T. J. Johnson

Pulsed Gamma Rays from the Original Millisecond and Black Widow Pulsars: A Case for Caustic Radio Emission?

We report the detection of pulsed gamma-ray emission from the fast millisecond pulsars (MSPs) B1937+21 (also known as J1939+2134) and B1957+20 (J1959+2048) using 18 months of survey data recorded by the emph{Fermi} Large Area Telescope (LAT) and timing solutions based on radio observations conducted at the Westerbork and Nancay radio telescopes. In addition, we analyzed archival emph{RXTE} and emph{XMM-Newton} X-ray data for the two MSPs, confirming the X-ray emission properties of PSR B1937+21 and finding evidence (

Discovery of Psr J1227-4853: A Transition from a Low-mass X-Ray Binary to a Redback Millisecond Pulsar

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Discovery of Gamma-ray Pulsations from the Transitional Redback PSR J1227-4853

) for pulsed emission from PSR B1957+20 for the first time. In both cases the gamma-ray emission profile is characterized by two peaks separated by half a rotation and are in close alignment with components observed in radio and X-rays. These two pulsars join PSRs J0034-0534 and J2214+3000 to form an emerging class of gamma-ray MSPs with phase-aligned peaks in different energy bands. The modeling of the radio and gamma-ray emission profiles suggests co-located emission regions in the outer magnetosphere.

Multiwavelength monitoring and X-ray brightening of Be X-ray binary PSR J2032+4127/MT91 213 on its approach to periastron

XSS J12270-4859 is an X-ray binary associated with the Fermi LAT gamma-ray source 1FGL J1227.9-4852. In 2012 December, this source underwent a transition where the X-ray and optical luminosity dropped and the spectral signatures of an accretion disc disappeared. We report the discovery of a 1.69 millisecond pulsar (MSP), PSR J1227-4853, at a dispersion measure of 43.4 pc cm

The Braking Index of a Radio-quiet Gamma-ray Pulsar

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A comprehensive study of high-energy gamma-ray and radio emission from Cyg X-3

associated with this source, using the GMRT at 607 MHz. This demonstrates that, post-transition, the system hosts an active radio MSP. This is the third system after PSR J1023+0038 and PSR J1824-2452I showing evidence of state switching between radio MSP and low-mass X-ray binary (LMXB) states. We report timing observations of PSR J1227-4853 with the GMRT and Parkes, which give a precise determination of the rotational and orbital parameters of the system. The companion mass measurement of 0.17 to 0.46 M

The Einstein@Home Gamma-ray Pulsar Survey. II. Source Selection, Spectral Analysis, and Multiwavelength Follow-up

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High-energy Variability of PSR J1311-3430

suggests that this is a redback system. PSR J1227-4853 is eclipsed for about 40% of its orbit at 607 MHz; with additional short-duration eclipses at all orbital phases. We also find that the pulsar is very energetic, with a spin-down luminosity of ~ 10

Modeling the pulse profiles of millisecond pulsars in the second LAT catalog of γ-ray pulsars

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A Luminous and Highly Variable Gamma-Ray Flare Following the 2017 Periastron of PSR B1259–63/LS 2883

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