Curriculum Vitae

Paulo César Carvalho Freire


This is the .html version of my CV. A printable version can be provided on demand.


Date of birth: October 1970
Place of Birth: Lisboa, Portugal
Nationality: Portuguese
e-mail: pfreire@mpifr-bonn.mpg.de
Address: Max-Planck-Institut für Radioastronomie
Auf dem Hügel 69
D-53121 Bonn, Germany
Telephone: (+49) 228 525 496
Fax: (+49) 228 525 229

Employment:

Education:

Present Research Interests:

 When the cores of massive stars run out of nuclear fuel they collapse catastrophically. Their immense gravitational field, now unopposed, compresses the core material so hard that even its atoms are destroyed. This powers a phenomenon known as a supernova.


The Crab Nebula is the remnant of a supernova that occurred in the constellation Taurus in the year 1054 AD (as seen from Earth). Credit: HST/NASA/ESA.


The supernova event marks the birth of a neutron star: a ball of neutrons, a single giant atomic nucleus with a radius of about 10-16 km and about 400 000 times the Earth's mass! Thus outside the horizons of black holes (i.e., within the Universe we can probe), neutron stars represent the most extreme astrophysical environments. Here the laws of physics are pushed to the limits of their applicability. Under such conditions, Newtonian theory no longer works even as an approximation; to calculate the basic structure of neutron stars we need general relativity from the start, plus some deep (and still incomplete) understanding of the laws of quantum mechanics and the strong nuclear force.

Pulsars are neutron stars with strong, anisotropic electromagnetic emission. For distant observers this emission is modulated by the rotation of the object, exactly like a beacon. Jocelyn Bell's discovery of radio pulsars in 1967 and the latter discovery of the fast-spinning Crab pulsar at the center of the Crab Nebula confirmed that neutron stars exist in the Universe and that they are the end products of the lives of massive stars. This discovery earned Anthony Hewish the Nobel Prize in Physics in 1974.

Pulsars are superb tools for the study of fundamental physics! The reasons for this are manifold:

Here is a list of fundamental questions that can be addressed with pulsar timing.:
  1. Did Einstein have the last word on Gravity? General relativity - the current, unsurpassed description of gravity - is fundamentally incompatible with quantum mechanics. This makes any attempts at unifying gravity with the other forces of Nature problematic. Furthermore, alternative theories of gravity have been proposed to explain the rotational curves of galaxies and clusters without the need for Dark Matter, universal acceleration without the need for Dark Energy and Cosmic Inflation (fundamental for understanding the origin of the Universe).

    Is gravity really responsible for these phemomena? Clearly, understanding it is important not only for understanding the laws of Nature, but also the origin, evolution and contents the Universe!

    In order to answer this question, I am leading the construction of an Ultra Broad-Band receiver (BEACON) for the 100-m Effelsberg radio telescope. This will have a frequency coverage from 0.6 to 2.6 GHz, and will be complemented with an ultra broadband coherent dedispersion system. This new observing system will be used for timing pulsars with unprecedented sensitivity and accuracy. It is being funded by the European Research Council through my BEACON, grant!
    Binary pulsars are especially useful for answering this question because they provide the only strong-field tests of gravitational theories. Russel Hulse and Joe Taylor earned the Nobel Prize in Physics in 1993 for their discovery of the first binary pulsar, PSR B1913+16. Precise measurements of the orbital motion of this object with the Arecibo radio telescope confirmed the existence of gravitational waves (GWs), a fundamental prediction of general relativity (GR).
    Since then tests of general relativity with other binary systems (listed below) have become so precise that we can exclude some of these alternative theories of gravity!
    The new BEACON observing system will greatly improve the precision of these tests, leading to ever-tightening constraints on alternative theories of gravity - or a falsification of general relativity itself! In either case, a better understanding of the laws of physics and the contents of the Universe.
    It will also provide significantly improved mass measurements for many neutron stars and help with the detection of gravitational waves (see below).
    In 2000, I helped the Parkes High-Latitude Survey get started. This survey discovered the double pulsar. After only three years of timing, this system yielded the most precise strong-field tests of general relativity ever!
    The measurement of the mass of PSR J1738+0333 and of its white dwarf companion allowed the most stringent test of scalar-tensor theories of gravity! Ever! Combining the upcoming results from the double pulsar (PSR J0737−3039) this those from PSR J1738+0333, we will be able to exclude a wide class of theories based on TeVeS.



    Left: Solar-system and binary pulsar 1-σ constraints on the matter-scalar coupling constants α0 and β0 of Scalar-Tensor theories of gravity. Note that a logarithmic scale is used for the vertical axis |α0|, i.e., that GR (α0 = β0 = 0) is sent at an infinite distance down this axis. The Jordan-Fierz-Brans-Dicke class of theories is represented in the vertical axis (β0 = 0). LLR stands for lunar laser ranging, Cassini for the measurement of a Shapiro time-delay variation in the Solar System, and SEP for tests of the strong equivalence principle using a set of neutron star-white dwarf low-eccentricity binaries. The allowed region is shaded, and it includes general relativity. PSR J1738+0333 is the most constraining binary pulsar, although the Cassini bound is still better for a finite range of quadratic coupling β0.
    Right: Similar theory plane as on the left, but now for the (non-conformal) matter-scalar coupling described in the paper, generalizing Bekenstein's TeVeS model (here represented by the vertical axis, β0 = 0). Above the upper horizontal dashed line, the nonlinear kinetic term of the scalar field may be a natural function; between the two dashed lines, this function needs to be tuned; and below the lower dashed line, it cannot exist any longer. The allowed region is shaded. It excludes general relativity (α0 = β0 = 0) because such models are built to predict modified Newtonian dynamics (MOND) at large distances. Note that binary pulsars are more constraining than Solar-System tests for this class of models (and that the Cassini bound on the left Figure does not exist any longer here). For a generic nonzero β0, PSR J1738+0333 is again the most constraining binary pulsar, while for β0 ~ 0, the magnitude of |α0| is bounded by the J0737−3039 system. Plots made by Gilles Esposito-Farèse.
    Myself, Michael Kramer and Norbert Wex have just proposed a new, ever-improving test of the Strong Equivalence Principle. This is based on the measurement of the variation of the orbital eccentricity, an effect that is remarkably free of pollution by other physical effects.
    Together with Norbert Wex, I have devised a new parameterization of the Shapiro delay in binary pulsars. This provides a superior description of the constraints introduced by Shapiro delay measurements and, because of that, a much improved test of general relativity for some binary pulsars!
    I am one of the contributors to Arecibo's ALFA pulsar survey. This survey discovered the youngest binary pulsar, PSR J1906+0746; which is also the second most relativistic system known. It belongs to a new population of young, binary systems that could include even more eccentric and compacts orbits!


  2. Pulsars will also be important for the direct detection of gravitational waves:
    Fast-spinning pulsars might be detectable with GW detectors like LIGO and VIRGO
    Precise timing of bright millisecond pulsars might detect low-frequency GWs in the near future.


  3. What are the new states of matter at exceedingly high density and temperature?
    Matter at the center of neutron stars is much denser than atomic nuclei. The composition and behavior of matter in these conditions is not precisely known.
    Measurements of masses and (high) spin frequencies of neutron stars introduces strong constraints on the properties of super-dense matter.
    In a statistical study of the masses of some binary pulsars in globular clusters (Terzan 5 I and J, M5 B, and NGC 6440B) we found strong evidence for the existence of neutron stars with masses larger than 1.4 M☉, the famous Chandrasekhar Limit.
    This was confirmed when the PALFA survey discovered PSR J1903+0327, the first Galactic MSP with an eccentric orbit and the first known to have a main-sequence companion! The high eccentricity of the orbit and a strong measurement of the Shapiro delay allowed the first precise measurement of a neutron star mass above the Chandrasekhar limit: 1.667 ± 0.021 M☉ (99.7% confidence limit), a value that excludes several proposed equations of state for dense matter.
    This upper mass limit has since been superseded by the mass measurement of PSR J1614−2230, which introduces much more stringent constraints, but it is still more precise.
    In our survey of the globular cluster Terzan 5, we discovered the fastest spinning pulsar known, breaking a 24-year old record. Not quite fast enough to exclude equations of state for dense matter, but still very cool!



    The globular cluster 47 Tucanae harbours at least 23 millisecond pulsars. Picture used with permission of its author, Robert Gendler.


  4. What is the Population of Pulsars in Globular Clusters? Many of the systems I use to address these questions were discovered in globular clusters. These old, dense star clusters are great millisecond pulsar factories. Many of these objects are exotic binary pulsars that are impossible to find in the Galactic disk, as they can not beformed by the known mechanisms of stellar evolution - they were formed instead by exchange encounters. Because they formed differently, they can have unusual (and in some cases useful!) properties:
    For my Ph.D. Thesis I helped searching and led the timing of the pulsars in 47 Tucanae. This allowed X-ray follow-up of these MSPs, a study of the dynamics of the cluster and the first detection of any sort of interstellar medium in a globular cluster, after more than 60 years of searches!
    In 2004, I discovered NGC1851A, then the most eccentric binary pulsar known. This system probably formed as a "normal" millisecond pulsar - light white dwarf binary, which was later disrupted by the intrusion of the present massive companion. This is the exact mechanism for the creation of MSP - black hole or MSP-MSP systems! This is one of the reasons why we keep searching for pulsars in globular clusters!
    As a result of these searches, we discovered a dozen more eccentric binaries like NGC 1851A. The eccentricites of these systems allow mass measurements that in some cases are useful for studies of the equation of state of dense matter (see Terzan 5 I, J, M5B and NGC 6440B above). In one recent case, NGC 6544B, we made the most precise measurement ever of the mass of a millisecond pulsar.


  5. What is the population of Gamma-ray pulsars? The Launch of the Fermi Gamma-ray Space Telescope has been one of the major developments in pulsar science in the last few years. Previously, only seven pulsars were known to emit gamma rays, but with the Large Area Telescope on board Fermi we now know many more. Here is an updated list with more than 100 pulsars!

    This great success has in part been possible because of the symbiotic collaboration between radio and gamma-ray astronomers:
    A first step we timed radio pulsars that were suspected of having strong gamma-ray emission. After the launch of Fermi, many of these were confirmed as gamma-ray pulsars; a task made much easier by the availability of radio ephemerides.
    Fermi also discovered that several millisecond pulsars are gamma-ray emitters! Even millisecond pulsars in globular clusters are now appearing as gamma-ray pulsars.
    In a second phase, many new gamma-ray pulsars are being found from their gamma-ray emission alone! Most of these have not been detected at radio wavelengths, but some were: here I contributed with the detection of the faintest young radio pulsar known.
    In a third phase, many Fermi sources that had low variability and sharp cutoffs in the spectra (characteristics of gamma-ray pulsars) could be so well localized in space that we could use radiotelescopes to search efficiently for radio pulsars in these sources. Many of them are now revealing new pulsars. Most of these are millisecond pulsars, and most of those are in binary systems, which explains why their pulsations could not detected in gamma rays. After deriving a radio timing ephemeris, we can see their gamma-ray pulses.
    As a result of these searches, we know a lot more about the population of neutron stars in the Galaxy and about the mechanism of gamma-ray emission. No doubt many more gamma-ray pulsars remain to be found by the Fermi LAT!


Refereed Publications
Total of 89 refereed publications (ADS search definition).
Papers from conference proceedings are indicated with an asterisk.
1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012

2012
arXiv:1205.3751 05/2012
P. C. C. Freire, M. Kramer and N. Wex Tests of the universality of free fall for strongly self-gravitating bodies with radio pulsars
arXiv:1205.1450 05/2012
P. C. C. Freire, N. Wex, G. Esposito-Farèse, J. P. W. Verbiest, M. Bailes, B. A. Jacoby, M. Kramer, I. H. Stairs, J. Antoniadis, G. H. Janssen The relativistic pulsar-white dwarf binary PSR J1738+0333 II. The most stringent test of scalar-tensor gravity
arXiv:1204.3948 04/2012
J. Antoniadis, M. H. van Kerkwijk, D. Koester, P. C. C. Freire, N. Wex, T. M. Tauris, M. Kramer, C. G. Bassa The relativistic pulsar-white dwarf binary PSR J1738+0333 I. Mass determination and evolutionary history
arXiv:1201.6641 01/2012
P. B. Demorest, R. D. Ferdman, M. E. Gonzalez, D. Nice, S. Ransom, I. H. Stairs, Z. Arzoumanian, A. Brazier, S. Burke-Spolaor, S. J. Chamberlin, J. M. Cordes, J. Ellis, L. S. Finn, P. Freire, S. Giampanis, F. Jenet, V. M. Kaspi, J. Lazio, A. N. Lommen, M. McLaughlin, N. Palliyaguru, D. Perrodin, R. M. Shannon, X. Siemens, D. Stinebring, J. Swiggum, W. W. Zhu Limits on the Stochastic Gravitational Wave Background from the North American Nanohertz Observatory for Gravitational Waves
2012MNRAS.422.1294G 05/2012
L. Guillemot, P. C. C. Freire, I. Cognard, T. J. Johnson, Y. Takahashi, J. Kataoka, G. Desvignes, F. Camilo, E. C. Ferrara, A. K. Harding, G. H. Janssen, M. Keith, M. Kerr, M. Kramer, D. Parent, S. M. Ransom, P. S. Ray, P. M. Saz Parkinson, D. A. Smith, B. W. Stappers, G. Theureau Discovery of the millisecond pulsar PSR J2043+1711 in a Fermi source with the Nancay Radio Telescope
2012ApJ...747...64T 03/2012
Y. Takahashi, J. Kataoka, T. Nakamori, K. Maeda, R. Makiya, T. Totani, C. C. Cheung, L. Stawarz, L. Guillemot, P. C. C. Freire, I. Cognard Suzaku X-ray Follow-up Observations of Seven Unassociated Fermi-LAT Gamma-ray Sources at High Galactic Latitudes
2012ApJ...746...39C 02/2012
F. Camilo, M. Kerr, P.S. Ray, S.M. Ransom, S. Johnston, R.W. Romani, D. Parent, M.E. DeCesar, A.K. Harding, D. Donato, P.M. Saz Parkinson, E.C. Ferrara, P.C.C. Freire, L. Guillemot, M. Keith, M. Kramer, K.S. Wood PSR J2030+3641: radio discovery and gamma-ray study of a middle-aged pulsar in the now identified Fermi-LAT source 1FGL J2030.0+3641
2012ApJ...745..109L 02/2012
Ryan S. Lynch, Paulo C. C. Freire, Scott M. Ransom, Bryan A. Jacoby The Timing of Nine Globular Cluster Pulsars
2012ApJ...744..105P 01/2012
H. J. Pletsch, L. Guillemot, B. Allen, M. Kramer, C. Aulbert, H. Fehrmann, P. S. Ray, E. D. Barr, A. Belfiore, F. Camilo, P. A. Caraveo, O. Celik, D. J. Champion, M. Dormody, R. P. Eatough, E. C. Ferrara, P. C. C. Freire, J. W. T. Hessels, M. Keith, M. Kerr, A. de Luca, A. G. Lyne, M. Marelli, M. A. McLaughlin, D. Parent, S. M. Ransom, M. Razzano, W. Reich, P. M. Saz Parkinson, B. W. Stappers, M. T. Wolff Discovery of Nine Gamma-Ray Pulsars in Fermi Large Area Telescope Data Using a New Blind Search Method
2012ApJ...744...33G 01/2012
L. Guillemot, T. J. Johnson, C. Venter, M. Kerr, B. Pancrazi, M. Livingstone, G. H. Janssen, P. Jaroenjittichai, M. Kramer, I. Cognard, B. W. Stappers, A. K. Harding, F. Camilo, C. M. Espinoza, P. C. C. Freire, F. Gargano, J. E. Grove, S. Johnston, P. F. Michelson, A. Noutsos, D. Parent, S. M. Ransom, P. S. Ray, R. Shannon, D. A. Smith, G. Theureau, S. E. Thorsett, N. Webb Pulsed Gamma Rays from the Original Millisecond and Black Widow Pulsars: a case for Caustic Radio Emission?

2011
2011ApJ...743..170P 12/2011
D. Parent, M. Kerr, P. R. Den Hartog, M. G. Baring, M. E. DeCesar, C. M. Espinoza, E. V. Gotthelf, A. K. Harding, S. Johnston, V. M. Kaspi, M. Livingstone, R. W. Romani, B. W. Stappers, K. Watters, P. Weltevrede, A. A. Abdo, M. Burgay, F. Camilo, H. A. Craig, P. C. C. Freire, F. Giordano, L. Guillemot, G. Hobbs, M. Keith, M. Kramer, A. G. Lyne, R. N. Manchester, A. Noutsos, A. Possenti, D. A. Smith Observations of Energetic High Magnetic Field Pulsars with the Fermi Large Area Telescope
2011ApJ...743..102G 12/2011
M. E. Gonzalez, I. H. Stairs, R. D. Ferdman, P. C. C. Freire, D. J. Nice, P. B. Demorest, S. M. Ransom, M. Kramer, F. Camilo, G. Hobbs, R. N. Manchester, A. G. Lyne High-Precision Timing of 5 Millisecond Pulsars: Space Velocities, Binary Evolution and Equivalence Principles
2011Sci...334.1107F 11/2011
Paulo C. C. Freire and the Fermi-LAT Collaboration Fermi Detection of a Luminous γ-Ray Pulsar in a Globular Cluster
2011ApJ...742...51B 11/2011
Jason Boyles, Duncan R. Lorimer, Phil J. Turk, Robert Mnatsakanov, Ryan S. Lynch, Scott M. Ransom, Paulo C. Freire, Khris Belczynski Young Radio Pulsars in Galactic Globular Clusters
2011A&A...533A.102L 09/2011
M. Lemoine-Goumard, V. E. Zavlin, M.-H. Grondin, R. Shannon, D. A. Smith, M. Burgay, F. Camilo, J. Cohen-Tanugi, P. C. C. Freire, J. E. Grove, L. Guillemot, S. Johnston, M. Keith, M. Kramer, R. N. Manchester, P. F. Michelson, D. Parent, A. Possenti, P. S. Ray, M. Renaud, S. E. Thorsett, P. Weltevrede, M. T. Wolff Discovery of gamma and X-ray pulsations from the young and energetic PSR J1357-6429 with Fermi and XMM-Newton
2011ApJ...738...42G 09/2011
M.-H. Grondin, S. Funk, M. Lemoine-Goumard, A. Van Etten, J. A. Hinton, F. Camilo, I. Cognard, C. M. Espinoza, P. C. C. Freire, J. E. Grove, L. Guillemot, S. Johnston, M. Kramer, J. Lande, P. Michelson, A. Possenti, R. W. Romani, J. L. Skilton, G. Theureau, P. Weltevrede Detection of the Pulsar Wind Nebula HESS J1825-137 with the Fermi Large Area Telescope
2011MNRAS.414.1292K 06/2011
M. J. Keith, S. Johnston, P. S. Ray, E. C. Ferrara, P. M. Saz Parkinson, Ö. Çelik, A. Belfiore, D. Donato, C. C. Cheung, A. A. Abdo, F. Camilo, P. C. C. Freire, L. Guillemot, A. K. Harding, M. Kramer, P. F. Michelson, S. M. Ransom, R. W. Romani, D. A. Smith, D. J. Thompson, P. Weltevrede, K. S. Wood Discovery of millisecond pulsars in radio searches of southern Fermi LAT sources
2011ApJS..194...17R 06/2011
P. S. Ray, M. Kerr, D. Parent, A. A. Abdo, L. Guillemot, S. M. Ransom, N. Rea, M. T. Wolff, A. Makeev, F. Camilo, M. Dormody, P. C. C. Freire, J. E. Grove, C. Gwon, A. K. Harding, S. Johnston, M. Keith, M. Kramer, P. F. Michelson, P. M. Saz Parkinson, R. W. Romani, D. J. Thompson, P. Weltevrede, K. S. Wood, M. Ziegler Precise Gamma-Ray Timing and Radio Observations of 17 Fermi Gamma-Ray Pulsars
2011ApJ...734...89L 06/2011
Ryan S. Lynch, Scott M. Ransom, Paulo C. C. Freire, Ingrid H. Stairs Six New Recycled Globular Cluster Pulsars Discovered with the Green Bank Telescope
2011ApJ...732...47C 05/2011
I. Cognard, L. Guillemot, T. J. Johnson, D. A. Smith, C. Venter, A. K. Harding, M. T. Wolff, C. C. Cheung, D. Donato, A. A. Abdo, J. Ballet, F. Camilo, G. Desvignes, D. Dumora, E. C. Ferrara, P. C. C. Freire, J. E. Grove, M. Keith, M. Kramer, A. G. Lyne, P. F. Michelson, D. Parent, S. M. Ransom, P. S. Ray, R. W. Romani, P. M. Saz Parkinson, B. W. Stappers, G. Theureau, D. J. Thompson, P. Weltevrede, K. S. Wood Discovery of two millisecond pulsars in Fermi sources with the Nancay Radio Telescope
2011ApJ...732L...1K 05/2011
B. Knispel, P. Lazarus, B. Allen, D. Anderson, C. Aulbert, N. D. R. Bhat, O. Bock, S. Bogdanov, A. Brazier, F. Camilo, S. Chatterjee, J. M. Cordes, F. Crawford, J. S. Deneva, G. Desvignes, H. Fehrmann, P. C. C. Freire, D. Hammer, J. W. T. Hessels, F. A. Jenet, V. M. Kaspi, M. Kramer, J. van Leeuwen, D. R. Lorimer, A. G. Lyne, B. Machenschalk, M. A. McLaughlin, C. Messenger, D. J. Nice, M. A. Papa, H. J. Pletsch, R. Prix, S. M. Ransom, X. Siemens, I. H. Stairs, B. W. Stappers, K. Stovall, A. Venkataraman Arecibo PALFA Survey and Einstein@Home: Binary Pulsar Discovery by Volunteer Computing
2011MNRAS.412.2763F 04/2011
P. C. C. Freire, C. G. Bassa, N. Wex, I. H. Stairs, D. J. Champion, S. M. Ransom, P. Lazarus, V. M. Kaspi, J. W. T. Hessels, M. Kramer, J. M. Cordes, J. P. W. Verbiest, P. Podsiadlowski, D. J. Nice, J. S. Deneva, D. R. Lorimer, B. W. Stappers, M. A. McLaughlin, F. Camilo On the nature and evolution of the unique binary pulsar J1903+0327
2011ApJ...730...81B 04/2011
Slavko Bogdanov, Maureen van den Berg, Mathieu Servillat, Craig O. Heinke, Jonathan E. Grindlay, Ingrid H. Stairs, Scott M. Ransom, Paulo C. C. Freire, Steve Bégin, Werner Becker Chandra X-ray Observations of 12 Millisecond Pulsars in the Globular Cluster M28
2011ApJ...728...77N 01/2011
A. Noutsos, A. A. Abdo and Fermi Pulsar Timing Consortium Radio and Gamma-Ray Constraints on the Emission Geometry and Birthplace of PSR J2043+2740
2011ApJ...727L..16R 01/2011
S. M. Ransom, P. S. Ray, F. Camilo, M. S. E. Roberts, O. Celik, M. T. Wolff, C. C. Cheung, M. Kerr, T. Pennucci, M. E. DeCesar, I. Cognard, A. G. Lyne, B. W. Stappers, P. C. C. Freire, J. E. Grove, A. A. Abdo, G. Desvignes, D. Donato, E. C. Ferrara, N. Gehrels, L. Guillemot, C. Gwon, A. K. Harding, S. Johnston, M. Keith, M. Kramer, P. F. Michelson, D. Parent, P. M. Saz Parkinson, R. W. Romani, D. A. Smith, G. Theureau, D. J. Thompson, P. Weltevrede, K. S. Wood, M. Ziegler Three Millisecond Pulsars in FERMI LAT Unassociated Bright Sources

2010
2010ApJ...725.1165P 12/2010
C. Pallanca, E. Dalessandro, F.R. Ferraro, B. Lanzoni, R.T. Rood, A. Possenti, N. D'Amico, P.C. Freire, I. Stairs, S.M. Ransom, S. Begin The optical companion to the binary millisecond pulsar J1824−2452H in the globular cluster M28
2010ApJ...725..571S 12/2010
P.M. Saz Parkinson, M. Dormody, M. Ziegler, P.S. Ray, A.A. Abdo, J. Ballet, M.G. Baring, A. Belfiore, T.H. Burnett, G.A. Caliandro, F. Camilo, P.A. Caraveo, A. de Luca, E.C. Ferrara, P.C.C. Freire, J.E. Grove, C. Gwon, A.K. Harding, R.P. Johnson, T.J. Johnson, S. Johnston, M. Keith, M. Kerr, J. Knödlseder, A. Makeev, M. Marelli, P.F. Michelson, D. Parent, S.M. Ransom, O. Reimer, R.W. Romani, D.A. Smith, D.J. Thompson, K. Watters, P. Weltevrede, M.T. Wolff, K.S. Wood Eight gamma-ray pulsars discovered in blind frequency searches of Fermi LAT data
2010MNRAS.409..199F 11/2010
P.C.C. Freire, Norbert Wex The orthometric parameterisation of the Shapiro delay and an improved test of general relativity with binary pulsars
2010ApJ...721.1193P 10/2010
B. Perera, M. A. McLaughlin, M. Kramer, I. H. Stairs, R. Ferdman, P. C. C. Freire, A. Possenti, R. Breton, R. N. Manchester, M. Burgay, A. G. Lyne, F. Camilo The Evolution of PSR J0737−3039B and a Model for Relativistic Spin Precession
2010Sci...329.1305K (see arXiv:1008.2172v1) 09/2010
B. Knispel, B. Allen, J. M. Cordes, J. S. Deneva, D. Anderson, C. Aulbert, N. D. R. Bhat, O. Bock, S. Bogdanov, A. Brazier, F. Camilo, D. J. Champion, S. Chatterjee, F. Crawford, P. B. Demorest, H. Fehrmann, P. C. C. Freire, M. E. Gonzalez,D. Hammer, J. W. T. Hessels, F. A. Jenet, L. Kasian, V. M. Kaspi, M. Kramer, P. Lazarus, J. van Leeuwen, D. R. Lorimer, A. G. Lyne, B. Machenschalk, M. A. McLaughlin, C. Messenger, D. J. Nice, M. A. Papa, H. J. Pletsch, R. Prix, S. M. Ransom, X. Siemens, I. H. Stairs, B. W. Stappers, K. Stovall, A. Venkataraman Pulsar Discovery by Global Volunteer Computing
2010ApJ...720...26A 08/2010
Fermi LAT Collaboration, Fermi Pulsar Timing Consortium (A. A. Abdo et al.) Fermi Large Area Telescope Observations of Gamma-ray Pulsars PSR J1057−5226, J1709−4429, and J1952+3252
2010CQGra..27h4013H* 04/2010
Hobbs, G.; Archibald, A.; Arzoumanian, Z.; Backer, D.; Bailes, M.; Bhat, N. D. R.; Burgay, M.; Burke-Spolaor, S.; Champion, D.; Cognard, I.; Coles, W.; Cordes, J.; Demorest, P.; Desvignes, G.; Ferdman, R. D.; Finn, L.; Freire, P.; Gonzalez, M.; Hessels, J.; Hotan, A.; Janssen, G.; Jenet, F.; Jessner, A.; Jordan, C.; Kaspi, V.; Kramer, M.; Kondratiev, V.; Lazio, J.; Lazaridis, K.; Lee, K. J.; Levin, Y.; Lommen, A.; Lorimer, D.; Lynch, R.; Lyne, A.; Manchester, R.; McLaughlin, M.; Nice, D.; Oslowski, S.; Pilia, M.; Possenti, A.; Purver, M.; Ransom, S.; Reynolds, J.; Sanidas, S.; Sarkissian, J.; Sesana, A.; Shannon, R.; Siemens, X.; Stairs, I.; Stappers, B.; Stinebring, D.; Theureau, G.; van Haasteren, R.; van Straten, W.; Verbiest, J. P. W.; Yardley, D. R. B.; You, X. P. The international pulsar timing array project: using pulsars as a gravitational wave detector
2010ApJS..187..460A 04/2010
Fermi LAT Collaboration, Fermi Pulsar Timing Consortium (A. A. Abdo et al.) The First Fermi Large Area Telescope Catalog of Gamma-ray Pulsars
2010ApJ...713..671A 04/2010
LIGO collaboration + S. Bégin, A. Corongiu, N. D'Amico, P. C. C. Freire, J. Hessels, G. B. Hobbs, M. Kramer, A. G. Lyne, R. N. Manchester, F. E. Marshall, J. Middleditch, A. Possenti, S. M. Ransom, I. H. Stairs, and B. Stappers Searches for gravitational waves from known pulsars with S5 LIGO data
2010ApJ...712..957A 04/2010
Fermi LAT Collaboration, Fermi Pulsar Timing Consortium (A. A. Abdo et al.) Discovery of Pulsed gamma-rays from PSR J0034−0534 with the Fermi LAT: A Case for Co-located Radio and gamma-ray Emission Regions
2010ApJ...711...64A 03/2010
Fermi LAT Collaboration, Fermi Pulsar Timing Consortium (A. A. Abdo et al.) PSR J1907+0602: A Radio-Faint Gamma-Ray Pulsar Powering a Bright TeV Pulsar Wind Nebula
2010ApJ...708.1426W 01/2010
The Fermi LAT collaboration, the Fermi Pulsar Timing Consortium (P.Weltevrede, A.A. Abdo, et al) Gamma-ray and Radio Properties of Six Pulsars Detected by the Fermi Large Area Telescope
2010ApJ...708.1254A 01/2010
Fermi LAT Collaboration, Fermi Pulsar Timing Consortium (A. A. Abdo et al.) Fermi Large Area Telescope Observations of the Crab Pulsar and Nebula

2009
2009ApJ...706.1331A 12/2009
Fermi LAT Collaboration, Fermi Pulsar Timing Consortium (A. A. Abdo et al.) Fermi Large Area Telescope Detection of Pulsed gamma-rays from the Vela-like Pulsars PSR J1048−5832 and PSR J2229+6114
2009ApJ...705....1C 11/2009
Camilo, F.; Ray, P. S.; Ransom, S. M.; Burgay, M.; Johnson, T. J.; Kerr, M.; Gotthelf, E. V.; Halpern, J. P.; Reynolds, J.; Romani, R. W.; Demorest, P.; Johnston, S.; van Straten, W.; Saz Parkinson, P. M.; Ziegler, M.; Dormody, M.; Thompson, D. J.; Smith, D. A.; Harding, A. K.; Abdo, A. A.; Crawford, F.; Freire, P. C. C.; Keith, M.; Kramer, M.; Roberts, M. S. E.; Weltevrede, P.; Wood, K. S. Radio Detection of LAT PSRs J1741−2054 and J2032+4127: No Longer Just Gamma-ray Pulsars
2009ApJ...703.2259D 10/2009
Deneva, J. S.; Cordes, J. M.; Mc Laughlin, M. A.; Nice, D. J.; Lorimer, D. R.; Crawford, F.; Bhat, N. D. R.; Camilo, F.; Champion, D. J.; Freire, P. C. C.; Edel, S.; Kondratiev, V. I.; Hessels, J. W. T.; Jenet, F. A.; Kasian, L.; Kaspi, V. M.; Kramer, M.; Lazarus, P.; Ransom, S. M.; Stairs, I. H.; Stappers, B. W.; van Leeuwen, J.; Brazier, A.; Venkataraman, A.; Zollweg, J. A.; Bogdanov, S. Arecibo Pulsar Survey Using ALFA: Probing Radio Pulsar Intermittency And Transients
2009A&A...504..673M 09/2009
Mion, A.; Benacquista, M. J.; Kramer, M.; Freire, P. P. C.; Possenti, A. A search for periodic gravitational waves from three recycled pulsars using the AURIGA detector. An implementation of a modified version of the unified approach method
2009Sci...325..848A 08/2009
Fermi LAT Collaboration, Fermi Pulsar Timing Consortium (A. A. Abdo et al.) A Population of Gamma-Ray Millisecond Pulsars Seen with the Fermi Large Area Telescope
2009ApJ...700.1059A 08/2009
Fermi LAT Collaboration, Fermi Pulsar Timing Consortium (A. A. Abdo et al.) Pulsed Gamma-rays from PSR J2021+3651 with the Fermi Large Area Telescope
2009ApJ...700L.123A 08/2009
Agüeros, Marcel A.; Heinke, Craig; Camilo, Fernando; Kilic, Mukremin; Anderson, Scott F.; Freire, Paulo; Kleinman, Scot J.; Liebert, James W.; Silvestri, Nicole M. No Neutron Star Companion To The Lowest Mass SDSS White Dwarf
2009ApJ...699L.102A 07/2009
Fermi LAT Collaboration, Fermi Pulsar Timing Consortium (A. A. Abdo et al.) Discovery of Pulsations from the Pulsar J0205+6449 in SNR 3C 58 with the Fermi Gamma-Ray Space Telescope
2009MNRAS.396.1764F 07/2009
P. C. C. Freire, N. Wex, M. Kramer, D. R. Lorimer, M. A. McLaughlin, I. H. Stairs, R. Rosen, A. G. Lyne A new technique for timing the double pulsar system
2009ApJ...696.1084A 05/2009
Fermi LAT Collaboration, Fermi Pulsar Timing Consortium (A. A. Abdo et al.) Fermi Large Area Telescope Observations of the Vela Pulsar

2008
2008A&A...492..923S 12/2008
D. A. Smith, L. Guillemot, F. Camilo, I. Cognard, D. Dumora, C. Espinoza, P. C. C. Freire, E. V. Gotthelf, A. K. Harding, G. B. Hobbs, S. Johnston, V. M. Kaspi, M. Kramer, M. A. Livingstone, A. G. Lyne, R. N. Manchester, F. E. Marshall, M. A. McLaughlin, A. Noutsos, S. M. Ransom, M. S. E. Roberts, R. W. Romani, B. W. Stappers, G. Theureau, D. J. Thompson, S. E. Thorsett, N. Wang, P. Weltevrede Pulsar Timing for the Fermi Gamma-ray Space Telescope
2008ApJ...682L..41H 07/2008
Hessels, J. W. T.; Nice, D. J.; Gaensler, B. M.; Kaspi, V. M.; Lorimer, D. R.; Champion, D. J.; Lyne, A. G.; Kramer, M.; Cordes, J. M.; Freire, P. C. C.; Camilo, F.; Ransom, S. M.; Deneva, J. S.; Bhat, N. D. R.; Cognard, I.; Crawford, F.; Jenet, F. A.; Kasian, L.; Lazarus, P.; van Leeuwen, J.; McLaughlin, M. A.; Stairs, I. H.; Stappers, B. W.; Venkataraman, A. PSR J1856+0245: Arecibo Discovery of a Young, Energetic Pulsar Coincident with the TeV gamma-Ray Source HESS J1857+026
2008Sci...320.1309C 06/2008
D. J. Champion, S. M. Ransom, P. Lazarus, F. Camilo, C. Bassa, V. M. Kaspi, D. J. Nice, P. C. C. Freire, I. H. Stairs, J. van Leeuwen, B. W. Stappers, J. M. Cordes, J. W. T. Hessels, D. R. Lorimer, Z. Arzoumanian, D. C. Backer, N. D. Ramesh Bhat, S. Chatterjee, I. Cognard, J. S. Deneva, C.-A. Faucher-Guiguère, B. M. Gaensler, J. Han, F. A. Jenet, L. Kasian, V. I. Kondratiev, M. Kramer, J. Lazio, M. A. McLaughlin, A. Venkataraman & W. Vlemmings An Eccentric Binary Millisecond Pulsar in the Galactic Plane
2008ApJ...679.1433F 06/2008
Paulo C. C. Freire, Alex Wolszczan, Maureen van den Berg, Jason W. T. Hessels A Massive Neutron Star in the Globular Cluster M5
2008ApJ...675..670F 03/2008
Paulo C. C. Freire, Scott M. Ransom, Steve Bégin, Ingrid H. Stairs, Jason W. T. Hessels, Lucille H. Frey, and Fernando Camilo Eight New Millisecond Pulsars in NGC 6440 and NGC 6441

2007
2007A&AT...26..541R* 12/2007
Rickett, B.; Coles, B.; McLaughlin, M.; Bank, J.; Lyne, A.; Stairs, I.; Ferdman, R.; Freire, P.; Camilo, F. Interstellar scintillation of the double pulsar J0737−3039: effects of anisotropy
2007ApJ...670..363H 11/2007
J.W.T. Hessels, S.M. Ransom, I.H. Stairs, V.M. Kaspi, P.C.C. Freire A 1.4-GHz Arecibo Survey for Pulsars in Globular Clusters
2007MNRAS.379.1217L 08/2007
D. R. Lorimer, P. C. C. Freire, I. H. Stairs, M. Kramer, M. McLaughlin, M. Burgay, S. Thorsett, R. Dewey, A. G. Lyne, R. N. Manchester, N. D'Amico, A. Possenti and B. C. Joshi Age constraints in the double pulsar system J0737−3039
2007ApJ...662.1177F 06/2007
P. C. C. Freire, S. M. Ransom and Y. Gupta Timing the Eccentric Binary Millisecond Pulsar in NGC 1851

2006
2006ChJAS...6b.311V * 12/2006
van Leeuwen, J.; Cordes, J. M.; Lorimer, D. R.; Freire, P. C. C.; Camilo, F.; Stairs, I. H.; Nice, D. J.; Champion, D. J.; Ramachandran, R.; Faulkner, A. J.; Lyne, A. G.; Ransom, S. M.; Arzoumanian, Z.; Manchester, R. N.; McLaughlin, M. A.; Hessels, J. W. T.; Vlemmings, W.; Deshpande, A. A.; Bhat, N. D. R.; Chatterjee, S.; Han, J. L.; Gaensler, B. M.; Kasian, L.; Deneva, J. S.; Reid, B.; Lazio, T. J. W.; Kaspi, V. M.; Crawford, F.; Lommen, A. N.; Backer, D. C.; Kramer, M.; Stappers, B. W.; Hobbs, G. B.; Possenti, A.; D'Amico, N.; Faucher-Giguère, C.-A.; Burgay, M. Arecibo and the ALFA Pulsar Survey
2006Sci...314...97K 10/2006
M. Kramer, I. H. Stairs, R. N. Manchester, M. A. McLaughlin, A. G. Lyne, R. D. Ferdman, M. Burgay, D. R. Lorimer, A. Possenti, N. D'Amico, J. M. Sarkissian, G. B. Hobbs, J. E. Reynolds, P. C. C. Freire, F. Camilo Tests of General Relativity from Timing the Double Pulsar
2006ApJ...646.1104B 08/2006
Slavko Bogdanov, Jonathan E. Grindlay, Craig O. Heinke, Fernando Camilo, Paulo C. C. Freire, Werner Becker Chandra X-Ray Observations of Nineteen Millisecond Pulsars in the Globular Cluster 47 Tucanae
2006MNRAS.368..283B 05/2006
Burgay, M.; Joshi, B. C.; D'Amico, N.; Possenti, A.; Lyne, A. G.; Manchester, R. N.; McLaughlin, M. A.; Kramer, M.; Camilo, F.; Freire, P. C. C. The Parkes High-Latitude pulsar survey
2006Sci...311.1901H 03/2006
Jason W. T. Hessels, Scott M. Ransom, Ingrid H. Stairs, Paulo C. C. Freire, Victoria M. Kaspi, Fernando Camilo A Radio Pulsar Spinning at 716 Hz
2006ApJ...640..428L 03/2006
D. R. Lorimer, I. H. Stairs, P. C. C. Freire, J. M. Cordes, F. Camilo, A. J. Faulkner, A. G .Lyne, D. J. Nice, S. M. Ransom, Z. Arzoumanian, R. N. Manchester, D. J. Champion, J. van Leeuwen, M. A. McLaughlin, R. Ramachandran, J. W. T. Hessels, W. Vlemmings, A. A. Deshpande, N. D. R. Bhat, S. Chatterjee, J. L. Han, B. M. Gaensler, L. Kasian, J. S. Deneva, B. Reid, T. J. W. Lazio, V. M. Kaspi, F .Crawford, A. N. Lommen, D. C. Backer, M. Kramer, B. W. Stappers, G. B. Hobbs, A. Possenti, N. D'Amico and M. Burgay Arecibo Pulsar Survey Using ALFA. II. The young, highly relativistic binary pulsar J1906+0746
2006ApJ...637..446C 01/2006
J. M. Cordes, P. C. C. Freire, D. R. Lorimer, F. Camilo, D. J. Champion, D. J. Nice, R. Ramachandran, J. W. T. Hessels, W. Vlemmings, J. van Leeuwen, S. M. Ransom, N. D. R. Bhat, Z. Arzoumanian, M. A. McLaughlin, V. M. Kaspi, L. Kasian, J. S. Deneva, B. Reid, S. Chatterjee, J. L. Han, D. C. Backer, I. H. Stairs, A. A. Deshpande, and C.-A. Faucher-Giguère Arecibo Pulsar Survey Using ALFA. I. Survey Strategy and First Discoveries
2006AnP...518...34K 01/2006
Kramer, M.; Stairs, I. H.; Manchester, R. N.; McLaughlin, M. A.; Lyne, A. G.; Ferdman, R. D.; Burgay, M.; Lorimer, D. R.; Possenti, A.; D'Amico, N.; Sarkissian, J.; Joshi, B. C.; Freire, P. C. C.; Camilo, F. Strong-field tests of gravity with the double pulsar

2005
2005MNRAS.363..929C 11/2005
D. J. Champion, D. R. Lorimer, M. A. McLaughlin, K. M. Xilouris, Z. Arzoumanian, P. C. C. Freire, A. N. Lommen, J. M. Cordes and F. Camilo Arecibo timing and single-pulse observations of 17 pulsars
2005ApJ...632.1060S 10/2005
I. H. Stairs, A. J. Faulkner, A. G. Lyne, M. Kramer, D. R. Lorimer, M. A. McLaughlin, R. N. Manchester, G. B. Hobbs, F. Camilo, A. Possenti, M. Burgay, N. D'Amico, P. C. Freire, P. C. Gregory Discovery of Three Wide-Orbit Binary Pulsars: Implications for Binary Evolution and Equivalence Principles
2005ApJ...625..796H 06/2005
C. O. Heinke, J. E. Grindlay, P. D. Edmonds, H. N. Cohn, P. M. Lugger, F. Camilo, S. Bogdanov, P. C. Freire A Deep Chandra Survey of the Globular Cluster 47 Tucanae: Catalog of Point Sources
2005ApJ...624L.113B 05/2005
M. Burgay, A. Possenti, R. N. Manchester, M. Kramer, M. A. McLaughlin, D. R. Lorimer, I. H. Stairs, B. C. Joshi, A. G. Lyne, F. Camilo, N. D'Amico, P. C. C. Freire, J. M. Sarkissian, A. W. Hotan, G. B. Hobbs Long-term variations in the pulse emission from PSR J0737−3039B
2005ApJ...621..959F 03/2005
Paulo C. C. Freire, Jason W. T. Hessels, David J. Nice, Scott M. Ransom, Duncan R. Lorimer, Ingrid H. Stairs The Millisecond Pulsars in NGC 6760
2005ApJ...621L..49M 03/2005
R. N. Manchester, M. Kramer, A. Possenti, A. G. Lyne, M. Burgay, I. H. Stairs, A. W. Hotan, M. A. McLaughlin, D. R. Lorimer, G. B. Hobbs, J. M. Sarkissian, N. D'Amico, F. Camilo, B. C. Joshi, P. C. C. Freire The mean pulse profile of PSR J0737−3039A
2005BASI...33..345J 00/2005
Joshi, B. C.; McLaughlin, M. A.; Lyne, A. G.; Kramer, M.; Lorimer, D. R.; Manchester, R. N.; Camilo, F.; Burgay, M.; Possenti, A.; D'Amico, N.; Freire, P. C. C. Multifrequency observations of double pulsar J0737−3039 using GMRT.
2005Sci...307..892R 02/2005
Scott M. Ransom, Jason W. T. Hessels, Ingrid H. Stairs, Paulo C. C. Freire, Fernando Camilo, Victoria M. Kaspi, David L. Kaplan Twenty-One Millisecond Pulsars in Terzan 5 Using the Green Bank Telescope

2004
2004ApJ..616L..131M 12/2004
M. A. McLaughlin, A. G. Lyne, D. R. Lorimer, A. Possenti, R. N. Manchester, F. Camilo, I. H. Stairs, M. Kramer, M. Burgay, N. D'Amico, P. C. C. Freire, B. C. Joshi, N. D. R. Bhat The Double Pulsar System J0737−3039: Modulation of A by B at eclipse
2004ApJ..613L..57M 09/2004
M. A. McLaughlin, M. Kramer, A. G. Lyne, D. R. Lorimer, I. H. Stairs, A. Possenti, R. N. Manchester, P. C. C. Freire, B. C. Joshi, M. Burgay, F. Camilo, N. D'Amico The Double Pulsar System J0737−3039: Modulation of the radio emission from B by radiation from A
2004BASI...32..191J 09/2004
Joshi, B. C.; McLaughlin, M. A.; Lyne, A. G.; Kramer, M.; Lorimer, D. R.; Manchester, R. N.; Camilo, F.; Burgay, M.; Possenti, A.; Amico, N. D.; Freire, P. C. C. Double pulsar system J0737−3039 and its low-frequency observations with GMRT.
2004ApJ...612..389H 09/2004
J. W. T. Hessels, M. S. E. Roberts, S. M. Ransom, V. M. Kaspi, R. W. Romani, C.-Y. Ng, P. C. C. Freire, B. M. Gaensler Observations of PSR J2021+3651 and its X-ray Pulsar Wind Nebula G75.2+01
2004ApJ...606L..53F 03/2004
P. C. C. Freire, Yashwant Gupta, Scott M. Ransom and C. H. Ishwara-Chandra GMRT Discovery of A Millisecond Pulsar in a Very Eccentric Binary System
2004AdSpR..33..577R * 02/2004
Mallory S.E. Roberts, Jason W.T. Hessels, Scott M. Ransom, Victoria M. Kaspi, Paulo C.C. Freire, Fronefield Crawford, Duncan R. Lorimer PSR J2021+3651: A New Gamma-Ray Pulsar Candidate
2004Sci...303.1153L 01/2004
A. G. Lyne, M. Burgay, M. Kramer, A. Possenti, R. N. Manchester, F. Camilo, M. A. McLaughlin, D. R. Lorimer, N. D'Amico, B. C. Joshi, J. Reynolds, P. C. C. Freire A Double-Pulsar System: A Rare Laboratory for Relativistic Gravity and Plasma Physics

2003
2003ApJ...594..943N 09/2003
Navarro, J.; Anderson, S. B.; Freire, P. C. The Arecibo 430 MHz Intermediate Galactic Latitude Survey: Discovery of Nine Radio Pulsars
2003MNRAS.340.1359F 04/2003
Freire, P. C.; Camilo, F.; Kramer, M.; Lorimer, D. R.; Lyne, A. G.; Manchester, R. N.; D'Amico, N. Further results from the timing of the millisecond pulsars in 47 Tucanae

2002
2002ApJ...577L..19R 09/2002
Roberts, Mallory S. E.; Hessels, Jason W. T.; Ransom, Scott M.; Kaspi, Victoria M.; Freire, Paulo C. C.; Crawford, Fronefield; Lorimer, Duncan R. PSR J2021+3651: A Young Radio Pulsar Coincident with an Unidentified EGRET γ-Ray Source

2001
2001MNRAS.326..901F 09/2001
Freire, P. C.; Camilo, F.; Lorimer, D. R.; Lyne, A. G.; Manchester, R. N.; D'Amico, N. Timing the millisecond pulsars in 47 Tucanae
2001ApJ...557L.105F 08/2001
Freire, P. C.; Kramer, M.; Lyne, A. G.; Camilo, F.; Manchester, R. N.; D'Amico, N. Detection of Ionized Gas in the Globular Cluster 47 Tucanae
NOTE: see commentary of this result published in Science.
2001MNRAS.322..885F 04/2001
Freire, P. C.; Kramer, M.; Lyne, A. G. Determination of the orbital parameters of binary pulsars
NOTE: see brief description of method and erratum.

2000
2000ApJ...535..975C 06/2000
Camilo, F.; Lorimer, D. R.; Freire, P.; Lyne, A. G.; Manchester, R. N. Observations of 20 Millisecond Pulsars in 47 Tucanae at 20 Centimeters
2000Ap&SS.272..275F * 2000
Freire, P. C.; da Costa, A. A. Centrifugal Forces and Optical Geometry in Neutron Stars

1999
1999MNRAS.304..235F 04/1999
Freire, P. C.; da Costa, A. A. Behaviour of centrifugal forces in neutron stars