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Title: Near-infrared and gamma-ray monitoring of TANAMI gamma-ray bright sources

Abstract

Context. We present that spectral energy distribution and its variability are basic tools for understanding the physical processes operating in active galactic nuclei (AGN). Aims. In this paper we report the results of a one-year near-infrared (NIR) and optical monitoring of a sample of 22 AGN known to be gamma-ray emitters, aimed at discovering correlations between optical and gamma-ray emission. Methods. We observed our objects with the Rapid Eye Mount (REM) telescope in J,H,K, and R bands nearly twice every month during their visibility window and derived light curves and spectral indexes. We also analyzed the gamma-ray data from the Fermi gamma-ray Space Telescope, making weekly averages. Results. Six sources were never detected during our monitoring, proving to be fainter than their historical Two micron all sky survey (2MASS) level. All of the sixteen detected sources showed marked flux density variability, while the spectral indexes remained unchanged within our sensitivity limits. Steeper sources showed, on average, a larger variability. From the NIR light curves we also computed a variability speed index for each detected source. Only one source (PKS 0208-512) underwent an NIR flare during our monitoring. Half of the sources showed a regular flux density trend on a one-yearmore » time scale, but do not show any other peculiar characteristic. The broadband spectral index αro appears to be a good proxy of the NIR spectral index only for BL Lac objects. No clear correlation between NIR and gamma-ray data is evident in our data, save for PKS 0537-441, PKS 0521-360, PKS 2155-304, and PKS 1424-418. In conclusion, the gamma-ray/NIR flux ratio showed a large spread, QSO being generally gamma-louder than BL Lac, with a marked correlation with the estimated peak frequency (νpeak) of the synchrotron emission.« less

Authors:
 [1];  [2];  [3];  [4];  [5]
  1. INAF-IAPS, via Fosso del Cavaliere 100, Roma (Italy); Universita La Sapienza, Roma (Italy)
  2. Universita di Perugia (Italy)
  3. Nordic Optical Telescope (Spain)
  4. NASA Goddard Space Flight Center, Astrophysics Science Division, Greenbelt, MD (United States); Catholic University of America, Washington, DC (United States). Institute for Astrophysics & Computational Sciences
  5. Univ. Wurzburg (Germany). Institut fur Theoretische Physik und Astrophysik, Lehrstuhl fur Astronomie; Dr. Karl-Remeis-Sternwarte and Erlangen Centre for Astroparticle Physics (Germany)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
Contributing Org.:
Fermi-LAT Collaboration
OSTI Identifier:
1356584
Grant/Contract Number:  
AC02-76SF00515
Resource Type:
Accepted Manuscript
Journal Name:
Astronomy and Astrophysics
Additional Journal Information:
Journal Volume: 555; Journal ID: ISSN 0004-6361
Publisher:
EDP Sciences
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; BL Lacertae objects: general; radiation mechanisms: non-thermal; gamma rays: galaxies

Citation Formats

Nesci, R., Tosti, G., Pursimo, T., Ojha, R., and Kadler, M. Near-infrared and gamma-ray monitoring of TANAMI gamma-ray bright sources. United States: N. p., 2013. Web. doi:10.1051/0004-6361/201321094.
Nesci, R., Tosti, G., Pursimo, T., Ojha, R., & Kadler, M. Near-infrared and gamma-ray monitoring of TANAMI gamma-ray bright sources. United States. doi:10.1051/0004-6361/201321094.
Nesci, R., Tosti, G., Pursimo, T., Ojha, R., and Kadler, M. Tue . "Near-infrared and gamma-ray monitoring of TANAMI gamma-ray bright sources". United States. doi:10.1051/0004-6361/201321094. https://www.osti.gov/servlets/purl/1356584.
@article{osti_1356584,
title = {Near-infrared and gamma-ray monitoring of TANAMI gamma-ray bright sources},
author = {Nesci, R. and Tosti, G. and Pursimo, T. and Ojha, R. and Kadler, M.},
abstractNote = {Context. We present that spectral energy distribution and its variability are basic tools for understanding the physical processes operating in active galactic nuclei (AGN). Aims. In this paper we report the results of a one-year near-infrared (NIR) and optical monitoring of a sample of 22 AGN known to be gamma-ray emitters, aimed at discovering correlations between optical and gamma-ray emission. Methods. We observed our objects with the Rapid Eye Mount (REM) telescope in J,H,K, and R bands nearly twice every month during their visibility window and derived light curves and spectral indexes. We also analyzed the gamma-ray data from the Fermi gamma-ray Space Telescope, making weekly averages. Results. Six sources were never detected during our monitoring, proving to be fainter than their historical Two micron all sky survey (2MASS) level. All of the sixteen detected sources showed marked flux density variability, while the spectral indexes remained unchanged within our sensitivity limits. Steeper sources showed, on average, a larger variability. From the NIR light curves we also computed a variability speed index for each detected source. Only one source (PKS 0208-512) underwent an NIR flare during our monitoring. Half of the sources showed a regular flux density trend on a one-year time scale, but do not show any other peculiar characteristic. The broadband spectral index αro appears to be a good proxy of the NIR spectral index only for BL Lac objects. No clear correlation between NIR and gamma-ray data is evident in our data, save for PKS 0537-441, PKS 0521-360, PKS 2155-304, and PKS 1424-418. In conclusion, the gamma-ray/NIR flux ratio showed a large spread, QSO being generally gamma-louder than BL Lac, with a marked correlation with the estimated peak frequency (νpeak) of the synchrotron emission.},
doi = {10.1051/0004-6361/201321094},
journal = {Astronomy and Astrophysics},
number = ,
volume = 555,
place = {United States},
year = {2013},
month = {6}
}

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Works referenced in this record:

FERMI LARGE AREA TELESCOPE SECOND SOURCE CATALOG
journal, March 2012

  • Nolan, P. L.; Abdo, A. A.; Ackermann, M.
  • The Astrophysical Journal Supplement Series, Vol. 199, Issue 2
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THE LARGE AREA TELESCOPE ON THE FERMI GAMMA-RAY SPACE TELESCOPE MISSION
journal, May 2009


Relativistic jets as X-ray and gamma-ray sources
journal, February 1981


Smarts Optical and Infrared Monitoring of 12 Gamma-Ray Bright Blazars
journal, August 2012


A Search for Intraday Variability in the Blazar PKS 2005-489
journal, July 2003

  • Rector, Travis A.; Perlman, Eric S.
  • The Astronomical Journal, Vol. 126, Issue 1
  • DOI: 10.1086/375644

Infrared Colors of the Gamma-Ray-Detected Blazars
journal, March 2012


UBVRI photoelectric photometry in the fields of fifteen active galaxies
journal, March 1989

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The connection between x-ray- and radio-selected BL Lacertae objects
journal, May 1995

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Relativistic jets as compact radio sources
journal, August 1979

  • Blandford, R. D.; Konigl, A.
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TANAMI: tracking active galactic nuclei with austral milliarcsecond interferometry: I. First-epoch 8.4 GHz images
journal, September 2010


Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds
journal, June 1998

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  • The Astrophysical Journal, Vol. 500, Issue 2
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Modeling the Production of Flares in Gamma‐Ray Quasars
journal, June 2001

  • Sikora, M.; Błażejowski, M.; Begelman, Mitchell C.
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  • DOI: 10.1086/321329

GAMMA-RAY LIGHT CURVES AND VARIABILITY OF BRIGHT FERMI -DETECTED BLAZARS
journal, September 2010


SIMILARITY OF THE OPTICAL-INFRARED AND γ-RAY TIME VARIABILITY OF FERMI BLAZARS
journal, April 2012


THE SECOND CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE
journal, December 2011


Roma-BZCAT: a multifrequency catalogue of blazars
journal, December 2008


A test for partial correlation with censored astronomical data
journal, February 1996

  • Akritas, M. G.; Siebert, J.
  • Monthly Notices of the Royal Astronomical Society, Vol. 278, Issue 4
  • DOI: 10.1093/mnras/278.4.919

The Second-Generation Guide star Catalog: Description and Properties
journal, July 2008


THE SPECTRAL ENERGY DISTRIBUTION OF FERMI BRIGHT BLAZARS
journal, May 2010


The classification of BL Lacertae objects: the Ca H&K break
journal, November 2002


Atlas of quasar energy distributions
journal, November 1994

  • Elvis, Martin; Wilkes, Belinda J.; McDowell, Jonathan C.
  • The Astrophysical Journal Supplement Series, Vol. 95
  • DOI: 10.1086/192093

High-energy neutrinos from extragalactic jets
journal, May 1995


Emission lines and optical continuum in low-luminosity radio galaxies
journal, January 2004


TANAMI: Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry: II. Additional sources
journal, February 2018


    Works referencing / citing this record:

    High-energy neutrinos from extragalactic jets
    journal, May 1995


    The classification of BL Lacertae objects: the Ca H&K break
    journal, November 2002


    TANAMI: tracking active galactic nuclei with austral milliarcsecond interferometry: I. First-epoch 8.4 GHz images
    journal, September 2010


    Roma-BZCAT: a multifrequency catalogue of blazars
    journal, December 2008


    UBVRI photoelectric photometry in the fields of fifteen active galaxies
    journal, March 1989

    • Hamuy, Mario; Maza, Jose
    • The Astronomical Journal, Vol. 97
    • DOI: 10.1086/115017

    Relativistic jets as compact radio sources
    journal, August 1979

    • Blandford, R. D.; Konigl, A.
    • The Astrophysical Journal, Vol. 232
    • DOI: 10.1086/157262

    Relativistic jets as X-ray and gamma-ray sources
    journal, February 1981


    The connection between x-ray- and radio-selected BL Lacertae objects
    journal, May 1995

    • Padovani, Paolo; Giommi, Paolo
    • The Astrophysical Journal, Vol. 444
    • DOI: 10.1086/175631

    Atlas of quasar energy distributions
    journal, November 1994

    • Elvis, Martin; Wilkes, Belinda J.; McDowell, Jonathan C.
    • The Astrophysical Journal Supplement Series, Vol. 95
    • DOI: 10.1086/192093

    Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds
    journal, June 1998

    • Schlegel, David J.; Finkbeiner, Douglas P.; Davis, Marc
    • The Astrophysical Journal, Vol. 500, Issue 2
    • DOI: 10.1086/305772

    Modeling the Production of Flares in Gamma‐Ray Quasars
    journal, June 2001

    • Sikora, M.; Błażejowski, M.; Begelman, Mitchell C.
    • The Astrophysical Journal, Vol. 554, Issue 1
    • DOI: 10.1086/321329

    A Search for Intraday Variability in the Blazar PKS 2005-489
    journal, July 2003

    • Rector, Travis A.; Perlman, Eric S.
    • The Astronomical Journal, Vol. 126, Issue 1
    • DOI: 10.1086/375644

    The Second-Generation Guide star Catalog: Description and Properties
    journal, July 2008


    THE LARGE AREA TELESCOPE ON THE FERMI GAMMA-RAY SPACE TELESCOPE MISSION
    journal, May 2009


    THE SPECTRAL ENERGY DISTRIBUTION OF FERMI BRIGHT BLAZARS
    journal, May 2010


    GAMMA-RAY LIGHT CURVES AND VARIABILITY OF BRIGHT FERMI -DETECTED BLAZARS
    journal, September 2010


    THE SECOND CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE
    journal, December 2011


    Infrared Colors of the Gamma-Ray-Detected Blazars
    journal, March 2012


    SIMILARITY OF THE OPTICAL-INFRARED AND γ-RAY TIME VARIABILITY OF FERMI BLAZARS
    journal, April 2012


    Smarts Optical and Infrared Monitoring of 12 Gamma-Ray Bright Blazars
    journal, August 2012


    FERMI LARGE AREA TELESCOPE SECOND SOURCE CATALOG
    journal, March 2012

    • Nolan, P. L.; Abdo, A. A.; Ackermann, M.
    • The Astrophysical Journal Supplement Series, Vol. 199, Issue 2
    • DOI: 10.1088/0067-0049/199/2/31

    A test for partial correlation with censored astronomical data
    journal, February 1996

    • Akritas, M. G.; Siebert, J.
    • Monthly Notices of the Royal Astronomical Society, Vol. 278, Issue 4
    • DOI: 10.1093/mnras/278.4.919

    Emission lines and optical continuum in low-luminosity radio galaxies
    journal, January 2004


    H.E.S.S. discovery of very high energy γ-ray emission from PKS 0625−354
    journal, February 2018

    • Abdalla, H.; Abramowski, A.; Aharonian, F.
    • Monthly Notices of the Royal Astronomical Society, Vol. 476, Issue 3
    • DOI: 10.1093/mnras/sty439