| 1. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 2. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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| 3. |
- Abdo, A. A., et al.
(författare)
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The second Fermi large area telescope catalog of gamma-ray pulsars
- 2013
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 208:2, s. 17-
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Tidskriftsartikel (refereegranskat)abstract
- This catalog summarizes 117 high-confidence ≥0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions.
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| 4. |
- Weltevrede, P., et al.
(författare)
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Gamma-ray and radio properties of six pulsars detected by the Fermi large area telescope
- 2010
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 708:2, s. 1426-1441
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Tidskriftsartikel (refereegranskat)abstract
- We report the detection of pulsed gamma-rays for PSRs J0631+1036, J0659+1414, J0742-2822, J1420-6048, J1509-5850, and J1718-3825 using the Large Area Telescope on board the Fermi Gamma-ray Space Telescope (formerly known as GLAST). Although these six pulsars are diverse in terms of their spin parameters, they share an important feature: their gamma-ray light curves are (at least given the current count statistics) single peaked. For two pulsars, there are hints for a double-peaked structure in the light curves. The shapes of the observed light curves of this group of pulsars are discussed in the light of models for which the emission originates from high up in the magnetosphere. The observed phases of the gamma-ray light curves are, in general, consistent with those predicted by high-altitude models, although we speculate that the gamma-ray emission of PSR J0659+1414, possibly featuring the softest spectrum of all Fermi pulsars coupled with a very low efficiency, arises from relatively low down in the magnetosphere. High-quality radio polarization data are available showing that all but one have a high degree of linear polarization. This allows us to place some constraints on the viewing geometry and aids the comparison of the gamma-ray light curves with high-energy beam models.
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| 5. |
- Abdo, A. A., et al.
(författare)
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DETECTION OF THE ENERGETIC PULSAR PSR B1509-58 AND ITS PULSAR WIND NEBULA IN MSH 15-52 USING THE FERMI-LARGE AREA TELESCOPE
- 2010
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 714:1, s. 927-936
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Tidskriftsartikel (refereegranskat)abstract
- We report the detection of high-energy gamma-ray emission from the young and energetic pulsar PSR B1509-58 and its pulsar wind nebula (PWN) in the composite supernova remnant G320.4-1.2 (aka MSH 15-52). Using 1 yr of survey data with the Fermi-Large Area Telescope (LAT), we detected pulsations from PSR B1509-58 up to 1 GeV and extended gamma-ray emission above 1 GeV spatially coincident with the PWN. The pulsar light curve presents two peaks offset from the radio peak by phases 0.96 +/- 0.01 and 0.33 +/- 0.02. New constraining upper limits on the pulsar emission are derived below 1 GeV and confirm a severe spectral break at a few tens of MeV. The nebular spectrum in the 1-100 GeV energy range is well described by a power law with a spectral index of (1.57 +/- 0.17 +/- 0.13) and a flux above 1 GeV of (2.91 +/- 0.79 +/- 1.35) x 10(-9) cm(-2) s(-1). The first errors represent the statistical errors on the fit parameters, while the second ones are the systematic uncertainties. The LAT spectrum of the nebula connects nicely with Cherenkov observations, and indicates a spectral break between GeV and TeV energies.
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| 6. |
- Abdo, A. A., et al.
(författare)
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DISCOVERY OF PULSATIONS FROM THE PULSAR J0205+6449 IN SNR 3C 58 WITH THE FERMI GAMMA-RAY SPACE TELESCOPE
- 2009
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Ingår i: Astrophysical Journal Letters. - 2041-8205 .- 0004-637X .- 1538-4357. ; 699:2, s. L102-L107
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery of gamma-ray pulsations (>= 0.1 GeV) from the young radio and X-ray pulsar PSR J0205 + 6449 located in the Galactic supernova remnant 3C 58. Data in the gamma-ray band were acquired by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope (formerly GLAST), while the radio rotational ephemeris used to fold gamma-rays was obtained using both the Green Bank Telescope and the Lovell telescope at Jodrell Bank. The light curve consists of two peaks separated by 0.49 +/- 0.01 +/- 0.01 cycles which are aligned with the X-ray peaks. The first gamma-ray peak trails the radio pulse by 0.08 +/- 0.01 +/- 0.01, while its amplitude decreases with increasing energy as for the other gamma-ray pulsars. Spectral analysis of the pulsed gamma-ray emission suggests a simple power law of index -2.1 +/- 0.1 +/- 0.2 with an exponential cutoff at 3.0(-0.7)(+1.1) +/- 0.4 GeV. The first uncertainty is statistical and the second is systematic. The integral gamma-ray photon flux above 0.1 GeV is (13.7 +/- 1.4 +/- 3.0) x 10(-8) cm(-2) s(-1), which implies for a distance of 3.2 kpc and assuming a broad fan-like beam a luminosity of 8.3 x 10(34) erg s(-1) and an efficiency eta of 0.3%. Finally, we report a 95% upper limit on the flux of 1.7 x 10(-8) cm(-2) s(-1) for off-pulse emission from the object.
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| 7. |
- Ackermann, M., et al.
(författare)
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Fermi-LAT search for pulsar wind nebulae around gamma-ray pulsars
- 2011
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 726:1, s. 35-
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Tidskriftsartikel (refereegranskat)abstract
- The high sensitivity of the Fermi-LAT (Large Area Telescope) offers the first opportunity to study faint and extended GeV sources such as pulsar wind nebulae (PWNe). After one year of observation the LAT detected and identified three PWNe: the Crab Nebula, Vela-X, and the PWN inside MSH 15-52. In the meantime, the list of LAT detected pulsars increased steadily. These pulsars are characterized by high energy loss rates ((E) over dot) from similar to 3 x 10(33) erg s(-1) to 5 x 10(38) erg s(-1) and are therefore likely to power a PWN. This paper summarizes the search for PWNe in the off-pulse windows of 54 LAT-detected pulsars using 16 months of survey observations. Ten sources show significant emission, seven of these likely being of magnetospheric origin. The detection of significant emission in the off-pulse interval offers new constraints on the gamma-ray emitting regions in pulsar magnetospheres. The three other sources with significant emission are the Crab Nebula, Vela-X, and a new PWN candidate associated with the LAT pulsar PSR J1023-5746, coincident with the TeV source HESS J1023-575. We further explore the association between the HESS and the Fermi source by modeling its spectral energy distribution. Flux upper limits derived for the 44 remaining sources are used to provide new constraints on famous PWNe that have been detected at keV and/or TeV energies.
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| 8. |
- Abdo, A. A., et al.
(författare)
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DISCOVERY OF HIGH-ENERGY GAMMA-RAY EMISSION FROM THE BINARY SYSTEM PSR B1259-63/LS 2883 AROUND PERIASTRON WITH FERMI
- 2011
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Ingår i: Astrophysical Journal Letters. - 2041-8205. ; 736:1, s. L11-
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Tidskriftsartikel (refereegranskat)abstract
- We report on the discovery of >= 100 MeV gamma-rays from the binary system PSR B1259-63/LS 2883 using the Large Area Telescope (LAT) on board Fermi. The system comprises a radio pulsar in orbit around a Be star. We report on LAT observations from near apastron to similar to 128 days after the time of periastron, t(p), on 2010 December 15. No gamma-ray emission was detected from this source when it was far from periastron. Faint gamma-ray emission appeared as the pulsar approached periastron. At similar to t(p) + 30 days, the >= 100 MeV gamma-ray flux increased over a period of a few days to a peak flux 20-30 times that seen during the pre-periastron period, but with a softer spectrum. For the following month, it was seen to be variable on daily timescales, but remained at similar to(1-4) x 10(-6) cm(-2) s(-1) before starting to fade at similar to t(p) + 57 days. The total gamma-ray luminosity observed during this period is comparable to the spin-down power of the pulsar. Simultaneous radio and X-ray observations of the source showed no corresponding dramatic changes in radio and X-ray flux between the pre-periastron and post-periastron flares. We discuss possible explanations for the observed gamma-ray-only flaring of the source.
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| 9. |
- Abdo, A. A., et al.
(författare)
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DISCOVERY OF PULSED gamma-RAYS FROM THE YOUNG RADIO PULSAR PSR J1028-5819 WITH THE FERMI LARGE AREA TELESCOPE
- 2009
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Ingår i: Astrophysical Journal Letters. - 2041-8205. ; 695:1, s. L72-L77
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Tidskriftsartikel (refereegranskat)abstract
- Radio pulsar PSR J1028-5819 was recently discovered in a high-frequency search (at 3.1 GHz) in the error circle of the Energetic Gamma-Ray Experiment Telescope (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 gamma-ray pulsations from PSR J1028-5819 in early observations by the Large Area Telescope (LAT) on the Fermi Gamma-Ray Space Telescope. The gamma-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 gamma-ray pulsars. The measured gamma-ray flux gives an efficiency for the pulsar of similar to 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.
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| 10. |
- Ardo, A. A., et al.
(författare)
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FERMI LARGE AREA TELESCOPE OBSERVATIONS OF GAMMA-RAY PULSARS PSR J1057-5226, J1709-4429, AND J1952+3252
- 2010
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 720:1, s. 26-40
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Tidskriftsartikel (refereegranskat)abstract
- 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 11952+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.
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| 11. |
- Freire, P. C. C., et al.
(författare)
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Fermi Detection of a Luminous gamma-Ray Pulsar in a Globular Cluster
- 2011
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 334:6059, s. 1107-1110
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Tidskriftsartikel (refereegranskat)abstract
- We report on the Fermi Large Area Telescope's detection of gamma-ray (>100 mega-electron volts) pulsations from pulsar J1823-3021A in the globular cluster NGC 6624 with high significance (similar to 7 sigma). Its gamma-ray luminosity, L(gamma) = (8.4 +/- 1.6) x 10(34) ergs per second, is the highest observed for any millisecond pulsar (MSP) to date, and it accounts for most of the cluster emission. The nondetection of the cluster in the off-pulse phase implies that it contains <32 gamma-ray MSPs, not similar to 100 as previously estimated. The gamma-ray luminosity indicates that the unusually large rate of change of its period is caused by its intrinsic spin-down. This implies that J1823-3021A has the largest magnetic field and is the youngest MSP ever detected and that such anomalous objects might be forming at rates comparable to those of the more normal MSPs.
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| 12. |
- Ajello, M., et al.
(författare)
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A gamma-ray pulsar timing array constrains the nanohertz gravitational wave background
- 2022
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 376:6592, s. 521-523
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Tidskriftsartikel (refereegranskat)abstract
- After large galaxies merge, their central supermassive black holes are expected to form binary systems. Their orbital motion should generate a gravitational wave background (GWB) at nanohertz frequencies. Searches for this background use pulsar timing arrays, which perform long-term monitoring of millisecond pulsars at radio wavelengths. We used 12.5 years of Fermi Large Area Telescope data to form a gamma-ray pulsar timing array. Results from 35 bright gamma-ray pulsars place a 95% credible limit on the GWB characteristic strain of 1.0 x 10(-14) at a frequency of 1 year(-1). The sensitivity is expected to scale with t(obs), the observing time span, as t(obs)(-13/6). This direct measurement provides an independent probe of the GWB while offering a check on radio noise models.
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| 13. |
- Price, Patricia E., et al.
(författare)
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Dressing-related pain in patients with chronic wounds : an international patient perspective
- 2008
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Ingår i: International Wound Journal. - 1742-4801 .- 1742-481X. ; 5:2, s. 159-171
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Tidskriftsartikel (refereegranskat)abstract
- This cross-sectional international survey assessed patients' perceptions of their wound pain. A total of 2018 patients (57% female) from 15 different countries with a mean age of 68.6 years (SD = 15.4) participated. The wounds were categorised into ten different types with a mean wound duration of 19.6 months (SD = 51.8). For 2018 patients, 3361 dressings/compression systems were being used, with antimicrobials being reported most frequently (n= 605). Frequency of wound-related pain was reported as 32.2%, 'never' or 'rarely', 31.1%, 'quite often' and 36.6%, 'most' or 'all of the time', with venous and arterial ulcers associated with more frequent pain (P= 0.002). All patients reported that 'the wound itself' was the most painful location (n= 1840). When asked if they experienced dressing-related pain, 286 (14.7%) replied 'most of the time' and 334 (17.2%) reported pain 'all of the time'; venous, mixed and arterial ulcers were associated with more frequent pain at dressing change (P < 0.001). Eight hundred and twelve (40.2%) patients reported that it took <1 hour for the pain to subside after a dressing change, for 449 (22.2%) it took 1-2 hours, for 192 (9.5%) it took 3-5 hours and for 154 (7.6%) patients it took more than 5 hours. Pain intensity was measured using a visual analogue scale (VAS) (0-100) giving a mean score of 44.5 (SD = 30.5, n= 1981). Of the 1141 who reported that they generally took pain relief, 21% indicated that they did not feel it was effective. Patients were asked to rate six symptoms associated with living with a chronic wound; 'pain' was given the highest mean score of 3.1 (n= 1898). In terms of different types of daily activities, 'overdoing things' was associated with the highest mean score (mean = 2.6, n= 1916). During the stages of the dressing change procedure; 'touching/handling the wound' was given the highest mean score of 2.9, followed by cleansing and dressing removal (n= 1944). One thousand four hundred and eighty-five (80.15%) patients responded that they liked to be actively involved in their dressing changes, 1141 (58.15%) responded that they were concerned about the long-term side-effects of medication, 790 (40.3%) of patient indicated that the pain at dressing change was the worst part of living with a wound. This study adds substantially to our knowledge of how patients experience wound pain and gives us the opportunity to explore cultural differences in more detail.
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| 14. |
- Price, Patricia E., et al.
(författare)
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Dressing-related pain in patients with chronic wounds : an international patient perspective
- 2008
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Ingår i: International Wound Journal. - : Wiley-Blackwell Publishing Ltd. - 1742-4801 .- 1742-481X. ; 5:2, s. 159-171
-
Tidskriftsartikel (refereegranskat)abstract
- This cross-sectional international survey assessed patients' perceptions of their wound pain. A total of 2018 patients (57% female) from 15 different countries with a mean age of 68.6 years (SD = 15.4) participated. The wounds were categorised into ten different types with a mean wound duration of 19.6 months (SD = 51.8). For 2018 patients, 3361 dressings/compression systems were being used, with antimicrobials being reported most frequently (n= 605). Frequency of wound-related pain was reported as 32.2%, 'never' or 'rarely', 31.1%, 'quite often' and 36.6%, 'most' or 'all of the time', with venous and arterial ulcers associated with more frequent pain (P= 0.002). All patients reported that 'the wound itself' was the most painful location (n= 1840). When asked if they experienced dressing-related pain, 286 (14.7%) replied 'most of the time' and 334 (17.2%) reported pain 'all of the time'; venous, mixed and arterial ulcers were associated with more frequent pain at dressing change (P < 0.001). Eight hundred andtwelve (40.2%) patients reported that it took <1 hour for the pain to subside after a dressing change, for 449 (22.2%) it took 1-2 hours, for 192 (9.5%) it took 3-5 hours and for 154 (7.6%) patients it took more than 5 hours. Pain intensity was measured using a visual analogue scale (VAS) (0-100) giving a mean score of 44.5 (SD = 30.5, n= 1981). Of the 1141 who reported that they generally took pain relief, 21% indicated that they did not feel it was effective. Patients were asked to rate six symptoms associated with living with a chronic wound; 'pain' was given the highest mean score of 3.1 (n= 1898). In terms of different types of daily activities, 'overdoing things' was associated with the highest mean score (mean = 2.6, n= 1916). During the stages of the dressing change procedure; 'touching/handling the wound' was given the highest mean score of 2.9, followed by cleansing and dressing removal (n= 1944). One thousand four hundred and eighty-five (80.15%) patients responded that they liked to be actively involved in their dressing changes, 1141 (58.15%) responded that they were concerned about the long-term side-effects of medication, 790 (40.3%) of patient indicated that the pain at dressing change was the worst part of living with a wound. This study adds substantially to our knowledge of how patients experience wound pain and gives us the opportunity to explore cultural differences in more detail.
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| 15. |
- Younes, George, et al.
(författare)
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X-Ray Burst and Persistent Emission Properties of the Magnetar SGR 1830-0645 in Outburst
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 924:2
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Tidskriftsartikel (refereegranskat)abstract
- We report on NICER X-ray monitoring of the magnetar SGR 1830-0645 covering 223 days following its 2020 October outburst, as well as Chandra and radio observations. We present the most accurate spin ephemerides of the source so far: nu = 0.096008680(2) Hz, = -6.2(1) x 10(-14) Hz s(-1), and significant second and third frequency derivative terms indicative of nonnegligible timing noise. The phase-averaged 0.8-7 keV spectrum is well fit with a double-blackbody (BB) model throughout the campaign. The BB temperatures remain constant at 0.46 and 1.2 keV. The areas and flux of each component decreased by a factor of 6, initially through a steep decay trend lasting about 46 days, followed by a shallow long-term one. The pulse shape in the same energy range is initially complex, exhibiting three distinct peaks, yet with clear continuous evolution throughout the outburst toward a simpler, single-pulse shape. The rms pulsed fraction is high and increases from about 40% to 50%. We find no dependence of pulse shape or fraction on energy. These results suggest that multiple hot spots, possibly possessing temperature gradients, emerged at outburst onset and shrank as the outburst decayed. We detect 84 faint bursts with NICER, having a strong preference for occurring close to the surface emission pulse maximum-the first time this phenomenon is detected in such a large burst sample. This likely implies a very low altitude for the burst emission region and a triggering mechanism connected to the surface active zone. Finally, our radio observations at several epochs and multiple frequencies reveal no evidence of pulsed or burst-like radio emission.
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