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An 8 month monitoring campaign on the Seyfert 1 galaxy Fairall 9 has been conducted with the International Ultraviolet Explorer in an attempt to obtain reliable estimates of continuum-continuum and continuum-emission-line delays for a high-luminosity active galactic nucleus (AGN). While the results of this campaign are more ambiguous than those of previous monitoring campaigns on lower luminosity sources, we find general agreement with the earlier results: (1) there is no measurable lag between ultraviolet continuum bands, and (2) the measured emission-line time lags are very short. It is especially notable that the Lyα + N v emission-line lag is about 1 order of magnitude smaller than determined from a previous campaign by Clavel, Wamsteker, & Glass (1989) when Fairall 9 was in a more luminous state. In other well-monitored sources, specifically NGC 5548 and NGC 3783, the highest ionization lines are found to respond to continuum variations more rapidly than the lower ionization lines, which suggests a radially ionization-stratified broad-line region. In this case, the results are less certain, since none of the emission-line lags are very well determined. The best-determined emission line lag is Lyα + N v, for which we find that the centroid of the continuum-emission-line cross-correlation function is τcent ≈ 14-20 days. We measure a lag τcent ≲ 4 days for He II λ1640; this result is consistent with the ionization-stratification pattern seen in lower luminosity sources, but the relatively large uncertainties in the emission-line lags measured here cannot rule out similar lags for Lyα + N v and He II λ1640 at a high level of significance. We are unable to determine a reliable lag for C IV λ1550, but we note that the profiles of the variable parts of Lyα and C IV λ1550 are not the same, which does not support the hypothesis that the strongest variations in these two lines arise in the same region.

Aims. Spiral structure is a prominent feature in many disk galaxies and is often outlined by bright, young objects. We study the distribution of young stellar clusters in grand-design spiral galaxies and thereby determine whether strong spiral perturbations can influence star formation. Methods. Deep, near-infrared JHK-maps were observed for ten nearby, grand-design, spiral galaxies using HAWK-I at the Very Large Telescope. Complete, magnitude-limited candidate lists of star-forming complexes were obtained by searching within the K-band maps. The properties of the complexes were derived from (H - K) - (J - H) diagrams including the identification of the youngest complexes (i.e. ⩽7 Myr) and the estimation of their extinction. Results. Young stellar clusters with ages ⩽7Myr have significant internal extinction in the range of Av = 3-7m, while older ones typically have AV<1m. The cluster luminosity function (CLF) is well-fitted by a power law with an exponent of around -2 and displays no evidence of a high luminosity cut-off. The brightest cluster complexes in the disk reach luminosities of MK = -15m5 or estimated masses of 106 Mʘ. At radii with a strong, two-armed spiral pattern, the star formation rate in the arms is higher by a factor of 2-5 than in the inter-arm regions. The CLF in the arms is also shifted towards brighter MK by at least 04. We also detect clusters with colors compatible with Large Magellanic Cloud intermediate age clusters and Milky Way globular clusters. The (J - K) - MK diagram of several galaxies shows, for the brightest clusters, a clear separation between young clusters that are highly attenuated by dust and older ones with low extinction. Conclusions. The gap in the (J - K) - MK diagrams implies that there has been a rapid expulsion of dust at an age around 7 Myr, possibly triggered by supernovae. Strong spiral perturbations concentrate the formation of clusters in the arm regions and shifts their CLF towards brighter magnitudes. [ABSTRACT FROM AUTHOR]

The Fanaroff–Riley II-type radiosource J 133658.3-295105, which is also an X-ray source, appears to be projected onto the disc of the barred-spiral galaxy NGC 5236 (M 83) at about 1.2 kiloparsecs from the galaxy's optical nucleus. J 133658.3-295105, its radio-lobes, and two other radiosources, neither of which are supernovae remnants or HII regions, are aligned with the optical nucleus of NGC 5236. Due to this peculiar on-the-sky projection, we studied J 133658.3-295105 using GEMINI+GMOS optical spectroscopy and also reanalyzed Chandra spectroscopy which was carried out in 2000. We marginally detected the Hα emission line receding at 130 km/sec with respect to the optical nucleus. We also demostrate that J 133658.3-295105 presents the Fe–Kα emission line at a redshift z = 0.018 ± 0.01. Both, Hα and Fe–Kα present redshifts that are compatible with the distance of NGC 5236. That findings reinforce the scenario of a local object for J 133658.3-295105, which could have been ejected from the nucleus of NGC 5236. [ABSTRACT FROM AUTHOR]