Optical/X-ray Variability in Swift 1753.5-0127
ATel #562; R. I. Hynes (LSU), F. Mullally (UT-Austin)
on 11 Jul 2005; 02:15 UT
Credential Certification: Robert Hynes (rih@phys.lsu.edu)
Subjects: Optical, X-ray, Binary, Black Hole, Transient
Further rapid optical photometry of Swift J1753.5-0127 (Palmer et al.,
ATEL #546) was obtained at McDonald Observatory
on July 6th and 7th, simultaneously with RXTE
public observations. Observational details were exactly as for the
previous observation (Hynes & Mullally ATEL #554). Closer examination
of the optical power spectrum reveals that the apparent red-noise is
actually composed of two components. A high-frequency band-limited
noise component is superimposed on a lower-frequency component with a
steep flickering power-spectrum. The high-frequency noise correlates
fairly well with X-ray variations on both nights, but the
low-frequency component is absent in the X-ray data. The
high-frequency optical response appears smeared by a few seconds
relative to the X-rays consistent with an origin in reprocessing.
Further simultaneous observations are urged to exploit this rare
echo-mapping opportunity. Time resolutions of a second or better are
recommended.
