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Monitoring of the optical and 2.5-11.7 micron spectrum and mid-IR imaging of the Seyfert 1 galaxy Mrk279 with ISO

The AGN Watch collaboration·M. Santos-Lleo·J. Clavel·B. Schulz·B. Altieri·P. Barr·D. Alloin·P. Berlind·R. Bertram·D. M. Crenshaw·R. A. Edelson·U. Giveon·K. Horne·J. P. Huchra·S. Kaspi·G. A. Kriss·J. H. Krolik·M. A. Malkan·Yu. F. Malkov·H. Netzer·P. T. O'Brien·B. M. Peterson
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Abstract

Mid-infrared images of the Seyfert 1 galaxy Mrk 279 obtained with the ISO satellite are presented together with the results of a one-year monitoring campaign of the 2.5-11.7 micron spectrum. Contemporaneous optical photometric and spectrophotometric observations are also presented. The galaxy appears as a point-like source at the resolution of the ISOCAM instrument, 4-5". The 2.5-11.7 micron average spectrum of the nucleus in Mrk 279 shows a strong power law continuum with a spectral index alpha = -0.80+/-0.05 and weak PAH emission features. The Mrk 279 spectral energy distribution shows a mid-IR bump, which extends from 2 to 15-20 micron . The mid-IR bump is consistent with thermal emission from dust grains at a distance of >= 100 light-days. No significant variations of the mid-IR flux have been detected during our observing campaign, consistent with the relatively low amplitude (~10 % rms) of the optical variability during the campaign. The time delay for the Hbeta line emission in response to the optical continuum variations is 16.7 +5.3/5.6 days, consistent with previous measurements.

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The AGN Watch collaboration, M. Santos-Lleo, J. Clavel, B. Schulz, B. Altieri, P. Barr, D. Alloin, P. Berlind, R. Bertram, D. M. Crenshaw, R. A. Edelson, U. Giveon, K. Horne, J. P. Huchra, S. Kaspi, G. A. Kriss, J. H. Krolik, M. A. Malkan, Yu. F. Malkov, H. Netzer, P. T. O'Brien, B. M. Peterson. 2001-02-21. Monitoring of the optical and 2.5-11.7 micron spectrum and mid-IR imaging of the Seyfert 1 galaxy Mrk279 with ISO. https://arxiv.org/abs/astro-ph/0102356

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