Parsec-scale dust distributions in Seyfert galaxies - Results of the MIDI AGN snapshot survey Export

@article{citeulike:4238935, abstract = {The emission of warm dust dominates the mid-infrared spectra of active galactic nuclei (AGN). Only interferometric observations provide the necessary angular resolution to resolve the nuclear dust and study its distribution and properties. The investigation of dust in AGN cores is hence one of the main science goals for the MID-infrared interferometric Instrument MIDI at the VLTI. In a first step, the feasibility of AGN observations was verified and the most promising sources for detailed studies were identified. To this end, we carried out a "snapshot survey" with MIDI using Guaranteed Time Observations. In the survey, observations were attempted for 13 of the brightest AGN in the mid-infrared, which are visible from Paranal. The results of the three brightest sources have been published in separate papers. Here we present the interferometric observations for the remaining 10, fainter AGN. For 8 of these, interferometric measurements could be carried out. Size estimates or limits on the spatial extent of the AGN-heated dust can be derived from the interferometric data of 7 AGN. These indicate that the dust distributions are compact, with sizes on the order of a few parsec. The derived sizes roughly scale with the square root of the luminosity in the mid-infrared, s \~{} sqrt(L), with no clear differences between type 1 and type 2 objects. This is in agreement with nearly optically thick dust structures heated to T \~{} 300 K. For several sources, we tentatively detect the 10 micron feature due to silicates either in emission or in absorption. Based on the results for all AGN studied with MIDI so far, it seems that in the mid-infrared the individual differences between galactic nuclei are greater than the generic differences between type 1 and type 2 objects.}, archivePrefix = {arXiv}, author = {Tristram, Konrad R. W. and Raban, David and Meisenheimer, Klaus and Jaffe, Walter and R\&\#xf6;ttgering, Huub and Burtscher, Leonard and Cotton, William D. and Graser, Uwe and Henning, Thomas and Leinert, Christoph and Lopez, Bruno and Morel, S\&\#xe9;bastien and Perrin, Guy and Wittkowski, Markus}, citeulike-article-id = {4238935}, citeulike-linkout-0 = {http://arxiv.org/abs/0903.4892}, citeulike-linkout-1 = {http://arxiv.org/pdf/0903.4892}, day = {30}, eprint = {0903.4892}, keywords = {agn, midi}, month = {Mar}, posted-at = {2009-03-31 09:21:32}, priority = {2}, title = {Parsec-scale dust distributions in Seyfert galaxies - Results of the MIDI AGN snapshot survey}, url = {http://arxiv.org/abs/0903.4892}, year = {2009} }

TY - JOUR ID - citeulike:4238935 L3 - citeulike-article-id:4238935 N2 - The emission of warm dust dominates the mid-infrared spectra of active galactic nuclei (AGN). Only interferometric observations provide the necessary angular resolution to resolve the nuclear dust and study its distribution and properties. The investigation of dust in AGN cores is hence one of the main science goals for the MID-infrared interferometric Instrument MIDI at the VLTI. In a first step, the feasibility of AGN observations was verified and the most promising sources for detailed studies were identified. To this end, we carried out a "snapshot survey" with MIDI using Guaranteed Time Observations. In the survey, observations were attempted for 13 of the brightest AGN in the mid-infrared, which are visible from Paranal. The results of the three brightest sources have been published in separate papers. Here we present the interferometric observations for the remaining 10, fainter AGN. For 8 of these, interferometric measurements could be carried out. Size estimates or limits on the spatial extent of the AGN-heated dust can be derived from the interferometric data of 7 AGN. These indicate that the dust distributions are compact, with sizes on the order of a few parsec. The derived sizes roughly scale with the square root of the luminosity in the mid-infrared, s ~ sqrt(L), with no clear differences between type 1 and type 2 objects. This is in agreement with nearly optically thick dust structures heated to T ~ 300 K. For several sources, we tentatively detect the 10 micron feature due to silicates either in emission or in absorption. Based on the results for all AGN studied with MIDI so far, it seems that in the mid-infrared the individual differences between galactic nuclei are greater than the generic differences between type 1 and type 2 objects. TI - Parsec-scale dust distributions in Seyfert galaxies - Results of the MIDI AGN snapshot survey KW - agn KW - midi AU - Tristram, Konrad AU - Raban, David AU - Meisenheimer, Klaus AU - Jaffe, Walter AU - Röttgering, Huub AU - Burtscher, Leonard AU - Cotton, William AU - Graser, Uwe AU - Henning, Thomas AU - Leinert, Christoph AU - Lopez, Bruno AU - Morel, Sébastien AU - Perrin, Guy AU - Wittkowski, Markus PY - 2009/Mar/30/ UR - http://arxiv.org/abs/0903.4892 ER -