The contribution of narrow-line Seyfert 1 galaxies to the soft X-ray background

G. Hasinger, I. Lehmann, M. Schmidt, J. E. Gunn, D. P. Schneider, R. Giacconi, J. Trümper, G. Zamorani

Research output: Contribution to journalReview article

6 Citations (Scopus)

Abstract

The ROSAT Ultradeep HRI survey in the Lockman Hole contains a complete sample of 91 X-ray sources with fluxes in the 0.5-2 keV band larger than 1.2×10-15 erg cm-2 s-1, where over 75% of the sources are quasars or Seyfert galaxies. During the course of our optical identification work, we have obtained optical spectra of 67 narrow emission line galaxies (NELG), which are physically not associated with the X-ray sources. We have derived the equivalent width (EW) and the full width at half maximum (FWHM) for the most prominent emission lines of 41 quasars and Seyfert galaxies taken from the ROSAT Deep Survey (RDS), which has a flux limit of 5.5×10-15 erg cm-2 s-1 in the 0.5-2.0 keV band. Furthermore, we have obtained the EW and FWHM values of the field NELGs. Here, we present the spectroscopic discrimination between RDS Seyfert galaxies and field galaxies (NELG). The analysis of the emission lines has revealed that a single object out of 69 spectroscopically identified AGN fits the optical criteria of narrow-line Seyfert 1 galaxies (NLS1). This may indicate that NLS1 contribute only marginally to the soft X-ray background, but we can not exclude a possible larger contribution.

Original languageEnglish (US)
Pages (from-to)497-501
Number of pages5
JournalNew Astronomy Reviews
Volume44
Issue number7-9
DOIs
StatePublished - Sep 2000

Fingerprint

galaxies
Seyfert galaxies
erg
x rays
quasars
discrimination
optical spectrum
analysis

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Hasinger, G., Lehmann, I., Schmidt, M., Gunn, J. E., Schneider, D. P., Giacconi, R., ... Zamorani, G. (2000). The contribution of narrow-line Seyfert 1 galaxies to the soft X-ray background. New Astronomy Reviews, 44(7-9), 497-501. https://doi.org/10.1016/S1387-6473(00)00087-7
Hasinger, G. ; Lehmann, I. ; Schmidt, M. ; Gunn, J. E. ; Schneider, D. P. ; Giacconi, R. ; Trümper, J. ; Zamorani, G. / The contribution of narrow-line Seyfert 1 galaxies to the soft X-ray background. In: New Astronomy Reviews. 2000 ; Vol. 44, No. 7-9. pp. 497-501.
@article{ba325a0ec8044374a7d4d7adc4d83b0c,
title = "The contribution of narrow-line Seyfert 1 galaxies to the soft X-ray background",
abstract = "The ROSAT Ultradeep HRI survey in the Lockman Hole contains a complete sample of 91 X-ray sources with fluxes in the 0.5-2 keV band larger than 1.2×10-15 erg cm-2 s-1, where over 75{\%} of the sources are quasars or Seyfert galaxies. During the course of our optical identification work, we have obtained optical spectra of 67 narrow emission line galaxies (NELG), which are physically not associated with the X-ray sources. We have derived the equivalent width (EW) and the full width at half maximum (FWHM) for the most prominent emission lines of 41 quasars and Seyfert galaxies taken from the ROSAT Deep Survey (RDS), which has a flux limit of 5.5×10-15 erg cm-2 s-1 in the 0.5-2.0 keV band. Furthermore, we have obtained the EW and FWHM values of the field NELGs. Here, we present the spectroscopic discrimination between RDS Seyfert galaxies and field galaxies (NELG). The analysis of the emission lines has revealed that a single object out of 69 spectroscopically identified AGN fits the optical criteria of narrow-line Seyfert 1 galaxies (NLS1). This may indicate that NLS1 contribute only marginally to the soft X-ray background, but we can not exclude a possible larger contribution.",
author = "G. Hasinger and I. Lehmann and M. Schmidt and Gunn, {J. E.} and Schneider, {D. P.} and R. Giacconi and J. Tr{\"u}mper and G. Zamorani",
year = "2000",
month = "9",
doi = "10.1016/S1387-6473(00)00087-7",
language = "English (US)",
volume = "44",
pages = "497--501",
journal = "New Astronomy Reviews",
issn = "1387-6473",
publisher = "Elsevier",
number = "7-9",

}

Hasinger, G, Lehmann, I, Schmidt, M, Gunn, JE, Schneider, DP, Giacconi, R, Trümper, J & Zamorani, G 2000, 'The contribution of narrow-line Seyfert 1 galaxies to the soft X-ray background', New Astronomy Reviews, vol. 44, no. 7-9, pp. 497-501. https://doi.org/10.1016/S1387-6473(00)00087-7

The contribution of narrow-line Seyfert 1 galaxies to the soft X-ray background. / Hasinger, G.; Lehmann, I.; Schmidt, M.; Gunn, J. E.; Schneider, D. P.; Giacconi, R.; Trümper, J.; Zamorani, G.

In: New Astronomy Reviews, Vol. 44, No. 7-9, 09.2000, p. 497-501.

Research output: Contribution to journalReview article

TY - JOUR

T1 - The contribution of narrow-line Seyfert 1 galaxies to the soft X-ray background

AU - Hasinger, G.

AU - Lehmann, I.

AU - Schmidt, M.

AU - Gunn, J. E.

AU - Schneider, D. P.

AU - Giacconi, R.

AU - Trümper, J.

AU - Zamorani, G.

PY - 2000/9

Y1 - 2000/9

N2 - The ROSAT Ultradeep HRI survey in the Lockman Hole contains a complete sample of 91 X-ray sources with fluxes in the 0.5-2 keV band larger than 1.2×10-15 erg cm-2 s-1, where over 75% of the sources are quasars or Seyfert galaxies. During the course of our optical identification work, we have obtained optical spectra of 67 narrow emission line galaxies (NELG), which are physically not associated with the X-ray sources. We have derived the equivalent width (EW) and the full width at half maximum (FWHM) for the most prominent emission lines of 41 quasars and Seyfert galaxies taken from the ROSAT Deep Survey (RDS), which has a flux limit of 5.5×10-15 erg cm-2 s-1 in the 0.5-2.0 keV band. Furthermore, we have obtained the EW and FWHM values of the field NELGs. Here, we present the spectroscopic discrimination between RDS Seyfert galaxies and field galaxies (NELG). The analysis of the emission lines has revealed that a single object out of 69 spectroscopically identified AGN fits the optical criteria of narrow-line Seyfert 1 galaxies (NLS1). This may indicate that NLS1 contribute only marginally to the soft X-ray background, but we can not exclude a possible larger contribution.

AB - The ROSAT Ultradeep HRI survey in the Lockman Hole contains a complete sample of 91 X-ray sources with fluxes in the 0.5-2 keV band larger than 1.2×10-15 erg cm-2 s-1, where over 75% of the sources are quasars or Seyfert galaxies. During the course of our optical identification work, we have obtained optical spectra of 67 narrow emission line galaxies (NELG), which are physically not associated with the X-ray sources. We have derived the equivalent width (EW) and the full width at half maximum (FWHM) for the most prominent emission lines of 41 quasars and Seyfert galaxies taken from the ROSAT Deep Survey (RDS), which has a flux limit of 5.5×10-15 erg cm-2 s-1 in the 0.5-2.0 keV band. Furthermore, we have obtained the EW and FWHM values of the field NELGs. Here, we present the spectroscopic discrimination between RDS Seyfert galaxies and field galaxies (NELG). The analysis of the emission lines has revealed that a single object out of 69 spectroscopically identified AGN fits the optical criteria of narrow-line Seyfert 1 galaxies (NLS1). This may indicate that NLS1 contribute only marginally to the soft X-ray background, but we can not exclude a possible larger contribution.

UR - http://www.scopus.com/inward/record.url?scp=0007111615&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0007111615&partnerID=8YFLogxK

U2 - 10.1016/S1387-6473(00)00087-7

DO - 10.1016/S1387-6473(00)00087-7

M3 - Review article

AN - SCOPUS:0007111615

VL - 44

SP - 497

EP - 501

JO - New Astronomy Reviews

JF - New Astronomy Reviews

SN - 1387-6473

IS - 7-9

ER -