Optical Spectrum of Main‐, Inter‐, and Off‐Pulse Emission from the Crab Pulsar

Carramiñana, A.; Čadež, A.; Zwitter, T.

doi:10.1086/317063

Cited by 14 publications

(13 citation statements)

References 11 publications

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“…Significant variations are apparent, especially in the B/V data, but after dividing out the predicted variations due to pile-up, there is no longer any strong evidence for colour changes across the pulse profile. This is consistent with previous studies in the UV-optical-IR band, which have reported either no colour changes (e.g., Carramiñana et al 2000), or very slight ones (e.g., Eikenberry et al 1996, Romani et al 2001. This suggests that the pile-up characteristics of S-Cam2 are well understood, at least in the count rate regime probed by the Crab.…”

Section: Spectral Distortion Due To Pile-upsupporting

confidence: 92%

Temperature determination via STJ optical spectroscopy

Reynolds

Bruijne

Perryman

et al. 2003

A&A

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Abstract. ESA's Superconducting Tunnel Junction (STJ) optical photon-counting camera (S-Cam2) incorporates an array of pixels with intrinsic energy sensitivity. Using the spectral fitting technique common in X-ray astronomy, we fit black bodies to nine stellar spectra, ranging from cool flare stars to hot white dwarfs. The measured temperatures are consistent with literature values at the expected level of accuracy based on the predicted gain stability of the instrument. Having also demonstrated that systematic effects due to count rate are likely to be small, we then proceed to apply the temperature determination method to four cataclysmic variable (CV) binary systems. In three cases we measure the temperature of the accretion stream, while in the fourth we measure the temperature of the white dwarf. The results are discussed in the context of existing CV results. We conclude by outlining the prospects for future versions of S-Cam.

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Section: Spectral Distortion Due To Pile-upsupporting

confidence: 92%

Temperature determination via STJ optical spectroscopy

Reynolds

Bruijne

Perryman

et al. 2003

A&A

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“…The absence of this feature is also noted by Sollerman et al (2000) and Carramiñana et al (2000). Is the result of Nasuti et al then wrong?…”

Section: Resultsmentioning

confidence: 87%

“…Its consequences might have appeared 1.5 years later during the observations of Nasuti et al (1996). The observations of Carramiñana et al (2000) were conducted 18 days after the glitch in October 1999, but here the frequency jump and the relaxation time were close to a minimum.…”

Section: Resultsmentioning

confidence: 96%

Spectroscopy of the Crab Pulsar

Beskin

Neustroev

2001

A&A

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Abstract. We present new, high signal-to-noise spectroscopy of the Crab Pulsar in the range λλ5000−7000Å.The observations were carried out with the 6-meter telescope of the SAO with the spectrograph SP-124 with a resolution of 2Å. After reduction of the Crab Nebula emission, the dereddened pulsar spectrum can be fitted by a power law with α = −0.15 ± 0.15. There are no lines (emission and absorption) with a relative intensity (depth) of more than 2% (with a confidential probability of 99%). At this level we did not find absorption at λ6000Å, possibly of ion-cyclotron origin, as detected by Nasuti et al. (1996). This detail can be variable as a consequence of the variability of the ion ejection from the neutron star (NS) surface. We suggest a possible relationship between ejection intensity and inhomogeneity of the NS surface connected with pulsar glitches.

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“…We estimate the number distribution of photons detected as a function of wavelength in order to determine our effective observing wavelength. The spectrum of the Crab Pulsar at optical and near-infrared wavelengths is known to follow an empirically-measured power law (Carramiñana et al 2000). Using MODTRAN (Berk et al 1987) to estimate the transmission of the atmosphere due to Rayleigh scattering and telluric absorption, and taking into account the manufacturer-provided transfer functions of each optical component (two achromatic lenses, a detector quantum efficiency curve, as well as a pair of dichroic beamsplitters), we are able to compute up to an overall multiplicative constant the underlying number distribution versus wavelength of the Crab photons detected.…”

Section: Observations Of the Crab Pulsarmentioning

confidence: 99%

Testing the Weak Equivalence Principle Using Optical and Near-infrared Crab Pulses

Leung

Harris

et al. 2018

ApJ

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The Weak Equivalence Principle states that the geodesics of a test particle in a gravitational field are independent of the particle's constitution. To constrain violations of the Weak Equivalence Principle, we use the one-meter telescope at Table Mountain Observatory near Los Angeles to monitor the relative arrival times of pulses from the Crab Pulsar in the optical (λ ≈ 585 nm) and near-infrared (λ ≈ 814 nm) using an instrument which detects single photons with nanosecond-timing resolution in those two bands. The infrared pulse arrives slightly before the visible pulse. Our three analysis methods give delays with statistical errors of ∆t obs = 7.41±0.58, 0.4±3.6, and 7.35±4.48 microseconds (at most 1/4000 of the pulsar period). We attribute this discrepancy to systematic error from the fact that the visible and infrared pulses have slightly different shapes. Whether this delay emerges from the pulsar, is caused by passing through wavelength-dependent media, or is caused by a violation of the equivalence principle, unless there is a fine-tuned cancellation among these, we set the first upper limit on the differential post-Newtonian parameter at these wavelengths of ∆γ < 1.07 × 10 −10 (3σ). This result falls in an unexplored region of parameter space and complements existing limits on equivalence-principle violation from fast radio bursts, gamma ray bursts, as well as previous limits from the Crab.

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Optical Spectrum of Main‐, Inter‐, and Off‐Pulse Emission from the Crab Pulsar

Cited by 14 publications

References 11 publications

Temperature determination via STJ optical spectroscopy

Temperature determination via STJ optical spectroscopy

Spectroscopy of the Crab Pulsar

Testing the Weak Equivalence Principle Using Optical and Near-infrared Crab Pulses

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