Category Archives: Uncategorised

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.

North-South arm detects single pulsar pulses for the first time

We had a major milestone at Molonglo last week — we made the first detections of single pulses from a pulsar on the upgrade of the North-South arm of the telescope.

Data taken as part of the commissioning of the hardware show a neat train of single pulses from Vela — the brightest pulsar in the Southern Hemisphere.

Individual pulses from Vela on two poles — a first for the North-South arm. Both radio polarisations are seen as a function of frequency (y-axis) and time (x-axis). The pulses can be clearly seen in the time series data below each image.

Pulses like these are similar to those seen from Fast Radio Bursts (FRBs) — and will allow us to check that we can pinpoint where they are coming from on the sky. We expect to be able to localise the sources to a few seconds of arc in both the East-West and North-South direction, and thus find the distant galaxies from which FRBs originate.

The hardware upgrade is continuing, with about half the final hardware expected to be in position by the end of 2020.

North-South arm upgrade update

The upgrade of the North-South arm of the Molonglo telescope — being carried out so that we can localise Fast Radio Bursts to their host galaxies — is well under way.

Five of the 11 “modules” (9 meter long receiver elements) are now in place on the arm, and data taking on two of them in full operation.

All five are expected to be taking data by the end of October 2020.

 
Dave Temby and Angus Sutherland doing final adjustments on a newly installed module.
 
Two solar powered battery units are in full operation powering the newly installed modules.

Five pulsars have been observed with the system to date — Vela, J0837-4135, J1644-4559, J1752-2806 and J1243-6423.

Profile of the bright Southern pulsar J1644-4559, as seen with a small section of the NS-arm at Molonglo.

Resurgence in the radio flux of the magnetar XTE J1810-197

Following its radio revival in late-2018 (Levin et al. 2019) we have performed regular timing observations of the magnetar XTE J1810-197 with the Molonglo Observatory Synthesis Telescope as part of the UTMOST project (Bailes et al. 2017).

A single bright pulse from XTE J1810-197 which reached S/N ~100.

During a recent observation on UTC 2020-06-22-14:02:29, we measured a period averaged flux density of 35 +/- 7 mJy at 835 MHz via the radiometer equation. This is approximately a factor of 2.7 times higher than the flux density of 13 +/- 5 mJy measured 5 days earlier on UTC 2020-06-17-14:22:07, and a factor of ~5 times higher than observations in February 2020. The radio intensity appears to have decayed to flux densities between 15-20 mJy in the days following the resurgence. All observations were calibrated to the flux density of the high dispersion measure pulsar PSR J1644-4559.

Flux density measurements for XTE J1810-197, showing a bright outburst in the radio flux.

Bright single pulses with peak flux densities up to 50 +/- 15 Jy were detected in most post-resurgence observations.

Further details are available in an Astronomer’s Telegram.

Molonglo telescope’s two arms working in unison again

June 2020 : both arms of the Molonglo telescope have been brought into simultaneous operation for the first time in decades, as part of the hunt for host galaxies of Fast Radio Bursts.

Molonglo consists of two “arms” — each 1.6 km long and 11 meters wide, and aligned in the North-South and East -West directions, in a flat valley near the town of Bungendore in southern New South Wales.

The East-West arm of the telescope has been in full operation after a major upgrade 5 years ago, in a collaboration between the Swinburne University of Technology and the University of Sydney.

In 2019-2020, the long dormant North-South arm is being brought back into full operation in the UTMOST-2D project.

Observations of a bright quasar — a black hole in the center of a distant galaxy — showed a strong signal on both arms in first tests of the newly mounted North-South arm receivers in June 2020.

The quasar shows up in the signal collected on both arms as a strong peak as the source transited overhead, in observations coordinated by PhD student Vivek Gupta.

The observation shows that the project is well on the way to being able to make images of a few square degree region of the sky (about 10 times the size of the full Moon) — something that has not been done at Molonglo since the SUMSS survey in the 1990s — and eventually to localise FRBs to their host galaxies.

Congrats to the whole UTMOST-2D team for this milestone achievement!

A 9 meter long element of the North-South arm upgrade being positioned on the telescope.

FRB200607 found by UTMOST

At UTC 2020-06-07-10:37:21.7 (2020-06-07.442612269), we found a bright fast radio burst as part of the ongoing search program (UTMOST), at the Molonglo telescope.

Molonglo is a 1.6 km long East-West array (Bailes et al 2017, PASA, 34, 45) 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).

FRB200607 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: 466.9 pc cm^-3. The DM estimate of NE2001 model is ~30 pc cm^-3, and YMW16 model is ~25 pc cm^-3 at this position, resulting in an intergalactic excess of ~439 pc cm^-3. The upper limit on the DM-inferred redshift is thus z ~ 0.40.

An early estimate (lower limit) of the event’s apparent fluence is ~ 51 Jy ms (corrected for attenuation of the primary beam in the RA direction, but not in the Dec direction), width ~ 1.3 ms, with a detection signal-to-noise ratio = 41.

The most likely position is RA = 13:41:30.65, DEC = -05:08:24.1, J2000, Galactic: 325.4 deg, Gb = 55.5 deg. The 95% confidence localisation arc is as follows: (RA, DEC) in (hours, deg)

A formula describing the localisation arc is:

RA = 13.691826 + 1.106710e-04*(DEC + 5.204167) + 7.531360e-06*(DEC + 5.204167)**2

13.691603 -7.608750
13.691628 -7.288139
13.691653 -6.967528
13.691681 -6.646917
13.691711 -6.326306
13.691742 -6.005694
13.691775 -5.685083
13.691808 -5.364472
13.691844 -5.043861
13.691881 -4.723250
13.691919 -4.402639
13.691958 -4.082028
13.692000 -3.761417
13.692044 -3.440806
13.692089 -3.120194
13.692136 -2.799583

where RA is in hours, Dec is in deg, and is valid in the Dec range [-7.6,-2.8]

Follow-up observations of the FRB are encouraged. 

FRB200514 found by UTMOST

At UTC 2020-05-14-05:40:45.7 (2020-05-14.23664005), we found a fast radio burst as part of the ongoing search program (UTMOST), at the Molonglo telescope.

Molonglo is a 1.6 km long East-West array (Bailes et al 2017, PASA, 34, 45) 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).

FRB200514 was found during a blind FRB search programme in real-time using an automated GPU-accelerated/machine learning-based pipeline. Unfortunately, raw voltages were not recorded and so we were unable to analyse the FRB at native time resolution.

The optimal dispersion measure (DM) that maximizes the signal-to-noise ratio is: 349.4 pc cm^-3. The DM estimate of NE2001 model is ~85.3 pc cm^-3, and YMW16 model is ~228.2 pc cm^-3 at this position, resulting in an intergalactic excess of ~193 pc cm^-3. The upper limit on the DM-inferred redshift is thus z ~ 0.18.

An early estimate (lower limit) of the event’s apparent fluence is ~11 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 = 9.8.

The most likely position is RA = 07:01:00.55, DEC =-45:54:25.0, J2000, Galactic: Gl = 256.1140 deg, Gb = -17.5560 deg. The 95% confidence localisation arc is as follows: (RA, DEC) in (hours, deg).

7.008703 -50.264306
7.009736 -49.763472
7.010744 -49.262639
7.011722 -48.761806
7.012675 -48.260944
7.013600 -47.760111
7.014503 -47.259250
7.015381 -46.758417
7.016236 -46.257556
7.017067 -45.756694
7.017878 -45.255833
7.018669 -44.754972
7.019439 -44.254111
7.020186 -43.753222
7.020919 -43.252361
7.021631 -42.751500
7.022325 -42.250611
7.023000 -41.749750

A formula describing the localisation arc is:

RA = 7.016655 + 1.673513e-3*(DEC + 46.007086) – 4.428062e-05*(DEC + 46.007086)**2

where RA is in hours, Dec is in deg, and is valid in the range Dec= [-50.3,-41.7]

Follow-up observations of the FRB are encouraged.

FRB200508 found by UTMOST

At UTC 2020-05-08-07:42:09.5 (2020-05-08.320943), we found a fast radio burst as part of the ongoing search program (UTMOST), at the Molonglo telescope.

Molonglo is a 1.6 km long East-West array (Bailes et al 2017, PASA, 34, 45) 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).

FRB200508 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: 629 pc cm^-3. The DM estimate of NE2001 model is ~144.9 pc cm^-3, and YMW16 model is ~248.2 pc cm^-3 at this position, resulting in an intergalactic excess of ~433 pc cm^-3. The upper limit on the DM-inferred redshift is thus z ~ 0.39.

An early estimate (lower limit) of the event’s apparent fluence is ~29.7 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 = 14.33.

The most likely position is RA = 09:01:32.39, DEC =-65:35:42.7, J2000, Galactic: Gl = 282.02095755 deg, Gb = -12.5633715542 deg. The 95% confidence localisation arc is as follows: (RA, DEC) in (hours, deg).

9.083156 -69.939722
9.075233 -69.440667
9.067694 -68.941528
9.060517 -68.442306
9.053669 -67.943000
9.047136 -67.443611
9.040892 -66.944167
9.034922 -66.444667
9.029211 -65.945083
9.023739 -65.445472
9.018492 -64.945806
9.013458 -64.446083
9.008628 -63.946306
9.003986 -63.446500
8.999522 -62.946667
8.995228 -62.446778
8.991094 -61.946833
8.987114 -61.446889

A formula describing the localisation arc is:

RA = 9.026409 – 1.1189104e-2*(DEC + 65.69456) + 4.823077e-4*(DEC + 65.69456)**2

where RA is in hours, Dec is in deg, and is valid in the range Dec= [-61.5, -70]

Follow-up observations of the FRB are encouraged.