Search

We present an overview of the SkyMapper optical follow-up program for gravitational-wave event triggers from the LIGO/Virgo observatories, which aims at identifying early GW170817-like kilonovae out to $\sim 200$ Mpc distance. We describe our robotic facility for rapid transient follow-up, which can target most of the sky at $\delta, Comment: 13 pages, 6 figures, Accepted for publication in PASA

The SkyMapper Transient survey (SMT) is exploring variability in the southern sky by performing (a) a rolling search to discover and study supernovæ, and (b) a Target of Opportunity programme that uses the robotic SkyMapper Telescope at Siding Spring Observatory. The supernova survey is obtaining a non-targeted sample of Type Ia supernovæ (SNe Ia) at low redshifts, z < 0.1, and studying other interesting transients found with the search strategy. We have a Target of Opportunity programme with an automatic response mechanism to search for optical counterparts to gravitational-wave and fast radio-burst events; it benefits from SkyMapper’s large field of view of 5.7 sq. deg. and a rapid data reduction pipeline.We present first results of the SMT survey. The SMT pipeline can process and obtain potential candidates within 12 hours of observation. It disentangles real transients from processing artefacts using a machine-learning algorithm. To date, SMT has discovered over 60 spectroscopically confirmed supernovæ, several peculiar objects, and over 40 SNe Ia including one (SNIa 2016hhd) which was found within the first few days of explosion. We have also participated in searches for optical counterparts of gravitational waves, fast radio bursts and other transients, and have published observations of the optical counterpart of the gravitational-wave event GW170817. We also participate in coordinated observations with the Deeper Wider Faster programme, and the Kepler K2 cosmology project.

We report the discovery of the ultra-luminous QSO SMSS~J215728.21-360215.1 with magnitude $z=16.9$ and W4$=7.42$ at redshift 4.75. Given absolute magnitudes of $M_{145,\rm AB}=-29.3$, $M_{300,\rm AB}=-30.12$ and $\log L_{\rm bol}/L_{\rm bol,\odot} = 14.84$, it is the QSO with the highest unlensed UV-optical luminosity currently known in the Universe. It was found by combining proper-motion data from Gaia DR2 with photometry from SkyMapper DR1 and the Wide-field Infrared Survey Explorer (WISE). In the Gaia database it is an isolated single source and thus unlikely to be strongly gravitationally lensed. It is also unlikely to be a beamed source as it is not discovered in the radio domain by either NVSS or SUMSS. It is classed as a weak-emission-line QSO and possesses broad absorption line features. A lightcurve from ATLAS spanning the time from October 2015 to December 2017 shows little sign of variability., 6 pages, 4 figures, accepted for publication in PASA

The report that follows gives glimpses into the enormous amount of work in cosmology over the past three years, both in theory and in observations. It is impossible to do justice, within the space allotted, to all the exciting work and some important topics like structure formation could not be covered. Nevertheless, the contributors to different sections have done a conscientious job and I thank them all. Some of them had to step in to fill the gaps at short notice.

This paper presents the design and science goals for the SkyMapper telescope. SkyMapper is a 1.3-m telescope featuring a 5.7-square-degree field-of-view Cassegrain imager commissioned for the Australian National University's Research School of Astronomy and Astrophysics. It is located at Siding Spring Observatory, Coonabarabran, NSW, Australia and will see first light in late 2007.The imager possesses 16 384 × 16 384 0.5-arcsec pixels. The primary scientific goal of the facility is to perform the Southern Sky Survey, a six-colour and multi-epoch (four-hour, one-day, one-week, one-month and one-year sampling) photometric survey of the southerly 2π sr to g ∼23 mag. The survey will provide photometry to better than 3% global accuracy and astrometry to better than 50 milliarcsec. Data will be supplied to the community as part of the Virtual Observatory effort. The survey will take five years to complete.

The Supernova Working Group (SNWG) was re-established at the General Assembly in Sidney on July 21, 2003, sponsored by Commissions 28 (Galaxies) and 47 (Cosmology). Here we report on some of its activities since 2003.

The earliest spectrum available of a well-observed, local type Ia SN, the UV-optical spectrum of SN 1990N obtained 14 days beforeBmaximum, was modelled with a Monte Carlo code in order to determine its epoch and consequently the rise time from explosion toBmax, which is important for fitting template light curves. If a standard density distribution and composition for the SN ejecta are used, and the Cepheid distance modulus to the host galaxy, NGC4639 in the Virgo cluster, μ = 32.0, is adopted, the spectrum is best reproduced for an epocht= 5.5 ± 1 days, implying for the SN a rise time of 19.5 ± 1 days. For a shorter μ,tis smaller, but for a T-F distance μ = 31.4 the solution is not consistent.

We summarise the proceedings of a workshop on ‘Supernova Remnants, Pulsars and the Interstellar Medium’ which was held at the Special Research Centre for Theoretical Astrophysics at the University of Sydney on 18 and 19 March 1999.

The Supernova Working Group was re-established at the IAU XXV General Assembly in Sydney, 21 July 2003, sponsored by Commissions 28 (Galaxies) and 47 (Cosmology). Here we report on some of its activities since 2005.

We measured the spin-orbit misalignment for WASP-79b, a transiting hot Jupiter from the WASP survey. Using the Rossiter-McLaughlin effect during the transit event, we determined the sky-projected obliquity to be λ = −106+10−8○. This result indicates that the planet is in a nearly polar orbit.

The last five years have seen an explosion of activity to monitor the sky at optical wavelengths. The following summarizes an overview of the range of experiments currently being, or soon to be, undertaken in both cataloguing and monitoring the sky, and suggests scientific opportunities for the short- to medium- term in the arena of optical transient astronomy. In so doing, it applies the philosophy described by Warner (page 3) to the gamut of variability studies that are now burgeoning in observational astronomy.

As far as coordination and planning of observational activities are concerned, the main need for WG-SN activities seem to lie in the field of suitable follow-ups to the many on-going and planned search programs (in particular for SNe Ia's; LOTOSS, NGSS, SNfactory, SNLS, ESSENCE, GOODS, PanStarrs, . . .). With the new robotic 2m-class telescopes (e.g., the Las Cumbres Observatory Global Telescope Network and other robotic telescopes) photometric follow-ups do not seem a major problem, but for most of the searches spectroscopic follow-up requires 4m-class telescopes at least which will become rare in the future. Possible ways out were discussed.

Past investigations have shown a connection between the properties of Type Ia supernovae (SNe Ia) and their host galaxies. We refine these studies using ultraviolet through mid-infrared observations of both nearby and distant SN Ia hosts. We present new results showing that the properties of SNe Ia, both intrinsic and with respect to their use as distance indicators, appear to depend on a combination of metallicity, stellar age, and star-formation rate of the host. We suggest that the stellar population age and location of the supernova progenitor all can play a roll in using SNe Ia as precision distance indicators, and advocate that a multiwavelength approach is one way to disentangle the different influences, resulting in an improvement of 8% in distance measurements.

Type Ia supernovae (SNe Ia) are among cosmology's most useful tools for measuring extragalactic distances. Their intrinsic brightness, MV=−19.2 mag, and precision, σ=0.12 mag, make for a unique combination to precisely probe cosmic expansion from the nearby to the high-redshift Universe. I describe the current state of the art for measuring distances to SNe Ia—focusing on the current challenges which ultimately limit their precision—as well as prospects for further refinement. I also highlight cosmological applications where they have been especially valuable, and briefly review some future projects which plan to exploit SNe Ia.

Type Ia supernovae remain one of Astronomy's most precise tools for measuring distances in the Universe. I describe the cosmological application of these stellar explosions, and chronicle how they were used to discover an accelerating Universe in 1998 - an observation which is most simply explained if more than 70% of the Universe is made up of some previously undetected form of ‘Dark Energy’. Over the intervening 13 years, a variety of experiments have been completed, and even more proposed to better constrain the source of the acceleration. I review the range of experiments, describing the current state of our understanding of the observed acceleration, and speculate about future progress in understanding Dark Energy.

Type la Supernovae have taken on a leading role in measuring extra-galactic distances providing key information about the Hubble Constant and providing evidence of an accelerating Universe. Unfortunately these conclusions are based on an empirical relationship between SN brightness and light curve shape rather than any deep physical understanding. A key ingredient to gaining physical understanding lies in understanding what becomes a SN la progenitor. Essentially all models require a binary system to push a white dwarf higher in mass. I will review the current attempts observational and theoretical to pin down the nature of these important astrophysical objects.