Cropper and Pulsipher families

Cropper, Kenneth L.

doi:10.1093/nq/clxix.sep21.206c

Cited by 10 publications

(13 citation statements)

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“…The observational evidence is the fact that IP hard-Xray lightcurves never go to zero flux [as occurs in AM Her stars when only one pole accretes and that pole is on the far side of the white dwarf]. Indeed, when the 'IP' RX 1914+24 was observed to have zero flux for half its cycle, Cropper et al (1998a) proposed that it must be an ultra-short-period AM Her star, which appears to have been confirmed by further data (Ramsay et al, this volume).…”

Section: X-ray Pulse Profilesmentioning

confidence: 99%

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The Intermediate Polars

Hellier

1996

Cataclysmic Variables and Related Objects

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Section: X-ray Pulse Profilesmentioning

confidence: 99%

“…Owing to ROSAT we know of three IPs (PQ Gem, V405 Aur & UU Col; Mason et al 1992;Haberl et al 1994;Burwitz et al 1996) that show soft black-body components similar to those in AM Her stars (a fourth star, RX 1914+24, I now class as an AM Her, see Cropper et al 1998a).…”

Section: Soft Ipsmentioning

confidence: 99%

The Intermediate Polars

Hellier

1996

Cataclysmic Variables and Related Objects

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“…Instead, either a truncated disc is formed or the accretion flow is channeled directly onto the magnetic pole regions of the white dwarf. Those mCVs which have B >10 MG are called AM Herculis systems or 'Polars', on account of their high levels of optically polarised light (see Cropper (1990) and Warner (1995) for reviews).…”

Section: Introductionmentioning

confidence: 99%

TESS observations of the asynchronous polar CD Ind: mapping the changing accretion geometry

Hakala

Ramsay

Potter

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present the results of near continuous TESS optical observations of the asynchronous polar CD Ind (RX J2115-5840). The 27.9 d long light curve, with 2 min resolution, reveals remarkable changes in the magnetic accretion geometry of the system over the 7.3 d beat period. We have modelled the changes in the optical spin period pulse shape using a cyclotron emission mapping technique. The resulting cyclotron emission maps of the magnetic white dwarf reveal how the accretion geometry changes from single to two pole accretion and back over the beat cycle. Finally, we present the results from particle based numerical magnetic accretion simulations, that agree with our interpretation of the changing accretion scenario.

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“…The Euclid Visible Instrument (VIS) will contain a focal plane of 36 e2v CCDs, each of 4k × 4k pixels, each 12 µm square [5][6][7]. Euclid VIS will perform weak gravitational lensing measurements, investigating shape changes in galaxies.…”

Section: Observing Lower Signals In Space Astronomymentioning

confidence: 99%

Challenges in photon-starved space astronomy in a harsh radiation environment using CCDs

et al. 2015

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The Charge Coupled Device (CCD) has a long heritage for imaging and spectroscopy in many space astronomy missions. However, the harsh radiation environment experienced in orbit creates defects in the silicon that capture the signal being transferred through the CCD. This radiation damage has a detrimental impact on the detector performance and requires carefully planned mitigation strategies.The ESA Gaia mission uses 106 CCDs, now orbiting around the second Lagrange point as part of the largest focal-plane ever launched. Following readout, signal electrons will be affected by the traps generated in the devices from the radiation environment and this degradation will be corrected for using a charge distortion model. ESA's Euclid mission will contain a focal plane of 36 CCDs in the VIS instrument. Moving further forwards, the World Space Observatory (WSO) UV spectrographs and the WFIRST-AFTA coronagraph intend to look at very faint sources in which mitigating the impact of traps on the transfer of single electron signals will be of great interest.Following the development of novel experimental and analysis techniques, one is now able to study the impact of radiation on the detector to new levels of detail. Through a combination of TCAD simulations, defect studies and device testing, we are now probing the interaction of single electrons with individual radiation-induced traps to analyse the impact of radiation in photon-starved applications.

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Cropper and Pulsipher families

Cited by 10 publications

References 0 publications

The Intermediate Polars

The Intermediate Polars

TESS observations of the asynchronous polar CD Ind: mapping the changing accretion geometry

Challenges in photon-starved space astronomy in a harsh radiation environment using CCDs

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