The optical spectrum of the star SMSS J03130036−6708393 shows no evidence of iron; this, together with comparisons of the star’s observed element abundance pattern with those of models, means that SMSS J03130036−6708393 must have been seeded with material from a single supernova with an original mass about 60 times that of the Sun This study describes a remarkable star discovered in the continuing SkyMapper Southern Sky Survey Known as SMSS 0313–6708, the star's optical spectrum indicates no detectable iron, placing it at least a factor of 30 times lower in iron content than the most iron-poor star known previously The authors conclude that the chemistry of the star carries the imprint of the explosion of a single supernova with an original mass about 60 times that of the Sun Comparisons with four previously discovered low-metallicity stars (where a metal is any element heavier than helium) suggest that low-energy supernovae may have been common in the early Universe, and that such supernovae yielded light-element enrichment with insignificant iron These low-ion stars may be providing a glimpse of processes such as cosmic reionization and the chemical evolution of early galaxies The element abundance ratios of four low-mass stars with extremely low metallicities (abundances of elements heavier than helium) indicate that the gas out of which the stars formed was enriched in each case by at most a few—and potentially only one—low-energy supernova1,2,3,4 Such supernovae yield large quantities of light elements such as carbon but very little iron The dominance of low-energy supernovae seems surprising, because it had been expected that the first stars were extremely massive, and that they disintegrated in pair-instability explosions that would rapidly enrich galaxies in iron5 What has remained unclear is the yield of iron from the first supernovae, because hitherto no star has been unambiguously interpreted as encapsulating the yield of a single supernova Here we report the optical spectrum of SMSS J03130036−6708393, which shows no evidence of iron (with an upper limit of 10−71 times solar abundance) Based on a comparison of its abundance pattern with those of models, we conclude that the star was seeded with material from a single supernova with an original mass about 60 times that of the Sun (and that the supernova left behind a black hole) Taken together with the four previously mentioned low-metallicity stars, we conclude that low-energy supernovae were common in the early Universe, and that such supernovae yielded light-element enrichment with insignificant iron Reduced stellar feedback both chemically and mechanically from low-energy supernovae would have enabled first-generation stars to form over an extended period We speculate that such stars may perhaps have had an important role in the epoch of cosmic reionization and the chemical evolution of early galaxies

A single low-energy, iron-poor supernova as the source of metals in the star SMSS J031300.36−670839.3

We present the first data release of the SkyMapper Southern Survey, a hemispheric survey carried out with the SkyMapper Telescope at Siding Spring Observatory in Australia. Here, we present the survey strategy, data processing, catalogue construction, and database schema. The first data release dataset includes over 66 000 images from the Shallow Survey component, covering an area of 17 200 deg2 in all six SkyMapper passbands uvgriz, while the full area covered by any passband exceeds 20 000 deg2. The catalogues contain over 285 million unique astrophysical objects, complete to roughly 18 mag in all bands. We compare our griz point-source photometry with Pan-STARRS1 first data release and note an RMS scatter of 2%. The internal reproducibility of SkyMapper photometry is on the order of 1%. Astrometric precision is better than 0.2 arcsec based on comparison with Gaia first data release. We describe the end-user database, through which data are presented to the world community, and provide some illustrative science queries.

/pdf/skymapper-southern-survey-first-data-release-dr1-p613iqkvn9.pdf

SkyMapper Southern Survey: First Data Release (DR1)

Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an optical fiber-bundle integral-field unit (IFU) spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). With a spectral coverage of 3622–10354 A and an average footprint of ~500 arcsec2 per IFU the scientific data products derived from MaNGA will permit exploration of the internal structure of a statistically large sample of 10,000 low-redshift galaxies in unprecedented detail. Comprising 174 individually pluggable science and calibration IFUs with a near-constant data stream, MaNGA is expected to obtain ~100 million raw-frame spectra and ~10 million reduced galaxy spectra over the six-year lifetime of the survey. In this contribution, we describe the MaNGA Data Reduction Pipeline algorithms and centralized metadata framework that produce sky-subtracted spectrophotometrically calibrated spectra and rectified three-dimensional data cubes that combine individual dithered observations. For the 1390 galaxy data cubes released in Summer 2016 as part of SDSS-IV Data Release 13, we demonstrate that the MaNGA data have nearly Poisson-limited sky subtraction shortward of ~8500 A and reach a typical 10σ limiting continuum surface brightness μ = 23.5 AB arcsec-2 in a five-arcsecond-diameter aperture in the g-band. The wavelength calibration of the MaNGA data is accurate to 5 km s-1 rms, with a median spatial resolution of 2.54 arcsec FWHM (1.8 kpc at the median redshift of 0.037) and a median spectral resolution of σ = 72 km s-1.

/pdf/the-data-reduction-pipeline-for-the-sdss-iv-manga-ifu-galaxy-hzvpytjg2c.pdf

The data reduction pipeline for the SDSS-IV MaNGA IFU Galaxy Survey

We present an integral field spectroscopic study of two nearby luminous infrared galaxies (LIRGs), IC 1623 and NGC 3256, which exhibit evidence of widespread shock excitation induced by ongoing merger activity. We show the importance of carefully separating excitation due to shocks versus excitation by H II regions and the usefulness of integral field unit data in interpreting the complex processes in LIRGs. Our analysis focuses primarily on the emission line gas, which is extensive in both systems and is a result of the abundant ongoing star formation as well as widespread LINER-like excitation from shocks. We use emission line ratio maps, line kinematics, line-ratio diagnostics, and new models as methods for distinguishing and analyzing shocked gas in these systems. We discuss how our results inform the merger sequence associated with local U/LIRGs and the impact that widespread shock excitation has on the interpretation of emission line spectra and derived quantities of both local and high-redshift galaxies.

/pdf/galaxy-wide-shocks-in-late-merger-stage-luminous-infrared-1lxn5m22o0.pdf

Galaxy-wide shocks in late-merger stage luminous infrared galaxies

Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an optical fiber-bundle integral-field unit (IFU) spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). With a spectral coverage of 3622 - 10,354 Angstroms and an average footprint of ~ 500 arcsec^2 per IFU the scientific data products derived from MaNGA will permit exploration of the internal structure of a statistically large sample of 10,000 low redshift galaxies in unprecedented detail. Comprising 174 individually pluggable science and calibration IFUs with a near-constant data stream, MaNGA is expected to obtain ~ 100 million raw-frame spectra and ~ 10 million reduced galaxy spectra over the six-year lifetime of the survey. In this contribution, we describe the MaNGA Data Reduction Pipeline (DRP) algorithms and centralized metadata framework that produces sky-subtracted, spectrophotometrically calibrated spectra and rectified 3-D data cubes that combine individual dithered observations. For the 1390 galaxy data cubes released in Summer 2016 as part of SDSS-IV Data Release 13 (DR13), we demonstrate that the MaNGA data have nearly Poisson-limited sky subtraction shortward of ~ 8500 Angstroms and reach a typical 10-sigma limiting continuum surface brightness mu = 23.5 AB/arcsec^2 in a five arcsec diameter aperture in the g band. The wavelength calibration of the MaNGA data is accurate to 5 km/s rms, with a median spatial resolution of 2.54 arcsec FWHM (1.8 kpc at the median redshift of 0.037) and a median spectral resolution of sigma = 72 km/s.

/pdf/the-data-reduction-pipeline-for-the-sdss-iv-manga-ifu-galaxy-35pda87eee.pdf

The Data Reduction Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey

This paper describes the on-telescope performance of the Wide Field Spectrograph (WiFeS). The design characteristics of this instrument, at the Research School of Astronomy and Astrophysics (RSAA) of the Australian National University (ANU) and mounted on the ANU 2.3 m telescope at the Siding Spring Observatory has been already described in an earlier paper (Dopita et al. in Astrophys. Space Sci. 310:255, 2007). Here we describe the throughput, resolution and stability of the instrument, and describe some minor issues which have been encountered. We also give a description of the data reduction pipeline, and show some preliminary results.

The Wide Field Spectrograph (WiFeS): performance and data reduction

This paper describes the on-telescope performance of the Wide Field Spectrograph (WiFeS). The design characteristics of this instrument, at the Research School of Astronomy and Astrophysics (RSAA) of the Australian National University (ANU) and mounted on the ANU 2.3m telescope at the Siding Spring Observatory has been already described in an earlier paper (Dopita et al. 2007). Here we describe the throughput, resolution and stability of the instrument, and describe some minor issues which have been encountered. We also give a description of the data reduction pipeline, and show some preliminary results.

The Wide Field Spectrograph (WiFeS): Performance and Data Reduction

TAROS is a system that will allow The Australian National University telescopes at Siding Spring Observatory to be operated automatically or interactively with authenticated control via the Internet. In the context of remote interactive observing, TAROS is operated by a Java GUI front-end which incorporates JSky components and relies on two key Java technologies: Java Message Service and Java Native Interface. This paper, the third in the TAROS series, describes the TAROS client application for remote interactive observing and its underlying GUI framework.

Anthony Green

Papers

The Wide Field Spectrograph (WiFeS): performance and data reduction

The Wide Field Spectrograph (WiFeS): Performance and Data Reduction

A Java GUI Client for Remote Interactive Observing: a Front-End to the Telescope Automation and Remote Observing System (TAROS)