Abstract
We present the first results of the measurements of angular auto-correlation functions (ACFs) of X-ray point sources detected in the XMM-Newton observations of the ∼2 deg 2 COSMOS field (COSMOS XMM-Newton). Significant positive signals have been detected in the 0.5-2 (SFT) band, in the angle range of 0.5′-24′, while the positive signals were at the ∼2 and ∼3 σ levels in the 2-4.5 (MED) and 4.5-10 (UHD) keV bands, respectively. Correctly taking integral constraints into account is a major limitation in interpreting our results. With power-law fits to the ACFs without the integral constraint term, we find correlation lengths of θ c = 1.9″ ± 0.3″ , 0.8″ -0.4″ +0.5″ and 6″ ± 2″ for the SFT, MED, and UHD bands, respectively, for γ = 1.8. The inferred comoving correlation lengths, also taking into account the bias by the source merging due to XMM-Newton PSF, are r c ≈ 9.8 ± 0.7, 5.8 -1.7 +1.4, and 12 ± 2 h -1 Mpc at the effective redshifts of z̄ eff ≈1.1, 0.9, and 0.6 for the SFT, MED, and UHD bands, respectively. If we include the integral constraint term in the fitting process, assuming that the power law extends to the scale length of the entire COSMOS XMM-Newton field, the correlation lengths become larger by ∼20%-90%. Comparing the inferred rms fluctuations of the spatial distribution of AGNs σ 8,AGN with those of the underlying mass, the bias parameters of the X-ray source clustering at these effective redshifts are in the range b AGN = 1.5-4.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 396-405 |
| Number of pages | 10 |
| Journal | Astrophysical Journal, Supplement Series |
| Volume | 172 |
| Issue number | 1 |
| DOIs | |
| State | Published - Oct 22 2007 |
| Externally published | Yes |
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Keywords
- Galaxies: active
- Quasars: general
- X-rays: galaxies
ASJC Scopus subject areas
- Space and Planetary Science
Cite this
The XMM-Newton wide-field survey in the COSMOS field. V angular clustering of the X-ray point sources. / Miyaji, Takamitsu; Zamorani, Giovanni; Cappelluti, Nico; Gilli, Roberto; Griffiths, Richard E.; Comastri, Andrea; Hasinger, Günther; Brusa, Marcella; Fiore, Fabrizio; Puccetti, Simonetta; Guzzo, Luigi; Finoguenov, Alexis.
In: Astrophysical Journal, Supplement Series, Vol. 172, No. 1, 22.10.2007, p. 396-405.Research output: Contribution to journal › Review article
}
TY - JOUR
T1 - The XMM-Newton wide-field survey in the COSMOS field. V angular clustering of the X-ray point sources
AU - Miyaji, Takamitsu
AU - Zamorani, Giovanni
AU - Cappelluti, Nico
AU - Gilli, Roberto
AU - Griffiths, Richard E.
AU - Comastri, Andrea
AU - Hasinger, Günther
AU - Brusa, Marcella
AU - Fiore, Fabrizio
AU - Puccetti, Simonetta
AU - Guzzo, Luigi
AU - Finoguenov, Alexis
PY - 2007/10/22
Y1 - 2007/10/22
N2 - We present the first results of the measurements of angular auto-correlation functions (ACFs) of X-ray point sources detected in the XMM-Newton observations of the ∼2 deg 2 COSMOS field (COSMOS XMM-Newton). Significant positive signals have been detected in the 0.5-2 (SFT) band, in the angle range of 0.5′-24′, while the positive signals were at the ∼2 and ∼3 σ levels in the 2-4.5 (MED) and 4.5-10 (UHD) keV bands, respectively. Correctly taking integral constraints into account is a major limitation in interpreting our results. With power-law fits to the ACFs without the integral constraint term, we find correlation lengths of θ c = 1.9″ ± 0.3″ , 0.8″ -0.4″ +0.5″ and 6″ ± 2″ for the SFT, MED, and UHD bands, respectively, for γ = 1.8. The inferred comoving correlation lengths, also taking into account the bias by the source merging due to XMM-Newton PSF, are r c ≈ 9.8 ± 0.7, 5.8 -1.7 +1.4, and 12 ± 2 h -1 Mpc at the effective redshifts of z̄ eff ≈1.1, 0.9, and 0.6 for the SFT, MED, and UHD bands, respectively. If we include the integral constraint term in the fitting process, assuming that the power law extends to the scale length of the entire COSMOS XMM-Newton field, the correlation lengths become larger by ∼20%-90%. Comparing the inferred rms fluctuations of the spatial distribution of AGNs σ 8,AGN with those of the underlying mass, the bias parameters of the X-ray source clustering at these effective redshifts are in the range b AGN = 1.5-4.
AB - We present the first results of the measurements of angular auto-correlation functions (ACFs) of X-ray point sources detected in the XMM-Newton observations of the ∼2 deg 2 COSMOS field (COSMOS XMM-Newton). Significant positive signals have been detected in the 0.5-2 (SFT) band, in the angle range of 0.5′-24′, while the positive signals were at the ∼2 and ∼3 σ levels in the 2-4.5 (MED) and 4.5-10 (UHD) keV bands, respectively. Correctly taking integral constraints into account is a major limitation in interpreting our results. With power-law fits to the ACFs without the integral constraint term, we find correlation lengths of θ c = 1.9″ ± 0.3″ , 0.8″ -0.4″ +0.5″ and 6″ ± 2″ for the SFT, MED, and UHD bands, respectively, for γ = 1.8. The inferred comoving correlation lengths, also taking into account the bias by the source merging due to XMM-Newton PSF, are r c ≈ 9.8 ± 0.7, 5.8 -1.7 +1.4, and 12 ± 2 h -1 Mpc at the effective redshifts of z̄ eff ≈1.1, 0.9, and 0.6 for the SFT, MED, and UHD bands, respectively. If we include the integral constraint term in the fitting process, assuming that the power law extends to the scale length of the entire COSMOS XMM-Newton field, the correlation lengths become larger by ∼20%-90%. Comparing the inferred rms fluctuations of the spatial distribution of AGNs σ 8,AGN with those of the underlying mass, the bias parameters of the X-ray source clustering at these effective redshifts are in the range b AGN = 1.5-4.
KW - Galaxies: active
KW - Quasars: general
KW - X-rays: galaxies
UR - http://www.scopus.com/inward/record.url?scp=35348893063&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=35348893063&partnerID=8YFLogxK
U2 - 10.1086/516579
DO - 10.1086/516579
M3 - Review article
AN - SCOPUS:35348893063
VL - 172
SP - 396
EP - 405
JO - Astrophysical Journal, Supplement Series
JF - Astrophysical Journal, Supplement Series
SN - 0067-0049
IS - 1
ER -