Spectroscopic monitoring of active galactic nuclei. II. The Seyfert-1 galaxy NGC 3516

• The authors present the results of a five month spectroscopic monitoring campaign of the Seyfert-1 galaxy NGC 3516. Using a new calibration method and applying a correction for seeing differences during the various observations they can scale the spectra to each other with a much higher accuracy than hitherto achieved. NGC 3516 shows large amplitude variations on a time scale of several weeks. Asymmetric profile variations occur on the same time scale as the continuum variations. The authors show the presence of a varying dip on the blue wing of the Hbeta profile, which is not present on the Halpha profile, and which corresponds to the absorption features previously seen in the UV emission lines of NGC 3516. From cross-correlation analysis they find a time lag of 14plusmn2 days for the Halpha and 7plusmn3 days for the Hbeta emission-line response to continuum variations

Subject headings

NATURVETENSKAP  -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)

Keyword

Experimental/ astronomical spectra

Seyfert galaxies

visible astronomical observations/ AD 1990 01 to 06

visible

spectra

Seyfert-1 galaxy

NGC 3516

calibration method

correction for seeing

amplitude

profile variations

Hbeta

Halpha profile

cross-correlation analysis

time lag

emission-line response

continuum variations

14 d

7 d

H/ A9850R Active and peculiar galaxies A9850G Radiation and spectra of galaxies A9580J Photographic region astronomical observations/ time 1.2E+06 s

time 6.0E+05 s/ H/el

Publication and Content Type

ref (subject category)

art (subject category)