A detailed analysis of the data from a high sampling rate, multi-month reverberation mapping campaign, undertaken primarily at MDM Observatory with supporting observations from telescopes around the ...world, reveals that the Hbeta emission region within the broad-line regions (BLRs) of several nearby active galactic nuclei (AGNs) exhibits a variety of kinematic behaviors. While the primary goal of this campaign was to obtain either new or improved Hbeta reverberation lag measurements for several relatively low-luminosity AGNs, we were also able to unambiguously reconstruct velocity-resolved reverberation signals from a subset of our targets. Through high cadence spectroscopic monitoring of the optical continuum and broad Hbeta emission-line variations observed in the nuclear regions of NGC 3227, NGC 3516, and NGC 5548, we clearly see evidence for outflowing, infalling, and virialized BLR gas motions, respectively.
We present the final results from a high sampling rate, multi-month, spectrophotometric reverberation mapping campaign undertaken to obtain either new or improved H{beta} reverberation lag ...measurements for several relatively low-luminosity active galactic nuclei (AGNs). We have reliably measured the time delay between variations in the continuum and H{beta} emission line in six local Seyfert 1 galaxies. These measurements are used to calculate the mass of the supermassive black hole at the center of each of these AGNs. We place our results in context to the most current calibration of the broad-line region (BLR) R{sub BLR}-L relationship, where our results remove outliers and reduce the scatter at the low-luminosity end of this relationship. We also present velocity-resolved H{beta} time-delay measurements for our complete sample, though the clearest velocity-resolved kinematic signatures have already been published.
We present the final results from a high sampling rate, multi-month, spectrophotometric reverberation mapping campaign undertaken to obtain either new or improved Hbeta reverberation lag measurements ...for several relatively low-luminosity AGNs. We have reliably measured thetime delay between variations in the continuum and Hbeta emission line in six local Seyfert 1 galaxies. These measurements are used to calculate the mass of the supermassive black hole at the center of each of these AGNs. We place our results in context to the most current calibration of the broad-line region (BLR) R-L relationship, where our results remove outliers and reduce the scatter at the low-luminosity end of this relationship. We also present velocity-resolved Hbeta time delay measurements for our complete sample, though the clearest velocity-resolved kinematic signatures have already been published.
A detailed analysis of the data from a high sampling rate, multi-month reverberation mapping campaign, undertaken primarily at MDM Observatory with supporting observations from telescopes around the ...world, reveals that the Hbeta emission region within the broad line regions (BLRs) of several nearby AGNs exhibit a variety of kinematic behaviors. While the primary goal of this campaign was to obtain either new or improved Hbeta reverberation lag measurements for several relatively low luminosity AGNs (presented in a separate work), we were also able to unambiguously reconstruct velocity-resolved reverberation signals from a subset of our targets. Through high cadence spectroscopic monitoring of the optical continuum and broad Hbeta emission line variations observed in the nuclear regions of NGC 3227, NGC 3516, and NGC 5548, we clearly see evidence for outflowing, infalling, and virialized BLR gas motions, respectively.
High purity, mirror-polished polycrystalline Cu surface was treated with single picosecond laser pulses at fluence levels close to the single-pulse modification threshold. The induced surface ...topography and sub-surface changes were examined with scanning and transmission electron microscopy, respectively. The analysis showed an increased absorption of laser energy on the microscopic surface topography inhomogeneities, even at a fluence level below the modification threshold. Many features, like spikes, bubbles, spheres, as well as small periodic ripples at the bottom of scratches, reveal a significant influence of melting and eruptive relaxation of the absorbed laser energy on the final appearance of the surface. Further, it was found that thermal stresses result in twinning to a depth of few tens of nanometers under the surface. Voids at this depth have been observed as well. The results of the observations provide new insights into the early stages of the picosecond laser pulse modification of metals, especially metals with a weak electron-phonon coupling.
Surface Melting Of Copper By Ultrashort Laser Pulses J. Vincenc Oboňa1; V. Ocelík1; J. Th. M. De Hosson1 ...
WIT Transactions on Engineering Sciences,
01/2011, Letnik:
71
Journal Article, Conference Proceeding
Odprti dostop
The main advantage of ultrashort laser pulses in manufacturing technology is their very high removal rate of material and high quality of microstructures with the smallest dimensions at 1 μm level. ...The accuracy is mainly due to an almost absence of thermal diffusion into bulk material. In this paper we report the investigation on polycrystalline Cu sample surface treated by 6.7 ps laser pulses with 1030 nm laser light wavelength. Scanning electron microscopy micrographs reveal the presence of jet-like structures with spherical drop-like endings, solidified spheres and many bubble bursts at even lower fluence than the threshold value for the ablation is. Within the molten material the jet-like features are due to an explosion of bubbles originated in solid-liquid-vapor transitions. In the case of below-threshold irradiation, the same objects can be seen along surface scratches, dot contaminations etc., which indicate an increase of the laser light absorption on these inhomogeneities.
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