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Title: Radio-to- γ-ray monitoring of the narrow-line Seyfert 1 galaxy PMN J0948 + 0022 from 2008 to 2011

Abstract

Here, we present more than three years of observations at different frequencies, from radio to high-energy γ-rays, of the Narrow-Line Seyfert 1 (NLS1) Galaxy PMN J0948 + 0022 (z = 0.585). This source is the first NLS1 detected at energies above 100 MeV and therefore can be considered the prototype of this emerging new class of γ-ray emitting active galactic nuclei (AGN). The observations performed from 2008 August 1 to 2011 December 31 confirmed that PMN J0948 + 0022 generates a powerful relativistic jet, which is able to develop an isotropic luminosity at γ-rays of the order of 10 48 erg s -1, at the level of powerful quasars. The evolution of the radiation emission of this source in 2009 and 2010 followed the canonical expectations of relativistic jets with correlated multiwavelength variability (γ-rays followed by radio emission after a few months), but it was difficult to retrieve a similar pattern in the light curves of 2011. The comparison of γ-ray spectra before and including 2011 data suggested that there was a softening of the high-energy spectral slope. We selected five specific epochs to be studied by modelling the broad-band spectrum, which are characterised by an outburst at γ-rays ormore » very low/high flux at other wavelengths. The observed variability can largely be explained by changes in the injected power, the bulk Lorentz factor of the jet, or the electron spectrum. The characteristic time scale of doubling/halving flux ranges from a few days to a few months, depending on the frequency and the sampling rate. The shortest doubling time scale at γ-rays is 2.3 ± 0.5 days. Finally, these small values underline the need of highly sampled multiwavelength campaigns to better understand the physics of these sources.« less

Authors:
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Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
Contributing Org.:
Fermi-LAT Collaboration
OSTI Identifier:
1356605
Grant/Contract Number:  
AC02-76SF00515
Resource Type:
Accepted Manuscript
Journal Name:
Astronomy and Astrophysics
Additional Journal Information:
Journal Volume: 548; Journal ID: ISSN 0004-6361
Publisher:
EDP Sciences
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: jets; galaxies: Seyfert; gamma rays: galaxies; galaxies: individual: PMN J0948+0022

Citation Formats

Foschini, L., Angelakis, E., Fuhrmann, L., Ghisellini, G., Hovatta, T., Lahteenmaki, A., Lister, M. L., Braito, V., Gallo, L., Hamilton, T. S., Kino, M., Komossa, S., Pushkarev, A. B., Thompson, D. J., Tibolla, O., Tramacere, A., Carramiñana, A., Carrasco, L., Falcone, A., Giroletti, M., Grupe, D., Kovalev, Y. Y., Krichbaum, T. P., Max-Moerbeck, W., Nestoras, I., Pearson, T. J., Porras, A., Readhead, A. C. S., Recillas, E., Richards, J. L., Riquelme, D., Sievers, A., Tammi, J., Tornikoski, M., Ungerechts, H., Zensus, J. A., Celotti, A., Bonnoli, G., Doi, A., Maraschi, L., Tagliaferri, G., and Tavecchio, F. Radio-to-γ-ray monitoring of the narrow-line Seyfert 1 galaxy PMN J0948 + 0022 from 2008 to 2011. United States: N. p., 2012. Web. doi:10.1051/0004-6361/201220225.
Foschini, L., Angelakis, E., Fuhrmann, L., Ghisellini, G., Hovatta, T., Lahteenmaki, A., Lister, M. L., Braito, V., Gallo, L., Hamilton, T. S., Kino, M., Komossa, S., Pushkarev, A. B., Thompson, D. J., Tibolla, O., Tramacere, A., Carramiñana, A., Carrasco, L., Falcone, A., Giroletti, M., Grupe, D., Kovalev, Y. Y., Krichbaum, T. P., Max-Moerbeck, W., Nestoras, I., Pearson, T. J., Porras, A., Readhead, A. C. S., Recillas, E., Richards, J. L., Riquelme, D., Sievers, A., Tammi, J., Tornikoski, M., Ungerechts, H., Zensus, J. A., Celotti, A., Bonnoli, G., Doi, A., Maraschi, L., Tagliaferri, G., & Tavecchio, F. Radio-to-γ-ray monitoring of the narrow-line Seyfert 1 galaxy PMN J0948 + 0022 from 2008 to 2011. United States. doi:10.1051/0004-6361/201220225.
Foschini, L., Angelakis, E., Fuhrmann, L., Ghisellini, G., Hovatta, T., Lahteenmaki, A., Lister, M. L., Braito, V., Gallo, L., Hamilton, T. S., Kino, M., Komossa, S., Pushkarev, A. B., Thompson, D. J., Tibolla, O., Tramacere, A., Carramiñana, A., Carrasco, L., Falcone, A., Giroletti, M., Grupe, D., Kovalev, Y. Y., Krichbaum, T. P., Max-Moerbeck, W., Nestoras, I., Pearson, T. J., Porras, A., Readhead, A. C. S., Recillas, E., Richards, J. L., Riquelme, D., Sievers, A., Tammi, J., Tornikoski, M., Ungerechts, H., Zensus, J. A., Celotti, A., Bonnoli, G., Doi, A., Maraschi, L., Tagliaferri, G., and Tavecchio, F. Fri . "Radio-to-γ-ray monitoring of the narrow-line Seyfert 1 galaxy PMN J0948 + 0022 from 2008 to 2011". United States. doi:10.1051/0004-6361/201220225. https://www.osti.gov/servlets/purl/1356605.
@article{osti_1356605,
title = {Radio-to-γ-ray monitoring of the narrow-line Seyfert 1 galaxy PMN J0948 + 0022 from 2008 to 2011},
author = {Foschini, L. and Angelakis, E. and Fuhrmann, L. and Ghisellini, G. and Hovatta, T. and Lahteenmaki, A. and Lister, M. L. and Braito, V. and Gallo, L. and Hamilton, T. S. and Kino, M. and Komossa, S. and Pushkarev, A. B. and Thompson, D. J. and Tibolla, O. and Tramacere, A. and Carramiñana, A. and Carrasco, L. and Falcone, A. and Giroletti, M. and Grupe, D. and Kovalev, Y. Y. and Krichbaum, T. P. and Max-Moerbeck, W. and Nestoras, I. and Pearson, T. J. and Porras, A. and Readhead, A. C. S. and Recillas, E. and Richards, J. L. and Riquelme, D. and Sievers, A. and Tammi, J. and Tornikoski, M. and Ungerechts, H. and Zensus, J. A. and Celotti, A. and Bonnoli, G. and Doi, A. and Maraschi, L. and Tagliaferri, G. and Tavecchio, F.},
abstractNote = {Here, we present more than three years of observations at different frequencies, from radio to high-energy γ-rays, of the Narrow-Line Seyfert 1 (NLS1) Galaxy PMN J0948 + 0022 (z = 0.585). This source is the first NLS1 detected at energies above 100 MeV and therefore can be considered the prototype of this emerging new class of γ-ray emitting active galactic nuclei (AGN). The observations performed from 2008 August 1 to 2011 December 31 confirmed that PMN J0948 + 0022 generates a powerful relativistic jet, which is able to develop an isotropic luminosity at γ-rays of the order of 1048 erg s-1, at the level of powerful quasars. The evolution of the radiation emission of this source in 2009 and 2010 followed the canonical expectations of relativistic jets with correlated multiwavelength variability (γ-rays followed by radio emission after a few months), but it was difficult to retrieve a similar pattern in the light curves of 2011. The comparison of γ-ray spectra before and including 2011 data suggested that there was a softening of the high-energy spectral slope. We selected five specific epochs to be studied by modelling the broad-band spectrum, which are characterised by an outburst at γ-rays or very low/high flux at other wavelengths. The observed variability can largely be explained by changes in the injected power, the bulk Lorentz factor of the jet, or the electron spectrum. The characteristic time scale of doubling/halving flux ranges from a few days to a few months, depending on the frequency and the sampling rate. The shortest doubling time scale at γ-rays is 2.3 ± 0.5 days. Finally, these small values underline the need of highly sampled multiwavelength campaigns to better understand the physics of these sources.},
doi = {10.1051/0004-6361/201220225},
journal = {Astronomy and Astrophysics},
number = ,
volume = 548,
place = {United States},
year = {2012},
month = {11}
}

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