1,723,105 research outputs found
Optical observations of psr j0205+6449
No full textPSR J0205+6449 is an X-ray and radio pulsar in supernova (SN) remnant 3C 58. We report on observations of the central region of 3C 58 using the 4.2-m William Herschel Telescope at the Isaac Newton Group of Telescopes, La Palma, with the intention of identifying the optical counterpart of PSR J0205+6449 and characterizing its pulsar wind nebula (PWN). Around the pulsar position, we identified extended emission with a magnitude of B = 23.97 +/- 0.10 ag, V = 22.95 +/- 0.05 mag and R = 22.15 +/- 0.03 mag consistent with a PWN. From the R-band image, we identified three knots with m(R) = 24.08 +/- 0.07 mag (o1), 24.15 +/- 0.07 mag (o2) and 24.24 +/- 0.08 mag (o3). We confirm the presence of an optical PWN around PSR J0205+6449 and give an upper limit of m(R) approximate to 24 for the optical magnitude of the pulsar. Furthermore, we make the tentative suggestion that our object o1, with an m(R) approximate to 24.08, is the optical counterpart. If confirmed, the pulsar would have an L-R/L-X approximate to 0.004 and an optical efficiency of about five per cent of the Crab pulsar. Such a low efficiency is more consistent with the characteristic age of the pulsar rather than that of SN 1181.peer-reviewe
Optical Observations of PSR J0205+6449
No full textPSR J0205+6449 is a X-ray and radio pulsar in supernova remnant 3C 58. We report on observations of the central region of 3C 58 using the 4.2-m William Herschel Telescope with the intention of identifying the optical counterpart of PSR J0205+6449 and characterising its pulsar wind nebula. Around the pulsar position we identified extended emission with a magnitude of , and consistent with a pulsar wind nebula. From the R-band image we identified three knots with = (o1), (o2) and (o3). We confirm the presence of an optical pulsar wind nebula around PSR J0205+6449 and give an upper limit of 24 for the optical magnitude of the pulsar. Furthermore we make the tentative suggestion that our object o1, with an 24.08 is the optical counterpart. If confirmed the pulsar would have an and an optical efficiency of about 5% of the Crab pulsar. Such a low efficiency is more consistent with the characteristic age of the pulsar rather than that of SN 1181
Optical observations of psr j0205+6449
No full textPSR J0205+6449 is an X-ray and radio pulsar in supernova (SN) remnant 3C 58. We report on observations of the central region of 3C 58 using the 4.2-m William Herschel Telescope at the Isaac Newton Group of Telescopes, La Palma, with the intention of identifying the optical counterpart of PSR J0205+6449 and characterizing its pulsar wind nebula (PWN). Around the pulsar position, we identified extended emission with a magnitude of B = 23.97 +/- 0.10 ag, V = 22.95 +/- 0.05 mag and R = 22.15 +/- 0.03 mag consistent with a PWN. From the R-band image, we identified three knots with m(R) = 24.08 +/- 0.07 mag (o1), 24.15 +/- 0.07 mag (o2) and 24.24 +/- 0.08 mag (o3). We confirm the presence of an optical PWN around PSR J0205+6449 and give an upper limit of m(R) approximate to 24 for the optical magnitude of the pulsar. Furthermore, we make the tentative suggestion that our object o1, with an m(R) approximate to 24.08, is the optical counterpart. If confirmed, the pulsar would have an L-R/L-X approximate to 0.004 and an optical efficiency of about five per cent of the Crab pulsar. Such a low efficiency is more consistent with the characteristic age of the pulsar rather than that of SN 1181
Optical Observations of PSR J0205+6449
No full textPSR J0205+6449 is a X-ray and radio pulsar in supernova remnant 3C 58. We report on observations of the central region of 3C 58 using the 4.2-m William Herschel Telescope with the intention of identifying the optical counterpart of PSR J0205+6449 and characterising its pulsar wind nebula. Around the pulsar position we identified extended emission with a magnitude of B = 23 \fm 97 \pm 0.10, V = 22 \fm 95 \pm 0.05 and R = 22 \fm 15 \pm 0.03 consistent with a pulsar wind nebula. From the R-band image we identified three knots with = 24 \fm 08 \pm 0.07 (o1), 24 \fm 15 \pm 0.07 (o2) and 24 \fm 24 \pm 0.08 (o3). We confirm the presence of an optical pulsar wind nebula around PSR J0205+6449 and give an upper limit of 24 for the optical magnitude of the pulsar. Furthermore we make the tentative suggestion that our object o1, with an 24.08 is the optical counterpart. If confirmed the pulsar would have an and an optical efficiency of about 5% of the Crab pulsar. Such a low efficiency is more consistent with the characteristic age of the pulsar rather than that of SN 1181.peer-reviewe
Optical observations of psr j0205+6449 – the next optical pulsar?
No full textPSR J0205+6449 is a young (similar to 5400 yr), Crab-like pulsar detected in radio and at X-ray and gamma-ray energies and has the third largest spin-down flux among known rotation-powered pulsars. It also powers a bright synchrotron nebula detected in the optical and X-rays. At a distance of similar to 3.2 kpc and with an extinction comparable to the Crab, PSR J0205+6449 is an obvious target for optical observations. We observed PSR J0205+6449 with several optical facilities, including 8m class ground-based telescopes, such as the Gemini and the Gran Telescopio Canarias. We detected a point source, at a significance of 5.5 sigma, of magnitude i\u27 similar to 25.5, at the centre of the optical synchrotron nebula, coincident with the very accurate Chandra and radio positions of the pulsar. Thus, we discovered a candidate optical counterpart to PSR J0205+6449. The pulsar candidate counterpart is also detected in the g\u27 (similar to 27.4) band and weakly in the r\u27 (similar to 26.2) band. Its optical spectrum is fitted by a power law with photon index Gamma(O) = 1.9 +/- 0.5, proving that the optical emission, if of non-thermal origin, is as expected for a young pulsar. The optical photon index is similar to the X-ray one (Gamma(X) = 1.77 +/- 0.03), although the optical fluxes are below the extrapolation of the X-ray power spectrum. This would indicate the presence of a double spectral break between the X-ray and optical energy range, at variance with what is observed for the Crab and Vela pulsars, but similar to the Large Magellanic Cloud pulsar PSR B0540-69
Optical observations of psr j0205+6449 – the next optical pulsar?
No full textPSR J0205+6449 is a young (similar to 5400 yr), Crab-like pulsar detected in radio and at X-ray and gamma-ray energies and has the third largest spin-down flux among known rotation-powered pulsars. It also powers a bright synchrotron nebula detected in the optical and X-rays. At a distance of similar to 3.2 kpc and with an extinction comparable to the Crab, PSR J0205+6449 is an obvious target for optical observations. We observed PSR J0205+6449 with several optical facilities, including 8m class ground-based telescopes, such as the Gemini and the Gran Telescopio Canarias. We detected a point source, at a significance of 5.5 sigma, of magnitude i' similar to 25.5, at the centre of the optical synchrotron nebula, coincident with the very accurate Chandra and radio positions of the pulsar. Thus, we discovered a candidate optical counterpart to PSR J0205+6449. The pulsar candidate counterpart is also detected in the g' (similar to 27.4) band and weakly in the r' (similar to 26.2) band. Its optical spectrum is fitted by a power law with photon index Gamma(O) = 1.9 +/- 0.5, proving that the optical emission, if of non-thermal origin, is as expected for a young pulsar. The optical photon index is similar to the X-ray one (Gamma(X) = 1.77 +/- 0.03), although the optical fluxes are below the extrapolation of the X-ray power spectrum. This would indicate the presence of a double spectral break between the X-ray and optical energy range, at variance with what is observed for the Crab and Vela pulsars, but similar to the Large Magellanic Cloud pulsar PSR B0540-69.peer-reviewe
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
