0235+16 radio/optical flare

[Matthias Kadler <mkadler@milkyway.gsfc.nasa.gov>]

Hi everybody,

one of "our" sources is right now having a very bright mm radio flare:

http://sma1.sma.hawaii.edu/callist.html?plot=0238%2B166

Claudia Raiteri from the WEBT told me that the optical state is also 
very high and very variable. On Sunday and Monday, Swift will observe 
the source for 10ksec each with the XRT and the four bluest filters of 
the UVOT. I have already asked Claudia to spread this among the WEBT 
partners but I wanted to let you know, as well. If anybody has 
suggestions for further complementary observations, please let me know.

This source is a BL Lac object that is famous for various reasons: EGRET 
source, possible microlensing candidate, correlated multi-wavelength 
variability, extremely compact structure almost unresolved even at 
microarcsec resolution, extreme short-term radio variability indicating 
a Doppler factor of ~100, possible 5.7yr periodicity between main 
outbursts and last but not least it has become famous for skipping its 
latest predicted outburst in spring 2004.

It is probably too early to say if this is now the delayed major 
outburst or if this flare gets stuck somewhere in the medium-amplitude 
mm regime. The latest data point from Jan 23 is already a bit lower than 
the ones from Jan 11/12. But for many years, this is certainly the most 
exciting event in this object.

Matthias

-- 
Dr. Matthias Kadler
NASA Postdoctoral Research Associate
Astrophysics Science Division
Code 662
NASA's Goddard Space Flight Center 
Greenbelt, MD 20771
tel: 301-286-4390
fax: 301-286-1684
e-mail: mkadler@milkyway.gsfc.nasa.gov