A spectroscopic and photometric study of short-timescale variability in NGC 5548статья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Results of a ground-based optical monitoring campaign on NGC 5548 in June 1998 are presented. The broad-band fluxes (U, B, V), and the spectrophotometric optical continuum flux F$_lambda$ (5100 Å) monotonically decreased in flux while the broad-band R and I fluxes and the integrated emission-line fluxes of Hα and Hβ remained constant to within 5%. On June 22, a short continuum flare was detected in the broad band fluxes. It had an amplitude of about ~ 18% and it lasted only ~90 min. The broad band fluxes and the optical continuum F$_lambda$ (5100 Å) appear to vary simultaneously with the EUV variations. No reliable delay was detected for the broad optical emission lines in response to the EUVE variations. Narrow Hβ emission features predicted as a signature of an accretion disk were not detected during this campaign. However, there is marginal evidence for a faint feature at lambda =~ 4962 Å with FWHM =~ 6 Å redshifted by Delta v =~ 1100 km s$^-1$ with respect to Hβ$_narrow$. Based on observations taken at the German-Spanish Astronomical Centre Calar Alto, Mt. Hopkins Observatory, Crimean Observatory, SAO, University of Nebraska Observatory. Tables 1A and 3A are only available at CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcct?/A+A/371/79