. Quentin Parker (AAO/MQ) on behalf of Stefan Keller, Brian Schmidt and Mike Bessell (ANU) SkyMapper and prospects for narrow-band Imaging surveys of the Southern Galactic plane EGAPS meeting Tenerife Jan 2009

What is SkyMapper?  1.35m robotic telescope with a 5.7 sq. degree field  Sited at Siding Spring Observatory, NSW  Will conduct a multi colour, multi epoch Stromlo Southern Sky Survey  Is a “replacement” for the 50inch Great Melbourne Telescope that was destroyed  EGAPS meeting Tenerife Jan 2009 SkyMapper will measure the brightness and positions of around a billion stars across the southern sky to unprecedented accuracy.

Skymapper! EGAPS meeting Tenerife Jan 2009 early 2009

Why a SkyMapper?  There is currently no deep digital optical map of the southern sky  no instrument is planned that can map the entire southern sky in multiple colours and epochs  SkyMapper will provide an automated large-scale imaging capability that is well matched to:  Australian science strengths;  Instrumentation (AAOmega, Gemini access etc.), and;  Conditions – “poor seeing” a benefit  cover the sky faster! EGAPS meeting Tenerife Jan 2009

Overview  SkyMapper designed and led by the ANU in Australia  It is a $12.5M investment by the ANU  It will be amongst the first of a new generation of rapid survey telescopes with high cadence  We are entering a new age where survey telescopes such as VST, VISTA and SKymapper will lead to the generation of wide-field hemispheric multi-epoch digital surveys ⇒ of massive size! (Peta byte)  SkyMapper will give us the ability to dissect the Galaxy and understand its structure and formation EGAPS meeting Tenerife Jan 2009

The coming data deluge… EGAPS meeting Tenerife Jan 2009

Skymapper Collaboration Policy  Is a set procedure for non-ANU parties to gain access to general survey data during data characterisation period of approx. 18 months before First Data Release including establishing an MoU and authorship policy  Access to non-survey observing time (25%) is restricted to ANU applicants and agreed collaborators.  External parties will require a primary investigator [PI] within the ANU and the PI should devote a substantial amount of time to the program.  Both Stefan Keller/Mike Bessell will lead the H-alpha programme inititally – scope for MQ, VPHAS+ team involvement EGAPS meeting Tenerife Jan 2009

The installed Skymapper EGAPS meeting Tenerife Jan 2009

The SkyMapper instrument  Designed by RSAA  32 4x2k CCDs  Off-Axis Guider  Shack-Hartmann feed  Cooled with closed cycle cryogenic system  6 filter slots (note narrow-band surveys will require a manual filter wheel change –not automatic)  StarGrasp controller for CCD readout EGAPS meeting Tenerife Jan 2009

CCD performance  ~15s readout time  5e- readnoise  e- full well capacity  linearity to 0.5%  QE > 60% ( nm), QE > 20% ( nm)  Shutter Accuracy: 1% on 1second exposure  0.5arcsecond pixels EGAPS meeting Tenerife Jan 2009

The Skymapper CCDs EGAPS meeting Tenerife Jan 2009 UKST could cover maximum of 11x40sq.deg/night 0.5 arcsec pixels

The Stromlo Southern Sky Survey Basic characteristics  Multi-colour, multi-epoch of all 20,000 sq. degrees south of equator (ugriz filter + stromgren-like v)  Data supplied to the community via Virtual Observatory  Star and Galaxy photometry (3% absolute calibration)  Astrometry to better than 50 mas  Digital images available for download photometrically calibrated  Accurate World Coordinate Systems for single images and combined images.  Cadence: 0, +4 hours, +2-3 days, +1-2 weeks and +1-2 years  Five years to complete  Is thus complementary to the SDSS but with improvements EGAPS meeting Tenerife Jan 2009

Cadence and Coverage  SkyMapper will be the fastest imaging survey telescope (to similar sky depth) in the world  Comes on line in early  Will allow astronomers to perform massive studies requiring large sky coverage quickly and efficiently.  SkyMapper is the only survey telescope of this calibre in the southern hemisphere, providing a unique advantage. EGAPS meeting Tenerife Jan 2009

Skymapper Data Products  Deliverables to the Outside User:  Data (epoch, RA, DEC, mags, galaxy shape info,…) to be available through a web-served interface which provides catalogs over a user defined area  Images to be available through a web-served interface which provides images over a user defined area (maximum size will be limited)  Narrow bad survey data access may be different EGAPS meeting Tenerife Jan 2009

Skymapper Data Products How Much Data??? 6 epochs x 6 colours x 4000 x 268,000,000 pixel images =150 Terabytes + 25 Terabytes of calibration images  1 Billion Objects observed 36 times to provide a database that is ~2 Terabytes in size (1 billion rows x 500 columns) We intend to supplement these data in selected regions such as the Galactic Plane with H-alpha images and later other narrow-band images making use of the 30% of Skymapper time not dedicated to the prime surveys EGAPS meeting Tenerife Jan 2009

Survey data will:  Provide a Galactic census of temperature gravity, metallicity and variability for ~5 billion stars   the assembly and chemical enrichment history of the bulge, thin/thick disk and halo  Provide a digital reference for radio, X-ray and GRB instruments  Uncover extremely metal poor stars  Uncover new dwarf galaxy members of the local group  Discover large numbers of SNe  Provide accurate photometric calibration of galaxy redshift surveys: 2dF/6dF.  Discover bright QSOs including those with Z>6   probes of the ionization history of the Universe.   variability and evolution EGAPS meeting Tenerife Jan 2009

Non survey science identified  Planet Transit studies  Microlensing Studies  Mapping Supernovae  Widefield surveys in non-survey filters with the initial priority being H-alpha  Narrow-band survey would start shortly after main surveys EGAPS meeting Tenerife Jan 2009

Main SkyMapper filter set  A specially designed set of optical filters are placed in front of the camera to select the colour of light recorded.  The innovative filter set provides unparalleled determination of the fundamental stellar parameters:  temperature, density and heavy element abundance. EGAPS meeting Tenerife Jan 2009

Broad-band SkyMapper Filter Set Ex-atmosphere EGAPS meeting Tenerife Jan 2009

Expected Skymapper limits (1.5" seeing) for signal-to-noise of 5 in AB mags uvsvs griz 1 epoch expt. time110 6 epochs Sloan Digital Sky Survey comparison 22.0n/a EGAPS meeting Tenerife Jan 2009 The Stromlo Southern Sky Survey will go around a magnitude fainter than the DSS

Rapid Survey era is emerging… EGAPS meeting Tenerife Jan

Possible H-alpha survey(s)  Approximately 75% of the time on SkyMapper will be initially dedicated to the Southern Sky Survey.  This leaves 25% for other projects including a H-alpha survey that can make effective use of BoM.  Proposed 120sec H-alpha exposures with 25sec readout and 5.7sq.deg/exposure  1296 sq/deg/night.  SkyMapper has LGP of UKST.  Entire 4000sq.deg of SHS covered in 3.1 nights but ~1mag shallower or 24 nights to ~same depth with 15min exposures  SkyMapper pixel size 0.5arcsec (cf SCOS 0.67arcsec) EGAPS meeting Tenerife Jan 2009

EGAPS WORKSHOP SEP

Swinburne September 13th 2007 SuperCosmos H-alpha Survey (SHS):

We are in the South! EGAPS meeting Tenerife Jan 2009

Narrow band SkyMapper filters  Originally planned to re-use the AAO/UKST monolithic H- alpha filter (worth $46K in today’s money)  Unfortunately re-designs to filter wheel meant that the AAO/UKST filter would no longer fit into the required enclosure  New H-alpha filter will be required and various options have been discussed (Mike Bessell)  Decision made in March 2009 but will come from ANU funds with possible addition from MQ  Additional narrow-band filters such as [OIII] and [SII] will be the subject of a LIEF bid led in May 2009 by ANU but with MQ/VPHAS+ participation (and possibly others) EGAPS meeting Tenerife Jan 2009

Proposed H-alpha filter EGAPS meeting Tenerife Jan 2009

Building on the main Skymapper surveys  As with IPHAS, but with the added advantage of multi-epoch observations, the r and I band images can be combined with the H-alpha (and possibly other narrow-band images later) to provide powerful discrimination for point-source emitters.  Multi-epoch observations permit elimination of variables EGAPS meeting Tenerife Jan 2009

Tangible community benefits  The H-alpha filter will be available to any user of the SkyMapper telescope.  This will allow a wider range of science to be conducted by the telescope, thereby increasing its user-base and scientific impact.  The analysis of H-alpha data will be incorporated into a program to provide research experience for undergraduates.  This program will assist in the retention of students to higher degree programs by engaging them in cutting edge science.  The H-alpha filter will expedite the PhD thesis of Mr. Simon Murphy and form the basis of numerous theses in the future. It will facilitate Australian (Prof. Q. Parker, Macquarie University, Dr. M. Filopovic, Univ. Wollongong, Prof. A. Green, Univ. Sydney) and international (Prof. J. Drew, Imperial UK) collaborations with RSAA academics. EGAPS meeting Tenerife Jan 2009

H-alpha survey cost effectiveness: leverage on SkyMapper investment  The proposed filter enables us to probe a specific region of the stellar spectrum for hundreds of thousands of stars in a single exposure.  The alternative, obtaining a spectrum for each star, is simply not feasible.  The H-alpha filter will turn SkyMapper into an efficient tool for locating these extremely rare glimpses into stellar birth and death across the southern sky. EGAPS meeting Tenerife Jan 2009

Skymapper H-alpha data  The SkyMapper H-alpha filter will adds an additional dimension to the current SkyMapper program  it opens up the study of the gas phase building on the success of the AAO/UKST H-alpha survey in the South  The H-alpha data obtained together with the SkyMapper survey data  It is intended to make the H-alpha data available to the world via the web after data validation and perhaps some preliminary exploitation (TBC)  This develops an additional powerful data resource of benefit to the national and international communities EGAPS meeting Tenerife Jan 2009

Conclusions EGAPS meeting Tenerife Jan 2009

Possible H-alpha survey(s)  Approximately 75% of the time on SkyMapper will be initially dedicated to the Southern Sky Survey.  This leaves 25% for other projects including a H-alpha survey that can make effective use of BoM.  Proposed 120sec H-alpha exposures with 25sec readout and 5.7sq.deg/exposure  1296 sq/deg/night.  SkyMapper has LGP of UKST.  Assume CCD ~10xDQE of tech-pan film and filter of same quality and throughput  x7.67 slower  ~1.1mag less deep  Entire 4000sq.deg of SHS covered in 3.1 nights but ~1mag shallower or 24 nights to ~same depth with 15min exposures  SkyMapper pixel size 0.5arcsec (cf SCOS 0.67arcsec) EGAPS meeting Tenerife Jan 2009

Additional short ‘5-second’ survey  Will be undertaken in photometric conditions  Used for calibration of stars from 9-16th magnitude in all bands  Will provide the calibration of the survey and will allow the survey to be tied to the Hipparchos and Tycho catalogs (and other photometric standard systems that are established in the southern hemisphere)  Will ensure uniformity across the sky. EGAPS meeting Tenerife Jan 2009

Survey Science The survey science questions are broad and include:  What is the distribution of large Solar-System objects beyond Neptune?  What is the history of the youngest stars in the Solar neighbourhood?  How far does the dark matter halo of our galaxy extend and what is its shape?  What is the detailed structure of our Galaxy and Magellanic clouds? EGAPS meeting Tenerife Jan 2009