Observers started observing these systems with optical telescopes.
|Optical Variability||V||V + OVV||OVV||V||V|
RQ =Radio quiet BEL = Broad Emission Lines
RL = Radio Loud NEL = Narrow Emission Lines
PL = Power Law TH = Thermal
V = Variable OVV = Optically Violent Variables
Blazars = BL Lacs and OVV quasars
Blazars are a subset of Quasi-Stellar Objects.
QSO's - Compact, star-like extragalactic objects with:
QSS - Radio Quiet Quasars
Parameters of a gravitational Lens
Characteristics of a Lensing System
If the lens (or source) is in motion relative to the source (or lens) or observer moves, AND image resolution is below angular separation, we see amplitude or brightness changes, so called High Amplitude Events (HAE's).
What to expect from a High Amplitude Lensing Event.
AO 0235+164 as a Gravitational Lens system
Ostriker and Vietri (1985) suggests that BL Lacs high brightness temperature might be due to microlensing.
Paczynski (1986) and Kayser et al. (1987)Schneider and Weiss (1987) analyze scenarios for microlensing for blazars. Concludes that microlensing is a viable explanation for variability in at least some sources.
Kayser (A.Ap. 206,L8, 1988) applied microlensing to AO 0235+164. They conclude that "… intense optical outbursts are unlikely to be high amplitude events due to microlensing…" Primary objection is timescales for radio and optical events, plus creation of superluminal blobs are inconsistent with microlensing.
Stickel, Fried and Kuhr (A.Ap. 198, L13, 1988) conclude that the optical events are likely to be microlensing, the superluminal radio blobs are radio images of the central core, and not intrinsic expansion as previously thought!
The 1997 Outburst of AO 0235+164: Evidence for a Microlensing Event. Webb, Howard, Benitez, Balonek, McGrath, Shrader, Robson and Jenkins. A. J. 120, 41, 2000.
Monitoring data of AO 0235+164 throughout an energetic outburst in three frequency, optical, millimeter, and Ghz radio, plus an x-ray observation.
A 5-magnitude outburst (~ factor of 100 in brightness) over 800 days (Earth ref. frame)
Maximum Luminosity (assuming no beaming) of 9.8x1046 ergs/sec. (previous outbusrts exceeded 1049 ergs/sec.
Outburst exhibited a double-peaked morphology, and durations, amplitudes and morphologies are similar in each frequency band.
Outbursts are consistent with being simultaneous in all three frequency bands, optical, mm, and radio.