Fermi large area telescope observations of psr j1836+ 5925

The Astrophysical Journal, 2012

We report the discovery of PSR J1838−0537, a gamma-ray pulsar found through a blind search of data from the Fermi Large Area Telescope (LAT). The pulsar has a spin frequency of 6.9 Hz and a frequency derivative of −2.2 × 10 −11 Hz s −1 , implying a young characteristic age of 4970 years and a large spin-down power of 5.9 × 10 36 erg s −1. Follow-up observations with radio telescopes detected no pulsations, thus PSR J1838−0537 appears radio-quiet as viewed from Earth. In September 2009 the pulsar suffered the largest glitch so far seen in any gamma-ray-only pulsar, causing a relative increase in spin frequency of about 5.5 × 10 −6. After the glitch, during a putative recovery period, the timing analysis is complicated by the sparsity of the LAT photon data, the weakness of the pulsations, and the reduction in average exposure from a coincidental, contemporaneous change in the LAT's sky-survey observing pattern. The pulsar's sky position is coincident with the spatially extended TeV source HESS J1841−055 detected by the High Energy Stereoscopic System (H.E.S.S.). The inferred energetics suggest that HESS J1841−055 contains a pulsar wind nebula powered by the pulsar.

The Astrophysical Journal, 2010

The Fermi Large Area Telescope (LAT) data have confirmed the pulsed emission from all six high-confidence gamma-ray pulsars previously known from the EGRET observations. We report results obtained from the analysis of 13 months of LAT data for three of these pulsars (PSR J1057−5226, PSR J1709−4429, and PSR J1952+3252) each of which had some unique feature among the EGRET pulsars. The excellent sensitivity of LAT allows more detailed analysis of the evolution of the pulse profile with energy and also of the variation of the spectral shape with phase. We measure the cutoff energy of the pulsed emission from these pulsars for the first time and provide a more complete picture of the emission mechanism. The results confirm some, but not all, of the features seen in the EGRET data.

Astrophysical Journal, 2002

We report on a deep search for radio pulsations toward five unidentified ASCA X-ray sources coincident with EGRET g-ray sources. This search has led to the discovery of a young and energetic pulsar using data obtained with the new Wideband Arecibo Pulsar Processor. PSR J2021ϩ3651 is likely associated with the X-ray source AX J2021.1ϩ3651, which in turn is likely associated with the COS B high-energy g-ray source 2CG 075ϩ00, also known as GeV J2020ϩ3658 or 3EG J2021ϩ3716. PSR J2021ϩ3651 has a rotation period of ms P ∼ 104 and , implying a characteristic age of kyr and a spin-down luminosity of Ϫ14Ṗ ∼ 9.6 # 10 t ∼ 17 E ∼ 3.4 # c 10 36 ergs s Ϫ1 . The dispersion measure D pc cm Ϫ3 is by far the highest of any observed pulsar in the Galactic M ∼ 371 longitude range . This DM suggests a distance kpc and a high g-ray efficiency of ∼15%, but 55Њ ! l ! 80Њ d տ 10 the true distance may be closer if there is a significant contribution to the DM from excess gas in the Cygnus region. The implied luminosity of the associated X-ray source suggests the X-ray emission is dominated by a pulsar wind nebula unresolved by ASCA.

Advances in Space Research, 2004

The COS B high energy γ-ray source 2CG 075+00, also known as GeV J2020+3658 or 3EG J2021+3716, has avoided identification with a low energy counterpart for over twenty years. We present a likely identification with the discovery and subsequent timing of a young and energetic pulsar, PSR J2021+3651, with the Wideband Arecibo Pulsar Processor at the Arecibo Observatory. PSR J2021+3651 has a rotation period P ∼ 104 ms andṖ ∼ 9.6 × 10 −14 , implying a characteristic age τ c ∼ 17 kyr and a spin-down luminosityĖ ∼ 3.4 × 10 36 erg s −1. The pulsar is also coincident with the ASCA source AX J2021.1+3651. The implied luminosity of the associated X-ray source suggests the Xray emission is dominated by a pulsar wind nebula unresolved by ASCA. The pulsar's unexpectedly high dispersion measure (DM ∼ 371 pc cm −3) and the d ≥ 10 kpc DM distance pose a new question: is PSR J2021+3651 an extremely efficient γ-ray pulsar at the edge of the Galaxy? This is a question for AGILE and GLAST to answer.

Astrophysical Journal, 2001

We report the detection of radio and X-ray pulsations at a period of 51.6 ms from the X-ray source RX/AX J2229.0+6114 in the error box of the EGRET source 3EG J2227+6122. An ephemeris derived from a single ASCA observation and multiple epochs at 1412 MHz from Jodrell Bank indicates steady spin-down with P-dot = 7.83 x 10^(-14) s/s. From the measured P and P-dot we derive spin-down power E-dot = 2.2 x 10^(37) erg/s, magnetic field B = 2.0 x 10^(12) G, and characteristic age P/2P-dot = 10,460 yr. An image from the Chandra X-ray Observatory reveals a point source surrounded by centrally peaked diffuse emission that is contained within an incomplete radio shell. We assign the name G106.6+2.9 to this new supernova remnant, which is evidently a pulsar wind nebula. For a distance of 3 kpc estimated from X-ray absorption, the ratio of X-ray luminosity to spin-down power is ~8 x 10^(-5), smaller than that of most pulsars, but similar to the Vela pulsar. If PSR J2229+6114 is the counterpart of 3EG J2227+6122 then its efficiency of gamma-ray production, if isotropic, is 0.016 (d/3 kpc)^2. It obeys an established trend of gamma-ray efficiency among known gamma-ray pulsars which, in combination with the demonstrated absence of any other plausible counterpart for 3EG J2227+6122, makes the identification compelling. If confirmed, this identification bolsters the pulsar model for unidentified Galactic EGRET sources.