English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present optical observations of the low-luminosity Seyfert 1 nucleus ofNGC 4395, as part of a multiwavelength reverberation-mapping program.Observations were carried out over two nights in 2004 April at Lick, Wise, andKitt Peak Observatories. We obtained V-band and B-band photometry, and spectraover the range 3500-6800 Angstroms. Simultaneous Hubble Space Telescope UV andChandra X-ray observations are presented in companion papers. Even though NGC4395 was in an extremely low state of activity, we detect significant continuumvariability of 2-10%, increasing toward shorter wavelengths. The continuumlight curves, both spectroscopic and photometric, are qualitatively similar tothe simultaneous UV and X-ray light curves. Inter-band cross-correlationssuggest that the optical continuum emission lags behind the UV continuumemission by 24 +7/-9 min, and that the optical continuum emission lags behindthe X-ray continuum emission by 44 +/- 13 min, consistent with a reprocessingmodel for active galactic nucleus emission. There are also hints of Balmeremission lines lagging behind the optical continuum by an amount slightlylarger than the emission-line lag detected in the UV. These results are allsimilar to those of other Seyfert 1 nuclei. The emission-line lag yields a massmeasurement of the central black hole, which although not very significant, isconsistent with the value derived from the simultaneous UV data.Comment: 29 pages, 16 figures, emulateapj, accepted for publication in Ap

Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. III. Optical Variability and X‐Ray/UV/Optical Correlations