Free access
Issue
Astron. Astrophys. Suppl. Ser.
Volume 116, Number 3, May_1 1996
Page(s) 403 - 407
DOI http://dx.doi.org/10.1051/aas:1996123
VRI photometry of stars in the fields of 12 BL Lacertae objects DOI: 10.1051/aas:1996123

Astronomy and Astrophysics Supplement Series, Vol. 116, May I 1996, 403-407

VRI photometry of stars in the fields of 12 BL Lacertae objects

M. Fiorucci and G. Tosti

Send offprint requests to: tosti@astrpg.pg.infn.it

Cattedra di Astrofisica, Università di Perugia, Via A. Pascoli, I-06100 Perugia, Italy

Received July 25; accepted September 8, 1995

Abstract:

We present Johnson-Cousins magnitudes of field comparison stars for twelve BL Lacertae objects belonging to the largest sample of blazars which is monitored at the Perugia University Observatory. The sequences reported here can be used in the long--term CCD photometric monitoring of BL Lac objects aimed to understand the characteristics of their variability. Finding charts for all of these comparison sequences are also included in this paper.

Key words: BL Lacertae objects: general


Copyright EDP Sciences
web@edpsciences.com

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access.

An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account.
    In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.