skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Long-term monitoring of PKS 0537-441 with Fermi-LAT and multiwavelength observations

Abstract

Here, we report on multiwavelength observations of the blazar PKS 0537-441 (z = 0.896) obtained from microwaves through γ-rays by Submillimeter Array, Rapid Eye Mounting, Automatic Telescope for Optical Monitoring (ATOM), Swift and Fermi mostly during 2008 August–2010 April. Strong variability has been observed in γ-rays, with two major flaring episodes (2009 July and 2010 March) and a harder-when-brighter behaviour, quite common for flat spectrum radio quasars and low-synchrotron-peaked BL Lacertae objects (BL Lacs), in 2010 March. In the same way, the spectral energy distribution (SED) of the source cannot be modelled by a simple synchrotron self-Compton model, as opposed to many BL Lacs, but the addition of an external Compton component of seed photons from a dust torus is needed. The 230 GHz light curve showed an increase simultaneous with the γ-ray one, indicating co-spatiality of the mm and γ-ray emission region likely at large distance from the central engine. The low, average, and high activity SED of the source could be fit changing only the electron distribution parameters, but two breaks in the electron distribution are necessary. The ensuing extra spectral break, located at near-infrared (NIR)–optical frequencies, together with that in γ-rays seem to indicate a common origin,more » most likely due to an intrinsic feature in the underlying electron distribution. An overall correlation between the γ-ray band with the R band and K band has been observed with no significant time lag. On the other hand, when inspecting the light curves on short time-scales some differences are evident. In particular, flaring activity has been detected in NIR and optical bands with no evident γ-ray counterparts in 2009 September and November. Moderate variability has been observed in X-rays with no correlation between flux and photon index. Finally, an increase of the detected X-ray flux with no counterpart at the other wavelengths has been observed in 2008 October, suggesting once more a complex correlation between the emission at different energy bands.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »; ; ; ; « less
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
Contributing Org.:
Fermi-LAT Collaboration
OSTI Identifier:
1356593
Grant/Contract Number:  
AC02-76SF00515
Resource Type:
Accepted Manuscript
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Volume: 431; Journal Issue: 3; Journal ID: ISSN 0035-8711
Publisher:
Royal Astronomical Society
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: active; BL Lacertae objects: general; BL Lacertae objects: individual: PKS 0537−441; galaxies: quasars: general

Citation Formats

D'Ammando, F., Antolini, E., Tosti, G., Finke, J., Ciprini, S., Larsson, S., Ajello, M., Covino, S., Gasparrini, D., Gurwell, M., Hauser, M., Romano, P., Schinzel, F., Wagner, S. J., Impiombato, D., Perri, M., Persic, M., Pian, E., Polenta, G., Sbarufatti, B., Treves, A., Vercellone, S., Wehrle, A., and Zook, A. Long-term monitoring of PKS 0537-441 with Fermi-LAT and multiwavelength observations. United States: N. p., 2013. Web. doi:10.1093/mnras/stt344.
D'Ammando, F., Antolini, E., Tosti, G., Finke, J., Ciprini, S., Larsson, S., Ajello, M., Covino, S., Gasparrini, D., Gurwell, M., Hauser, M., Romano, P., Schinzel, F., Wagner, S. J., Impiombato, D., Perri, M., Persic, M., Pian, E., Polenta, G., Sbarufatti, B., Treves, A., Vercellone, S., Wehrle, A., & Zook, A. Long-term monitoring of PKS 0537-441 with Fermi-LAT and multiwavelength observations. United States. doi:10.1093/mnras/stt344.
D'Ammando, F., Antolini, E., Tosti, G., Finke, J., Ciprini, S., Larsson, S., Ajello, M., Covino, S., Gasparrini, D., Gurwell, M., Hauser, M., Romano, P., Schinzel, F., Wagner, S. J., Impiombato, D., Perri, M., Persic, M., Pian, E., Polenta, G., Sbarufatti, B., Treves, A., Vercellone, S., Wehrle, A., and Zook, A. Wed . "Long-term monitoring of PKS 0537-441 with Fermi-LAT and multiwavelength observations". United States. doi:10.1093/mnras/stt344. https://www.osti.gov/servlets/purl/1356593.
@article{osti_1356593,
title = {Long-term monitoring of PKS 0537-441 with Fermi-LAT and multiwavelength observations},
author = {D'Ammando, F. and Antolini, E. and Tosti, G. and Finke, J. and Ciprini, S. and Larsson, S. and Ajello, M. and Covino, S. and Gasparrini, D. and Gurwell, M. and Hauser, M. and Romano, P. and Schinzel, F. and Wagner, S. J. and Impiombato, D. and Perri, M. and Persic, M. and Pian, E. and Polenta, G. and Sbarufatti, B. and Treves, A. and Vercellone, S. and Wehrle, A. and Zook, A.},
abstractNote = {Here, we report on multiwavelength observations of the blazar PKS 0537-441 (z = 0.896) obtained from microwaves through γ-rays by Submillimeter Array, Rapid Eye Mounting, Automatic Telescope for Optical Monitoring (ATOM), Swift and Fermi mostly during 2008 August–2010 April. Strong variability has been observed in γ-rays, with two major flaring episodes (2009 July and 2010 March) and a harder-when-brighter behaviour, quite common for flat spectrum radio quasars and low-synchrotron-peaked BL Lacertae objects (BL Lacs), in 2010 March. In the same way, the spectral energy distribution (SED) of the source cannot be modelled by a simple synchrotron self-Compton model, as opposed to many BL Lacs, but the addition of an external Compton component of seed photons from a dust torus is needed. The 230 GHz light curve showed an increase simultaneous with the γ-ray one, indicating co-spatiality of the mm and γ-ray emission region likely at large distance from the central engine. The low, average, and high activity SED of the source could be fit changing only the electron distribution parameters, but two breaks in the electron distribution are necessary. The ensuing extra spectral break, located at near-infrared (NIR)–optical frequencies, together with that in γ-rays seem to indicate a common origin, most likely due to an intrinsic feature in the underlying electron distribution. An overall correlation between the γ-ray band with the R band and K band has been observed with no significant time lag. On the other hand, when inspecting the light curves on short time-scales some differences are evident. In particular, flaring activity has been detected in NIR and optical bands with no evident γ-ray counterparts in 2009 September and November. Moderate variability has been observed in X-rays with no correlation between flux and photon index. Finally, an increase of the detected X-ray flux with no counterpart at the other wavelengths has been observed in 2008 October, suggesting once more a complex correlation between the emission at different energy bands.},
doi = {10.1093/mnras/stt344},
journal = {Monthly Notices of the Royal Astronomical Society},
number = 3,
volume = 431,
place = {United States},
year = {2013},
month = {3}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 22 works
Citation information provided by
Web of Science

Save / Share: