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David James (CTIO) for the Dark Energy Survey Pan-STARRS1: Science Results STScI , Baltimore - 24 June 2014 PowerPoint PPT Presentation


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

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David James (CTIO) for the Dark Energy Survey Pan-STARRS1: Science Results STScI , Baltimore - 24 June 2014

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The Dark Energy Survey:

Dark Energy Camera – DES:

YR1 of the Dark Energy Survey

David James (CTIO)

for the Dark Energy Survey

Pan-STARRS1: Science Results

STScI, Baltimore - 24 June 2014


The Dark Energy Survey:

  • Survey project to probe signatures of

  • Dark Energy using four complementary

  • techniques:

    • Cluster Counts

    • Weak Lensing

    • Large-scale Structure

    • Supernovae

  • Two multiband surveys:

    • 5000 deg2: 10σgriz(Y) to 24th (21.6th) mag

    • 30 deg2: repeated SNe fields

  • Build new 3 deg2FoV camera

  • and data management system:

    • Survey 2013-2018 (525 nights)

    • Facility instrument for Blanco

Blanco 4-metre Telescope at CTIO

http://lsst.org

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

Pan-STARRS1: Science Results Dark Energy Survey David James


DarkEnergyCamera:

A new prime focus instrument

CCD

Readout

Filters +

Shutter

Focal plane (detector, 62+ CCDs)

Hexapod

Corrector

Lenses

Pan-STARRS1: Science Results Dark Energy Survey David James


Brave New World: DECam

Pan-STARRS1: Science Results Dark Energy Survey David James


Controlling DECam: SISPI

  • Data Flow:

    • Image acquisition (Panview, 6 Monsoon crates)

    • Image Builders (multiple instances)

      • FITS formatting

      • Image Health

      • Telemetry

      • Compression

    • Submit to NCSA (DTS)

  • Observation Control:

    • OCS (pipeline architecture)

    • OBSTAC

  • Instrument Control:

    • Internal (shutter, hexapod, filters)

    • External (cooling, temperatures, ICC)

  • Guider & Focus:

  • Interfaces to TCS & Cloud Camera:

SISPI is the DECamdata

acquisition and control system:

Pan-STARRS1: Science Results Dark Energy Survey David James


The Dark Energy Camera: Detector

2k x 2k

Focus &

Alignment

2k x 2k

Guide

2k x 2k

Focus &

Alignment

2k x 2k

Guide

Pan-STARRS1: Science Results Dark Energy Survey David James


2 tilings

3 tilings

(original) DES Observing Strategy:

  • Sept-Feb observing seasons

  • 80-100 sec exposures

  • 2 filters per pointing (typically)

    • grin dark time

    • izyin bright/grey time

  • Photometric calibration: overlap tilings, standard stars, spectrophotometric calibration system, preCAM

  • 2 survey tilings/filter/year

  • Interleave 10 SNe fields in griz if non-photometric or bad seeing or time gap (aim for ~5 day cadence)

Pan-STARRS1: Science Results Dark Energy Survey David James


(present) DES Observing Strategy:

Year 1 regions

SDSS Stripe 82

  • Year 1:

  • Moved footprint eastward to reduce secZ, improve image quality

  • Cover 2000 sq. deg. (4 tilings per filter) rather than full 5000 sq. deg. (2 tilings) to improve photometric calibration

  • Allow g, Y observations with seeing>1.1” (not used for Weak Lensing).

  • Year 2:

  • Complementary 3000 sq. deg.

  • Optimize: many more half-nights than YR1

SPT

By end of YR2, expect will have done 90% of the exposures needed to complete 4 tilings of the 5000 sq. deg. footprint.

Pan-STARRS1: Science Results Dark Energy Survey David James


Dark Energy Survey: Year 1

  • DES started taking YR1 data on Aug. 31st 2013

  • In January, we switched to 1st half nights

  • Finished YR1 in mid-February 2014

Pan-STARRS1: Science Results Dark Energy Survey David James


DES: Observing Sequences

Pan-STARRS1: Science Results Dark Energy Survey David James


Year 1 (vs. SVA1):

Exposure Breakdown

Pan-STARRS1: Science Results Dark Energy Survey David James


First DES YR1 Image

  • 31st Aug. 2013 23:55

    Local Chilean Time

  • Image DECam_00229250 was transferred to NCSA in Urbana where;

    • DES “Data Management” processed it and made a catalog of the stars and roughly 100,000 galaxies that can be identified in it.

First DES YR1 image is #229250

Pan-STARRS1: Science Results Dark Energy Survey David James


DES Operations EfficiencyMeasurements

  • Only 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.

  • The other problems are computer interfaces issues, … mostly, shutter resets

  • Shutter was open 63% of “Observing Time” during YR1. Dome control improvements gave us ~4% better efficiency starting in late December 2013.

Pan-STARRS1: Science Results Dark Energy Survey David James


DES WFSurvey

  • Goal was to observe 4 “tiles” of ~672 images per tile in each of 5 filters

  • 13435 images total

  • Plots here show what we obtained:

    • Gaps in Stripe 82 (North)

    • Gaps in Sept. to Nov. survey area (West)

    • Images 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


DES SN Survey: YR1 Observations

  • 10 SN fields. 2 of those are “deep fields”

  • Our plot shows day-by-day SNe cadence

  • 2565/2699 SNe exposures “good” (95%)

  • After 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


DES Observing: YR2

Pan-STARRS1: Science Results Dark Energy Survey David James


First DES (SV) Science Paper:

2014arXiv1405.4285M

Pan-STARRS1: Science Results Dark Energy Survey David James


Community Use of DECam:

  • DECam-NEOO:

    • Lori Allen (NOAO – PI)

    • 3-yr survey time awarded

    • 1st 10-night block executed April 2014

    • Early results are very encouraging

  • Light-echoes of SNe remnants:

    • Armin Rest (STSci– PI)

    • many nights per semester

    • étendue of DECam critical

    • latest results are now available: Prieto et al. 2014, ApJL, 787, L8

Pan-STARRS1: Science Results Dark Energy Survey David James


DECam Current Status

  • Sensor array is OK except

  • Two CCDs are no longer functioning correctly:

    • N30 11/07/2012

    • S30 11/28/2013

  • 8 CCDs ~12e- RO noise (7e- is typical), spec is 15 e-. Problem comes and goes since late Nov.

  • S7 (½ CCD) non-linearity unstable at very low light levels (<1000e-).

  • Two focus chips have 1 “weak” amplifier.

S30

S7

N30

Pan-STARRS1: Science Results Dark Energy Survey David James


The DES Collaboration

Thank you !

Pan-STARRS1: Science Results Dark Energy Survey David James


The DES Collaboration

Pan-STARRS1: Science Results Dark Energy Survey David James


The DES Collaboration

Pan-STARRS1: Science Results Dark Energy Survey David James


NOAO

NCSA

For details, ask Brian Yanny, DES Data Coordinator,

or Robert Gruendl, UIUC


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