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David James (CTIO) for the Dark Energy Survey Pan-STARRS1: Science Results STScI, Baltimore - 24 June 2014 Dark Energy Camera – DES: YR1 of the Dark Energy.

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Presentation on theme: "David James (CTIO) for the Dark Energy Survey Pan-STARRS1: Science Results STScI, Baltimore - 24 June 2014 Dark Energy Camera – DES: YR1 of the Dark Energy."— Presentation transcript:

1 David James (CTIO) for the Dark Energy Survey Pan-STARRS1: Science Results STScI, Baltimore - 24 June 2014 Dark Energy Camera – DES: YR1 of the Dark Energy Survey The Dark Energy Survey:

2 Pan-STARRS1: Science Results Dark Energy Survey David James The Dark Energy Survey: Blanco 4-metre Telescope at CTIO ΩSurvey project to probe signatures of Dark Energy using four complementary techniques: ΩCluster Counts ΩWeak Lensing ΩLarge-scale Structure ΩSupernovae ΩTwo multiband surveys: Ω5000 deg 2 : 10σ griz(Y) to 24 th (21.6 th ) mag Ω30 deg 2 : repeated SNe fields ΩBuild new 3 deg 2 FoV camera and data management system: ΩSurvey (525 nights) ΩFacility instrument for Blanco

3 Pan-STARRS1: Science Results Dark Energy Survey David James The DES Collaboration Fermilab University of Illinois at Urbana-Champaign/NCSA University of Chicago Lawrence Berkeley National Lab NOAO/CTIO DES Spain Consortium DES United Kingdom Consortium University of Michigan Ohio State University University of Pennsylvania DES Brazil Consortium Argonne National Laboratory SLAC-Stanford-Santa Cruz Consortium Universitats-Sternwarte Munchen Texas A&M University plus Associate members at: Brookhaven National Lab, U. North Dakota, Paris, Taiwan Several hundred members plus students & postdocs Funding: DOE, NSF; UK: STFC, SRIF; Spain Ministry of Science, Brazil: FINEP, Ministry of Science, FAPERJ; Germany: Excellence Cluster; collaborating institutions

4 Pan-STARRS1: Science Results Dark Energy Survey David James Dark Energy Camera: A new prime focus instrument Hexapod Corrector Lenses CCD Readout Filters + Shutter Focal plane (detector, 62+ CCDs)

5 Pan-STARRS1: Science Results Dark Energy Survey David James Brave New World: DECam ParameterMosaic IIDECam No. of CCDs (F&A, guiding) CCD Format2Kx4K, 15μ pixels CCD TypeStandard, BBARDepleted, red optimized Full well60K130K Image size128 MB1040 MB RON6-12 e- rms15 e- rms Read time100s17s Overheads10s3s GuidingseparateFocal plane Filtersmanyg r i z Y ADCyesno

6 Pan-STARRS1: Science Results Dark Energy Survey David James Controlling DECam: SISPI ΩData Flow: ΩImage acquisition (Panview, 6 Monsoon crates) ΩImage Builders (multiple instances) ΩFITS formatting ΩImage Health ΩTelemetry ΩCompression ΩSubmit to NCSA (DTS) ΩObservation Control: ΩOCS (pipeline architecture) ΩOBSTAC ΩInstrument Control: ΩInternal (shutter, hexapod, filters) ΩExternal (cooling, temperatures, ICC) ΩGuider & Focus: ΩInterfaces to TCS & Cloud Camera: SISPI is the DECam data acquisition and control system:

7 Pan-STARRS1: Science Results Dark Energy Survey David James The Dark Energy Camera: Detector 2k x 2k Guide 2k x 2k Focus & Alignment 2k x 2k Focus & Alignment 2k x 2k Guide

8 Pan-STARRS1: Science Results Dark Energy Survey David James (original) DES Observing Strategy: 2 tilings 3 tilings ΩSept-Feb observing seasons Ω sec exposures Ω2 filters per pointing (typically) Ωgr in dark time Ωizy in bright/grey time ΩPhotometric calibration: overlap tilings, standard stars, spectrophotometric calibration system, preCAM Ω2 survey tilings/filter/year ΩInterleave 10 SNe fields in griz if non-photometric or bad seeing or time gap (aim for ~5 day cadence)

9 Pan-STARRS1: Science Results Dark Energy Survey David James (present) DES Observing Strategy: Year 1 regions SDSS Stripe 82 SPT Year 1: ΩMoved footprint eastward to reduce secZ, improve image quality ΩCover 2000 sq. deg. (4 tilings per filter) rather than full 5000 sq. deg. (2 tilings) to improve photometric calibration ΩAllow g, Y observations with seeing>1.1” (not used for Weak Lensing). Year 2: ΩComplementary 3000 sq. deg. ΩOptimize: many more half-nights than YR1 By end of YR2, expect will have done 90% of the exposures needed to complete 4 tilings of the 5000 sq. deg. footprint.

10 Pan-STARRS1: Science Results Dark Energy Survey David James Dark Energy Survey: Year 1 Month# Full Nights# 1 st Half Nights # 2 nd Half Nights August100 September2400 October1400 November1800 December2700 January4190 February090 ΩDES started taking YR1 data on Aug. 31 st 2013 ΩIn January, we switched to 1 st half nights ΩFinished YR1 in mid-February 2014

11 Pan-STARRS1: Science Results Dark Energy Survey David James DES: Observing Sequences

12 Pan-STARRS1: Science Results Dark Energy Survey David James Year 1 (vs. SVA1): Exposure Breakdown SVA1YEAR1 Time period11/01/12 − 02/15/1308/31/13 − 02/15/14 # exposures % accepted # exposures% accepted All bands10929*60%17605*82% g199858% % r208653% % i228157% % z237565% % Y160888% %

13 First DES YR1 Image First DES YR1 image is # ΩImage DECam_ was transferred to NCSA in Urbana where; ΩDES “Data Management” processed it and made a catalog of the stars and roughly 100,000 galaxies that can be identified in it. 31 st Aug :55 Local Chilean Time Pan-STARRS1: Science Results Dark Energy Survey David James

14 ΩOnly 2 problems lasted as long as 4 consecutive hours: In Oct. we lost a night from a TCS software bug. In Nov. we lost 1½ nights due to problems w/ electronics: noise and missing backplanes, then CCD S30 failed. ΩThe other problems are computer interfaces issues, … mostly, shutter resets ΩShutter was open 63% of “Observing Time” during YR1. Dome control improvements gave us ~4% better efficiency starting in late December DES Operations Efficiency Measurements OperationDES Yr. 1 Accumulated Hrs. (%) DES Extended SV Hrs. (%) Observing Time Available888.25(100)321.0(100) Observing Time751.50(84.6)226.7(70.6) Engineering ObservationsNA23.2(7.2) Bad Weather90.25(10.2)24.5(7.6) Telescope or Infrastructure Failure => can’t observe 18(2.0)45.1(14.1) Camera Systems Failure => can’t observe 25.75(2.9)1.5(0.5) Observer Error2.75(0.3)0(0.0) Pan-STARRS1: Science Results Dark Energy Survey David James

15 DES WF Survey ΩGoal was to observe 4 “tiles” of ~672 images per tile in each of 5 filters Ω13435 images total ΩPlots here show what we obtained: ΩGaps in Stripe 82 (North) ΩGaps in Sept. to Nov. survey area (West) ΩImages in YR2 fields because nothing “available” from YR1 particularly in late Jan. to Feb. ~3k images (17%) of YR2 Pan-STARRS1: Science Results Dark Energy Survey David James

16 DES SN Survey: YR1 Observations Ω10 SN fields. 2 of those are “deep fields” ΩOur plot shows day-by- day SNe cadence Ω2565/2699 SNe exposures “good” (95%) ΩAfter 7-days, even when the weather is good, SNe team gets their data on “deadman” condition of OBSTAC. Pan-STARRS1: Science Results Dark Energy Survey David James

17 DES Observing: YR2

18 Pan-STARRS1: Science Results Dark Energy Survey David James First DES (SV) Science Paper: 2014arXiv M

19 Pan-STARRS1: Science Results Dark Energy Survey David James Community Use of DECam: ΩDECam-NEOO: ΩLori Allen (NOAO – PI) Ω3-yr survey time awarded Ω1 st 10-night block executed April 2014 ΩEarly results are very encouraging ΩLight-echoes of SNe remnants : ΩArmin Rest (STSci – PI) Ωmany nights per semester Ωétendue of DECam critical Ωlatest results are now available: Prieto et al. 2014, ApJL, 787, L8

20 DECam Current Status Ω Sensor array is OK except Ω Two CCDs are no longer functioning correctly: Ω N30 11/07/2012 Ω S30 11/28/2013 Ω 8 CCDs ~12e - RO noise (7e - is typical), spec is 15 e -. Problem comes and goes since late Nov. Ω S7 (½ CCD) non-linearity unstable at very low light levels (<1000e - ). Ω Two focus chips have 1 “weak” amplifier. S30 N30 S7 Pan-STARRS1: Science Results Dark Energy Survey David James

21 The DES Collaboration Thank you !

22 Pan-STARRS1: Science Results Dark Energy Survey David James The DES Collaboration

23 Pan-STARRS1: Science Results Dark Energy Survey David James The DES Collaboration

24 DECam Community Workshop, Tucson, August NOAO NCSA For details, ask Brian Yanny, DES Data Coordinator, or Robert Gruendl, UIUC

25 DECam Community Workshop, Tucson, August


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