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# ACAMAR 5: Australia-China Workshop on Astrophysics – Program

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## Tue, 2 Apr

### Session 1: Country Updates

RACV Healesville Country Club — Chair: Professor Elaine SADLER, CSIRO Astronomy and Space Science

### 9:10 –9:35 a.m. — Australia Professor Rachel WEBSTER, University of Melbourne/AAL

Prof. Webster will give an overview of Australian astronomy

### 9:35 –10:00 a.m. — China Professor Ji YANG, Purple Mountain Observatory, CAS

Prof. Xue will give an overview of Chinese astronomy

### Session 2: Radio Astronomy

RACV Healesville Country Club — Chair: Professor Elaine SADLER, CSIRO Astronomy and Space Science

TBD

### 10:50 –11:05 a.m. — Radio Astronomy Technologies at CSIRO Dr Tasso TZIOUMIS, CSIRO

CSIRO Astronomy and Space Science (CASS) runs a strong Technologies Program engaged in developing new systems for radio astronomy utilising the latest technological advances. In particular, CASS has developed new Phased Array Feed (PAF) systems already in commissioning for ASKAP and is developing a new cryoPAF system for Parkes with unparalleled sensitivity, using the new "rocket" PAF feeds. The other major advance is in Ultra Wide Band (UWB) systems covering a 6:1 frequency range and achieving a constant beam over all frequencies using novel techniques. The first of these systems has been recently commissioned at Parkes. For both the PAF and UWB systems CASS has also developed "state-of-the-art" FPGA-based digital systems to process the large amounts of data generated. The next generation of digital signal processing systems is also under development using the revolutionary RF-System-on-a-Chip (RFSoC) recently released by Xilinx. An overview of these developments and the latest advances will be presented.

### 11:05 –11:20 a.m. — Future Prospects for Joint Australia-China Cooperation in the Context of the Murchison Widefield Array Professor Melanie JOHNSTON-HOLLITT, Curtin University

I will present an overview of the activities associated with the Murchison Widefield Array (MWA) with a particular focus on the upgraded instrument, future plans, and joint Australian-Chinese research efforts.

### 11:20 –11:40 a.m. — FAST Science update/Review of FAST HI Survey Plan Dr Ming ZHU, National Astronomical Observatory of China

Large scale HI survey is one of the major science drive for the Five Hundred meter Aperture Spherical radio Telescope (FAST). Here we review the FAST extra-galactic HI survey plan based on the preliminary results of test observations during FAST commissioning period. The under-planning FAST survey will focus on observations deeper than that of ALFALFA survey in order to answer important questions on galaxy formation and evolution. We also propose to make deep mapping of the diffuse HI gas around nearby galaxies and study the integrated HI emission on group and cluster scales. Synergies between the FAST HI survey and other ongoing HI surveys using the SKA pathfinder instruments will also be discussed .

### 11:40 –11:55 a.m. — Updated results from the Parkes/FAST collaboration Dr Andrew David CAMERON, Commonwealth Scientific and Industrial Research Organisation (Astronomy and Space Science)

Since its first light in 2016, the Five-hundred-metre Aperture Spherical Telescope (FAST) in southern China has already been producing a steady stream of new astronomical discoveries particular with regard to radio pulsars. Over 60 new pulsars have already been identified through early observations, and the imminent Commensal Radio Astronomy FAST Survey (CRAFTS) promises to produce orders of magnitudes more. The Parkes/FAST collaboration is an ongoing scientific partnership between the CSIRO and NAOC, intended to support FAST during this early science work. Over the past 1.5 years, the Parkes radio telescope has observed, confirmed and studied many of these new pulsar discoveries, and has also supported a number of additional science projects led by Chinese PIs. Here we will present some of the most exciting and recent results from this work, as well as a look to the future of this productive collaboration.

### 11:55 a.m. –12:10 p.m. — Early Science results from the Parkes ultra-wide bandwidth receiver Dr George HOBBS, CSIRO

An ultra-wide bandwidth receiver system (UWL) has recently been installed on the Parkes 64m-diameter radio telescope. I will describe the properties of this receiver system, show example scientific results (relating to high time resolution and high frequency resolution observations), describe our future plans for the system and discuss the role of wide-band receivers on single dish telescopes in Australia and China (including both FAST and QTT).

### 12:10 –12:25 p.m. — How to detect ultra-high-energy cosmic rays with FAST Dr Clancy William JAMES, ICRAR/Curtin

The Five hundred meter Aperture Spherical Telescope, FAST, offers the first opportunity to detect ultra-high-energy cosmic rays impacting the Moon. When these rare particles interact, they produce a burst of radio waves lasting a few nanoseconds. Pointing a radio telescope at the Moon, and searching for ultra-short pulses, allows the 20 million km2 visible lunar surface to be turned into a giant cosmic ray detector. The ultimate goal is to detect enough of these particles to uncover their origin. Until now however, no experiment has had the sensitivity to detect the signature of a single particle from over a light-second's distance. This talk describes how to use FAST to search for ultra-high-energy cosmic rays. The necessary experimental steps are laid out, which have been developed by the LUNASKA project on the Parkes radio telescope. Current theoretical uncertainties due to lunar surface effects are also described, as is a method to resolve these. Finally, event rate estimates with both current and future FAST receives are given, which points the way to an experiment to resolve the origin of the highest energy particles in nature.

### 12:25 –12:40 p.m. — FAST-MWA Synergies in Pulsar and Fast Radio Burst Science Dr Ramesh BHAT, ICRAR, Curtin University

The geographic locations, operating frequencies and contemporaneous sky visibility bring exciting scientific synergies between the Murchison Widefield Array (MWA) and the Five-hundred metre Aperture Spherical Telescope (FAST) in the areas of pulsars and fast radio bursts (FRBs). While the unprecedented collecting area of FAST makes it a superbly sensitive instrument to search for pulsars, the MWA’s prodigious field of view makes it a powerful survey instrument at low radio frequencies. The MWA pulsar team is building high time resolution digital archives of the entire southern sky by leveraging the MWA’s voltage capture functionality and the newly commenced all-sky pulsar survey (SMART), the data from which can be readily mined for low-frequency detections of new pulsars, and follow-up studies of promising candidates, that will emerge from the Commensal Radio Astronomy FAST Survey (CRAFTS). The low frequencies and electronic steering capabilities also make the MWA a powerful instrument for rapid follow-ups of FRBs that will be detected by the CRAFTS project.

### Session 3: Student Talks

RACV Healesville Country Club — Chair: Professor Bo QIN, NAOC

### 1:30 –1:40 p.m. — Gas Temperature Demography in the Magellanic Clouds Mr Boyang LIU, UWA/ICRAR

A galaxy's star formation rate is partially determined by how quickly gas converts from di!use atomic (HI) state to molecular (H2). This HI-H2 conversion is a!ected by the amount of metal in the gas and the strength of interstellar radiation fields. We have conducted an Australia Telescope Compact Array (ATCA) observation project that uses HI absorption to probe the HI-H2 conversion within disparate environments in two local laboratories: the nearby Large and Small Magellanic Clouds. This project will complement the ASKAP survey, GASKAP and help us understand the gas processes that lead to star formation and how these impact galaxy evolution throughout the Universe. Our project observed 48 sightlines in LMC and 31 in SMC with 6km configuration of ATCA telescope, which doubled the total number of sampling. We will present the results for the temperature distribution of atomic gas in the Magellanic Clouds and its implications for our knowledge of ISM evolution and galaxy formation.

### 1:40 –1:50 p.m. — Southern Pulsar Census and Polarimetric Studies with the MWA Ms. Mengyao XUE, ICRAR-Curtin

The Murchison Widefield Array (MWA) provides an excellent opportunity to extend the frequency range of pulsar observations in the Southern Hemisphere. In 2017 we carried out an initial census of a large sample of known (i.e., catalogued) pulsars at 185 MHz using the MWA Voltage Capture System (VCS), which records raw (unprocessed) data from a maximum of 128 MWA tiles at high-time and high-frequency resolutions (100 us, 10 KHz). This led to the successful detection of 65 pulsars (including six millisecond pulsars and two in binary system), but using only ~10% of the full-array sensitivity, as the detected powers from the tiles were incoherently summed. We are currently reprocessing these data using the new tied-array (i.e. phased array) beam-former pipeline for high-time resolution, full-polarimetric studies of a large sample of pulsars. The analysis is currently underway and also necessitated a detailed characterisation of the polarimetric performance of the MWA in tied-array mode, using two bright southern pulsars, PSR J0742-2822 (moderately polarised) and PSR J1752-2806 (highly polarised). Our analysis suggests that reliable pulsar polarimetry can be realised at frequencies < 270 MHz at zenith angles < 45 degrees. Our analysis also led to first low-frequency polarimetric studies of these two pulsars, high-precision determinations of their Faraday rotation measurements, and an intriguing result, where the degree of linear polarisation of one of the pulsars showing a steady (and rapid) decline at the low frequencies of the MWA. I will present these developments, our initial interpretation and current efforts toward further detailed follow-ups using the low-frequency capabilities of the MWA and other facilities.

### 1:50 –2:00 p.m. — HI intensity mapping with Parkes telescope Mr. Lincheng LI, National Astronomical Observatories,Chinese Academy of Sciences

to be submitted later...

### 2:00 –2:10 p.m. — The HI mass function in Arecibo Ultra-Deep Survey Mr Hongwei XI, National Astronomical Observatories, Chinese Academy of Sciences

Arecibo Ultra Deep Survey (AUDS) is a blind HI survey targeting galaxies beyond local universe using the 21 cm emission line. The Arecibo $L$-band Feed Array is employed, which gives a upper limit of redshift 0.16. The survey covers two regions located in opposite directions, minimising cosmic variance and ensuring that all observations were able to be performed at night when RFI is weakest. The total area covered was about 1.35 deg$^2$, and total on-source integration time is over 700 hours. The long integration time and small observation area makes it the most sensitive HI survey yet undertaken, with the rms reaching as low as 60 $\mu$Jy per velocity channel. We have so far detected around 250 galaxies. The mass range is log($M_{HI}$/$M_\odot$)-2log$h$ = 5.85-10.29. The furthest galaxy is located at 560 Mpc. Both 1/V$_{max}$ and 2DSWML methods are used to derive the HI mass function (HIMF). The former method results in a faint-end slope $\alpha = -1.36\pm 0.07$, characteristic mass $\log(M_* h^2/M_\odot) = 9.62\pm 0.10$, and density $\Phi_* = (5.18\pm 1.44)\times 10^{-3} h^3$ Mpc$^{-3}$ dex$^{-1}$, while the latter gives $\alpha = -1.17\pm 0.10$, $\log(M_* h^2/M_\odot) = 9.43\pm 0.10$, and $\Phi_* = (7.04\pm 2.14)\times 10^{-3} h^3$ Mpc$^{-3}$ dex$^{-1}$. The sample is divided into high- and low-redshift subsamples to investigate the evolution of HIMF. A slight evolution of the HIMF is present in both methods with $\alpha$ decreasing and $M_*$ increasing with redshift. Similar observations will be possible with FAST, but with much greater sensitivity, larger field of view, better RFI environment, and a higher redshift limit of 0.35, twice as high as available with ALFA.

### 2:10 –2:20 p.m. — Early Results with FAST Relating to Pulsars Ms Lei ZHANG, National Astronomical Observatories of China

PSR J1926−0652, a pulsar recently discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Using sensitive single-pulse detections from FAST and long-term timing observations from the Parkes 64-m radio telescope, we probe phenomena on both long and short time scales. The pulsar exhibits multiple profile components, short-term nulling and subpulse drifting and intermittency on scales of tens of minutes. There is currently no single physical model that can explain all of these phenomena. We therefore proposed a simultaneous observation with China (FAST) and Australia telescopes (Parkes and ATCA) to obtain a deeper understanding of this unusual pulsar and drifting and nulling in general.

### 2:20 –2:30 p.m. — Single pulse search with Parkes data archive Mr Songbo ZHANG, Purple Mountain Observatory, Chinese Academy of Science

We will report the discovery of a new fast radio burst (FRB), FRB 010312, in archival data on Data Access Portal (DAP). This burst is one of the broadest found to date, the second earliest FRB known, and the ninth FRB discovered with a dispersion measure larger than 1000 cm^{-3} pc. As this is only the start of our search, we will also introduce our further search of the whole DAP which contains more than 30 years archival data of Parkes telescope and the idea of a big single pulses database.

### Session 4: Radio Astronomy (Cont)

RACV Healesville Country Club — Chair: Professor Bo QIN, NAOC

### 2:30 –2:45 p.m. — HI Observations of Planck Catalogue of Galactic Cold Clumps (PGCC) with FAST Dr Ningyu TANG, National Astronomical Observatories, Chinese Academy of Science

The Planck Catalogue of Galactic Cold Clumps (PGCC) are believed to be in the early phases of star formation. To investigate the transition from atomic to molecular gas in these clumps, HI observations toward PGCC sources were taken with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). HI Narrow Self-Absorption (HINSA), which associates with cold HI gas in molecular cloud is introduced. We present primary results here.

### 2:45 –3:00 p.m. — A novel geometric wavelet based radio dynamic range imaging method Associate Professor HAO SHAN, Xinjiang Astronomical Observatory

The future SKA has a series of characteristics, such as large field of view, high dynamic, multi-beam, broadband, high frequency and high time resolution, etc. In our research, we also find that radio images has complex characteristics, which can be represented in multi-scales and multi-directions. In this paper, we try to realize a geometric wavelet based dynamic range imaging while retaining important visual information, such as the multi-scale and multi-direction features.Multi-scale image processing techniques have been used in the filed of high dynamic imaging, however they will cause halo artifacts when used for range compression. In these methods, wavelet based mehtods, especially the symmetrical analysis-synthesis filter bank aided by a local gain control of the subbands can work when properly implemented. It can also adapted for the related problem of “companding”, in which an HDR image is converted to an LDR image, and later expanded back to high dynamic range. However,as is known to all, the tensor product based wavelet has disadvantages in represented point sources, but a fatal flaw in representing the curve-like or extended sources, which can be summed up as the second-order continuously differentiable sigularities. The needle-shaped elements can realize a perfect representations for extended sources. In recent research, we use the already published EVLA images, and we find that geometric wavelet, such as curvelets and shearlets in the dynamic range imaging can avoid halo artifacts while retaining important visual information. The experimental results prove that this curvelet-based high dynamic iamging method has competitive results and wide application prospects. The future work will include the compressed sensing based innovations.

### Session 5: Data and Centres

RACV Healesville Country Club — Chair: Professor Lister STAVELEY-SMITH, University of Western Australia

### 3:30 –3:50 p.m. — Chinese SKA regional centre progress and early science prepartion Dr Quan GUO, Shanghai Astronomical Observatory

In this talk, we will introduce the progress of developing Chinese SKA regional center prototype and the preparation of SKA early science on behalf of SKA team in Shanghai Astronomical Observatory

### 3:50 –4:05 p.m. — SKA Regional Centres - status and developments Professor Peter QUINN, ICRAR

I will review the status and current development of SKA Regional Centres. The work going on in Australia via the AusSRC Project, the joint efforts of Australia and China through the ERIDANUS project and the collective work of internatonal SRC projects will be discussed. The aim of the SRC efforts is to produce a global network of data and processing centres that are well matched to national needs and the needs of the SKA for the creation of advanced data products by KSP teams and the operation of the SKA Science Archive. Australia and China are well placed to lead major SRC developments in the coming 5-10 years based on the experience with SKA pathfinders and precursors (ASKAP, MWA and FAST) and the ERIDANUS effort.

### 4:05 –4:20 p.m. — IVOA and China-VO Dr Chenzhou CUI, NAOC

The International Virtual Observatory Alliance (IVOA) was formed in June 2002 with a mission to facilitate the international coordination and collaboration necessary for the development and deployment of the tools, systems and organizational structures necessary to enable the international utilization of astronomical archives as an integrated and interoperating virtual observatory. Chinese Virtual Observatory (China-VO) is the national VO project in China initiated in 2002 by Chinese astronomical community leading by National Astronomical Observatories, CAS. China-VO became a member of the International Virtual Observatory Alliance (IVOA) in 2002. As the deputy chair of IVOA and PI of the China-VO, in my talk I will give an overview and current status of the organization, and latest progresses from the China-VO.

### 4:20 –4:35 p.m. — Five Years of China-Chile Cooperation in Astronomy Professor Zhong WANG, Chinese Academy of Sciences South America Center for Astronomy

Since late 2013 China has established an outpost for cooperations in astronomy in Chile, known as CASSACA (Chinese Academy of Sciences South America Center for Astronomy). Over the past five years, it has served the interest of astronomy communities of both countries, and is a focusing point for Chinese scientists who wish to have more access to the Southern Sky. I will give an overview of the work accomplished by CASSACA and discuss the outlook for this Center in the next few years.

### 4:35 –4:50 p.m. — A China - Australia Joint Research Centre in radio astronomy and the Square Kilometre Array Professor Steven TINGAY, ICRAR - Curtin University

will describe a Joint Research Centre in radio astronomy and the Square Kilometre Array, led by Curtin University and the Shanghai Astronomical Observatory. The exact content of the abstract and talk depends (not completely) on the outcome of multi-million dollar proposals currently in the final stages of review under the Australia-China Science and Research Fund (ACSRF), in both China and Australia. The proposal outcomes will be known before ACAMAR5, but not before the abstract submission deadline

### 4:50 –5:10 p.m. — Pulsar activities at NTSC's 40-m radio telescope Dr Jintao LUO, National Time Service Center, CAS

NTSC(National Time Service Center, CAS, China) is running a 40-m radio telescope, which is located in a mountain area that provides good radio environment. Pulsar activities, including instrumentation developments and researches on pulsar time scale, will be told as the main part of the talk. VLBI activities and technical details of the telescope will be introduced with a few slides, as well.

### BREAKOUT: ANTARCTIC ASTRONOMY

RACV Healesville Country Club

### BREAKOUT: JOINT CENTRES

RACV Healesville Country Club

### BREAKOUT: RADIO INSTRUMENTATION AND JOINT SURVEYS

RACV Healesville Country Club

## Wed, 3 Apr

### Session 6: Gravitation Waves and Transients

RACV Healesville Country Club — Chair: Professor Lifan WANG, Purple Mountain Observatory, Chinese Academy of Sciences

### 9:00 –9:20 a.m. — A matter machine - the science case for a high-frequency gravitational-wave observatory Dr Paul LASKY, Monash University

On the 17th of August 2017, gravitational waves from the inspiral of two neutron stars were first observed. Subsequent electromagnetic observations across the spectrum meant that this was arguably the most observed transient event in the history of astronomy. But gravitational waves were not detected from either the merger or post-merger phases of the collision, which occur at gravitational-wave frequencies above many hundreds of Hertz, where the LIGO and Virgo detectors begin losing sensitivity. I will discuss the science case for building a dedicated, high-frequency gravitational-wave observatory. Among other things, such an observatory could detect the merger and post-merger phases of a binary neutron star collision, allowing us to probe exotic nuclear physics in the cores of neutron stars in a regime not accessible with terrestrial experiments.

### Reports from formal and informal Break-out sessions

RACV Healesville Country Club — Chair: Professor Michael ASHLEY, University of New South Wales

### Panel Discussion

RACV Healesville Country Club

### CLOSING REMARKS

RACV Healesville Country Club — Chair: Professor Lifan WANG, Purple Mountain Observatory, Chinese Academy of Sciences

### LUNCH

RACV Healesville Country Club