41 Citations (Scopus)

Abstract

We report on the X-ray properties of the radio galaxy NGC 4261, combining information from the XMM-Newton, Chandra, and BeppoSAX satellites. Goals of this study are to investigate the origin of the X-rays from this low-power radio galaxy and the nature of the accretion process onto the central black hole. The X-ray spectrum of the nuclear source extending up to 100-150 keV is well described by a partially covered (covering factor >0.8) power law with a photon index Γ ≃ 1.5 absorbed by a column density NH > 5 × 1022 cm-2. The X-ray luminosity associated with the non-thermal components is ∼5 × 1041 erg s-1. The nuclear source is embedded in a diffuse hot gas (kT ∼ 0.6-0.65 keV), whose density profile implies a Bondi accretion rate of ∼4.5 × 10-2 M⊙ yr-1. For the first time rapid X-ray variability is detected in a low-power radio galaxy at more than 99% confidence level. The observed X-ray spectral and variability properties indicate the accretion flow as the most likely origin of the bulk X-ray continuum. This conclusion is strengthened by energetic considerations based on a comparison between the X-ray luminosity and the kinetic power of the jet, which also suggest that the Bondi accretion rate overestimates the actual accretion rate onto the black hole.

Original languageEnglish (US)
Pages (from-to)949-959
Number of pages11
JournalAstronomy and Astrophysics
Volume408
Issue number3
DOIs
StatePublished - Sep 1 2003

Fingerprint

accretion
radio galaxies
x rays
radio
luminosity
high temperature gases
XMM-Newton telescope
erg
newton
confidence
power law
coverings
energetics
continuums
kinetics
photons
profiles
gas
rate

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

@article{fa9e15d91aa64b219f57360faf888f94,
title = "On the origin of the X-rays and the nature of accretion in NGC 4261",
abstract = "We report on the X-ray properties of the radio galaxy NGC 4261, combining information from the XMM-Newton, Chandra, and BeppoSAX satellites. Goals of this study are to investigate the origin of the X-rays from this low-power radio galaxy and the nature of the accretion process onto the central black hole. The X-ray spectrum of the nuclear source extending up to 100-150 keV is well described by a partially covered (covering factor >0.8) power law with a photon index Γ ≃ 1.5 absorbed by a column density NH > 5 × 1022 cm-2. The X-ray luminosity associated with the non-thermal components is ∼5 × 1041 erg s-1. The nuclear source is embedded in a diffuse hot gas (kT ∼ 0.6-0.65 keV), whose density profile implies a Bondi accretion rate of ∼4.5 × 10-2 M⊙ yr-1. For the first time rapid X-ray variability is detected in a low-power radio galaxy at more than 99{\%} confidence level. The observed X-ray spectral and variability properties indicate the accretion flow as the most likely origin of the bulk X-ray continuum. This conclusion is strengthened by energetic considerations based on a comparison between the X-ray luminosity and the kinetic power of the jet, which also suggest that the Bondi accretion rate overestimates the actual accretion rate onto the black hole.",
author = "M. Gliozzi and Sambruna, {R. M.} and Brandt, {William Nielsen}",
year = "2003",
month = "9",
day = "1",
doi = "10.1051/0004-6361:20031050",
language = "English (US)",
volume = "408",
pages = "949--959",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",
number = "3",

}

On the origin of the X-rays and the nature of accretion in NGC 4261. / Gliozzi, M.; Sambruna, R. M.; Brandt, William Nielsen.

In: Astronomy and Astrophysics, Vol. 408, No. 3, 01.09.2003, p. 949-959.

Research output: Contribution to journalArticle

TY - JOUR

T1 - On the origin of the X-rays and the nature of accretion in NGC 4261

AU - Gliozzi, M.

AU - Sambruna, R. M.

AU - Brandt, William Nielsen

PY - 2003/9/1

Y1 - 2003/9/1

N2 - We report on the X-ray properties of the radio galaxy NGC 4261, combining information from the XMM-Newton, Chandra, and BeppoSAX satellites. Goals of this study are to investigate the origin of the X-rays from this low-power radio galaxy and the nature of the accretion process onto the central black hole. The X-ray spectrum of the nuclear source extending up to 100-150 keV is well described by a partially covered (covering factor >0.8) power law with a photon index Γ ≃ 1.5 absorbed by a column density NH > 5 × 1022 cm-2. The X-ray luminosity associated with the non-thermal components is ∼5 × 1041 erg s-1. The nuclear source is embedded in a diffuse hot gas (kT ∼ 0.6-0.65 keV), whose density profile implies a Bondi accretion rate of ∼4.5 × 10-2 M⊙ yr-1. For the first time rapid X-ray variability is detected in a low-power radio galaxy at more than 99% confidence level. The observed X-ray spectral and variability properties indicate the accretion flow as the most likely origin of the bulk X-ray continuum. This conclusion is strengthened by energetic considerations based on a comparison between the X-ray luminosity and the kinetic power of the jet, which also suggest that the Bondi accretion rate overestimates the actual accretion rate onto the black hole.

AB - We report on the X-ray properties of the radio galaxy NGC 4261, combining information from the XMM-Newton, Chandra, and BeppoSAX satellites. Goals of this study are to investigate the origin of the X-rays from this low-power radio galaxy and the nature of the accretion process onto the central black hole. The X-ray spectrum of the nuclear source extending up to 100-150 keV is well described by a partially covered (covering factor >0.8) power law with a photon index Γ ≃ 1.5 absorbed by a column density NH > 5 × 1022 cm-2. The X-ray luminosity associated with the non-thermal components is ∼5 × 1041 erg s-1. The nuclear source is embedded in a diffuse hot gas (kT ∼ 0.6-0.65 keV), whose density profile implies a Bondi accretion rate of ∼4.5 × 10-2 M⊙ yr-1. For the first time rapid X-ray variability is detected in a low-power radio galaxy at more than 99% confidence level. The observed X-ray spectral and variability properties indicate the accretion flow as the most likely origin of the bulk X-ray continuum. This conclusion is strengthened by energetic considerations based on a comparison between the X-ray luminosity and the kinetic power of the jet, which also suggest that the Bondi accretion rate overestimates the actual accretion rate onto the black hole.

UR - http://www.scopus.com/inward/record.url?scp=0141592387&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0141592387&partnerID=8YFLogxK

U2 - 10.1051/0004-6361:20031050

DO - 10.1051/0004-6361:20031050

M3 - Article

AN - SCOPUS:0141592387

VL - 408

SP - 949

EP - 959

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

IS - 3

ER -