Detection of nuclear x-ray sources in nearby galaxies with chandra

Luis C. Ho, Eric D. Feigelson, Leisa K. Townsley, Rita M. Sambruna, Gordon P. Garmire, W. N. Brandt, Alexei V. Filippenko, Richard E. Griffiths, Andrew F. Ptak, Wallace L.W. Sargent

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Abstract

We report preliminary results from an arcsecond-resolution X-ray survey of nearby galaxies using the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory. The total sample consists of 41 low-luminosity active galactic nuclei (AGNs), including Seyfert galaxies, LINERs, and LINER/H II transition objects. In the initial subsample of 24 objects observed thus far, we detect in ∼62% of the objects a compact, pointlike source astrometrically coincident with either the optical or radio position of the nucleus. The high detection rate strongly suggests that the majority of the objects do contain weakly active, AGN-like cores, presumably powered by central massive black holes. The 2-10 keV luminosities of the nuclear sources range from less than 1038 to 1041 ergs s-1, with a median value of 2 × 1038 ergs s-1. Our detection limit corresponds to LX(2-10 keV) ≈ 8 × 1037 ergs s-1 for the typical sample distance of 12 Mpc; this limit is 2 orders of magnitude fainter than the weakest sources of this kind previously studied using ASCA or BeppoSAX. The new data extend toward lower luminosities the known linear correlation between hard X-ray and Hα luminosity for broad-line AGNs. Many narrow-line objects do contain X-ray cores, consistent with either weak AGNs or X-ray binary systems, but they have X-ray luminosities a factor of 10 below the LX-L relation of the broad-line sources. Their distributions of photon energies show no indication of exceptionally high absorption. The optical line emission in these nuclei is likely powered, at least in part, by stellar processes.

Original languageEnglish (US)
Pages (from-to)L51-L54
JournalAstrophysical Journal
Volume549
Issue number1 PART 2
DOIs
StatePublished - Mar 1 2001

Fingerprint

x ray sources
galaxies
active galactic nuclei
luminosity
erg
x rays
nuclei
Seyfert galaxies
imaging spectrometers
detection
charge coupled devices
observatories
indication
spectrometer
observatory
radio
photons
energy

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Ho, Luis C. ; Feigelson, Eric D. ; Townsley, Leisa K. ; Sambruna, Rita M. ; Garmire, Gordon P. ; Brandt, W. N. ; Filippenko, Alexei V. ; Griffiths, Richard E. ; Ptak, Andrew F. ; Sargent, Wallace L.W. / Detection of nuclear x-ray sources in nearby galaxies with chandra. In: Astrophysical Journal. 2001 ; Vol. 549, No. 1 PART 2. pp. L51-L54.
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title = "Detection of nuclear x-ray sources in nearby galaxies with chandra",
abstract = "We report preliminary results from an arcsecond-resolution X-ray survey of nearby galaxies using the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory. The total sample consists of 41 low-luminosity active galactic nuclei (AGNs), including Seyfert galaxies, LINERs, and LINER/H II transition objects. In the initial subsample of 24 objects observed thus far, we detect in ∼62{\%} of the objects a compact, pointlike source astrometrically coincident with either the optical or radio position of the nucleus. The high detection rate strongly suggests that the majority of the objects do contain weakly active, AGN-like cores, presumably powered by central massive black holes. The 2-10 keV luminosities of the nuclear sources range from less than 1038 to 1041 ergs s-1, with a median value of 2 × 1038 ergs s-1. Our detection limit corresponds to LX(2-10 keV) ≈ 8 × 1037 ergs s-1 for the typical sample distance of 12 Mpc; this limit is 2 orders of magnitude fainter than the weakest sources of this kind previously studied using ASCA or BeppoSAX. The new data extend toward lower luminosities the known linear correlation between hard X-ray and Hα luminosity for broad-line AGNs. Many narrow-line objects do contain X-ray cores, consistent with either weak AGNs or X-ray binary systems, but they have X-ray luminosities a factor of 10 below the LX-LHα relation of the broad-line sources. Their distributions of photon energies show no indication of exceptionally high absorption. The optical line emission in these nuclei is likely powered, at least in part, by stellar processes.",
author = "Ho, {Luis C.} and Feigelson, {Eric D.} and Townsley, {Leisa K.} and Sambruna, {Rita M.} and Garmire, {Gordon P.} and Brandt, {W. N.} and Filippenko, {Alexei V.} and Griffiths, {Richard E.} and Ptak, {Andrew F.} and Sargent, {Wallace L.W.}",
year = "2001",
month = "3",
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language = "English (US)",
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Ho, LC, Feigelson, ED, Townsley, LK, Sambruna, RM, Garmire, GP, Brandt, WN, Filippenko, AV, Griffiths, RE, Ptak, AF & Sargent, WLW 2001, 'Detection of nuclear x-ray sources in nearby galaxies with chandra', Astrophysical Journal, vol. 549, no. 1 PART 2, pp. L51-L54. https://doi.org/10.1086/319138

Detection of nuclear x-ray sources in nearby galaxies with chandra. / Ho, Luis C.; Feigelson, Eric D.; Townsley, Leisa K.; Sambruna, Rita M.; Garmire, Gordon P.; Brandt, W. N.; Filippenko, Alexei V.; Griffiths, Richard E.; Ptak, Andrew F.; Sargent, Wallace L.W.

In: Astrophysical Journal, Vol. 549, No. 1 PART 2, 01.03.2001, p. L51-L54.

Research output: Contribution to journalArticle

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T1 - Detection of nuclear x-ray sources in nearby galaxies with chandra

AU - Ho, Luis C.

AU - Feigelson, Eric D.

AU - Townsley, Leisa K.

AU - Sambruna, Rita M.

AU - Garmire, Gordon P.

AU - Brandt, W. N.

AU - Filippenko, Alexei V.

AU - Griffiths, Richard E.

AU - Ptak, Andrew F.

AU - Sargent, Wallace L.W.

PY - 2001/3/1

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N2 - We report preliminary results from an arcsecond-resolution X-ray survey of nearby galaxies using the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory. The total sample consists of 41 low-luminosity active galactic nuclei (AGNs), including Seyfert galaxies, LINERs, and LINER/H II transition objects. In the initial subsample of 24 objects observed thus far, we detect in ∼62% of the objects a compact, pointlike source astrometrically coincident with either the optical or radio position of the nucleus. The high detection rate strongly suggests that the majority of the objects do contain weakly active, AGN-like cores, presumably powered by central massive black holes. The 2-10 keV luminosities of the nuclear sources range from less than 1038 to 1041 ergs s-1, with a median value of 2 × 1038 ergs s-1. Our detection limit corresponds to LX(2-10 keV) ≈ 8 × 1037 ergs s-1 for the typical sample distance of 12 Mpc; this limit is 2 orders of magnitude fainter than the weakest sources of this kind previously studied using ASCA or BeppoSAX. The new data extend toward lower luminosities the known linear correlation between hard X-ray and Hα luminosity for broad-line AGNs. Many narrow-line objects do contain X-ray cores, consistent with either weak AGNs or X-ray binary systems, but they have X-ray luminosities a factor of 10 below the LX-LHα relation of the broad-line sources. Their distributions of photon energies show no indication of exceptionally high absorption. The optical line emission in these nuclei is likely powered, at least in part, by stellar processes.

AB - We report preliminary results from an arcsecond-resolution X-ray survey of nearby galaxies using the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory. The total sample consists of 41 low-luminosity active galactic nuclei (AGNs), including Seyfert galaxies, LINERs, and LINER/H II transition objects. In the initial subsample of 24 objects observed thus far, we detect in ∼62% of the objects a compact, pointlike source astrometrically coincident with either the optical or radio position of the nucleus. The high detection rate strongly suggests that the majority of the objects do contain weakly active, AGN-like cores, presumably powered by central massive black holes. The 2-10 keV luminosities of the nuclear sources range from less than 1038 to 1041 ergs s-1, with a median value of 2 × 1038 ergs s-1. Our detection limit corresponds to LX(2-10 keV) ≈ 8 × 1037 ergs s-1 for the typical sample distance of 12 Mpc; this limit is 2 orders of magnitude fainter than the weakest sources of this kind previously studied using ASCA or BeppoSAX. The new data extend toward lower luminosities the known linear correlation between hard X-ray and Hα luminosity for broad-line AGNs. Many narrow-line objects do contain X-ray cores, consistent with either weak AGNs or X-ray binary systems, but they have X-ray luminosities a factor of 10 below the LX-LHα relation of the broad-line sources. Their distributions of photon energies show no indication of exceptionally high absorption. The optical line emission in these nuclei is likely powered, at least in part, by stellar processes.

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