|
|
|||
Selected highlights from my publications |
press releases / notes |
||
|
|
|||
| 2024/01: | Lightest black hole or heaviest neutron star?
MeerKAT uncovers a mysterious object at the boundary between black holes and neutron stars. (Science paper) |
2024/01: |
Max Planck Institute for Radio Astronomy
press release
Max Planck Society press release See video on the formation of the system. |
|
|
|||
| 2023/01: | Nine new and exotic creatures for the pulsar zoo! (MNRAS paper) |
2023/01: |
Max Planck Institute for Radio Astronomy
press release
Albert Einstein Institute press release |
|
|
|||
| 2023/01: | MeerKAT has just solved the 20-year old mystery of M30B! And it is about to become even more sensitive! (ApJ Letters paper) |
2023/01: | Max Planck Institute for Radio Astronomy press release |
|
|
|||
| 2023/01: | Thirteen new pulsars in ω Centauri found with MeerKAT! (MNRAS paper) |
Note: The globular cluster ω Centauri now has 18 millisecond pulsars. The MeerKAT searches for pulsars in Globular clusters have already found 66 new pulsars! | |
| 2022/03: | Thirteen new pulsars in NGC 1851 found with MeerKAT! (A&A paper) |
Note: This globular cluster had one known pulsar (NGC 1851A), now it has fourteen. Two of the new systems are like NGC 1851A: they have massive companions and are in eccentric orbits. They are clearly the result of exchange interations. One of them, NGC 1851E, seems to be unusually massive! (see update on 2024 01). | |
|
|
|||
| 2021/10: | Einstein wins again: The theory of general relativity passes a range of precise tests set by pair of extreme stars. (Phys. Rev. X. paper) |
2021/12: |
Max Planck Institute for Radio Astronomy
press release
Max Planck Society press release |
|
|
|||
| 2021/10: | Breaking new ground with PSR J2222−0137!
(A&A paper) |
Note: Our timing of this massive pulsar has ruled out spontaneous scalarisation in the Scalar-tensor theories of gravity. | |
|
|
|||
| 2021/03: | MeerKAT starts testing Einstein's theory and studying Nature's most compact objects! (MNRAS paper) |
2021/05: | Max Planck Institute for Radio Astronomy press release |
| 2021/03: | First new pulsars from MeerKAT! (MNRAS paper) |
2021/04: |
Max Planck Institute for Radio Astronomy
press release
Max Planck Society press release |
|
|
|||
| 2021/03: | I got JWST time! |
2021/03: | Abstract of proposal |
|
|
|||
| 2020/12: | Arecibo telescope collapses. |
2020/12: | US National Science Foundation
news releases.
See a Scientific American story on this sad event. |
|
|
|||
| 2020/10: | Most compact binary pulsar ever! (ApJ Letters paper) |
2020/10: |
Albert Einstein Institute press release
University of Manchester press release |
|
|
|||
| 2020/07: | A new population of merging, asymmetric double neutron stars! (Nature paper) |
2020/07: |
University of East Anglia press release
University of Central Florida press release |
|
|
|||
| 2020/05: | The most stringent test of the strong equivalence principle with the pulsar in a triple star system! (Astronomy & Astrophysics paper) |
2020/06: |
Max Planck Institute for Radio Astronomy press release
Max Planck Society press release |
|
|
|||
| 2020/01: | A fast rotating white dwarf induces measurable frame dragging in pulsar's orbit! (Science paper) |
2020/01: |
Max Planck Institute for Radio Astronomy press release
Ozgrav press release |
|
|
|||
| 2019/09: | A possible millisecond pulsar - neutron star binary! (MNRAS paper) |
Note: This MSP, which has a very eccentric orbit and a massive companion, is a member of an exotic type of binary pulsar formed by exchange encounters in globular clusters. In this paper, we measure the Einstein delay for this system; this extended by a factor of 40 the range of orbital periods for which this effect has been measured. This allowed a measurement of the mass of the MSP and its companion. An important result of the paper is a detailed discussion of the correlation between the Einstein delay and the change of the projected semi-major axis, something that has already yielded important results. | |
| 2018/09: | An eccentric millisecond pulsar with extreme timing precision! (ApJ paper) |
Note: This is a member of a rare and enigmatic class of eccentric MSPs. This particular pulsar has extremely good timing precision. This and the optical detection of the companion WD make this the first binary pulsar ever where full 3-D position, velocity, orbital orientation and masses are known. This system will be a laboratory for the study of WDs and stellar evolution in general. | |
|
|
|||
| 2018/02: | A new method for phase connection of pulsars! (MNRAS paper / software) |
Note: Until now, getting phase connection for a pulsar was an art, based more or less or recognizing patterns in the residuals and then trying to guess the rotation numbers. Now phase connection is a science. | |
|
|
|||
| 2018/01: | The tightest pulsar - neutron star system known! (ApJ Letters paper) |
2018/01: | See story on NOVA. |
|
|
|||
| 2017/09: | The most accelerated binary pulsar: 70 g! (MNRAS Letters paper) |
2017/09: | Max Planck Institute for Radio Astronomy press release |
|
|
|||
| 2017/11: | Discovered: lightest pulsar - neutron star system known (ApJ paper) |
2018/01: | See story on NOVA |
|
|
|||
| 2017/06: | How double neutron star systems are born.
(ApJ paper) |
Note: This paper will be the bible on formation of double neutron star systems for many years. | |
|
|
|||
| 2017/06: | Proper motions, accelerations and jerks for the pulsars in 47 Tucanae.
(MNRAS paper) |
Note: Lots of nice results from 27 years of timing of the pulsars in 47 Tuc! But no clear evidence of an intermediate mass black hole in the center of the cluster. | |
| 2016/07: | Four elusive binary pulsars in 47 Tucanae finally unveiled!
(MNRAS paper) |
2016/07: | Harvard-Smithsonian Center for Astrophysics science news |
|
|
|||
| 2016/11: | A Massive Millisecond Pulsar in an Eccentric Binary
(MNRAS paper) |
Note: This paper presents one of the most precise mass measurements ever for a millisecond pulsar, 1.828(22) M☉; for PSR J1946+3417, a member of an eccentric MSP - He WD system. This high mass rules out some of the proposed hypotheses for the formation of this mysterious class of binary pulsars. | |
|
|
|||
| 2016/08: | Einstein@@Home discovery of a Double-Neutron Star Binary in the PALFA Survey
(ApJ paper) |
2016/12: |
Max Planck Institute for Radio Astronomy press release Albert Einstein Institute press release Max Planck Society press release See story in Nova |
|
|
|||
| 2016/04: | A millisecond pulsar in an extremely wide binary system!
(MNRAS paper) |
Note: In this paper, we discover that the millisecond pulsar PSR J1024−0719 is orbiting a main sequence star with an orbital period of several thousand years! | |
|
|
|||
| 2016/03: | A Repeating Fast Radio Burst!
(Nature Paper) |
2016/03: |
Max Planck Institute for Radio Astronomy press release
ASTRON press release |
|
|
|||
| 2015/09: | A new double neutron star system with a large mass asymmetry!
(ApJ Paper) |
Note: This paper presents new mass measurements for two neutron stars in a recently discovered double neutron star system, PSR J0453+1559. The masses are: 1.559(5) M☉ for the pulsar and 1.174(4) M☉ for the presumed NS companion. The companion is the lightest NS known. The pulsar is the most massive NS known in a double neutron star system. This system shows that neutron stars can be born with a wider range of masses than previously known. | |
|
|
|||
| 2014/08: | Fast Radio Bursts observed at Arecibo!
(ApJ paper) | 2014/08: |
Max Planck Institute for Radio Astronomy press release For a good story on fast radio bursts, see this article on National Geographic Phenomena. |
|
|
|||
| 2014/02: | Direct formation of millisecond pulsars from rotationally delayed
accretion-induced collapse of massive white dwarfs
(MNRAS Letters paper) |
2013/12: |
Max Planck Institute for Radio Astronomy press release
See Sky and Telescope story on this. |
|
|
|||
| 2014/01: | On the disruption of pulsar and X-ray binaries in globular clusters
(A&A paper) |
Note: This paper presents a new characteristic dynamical parameter of globular clusters, the encounter rate per binary. This parameter goes a long way towards explaining the differences in the characteristics of the pulsar populations of different globular clusters. It also suggests that young pulsars in globular clusters are the results of the disruption of accreting X-ray binaries. | |
|
|
|||
| 2013/09: | Swings between rotation and accretion power in a binary millisecond pulsar
(Nature Paper) |
2013/09: |
ESA press release
NASA press release |
|
|
|||
| 2013/09: | A radio magnetar orbiting the supermassive black hole at the centre of the Galaxy
(Nature Paper) |
2013/08: |
Max Planck Institute for Radio Astronomy press release
Max Planck Society press release |
|
|
|||
| 2013/04: | A super-massive neutron star in a relativistic orbit!
Testing general relativity in a whole new territory! (Science Paper) |
2013/04: |
Max Planck Institute for Radio Astronomy press release
Max Planck Society press release Bonn University press release European Southern Observatory press release Arecibo Observatory press release National Radio Astronomy Observatory press release European Research Council press release |
|
|
|||
| 2012/09: | A new, ever-improving test of general relativity
(Classical and Quantum Gravity paper) |
Note: Invited review in Classical and Quantum Gravity's Focus Issue on the Weak Equivalence Principle. It describes a new, superior method for testing the strong equivalence principle with binary pulsars. | |
|
|
|||
| 2012/07: | The measurement of the mass of PSR J1738+0333 and its companion
allows the most stringent test of scalar-tensor theories of gravity
(MNRAS papers A and B). |
Note: Sequence of two papers published back to back. These introduce very
stringent constraints on scalar-tensor theories of gravity and show how we might
soon exclude a wide family of tensor-vector-scalar theories of gravity that have
been proposed as relativistic formulations of modified Newtonian dynamics.
See Sky and Telescope story on this and other GR tests. |
|
|
|
|||
| 2011/11: | First γ-ray pulsar in a globular cluster
(Science Paper) |
2011/11: | Max Planck Institute for Radio Astronomy press release
Max Planck Society press release NASA press release |
| Discovery of Nine Gamma-Ray Pulsars in Fermi-LAT Data Using a New Blind Search Method (Astrophysical Journal Paper) |
Max Planck Institute for Radio Astronomy press release
Albert Einstein Institute press release Max Planck Society press release NASA press release |
||
|
|
|||
| 2011/06: | |||
|
|
|||
| 2010/11: | On the nature and evolution of the binary pulsar J1903+0327 (MNRAS paper) |
Note: In this paper we find that this eccentric MSP has a 1.03 M☉ main sequence companion. The mass of the MSP is 1.667 ± 0.021 M☉ (99.7% confidence limit). Finally, is shows the system started its evolution as a triple system. | |
|
|
|||
| 2010/11: | The orthometric parameterisation of the Shapiro delay
and an improved test of general relativity with binary pulsars
(MNRAS paper) |
Note: This paper describes a Fourier decomposition of the propagational delays observed in the timing of binary pulsars. It allows a proper understanding of the constraints on companion mass and orbital inclination derived from the detection of the Shapiro delay. This results in improved mass estimation and possibly tests of general relativity if other post-Keplerian parameters are measured for the same pulsar binary. | |
|
|
|||
| 2010/09: | Pulsar Discovery by Global Volunteer Computing
(Science Paper) |
2010/08: | Albert Einstein Institute press release |
|
|
|||
| 2010/04: | The First Fermi Large Area Telescope Catalog of Gamma-ray Pulsars
(Astrophysical Journal Supplement Paper) |
Note: This paper lists the 46 gamma-ray pulsars known at the time of publication. This is really major progress compared to the six known before the launch of the Fermi satellite! | |
|
|
|||
| 2009/07: | A Population of Gamma-Ray Millisecond Pulsars
Seen with the Fermi Large Area Telescope
(Science Paper) |
2009/07: | NASA's press release. |
|
|
|||
| 2008/05: | An eccentric binary millisecond pulsar in the Galactic plane
(Science paper) |
2008/05: | Cornell University press Release
NRAO press Release |
|
|
|||
| 2007/12: | A massive neutron star in the globular cluster M5
(Astrophysical Journal Paper, in print 2008 June 1) |
2008/01: | Cornell University press Release |
|
|
|||
| 2007/11: | A 2.7-solar mass neutron star???
(Astrophysical Journal Paper, in print 2008 March 1) |
2008/01: | Sky & Telescope article on last two massive neutron star discoveries. |
|
|
|||
| 2006/09: | Most precise strong-field tests of general relativity ever
(Science paper) |
2006/09: | CSIRO press release.
Jodrell Bank Observatory press release. |
|
|
|||
| 2006/01: | Fastest spinning pulsar ever
(Science paper) |
2006/01: | NRAO press release. |
|
|
|||
| 2005/11: | The youngest binary pulsar ever found: the highly relativistic binary PSR J1906+0746
(Astrophysical Journal paper) |
2006/01: | Jodrell Bank Observatory press release
Arecibo Astronomy Highlight |
|
|
|||
| 2005/01: |
21 new millisecond pulsars in Terzan 5
(Science paper) |
2005/01: | NRAO press release. |
|
|
|||
| 2004/03: | Discovered most eccentric binary pulsar ever
(Astrophysical Journal paper) |
2005/01: | New Scientist publishes a story on some of the recent results of the GMRT, including the discovery of NGC 1851A. |
|
|
|||
| 2004/01: |
First double pulsar
(Science paper) |
2004/01: | Jodrell Bank Observatory press release.
CSIRO press release. |
|
|
|||
| 2001/10: | Science publishes a story on the discovery of gas in 47 Tucanae. | ||
| 2001/08: | Detection of ionized gas in 47 Tucanae
(Astrophysical Journal paper) |
2001/08: | Jodrell Bank Observatory press release. |
|
|
|||
| 2001/09: |
Twelve new timing solutions in 47 Tucanae
(MNRAS paper) |
Note: See why this is a cool result here. | |
|
|
|||
| 2001/04: | New method for estimating binary orbits
(MNRAS paper) |
Note: This paper describes a new method that allows the determination of very sparsely sampled pulsar orbits. See idea (and ERRATUM) here. | |
|
|
|||
| 2000/06: | Nine new millisecond pulsars in 47 Tucanae
(Astrophysical Journal paper) |
Note: See why this is a cool result here. | |
|
|
|||