ANU Skymapper
Permanent URI for this collectionhttps://hdl.handle.net/1885/122898
Constructed and operated by The Australian National University's Research School of Astronomy and Astrophysics, SkyMapper is a state-of-the-art, wide-field survey telescope that represents a new vehicle for astronomical discovery in Australia. Situated under the clear, dark skies of Siding Spring Observatory near Coonabarabran in central NSW, SkyMapper's mission is to create the first comprehensive digital survey of the entire southern sky. The result will be a massively detailed record of more than a billion stars and galaxies, to a sensitivity one million times fainter than the human eye can see.
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Item Metadata only SkyMapper's Southern Sky Survey : Early Data Release (EDR)(Canberra, ACT : The Australian National University) Wolf, Christian; Onken, Christopher; Luvaul, Lance; Schmidt, Brian; Bessell, Michael; Chang, Seo-Won; Da Costa, Gary; Mackey, Dougal; Murphy, Simon; Shao, Li; Smillie, Jon; White, MarcThe SkyMapper Early Data Release (EDR) is the initial data release from the SkyMapper Southern Survey, which aims to create a deep, multi-epoch, multi-band photometric data set for the entire southern sky. EDR covers approximately 6700 sq. deg. (one-third) of the southern sky as obtained by the Short Survey component of the project. All included fields have at least two visits in good conditions in all six SkyMapper filters (uvgriz). Object catalogues are complete to magnitude 17-18, depending on filter. IVOA-complaint table access protocol (TAP), cone search and simple image access protocol (SIAP) services are available from the SkyMapper website (http://skymapper.anu.edu.au/), as well as through tools such as TOPCAT. Data are restricted to Australian astronomers and their collaborators for twelve months from the release date. Further details on the reduction of SkyMapper data, along with data quality improvements, will be released in late 2016 as part of SkyMapper Data Release 1 (DR1)Item Open Access The EMBLA Survey -- Metal-poor stars in the Galactic bulge(Oxford University Press on behalf of the Royal Astronomical Society, 2016-04-29) Howes, Louise M.; Asplund, Martin; Keller, Stefan C.; Casey, Andrew R.; Yong, David; Lind, Karin; Frebel, Anna; Hays, Austin; Alves-Brito, Alan; Bessell, Michael S.; Casagrande, Luca; Marino, Anna F.; Nataf, David M.; Owen, Christopher I.; Da Costa, Gary; Schmidt, Brian; Tisserand, PatrickCosmological models predict the oldest stars in the Galaxy should be found closest to the centre of the potential well, in the bulge. The EMBLA Survey successfully searched for these old, metal-poor stars by making use of the distinctive SkyMapper photometric filters to discover candidate metal-poor stars in the bulge. Their metal-poor nature was then confirmed using the AAOmega spectrograph on the AAT. Here we present an abundance analysis of 10 bulge stars with -2.8<[Fe/H]<-1.7 from MIKE/Magellan observations, in total determining the abundances of 22 elements. Combining these results with our previous high-resolution data taken as part of the Gaia-ESO Survey, we have started to put together a picture of the chemical and kinematic nature of the most metal-poor stars in the bulge. The currently available kinematic data is consistent with the stars belonging to the bulge, although more accurate measurements are needed to constrain the stars' orbits. The chemistry of these bulge stars deviates from that found in halo stars of the same metallicity. Two notable differences are the absence of carbon-enhanced metal-poor bulge stars, and the alpha-element abundances exhibit a large intrinsic scatter and include stars which are underabundant in these typically enhanced elements.Item Open Access Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way(Macmillan, 2015-11-26) Howes, L. M.; Casey, A. R.; Asplund, M.; Keller, S. C.; Yong, D.; Nataf, D. M.; Poleski, R.; Lind, K.; Kobayashi, C.; Owen, C. I.; Ness, M.; Bessell, M. S.; Da Costa, Gary; Schmidt, Brian; Tisserand, Patrick; Udalski, A.; Szymański, M. K.; Soszyński, I.; Pietrzyński, G.; Ulaczyk, K.; Wyrzykowski, Ł.; Pietrukowicz, P.; Skowron, J.; Kozłowski, S.; Mróz, P.The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than helium ('metals') have been found in the outer regions ('halo') of the Milky Way. The first stars and their immediate successors should, however, preferentially be found today in the central regions ('bulges') of galaxies, because they formed in the largest over-densities that grew gravitationally with time. The Milky Way bulge underwent a rapid chemical enrichment during the first 1-2 billion years, leading to a dearth of early, metal-poor stars. Here we report observations of extremely metal-poor stars in the Milky Way bulge, including one star with an iron abundance about 10,000 times lower than the solar value without noticeable carbon enhancement. We confirm that most of the metal-poor bulge stars are on tight orbits around the Galactic Centre, rather than being halo stars passing through the bulge, as expected for stars formed at redshifts greater than 15. Their chemical compositions are in general similar to typical halo stars of the same metallicity although intriguing differences exist, including lower abundances of carbon.Item Open Access The Extragalactic Distance Scale without Cepheids. IV.(2011-05-06) Hislop, Lachlan; Mould, Jeremy; Schmidt, Brian; Bessell, Michael S.; Da Costa, Gary; Francis, Paul; Keller, Stefan; Tisserand, Patrick; Rapoport, Sharon; Casey, AndyThe Cepheid period–luminosity relation is the primary distance indicator used in most determinations of the Hubble constant. The tip of the red giant branch (TRGB) is an alternative basis. Using the new Australian National University (ANU) SkyMapper Telescope, we calibrate the Tully–Fisher relation in the I band. We find that the TRGB and Cepheid distance scales are consistent.Item Open Access SkyMapper Filter Set: Design and Fabrication of Large Scale Optical Filters(2011-06-08) Bessell, Michael; Bloxham, Gabe; Schmidt, Brian; Keller, Stefan; Tisserand, Patrick; Francis, PaulThe SkyMapper Southern Sky Survey will be conducted from Siding Spring Observatory with u, v, g, r, i and z filters that comprise glued glass combination filters of dimension 309x309x15 mm. In this paper we discuss the rationale for our bandpasses and physical characteristics of the filter set. The u, v, g and z filters are entirely glass filters which provide highly uniform band passes across the complete filter aperture. The i filter uses glass with a short-wave pass coating, and the r filter is a complete dielectric filter. We describe the process by which the filters were constructed, including the processes used to obtain uniform dielectric coatings and optimized narrow band anti-reflection coatings, as well as the technique of gluing the large glass pieces together after coating using UV transparent epoxy cement. The measured passbands including extinction and CCD QE are presented.Item Metadata only The Stromlo Missing Satellites Survey(Springer Science+Business Media B.V.) Jerjen, HelmutAccording to cosmological theory, density fluctuations of Cold Dark Matter (CDM) form the first structures in the Universe. The gravitational potential wells of these dark matter halos suck in primordial gas and provide the seeds for the formation of stars via energy dissipation and cooling, a billion years after the Big Bang. The observational Universe today is filled with these galaxies, the prime repositories of shining baryonic matter. For obvious reasons, most of the detected and catalogued galaxies are intrinsically the largest and the brightest, those that can be seen from the greatest distance and are most easily studied against the night sky. Ironically, a major limitation on our ability to develop a consistent model that describes how galaxies emerged out of dark matter comes from the incompleteness of our picture of the nearby universe, in particular from the lack of a detailed understanding of the phenomenon dwarf galaxies.Item Open Access The SkyMapper Transient Survey(2017-02-18) Scalzo, Richard; Yuan, Fang; Childress, Michael J.; Moller, Anais; Schmidt, Brian; Tucker, Brad E.; Zhang, Bonnie; Astier, Pierre; Betoule, Marc; Regnault, NicolasThe SkyMapper 1.3 m telescope at Siding Spring Observatory has now begun regular operations. Alongside the Southern Sky Survey, a comprehensive digital survey of the entire southern sky, SkyMapper will carry out a search for supernovae and other transients. The search strategy, covering a total footprint area of ~2000 deg2 with a cadence of $\leq 5$ days, is optimised for discovery and follow-up of low-redshift type Ia supernovae to constrain cosmic expansion and peculiar velocities. We describe the search operations and infrastructure, including a parallelised software pipeline to discover variable objects in difference imaging; simulations of the performance of the survey over its lifetime; public access to discovered transients; and some first results from the Science Verification data.Item Metadata only SkyMapper Main Survey(Canberra, ACT : The Australian National University) Wolf, Christian; Onken, Christopher; Luvaul, Lance; Schmidt, Brian; Bessell, Michael; Chang, Seo-Won; Da Costa, Gary; Mackey, Dougal; Murphy, Simon; Shao, Li; Smillie, Jon; White, MarcMost of SkyMapper's observing time is now dedicated to the Main Survey. The survey scheduler aims to finish a field mostly within one moon period. A first visit in dark conditions establishes a colour sequence with all six bands observed in the space of 20 minutes. Further visits in subsequent nights under dark or grey sky conditions add exposure pairs in g- and r-band, while in grey or bright conditions pairs in i- and z-band are added. A second colour sequence in dark conditions finishes the set. Further pairs in i- and z-band are also observed during astronomical twilight. These twilight observations may be separated by many months from the night-time visits.Item Metadata only SkyMapper Shallow Survey(Canberra, ACT : The Australian National University) Wolf, Christian; Onken, Christopher; Luvaul, Lance; Schmidt, Brian; Bessell, Michael; Chang, Seo-Won; Da Costa, Gary; Mackey, Dougal; Murphy, Simon; Shao, Li; Smillie, Jon; White, MarcThe Shallow Survey was undertaken mostly in the first year of operations and continues during full moon periods. Each visit measures objects from 9 to 17 mag in all six bands. It provides the overall calibration of the Southern Sky Survey and allows the survey to be tied to the Hipparcos and Tycho catalogs (and other photometric systems established in the southern hemisphere, such as APASS). The Main Survey will be calibrated from Shallow Survey observations of spectrophotometric standards.Item Metadata only SkyMapper's Southern Sky Survey : First Data Release (DR1)(Canberra, ACT : The Australian National University) Wolf, Christian; Onken, Christopher; Luvaul, Lance; Schmidt, Brian; Bessell, Michael; Chang, Seo-Won; Da Costa, Gary; Mackey, Dougal; Murphy, Simon; Shao, Li; Smillie, Jon; White, MarcThe SkyMapper First Data Release provides data from the Shallow Survey across >98% of the southern sky, mostly covering the range from the South Celestial Pole to +2 deg in declination, with some extra coverage reaching +10 deg. Included are fields observed between March 2014 and September 2015, with a number of quality cuts applied. Each visit to a given field includes an exposure in all six filters, uvgriz, although on some fields (12%) not all filter images passed the quality cuts. Measurements from over 2.3 billion detections covering over 20,200 deg2 of sky are available. They correspond to ~300 million unique astrophysical objects from magnitude 8 to 18 (complete to ~17.5 mag, depending on the filter). All magnitudes reported on this site are AB mags.Item Open Access High-Resolution Spectroscopic Study of Extremely Metal-Poor Star Candidates from the SkyMapper Survey(IOP Publishing, 2015) Jacobson, Heather; Keller, Stefan; Frebel, Anna; Casey, Andrew; Asplund, Martin; Bessell, Michael; Da Costa, Gary; Lind, K; Marino, Anna; Norris, John; Peña, Jose M.; Schmidt, Brian; Tisserand, Patrick; Walsh, Jennifer M.; Yong, David; Yu, QinsiThe SkyMapper Southern Sky Survey is carrying out a search for the most metal-poor stars in the Galaxy. It identifies candidates by way of its unique filter set which allows for estimation of stellar atmospheric parameters. The set includes a narrow filter centered on the Ca ii K 3933 line, enabling a robust estimate of stellar metallicity. Promising candidates are then confirmed with spectroscopy. We present the analysis of Magellan Inamori Kyocera Echelle high-resolution spectroscopy of 122 metal-poor stars found by SkyMapper in the first two years of commissioning observations. Forty-one stars have . Nine have , with three at . A 1D LTE abundance analysis of the elements Li, C, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Sr, Ba, and Eu shows these stars have [X/Fe] ratios typical of other halo stars. One star with low [X/Fe] values appears to be "Fe-enhanced," while another star has an extremely large [Sr/Ba] ratio: Only one other star is known to have a comparable value. Seven stars are "CEMP-no" stars (, ). 21 stars exhibit mild r-process element enhancements (), while four stars have . These results demonstrate the ability to identify extremely metal-poor stars from SkyMapper photometry, pointing to increased sample sizes and a better characterization of the metal-poor tail of the halo metallicity distribution function in the future.Item Embargo Galaxies on Sub-Galactic Scales(CSLI Publications, 2012) Jerjen, HelmutThe Sloan Digital Sky Survey has been immensely successful in detecting new Milky Way satellite galaxies over the past seven years. It was instrumental in finding examples of the least luminous galaxies we know in the Universe, uncovering apparent inconsistencies between cold dark matter theory and dwarf galaxy properties, providing first evidence for a possible lower mass limit for dark matter halos in visible galaxies, and reopening the discussion about the building block scenario for the Milky Way halo. Nonetheless, these results are still drawn only from a relatively small number of galaxies distributed over an area covering about 29% of the sky, which leaves us currently with more questions than answers. The study of these extreme stellar systems is a multi-parameter problem: ages, metallicities, star formation histories, dark matter contents, population fractions and spatial distributions must be determined. Progress in the field is discussed and attention drawn to some of the limitations that currently hamper our ability to fully understand the phenomenon of the 'ultra-faint dwarf galaxy'. In this context, the Stromlo Milky Way Satellite Survey represents a new initiative to systematically search and scrutinize optically elusive Milky Way satellite galaxies in the Southern hemisphere. In doing so, the program aims at investigating some of the challenging questions in stellar evolution, galaxy formation and near-field cosmology.Item Open Access Probing the stellar halo of the milky way with the SEKBO RR Lyrae survey(IOP Publishing, 2012) Akhter, Shaila; Da Costa, Gary; Keller, Stefan; Schmidt, BrianWe investigate the steepening of the power-law slope beyond the Galactocentric radius of R ∼ 45kpc in the RR Lyrae (RRL) space density distribution found by Keller et al. They identified 2016 RRL candidates derived from the analysis of archival observatItem Open Access Implementation of the software systems for the SkyMapper automated survey telescope(SPIE -Society of Photo-optical Instrumentation Engineers, 2008) Vaccarella, Annino; Preston, Timothy; Czezowski, Adam; Keller, Stefan; Schmidt, Brian; Young, PeterThis paper describes the software systems implemented for the wide-field, automated survey telescope, SkyMapper. The telescope is expected to operate completely unmanned and in an environment where failures will remain unattended for several days. Failure analysis was undertaken and the control system extended to cope with subsystem failures, protecting vulnerable detectors and electronics from damage. The data acquisition and control software acquires and stores 512 MB of image data every twenty seconds. As a consequence of the short duty cycle, the preparation of the hardware subsystems for the successive images is undertaken in parallel with the imager readout. A science data pipeline will catalogue objects in the images to produce the Southern Sky Survey.Item Embargo Detailed element abundances of SkyMapper EMP stars: first results of the high-resolution spectroscopic follow up(Societa Astronomica Italiana, 2014) Jacobson, Heather; Asplund, Martin; Bessell, Michael; Casey, Andrew; Da Costa, Gary; Frebel, Anna; Keller, Stefan; Lind, K.; Norris, John; Schmidt, Brian; Tisserand, Patrick; Yong, DavidItem Embargo The SkyMapper Transit Survey(Conference Organising Committee, 2007) Bayliss, Daniel; Sackett, PennyItem Open Access The SkyMapper Southern Sky Survey(Astronomical Society of the Pacific, 2007) Keller, Stefan; Bessell, Michael; Schmidt, Brian; Francis, PaulItem Open Access Finding RR Lyrae Stars with SkyMapper: An Observational Test(Commonwealth Scientific and Industrial Research Organization Publishing, 2013) Akhter, Shaila; Da Costa, Gary; Keller, Stefan; Schmidt, Brian; Bessell, Michael; Tisserand, PatrickOne of the major science goals of the SkyMapper survey of the Southern Hemisphere sky is the determination of the shape and extent of the halo of the Galaxy. In this paper, we quantify the likely efficiency and completeness of the survey as regards the detection of RR Lyrae variable stars, which are excellent tracers of the halo stellar population. We have accomplished this via observations of the RR Lyrae-rich globular cluster NGC 3201. We find that for single-epoch uvgri observations followed by two further epochs of g, r imaging, as per the intended three-epoch survey strategy, we recover known RR Lyraes with a completeness exceeding 90%. We also investigate boundaries in the gravity-sensitive single-epoch two-colour diagram that yield high completeness and high efficiency (i.e., minimal contamination by non-RR Lyraes) and the general usefulness of this diagram in separating populations.Item Embargo The Stromlo Missing Satellites Survey(Springer Science + Business Media, 2008) Jerjen, HelmutItem Open Access The Gaia-ESO survey: the most metal-poor stars in the Galactic bulge(Oxford University Press, 2014-09-29) Howes, L.; Asplund, Martin; Casey, A. R.; Keller, S. C.; Yong, D.; Gilmore, G.; Lind, K.; Worley, C.; Bessell, M. S.; Casagrande, Luca; Marino, A. F.; Nataf, D. M.; Owen, C. I.; Da Costa, Gary; Schmidt, Brian; Tisserand, Patrick; Randich, S.; Feltzing, S.; Vallenari, A.; Prieto, C. Allende; Bensby, T.; Flaccomio, E.; Korn, A. J.; Pancino, E.; Recio-Blanco, A.; Smiljanic, R.; Bergemann, M.; Costado, M. T.; Damiani, F.; Heiter, U.; Hill, V.; Hourihane, A.; Jofré, P.; Lardo, C.; de Laverny, P.; Magrini, L.; Maiorca, E.; Masseron, T.; Morbidelli, L.; Sacco, G. G.; Minniti, D.; Zoccali, M.We present the first results of the EMBLA survey (Extremely Metal-poor BuLge stars with AAOmega), aimed at finding metal-poor stars in the Milky Way bulge, where the oldest stars should now preferentially reside. EMBLA utilizes SkyMapper photometry to pre-select metal-poor candidates, which are subsequently confirmed using AAOmega spectroscopy. We describe the discovery and analysis of four bulge giants with −2.72 ≤ [Fe/H] ≤ −2.48, the lowest metallicity bulge stars studied with high-resolution spectroscopy to date. Using FLAMES/UVES spectra through the Gaia-ESO Survey we have derived abundances of twelve elements. Given the uncertainties, we find a chemical similarity between these bulge stars and halo stars of the same metallicity, although the abundance scatter may be larger, with some of the stars showing unusual [α/Fe] ratios.