Hostname: page-component-8448b6f56d-42gr6 Total loading time: 0 Render date: 2024-04-18T04:20:09.220Z Has data issue: false hasContentIssue false

Environmental Effects on Properties of Type 2 QSOs

Published online by Cambridge University Press:  03 June 2010

Lin-wen Chen
Affiliation:
Department of Earth Sciences, National Taiwan Normal University, Taipei, Taiwan
Li-Ting Hsu
Affiliation:
Department of Earth Sciences, National Taiwan Normal University, Taipei, Taiwan
Rights & Permissions [Opens in a new window]

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Type 2 QSOs (QSO2s) are intrinsically luminous QSOs embedded in dusty environments. In this work, we study the radio, optical, and soft X-ray properties of 887 optically selected [O III]-based QSO2s (Reyes et al. 2008) at z<0.83 to investigate the connection between QSO2s and their environments. We use SDSS data to measure the luminosity-limited galaxy counts in a volume centered on each QSO2 and defined by Δ z<0.1 (based on photometric redshifts) and within a projected distance of 1.5 Mpc of the QSO2 (δ1.5Mpc). We used ROSAT All Sky Survey (RASS) data to estimate the X-ray excess. Hsu & Chen (2010), after correcting for Galactic absorption, obtain a lower limit for the intrinsic neutral hydrogen column density (NH) toward each of the QSO2s. About 50% of these sources have NH > 1022 cm−2. We take this value as a threshold to subdivide QSO2s into high- and low-NH groups, and compare their environments. The distributions δ1.5Mpc of the two populations show that, in regions of higher galaxy density, QSO2s are dominated by the high-NH population (Figure 1), suggesting a closer connection between more obscured QSO2s and surrounding galaxies.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2010

References

Hsu, L. T. & Chen, L-w. 2010, in preparationGoogle Scholar
Reyes, R., Zakamska, N. L., Strauss, M. A., Green, J., Krolik, J. H., Shen, Y., Richards, G. T., Anderson, S. F., & Schneider, D. P. 2008, AJ, 136, 2373CrossRefGoogle Scholar