Australia Telescope National Facility

The Australia Telescope National Facility presents the 2009 AstroFest, a full day symposium showcasing research carried out using the National Facility. It provides an opportunity for students, post-docs and astronomers from all walks of life to share their discoveries and experiences with the rest of the community. Talks will be 10-15 minutes in length with 5 minutes for questions/answers. Lunch and coffee/tea breaks will be provided for all Astrofest participants.

The AstroFest will be held on the 10th of December 2009, at the ATNF headquarters in Marsfield. Additionally, it will be immediately followed by the 3rd ATNF Gravitational Wave Workshop on the 11th of December 2009. The Gravitational Wave workshop is open to all and will contain talks/discussion on millisecond pulsar timing and gravitational wave astrophysics. So please make these days available in your diary/calendar.

Programme of Speakers

Thursday 10th December (AstroFest)

09:00
Tobias Westmeier
(ATNF)
"Gas and Dark Matter in Galaxy Groups"The new generation of radio telescopes and instruments (ASKAP, MeerKAT, WSRT/Apertif) will provide an unprecedented combination of large field of view and high sensitivity ideally suited to study nearby galaxy groups. Deep, wide-field HI observations of galaxy groups are an excellent tool to study the structure and evolution of galaxies and shed light on interaction and feedback processes in the group environment.

In my presentation I will discuss the feasibility of deep HI studies of nearby galaxy groups with different telescopes. To illustrate the prospects of galaxy group studies, I will present the latest results of deep HI observations towards the Sculptor Group with the ATCA and explain what we can learn from such observations about the structure and evolution of galaxies. I will also show how we can use the effects of ram pressure interaction on the outer discs of galaxies to constrain the physical parameters of the intergalactic medium in galaxy groups.
09:20
Bjorn Emonts
(ATNF)
"CO in high-z radio galaxies with CABB"We present result of a pilot-project on observing molecular CO(1-0) gas in high-redshift radio galaxies with the Compact Array Broadband Backend (CABB). We obtained spectral-line observations of two powerful radio galaxies at z=2.5-3, using the 1 MHz 'continuum' channels of CABB across the full 2 GHz band (resulting in a velocity resolution of 10 km/s at the high observing frequencies of the redshifted CO line). Results of our study show that CABB is very well suited for high-redshift CO work and that the large bandwidth is an enormous advantage over the often narrow velocity ranges that have been feasible so far. One of the two systems observed (MRC 0943-242) shows a tentative off-nuclear detection of CO(1-0), indicating that perhaps as much as several x 10^10 Msun of molecular hydrogen gas is present in this system.
09:40
Angel Lopez-Sanchez
(ATNF)
"TBA"TBA
09:55
Keith Bannister
(USyd)
"Fast transients and interferometers"Searching for dispersed radio emission from pulsars, rotating radio transients and other fast transients is computationally challenging for single dishes, and can be overwhelming for interferometers. Traditional approaches with interferometers have sacrificed either sensitivity or field of view to reduce the size of the burden. I will discuss a new, computationally tractable approach for detecting dispersed emission with interferometers which simultaneously maintains the full sensitivity and field of view. It is called: The Chirpolator.
10:15
Naomi McClure-Griffiths
(ATNF)
"A Magnetised High Velocity Cloud?"It is thought that that magnetic fields are necessary in High Velocity Clouds (HVCs) to stabilise the clouds against instabilities that develop as the clouds travel through the Milky Way halo. Yet, despite searches dating back for nearly 20 years, magnetic fields have never been conclusively detected in any HVCs surrounding the Milky Way. Searching for finding magnetic fields in HVCs is fairly hard work, focussing mainly on attempts to detect HI Zeeman splitting in absorption through the clouds. An alternative technique is to search for Faraday rotation in HVCs. We have compared the recently released NVSS rotation measure catalogue (Taylor et al 2009) to all known HVCs and found a likely correlation with one HVC in the Magellanic Leading Arm. I will present the HVC in question, attempt to set limits on the magnetic field strength and discuss its implications for HVC stability.
10:30
Tea & Coffee
11:00
Jimi Green
(ATNF)
"Methanol Multibeam Survey"A brief update on the progress of the Methanol Multibeam Survey, a Parkes based survey to observe 6.7-GHz methanol masers in our Galaxy.
11:10
Max Voronkov
(ATNF)
"Class I methanol masers and evolutionary stage of star formation"The question whether different masers trace distinct evolutionary stages of high-mass star formation has been investigated for more than two decades. The analysis of the recent survey for 9.9-GHz methanol masers (collisionally pumped masers or class I) allows us to suggest that class I masers may be associated with expanding HII regions in some sources. This is an alternative scenario to the outflow scenario which is often assumed. We also revise as to where these masers fit into evolutionary sequence. There are indications that class I masers may outlast class II (radiatively pumped, 6.7-GHz masers are a good example) methanol masers and have a significant overlap in time with OH masers.
11:30
Greg Madsen
(USyd)
"Magnetic Fields in Nearby HII Regions"Magnetic fields pervade interstellar space and are involved in a number of important astrophysical processes. Significant progress has been made recently in quantifying interstellar magnetism in a range of environments. However, many detection techniques depend on various assumptions in order to infer properties of the field. We report on new Faraday rotation measurements toward several nearby HII regions that enable us to measure their line-of-sight magnetic field with minimal uncertainties. We quantify the average field and its variation within the HII regions, and discuss the implications of our results on the nature of HII regions and the large-scale Galactic field. We highlight the role that ASKAP will play in transforming our understanding of magnetic fields in the universe.
11:50
Maik Wolleben
(DRAO)
"The Parkes 300-900 MHz Rotation Measure Survey"The Parkes 300-900 MHz Rotation Measure Survey is a wide-band, spectro-polarimetric survey of the diffuse polarized emission of the southern sky. Observations began in September 2009. Our prime objective is to study the magneto-ionic medium of our local Galaxy: its magnetic field and the ionized gas. The frequency coverage gives excellent sensitivity to Faraday rotation structures and Rotation Measure Synthesis will allow us to resolve those structures in 3D. The Parkes survey forms part of a larger project: the Global Magneto-Ionic Medium Survey (GMIMS), whose aim is to map the entire sky from 300 MHz to 1.8 GHz.

We use a new wide-band receiver, specifically designed and built for this survey at DRAO in Penticton. The receiver is based on the so-called Eleven-feed by P. S. Kildal. Ionospheric Faraday rotation and radio frequency interference present the biggest challenges for this survey.

In this talk I will briefly discuss the scientific objectives for this survey, our experiences in designing and using an Eleven-feed antenna, the GMIMS project, and (hopefully) show some preliminary data from the northern and southern skies.
12:10
Emil Lenc
(ATNF)
"High Dynamic Range Imaging with the CABBerrific ATCA"The Compact Array Broadband Backend (CABB) offers tremendous potential for users of the ATCA. However, to get the most out of CABB requires careful attention. I will look at some of the "tricks of the trade" when it comes to getting the most out of CABB data and ATCA data in general.
12:30
Lunch
13:30
Christopher Mathew Wright
(UNSW@ADFA)
"Resolving structure in the HD100546 disk at millimetre and centimetre wavelengths"Several lines of evidence demonstrate the existence of a circumstellar disk around the Herbig Be star HD100546. Structure within the disk, such as an inner cavity and spiral pattern, as well as almost identical mineralogy of the dust grains to those seen in our own solar system, further suggest that the growth to planets may be well underway.

To learn more about the processes occurring in this disk we have conducted a multi-frequency observing program with the Australia Telescope Compact Array (ATCA). At 3, 7 and 16 mm we have resolved the emission region, which probably consists of a compact disk of FWHM ~ 50 AU and an envelope of FWHM >= 100 AU. The spectral index of the dust emission (integrated over the whole region) is ~ 2.3+/-0.2, and thus the dust opacity index is ~ 0.3. When compared to dust models in the literature this suggests a maximum size of a few tens of centimetre.

There is structure to the mm dust emission on a spatial scale broadly resembling the spiral pattern seen in scattered light images. At 3 and 7 mm we also resolve an inner disk clearing on the scale of a few tens of AU, also known from published scattered light and mid-IR images.

We also present HCO+ J=1-0 line data which demonstrates the presence of dense molecular gas in the disk. The line profile is double-peaked, with component velocities at ~ 3.5 and 7.0 km/s. Channel maps indicate a slight spatial offset between these velocity components, approximately along the disk major axis. If interpreted as Keplerian rotation the radius of the emission is ~ 350 AU, with the south-east side approaching and the north-west side receding from Earth.

Overall our results suggest that HD100546 is probably younger than hitherto thought, perhaps less than 5 Myr instead of >= 10 Myr as generally assumed.
13:50
Sarah Maddison
(Swinburne)
"CABB observations of the debris disk beta Pic"Debris disks represent the final evolutionary phase of protoplanetary disks around young stars. While large planetesimals are undetected, visible and near infrared emission from short-lived grains produced by collisions between these asteroid-sized bodies can reveal the distribution of the planetesimal population. Understanding the spatial and size distribution of the grains sheds light on the physical conditions and dynamics of debris disk, which is the basic information needed to understand the physics of disks when planets are forming.

At least two grain populations are believed to exist in the nearby southern debris disk beta Pictoris disk: large dark particles that dominate the thermal emission, and much smaller grains responsible for the optical near infrared scattered light observations. With the recent announcement of a planet around beta Pic, it is now all the more important to try to obtain mm maps to compare with the 850micron and 1.2 mm maps to and how the planet “stirs up” the dust. Here we present the first 3+7mm images of beta Pic with the new CABB system.
14:10
Dick Manchester
(ATNF)
"The Parkes Pulsar Timing Array Project"Millisecond pulsars have extremely stable periods and small perturbations in the observed periods due to gravitational waves (GW); passing over the Earth and the pulsar can in principle be detected using a so-called “Pulsar Timing Array”. The Parkes Pulsar Timing Array (PPTA) project has been timing 20 millisecond pulsars for about four years with steadily improving observing and analysis systems. Similar PTA systems are under development in North America (NANOGrav); and Europe (EPTA). We are now approaching our design goals and should be able to detect the predicted levels of the stochastic GW background from binary super-massive black holes in the cores of distant galaxies in 5 – 10 years. We have also used the pulsar timing data to measure an extremely precise mass for Jupiter and other applications are planned.
14:30
Sarah Burke-Spolaor
(Swinburne)
"Mysterious Radio Impulses at Parkes Telescope"Single-pulse searches of archival pulsar data have yielded the detection of 16 swept-frequency signals that appear of strikingly similar form to the "extragalactic Lorimer burst" discovered two years ago, however the new detections have many properties implying a terrestrial origin. In this talk the strange features of these bursts, possibilities of their origin, and implications for future extragalactic pulse searches are discussed.
14:50
Fredrick Jenet
(UTB)
"The discovery of faster-than-light pulse propagation in interstellar space: a new tool to study the interstellar medium"The discovery of faster-than-light pulse propagation in interstellar space: a new tool to study the interstellar medium.
15:00
Tea & Coffee
15:30
Lina Levin
(Swinburne)
"The First Magnetar Discovered in Radio"An extremely bright pulsar, PSR J1623-4949B, was found during observations for the High Time Resolution Universe survey at Parkes, with the highest surface magnetic field strength of any radio pulsar known (~2.7*10^14 G). The pulsar shows great variability in flux and in pulse profile, a behaviour not seen in ordinary pulsars but that is typical for the group of neutron stars called Magnetars. Even though many attempts to find radio emission from the existing magnetars have been made, only two of the 15 confirmed magnetars (both Anomalous X-ray Pulsars) have been observed to emit also in radio, and in both cases the radio pulsations have been correlated with a strong X-ray outburst. Data from the X-ray monitors show no significant X-ray outburst close to the position of J1623-4949B during the recent years, suggesting that it could be the first Radio Magnetar and would then provide an important link between magnetars and ordinary pulsars.
15:50
Matthew Bailes
(Swinburne)
"Newly-discovered Millisecond Pulsars from the High Time Resolution Universe Survey"The new digital pulsar survey at Parkes is unveiling new millisecond pulsars previously smeared out by the course analogue filterbanks.

I will describe how these pulsars are changing our ideas about the luminosity function and spin period distributions, and one exciting object that is exhibiting strong eclipses.
16:10
Emily Petroff
(Carleton College)
"Modelling the Interstellar Scattering of Polarized Pulsar Signals"Pulsars have measurable variations in position angle of linear polarization across the pulse. Predictions about the variation of polarization position angle (PA) can be made using the rotating vector model but observed position angle swings are not always in accordance with this model. In an attempt to explain this discrepancy I simulated polarized pulsar profiles and separately convolved each Stokes parameter with exponential scattering functions to determine whether interstellar scattering could provide an explanation. Scattering by moderate to high timescales (τ= 4-8 ms) in the presence of orthogonal position angle jumps resulted in distorted PA swings similar to those observed from real pulsars.

These results validate previous hypotheses about the connection between apparent non-orthogonal PA jumps and interstellar scattering. They can also potentially be used in an attempt to explain further discrepancies between observation and theory, such as apparent RM variation across the pulse.
16:30
Gregory Tsarevsky
(Astro Space Centre, Moscow)
"Wonders of the Cluster of Galaxies A3827: A deep search for Gravlensing in Radio and Optics"A3827 is a rich, compact, X-ray luminous cluster of galaxies with a high velocity dispersion of ~1000 km/s, i.e. containing a high mass in the centre potentially causing a gravitational lensing. Our high sensitivity observations obtained in the radio with ATCA (~15 uJy rms in C- and X-bands) and optical with GEMINI_South (lim. mag. ~28 R), have revealed a gallery of unique and puzzling objects including our first-ranked target - a possible strong lens-like feature in the radio. There also is an evidence that the peculiar central cD complex consists of a massive binary.
16:40
Simon Johnston
(ATNF)
"Gamma-ray pulsars and the Fermi/Parkes collaboration"The Fermi gamma-ray satellite was launched in June 2008 and has returned some amazing results on gamma-ray pulsars. I will give a brief outline of the new results and the role Parkes has been playing to connect radio and gamma-ray data.

Friday 11th December (3rd ATNF Gravitational Wave Workshop)

09:00
George Hobbs
(ATNF)
"Status report on the PPTA/IPTA projects"
09:20
Willem van Straten
(Swinburne)
"Polarisation calibration and timing"
09:40
Matthew Bailes
(Swinburne)
"New instrumentation for pulsar timing"
10:00
Stefan Oslowski
(Swinburne)
"An analysis of single pulses from PSR J0437-4715"
10:20
Tea & Coffee
10:40
Sarah Burke-Spolaor
(Swinburne)
"Observational limits on binary black holes in galaxies"
11:00
Fredrick Jenet
(UTB)
"Constraining the coalescence rate of supermassive black-hole binaries using pulsar timing"
11:20
Daniel Yardley
(USyd)
"Results from trying to detect a GW background in pulsar timing data"
11:40
Richard Schilizzi
(SKA)
"The SKA project and pulsar timing arrays"
12:00
Ron Ekers
(ATNF)
"Finding supermassive binary black holes"
12:20
Lunch
13:20
Xavier Siemens
(UWM)
"Gravitational wave stochastic background from cosmic (super)-strings"
13:40
Dick Manchester
(ATNF)
"Determining the Jovian system mass"
14:00
Emily Petroff
(Carleton College)
"Initial results from an analysis of frequency derivative switching in PSR B1937+21"
14:20
Larry Price
(UWM)
"A new technique to limit the GW background "
14:40
Jonathan Khoo
(ATNF)
"An update on the PULSE@Parkes project"
15:00
Tea & Coffee
15:20
Willem van Straten
(Swinburne)
"The APSR system"
15:40
Ettore Carretti
(ATNF)
"Update on the Parkes backend rationalisation project"
15:50
Arkadi Kosymnin
(ATNF)
"The Parkes data archiving project"
16:00
Graeme Carrad
(ATNF)
"Update on the Parkes receiver rationalisation project "
16:10
Simon Johnston
(ATNF)
"Future telescopes and their role for pulsar research"
16:30
Dick Manchester
(ATNF)
"Discussion on next steps for PPTA/collaborations"

Video/Telephone Conferencing details

AstroFest Morning Session

AstroFest Afternoon Session

Gravitational Wave Workshop Morning Session

Gravitational Wave Workshop Afternoon Session

Registration

Registration for presenting at the AstroFest is closed, however, attendees are still welcome to join in.

Travel and Accommodation

The AstroFest will be held in the lecture theatre at the CSIRO site in Marsfield, NSW. Details of how to get to the site via public transport are available from the ATNF visitors page. Although we cannot arrange accommodation for attendees, a list of local hotels and contact numbers is available.