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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 pulsars 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.
 * Improve our understanding of gravity, by discovering relativistic binaries
   and millisecond pulsars suitable for gravitational wave experiments.
 * Working with MeerTRAP 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 and Search for high red-shift radio bursts and
   use them to refine cosmology.




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 as
granted in 2016. Target Fraction SNRs,PWNe,TeV & γ-ray 44% Globular Clusters 33%
Nearby Galaxies 22%

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.

Towards a Galactic census
The known pulsar population has increased by nearly 50% sources, since 2010 when
TRAPUM was first envisioned. This increase has been achieved by improving
techniques and methods on existing telescopes, and new telescopes like LOFAR.
Still, the task of finding even more pulsars could not be more timely. 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
Galactic plane - the birth place of pulsars - provides a significant and rare
sharp increase in sensitivity for exploring the dynamic radio sky. The hundreds
of 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. With time provided by MPIfR’s “S-Band Project”, TRAPUM
will conduct a L-Band survey along parts of the inner Galaxy. This 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.

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. As part of the MPIfR “S-Band
Project”, the Max-Planck receivers will be used to conduct a sensitive survey of
the innermost region of the Galaxy in the vicinity of the black hole. The MPIfR
will share the results with TRAPUM as input for further studies.

Fast transients – working with MeerTRAP to discovering and understand source
populations
The fast transient landscape has changed dramatically since 2010 with the
discovery of the population of FRBs, including the revelation that some repeat,
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: High energy
point sources and SNRs, globular clusters and external galaxies.


Follow Up Timing
After the initial discovery of a pulsar, we want to extract as much science as
possible 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


GLOBULAR CLUSTER PULSAR POPULATION DOUBLES IN 5 YEARS

Oct 2023

With the most recent discoveries by the MeerKAT and FAST radio telescopes, the
number of pulsars known in globular clusters has grown to 302, up from around
150 at the end of 2018. This doubling of the population in 5 years is a
testament to the immense sensitivity of MeerKAT and FAST, with the TRAPUM
project alone now accounting for 28% of all globular cluster pulsar discoveries!


EINSTEIN@HOME JOINS THE TRAPUM EFFORT TO SEARCH FOR PULSARS

Jan 2023

We have recently initiated a project to search for exotic binary pulsars in
TRAPUM globular cluster data using spare compute cycles of computers from
volunteers all around the world. This is part of the already running
Einstein@Home project, which has been running successfully for nearly two
decades and has discovered more than 80 pulsars. Anyone with a personal computer
can freely sign up as a volunteer following the instructions on the
Einstein@Home website and join our large-scale effort for discovering unique
pulsars.


FIRST NEARBY GALAXIES PUBLICATION AND FIRST LMC OBSERVATIONS!

Oct 2022

The Nearby Galaxies working group has now published its first paper! It can be
found in the "Publications" section of this website. Remarkably, the first two
observations of the Large Magellanic Cloud already revealed 6 new pulsars! The
Small Magellanic Cloud survey is also well under way with 7 pulsar discoveries,
doubling the currently known population. In addition, nearby galaxies Sextans A
and B have been surveyed and a Fast Radio Burst has been found serendipitously.
A survey of NGC 253 is currently being processed. Details of our discoveries can
be found on the DISCOVERIES page.


TRAPUM/MMGPS REACHES 100 DISCOVERIES!

Jan 2022

We are proud to announce that TRAPUM together with its sister project the MPIfR
MeerKAT Galactic Plane Survey (MMGPS) have surpassed 100 pulsar discovieries.
Given the source classes that TRAPUM has targeted, more than 60 of these new
pulsars have periods below 30 milliseconds with 37 confirmed to be in binary
systems. This represents more than a 10% increase in the total number of
millisecond pulsars known. With the majority of the discovieres coming since the
start of 2021 we are optimistic that we can continue our fantastic discovery
rate into 2022 and beyond. Details of our discoveries can be found on the
DISCOVERIES page.


TRAPUM FIRST YEAR REVIEW

Jan 2022

Towards the end of 2021 the TRAPUM collaboration submitted its first report on
operations to SARAO. The report detailed how the addition of instrumentation
from TRAPUM has enabled MeerKAT to become a premium pulsar and fast transient
discovery machine, with TRAPUM discovering 36 pulsars in 11 globulsar clusters,
3 pulsars in the Small Magellanic Cloud and 15 pulsars (of which 14 are
millisecond pulsars) in Fermi-LAT sources. The collaboration received positive
feedback from the review committee with the reviewers noting that "The TRAPUM
team has demonstrated, through their hard work in collaboration with SARAO
teams, that MeerKAT (and by extension SKA1-MID) can be a prolific pulsar search
instrument. This required the development of novel instrumentation, and they are
to be commended for their achievements. Their transparency in making discovery
details public is also welcome. Given their activities and results so far, it
would appear that the team is well poised to make major impacts in pulsar
astrophysics."


FIRST EXTRAGALACTIC PULSAR DISCOVERIES!

2021

We have started our observations of the Small Magellanic Cloud with TRAPUM in
2021. We have nearly completed four out of eight pointings in this L-band
survey, which uses 769 coherent beams and the core dishes of MeerKAT. The survey
is partially targeted to supernova remnants and pulsar wind nebulae. We have
discovered several new extragalactic pulsars in the SMC, which you can read
about on the DISCOVERIES webpage. We are also observing other nearby galaxies
with the full array.


FIRST FERMI UNIDENTIFIED SOURCES SEARCH OBSERVATIONS!

20 June 2020

We have made our first observations of a set of Fermi Unidentified Sources with
TRAPUM. We observed about a dozen sources using all the available telescopes and
about 250 beams arranged to sample the entire gamma-ray error circle of the
sources. This forms the first set of sources in our sample prepared for our
initial shallow survey which is using the L-band receiver and will include a
two-pass approach. News on DISCOVERIES soon.


FIRST GLOBULAR CLUSTER OBSERVATIONS!

April & May 2020

TRAPUM has made its first observations! Using all the available telescopes 288
beams were formed and used to observe the clusters Terzan 5, 47 Tucanae and NGC
6624 for about 4 hours each. Data analysis is ongoing. Stand by for
announcements of discoveries which will appear on our DISCOVERIES webpage.


GLOBULAR CLUSTER PULSARS DISCOVERED

Update May 2020

Working with the MeerTIME team we have searched 10 Globular clusters using
search mode data recorded using the PTUSE backends for a beam pointed at one of
the known pulsars in the cluster. So far we have discovered 10 new pulsars and
you can find a summary of the details of these pulsars at our DISCOVERIES
webpage. The TRAPUM surveys will use between 250 and 400 beams to allow for
covering the entire cluster and will be able to use all 64 dishes to give
greater sensitivity.


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)


WORKING GROUP CHAIRS

 * Lina Levin-Preston (UK, Nearby Galaxies)
 * Ben Stappers (UK, PWNe/SNR/TeV WG)
 * Rene Breton (UK, Fermi WG Co-chair)
 * Colin Clark (DE, Fermi WG Co-chair)
 * Alessandro Ridolfi (IT, Globular Clusters WG)
 * Marta Burgay (IT, Follow-up WG)


CO-IS

 * Federico Abbate (IT)
 * Anjana Ashok (DE)*
 * Matthew Bailes (AU)
 * Vishnu Balakrishnan (DE)
 * Werner Becker (DE)
 * Miquel Colom I Bernadich (DE)*
 * Joanna Berteaud (FR)
 * Mechiel Bezuidenhout (UK)*
 * Markus Böttcher (SA)
 * Sarah Buchner (SA)
 * Francesca Calore (NL)
 * Emma Carli (UK)*
 * David Champion (DE)
 * Weiwei Chen (DE)
 * Ismaël Cognard (FR)
 * Sergio Belmonte Diaz (UK)*
 * Oliver Dodge (UK)*
 * Andrew Douglas (USA)*

 * Liam Dunn (AUS)*
 * Arunima Dutta (DE)*
 * Ralph Eatough (CH)
 * Elisabeth Ferrara (USA)
 * Paulo Freire (DE)
 * Tasha Gautam (DE)*
 * Lucía Gebauer Werner(DE)*
 * Marisa Geyer (SA)
 * Marisa Geyer (SA)
 * Heinrich Hurter (SA)*
 * Jean-Mathias Griessmeier (FR)
 * Jedrzej Jawor (DE)*
 * Tana Joseph (NL)
 * Ramesh Karuppusamy (DE)
 * Evan Keane (IRL)
 * Lars Künkel (DE)*
 * Yunpeng Men (DE)
 * Vanessa McBride (SA)
 * Rouhin Nag (IT)*
 * Lars Nieder (DE)
 * Prajwal Voraganti Padmanabh (DE)
 * Adipol Phosrisom (UK)*
 * Viviana Piga (IT)*

 * Denisha Pillay (DE)*
 * Andrea Possenti (IT)
 * Venu Prayag (SA)*
 * Harry Qui (UK)
 * Isabella Rammala (DE)
 * Shilpa Ranchod (DE)*
 * Scott Ransom (US)
 * Shalini Sengupta (DE)*
 * Maciej Serylak (UK)
 * Tinn Thongmeearkom (UK)*
 * Naomi Titus (SA)
 * James Turner (UK)*
 * Vivek Venkatraman Krishnan (DE)
 * Christo Venter(SA)
 * Laila Vleeschower Calas (UK)*
 * Stefan Wagner (DE)
 * Patrick Weltevrede (UK)
 * Christoph Weniger (NL)
 * Norbert Wex (DE)

* Student


PROJECT ORGANISATION:

The management of the TRAPUM project is built 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 forms the decision making body responsible for
organisation, membership, resolution, funding and planning. The five additional
members correspond to approximately 10% of the total membership and are drawn
from each of the science working groups (see below), respecting diversity in
nationality and gender, and serve a limited term of no more than two years. The
PIs have the casting vote if required. While the science working groups have
significant overlap in membership and science topics they also have clear and
distinct goals. In addition there is a technology working group that works with
and across all the science groups to provide the hardware, software and
practical development necessary to meet the scientific goals.


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



1) WIDE FIELD BEAMFORMED OBSERVATION WITH MEERKAT

(Chen et al. 2021): ADS, ArXiv, DOI

We describe a wide-field beamformer for the MeerKAT radio telescope and outline
strategies to optimally design pulsar and fast transient surveys.



2) EIGHT NEW MILLISECOND PULSARS FROM THE FIRST MEERKAT GLOBULAR CLUSTER CENSUS

(Ridolfi et al. 2021): ADS, ArXiv, DOI

We present the first eight pulsar discoveries made by MeerKAT. The eight pulsars
are found in six different globular clusters and are all millisecond pulsars.

Pulsars: J1748-2446an, J1701-3006G, J1803-3002D, J1823-3021G, J0024-7204ac,
J0024-7204ad, J1910-5959F, J1823-3021H



3) TWO NEW BLACK WIDOW MILLISECOND PULSARS IN M28

(Douglas et al. 2022): ADS, ArXiv, DOI

We report the discovery of two Black Widow millisecond pulsars in the globular
cluster M28 with the MeerKAT telescope.

Pulsars: J1824−2452M, J1824−2452N



4) TRAPUM DISCOVERY OF 13 NEW PULSARS IN NGC 1851 USING MEERKAT

(Ridolfi et al. 2022): ADS, ArXiv, DOI

We report the discovery of 13 new pulsars in the globular cluster NGC 1851 with
the MeerKAT telescope.

Pulsars: J0514-4002B, J0514-4002C, J0514-4002D, J0514-4002E, J0514-4002F,
J0514-4002G, J0514-4002H, J0514-4002I, J0514-4002J, J0514-4002K, J0514-4002L,
J0514-4002M, J0514-4002N



5) DISCOVERIES AND TIMING OF PULSARS IN NGC 6440

(Vleeschower et al. 2022): ADS, ArXiv, DOI

We report the MeerKAT discovery of two pulsars in the globular cluster NGC 6440,
as well as long-term timing solutions of the previously known pulsars NGC 6440C
and NGC 6440D from multi-telescope data.

Pulsars: J1748−2021G, J1748−2021H



6) FOUR PULSAR DISCOVERIES IN NGC 6624 BY TRAPUM USING MEERKAT

(Abbate et al. 2022): ADS, ArXiv, DOI

We report the discovery of four new pulsars in the globular cluster NGC 6624
with the MeerKAT telescope. One of these (J1823-3022) shows a large offset in
its position and dispersion measure when compared to all the other pulsars in
NGC 6624, making its association with the cluster uncertain.

Pulsars: J1823-3021I, J1823-3021J, J1823-3021K, J1823-3022



7) RADIO DETECTION OF AN ELUSIVE MILLISECOND PULSAR IN THE GLOBULAR CLUSTER NGC
6397

(Zhang et al. 2022): ADS, ArXiv, DOI

We report the discovery of a new pulsars (PSR J1740-5340B) in the globular
cluster NGC 6397. The pulsar was found with the Parkes radio telecope and
confirmed with the MeerKAT telescope in two TRAPUM observations. PSR J1740-5340B
is an eclipsing redback in a 1.97-day orbit, the longest among all redbacks
known.

Pulsars: PSR J1740-5340B



8) TRAPUM UPPER LIMITS ON PULSED RADIO EMISSION FOR SMC X-RAY PULSAR J0058−7218

(Carli et al. 2022): ADS, ArXiv, DOI

As part of our survey of the Small Magellanic Cloud, we have published an upper
limit on radio pulsations from X-ray pulsar J0058−7218. This limit is 7 times
deeper than previous radio searches. This suggests that the radio emission of
PSR J0058−7218 is not beamed towards Earth or that PSR J0058−7218 is similar to
a handful of Pulsar Wind Nebulae systems that have a very low radio efficiency,
such as PSR B0540−6919, the Large Magellanic Cloud Crab pulsar analogue.

Pulsar: PSR J0058-7218



9) THE TRAPUM L-BAND SURVEY FOR PULSARS IN FERMI-LAT GAMMA-RAY SOURCES

(Clark et al. 2023): ADS, ArXiv, DOI

We present the discovery of 9 new millisecond pulsars, the first results from
our targeted survey of unidentified Fermi-LAT gamma-ray sources. All but one of
these new pulsars are in binary systems, of which two are eclipsing redbacks
with optical counterparts.

Pulsars: J1036-4353, J1526-2744, J1623-6936, J1709-0333, J1757-6032, J1803-6707,
J1823-3543, J1858-5422, J1906-1754



10) MISSING FOR 20 YR: MEERKAT REDETECTS THE ELUSIVE BINARY PULSAR M30B

(Balakrishnan et al. 2023): ADS, ArXiv, DOI

We report the re-discovery of PSR J2140−2311B located in the globular cluster
M30 and detected using the MeerKAT telescope. This pulsar has eluded detections
for the past 20 years and its orbital parameters have been a mystery until now.
PSR J2140−2311B has an orbital period of 6.2 days and is in a highly eccentric
orbit (e = 0.879) around either a WD/NS. We also measured wdot from pulsar
timing and assuming GR, we present here the total mass of the system. This
pulsar is located 1.2(1)' from the cluster center and likely formed as a result
of a secondary exchange encounter.

Pulsars: PSR J2140−2311B



11) THE MPIFR–MEERKAT GALACTIC PLANE SURVEY – I. SYSTEM SET-UP AND EARLY RESULTS

(Padmanabh et al. 2023): ADS, ArXiv, DOI

We present here the overview and setup for the 3000 hour Max-Planck-Institut
fuer Radioastronomie (MPIfR) MeerKAT Galactic Plane survey (MMGPS). The survey
is unique by operating in a commensal mode, addressing key science objectives of
the survey including the discovery of new pulsars and transients as well as
studies of Galactic magnetism, the interstellar medium and star formation rates.
We have so far discovered 78 new pulsars including 17 confirmed binary systems
of which two are potential double neutron star systems. We have also developed
an imaging pipeline sensitive to the order of a few tens of micro-Jansky with a
spatial resolution of a few arcseconds. Further science operations with an
in-house built S-Band receiver operating between 1.7-3.5 GHz are about to
commence.

Pulsars: J0853−4648, J0916−5243, J0917−4413, J0922−4534, J0927−5242, J0933−4604,
J0936−4750, J0948−5549, J0954−5754, J1001−5603, J1015−5359, J1020−5510,
J1020−6158, J1030−6008, J1034−5817, J1034−5934, J1039−6108, J1039−6208,
J1051−6214, J1108−6329, J1134−6207, J1138−6154, J1148−6546, J1155−6529,
J1208−5936, J1212−5838, J1231−5929, J1232−5843, J1244−6437, J1306−6043,
J1316−6147, J1328−6605, J1338−6425, J1352−6141, J1353−6341, J1359−6242,
J1408−6009, J1409−6011, J1413−5936, J1426−6136, J1436−6405, J1449−6339,
J1452−5549, J1454−5416, J1500−6054, J1510−5254, J1512−6029, J1520−5402,
J1526−5652, J1529−5102, J1529−5609, J1530−5724, J1536−6142, J1536−6149,
J1540−5821, J1543−5439, J1547−5056, J1554−4854, J1554−5906, J1604−4832,
J1610−4938, J1614−4608, J1615−5609, J1623−4608, J1623−4931, J1633−4859,
J1636−4217, J1645−4836, J1649−3752, J1649−4230, J1650−5025, J1652−5154,
J1702−4145, J1704−3549, J1706−4020, J1708−4843, J1716−3811, J1806−2125



12) THE MPIFR-MEERKAT GALACTIC PLANE SURVEY - II. THE ECCENTRIC DOUBLE NEUTRON
STAR SYSTEM PSR J1208−5936 AND A NEUTRON STAR MERGER RATE UPDATE

(Bernadich et al. 2023): ADS, ArXiv, DOI

We present follow-up study of PSR J1208-5936, a 28.71-ms recycled pulsar in a
double neutron star system with an orbital period of 0.632 days and an orbital
eccentricity of 0.348, merging within the Hubble time. From one year of timing
we detected the relativistic advance of periastron of 0.918(1) deg/yr, resulting
in a total system mass of 2.586(5) solar masses. Using the sensitivity of the
MMGPS-L survey and the fact of PSR J1208-5936 discovery, we provide updated
estimates of the neutron star merger rate.

Pulsars: J1208-5936



13) MEERKAT DISCOVERY OF 13 NEW PULSARS IN OMEGA CENTAURI

(Chen et al. 2023): ADS, ArXiv, DOI

We report the discovery of 13 new pulsars in globular cluster Omega Centauri.
With this discovery and the known pulsars, we discuss the ratio between isolated
and binaries pulsars and how they were formed in this cluster.

Pulsars: J1326-4728F, J1326-4728G, J1326-4728H, J1326-4728I, J1326-4728J,
J1326-4728K, J1326-4728L, J1326-4728M, J1326-4728N, J1326-4728O, J1326-4728P,
J1326-4728Q, J1326-4728R



14) PULSARX: A NEW PULSAR SEARCHING PACKAGE -I. A HIGH PERFORMANCE FOLDING
PROGRAM FOR PULSAR SURVEYS

(Men et al. 2023): ADS, ArXiv, DOI

We describe a novel, efficient approach to candidate folding for large-scale
pulsar surveys. The approach is implemented in the PulsarX software package and
is tested on the MMGPS and TRAPUM surveys where we show that the cost of
dedipsersion can be reduced by upto a factor of 50 when compared to traditional
approaches.



15) NEUTRON STAR MASS ESTIMATES FROM GAMMA-RAY ECLIPSES IN SPIDER MILLISECOND
PULSAR BINARIES

(Clark et al. 2023): ADS, ArXiv, DOI

We present the detection of eclipses in the gamma-ray pulsations from 7 binary
millisecond pulsars. These eclipses allow us to better constrain the masses of
the pulsars in these systems, by providing us with information on the angles
from which we view these binaries. TRAPUM observations contributed to the timing
solution for one of the pulsars included in this search.

Pulsars: J0838−2827, J0955−3949, J2333−5526



16) MEERKAT CAUGHT A MINI MOUSE: SERENDIPITOUS DETECTION OF A YOUNG RADIO PULSAR
ESCAPING ITS BIRTH SITE

(Motta et al. 2023): ADS, ArXiv, DOI

We report on the serendipitous discovery of a radio nebula with cometary-like
morphology. The feature, which we named ‘the Mini Mouse’ based on its similarity
to the previously discovered ‘Mouse’ nebula, was observed with MeerKAT and we
localisted the known young pulsar J1914+1054g to the head of the nebula.

Pulsars: J1914+1054g



17) A MEERKAT VIEW OF THE PULSARS IN THE GLOBULAR CLUSTER NGC 6522

(Abbate et al. 2023): ArXiv, DOI

We present the discovery of two isolated pulsars in the globular cluster NGC
6522. The discoveries confirm predictions of previous theories for the pulsar
populations in late-stage core-collapsed globular clusters.

Pulsars: J1803−3002E, J1803−3002F, J1803−3002C



18) A PULSAR IN A BINARY WITH A COMPACT OBJECT IN THE MASS GAP BETWEEN NEUTRON
STARS AND BLACK HOLES

(Barr, Dutta et al. 2024): ADS, ArXiv, DOI

We present the results of pulsar timing observations of the binary system
J0514‑4002E in the globular cluster NGC 1851. Analysis of these observations
shows that J0514‑4002E is in orbit around a massive compact companion whose mass
lies in the gap between the heaviest neutron stars and the lightest black holes.
This may be the first identified pulsar in orbit around a stellar mass black
hole.

Pulsars: J0514‑4002E



19) THE TRAPUM SMALL MAGELLANIC CLOUD PULSAR SURVEY WITH MEERKAT - I. DISCOVERY
OF SEVEN NEW PULSARS AND TWO PULSAR WIND NEBULA ASSOCIATIONS

(Carli et al. 2024a): ADS, ArXiv, DOI

We report the discovery of seven new SMC pulsars, doubling this galaxy’s radio
pulsar population and increasing the total extragalactic population by nearly a
quarter. Our discoveries reveal the first two radio pulsar-PWN systems in the
SMC, with only one such system previously known outside our galaxy.

Pulsars: J0040−7326, J0040−7335, J0040−7337, J0043−73, J0044−7314, J0048−7317,
J0052−72, J0054−7228, J0105−7208



20) THE TRAPUM SMALL MAGELLANIC CLOUD PULSAR SURVEY WITH MEERKAT - II. NINE NEW
RADIO TIMING SOLUTIONS AND GLITCHES FROM YOUNG PULSARS

(Carli et al. 2024b): ADS, ArXiv, DOI

We report new radio timing solutions from a three-year observing campaign
conducted with the MeerKAT and Murriyang telescopes for nine Small Magellanic
Cloud pulsars, increasing the number of characterised rotation-powered
extragalactic pulsars by 40 per cent. We find that our two new Pulsar Wind
Nebula pulsars are giant glitchers and may be Vela-like.

Pulsars: J0040−7326, J0040−7335, J0040−7337, J0043−73, J0044−7314, J0048−7317,
J0052−72, J0054−7228, J0105−7208



21) TRAPUM PULSAR AND TRANSIENT SEARCH IN THE SEXTANS A AND B GALAXIES AND
DISCOVERY OF BACKGROUND FRB 20210924D

(Carli et al. 2024c): ADS, ArXiv, DOI

Motivated by the sensitivity of the MeerKAT telescope, we searched the dwarf
star-forming galaxies Sextans A and B, situated at the edge of the local group
1.4 Mpc away and found a background Fast Radio Burst.



22) TRANSIENTX: A HIGH PERFORMANCE SINGLE PULSE SEARCH PACKAGE

(Men & Barr, 2024): ArXiv, DOI

We report on the development of a high-performance single-pulse search software:
TransientX. This package combines radio frequency interference mitigation,
dedispersion, matched filtering, cluster and candidate plotting. In TransientX,
we have developed an efficient CPU-based de-dispersion implementation using the
sub-band de-dispersion algorithm. Additionally, TransientX employs the
density-based spatial clustering of applications with noise (DBSCAN) algorithm
to eliminate duplicate candidates, utilizing an efficient implementation based
on the kd-tree data structure. TransientX offers the capability for efficient
CPU-only real-time single pulse searching.



23) DISCOVERIES AND TIMING OF PULSARS IN M62

(Vleeschower et al. 2024): ArXiv, DOI

We report the discovery of three new pulsars in the globular cluster M62,
bringing the total number of pulsars in the cluster to 10. PSR J1701–3006H is
particularly interesting as it is in a binary system with an extremely light
companion, with a median mass of three times the mass of Jupiter. We also
present 23-yr-long timing solutions obtained using data from the Parkes
'Murriyang', Effelsberg, and MeerKAT telescopes for six previously known
pulsars.

Pulsars: J1701–3006H, J1701–3006I, J1701–3006J



24) DISCOVERY AND TIMING OF TEN NEW MILLISECOND PULSARS IN THE GLOBULAR CLUSTER
TERZAN 5

(Padmanabh et al. 2024): ArXiv, DOI

We report the discovery of ten new pulsars in the globular cluster Terzan 5,
bringing the total number of pulsars in the cluster to 49. Highlights include
PSR J1748-2446ao, which is a candidate double neutron star system with a total
mass of 3.17 solar masses, and PSR J1748-2446ap, which has the second highest
eccentricity for any recycled pulsar (e=0.905).

Pulsars: J1748-2446ao, J1748-2446ap, J1748-2446aq, J1748-2446ar, J1748-2446as,
J1748-2446at, J1748-2446au, J1748-2446av, J1748-2446aw, J1748-2446ax



25) TRAPUM SEARCH FOR PULSARS IN SUPERNOVA REMNANTS AND PULSAR WIND NEBULAE − I.
SURVEY DESCRIPTION AND INITIAL DISCOVERIES

(Turner et al. 2024): ArXiv, DOI

We present the description and initial results of the TRAPUM (TRAnsients And
PUlsars with MeerKAT) search for pulsars associated with supernova remnants
(SNRs), pulsar wind nebulae and unidentified TeV emission.

Pulsars: J1831-0941, J1818-1502



26) MASS ESTIMATES FROM OPTICAL MODELLING OF THE NEW TRAPUM REDBACK PSR
J1910-5320

(Dodge et al. 2024): ArXiv, DOI

We present the discovery of a new redback millisecond pulsar binary system, and
modelling of optical spectroscopy and photometry that provides estimates for the
masses of the pulsar and companion star.

Pulsar: J1910-5320



27) A TARGETED RADIO PULSAR SURVEY OF REDBACK CANDIDATES WITH MEERKAT

(Thongmeearkom et al. 2024): ArXiv, DOI

Redbacks are millisecond pulsar binaries with low mass, irradiated companions.
These systems have a rich phenomenology that can be used to probe binary
evolution models, pulsar wind physics, and the neutron star mass distribution. A
number of high-confidence redback candidates have been identified through
searches for variable optical and X-ray sources within the localisation regions
of unidentified but pulsar-like Fermi-LAT gamma-ray sources. However, these
candidates remain unconfirmed until pulsations are detected. As part of the
TRAPUM project, we searched for radio pulsations from six of these redback
candidates with MeerKAT. We discovered three new radio millisecond pulsars, PSRs
J0838−2527, J0955−3947 and J2333−5526, confirming their redback nature. PSR
J0838−2827 remained undetected for two years after our discovery despite
repeated observations, likely due to evaporated material absorbing the radio
emission for long periods of time. While, to our knowledge, this system has not
undergone a transition to an accreting state, the disappearance, likely caused
by extreme eclipses, illustrates the transient nature of spider pulsars and the
heavy selection bias in uncovering their radio population. Radio timing enabled
the detection of gamma-ray pulsations from all three pulsars, from which we
obtained 15-year timing solutions. All of these sources exhibit complex orbital
period variations consistent with gravitational quadrupole moment variations in
the companion stars. These timing solutions also constrain the binary mass
ratios, allowing us to narrow down the pulsar masses. We find that PSR
J2333−5526 may have a neutron star mass in excess of 2 M⊙.

Pulsars: J0838−2827, J0955-3947, J2333-5526



28) THE TRAPUM LARGE MAGELLANIC CLOUD PULSAR SURVEY WITH MEERKAT I: SURVEY SETUP
AND FIRST 7 PULSAR DISCOVERIES

(Prayag et al. 2024): ArXiv, DOI

The Large Magellanic Cloud (LMC) presents a unique environment for pulsar
population studies due to its distinct star formation characteristics and
proximity to the Milky Way. We are using the core array of the MeerKAT radio
telescope (MeerKAT) to conduct a targeted search of the LMC for radio pulsars at
L-band frequencies, 856–1712 MHz. The excellent sensitivity of MeerKAT, coupled
with a 2-hour integration time, makes the survey 3 times more sensitive than
previous LMC radio pulsar surveys. We report the results from the initial four
survey pointings which has resulted in the discovery of seven new radio pulsars,
increasing the LMC radio pulsar population by 30 per cent. The pulse periods of
these new pulsars range from 278 to 1690ms, and the highest dispersion measure
is 254.20 pc/cm^–3. We searched for, but did not find any significant pulsed
radio emission in a beam centred on the SN1987A remnant, establishing an upper
limit of 6.3 μJy on its minimum flux density at 1400 MHz.

Pulsars: J0509–6838, J0509–6845, J0518–6939, J0518–6946, J0519–6931, J0534–6905



29) SEARCHING FOR PULSARS, MAGNETARS, AND FAST RADIO BURSTS IN THE SCULPTOR
GALAXY USING MEERKAT

(Hurter et al. 2024): ArXiv, DOI

The Sculptor Galaxy (NGC 253), located in the Southern Hemisphere, far off the
Galactic Plane, has a relatively high star-formation rate of about 7 M⊙ yr-1 and
hosts a young and bright stellar population, including several super star
clusters and supernova remnants. It is also the first galaxy, apart from the
Milky Way Galaxy to be associated with two giant magnetar flares. As such, it is
a potential host of pulsars and/or fast radio bursts in the nearby Universe. The
instantaneous sensitivity and multibeam sky coverage offered by MeerKAT
therefore make it a favourable target. We searched for pulsars, radio-emitting
magnetars, and fast radio bursts in NGC 253 as part of the TRAPUM large survey
project with MeerKAT. We did not find any pulsars during a 4 h observation, and
derive a flux density limit of 4.4 µJy at 1400 MHz, limiting the
pseudo-luminosity of the brightest putative pulsar in this galaxy to 54 Jy
kpc^2. Assuming universality of pulsar populations between galaxies, we estimate
that detecting a pulsar as bright as this limit requires NGC 253 to contain a
pulsar population of ⪞20 000. We also did not detect any single pulses, and our
single pulse search flux density limit is 62 mJy at 1284 MHz. Our search is
sensitive enough to have detected any fast radio bursts and radio emission
similar to the brighter pulses seen from the magnetar SGR J1935+2154 if they had
occurred during our observation.



30) RADIO AND GAMMA-RAY TIMING OF TRAPUM L-BAND FERMI PULSAR SURVEY DISCOVERIES

(Burgay et al. 2024): (Accepted in A&A, links to follow....)

This paper presents the results of a joint radio and gamma-ray timing campaign
on the nine millisecond pulsars (MSPs) discovered as part of the L-band targeted
survey of Fermi-LAT sources performed by TRAPUM. Out of these pulsars, eight are
members of binary systems; of these eight, two exhibit extended eclipses of the
radio emission. Using an initial radio timing solution, pulsations were found in
the gamma rays for six of the targets. For these sources, a joint timing
analysis of radio times of arrival and gamma-ray photons was performed, using a
newly developed code that optimises the parameters through a Markov chain Monte
Carlo (MCMC) technique. This approach has allowed us to precisely measure both
the short- and long-term timing parameters. This study includes a proper motion
measurement for four pulsars, which a gamma ray-only analysis would not have
been sensitive to, despite the 15-year span of Fermi data.

Pulsars: J1036−4353, J1526−2744, J1623−6936, J1709−0333, J1757−6032, J1803−6707,
J1823−3544, J1858−5422, J1906−1754


PUBLIC ENGAGEMENT

Our public engagement program is focused on two primary areas: reaching the
general public and engaging with school children, particularly in South Africa
and other countries associated with the SKA project.

Below are the main components of our public engagement program for TRAPUM:

 * Produce a monthly newsletter featured in select South African print media and
   online news portals. We are also fostering relationships with independent
   science writers.
 * Conduct hands-on observing and data analysis sessions with schools, tailored
   to their specific needs.
 * Collaborate with the IAU’s OAD office and the SKA Communication and Outreach
   Team to develop mutually beneficial programs.
 * Establish a TRAPUM citizen science initiative based on the Zooniverse project
   Pulsar Hunters, promoting public engagement and enabling scientific
   contributions.
 * Maintain a well-structured webpage, along with X (Twitter) and LinkedIn
   profiles.
 * Develop pulsar-related educational materials suitable for various school
   environments.
 * Develop different formats to inform the general public about TRAPUM topics
   (e.g. poster, video series “Meet the team”).
 * Deliver presentations at local schools by TRAPUM members during visits to
   South Africa.
 * Engage current SKA bursary holders at universities to participate in and
   contribute to the program.

Introduce young astronomers to the fascinating science behind the TRAPUM project
and the power of the MeerKAT radio telescope with this kid-friendly booklet.

Stay up-to-date with the latest TRAPUM news on social media:


DATA RELEASES

TRAPUM data are generally large with only specific data sets being retained for
future use (e.g. candidate sets and beams of particular scientific interest,
such as those on the cores of globular clusters). We are working with SARAO to
provide open access to some of these data and will update here when download
links are available. In the meantime available TRAPUM data may be released upon
reasonable request.