FERMI LARGE AREA TELESCOPE OBSERVATIONS OF PSR J1836+5925 (original) (raw)
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PSR J1838–0537: Discovery of a Young, Energetic Gamma-Ray Pulsar
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, 2009
Radio pulsar PSR J1028-5819 was recently discovered in a high-frequency search (at 3.1 GHz) in the error circle of the EGRET source 3EG J1027-5817. The spin-down power of this young pulsar is great enough to make it very likely the counterpart for the EGRET source. We report here the discovery of γ-ray pulsations from PSR J1028-5819 in early observations by the Large Area Telescope (LAT) on the Fermi Gamma-Ray Space Telescope. The γ-ray light curve shows two sharp peaks having phase separation of 0.460 ± 0.004, trailing the very narrow radio pulse by 0.200 ± 0.003 in phase, very similar to that of other known γ-ray pulsars. The measured γ-ray flux gives an efficiency for the pulsar of ∼ 10 − 20% (for outer magnetosphere beam models). No evidence of a surrounding pulsar wind nebula is seen in the current Fermi data but limits on associated emission are weak because the source lies in a crowded region with high background emission. However, the improved angular resolution afforded by the LAT enables the disentanglement of the previous COS-B and EGRET source detections into at least two distinct sources, one of which is now identified as PSR J1028-5819.
Studies of high-energy pulsars: The special case of PSR J1849-0001
Nuclear and Particle Physics Proceedings, 2018
We present the results from the data analysis of the XMM-Newton observation (53.6 ks) on PSR J1849-0001. We studied in detail the X-ray emission of this pulsar and we found extended emission (up to ≈ 100 arcsec) from the Pulsar Wind Nebula (PWN), confirming that this is a case of a Pulsar/PWN system and strengthening the evidence that X-ray, hard X-ray and TeV gamma-ray sources are manifestations of the same system. Another important result of our study is the clear evidence that the X-ray PWN of PSR J1849-0001 is asymmetric.
PSR J2021+3651: A Young Radio Pulsar Coincident with an Unidentified EGRET γ-Ray Source
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.
PSR J2021+3651: a new γ-ray pulsar candidate
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.
The Astrophysical Journal, 2001
We report the discovery of a young and energetic pulsar in the Parkes multibeam survey of the Galactic plane. PSR J1016−5857 has a rotation period of 107 ms and period derivative of 8.0 × 10 −14 , implying a characteristic age of 21 kyr and spin-down luminosity of 2.6 × 10 36 erg s −1 . The pulsar is located just outside, and possibly interacting with, the shell supernova remnant G284.3−1.8. Archival X-ray data show a source near the pulsar position which is consistent with emission from a pulsar wind nebula. The pulsar is also located inside the error box of the unidentified EGRET source 3EG J1013−5915, for which it represents a plausible counterpart.
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.
RADIO DETECTION OF LAT PSRs J1741-2054 AND J2032+4127: NO LONGER JUST GAMMA-RAY PULSARS
The Astrophysical Journal, 2009
Sixteen pulsars have been discovered so far in blind searches of photons collected with the Large Area Telescope on the Fermi Gamma-ray Space Telescope. We here report the discovery of radio pulsations from two of them. PSR J1741-2054, with period P = 413 ms, was detected in archival Parkes telescope data and subsequently has been detected at the Green Bank Telescope (GBT). Its received flux varies greatly due to interstellar scintillation and it has a very small dispersion measure of DM = 4.7 pc cm −3 , implying a distance of ≈ 0.4 kpc and possibly the smallest luminosity of any known radio pulsar. At this distance, for isotropic emission, its gamma-ray luminosity above 0.1 GeV corresponds to 25% of the spin-down luminosity ofĖ = 9.4 × 10 33 erg s −1. The gamma-ray profile occupies 1/3 of pulse phase and has three closely-spaced peaks with the first peak lagging the radio pulse by δ = 0.29 P. We have also identified a soft Swift source that is the likely X-ray counterpart. In many respects PSR J1741-2054 resembles the Geminga pulsar. The second source, PSR J2032+4127, was detected at the GBT. It has P = 143 ms, and its DM = 115 pc cm −3 suggests a distance of ≈ 3.6 kpc, but we consider it likely that it is located within the Cyg OB2 stellar association at half that distance. The radio emission is nearly 100% linearly polarized, and the main radio peak precedes by δ = 0.15 P the first of two narrow gamma-ray peaks that are separated by ∆ = 0.50 P. The second peak has a harder spectrum than the first one, following a trend observed in young gamma-ray pulsars. Faint, diffuse X-ray emission in a Chandra image is possibly its pulsar wind nebula. PSR J2032+4127 likely accounts for the EGRET source 3EG J2033+4118, while its pulsar wind is responsible for the formerly unidentified HEGRA source TeV J2032+4130. PSR J2032+4127 is coincident in projection with MT91 213, a Be star in Cyg OB2, although apparently not a binary companion of it.
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.
X‐Ray Observations of the High Magnetic Field Radio Pulsar PSR J1814−1744
The Astrophysical Journal, 2000
PSR J1814−1744 is a 4 s radio pulsar with surface dipole magnetic field strength 5.5× 10 13 G, inferred assuming simple magnetic dipole braking. This pulsar's spin parameters are very similar to those of anomalous X-ray pulsars (AXPs), suggesting that this may be a transition object between the radio pulsar and AXP population, if AXPs are isolated, high magnetic field neutron stars as has recently been hypothesized. We present archival X-ray observations of PSR J1814−1744 made with ROSAT and ASCA. X-ray emission is not detected from the position of the radio pulsar. The derived upper flux limit implies an X-ray luminosity significantly smaller than those of all known AXPs. This conclusion is insensitive to the possibility that X-ray emission from PSR J1814−1744 is beamed or that it undergoes modest variability. When interpreted in the context of the magnetar mechanism, these results argue that X-ray emission from AXPs must depend on more than merely the inferred surface magnetic field strength. This suggests distinct evolutionary paths for radio pulsars and AXP, despite their proximity in period-period derivative phase space.