Transients and
Pulsars with
MeerKAT

Welcome to the TRAPUM project on MeerKAT.

Image provided by SKA South Africa shows MeerKAT in 2016.

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Latest TRAPUM news

TRAPUM Survey Goals

Utilising the power of MeerKAT, TRAPUM will discover numerous new pulsars and transient events in order to expand our knowledge of the populations of sources which emit at radio wavelengths on timescales ranging from microseconds to seconds. The discovery and continued study of these objects provides a powerful tool to improve our understanding of physics in extreme environments.

Science Themes

The science case for TRAPUM covers a broad range of neutron-star, galactic and extra-galactic astrophysics as well as gravitational and high-energy physics. The primary science objectives are:

  • Increasing the sample size of all types of radio pulsars, constraining the birth rates and distribution of neutron stars in the Galaxy.
  • Exploring the properties and evolution of globular clusters by discovering and timing many new puilsars and transients associated with them.
  • Investigate the dependence of the pulsar and fast transient populations on host galaxy properties, by searching for them in external galaxies.
  • Probe the Galactic centre, by discovering pulsars interacting with Sgr A*, dark matter, interstellar plasma and stellar populations in the central region of the Galaxy.
  • Improve our understanding of gravity, by discovering relativistic binaries and millisecond pulsars suitable for gravitational wave experiments.
  • Expand the searchable parameter space for fast transient radio sources, enabling study of the most energy-dense events in the Universe, and potentially identify electromagnetic counterparts to gravitational radiation events.
  • Search for high red-shift radio bursts and use them to refine cosmology.

supernova
The Cassiopeia A supernova remnant.
(Chandra/NASA)

This science-impact driven project plays to the strengths of the MeerKAT telescope in time-domain astrophysics, the excellent sensitivity allows for the detection of these very faint radio sources, and the high instantaneous spatial resolution enables localisation of events that last for a fraction of a second. This capability for localisation of radio transients is critical to the using and understanding the exotic and currently unknown origins of many of these events.

These science goals will be achieved through a series of targeted searches, capitalising on the sensitivity of MeerKAT to make significant new discoveries.

Read more about the survey plan below

Survey Plan

Targeted pulsar searches of SNRs, PWNe, and unidentified Fermi gamma-ray sources
Supernova remnants (SNRs), pulsar wind nebulae (PWNe) and Fermi gamma-ray sources host, arguably, some of the most interesting radio pulsars. The discovery of a radio pulsar coincident with a SNR/PWN/gamma-ray source is crucial for understanding the energy budget of such systems and, vice-versa, multi-wavelength counterparts provide substantially more context for understanding the nature of the radio pulsar itself. Discovering young pulsars associated with SNRs or PWNe is important for understanding the Galactic neutron star formation rate, the nature of the supernova explosion, and the injection of high-energy particles into the interstellar medium. Unidentified Fermi gamma-ray sources provide a treasure map for deep pulsar searches and, for example: the millisecond pulsars (MSPs) found can probe accretion physics (e.g. "transitional" MSPs), provide new precision timers for the International Pulsar Timing Array, as well as identify exotic binaries capable of testing gravity and/or constraining the neutron star equation of state.

Globular Cluster Searches
Globular clusters (GCs) harbor a very large number of MSPs per unit stellar mass compared with the Galactic plane. This is because the dense stellar environments in the cores (104 − 103 M pc−3) promote collisions and exchange interactions that create binaries capable of recycling old neutron stars to become MSPs. A total of 146 pulsars have been discovered in globular clusters to date, the majority of them MSPs. Some clusters are spectacularly prolific: Terzan 5 and 47 Tuc host 34 and 25 pulsars respectively. Surveying them with MeerKAT therefore has the potential for rich and rapid reward.

Approximate fraction of observation time spent on each survey component.
Target Fraction
SNRs,PWNe,TeV & γ-ray 10.6%
Globular Clusters 7.9%
Nearby Galaxies 5.5%
"Fly's Eye" Transients 17.8%
Repeat Fast Radio Bursts 4.9%
Galactic Census & Plane 40.7%
Follow up pulsar timing 12.4%

Extragalactic pulsar and transient searches
MeerKAT has the sensitivity to reveal new pulsars and fast transients beyond the Milky Way. Studying extragalactic pulsars we can help us understand the relationship between the formation of neutron stars and their environement. Only 29 such extragalactic pulsars are known, and all are located in the Magellanic Clouds. Using MeerKAT we will reach a survey sensitivity beyond anything other survey performed before to study not only the Magellanic Clouds but also other galaxies of the local group and beyond. Detecting pulsars and fast transients outside the local group, and determining how much their signal was dispersed by the intergalactic medium will begin to provide us with the tools needed to probe the structure of the intergalact medium. Moreover, understanding the nearby population of giant pulse emitting, or radio-emitting magnetars, has gained even more importance given that they are proposed models for at least some of the fast radio bursts (FRBs) and this is further highlighted by the recent discovery of a repeating FRB.

Using pulsars to probe gravity, dark matter & stellar populations in the Galactic Centre
The discovery of a pulsar closely orbiting the super-massive black hole at the centre of our Galaxy, Sgr A*, would not only supersede all previous tests of General Relativity (GR) in the strong-field regime, it would also enable the space-time around a rotating black hole to be probed with high precision and in a model independent fashion; for example, allowing tests of the cosmic censorship conjecture and the no hair theorem. Such a "laboratory" for precision tests of GR and black hole physics would be unrivalled by any future astrometric measurements of the S-Stars. Furthermore, mass-segregation in the central parsec may also lead to the presence of additional gravitational testbeds in the form of stellar-mass pulsar black hole binaries.

Towards a Galactic census
The known pulsar population has increased by about 400 sources, or about 20% since 2010. This increase has been achieved by improving techniques and methods on existing telescopes, and new telescopes like LOFAR. With new pulsars, new science is enabled, resulting from the bulk properties of the discovered population, from discovered pulsars being probes of the surrounding medium, or by being exceptional laboratories for testing theories of gravity. With MeerKAT being many times more sensitive than Parkes, the previous largest dish used for pulsar searches in the South, the search for pulsars in the Galatic plane - the birth place of pulsars - provides a significant and rare sharp increase in sensitivity for exploring the dynamic radio sky. The 400 beams combined with much increased sensitivity mean a significant increase in search capability, making a large-scale survey with MeerKAT not only possible, but in fact mandatory. The TRAPUM survey will be the most sensitive survey of the inner Galactic plane ever conducted, being the benchmark and testbed for the later SKA surveys.

Fast transients – discovering and understanding source populations
The fast transient landscape has changed dramatically since 2010 with the discovery of the population of FRBs which are exciting in themselves but also highlighted that the dynamic radio sky is still largely unexplored and with potentially more rich rewards. MeerKAT’s unique combination of wide FoV, high sensitivity, and wide bandwidth will provide supreme sensitivity per unit time and frequency making it a prime instrument to study the transient sky. We will carry out commensal observing for fast transients on all of the TRAPUM observations proposed here: Galactic plane and Centre, High energy point sources and SNRs, globular clusters and external galaxies. We also consider here the exciting possibility of the detectability of Lorimer-burst brightness (30 Jy and >400-σ) FRBs with a MeerKAT Fly’s Eye experiment (i.e. single-dish observing). In Fly’s Eye mode, MeerKAT will instantaneously cover 0.8 × 64 = 51.2 deg2, and will therefore be able to detect rare, bright transient events. Finally, alongside the sheer increase in the number of FRBs detected the other major development is that FRB 121102 has exhibited repeated bursts seen both at Arecibo and with the GBT (Scholz et al. 2016). These bursts are characterised by a range of flux density and strongly varying spectral indices and a wide range of modulation indices that have so far prevented the detection of any possible underlying periodicity. The repeating nature indicates that they are not from a cataclysmic event and suggest that at least some FRBs are possibly associated with neutron star origins, like magnetars or giant pulses from radio pulsars. Crucial to understanding what this means for the FRB population as a whole is determining if all FRBs repeat or whether there are multiple classes.

Follow Up Timing
After the initial discovery of a pulsar, most of the science can only be extracted by follow-up timing. Therefore, it is an absolutely crucial aspect of characterising the new TRAPUM pulsars to get a timing solution. In its most basic form this means getting an accurate position, period and period derivative so that one can compare the pulsar properties with the known pulsar population, and in particular for those sources that are found in our targeted searches we are interested in knowing their characteristic ages and their spin-down energies to compare with the SNRs and high energy emission, for example. We are also interested in determining whether or not the sources are potentially high precision timers and so useful for gravitational wave searches, and/or members of binary systems and so potentially useful for mass determinations or tests of gravity.

TRAPUM News

Telecon

2016-08-04

We held a telecon to discuss team planning matters the minutes can be found here. The next telecon will be in early October.

Proposal Submitted

2016-06-19

A proposal describing the updated science case and observing request for TRAPUM has been submitted.

Website created

2016-06-16

The TRAPUM website, trapum.org, has been launched. Publications, data releases and survey status updates will appear here once the survey is underway.

Team members

PIs

  • Ben Stappers (UK)
  • Michael Kramer (DE)

Project Scientist

  • Ewan Barr (DE)

Co-Is

  • Rene Breton (UK)
  • Markus Böttcher (SA)
  • Geoffery Bower (US)
  • Sarah Buchner (SA)
  • Marta Burgay (IT)
  • Francesca Calore (NL)
  • David Champion (DE)
  • Weiwei Chen (DE)*
  • Julia Deneva (US)
  • Ralph Eatough (DE)
  • Chris Engelbrecht (SA)
  • Rob Fender (UK)
  • Griffin Foster (UK)
  • Paulo Freire (DE)
  • Jason Hessels (NL)
  • Tana Jospeh (SA)
  • Aris Karastergiou (UK)
  • Ramesh Karuppusamy (DE)
  • Evan Keane (UK)
  • Lars Künkel (DE)*
  • Casey Law (US)
  • Joseph Lazio (US)
  • Joeri van Leeuwen (NL)
  • Lina Levin-Preston (UK)
  • Maura McLaughlin (US)
  • Prajwal Voraganti Padmanabh (DE)*
  • Andrea Possenti (IT)
  • Scott Ransom (US)
  • Maciej Serylak (SA)
  • Ingrid Stairs (CA)
  • Gilles Theureau (FR)
  • Christo Venter (SA)
  • Patrick Weltevrede (UK)
  • Christoph Weniger (NL)
  • Norbert Wex (DE)

+ PDRA

* PhD Student

Project Organisation:

The management of the TRAPUM project will build upon experience gained from our membership in other large international collaborations such as LOFAR, the EPTA and SUPERB. An executive committee composed of the two PIs (Stappers and Kramer) and a further five members will be the decision making body responsible for organisation, membership, resolution, funding and planning. These five additional members correspond to approximately 10% of the total membership and will be drawn from each of the science working groups (see below), respecting diversity in nationality and gender, and will serve a limited term of no more than two years. The PIs will have the casting vote if required. While the science working groups will have significant overlap in membership and science topics they will have clear and distinct goals. In addition there will be two technology working groups which will work with and across all the science groups to provide the hardware, software and practical development necessary to meet the scientific goals. It is expected that the technology group members will have strong overlap with all the scientific groups, with at least one member from each present.

The working groups are broken down into the following:

  • Galactic plane survey: Planning and executing the Galactic plane and Fermi excess survey. This is the largest single observing project and will require strong coordination of resources to ensure the most ecient observing. It will liase strongly with the targeted surveys group to ensure no overlap of targets.
  • Targeted surveys: Planning and executing the surveys of the Galactic centre, globular clusters, exter- nal galaxies and high-energy sources. These surveys are grouped together as they all require similar approaches, but they will be broken down further into specific teams which may not include all members.
  • Pulsar follow-up: Extracting maximum information from newly discovered pulsars eciently. Liaise with MeerKAT and worldwide pulsar timing projects for follow up radio timing. Organise observations at high energies, optical and perhaps non-photonic windows.
  • Transient survey and follow-up: Detection of transient signals and triggering of multi-wavelength follow- up observations. Have agreements in place with a variety observatories to follow-up transients at short notice. Liase with ThunderKAT for follow up as well.
  • Commensal observing survey: This task will involve liaising with the different working groups to determine what resources can be used and when and also to optimise the observing strategies of the targeted surveys described above to ensure optimal transient detection capabilities. Overlap with the follow up component of the Transients working group.
  • Beamforming: Development of scheme for phasing up array and polarisation and flux calibration. Includes experts who have performed similar work with other arrays like WSRT,VLA and LOFAR. Majority of the work will be in the initial phases of roll out of beamforming, but then will have a continuing reduced role to assess problems if/when they arise with calibration and related issues.
  • Processing: Particular focus on searching multiple data streams for periodic and transient signals. Also responsible for the organisation of data types, storage and transfer. Includes experts in machine learning approaches to transient and pulsar candidate identification.
  • Outreach working group: This is an important aspect of the proposal which all members will contribute to. It will be led by people with significant experience in professional and public outreach and educators.

Publications

Relevant papers and publications will be posted here when they are released.

Data Access

Data download will be available once the survey has begun, and in line with the data-release policy

Public Engagement

Our public engagement programme focuses on the distinct areas: the public at large, and school children in particular. The school-focused thrust engages children in South Africa and other SKA-node-bearing countries as a first priority, but with a global component as well. The content of the various components listed below relates to the TRAPUM mission, which focuses on radio transients and pulsars. Below are the main components planned in our public engagement programme for TRAPUM:

  • Produce a monthly newsletter to appear in a selection of South African print media, as well as online news portals. Existing contacts with independent science writers in South Africa to be followed up.
  • Perform hands-on, real observing and data analysis, engagements with schools building on the extensive experience of our team members but tailoring it to the specific needs.
  • Engage with the IAU’s OAD office and the SKA Communication and Outreach Team to see if mutually beneficial programmes can be launched as part of the TRAPUM public engagement programme.
  • Establish a TRAPUM citizen science component that will evolve from the Zooniverse project Pulsar Hunters and use it as a mean for public engagement but also to enable science in its own right.
  • Design, set up and maintain a well-structured webpage as well as both Twitter and Facebook profiles.
  • Develop simple pulsar-related materials that can be used in schools in a variety of modalities.
  • TRAPUM members will get involved in speaking at local schools during their visits to South Africa.
  • Involve current SKA bursary holders at universities to participate and contribute to this programme.

Policy Documents

Publication Policy document is currently being drafted.

Membership Policy document is being updated, in the mean time please contact the PIs directly