All posts by cflynn

UTMOST has made over 25,000 pulsar timing observations

Dec 2, 2022 : UTMOST-NS has made reached a major milestone, having just made its 25,000th pulsar timing measurement.

We have been timing pulsars in a new Southern Hemisphere program which kicked off at the Molonglo Radio Telescope in April 2021.

Many pulsars are observed daily, as they are in isolated regions of the sky. Other pulsars share the busy sky in the Milky Way, and are timed once a week.

We are timing just over 170 pulsars and magnetars and averaging around 70 pulsar measurements per day, so that the typical pulsar gets observed every few days.

Some of the pulsars being timed in the UTMOST-2D program

The UTMOST team (Matthew Bailes, Marcus Lower and Chris Flynn) have been working with Liam Dunn, George Howitt, Pat Meyers, Christine Yi and Andrew Melatos (University of Melbourne) on a program to measure the amplitude and rate of pulsar glitches.

We check for new glitches after every pulsar observation, using an automated glitch detection method developed at the University of Melbourne.

The program has already picked up a glitch in the bright pulsar “Vela”.

We are using the newly fully-refitted North-South arm of the telescope, installed with in-house developed receivers, using 66 sub-telescopes positioned in an array and operating fully electronically.

UTMOST-2D’s pulsar timing program is a collaboration between Swinburne University of Technology, the University of Sydney and the University of Melbourne.

Upgraded UTMOST finds its first Fast Radio Burst

FRB20221128A, seen across the band of frequencies observed by the Molonglo Radio Telescope.

The UTMOST-2D project has found its first Fast Radio Burst using the Molonglo Radio Telescope.

Fast Radio Bursts are very bright, millisecond time-scale flashes of radio energy that take place every few minutes randomly on the sky. Their origin is one of the most exciting mysteries in astrophysics.

UTMOST-2D is a project to revamp half of the Molonglo Radio telescope to detect FRBs. Molonglo consists of two 1-mile long arms in a flat valley near Canberra in Australia, ideal for detecting radio waves from space and pinpointing their origins. The North-South aligned arm has been refitted with all new hardware over the last 3 years, and has been searching 24/7 for FRBs for the last 18 months, as part of the PhD project of Swinburne University of Technology Centre for Astrophysics and Supercomputing student Ayushi Mandlik.

The Fast Radio Burst is named FRB20221128A, after its discovery date. The pulse is shown below as a function of observing frequency and time — it lasted about 5.5 milliseconds as a bright flash from an otherwise quiet sky.

The event has been announced as an Astronomer’s Telegram — link.

The search begins : UTMOST-2D fully operational

UTMOST-2D has been running 24/7 for over a week, searching for FRBs and timing pulsars with the North-South arm of the Molonglo Radio Telescope. This is the culmination of over 3 years of design, construction, installation and commissioning by engineers and researchers at Swinburne University of Technology’s Centre for Astrophysics and Supercomputing and the Sydney Institute for Astronomy at the University of Sydney.

Full operations were made possible by Swinburne PhD student Ayushi Mandlik‘s work on machine-learning to recognise radio bursts in real time. Her work involved adding tens of thousands of mock FRBs as point sources on the sky at different locations within the Field-of-View while the telescope is live, saving these data, and using them to train a CNN (convolutional neural network) to recognise such events from random noise and terrestrial radio interference. She used the Swinburne University of Technology’s OzStar supercomputer to train UTMOST.

The pulse detector has already picked up thousands of single pulses from known pulsars in its first week of operations, a critical test of its functionality. It has also picked up pulses from an RRAT — a slow pulsar which emits pulses only very occasionally — this is an excellent test of its capacity to find FRBs.

The live FRB-detector makes use of spatial information by searching around the burst to check it has the characteristics of a distant point source, rather than a nearby interference signal such as caused by mobile phones or electrical machinery. This allows it to reject millions of “false positives” and sift down to the very best candidates each day.

A single pulse detected from the pulsar J1752-2806, showing its brightness at 5 positions (directly on target, and two positions northward and two southward) n the sky. The x-axis of the plots is time in units of seconds, and the y-axis is the frequency in MHz. The brightness of the source fades as one moves away from it to the north or south, as one expects for a point source on the sky.

Congrats Ayushi on this very significant achievement for her PhD work.

UTMOST-2D has been funded through generous grants  from the Australian Research Council and the Mount Cuba Astronomical Foundation.

Congratulations to Professor Anne Green, AC

Congratulations to our friend and colleague at UTMOST, Professor Anne Green, who has been made a Companion of the Order of Australia in the Queen’s Birthday Honours for 2022,

“…for eminent service to science, particularly physics and astrophysics, as an educator and researcher, as a mentor to colleagues and students, and a role model to women.”  

Anne Green served as director of the Molonglo Radio Observatory for more than a decade, and has been instrumental in the Fast Radio Busts and pulsar timing programs we operate at UTMOST and UTMOST-2D.

She has also served as president of the Astronomical Society of Australia from 2003 to 2005.

Queen’s Birthday Honours for 2022: https://www.gg.gov.au/queens-birthday-2022-honours-list

Interview on ABC’s Radio National:

https://www.abc.net.au/radionational/programs/breakfast/trail-blazing-astronomer-receives-queens-birthday-honour/13926580

Congratulations to Professor Matthew Bailes, FAA

 

Congratulations to our friend and colleague at UTMOST, Professor Matthew Bailes, who has been elected a Fellow of the Australian Academy of Science.

Matthew instigated the UTMOST project to search for Fast Radio Bursts and do pulsar timing, as part of a presigious Australian Research Council Laureate Fellowship.

He is currently the director of the Australian Research Council‘s Centre of Excellence for Gravitational Wave Discovery (OzGrav).

His citation reads:

Matthew Bailes is an astrophysicist who has specialised in the study of pulsars, transient radio bursts and gravitation, making major contributions to establishing Australia’s high international profile in these areas. In particular, he has played a pivotal role in the development of a new branch of astrophysics, Fast Radio Bursts, guiding projects that led to Australia’s dominance of the field. He established the Swinburne University Centre for Astrophysics and Supercomputing, recognised internationally as a centre for astrophysics and virtual-reality content for public outreach.

Australian Academy of Science webpage:

https://www.science.org.au/profile/matthew-bailes

Swinburne University of Technology webpage:

https://www.swinburne.edu.au/news/2022/05/professor-matthew-bailes-elected-fellow-of-the-australian-academy-of-science/

 

 

10,000 pulsar observations

Dec 10, 2021 : UTMOST-2D has made reached a major milestone, having just made its 10,000th pulsar timing measurement.

J1056-6258, our 10,000th pulsar timing observation since beginning the UTMOST-2D campaign.

We have been timing pulsars in a new Southern Hemisphere program which kicked off at the Molonglo Radio Telescope in April 2021.

Many pulsars are observed daily, as they are in isolated regions of the sky. Other pulsars share the busy sky in the Milky Way, and are timed once a week.

We are timing just over 170 pulsars and magnetars and averaging around 70 pulsar measurements per day, so that the typical pulsar gets observed every few days.

Some of the pulsars being timed in the UTMOST-2D program

The UTMOST team (Matthew Bailes, Marcus Lower and Chris Flynn) have been working with Liam Dunn, George Howitt, Pat Meyers, Christine Yi and Andrew Melatos (University of Melbourne) on a program to measure the amplitude and rate of pulsar glitches.

We check for new glitches after every pulsar observation, using an automated glitch detection method developed at the University of Melbourne.

The program has already picked up a glitch in the bright pulsar “Vela”.

We are using the newly fully-refitted North-South arm of the telescope, installed with in-house developed receivers, using 66 sub-telescopes positioned in an array and operating fully electronically.

The program aims to achieve over 20,000 pulsar measurements per year.

We are also developing the capacity to detect Fast Radio Bursts – described in an article in Nature Astronomy in 2020.

UTMOST-2D’s pulsar timing program is a collaboration between Swinburne University of Technology, the University of Sydney and the University of Melbourne.

UTMOST-2D is science ready

20/07/2021 — the UTMOST-2D project achieved full sensitivity today — with the upgraded Molonglo telescope now seeing data across the entire installation.

UTMOST-2D is a project to return one of the two “arms” of the Molonglo telescope to full operations again , after a hiatus of over 40 years.

Molonglo is a “Mills Cross” radio telescope — consisting of two 1-mile long arms (1.6 km) arrayed North-South and East-West, and sited in a remote valley near Canberra, Australia’s capital city.

The North-South arm of the telescope last saw radio waves in the 1980s. In a project lead by Associate Professor Adam Deller, working with ARC Laureate Fellow Prof Matthew Bailes, the arm has had a complete revamp over the last three years, with completely redesigned electronics, radio receivers, antennas and digitizers installed.

The North-South arm of the telescope, now returned to full operations in the UTMOST-2D project.

Project Scientist Dr Chris Flynn commented “… seeing the data streams light up right across the new installation was very exciting, after three years of design, prototyping, manufacture and installation”.

Molonglo seen from the air in the 1960s — with the “cross” design of the two arms of 1-mile length clearly visible.

Swinburne University of Technology PhD students Cherie Day, Vivek Gupta and Ayushi Mandlik have been closely involved with the team of astronomers and engineers in the rebuild, with the design and testing work forming part of their research projects. Alphington Grammar School student Rudra Sekhri has also helped with the development cycle of the project, analysing pulsar observations to determine the system performance.

Over a dozen astronomy PhD students, postdoctoral fellows and undergraduate engineering students from around Australia have contributed to the design and construction of Molonglo for pulsar timing and FRB detection. The project has been part of Prof Matthew Bailes ARC Laureate Fellowship and A/Prof Adam Deller’s Future Fellow appointments at Swinburne University of Technology.

The redesign of the North-South arm has brought a sensitivity approximately 10 times that of the East-West arm, when compared meter-for-meter. This has been a result of substantial improvements to the polarisation, bandwidth, and noise characteristics of the new system.

An antenna and radio frequency amplifier board for the upgrade, which was purpose designed for the project

Electronic steering of the arm has also been introduced, so that its field of view can be redirected nearly instantaneously.

Engineer Angus Sutherland working on the backplane of a receiver unit in the upgraded North-South arm

Over 100 pulsars have been observed with the new system — about 150 are expected to be well visible. The aim is to make observations of 100 pulsars daily, in order to study their periodicity, gradual slow-down, and the sudden jumps called “glitches” which can be used to probe the internal structure of the neutron stars from which they arise. 

Pulse profile as a function of frequency for 81 of the more than 100 pulsars that have been observed with UTMOST-2D already.

Installation of a 9 meter long section of the North-South arm, after being fully refurbished with the new receiver system.
Single pulses being detected as a function of time, in two polarisations, on the bright pulsar Vela.

A major science goal UTMOST-2D is to find Fast Radio Bursts (FRBs) and localise them precisely on the sky. These fascinating sources are currently a major mystery in astrophysics, and finding the host galaxies from which the originate will allow us to understand their progenitors much better. UTMOST-2D will enable us to localise single bursts from FRBs at the moment of discovery. UTMOST-2D has been built with a large field of view to capture as many FRBs as possible, and will use innovative machine-learning techniques to identify them.

A Fast Radio Burst discovered by PhD student Ayushi Mandlik using the East-West arm of the telescope

More Info:

Article in Nature Astronomy by Adam Deller and Chris Flynn

Vintage telescope rebooted in the hunt for FRBs

FRB20210630A

At UTC 2021-06-30-12:48:11.2 (2021-03-30.533462963), we found a fast radio burst as part of the ongoing search program at the Molonglo telescope (UTMOST).

Molonglo is a 1.6 km long East-West array (Bailes et al 2017, PASA, 34, 45) and was operating in drift-scan mode, pointing at the meridian at the time of detection. Source localisation is excellent in Right Ascension (5 arcsec at 1-sigma) but poor in Declination (~1.2 deg at 1-sigma) (see Caleb et al 2017 MNRAS 468, 3746).

FRB20210630A was found during a blind FRB search programme in real-time using an automated GPU-accelerated/machine learning-based pipeline and the raw voltages were recorded for offline processing.

The optimal dispersion measure (DM) that maximizes the signal-to-noise ratio is: 943.7 pc cm^-3. The DM estimate of NE2001 model is ~78.7 pc cm^-3, and YMW16 model is ~59.7 pc cm^-3 at this position, resulting in an intergalactic excess of ~865  pc cm^-3. The upper limit on the DM-inferred redshift is thus z ~ 0.87.

An early estimate (lower limit) of the event’s apparent fluence is ~60 Jy ms (corrected for attenuation of the primary beam in the RA direction, but not in the Dec direction) with a detection signal-to-noise ratio = 10.

The most likely position is RA = 17:23:07.4, DEC=+07:51:42, J2000, Galactic: Gl = 29.9356 deg, Gb = 23.1882 deg. The 95% confidence localisation arc is as follows: (RA, DEC) in (hours, deg):

17.384378 5.300861
17.384511 5.661528
17.384650 6.022194
17.384789 6.382861
17.384933 6.743556
17.385078 7.104222
17.385225 7.464889
17.385375 7.825556
17.385531 8.186222
17.385686 8.546889
17.385844 8.907556
17.386006 9.268222
17.386169 9.628917
17.386336 9.989583
17.386506 10.35025

A formula describing the localisation arc is:

RA = 17.385376 + 4.22212*e-4(DEC – 7.825551) + 1.024401e-5*(DEC – 7.825551)**2

where RA is in hours, Dec is in deg, and is valid in the range Dec= [5.3, 10.35]

Follow-up observations of the FRB are encouraged.

UTMOST-2D hardware upgrade complete

 
March 2021 : the UTMOST-2D team have completed the hardware build and installation on the telescope’s North-South arm.
 
View of part of the newly upgraded North-South arm
 
The UTMOST-2D project is a major undertaking between Swinburne and Sydney Universities, and part of A/Prof Adam Deller’s ARC Future Fellowship and Prof Matthew Bailes’ Laureate Fellowship.
 
We have installed 72 “cassettes” (our basic receiver unit) and they are now fully operational, producing data into the GPU cluster on-site.
 
The last six cassettes heading out for installation, March 2021
 
Inside the RFI cabinet, showing frequency down-conversion and digitization hardware inoperation prior to sending channelised data to the GPU cluster
We are capturing around 105 Gbytes per second into a specially shielded RFI (Radio Frequency Interference) cabinet, after transporting the data optical fibre on lengths of up to 800 meters.
 
This wonderful achievement is a credit to hard work on many fronts, from electrical and mechanical engineering, electronics design prototyping and validation, hardware build and quality control and software development.
 
Bright single pulses from Vela. Similar pulses will be used to validate our FRB search pipelines
We did our first “FRB search” in April 2021, producing 250 time series streams of data in tiled beams on the sky, searching them simultaneously at high time resolution for pulses, on a test region on the bright Vela pulsar, with very encouraging results.
 
A selection of pulsars timed with the newly upgraded NS arm
We have observed more than 40 individual pulsars since handover to the astronomers, and our aim is to take this to over 150 pulsars timed daily in the coming month or so. Neutron star physics, and in particular of glitches in pulsar timing, is the major science aim with this program.
 
 
Finalising the phasing of the North-South arm is currently our focus, and being able to search for single pulses, and localise them to a few arcseconds of accuracy on the sky, is just around the corner. Host galaxies of Fast Radio Bursts to follow!
 

FRB 20210303A found by UTMOST

At UTC 2021-03-03-01:28:46.9 (2021-03-03.06165), we found a fast radio burst as part of the ongoing search program at the Molonglo telescope (UTMOST).

Molonglo is a 1.6 km long East-West array (Bailes et al 2017, PASA, 34, 45) and was operating in drift-scan mode, pointing at the meridian at the time of detection. Source localisation is excellent in Right Ascension (5 arcsec at 1-sigma) but poor in Declination (~1.2 deg at 1-sigma) (see Caleb et al 2017 MNRAS 468, 3746).

FRB210303A was found during a blind FRB search programme in real-time using an automated GPU-accelerated/machine learning-based pipeline and the raw voltages were recorded for offline processing.

The optimal dispersion measure (DM) that maximizes the signal-to-noise ratio is: 366.9 pc cm^-3. The DM estimate of NE2001 model is ~37.4 pc cm^-3, and YMW16 model is ~25.2 pc cm^-3 at this position, resulting in an intergalactic excess of ~329.6  pc cm^-3. The upper limit on the DM-inferred redshift is thus z ~ 0.33.

An early estimate (lower limit) of the event’s apparent fluence is ~37.8 Jy ms (corrected for attenuation of the primary beam in the RA direction, but not in the Dec direction) with a detection signal-to-noise ratio = 21.8.

The most likely position is RA = 22:15:52.3, DEC=-46:05:32, J2000, Galactic: Gl = 350.7129376 deg, Gb = -53.989646 deg. The 95% confidence localisation arc is as follows: (RA, DEC) in (hours, deg)

22.273572 -50.44886

22.272372 -49.948111

22.271211 -49.447389

22.270081 -48.946639

22.268983 -48.445889

22.267917 -47.945111

22.266881 -47.444361

22.265875 -46.943611

22.264897 -46.442833

22.263947 -45.942056

22.263025 -45.441278

22.262128 -44.940500

22.261253 -44.439722

22.260406 -43.938944

22.259581 -43.438139

22.258778 -42.937361

22.257997 -42.436556

22.257236 -41.935750

A formula describing the localisation arc is:

RA = 22.264419 – 1.911549e-3 * (DEC+ 46.192395) + 5.435355e-05*(DEC +46.192395)**2

where RA is in hours, Dec is in deg, and is valid in the range Dec= [-40, -52]


Follow-up observations of the FRB are encouraged.