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Dark Energy Survey

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, and near-infrared to measure the expansion of the universe using Type Ia supernovae, baryon acoustic oscillations, the number of galaxy clusters, and weak gravitational lensing.[1] The collaboration is composed of research institutions and universities from the United States,[2] Australia, Brazil,[3] the United Kingdom, Germany, Spain, and Switzerland. The collaboration is divided into several scientific working groups. The director of DES is Josh Frieman.[4]

The Dark Energy Survey
Dark Energy Survey logo
Alternative namesDES
Websitewww.darkenergysurvey.org
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The DES began by developing and building Dark Energy Camera (DECam), an instrument designed specifically for the survey.[5] 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.[6] 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.[6] Observing sessions ran from 2013 to 2019; as of 2021 the DES collaboration has published results from the first three years of the survey.[7]

DECam edit

 
A Sky Full of Galaxies.[8]

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 CCDs.

Mechanics edit

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 cm in diameter. These components are attached to the CCD focal plane which is cooled to 173 K (−148 °F; −100 °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 0.00013 pascals (1.3×10−9 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 hexapod system allowing for real time focal adjustment.[9]

Optics edit

The camera is outfitted with u, g, r, i, z, and Y filters spanning roughly from 340–1070 nm,[10] similar to those used in the 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.[6] One significant difference between previous charge-coupled devices (CCD) at the Victor M. Blanco Telescope and DECam is the improved quantum efficiency in the red and near-infrared wavelengths.[11][9]

CCDs edit

 
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 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 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 interaction and allows the CCDs to have an increased sensitivity to lower energy photons, extending the wavelength range to 1050 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″ on the sky, resulting in a total field of view of 3 square degrees.[12]

Survey edit

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 bands (g, r, i, z, and Y).[13] The survey reached a depth of 24th 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.[14]

First light was achieved on 12 September 2012;[15] after a verification and testing period, scientific survey observations started in August 2013.[16] The last observing session was completed on 9 January 2019.[13]

Other surveys using DECam edit

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.[17][18]
  • 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 southern sky, including parts of the Magellanic Clouds. The purpose of the Legacy Surveys is to find targets for the Dark Energy Spectroscopic Instrument.[18][19]
  • Dark Energy Camera Plane Survey (DECaPS), covers the Milky Way in the southern sky.[20]
 
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.

Observing edit

 
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 seconds long, with another 30 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.[21]

Results edit

Cosmology edit

 
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,   and   for ΛCDM,  ,   and   at 68% confidence limits for ωCMD.[22] Combine the most significant measurements of cosmic shear in a galaxy survey, Dark Energy Survey Group showed that   at 68% confidence limits and   for ΛCDM with  .[23] 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.[24] The DES team also published a paper summarize all the Photometric Data Set for Cosmology for their first-year data.[25]

For the third-year data collected by DES, they updated the Cosmological Constraints to   for the ΛCDM model with the new cosmic shear measurements.[26] From third-year data of Galaxy Clustering and Weak Lensing results, DES updated the Cosmological Constraints to   and   in ΛCDM at 68% confidence limits,  ,   and   in ωCDM at 68% confidence limits.[27] Similarly, the DES team published their third-year observations for photometric data set for cosmology comprising nearly 5000 deg2 of grizY imaging in the south Galactic cap, including nearly 390 million objects, with depth reaching S/N ~ 10 for extended objects up to   ~ 23.0, and top-of-the-atmosphere photometric uniformity < 3mmag.[28]

Weak lensing edit

 
DES's 2021 Dark matter map[29][30] 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, the shear power spectrum.[31] 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.[32] In 2021 weak lensing was used to map the dark matter in a region of the southern hemisphere sky,[29][30] in 2022 together with galaxy clustering data to give new cosmological constrains.[33][34] and in 2023 with data from the Planck telescope and South Pole telescope to give once new improved constraints.[35][36][37][38]

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.[39][40]

Gravitational waves edit

After LIGO detected the first gravitational wave signal from GW170817,[41] 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.[42]

Dwarf galaxies edit

 
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.[43] In August 2015, the Dark Energy Survey team announced the discovery of eight additional candidates in Year 2 DES data.[44] 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,[45] the structure of stellar population,[46] and Stellar Kinematics and Metallicities.[47] In Feb 2019, the team also discovered a sixth star cluster in the Fornax Dwarf Spheroidal Galaxy[48] and a tidally Disrupted Ultra-Faint Dwarf Galaxy.[49]

Baryon acoustic oscillations edit

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.[50] DES team observation samples consists of 7 million galaxies distributed over a footprint of 4100 deg2 with 0.6 < zphoto < 1.1 and a typical redshift uncertainty of 0.03(1+z).[51] From their statistics, they combine the likelihoods derived from angular correlations and spherical harmonics to constrain the ratio of comoving angular diameter distance   at the effective redshift of our sample to the sound horizon scale at the drag epoch.[52]

 
SuperNova-Type1a

Type Ia supernova observations edit

In May 2019, Dark Energy Survey team published their first cosmology results using Type Ia supernovae. 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 wCDM model.[53] Analyzing the same data from DES-SN3YR, they also found a new current Hubble constant,  .[54] This result has an excellent agreement with the Hubble constant measurement from Planck Satellite Collaboration in 2018.[55] 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.[56] The team also published their photometric pipeline and light curve data in another paper published in the same month.[57]

Minor planets edit

Several minor planets were discovered by DeCam in the course of The Dark Energy Survey, including high-inclination trans-Neptunian objects (TNOs).[58]

List of DES discovered minor planets
Numbered MP
designation
Discovery
date
MP list link Ref
(451657) 2012 WD36 19 November 2012 list [59]
(471954) 2013 RM98 8 September 2013 list [60]
(472262) 2014 QN441 18 August 2014 list [61]
(483002) 2014 QS441 19 August 2014 list [62]
(491767) 2012 VU113 15 November 2012 list [63]
(491768) 2012 VV113 15 November 2012 list [64]
(495189) 2012 VR113 28 September 2012 list [65]
(495190) 2012 VS113 12 November 2012 list [66]
(495297) 2013 TJ159 13 October 2013 list [67]
Discoveries are credited either to
"DECam" or "Dark Energy Survey".

The MPC has assigned the IAU code W84 for DeCam's observations of small Solar System bodies. As of October 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".[68] 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 edit

See also edit

References edit

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External links edit

  • Dark Energy Survey website
  • Dark Energy Survey Data Management
  • Dark Energy Camera (DECam) 2017-10-18 at the Wayback Machine
  • Biron, Lauren (4 October 2022). "15 spectacular photos from the Dark Energy Camera". symmetry magazine.

dark, energy, survey, astronomical, survey, designed, constrain, properties, dark, energy, uses, images, taken, near, ultraviolet, visible, near, infrared, measure, expansion, universe, using, type, supernovae, baryon, acoustic, oscillations, number, galaxy, c. 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 and near infrared to measure the expansion of the universe using Type Ia supernovae baryon acoustic oscillations the number of galaxy clusters and weak gravitational lensing 1 The collaboration is composed of research institutions and universities from the United States 2 Australia Brazil 3 the United Kingdom Germany Spain and Switzerland The collaboration is divided into several scientific working groups The director of DES is Josh Frieman 4 The Dark Energy SurveyDark Energy Survey logoAlternative namesDESWebsitewww wbr darkenergysurvey wbr org Related media on Commons edit on Wikidata The DES began by developing and building Dark Energy Camera DECam an instrument designed specifically for the survey 5 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 6 Observations were performed with DECam mounted on the 4 meter Victor M Blanco Telescope located at the Cerro Tololo Inter American Observatory CTIO in Chile 6 Observing sessions ran from 2013 to 2019 as of 2021 update the DES collaboration has published results from the first three years of the survey 7 Contents 1 DECam 1 1 Mechanics 1 2 Optics 1 3 CCDs 2 Survey 2 1 Other surveys using DECam 3 Observing 4 Results 4 1 Cosmology 4 2 Weak lensing 4 3 Gravitational waves 4 4 Dwarf galaxies 4 5 Baryon acoustic oscillations 4 6 Type Ia supernova observations 4 7 Minor planets 5 Gallery 6 See also 7 References 8 External linksDECam edit nbsp A Sky Full of Galaxies 8 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 CCDs Mechanics edit 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 cm in diameter These components are attached to the CCD focal plane which is cooled to 173 K 148 F 100 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 0 00013 pascals 1 3 10 9 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 hexapod system allowing for real time focal adjustment 9 Optics edit The camera is outfitted with u g r i z and Y filters spanning roughly from 340 1070 nm 10 similar to those used in the 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 6 One significant difference between previous charge coupled devices CCD at the Victor M Blanco Telescope and DECam is the improved quantum efficiency in the red and near infrared wavelengths 11 9 CCDs edit nbsp 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 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 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 interaction and allows the CCDs to have an increased sensitivity to lower energy photons extending the wavelength range to 1050 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 on the sky resulting in a total field of view of 3 square degrees 12 Survey editDES 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 bands g r i z and Y 13 The survey reached a depth of 24th 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 14 First light was achieved on 12 September 2012 15 after a verification and testing period scientific survey observations started in August 2013 16 The last observing session was completed on 9 January 2019 13 Other surveys using DECam edit 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 17 18 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 southern sky including parts of the Magellanic Clouds The purpose of the Legacy Surveys is to find targets for the Dark Energy Spectroscopic Instrument 18 19 Dark Energy Camera Plane Survey DECaPS covers the Milky Way in the southern sky 20 nbsp 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 Observing edit nbsp 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 seconds long with another 30 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 21 Results editCosmology edit nbsp Constraints on a measure of the clumpiness of the matter distribution S8 and the fractional density of the Universe in matter Wm 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 S 8 s 8 W m 0 3 0 5 0 773 0 020 0 026 displaystyle S 8 sigma 8 Omega m 0 3 0 5 0 773 0 020 0 026 nbsp and W m 0 267 0 017 0 030 displaystyle Omega m 0 267 0 017 0 030 nbsp for LCDM S 8 0 782 0 024 0 036 displaystyle S 8 0 782 0 024 0 036 nbsp W m 0 284 0 030 0 033 displaystyle Omega m 0 284 0 030 0 033 nbsp and w 0 82 0 20 0 21 displaystyle omega 0 82 0 20 0 21 nbsp at 68 confidence limits for wCMD 22 Combine the most significant measurements of cosmic shear in a galaxy survey Dark Energy Survey Group showed that s 8 W m 0 3 0 5 0 782 0 027 0 027 displaystyle sigma 8 Omega m 0 3 0 5 0 782 0 027 0 027 nbsp at 68 confidence limits and s 8 W m 0 3 0 5 0 777 0 038 0 036 displaystyle sigma 8 Omega m 0 3 0 5 0 777 0 038 0 036 nbsp for LCDM with w 0 95 0 36 0 33 displaystyle omega 0 95 0 36 0 33 nbsp 23 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 24 The DES team also published a paper summarize all the Photometric Data Set for Cosmology for their first year data 25 For the third year data collected by DES they updated the Cosmological Constraints to s 8 W m 0 3 0 5 0 759 0 025 0 023 displaystyle sigma 8 Omega m 0 3 0 5 0 759 0 025 0 023 nbsp for the LCDM model with the new cosmic shear measurements 26 From third year data of Galaxy Clustering and Weak Lensing results DES updated the Cosmological Constraints to S 8 s 8 W m 0 3 0 5 0 776 0 017 0 017 displaystyle S 8 sigma 8 Omega m 0 3 0 5 0 776 0 017 0 017 nbsp and W m 0 339 0 031 0 032 displaystyle Omega m 0 339 0 031 0 032 nbsp in LCDM at 68 confidence limits S 8 s 8 W m 0 3 0 5 0 775 0 024 0 026 displaystyle S 8 sigma 8 Omega m 0 3 0 5 0 775 0 024 0 026 nbsp W m 0 352 0 041 0 035 displaystyle Omega m 0 352 0 041 0 035 nbsp and w 0 98 0 20 0 32 displaystyle omega 0 98 0 20 0 32 nbsp in wCDM at 68 confidence limits 27 Similarly the DES team published their third year observations for photometric data set for cosmology comprising nearly 5000 deg2 of grizY imaging in the south Galactic cap including nearly 390 million objects with depth reaching S N 10 for extended objects up to i A B displaystyle i AB nbsp 23 0 and top of the atmosphere photometric uniformity lt 3mmag 28 Weak lensing edit nbsp DES s 2021 Dark matter map 29 30 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 the shear power spectrum 31 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 32 In 2021 weak lensing was used to map the dark matter in a region of the southern hemisphere sky 29 30 in 2022 together with galaxy clustering data to give new cosmological constrains 33 34 and in 2023 with data from the Planck telescope and South Pole telescope to give once new improved constraints 35 36 37 38 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 39 40 Gravitational waves edit After LIGO detected the first gravitational wave signal from GW170817 41 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 42 Dwarf galaxies edit nbsp 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 43 In August 2015 the Dark Energy Survey team announced the discovery of eight additional candidates in Year 2 DES data 44 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 45 the structure of stellar population 46 and Stellar Kinematics and Metallicities 47 In Feb 2019 the team also discovered a sixth star cluster in the Fornax Dwarf Spheroidal Galaxy 48 and a tidally Disrupted Ultra Faint Dwarf Galaxy 49 Baryon acoustic oscillations edit 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 50 DES team observation samples consists of 7 million galaxies distributed over a footprint of 4100 deg2 with 0 6 lt zphoto lt 1 1 and a typical redshift uncertainty of 0 03 1 z 51 From their statistics they combine the likelihoods derived from angular correlations and spherical harmonics to constrain the ratio of comoving angular diameter distance D m Z e f f 0 835 r d 18 92 0 51 displaystyle D m Z e ff 0 835 r d 18 92 pm 0 51 nbsp at the effective redshift of our sample to the sound horizon scale at the drag epoch 52 nbsp SuperNova Type1a Type Ia supernova observations edit In May 2019 Dark Energy Survey team published their first cosmology results using Type Ia supernovae The supernova data was from DES SN3YR The Dark Energy Survey team found Wm 0 331 0 038 with a flat LCDM model and Wm 0 321 0 018 w 0 978 0 059 with a flat wCDM model 53 Analyzing the same data from DES SN3YR they also found a new current Hubble constant H 0 67 1 1 3 k m s 1 M p c 1 displaystyle H 0 67 1 pm 1 3 mathrm km s 1 Mpc 1 nbsp 54 This result has an excellent agreement with the Hubble constant measurement from Planck Satellite Collaboration in 2018 55 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 56 The team also published their photometric pipeline and light curve data in another paper published in the same month 57 Minor planets edit Several minor planets were discovered by DeCam in the course of The Dark Energy Survey including high inclination trans Neptunian objects TNOs 58 List of DES discovered minor planets Numbered MPdesignation Discoverydate MP list link Ref 451657 2012 WD36 19 November 2012 list 59 471954 2013 RM98 8 September 2013 list 60 472262 2014 QN441 18 August 2014 list 61 483002 2014 QS441 19 August 2014 list 62 491767 2012 VU113 15 November 2012 list 63 491768 2012 VV113 15 November 2012 list 64 495189 2012 VR113 28 September 2012 list 65 495190 2012 VS113 12 November 2012 list 66 495297 2013 TJ159 13 October 2013 list 67 Discoveries are credited either to DECam or Dark Energy Survey The MPC has assigned the IAU code W84 for DeCam s observations of small Solar System bodies As of October 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 68 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 edit nbsp Dark Energy Survey deep field image 69 nbsp The large spiral galaxy in the center of this image is roughly 385 million light years from Earth nbsp 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 nbsp Dark Energy Survey galaxy NGC 1398See also editCosmic Evolution SurveyReferences edit Home The Dark Energy Survey DES Collaboration Page DES Collaborators DES Brazil Archived 2014 10 22 at the Wayback Machine DES Brazil Consortium The Dark Energy Survey Collaboration www darkenergysurvey org Retrieved 2015 11 21 The Project The Dark Energy Survey Collaboration The DES Project Site a b c Dark Energy Camera DECam Archived 2019 05 23 at the Wayback Machine Cerro Tololo Inter American Observatory DES Year 3 Cosmology Results Papers The Dark Energy Survey Retrieved 3 August 2021 A Sky Full of Galaxies NOIRLab Retrieved 12 March 2021 a b DECam Presentation Archived 2011 09 27 at the Wayback Machine 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 Camera SDSS Flaugher Brenna L et al September 24 2012 Status of the Dark Energy Survey Camera DECam project In McLean Ian S Ramsay Suzanne K Takami Hideki eds Ground based and Airborne Instrumentation for Astronomy IV Vol 8446 International Society for Optics and Photonics pp 343 357 doi 10 1117 12 926216 S2CID 121613505 via www spiedigitallibrary org The Camera The Dark Energy Survey Retrieved 2024 05 02 a b NOAO A Survey Machine and a Data Trove Dark Energy Survey s Rich Legacy CTIO www ctio noao edu Archived from the original on 22 September 2021 Retrieved 3 August 2021 Dark Energy Survey Collaboration Description of the Dark Energy Survey for Astronomers PDF The Dark Energy Survey Retrieved 1 March 2015 Dark energy camera snaps first images ahead of survey BBC 2012 09 18 The Dark Energy Survey begins Fermilab 2013 09 03 Survey Legacy 2012 11 08 The Dark Energy Camera Legacy Survey DECaLS Legacy Survey Retrieved 2023 12 31 a b Dey Arjun Schlegel David J Lang Dustin Blum Robert Burleigh Kaylan Fan Xiaohui Findlay Joseph R Finkbeiner Doug Herrera David Juneau Stephanie Landriau Martin Levi Michael McGreer Ian Meisner Aaron Myers Adam D 2019 05 01 Overview of the DESI Legacy Imaging Surveys The Astronomical Journal 157 5 168 arXiv 1804 08657 Bibcode 2019AJ 157 168D doi 10 3847 1538 3881 ab089d ISSN 0004 6256 Survey Legacy 2023 09 28 Data Release Description Legacy Survey Retrieved 2023 12 31 Schlafly E F Green G M Lang D Daylan T Finkbeiner D P Lee A Meisner A M Schlegel D Valdes F 2018 02 01 The DECam Plane Survey Optical Photometry of Two Billion Objects in the Southern Galactic Plane The Astrophysical Journal Supplement Series 234 2 39 arXiv 1710 01309 Bibcode 2018ApJS 234 39S doi 10 3847 1538 4365 aaa3e2 ISSN 0067 0049 Observations The Dark Energy Survey Survey and operations DES Collaboration Abbott T M C Abdalla F B Alarcon A Aleksic J Allam S Allen S Amara A Annis J Asorey J Avila S 2018 08 27 Dark Energy Survey Year 1 Results Cosmological Constraints from Galaxy Clustering and Weak Lensing Physical Review D 98 4 043526 arXiv 1708 01530 Bibcode 2018PhRvD 98d3526A doi 10 1103 PhysRevD 98 043526 ISSN 2470 0010 S2CID 52219057 Troxel M A MacCrann N Zuntz J Eifler T F Krause E Dodelson S Gruen D Blazek J Friedrich O Samuroff S Prat J 2018 08 27 Dark Energy Survey Year 1 Results Cosmological Constraints from Cosmic Shear Physical Review D 98 4 043528 arXiv 1708 01538 Bibcode 2018PhRvD 98d3528T doi 10 1103 PhysRevD 98 043528 ISSN 2470 0010 S2CID 52993521 Hoyle B Gruen D Bernstein G M Rau M M De Vicente J Hartley W G Gaztanaga E DeRose J Troxel M A Davis C Alarcon A 2018 07 21 Dark Energy Survey Year 1 Results Redshift distributions of the weak lensing source galaxies Monthly Notices of the Royal Astronomical Society 478 1 592 610 arXiv 1708 01532 doi 10 1093 mnras sty957 ISSN 0035 8711 Drlica Wagner A Sevilla Noarbe I Rykoff E S Gruendl R A Yanny B Tucker D L Hoyle B Rosell A Carnero Bernstein G M Bechtol K Becker M R 2018 04 03 Dark Energy Survey 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Rosell A Carnero Becker M R Drlica Wagner A Gruendl R A Rykoff E S Sheldon E Yanny B Alarcon A 2021 06 01 Dark Energy Survey Year 3 Results Photometric Data Set for Cosmology The Astrophysical Journal Supplement Series 254 2 24 arXiv 2011 03407 Bibcode 2021ApJS 254 24S doi 10 3847 1538 4365 abeb66 ISSN 0067 0049 S2CID 226278355 a b Jeffrey N Gatti M Chang C Whiteway L Demirbozan U Kovacs A Pollina G Bacon D Hamaus N Kacprzak T Lahav O 2021 06 25 Dark Energy Survey Year 3 results Curved sky weak lensing mass map reconstruction Monthly Notices of the Royal Astronomical Society 505 3 4626 4645 arXiv 2105 13539 doi 10 1093 mnras stab1495 ISSN 0035 8711 a b Castelvecchi Davide 2021 05 28 The most detailed 3D map of the Universe ever made Nature d41586 021 01466 1 doi 10 1038 d41586 021 01466 1 ISSN 0028 0836 PMID 34050347 S2CID 235242965 The Dark Energy Survey Science Program PDF Archived from the original PDF on 2011 07 20 Retrieved 2010 12 02 Mapping the cosmos Dark Energy Survey creates 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2014JASIS 65 1157L doi 10 1002 asi 23044 ISSN 2330 1635 S2CID 30584899 Brout D Scolnic D Kessler R D Andrea C B Davis T M Gupta R R Hinton S R Kim A G Lasker J Lidman C Macaulay E 2019 04 02 First Cosmology Results Using Type Ia Supernovae From the Dark Energy Survey Analysis Systematic Uncertainties and Validation The Astrophysical Journal 874 2 150 arXiv 1811 02377 doi 10 3847 1538 4357 ab08a0 ISSN 1538 4357 S2CID 119537585 Brout D Sako M Scolnic D Kessler R D Andrea C B Davis T M Hinton S R Kim A G Lasker J Macaulay E Moller A 2019 03 27 First Cosmology Results Using Type Ia Supernovae From the Dark Energy Survey Photometric Pipeline and Light Curve Data Release The Astrophysical Journal 874 1 106 arXiv 1811 02378 Bibcode 2019ApJ 874 106B doi 10 3847 1538 4357 ab06c1 ISSN 1538 4357 S2CID 102487487 Becker J C Khain T Hamilton S J Adams F C Gerdes D W Zullo L et al DES Collaboration 2018 Discovery and dynamical analysis of an extreme trans Neptunian object with a high orbital inclination The Astronomical Journal 156 2 81 arXiv 1805 05355 Bibcode 2018AJ 156 81B doi 10 3847 1538 3881 aad042 S2CID 55163842 JPL Small Body Database Browser ssd jpl nasa gov 2 451657 Chamberlin Alan JPL Small Body Database Browser ssd jpl nasa gov 2 471954 JPL Small Body Database Browser ssd jpl nasa gov 2 472262 JPL Small Body Database Browser ssd jpl nasa gov 2 483002 JPL Small Body Database Browser ssd jpl nasa gov 2 491767 JPL Small Body Database Browser ssd jpl nasa gov 2 491768 JPL Small Body Database Browser ssd jpl nasa gov 2 495189 JPL Small Body Database Browser ssd jpl nasa gov 2 495190 JPL Small Body Database Browser ssd jpl nasa gov 2 495297 Minor Planet Discoverers by number Minor Planet Center 15 November 2016 Retrieved 27 January 2017 Dark Energy Survey Releases Most Precise Look at the Universe s Evolution NOIRLab Press Release Retrieved 17 June 2021 External links editDark Energy Survey website Dark Energy Survey Science Program PDF Dark Energy Survey Data Management Dark Energy Camera DECam Archived 2017 10 18 at the Wayback Machine Biron Lauren 4 October 2022 15 spectacular photos from the Dark Energy Camera symmetry magazine Portals nbsp Astronomy nbsp Stars nbsp Spaceflight nbsp Outer space nbsp Solar System Retrieved from https en wikipedia org w index php title Dark Energy Survey amp oldid 1221801572 DECam, wikipedia, wiki, book, books, library,

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