ULTRACAM: an ultrafast, triple-beam CCD camera for high-speed astrophysics

Dhillon, V. S.; Marsh, T. R.; Stevenson, Mark; Atkinson, David; Kerry, P.; Peacocke, P. T.; Vick, Andy; Beard, S. M.; Ives, Derek; Lunney, D.; McLay, Stewart; Tierney, Chris; Kelly, James R.; Littlefair, S. P.; Nicholson, Rhana B.; Pashley, R.; Harlaftis, E. T.; O’Brien, Kieran

doi:10.1111/j.1365-2966.2007.11881.x

Cited by 321 publications

(242 citation statements)

References 41 publications

(13 reference statements)

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“…We obtained photometry of WASP 1628+10 using the multichannel photometer Ultracam (Dhillon et al 2007) mounted on the William Herschel 4.2-m telescope at the Observatorio del Roque de los Muchachos. Images of WASP 1628+10 and the comparison star TYC 964-558-1 were obtained simultaneously through u', g' and r' filters with an exposure time of 0.55 seconds for the g' and r' images and 1.65 seconds for the u' images.…”

Section: Photometrymentioning

confidence: 99%

WASP 1628+10 – an EL CVn-type binary with a very low mass stripped red giant star and multiperiodic pulsations

Maxted¹,

Serenelli²,

Marsh³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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The star 1SWASP J162842.31+101416.7 (WASP 1628+10) is one of several EL CVntype stars recently identified using the WASP database, i.e., an eclipsing binary star in which an A-type dwarf star (WASP 1628+10 A) eclipses the remnant of a disrupted red giant star (WASP 1628+10 B). We have measured the masses, radii and luminosities of the stars in WASP 1628+10 using photometry obtained in three bands (u', g', r') with the Ultracam instrument and medium-resolution spectroscopy. The properties of the remnant are well-matched by models for stars in a rarely-observed state evolving to higher effective temperatures at nearly constant luminosity prior to becoming a very low-mass white dwarf composed almost entirely of helium, i.e., we confirm that WASP 1628+10 B is a pre-He-WD. WASP 1628+10 A appears to be a normal A2 V star with a mass of 1.36 ± 0.05M ⊙ . By fitting models to the spectrum of this star around the Hγ line we find that it has an effective temperature T eff,A = 7500 ± 200 K and a metallicity [Fe/H] = −0.3±0.3. The mass of WASP 1628+10 B is only 0.135±0.02M ⊙ . The effective temperature of this pre-He-WD is approximately 9200 K. The Ultracam photometry of WASP 1628+10 shows variability at several frequencies around 40 cycles per day, which is typical for δ Sct-type pulsations often observed in early A-type stars like WASP 1628+10 A. We also observe frequencies near 114 cycles/day and 129 cycles/day, much higher than the frequencies normally seen in δ Sct stars. Additional photometry through the primary eclipse will be required to confirm that these higher frequencies are due to pulsations in WASP 1628+10 B. If confirmed, this would be only the second known example of a pre-He-WD showing high-frequency pulsations.

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Section: Photometrymentioning

confidence: 99%

WASP 1628+10 – an EL CVn-type binary with a very low mass stripped red giant star and multiperiodic pulsations

Maxted¹,

Serenelli²,

Marsh³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…ULTRACAM is a high-speed, triple-beam CCD camera (Dhillon et al 2007) capable of acquiring simultaneous images in three different photometric bands. For HS 0220+0603 we used the SDSS u , g , and i filters (see Table 1).…”

Section: Wht/ultracam Fast Photometrymentioning

confidence: 99%

Dynamical masses of a nova-like variable on the edge of the period gap

Rodríguez‐Gil

Shahbaz

Marsh

et al. 2015

Mon. Not. R. Astron. Soc.

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We present the first dynamical determination of the binary parameters of an eclipsing SW Sextantis star in the 3-4 hour orbital period range during a low state. We obtained time-resolved optical spectroscopy and photometry of HS 0220+0603 during its 2004-2005 low brightness state, as revealed in the combined SMARTS, IAC80 and M1 Group long-term optical light curve.The optical spectra taken during primary eclipse reveal a secondary star spectral type of M5.5±0.5 as derived from molecular band-head indices. The spectra also provide the first detection of a DAB white dwarf in a cataclysmic variable. By modelling its optical spectrum we estimate a white dwarf temperature of 30 000 ± 5 000 K.By combining the results of modelling the white dwarf eclipse from ULTRA-CAM light curves with those obtained by simultaneously fitting the emission-and absorption-line radial velocity curves and I-band ellipsoidal light curves, we measure the stellar masses to be M 1 = 0.87 ± 0.09 M and M 2 = 0.47 ± 0.05 M for the white dwarf and the M dwarf, respectively, and an inclination of the orbital plane of i ≈ 79 o . A radius of 0.0103 ± 0.0007 R is obtained for the white dwarf. The secondary star in HS 0220+0603 is likely too cool and undersized for its mass.

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“…Dedicated fast optical photometers with good quantum efficiency (e.g. Kanbach et al 2003;Dhillon et al 2007) as well as fast modes implemented in existing near-infrared detectors, allow us to tackle old questions from a new perspective. The fastest timescales of the accretion onto stellar-mass BHs are now accessible for studying in the synchrotron emission from both the very same electron population responsible for the X-ray Comptonized emission, and -at longer wavelengths -the electron population outflowing in the relativistic jet.…”

Section: Multi-wavelength Variability Tools and Techniquesmentioning

confidence: 99%

Multi-Wavelength Variability

Uttley

Casella

2014

Space Sci Rev

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Multiwavelength variability data, combined with spectral-timing analysis techniques, provides information about the causal relationship between different physical components in accreting black holes. Using fast-timing data and long-term monitoring, we can probe the behaviour of the same components across the black hole mass scale. In this chapter we review the observational status of multiwavelength variability in accreting black holes, from black hole X-ray binaries to AGN, and consider the implications for models of accretion and ejection, primarily considering the evidence for accretion disc and jet variability in these systems. We end with a consideration of future prospects in this quickly-developing field.

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ULTRACAM: an ultrafast, triple-beam CCD camera for high-speed astrophysics

Cited by 321 publications

References 41 publications

WASP 1628+10 – an EL CVn-type binary with a very low mass stripped red giant star and multiperiodic pulsations

WASP 1628+10 – an EL CVn-type binary with a very low mass stripped red giant star and multiperiodic pulsations

Dynamical masses of a nova-like variable on the edge of the period gap

Multi-Wavelength Variability

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