All posts by cflynn

FRB170922 – UTMOST finds the widest FRB yet

On 2017-09-22-11:23:33.4 UTC (2017-09-22.4746921296), UTMOST found a new FRB as part of the ongoing search program at the Molonglo Radio Telescope (see Bailes et al. 2017, arxiv.org/abs/1708.09619). This is the fifth Molonglo FRB overall (See ATel #10697 and Caleb et al. 2017, MNRAS, 468, 3746).

The optimal dispersion measure (DM) that maximizes the signal-to-noise ratio is: 1111 pc cm^-3, which is substantially in excess of the Galactic DM as estimated by the NE2001 (www.nrl.navy.mil/rsd/RORF/ne2001/) model (~ 45 pc cm^-3) and the YMW16 (www.xao.ac.cn/ymw16/) model (~ 33 pc cm^-3). The upper limit on the DM-inferred redshift is thus ~0.8. The S/N in the detection beam is 22, and an early estimate of the event’s fluence is ~ 60 +/- 15 Jy ms. The FRB’s estimated width (full width half power) is 26 ms.

Source localisation is excellent in the Right Ascension (~ 5 arcsec at 1-sigma) but poor in Declination (~1.2 deg at 1-sigma). The most likely position is RA = 21:29:50.61, DEC = -07:59:40.49, J2000, Galactic: Gl = 45.1°, Gb = -38.7°. The 95% confidence localisation arc is as follows:

21:29:50.50 -10:21:32.1
21:29:50.48 -09:52:40.9
21:29:50.49 -09:23:49.8
21:29:50.52 -08:54:58.6
21:29:50.56 -08:26:07.4
21:29:50.62 -07:57:16.2
21:29:50.63 -07:52:27.7
21:29:50.71 -07:23:36.5
21:29:50.81 -06:54:45.3
21:29:50.92 -06:25:54.1
21:29:51.06 -05:57:03.0
21:29:51.21 -05:28:11.8

A formula describing the localisation arc is:

RA = 21.500702 + 3.753954e-4*(DEC – 7.994579) + 1.053305e-5*(DEC – 7.994579)^2

Where RA is in hours, DEC is in deg, and is valid in the DEC range [-12.36,-3.63]

Follow-up observations of the FRB are encouraged.

 

Screen Shot 2017-10-20 at 10.13.50 AM

 

atelfrb5.localisationThe blue cross is the telescope pointing center; the green cross is the highest probability position of the FRB, and the line indicates the localisation arc.  Several low DM pulsars in the field of view are also seen in grey.

 

 

 

 

 

 

CAASTRO / Swinburne to host FRB workshop

On February 14-16, 2018, Swinburne University of Technology will host an international workshop entitled “FRB2018: Finding and Understanding Fast Radio Bursts“. The workshop will cover a broad range of FRB instrumentation and science, but with a particular focus on directions over the coming ~5 years, as the number of detected FRBs expands rapidly and their localisation becomes commonplace.

The key themes of the workshop will be:

Understanding FRB progenitors and their host environments.

This requires:
Real-time detection and localisation with interferometers.

Can we achieve these goals more effectively via:

Synergies between current facilities and/or identifying opportunities for existing facility upgrades?

Leading FRB researchers from FRB collaborations world-wide have been invited to present recent results and future directions, offering an opportunity to build and extend collaborations.

Registration is now open.

FRB170827 — first FRB detection with an automated system

On 2017-08-27-16:20:18 UTC (2017-08-27.68076389), we found a bright burst as part of the ongoing FRB search program (UTMOST), at the Molonglo telescope.

Molonglo is a 1.6 km long East-West array (see Bailes et al 2017) and was operating in drift-scan mode with pointing centred on 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).

FRB170827 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. Using 300 ms of voltage data, we improved localisation of the FRB by repointing the array to different directions and maximising S/N.

The most likely position is RA = 00:49:18.66, DEC = -65:33:02.3, J2000. The optimal dispersion measure (DM) that maximizes the signal-to-noise ratio is: 176.4 pc cm^-3. The DM estimate of NE2001 model is ~37 pc cm^-3, and YMW16 model is ~27 pc cm^-3 at this position, resulting in an intergalactic excess of ~145 pc cm^-3, the lowest known. The upper limit on the DM-inferred redshift is thus ~0.15. An early estimate of the event’s fluence is ~ 20 Jy ms, width ~ 395 us, with a signal-to-noise ratio > 90.

The 95% confidence localisation arc is as follows:

00:50:09.05 -67:54:48.9
00:50:01.57 -67:35:35.5
00:49:54.31 -67:16:22.2
00:49:47.25 -66:57:08.7
00:49:40.40 -66:37:55.3
00:49:33.74 -66:18:41.9
00:49:27.27 -65:59:28.4
00:49:20.98 -65:40:14.9
00:49:14.85 -65:21:01.4
00:49:08.90 -65:01:47.8
00:49:03.09 -64:42:34.3
00:48:57.45 -64:23:20.7
00:48:51.95 -64:04:07.1
00:48:46.59 -63:44:53.5
00:48:41.36 -63:25:39.9
00:48:37.53 -63:11:14.7

A formula describing the localization arc is: DEC = -60.71088 -253.7786*(RA – 0.8) + 1480.220*(RA – 0.8)^2.
Where RA is in hours, Dec is in deg, and is valid in the RA range [0.84, 0.81].

Note that this localisation arc crosses through the SMC (Small Magellanic Cloud) if extended a further ~6 degrees, where we expect a beam attenuation of ~15 dB. We note that the measured DM of the FRB is similar to SMC pulsars.

frb170827

Screen Shot 2017-08-31 at 7.51.30 pm

UTMOST on the Science Show

Screenshot_2017-05-02_14-14-15

UTMOST PhD student –  and now a postdoc – Manisha Caleb, has appeared on the Science Show on the Australian national broadcaster (ABC) talking about the 3 Fast Radio Bursts (FRBs) she discovered with the Molonglo telescope.

UTMOST is an interferometer and places the point of origin of the FRBs well beyond the Earth — at least 10,000 km away.

http://www.abc.net.au/radionational/programs/scienceshow/

Link to the audio

For our news item on this story, see here

 

Mysterious bursts of energy do come from outer space

Fast Radio Bursts present one of modern astronomy’s greatest mysteries, what or who(!) in the Universe is transmitting short bursts of radio energy across the cosmos?

Molonglo_FRB

Manisha Caleb, a PhD candidate at Australian National University/Swinburne University of Technology and the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), has confirmed that the mystery bursts of radio waves that astronomers have hunted for ten years really do come from outer space.

Ms Caleb worked with Swinburne and University of Sydney colleagues to detect three of these Fast Radio Bursts (FRBs) with the Molonglo radio telescope 40 km from Canberra.

Discovered almost 10 years ago at CSIRO’s Parkes radio telescope, Fast Radio Bursts are millisecond-duration intense pulses of radio light that appear to be coming from vast distances. They are about a billion times more luminous than anything we have ever seen in our own Milky Way galaxy.

 

Screenshot - 030417 - 23:46:49

The profiles of the 3 radio bursts are shown at left as a function of the radio frequency of detection, and at right as a function of time for nearby locations on the sky. The presence of the bursts in just 1 or 2 of these adjacent locations demonstrates they are originating from more than 10,000 km away. Figure from the paper by Caleb et al 2017. 

One potential explanation of the mystery is that they weren’t really coming from outer space, but were some form of local interference tricking astronomers into searching for new theories of their ‘impossible’ radio energy.

Perhaps the most bizarre explanation for the FRBs is that they were alien transmissions,” says ARC Laureate Fellow Professor Matthew Bailes from Swinburne.

Conventional single dish radio telescopes have difficulty establishing that transmissions originate beyond the Earth’s atmosphere,” says Swinburne’s Dr Chris Flynn.

In 2013 CAASTRO scientists and engineers realised that the Molonglo telescope’s unique architecture could place a minimum distance to the FRBs due to its enormous focal length. A massive re-engineering effort began, which is now opening a new window on the Universe.

Ms Caleb’s project was to develop software to sift through the 1000 TB of data produced each day. Her work paid off with the three new FRB discoveries.

It is very exciting to see the University of Sydney’s Molonglo telescope making such important scientific discoveries by partnering with Swinburne’s expertise in supercomputing”, says Professor Anne Green of the University of Sydney.

Over the next two years the telescope will be improved even more, thanks to further funding from the Australian Research Council, gaining the ability to localise bursts to an individual galaxy.

Figuring out where the bursts come from is the key to understanding what makes them. Only one burst has been linked to a specific galaxy,” Ms Caleb says. “We expect Molonglo will do this for many more bursts.”

A paper on the discovery “The first interferometric detections of Fast Radio Bursts” has been accepted for publication in Monthly Notices of the Royal Astronomical Society.

Online at https://arxiv.org/abs/1703.10173

 

National Youth Science Forum students visit UTMOST

The National Youth Science Forum (NYSF) hosts 12 day residential program for students entering year 12 who are passionate about science, technology, engineering and maths (STEM).

On 6th and 21st Jan, about 24 students in the 2017 program visited Molonglo and toured the telescope site, the supercomputing facilities and watched live operations observing pulsars and searching for Fast Radio Bursts.


Screenshot - 200217 - 22:15:19

  • Tim Bateman spoke to the students on the real world radio engineering and high speed data processing requirements of an active research site.
  • Ding Yan talked about the motivation to study engineering (and which kind!), the path through university and search tips for employment.
  • Swinburne reaserch Dr. Chris Flynn demonstrated the telescope live and talked about the science of pulsars and fast radio bursts.
  • Two Swinburne students Shivani Bhandari and Kathryn Plant spoke about their projects to find Fast Radio Bursts.
  • Raj Biswas, who is working on a major refit of the telescope, spoke about his project to measure the amount of radio interference on the site.

 

Screenshot - 200217 - 22:15:39

High spectral resolution mode implemented at UTMOST

Dec 2106 : UTMOST is hunting for Fast Radio Busts — FRBs — mysterious flashes of radio energy which last only for a few milliseconds which appear to have come to us from billions of light years away.

The telltale sign that the bursts come from so far away is the “swept signal” they show. For FRBs, this is seen as the higher frequency radio waves arriving at the telescope before the lower frequency waves.

Screenshot - 310515 - 11:39:06

In swept radio signals from FRBs, higher frequencies arrive at the telesocpe detectors before lower frequencies do — with a delay of as much as a second or more. Presently, this effect — known as the FRB “dispersion measure” — is our best means of estimating the distance to the source.  

As a direct consequence, better frequency resolution at the telescope means that we are able to detect FRBs with higher dispersions more easily.

UTMOST has spent the last two months upgrading its frequency resolution by a factor of 8 — a very significant improvement which could improve our ability to detect FRBs by a factor of 2 or 3 — depending on their intrinsic properties.

Congratulations on the huge effort by Andrew Jameson and Tim Bateman to get this new mode of operation rapidly written and commissioned during the last two months.

 

 

 

 

 

UTMOST welcomes Adam Deller and Jamie Tsai

 

UTMOST is delighted to welcome two new members — both of whom arrived at Swinburne this week.

Adam Deller : Adam is an ARC Future Fellow, who rejoins Swinburne as a staff member after spending about a decade overseas (in the US and Netherlands). Adam did his PhD at Swinburne and it’s great to have him back. He has an ARC grant to work on FRB localisation in a project called UTMOST-2D — which will bring North-South detections back at Molonglo.

Jr-Wei “Jamie” Tsai : Jamie joins us as a postdoctoral fellow (funded by Matthew’s Laureate Fellowship), and comes to us from Virginia Tech, where he has worked on pulsars and transients with the Long Wavelength Array, as well as giant pulses from pulsars, cosmology and the early universe, and radio followup at low frequencies of gravitational waves.

UTMOST’s Matthew Bailes to lead the ARC Centre of Excellence OzGrav

UTMOST project leader Professor Matthew Bailes has been awarded a presitigious grant by the Australian Research Council to lead a Centre of Excellence on Gravitational Waves

http://www.swinburne.edu.au/news/latest-news/2016/09/new-arc-centre-of-excellence-for-gravitational-wave-discovery-announced.php

20160908_160853

UTMOST team members Tim Bateman, Dave Temby, Ding Yan, Chris Flynn (taking photo), Vivek Venkatraman Krishnan and Kathryn Plant enjoying a mudcake in celebration with Matthew.

Senior undergradute students from Nanjing visit Molonglo

UTMOST has hosted a site visit by Wenhao Li, Hao Qiu, Haobing Wang, and Yunkai Wang (University of Nanjing) and Jan Hamann (University of Sydney).  The students are visiting the University of Sydney for two months as part of an exchange program for undergrads between China and Australia.

They visited the Parkes Radio Telescope (pictured) and the Molonglo Radio Observatory on Thurs/Friday 28-29/July.

image1

At Molonglo, the students saw the telescope in a special mode of operation as it was part of a global observing program, involving 12 telescopes, to search for optical counterparts to Fast Radio Bursts, and radio counterparts to very faint optical transients.

cmvisit2

We had the opportunity to show them the telescope in action, as well as data aquisition and processing with radio transients being detected in near real time, as well as discuss our science program, and research und study in Australia with UTMOST staff members Chris Flynn, Tim Bateman and postdoctoral fellow Stefan Oslowski and PhD student Manisha Caleb (ANU).

cmvisit1