The nature of X-ray selected extremely red objects

J. A. Stevens, M. J. Page, R. J. Ivison, Ian Small, I. Lehmann, G. Hasinger, G. Szokoly

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

We report on the X-ray, optical, near-infrared, submillimetre and radio properties of five extremely red objects (EROs) selected at X-ray wavelengths by XMM-Newton in the Lockman Hole field. They all have enough counts in the X-ray band to allow spectral fitting: four are most probably obscured, Compton-thin active galactic nuclei (AGNs) with redshift-dependent absorbing column densities of 1022-1024 cm-2, whilst the fifth is best fitted by a thermal spectrum and is likely to be a massive elliptical galaxy in a deep gravitational potential. Their optical/ near-infrared colours and sizes suggest that X-ray selected EROs comprise a mixture of dusty 'starburst' galaxies and non-dusty galaxies that are dominated by either starlight or light from an active nucleus. The colour diagnostics are supported by the submillimetre and radio data; the two AGNs with 'starburst' colours have submillimetre or radio flux densities that imply large star formation rates, whilst those with 'elliptical' colours do not. The one source detected in the submillimetre waveband has narrow emission lines at a redshift of 1.45. Although the bulk of its radio emission originates from processes other than star formation, it is most probably a radio-quiet ultraluminous infrared galaxy.

Original languageEnglish
Pages (from-to)249-258
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume342
Issue number1
DOIs
Publication statusPublished - Jun 11 2003

Fingerprint

radio
color
active galactic nuclei
x rays
galaxies
near infrared
starburst galaxies
elliptical galaxies
XMM-Newton telescope
radio emission
star formation rate
gravitational fields
newton
star formation
flux density
nuclei
wavelength
wavelengths

Keywords

  • Galaxies: Active
  • Infrared: Galaxies
  • Radio continuum: Galaxies
  • Submillimetre
  • X-rays: Galaxies

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Stevens, J. A., Page, M. J., Ivison, R. J., Small, I., Lehmann, I., Hasinger, G., & Szokoly, G. (2003). The nature of X-ray selected extremely red objects. Monthly Notices of the Royal Astronomical Society, 342(1), 249-258. https://doi.org/10.1046/j.1365-8711.2003.06534.x

The nature of X-ray selected extremely red objects. / Stevens, J. A.; Page, M. J.; Ivison, R. J.; Small, Ian; Lehmann, I.; Hasinger, G.; Szokoly, G.

In: Monthly Notices of the Royal Astronomical Society, Vol. 342, No. 1, 11.06.2003, p. 249-258.

Research output: Contribution to journalArticle

Stevens, JA, Page, MJ, Ivison, RJ, Small, I, Lehmann, I, Hasinger, G & Szokoly, G 2003, 'The nature of X-ray selected extremely red objects', Monthly Notices of the Royal Astronomical Society, vol. 342, no. 1, pp. 249-258. https://doi.org/10.1046/j.1365-8711.2003.06534.x
Stevens JA, Page MJ, Ivison RJ, Small I, Lehmann I, Hasinger G et al. The nature of X-ray selected extremely red objects. Monthly Notices of the Royal Astronomical Society. 2003 Jun 11;342(1):249-258. https://doi.org/10.1046/j.1365-8711.2003.06534.x
Stevens, J. A. ; Page, M. J. ; Ivison, R. J. ; Small, Ian ; Lehmann, I. ; Hasinger, G. ; Szokoly, G. / The nature of X-ray selected extremely red objects. In: Monthly Notices of the Royal Astronomical Society. 2003 ; Vol. 342, No. 1. pp. 249-258.
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