Bibcode
Kidger, M. R.; de Diego, J. A.
Referencia bibliográfica
Astronomy and Astrophysics Supplement Series (ISSN 0365-0138), vol. 93, April 1992, p. 1-10.
Fecha de publicación:
4
1992
Número de citas
10
Número de citas referidas
9
Descripción
The paper presents simultaneous monitoring of the BL Lacertae object
Markarian 501 obtained in the visible and near infrared using a double
photometer system on the 1.5 m Carlos Sanchez Telescope situated in El
Observatorio del Teide (Tenerife) and CCD photometry in U and B taken
with the 1 m Jacobus Kapteyn Telescope of El Observatorio del Roque de
los Muchachos (La Palma). Evidence is seen of coordinated variability on
time scales of hours in the variations in the visible and infrared. A
brief infrared flare is seen on one night which has a formal probability
of reality of approximately 99 percent and which is not seen in the B
light curve. If real, this flare presents considerable difficulties with
the framework of existing models. The results demonstrate the value of
having a single telescope equipped to observe simultaneously in two
different ranges of the spectrum. These data are compared with CCD
photometry in U and B taken at other epochs.