The Crab pulsar in the visible and ultraviolet with 20 microsecond effective time resolution

Percival, J. W.; Biggs, James D.; Dolan, J. F.; Robinson, E. L.; Taylor, Matthew; Bless, R. C.; Elliot, J. L.; Ramseyer, T. F.; Citters, G. W. van; Zhang, E.

doi:10.1086/172512

Cited by 75 publications

(92 citation statements)

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“…For instance, V − R is 0.4 for the Crab pulsar (Percival et al 1993) and 0.7 for its PWN knot (Sandberg & Sollerman 2009). An association with the point-like pulsar is, however, excluded because of the large offset, 1.…”

Section: Photometry and Colour-magnitude Diagrammentioning

confidence: 99%

Deep optical imaging of theγ-ray pulsar J1048–5832 with the VLT

Danilenko¹,

Kirichenko

Sollerman

et al. 2013

A&A

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Context. PSR J1048-5832 is a young radio-pulsar that has recently been detected in γ-rays with Fermi, and also in X-rays with Chandra and XMM-Newton. It powers a compact pulsar wind nebula visible in X-rays and is in many ways similar to the Vela pulsar. Aims. We present deep optical observations made with the ESO Very Large Telescope to search for optical counterparts of the pulsar and its nebula and to explore their multi-wavelength emission properties. Methods. The data were obtained in the V and R bands and were compared with archival data in other spectral domains. Results. We do not detect the pulsar in the optical and derive informative upper limits of R 28. m 1 and V 28. m 4 for its brightness. Using a red-clump star method, we estimate an interstellar extinction towards the pulsar of A V ≈ 2 mag, which is consistent with the absorbing column density derived from X-rays. The respective distance agrees with the dispersion measure distance. We reanalysed the Chandra X-ray data and compared the dereddened upper limits with the unabsorbed X-ray spectrum of the pulsar. We find that regarding its optical-X-ray spectral properties this γ-ray pulsar is not distinct from other pulsars detected in both ranges. However, like the Vela pulsar, it is very inefficient in the optical and X-rays. Among a dozen optical sources overlapping with the pulsar X-ray nebula we find one with V ≈ 26. m 9 and R ≈ 26. m 3, whose colour is slightly bluer than that of the field stars and is consistent with the peculiar colours typical for pulsar nebula features. It positionally coincides with a relatively bright feature of the pulsar X-ray nebula, resembling the Crab wisp and is located in ∼2 from the pulsar. We suggest this source as a counterpart candidate to the feature. Conclusions. Based on the substantial interstellar extinction towards the pulsar and its optical inefficiency, additional optical studies should be carried out at longer wavelengths.

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Section: Photometry and Colour-magnitude Diagrammentioning

confidence: 99%

Deep optical imaging of theγ-ray pulsar J1048–5832 with the VLT

Danilenko¹,

Kirichenko

Sollerman

et al. 2013

A&A

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“…The centroids and the bandpasses correspond to those of FORS1 Bessel filters (FORS1 2000). For comparison, we also plot in this figure the corresponding multi-band flux densities from the Crab (Percival et al 1993), LMC pulsar PSR B0540-69 (Middleditch et al 1987 as restated by Nasuti et al 1997), and Vela (Mignani & Caraveo 2001, dereddened fluxes from their Table 1). We note that 1024-Fnt has a spectral energy distribution similar to those of the well-known optical pulsars, as all objects have relatively flat spectra (with the exception of Vela near the R-band).…”

Section: Implications For Thermal and Non-thermal Models Of The Two Nmentioning

confidence: 99%

Deep optical observations of the fields of two nearby millisecond pulsars with the VLT

Sutaria

Ray

Reisenegger

et al. 2003

A&A

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Abstract. We report on deep VLT observations of the fields of two nearby, isolated millisecond pulsars, PSR J1744-1134 and PSR J1024-0719. Both objects are old neutron stars with characteristic age τ ≥ 10 9 yr and have relatively high spin-down flux. They have been detected earlier as X-ray sources by ROSAT HRI observations and were considered good candidates for non-thermal emission in the optical bands. Our observations set an upper limit of B = 26.9, V = 26.3 and R = 26.0 for PSR J1744-1134. In the case of PSR J1024-0719, we find two faint objects near the radio position of the pulsar. Using multiband photometry from the VLT and spectroscopy carried out with the Magellan I telescope, we discuss the nature of the brighter object and the possibility of the fainter one being the optical counterpart of PSR J1024-0719. We consider the implications of our findings for both pulsars in the context of theoretical models of high-energy emission from old pulsars.

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“…For characterizing the SED, we list in Table 1 results from some of the previous observations of the spectral index, α ν , of the Crab pulsar, and indicate for which wavelength ranges these Reference α ν λ-range (Å) Nasuti et al (1996) −0.10 ± 0.01 4900−7000 Carramiñana et al (2000) 0 .2 ± 0.1 5000−7500 Sollerman et al (2000) 0 .11 ± 0.04 1140−9250 Beskin & Neustroev (2001) −0.15 ± 0.15 5000−7050 Fordham et al (2002) −0.034 ± 0.009 4600−6000 Percival et al (1993) 0 .11 ± 0.13 1680−7400 Golden et al (2000) −0.07 ± 0.19 3700−5500 Sollerman (2003) 0 .31 ± 0.02 12 400−21 800 Sandberg & Sollerman (2009) 0.27 ± 0.03 3700−38 000 observations were made (compare Fordham et al 2002, their Table 6). The uppermost part are spectroscopic observations and the lower part are photometric.…”

Section: Spectral Energy Distributionmentioning

confidence: 99%

The location of the Crab pulsar emission region: restrictions on synchrotron emission models

Björnsson

Sandberg

Sollerman

2010

A&A

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Recent observations of the Crab pulsar show no evidence of a spectral break in the infrared regime. It is argued that the observations are consistent with a power-law spectrum in the whole observable infrared-optical range. This is taken as the starting point for evaluating of how self-consistent incoherent synchrotron models fare in a comparison with observations. Inclusion of synchrotron self-absorption proves important as does the restriction on the observed size of the emission region imposed by the relativistic beaming thought to define the pulse profile. It is shown that the observations can be used to derive two independent constraints on the distance from the neutron star to the emission region; in addition to a direct lower limit, an indirect measure is obtained from an upper limit to the magnetic field strength. Both of these limits indicate that the emission region is located at a distance considerably greater than the light cylinder radius. The implications of this result are discussed, and it is emphasized that, for standard incoherent synchrotron models to fit inside the light cylinder, rather special physical conditions need to be invoked.

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The Crab pulsar in the visible and ultraviolet with 20 microsecond effective time resolution

Cited by 75 publications

References 0 publications

Deep optical imaging of theγ-ray pulsar J1048–5832 with the VLT

Deep optical imaging of theγ-ray pulsar J1048–5832 with the VLT

Deep optical observations of the fields of two nearby millisecond pulsars with the VLT

The location of the Crab pulsar emission region: restrictions on synchrotron emission models

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