NEW:

Due to recent brightening of OQ 530 (S4 1418+546) (see BD news. 26) a TOO observation with SAX was triggered for March 3 - 4, 2000. Simultaneous observations during these nights are encouraged.

Mrk 501, March 01-11, 2000

ASCA long-look and ground-based observing campaign

A 400 ks observation of Mrk 501 will be carried out by ASCA. This is part of the ASCA long look program of the ASCA AO-8 observing program. PI of these observations is Tad Takahashi, (ISAS, Japan).

The aim of the observations is a detailed analysis of the variability properties of Mrk 501. Near-continuous observations will result in very well sampled X-ray lightcurves, covering a broad range in X-ray energies.

Simultaneous multi-frequency observations during this period are very important. The Whole Earth Blazar Telescope project WEBT is organizing a campaign for ground-based observations, coordinated by S. Wagner.

All interested parties are invited to contribute to this project. All groups contributing scientifically useful data to this multifrequency campaign will be invited to be co-authors on all joint publications of the data.

ASCA observations: Mrk501 March/01 12:00 - March/11 00:00

Simultaneous measurements in other bands during this period are requested.

We seek photometric observations in all frequency regimes, including the radio, mm, sub-mm, IR, and optical bands. Polarimetric or spectrophotometric observations are also welcome.
Imaging data which allow relative photometry (with respect to near-by stars) are sufficient, provided standard filters are used or filter transmission curves are given.
Mrk 501 is fairly bright (m(v) = 13.5 - 15.5), and most telescopes should be able to provide data of good S/N in short exposures.
A finding chart, identifying several suitable stars for relative photometry is available here. Information from NED is given here.

Anybody interested in participating is invited to contact S.Wagner@lsw.uni-heidelberg.de for additional information. Following the campaign a call for data will be given here. Either reduced photometry/flux density measurements or raw data (including calibration data) are welcome. Optical observers will be asked to provide de-biased and flatfield-corrected images.

Observatories participating (as of Feb 20):
Heidelberg observatory, Germany
Tuorla observatory, Finland
Calar Alto, Spain
La Palma, Spain
Guillermo-Haro Observatory, Mexiko
Lowell Observatory, USA
Abastumani Observatory, Georgia

Future campaigns:

There will be other long look observations with ASCA. The ASCA schedule gives preliminary dates. Calls for further campaigns will be issued here.