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

Title: The Origins of the Gamma-Ray Flux Variations of NGC 1275 Based on Eight Years of Fermi-LAT Observations

Abstract

Here, we present an analysis of eight years of Fermi-LAT (>0.1 GeV) γ-ray data obtained for the radio galaxy NGC 1275. The γ-ray flux from NGC 1275 is highly variable on short (~days to weeks) timescales, and has steadily increased over this eight year timespan. By examining the changes in its flux and spectral shape in the LAT energy band over the entire data set, we found that its spectral behavior changed around 2011 February (~MJD 55600). The γ-ray spectra at early times evolved largely at high energies, while the photon indices were unchanged at later times despite rather large flux variations. To explain these observations, we suggest that the flux changes at the early times were caused by injection of high-energy electrons into the jet while, later, the γ-ray flares were caused by a changing Doppler factor owing to variations in the jet Lorentz factor and/or changes in the angle to our line of sight. To demonstrate the viability of these scenarios, we fit the broad band spectral energy distribution data with a one-zone synchrotron self-Compton (SSC) model for flaring and quiescent intervals before and after 2011 February. To explain the γ-ray spectral behavior in the context of themore » SSC model, the maximum electron Lorentz factor would have changed at the early times, while a modest change in the Doppler factor adequately fits the quiescent and flaring state γ-ray spectra at the later times.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2];  [1]; ORCiD logo [3];  [4]; ORCiD logo [5]
  1. Waseda Univ., Tokyo (Japan)
  2. Waseda Univ., Tokyo (Japan); Kanazawa Univ., Ishikawa (Japan)
  3. Naval Research Lab., Washington D.C. (United States)
  4. Stanford Univ., Stanford, CA (United States)
  5. Hiroshima Univ., Hiroshima (Japan)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1460993
Grant/Contract Number:  
AC02-76SF00515
Resource Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 860; Journal Issue: 1; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: active; galaxies: individual (NGC 1275); galaxies: jets; galaxies: Seyfert; gamma rays: general; radiation mechanisms: non-thermal

Citation Formats

Tanada, K., Kataoka, J., Arimoto, M., Akita, M., Cheung, C. C., Digel, S. W., and Fukazawa, Y. The Origins of the Gamma-Ray Flux Variations of NGC 1275 Based on Eight Years of Fermi-LAT Observations. United States: N. p., 2018. Web. doi:10.3847/1538-4357/aac26b.
Tanada, K., Kataoka, J., Arimoto, M., Akita, M., Cheung, C. C., Digel, S. W., & Fukazawa, Y. The Origins of the Gamma-Ray Flux Variations of NGC 1275 Based on Eight Years of Fermi-LAT Observations. United States. doi:10.3847/1538-4357/aac26b.
Tanada, K., Kataoka, J., Arimoto, M., Akita, M., Cheung, C. C., Digel, S. W., and Fukazawa, Y. Sun . "The Origins of the Gamma-Ray Flux Variations of NGC 1275 Based on Eight Years of Fermi-LAT Observations". United States. doi:10.3847/1538-4357/aac26b. https://www.osti.gov/servlets/purl/1460993.
@article{osti_1460993,
title = {The Origins of the Gamma-Ray Flux Variations of NGC 1275 Based on Eight Years of Fermi-LAT Observations},
author = {Tanada, K. and Kataoka, J. and Arimoto, M. and Akita, M. and Cheung, C. C. and Digel, S. W. and Fukazawa, Y.},
abstractNote = {Here, we present an analysis of eight years of Fermi-LAT (>0.1 GeV) γ-ray data obtained for the radio galaxy NGC 1275. The γ-ray flux from NGC 1275 is highly variable on short (~days to weeks) timescales, and has steadily increased over this eight year timespan. By examining the changes in its flux and spectral shape in the LAT energy band over the entire data set, we found that its spectral behavior changed around 2011 February (~MJD 55600). The γ-ray spectra at early times evolved largely at high energies, while the photon indices were unchanged at later times despite rather large flux variations. To explain these observations, we suggest that the flux changes at the early times were caused by injection of high-energy electrons into the jet while, later, the γ-ray flares were caused by a changing Doppler factor owing to variations in the jet Lorentz factor and/or changes in the angle to our line of sight. To demonstrate the viability of these scenarios, we fit the broad band spectral energy distribution data with a one-zone synchrotron self-Compton (SSC) model for flaring and quiescent intervals before and after 2011 February. To explain the γ-ray spectral behavior in the context of the SSC model, the maximum electron Lorentz factor would have changed at the early times, while a modest change in the Doppler factor adequately fits the quiescent and flaring state γ-ray spectra at the later times.},
doi = {10.3847/1538-4357/aac26b},
journal = {The Astrophysical Journal (Online)},
number = 1,
volume = 860,
place = {United States},
year = {2018},
month = {6}
}

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

Citation Metrics:
Cited by: 4 works
Citation information provided by
Web of Science

Figures / Tables:

Figure 1 Figure 1: Fermi-LAT light curve and variation of photon index for NGC 1275 over the time interval from 2008 August - 2016 November in 2-week time-bins. Top panel : changes in the $E$ > 100 MeV flux. The magenta dashed line shows the average flux derived from the 8 yearmore » analysis. Middle panel : changes in the power-law photon index. The magenta dashed line shows the average photon index. Bottom panel : changes in the Test Statistic. According to the differences in the photon index behaviors during the flaring intervals, we have divided the light curve into two time intervals showing a large variation (epoch A) and no significant variation (epoch B). In addition, we defined quiescent and the flaring intervals within each epoch as indicated by dotted and dashed double-headed arrows, respectively. The open and filled diamonds in the middle panel represent the time of the Chandra and NuSTAR observations, respectively.« less

Save / Share:

Works referenced in this record:

FERMI LARGE AREA TELESCOPE THIRD SOURCE CATALOG
journal, June 2015

  • Acero, F.; Ackermann, M.; Ajello, M.
  • The Astrophysical Journal Supplement Series, Vol. 218, Issue 2
  • DOI: 10.1088/0067-0049/218/2/23

Electron Acceleration and Gamma-Ray Emission from Blazars
journal, May 1996

  • Inoue, Susumu; Takahara, Fumio
  • The Astrophysical Journal, Vol. 463
  • DOI: 10.1086/177270

Multiwavelength Variability Study of the Classical BL Lac Object PKS 0735+178 on Timescales Ranging from Decades to Minutes
journal, March 2017

  • Goyal, Arti; Stawarz, Łukasz; Ostrowski, Michał
  • The Astrophysical Journal, Vol. 837, Issue 2
  • DOI: 10.3847/1538-4357/aa6000

Decelerating Flows in TeV Blazars: A Resolution to the BL Lacertae-FR I Unification Problem
journal, August 2003

  • Georganopoulos, Markos; Kazanas, Demosthenes
  • The Astrophysical Journal, Vol. 594, Issue 1
  • DOI: 10.1086/378557

The Expanding Radio Lobe of 3C 84 Revealed by VSOP Observations
journal, April 2006

  • Asada, Keiichi; Kameno, Seiji; Shen, Zhi-Qiang
  • Publications of the Astronomical Society of Japan, Vol. 58, Issue 2
  • DOI: 10.1093/pasj/58.2.261

Internal shocks in the jets of radio-loud quasars
journal, August 2001


Deep observation of the NGC 1275 region with MAGIC: search of diffuse γ -ray emission from cosmic rays in the Perseus cluster
journal, April 2016


Constraints on the Physical Parameters of TeV Blazars
journal, December 1998

  • Tavecchio, Fabrizio; Maraschi, Laura; Ghisellini, Gabriele
  • The Astrophysical Journal, Vol. 509, Issue 2
  • DOI: 10.1086/306526

Relativistic jets and the continuum emission in QSOs
journal, January 1980

  • Marscher, A. P.
  • The Astrophysical Journal, Vol. 235
  • DOI: 10.1086/157642

Four Years of Monitoring Blazar PKS 2155−304 with BeppoSAX : Probing the Dynamics of the Jet
journal, June 2002

  • Zhang, Y. H.; Treves, A.; Celotti, A.
  • The Astrophysical Journal, Vol. 572, Issue 2
  • DOI: 10.1086/340349

γ-RAY SPECTRAL EVOLUTION OF NGC 1275 OBSERVED WITH FERMI LARGE AREA TELESCOPE
journal, April 2010


The 1% Concordance Hubble Constant
journal, October 2014


Discovery of a new subparsec counterjet in NGC 1275: the inclination angle and the environment
journal, November 2016

  • Fujita, Yutaka; Nagai, Hiroshi
  • Monthly Notices of the Royal Astronomical Society: Letters, Vol. 465, Issue 1
  • DOI: 10.1093/mnrasl/slw217

THE NUCLEAR SPECTROSCOPIC TELESCOPE ARRAY ( NuSTAR ) HIGH-ENERGY X-RAY MISSION
journal, May 2013

  • Harrison, Fiona A.; Craig, William W.; Christensen, Finn E.
  • The Astrophysical Journal, Vol. 770, Issue 2
  • DOI: 10.1088/0004-637x/770/2/103

X-Ray and Optical Monitoring of a Gamma-Ray-Emitting Radio Galaxy, NGC 1275
journal, April 2013

  • Yamazaki, Syoko; Fukazawa, Yasushi; Sasada, Mahito
  • Publications of the Astronomical Society of Japan, Vol. 65, Issue 2
  • DOI: 10.1093/pasj/65.2.30

XMM‐Newton Observations of the Perseus Cluster. I. The Temperature and Surface Brightness Structure
journal, June 2003

  • Churazov, E.; Forman, W.; Jones, C.
  • The Astrophysical Journal, Vol. 590, Issue 1
  • DOI: 10.1086/374923

Characteristic X‐Ray Variability of TeV Blazars: Probing the Link between the Jet and the Central Engine
journal, October 2001

  • Kataoka, Jun; Takahashi, Tadayuki; Wagner, Stefan J.
  • The Astrophysical Journal, Vol. 560, Issue 2
  • DOI: 10.1086/322442

A wide Chandra view of the core of the Perseus cluster: A wider view of the Perseus cluster
journal, November 2011


Precession of the super-massive black hole in NGC 1275 (3C 84)?
journal, March 2006


The Likelihood Analysis of EGRET Data
journal, April 1996

  • Mattox, J. R.; Bertsch, D. L.; Chiang, J.
  • The Astrophysical Journal, Vol. 461
  • DOI: 10.1086/177068

Implications of Variability Patterns Observed in TeV Blazars on the Structure of the Inner Jet
journal, February 2003

  • Tanihata, Chiharu; Takahashi, Tadayuki; Kataoka, Jun
  • The Astrophysical Journal, Vol. 584, Issue 1
  • DOI: 10.1086/345522

The M87 jet: internal shocks in a plasma beam?
journal, September 1978


Radio, optical and X-ray nuclei in nearby 3CRR radio galaxies
journal, May 2000


Contemporaneous observations of the radio galaxy NGC 1275 from radio to very high energy γ -rays
journal, March 2014


FERMI DISCOVERY OF GAMMA-RAY EMISSION FROM NGC 1275
journal, June 2009


A non-thermal study of the brightest cluster galaxy NGC 1275 – the Gamma-Radio connection over four decades
journal, June 2014

  • Dutson, K. L.; Edge, A. C.; Hinton, J. A.
  • Monthly Notices of the Royal Astronomical Society, Vol. 442, Issue 3
  • DOI: 10.1093/mnras/stu975

KVN observations reveal multiple γ-ray emission regions in 3C 84?
journal, January 2018

  • Hodgson, Jeffrey A.; Rani, Bindu; Lee, Sang-Sung
  • Monthly Notices of the Royal Astronomical Society, Vol. 475, Issue 1
  • DOI: 10.1093/mnras/stx3041

The Jet‐Disk Connection and Blazar Unification
journal, August 2003

  • Maraschi, Laura; Tavecchio, Fabrizio
  • The Astrophysical Journal, Vol. 593, Issue 2
  • DOI: 10.1086/342118

FERMI LARGE AREA TELESCOPE OBSERVATIONS OF MISALIGNED ACTIVE GALACTIC NUCLEI
journal, August 2010


Mojave: Monitoring of jets in Active Galactic Nuclei with vlba Experiments. vi. Kinematics Analysis of a Complete Sample of Blazar jets
journal, November 2009


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


High-energy γ-ray properties of the Fanaroff-Riley type I radio galaxy NGC 1275: High-energy γ-ray properties of the FR I radio galaxy NGC 1275
journal, March 2011


VLBI and single-dish monitoring of 3C 84 for the period 2009-2011: Radio monitoring of 3C 84
journal, May 2012


TeV Gamma‐Ray Observations of the Perseus and Abell 2029 Galaxy Clusters
journal, June 2006

  • Perkins, J. S.; Badran, H. M.; Blaylock, G.
  • The Astrophysical Journal, Vol. 644, Issue 1
  • DOI: 10.1086/503321

EXPLORING THE CENTRAL SUB-PARSEC REGION OF THE γ-RAY BRIGHT RADIO GALAXY 3C 84 WITH VLBA AT 43 GHz IN THE PERIOD OF 2002-2008
journal, February 2012


TeV BL Lac objects at the dawn of the Fermi era
journal, January 2010


Discovery of a nuclear counterjet in NGC 1275: A new way to probe the parsec-scale environment
journal, July 1994

  • Vermeulen, R. C.; Readhead, A. C. S.; Backer, D. C.
  • The Astrophysical Journal, Vol. 430
  • DOI: 10.1086/187433

Detection of a VLBI counterjet in NGC 1275: A possible probe of the parsec-scale accretion region
journal, July 1994

  • Walker, R. C.; Romney, J. D.; Benson, J. M.
  • The Astrophysical Journal, Vol. 430
  • DOI: 10.1086/187434

THE FERMI LARGE AREA TELESCOPE ON ORBIT: EVENT CLASSIFICATION, INSTRUMENT RESPONSE FUNCTIONS, AND CALIBRATION
journal, October 2012

  • Ackermann, M.; Ajello, M.; Albert, A.
  • The Astrophysical Journal Supplement Series, Vol. 203, Issue 1
  • DOI: 10.1088/0067-0049/203/1/4

GALAXY CLUSTERS IN THE SWIFT /BURST ALERT TELESCOPE ERA: HARD X-RAYS IN THE INTRACLUSTER MEDIUM
journal, December 2008


FERMI DISCOVERY OF GAMMA-RAY EMISSION FROM NGC 1275
journal, June 2009


FERMI LARGE AREA TELESCOPE OBSERVATIONS OF MISALIGNED ACTIVE GALACTIC NUCLEI
journal, August 2010


GALAXY CLUSTERS IN THE SWIFT /BURST ALERT TELESCOPE ERA: HARD X-RAYS IN THE INTRACLUSTER MEDIUM
journal, December 2008


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


The 1% Concordance Hubble Constant
journal, October 2014


THE NUCLEAR SPECTROSCOPIC TELESCOPE ARRAY ( NuSTAR ) HIGH-ENERGY X-RAY MISSION
journal, May 2013

  • Harrison, Fiona A.; Craig, William W.; Christensen, Finn E.
  • The Astrophysical Journal, Vol. 770, Issue 2
  • DOI: 10.1088/0004-637X/770/2/103

γ-RAY SPECTRAL EVOLUTION OF NGC 1275 OBSERVED WITH FERMI LARGE AREA TELESCOPE
journal, April 2010


The M87 jet: internal shocks in a plasma beam?
journal, September 1978


EXPLORING THE CENTRAL SUB-PARSEC REGION OF THE γ-RAY BRIGHT RADIO GALAXY 3C 84 WITH VLBA AT 43 GHz IN THE PERIOD OF 2002-2008
journal, February 2012


    Works referencing / citing this record:

    Two Blobs in a Jet Model for the γ -Ray Emission in Radio Galaxies
    journal, September 2018


    Inverse Compton Scattering of Starlight in the Kiloparsec-scale Jet in Centaurus A: The Origin of Excess TeV γ -Ray Emission
    journal, June 2019


    Gamma-ray observations of low-luminosity active galactic nuclei
    journal, January 2020

    • de Menezes, Raniere; Nemmen, Rodrigo; Finke, Justin D.
    • Monthly Notices of the Royal Astronomical Society, Vol. 492, Issue 3
    • DOI: 10.1093/mnras/staa083

    NuStar View of the Central Region of the Perseus Cluster
    journal, October 2018

    • Rani, B.; Madejski, G. M.; Mushotzky, R. F.
    • The Astrophysical Journal, Vol. 866, Issue 1
    • DOI: 10.3847/2041-8213/aae48f

    Analysis of the Spatially Resolved V −3.6 μ m Colors and Dust Extinction in 257 Nearby NGC and IC Galaxies
    journal, October 2019

    • Kim, Duho; Jansen, Rolf A.; Windhorst, Rogier A.
    • The Astrophysical Journal, Vol. 884, Issue 1
    • DOI: 10.3847/1538-4357/ab385c

    Faint γ-ray sources at low redshift: the radio galaxy IC 1531
    journal, September 2018

    • Bassi, T.; Migliori, G.; Grandi, P.
    • Monthly Notices of the Royal Astronomical Society, Vol. 481, Issue 4
    • DOI: 10.1093/mnras/sty2622

    Intra-night optical variability of misaligned active galaxies
    journal, December 2018

    • Bhattacharya, Debbijoy; Gulati, Sanna; Stalin, C. S.
    • Monthly Notices of the Royal Astronomical Society, Vol. 483, Issue 3
    • DOI: 10.1093/mnras/sty3299

    3C 84: Observational Evidence for Precession and a Possible Relation to TeV Emission
    journal, August 2019