2024-02-15

Owned by Gemma Elizabeth Anderson
Feb 15, 2024
3 min read

Minutes for MWA Transients meeting

Attendees: Gemma Anderson, Steve Prabu, Natasha Hurley-Walker, Sam McSweeney, Kat Ross, Stephen Ord, Danny Price, Laura Driessen, Csanad Horvath

Declined due to other commitments: Clancy James

Agenda (see email sent on 14 Feb 2024)

  • Steve Prabu: MWA observations of a cometary trail and meteor shower discovery

  • Natasha Hurley-Walker: SC1 MWA Transients update

  • General updates and paper plans

  • Project discussions

Meeting Minutes

Steve Prabu: Meteor shower discovered using MWA

Slides: https://docs.google.com/presentation/d/1J5Vkc6fILOZBG3EZc46t6DIYsvPxt0qJnlddh7JgzTI/edit?usp=sharing

  • Comet 46P - theory predicted Earth should go through the comet trail on 12 Dec 2023

  • The “radiant” was near WA

  • Use MWA as a passive radar to detect meteor trails - FM reflected by plasma trail

  • 2 lots of 12 hr obs on the day and the day after. This later observation to get a baseline on false positives. Used Hex Configuration.

  • Detected meteors in candidates moving away from the radiant. 

  • Hourly rate will inform about the population in the comet trail when can access ASVO again.

  • Reduction of events in second obs will give baseline noise. 

  • Remove chromatic artifacts by imaging on FM signal and then a little bit off that frequency to remove backgrounds.

  • Haven’t looked at polarisation

  • Group from Sydney and Canberra have published optical observations taken in Eastern Australia. Paper came out yesterday.

  • Cross-match between MWA with Optical? MWA is more sensitive but not sure if horizons cross match as meteors are within 80 km altitude. 

 

Natasha: MWA Transients projects from SC1 research group

Slides: https://docs.google.com/presentation/d/1YKWeNidG9kskJ-tUyvpxXJkknW6_6NDbdviqnrJ6ZHM/edit?usp=sharing

  • Galactic Plane Monitor (G0080)

    • Aim was to look for long period radio transient (4s to 3 months) - Hurley-Walker et al. (2023)

    • Plans for survey description and data release. Pawsey prevents data processing.

    • Averaged together for SNR search (Silvia Mantovanini)

    • Hourly to day variability searches - 4 varying sources, which are eclipsing binary MSPs (Flora Petrou). Follow-up with other instruments including ASKAP VAST. No pulsations yet but associated with gamma-ray sources detected by Fermi.

    • Stokes V search (Yong Low) - PSRs and polarised AGN. Then transient search will occur.

    • Want to reprocess GPM before getting another epoch. 

    • Plans to propose for a second epoch of GPM when MWA is next in the extended configuration. This requires Pawsey to be stable.

  • GLEAM-X (G0008) blind search

    • 4s to 4 weeks (5 min timescales)

    • DR2

    • Lots of transient cubes

    • New PSR discovered in image plane - 1s period and far of GP (Jared Moseley)

    • Variability of peak spectrum sources (Kat Ross)

  • Other papers

    • Polarisation properties of ULP radio transients (Sam McSweeney)

    • Eclipsing binary MSPs detected in VAST (Flora Petrou)

    • AR Sco like object J1912 - white dwarf-M dwarf binary where WD produces pulsations - first detection of such objects at Low Freq 

  • New ASKAP transients - Both CRACO and VAST making detections

    • CRACO has its own computer system separate from Pawsey and is detecting transients that VAST has seen. Unfortunately, Pawsey issues causing problems with VAST processing so CRACO could scoop VAST.

    • Natasha plans an MWA proposal to follow-up these objects

    • Rapid follow-up

    • Mostly long-period radio transients

 

Gemma: Transient triggering

  • Update on Fan Xu processing dynamic spectra of MWA VCS triggers on long GRBs to search for FRB-like signals

  • MWA is set up to trigger on Gravitational Wave-detected BNS mergers. MWA can sit idle pointing at a patch of sky and can then do a voltage dump. This mode could be useful for other types of transients detected by ASKAP (shadowing ASKAP).

    • Laura says there is pressure for ASKAP to broadcast their pointing so we can do shadowing.

  • Triggering software needs significant upgrades. MWA triggering for GW BNS mergers is currently broken. Need to modularise triggering software so is distinct from the web application. This will allow more broader use. Requires another ADACS proposal. Please talk to me if this interests you, particularly for ASKAP triggering.

 

Discussions:

  • Follow-up of CRACO and/or VAST transients using MWA. Gemma proposed ASKAP shadowing similar to current LIGO-Virgo-KAGRA shadowing so can perform a voltage dump.

    • We need to place pressure on ASKAP to broadcast its pointing position

  • Need to modularise triggering software so can ingest and filter CRACO and VAST transients. Talk to Gemma if interested as this will require another ADACS proposal.

  • We need to create a transients-specific Wiki page that lists active and planned transient projects so that everyone is aware of what people are working on.

  • Agreed on quarterly meetings for the MWA Transients SWG.