hinton |first11=S. R. |date=2019-06-21 |title=First Cosmological Results using Type Ia Supernovae from the Dark Energy Survey: Measurement of the Hubble Constant |journal=Monthly Notices of the Royal Astronomical Society |volume=486 |issue=2 |pages=2184–2196 |doi=10.1093/mnras/stz978 |doi-access=free |arxiv=1811.02376 |issn=0035-8711}}</ref> This result has an excellent agreement with the Hubble constant measurement from Planck Satellite Collaboration in 2018.<ref>{{Cite journal |last1=Larivière |first1=Vincent |last2=Sugimoto |first2=Cassidy R. |author2-link=Cassidy Sugimoto |last3=Macaluso |first3=Benoit |last4=Milojević |first4=Staša |last5=Cronin |first5=Blaise |last6=Thelwall |first6=Mike |date=2014-01-27 |title=arXiv E-prints and the journal of record: An analysis of roles and relationships |url=http://dx.doi.org/10.1002/asi.23044 |journal=Journal of the Association for Information Science and Technology |volume=65 |issue=6 |pages=1157–1169 |arxiv=1306.3261 |bibcode=2014JASIS..65.1157L |doi=10.1002/asi.23044 |issn=2330-1635 |s2cid=30584899}}</ref> In June 2019, there a follow-up paper was published by DES team discussing the systematic uncertainties, and validation of using the supernovae to measure the cosmology results mentioned before.<ref>{{Cite journal |last1=Brout |first1=D. |last2=Scolnic |first2=D. |last3=Kessler |first3=R. |last4=D'Andrea |first4=C. B. |last5=Davis |first5=T. M. |last6=Gupta |first6=R. R. |last7=Hinton |first7=S. R. |last8=Kim |first8=A. G. |last9=Lasker |first9=J. |last10=Lidman |first10=C. |last11=Macaulay |first11=E. |date=2019-04-02 |title=First Cosmology Results Using Type Ia Supernovae From the Dark Energy Survey: Analysis, Systematic Uncertainties, and Validation |journal=The Astrophysical Journal |volume=874 |issue=2 |pages=150 |doi=10.3847/1538-4357/ab08a0 |arxiv=1811.02377 |s2cid=119537585 |issn=1538-4357 |doi-access=free }}</ref> The team also published their photometric pipeline and light curve data in another paper published in the same month.<ref>{{Cite journal |last1=Brout |first1=D. |last2=Sako |first2=M. |last3=Scolnic |first3=D. |last4=Kessler |first4=R. |last5=D'Andrea |first5=C. B. |last6=Davis |first6=T. M. |last7=Hinton |first7=S. R. |last8=Kim |first8=A. G. |last9=Lasker |first9=J. |last10=Macaulay |first10=E. |last11=Möller |first11=A. |date=2019-03-27 |title=First Cosmology Results Using Type Ia Supernovae From the Dark Energy Survey: Photometric Pipeline and Light Curve Data Release |journal=The Astrophysical Journal |volume=874 |issue=1 |pages=106 |doi=10.3847/1538-4357/ab06c1 |arxiv=1811.02378 |bibcode=2019ApJ...874..106B |s2cid=102487487 |issn=1538-4357 |doi-access=free }}</ref>

===Minor planets===
Several [[minor planets]] were discovered by DeCam in the course of ''The Dark Energy Survey'', including high-inclination [[trans-Neptunian object]]s (TNOs).<ref>{{cite journal |author1=Becker, J.C. |author2=Khain, T. |author3=Hamilton, S.J. |author4=Adams, F.C. |author5=Gerdes, D.W. |author6=Zullo, L. |display-authors=etal |collaboration=DES Collaboration |year=2018 |title=Discovery and dynamical analysis of an extreme trans-Neptunian object with a high orbital inclination |journal=[[The Astronomical Journal]] |volume=156 |issue=2 |page=81 |doi=10.3847/1538-3881/aad042 |arxiv=1805.05355 |bibcode=2018AJ....156...81B |s2cid=55163842 |doi-access=free }}</ref>

:{| class="wikitable" style="font-size:89%; float:left; text-align:center; width:27em; margin-right:1em; line-height:1.65em !important; height:155px;"
 |+ List of DES discovered minor planets 
 |-
 ! Numbered MP<br/>designation  !!  Discovery<br/>date
 !style="width:3em;" | {{small|MP list link}}
 ! Ref
 |-
 | {{mpl|(451657) 2012 WD|36}} 
 | 19 November 2012
 | {{small|{{LoMP|451657|list}}}}
 | <ref>{{cite web |title=JPL Small-Body Database Browser |website=ssd.jpl.nasa.gov |id=2 451657 |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2451657}}</ref>
 |-
 | {{mpl|(471954) 2013 RM|98}} 
 | 8 September 2013
 | {{small|{{LoMP|471954|list}}}}
 | <ref>{{cite web |first=Alan |last=Chamberlin |title=JPL Small-Body Database Browser |id=2 471954 |website=ssd.jpl.nasa.gov |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2471954}}</ref>
 |-
 | {{mpl|(472262) 2014 QN|441}} 
 | 18 August 2014
 | {{small|{{LoMP|472262|list}}}}
 | <ref>{{cite web |title=JPL Small-Body Database Browser |website=ssd.jpl.nasa.gov |id=2 472262 |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2472262}}</ref>
 |-
 | {{mpl|(483002) 2014 QS|441}} 
 | 19 August 2014
 | {{small|{{LoMP|483002|list}}}}
 | <ref>{{cite web |title=JPL Small-Body Database Browser |website=ssd.jpl.nasa.gov |id=2 483002 |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2483002}}</ref>
 |-
 | {{mpl|(491767) 2012 VU|113}} 
 | 15 November 2012
 | {{small|{{LoMP|491767|list}}}}
 | <ref>{{cite web |title=JPL Small-Body Database Browser |website=ssd.jpl.nasa.gov |id=2 491767 |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2491767}}</ref>
 |-
 | {{mpl|(491768) 2012 VV|113}} 
 | 15 November 2012
 | {{small|{{LoMP|491768|list}}}}
 | <ref>{{cite web |title=JPL Small-Body Database Browser |website=ssd.jpl.nasa.gov |id=2 491768 |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2491768}}</ref>
 |-
 | {{mpl|(495189) 2012 VR|113}} 
 | 28 September 2012
 | {{small|{{LoMP|495189|list}}}}
 | <ref>{{cite web |title=JPL Small-Body Database Browser |website=ssd.jpl.nasa.gov |id=2 495189 |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2495189}}</ref>
 |-
 | {{mpl|(495190) 2012 VS|113}} 
 | 12 November 2012
 | {{small|{{LoMP|495190|list}}}}
 | <ref>{{cite web |title=JPL Small-Body Database Browser |website=ssd.jpl.nasa.gov |id=2 495190 |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2495190}}</ref>
 |-
 | {{mpl|(495297) 2013 TJ|159}}
 | 13 October 2013
 | {{small|{{LoMP|495297|list}}}}
 | <ref>{{cite web |title=JPL Small-Body Database Browser |website=ssd.jpl.nasa.gov |id=2 495297 |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2495297}}</ref>
 |-
 !colspan=4 style="font-weight:normal; text-align:center; padding:4px 12px;"| Discoveries are credited either to<br/>"DECam" or "Dark Energy Survey".
|}

{{clear}}

The MPC has assigned the [[IAU code]] [[IAU code#W84|W84]] for DeCam's observations of small Solar System bodies. As of October&nbsp;2019, the MPC inconsistently credits the discovery of nine numbered minor planets, all of them [[trans-Neptunian objects]], to either "DeCam" or "Dark Energy Survey".<ref name=MPC-Discoverers/> The list does not contain any unnumbered minor planets potentially discovered by DeCam, as discovery credits are only given upon a body's numbering, which in turn depends on a sufficiently secure orbit determination.

== Gallery ==
<gallery heights="150" mode="packed">
File:Dark Energy Survey deep field image.jpg|alt=Dark Energy Survey deep field image|{{center|Dark Energy Survey [[List of deep fields|deep field image]]}}<ref>{{cite news|title=Dark Energy Survey Releases Most Precise Look at the Universe's Evolution|url=https://noirlab.edu/public/news/noirlab2118/|access-date=17 June 2021|newspaper=NOIRLab Press Release}}</ref>
File:Dark Energy Survey - distant galaxies (14958324522).jpg|The large spiral galaxy in the center of this image is roughly 385 million light-years from Earth.
File:Dark Energy Survey - Fornax cluster (14958323932).jpg|The three large objects in this image captured by the Dark Energy Camera are galaxies in the nearby Fornax cluster, roughly 65 million light-years from Earth.
File:Dark Energy Survey - galaxy NGC 1398 (14935678916).jpg|Dark Energy Survey - galaxy [[NGC 1398]]
</gallery>

== See also ==

* [[Cosmic Evolution Survey]]

== References ==
{{Reflist|refs=

<ref name="MPC-Discoverers">{{cite web
  |title      = Minor Planet Discoverers (by number)
  |work       = Minor Planet Center
  |url        = http://www.minorplanetcenter.net/iau/lists/MPDiscsNum.html
  |date       = 15 November 2016
  |access-date = 27 January 2017}}</ref>

}} <!-- end of reflist -->

== External links ==
* [http://www.darkenergysurvey.org/ Dark Energy Survey website]
* [https://web.archive.org/web/20110720152822/https://www.darkenergysurvey.org/reports/proposal-standalone.pdf Dark Energy Survey Science Program (PDF)]
* [https://opensource.ncsa.illinois.edu/confluence/display/DESDM/The+Dark+Energy+Survey+Data+Management+Project Dark Energy Survey Data Management ]
* [http://www.ctio.noao.edu/noao/node/1033 Dark Energy Camera (DECam)] {{Webarchive|url=https://web.archive.org/web/20171018104923/http://www.ctio.noao.edu/noao/node/1033 |date=2017-10-18 }}
* {{Cite web |last=Biron |first=Lauren |title=15 spectacular photos from the Dark Energy Camera |url=https://www.symmetrymagazine.org/article/15-spectacular-photos-from-the-dark-energy-camera |website=symmetry magazine |date=4 October 2022 |language=en}}

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[[Category:Fermilab experiments]]
[[Category:Minor-planet discovering observatories]]