Abstract
We study the source-subtracted near-infrared and X-ray background fluctuations of the COSMOS field using data from the Spitzer SPLASH program (∼1272 hr) and Chandra COSMOS Legacy Survey (4.6 Ms). The new auto-power spectra of the cosmic infrared and X-ray background fluctuations reach maximum angular scales of ∼3000″ and ∼5000″, respectively. We measure the cross-power spectra between each infrared and X-ray band and calculate the mean power above 20″. We find that the soft X-ray band is correlated with 3.6 and 4.5 μm at ∼4σ significance level. The significance between hard X-ray and the 3.6 μm (4.5 μm) band is ∼2.2σ (∼3.8σ). The combined infrared (3.6 + 4.5 μm) data are correlated with the X-ray data in soft ([0.5-2] keV), hard ([2-7] keV), and broad ([0.5-7] keV) bands at ∼5.6σ, ∼4.4σ, and ∼6.6σ levels, respectively. We compare the new measurements with existing models for the contributions from known populations at z < 7, which are not subtracted. The model predictions are consistent with the measurements, but we cannot rule out contributions from other components, such as Direct Collapse Black Holes (DCBH). However, the stacked cross-power spectra, combining other available data, show excess fluctuations about an order of magnitude on average at ∼4σ confidence at scales within ∼300″. By studying the X-ray SED of the cross-power signal, assuming no significant variation from the infrared, we find that its shape is consistent with DCBHs.
| Original language | English (US) |
|---|---|
| Article number | 141 |
| Journal | Astrophysical Journal |
| Volume | 864 |
| Issue number | 2 |
| DOIs | |
| State | Published - Sep 10 2018 |
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Keywords
- cosmology: observations
- infrared: diffuse background
- quasars: supermassive black holes
- X-rays: diffuse background
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
The SPLASH and Chandra COSMOS Legacy Survey : The Cross-power between Near-infrared and X-Ray Background Fluctuations. / Li, Yanxia; Cappelluti, Nico; Arendt, Richard G.; Hasinger, Günther; Kashlinsky, Alexander; Helgason, Kari.
In: Astrophysical Journal, Vol. 864, No. 2, 141, 10.09.2018.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The SPLASH and Chandra COSMOS Legacy Survey
T2 - The Cross-power between Near-infrared and X-Ray Background Fluctuations
AU - Li, Yanxia
AU - Cappelluti, Nico
AU - Arendt, Richard G.
AU - Hasinger, Günther
AU - Kashlinsky, Alexander
AU - Helgason, Kari
PY - 2018/9/10
Y1 - 2018/9/10
N2 - We study the source-subtracted near-infrared and X-ray background fluctuations of the COSMOS field using data from the Spitzer SPLASH program (∼1272 hr) and Chandra COSMOS Legacy Survey (4.6 Ms). The new auto-power spectra of the cosmic infrared and X-ray background fluctuations reach maximum angular scales of ∼3000″ and ∼5000″, respectively. We measure the cross-power spectra between each infrared and X-ray band and calculate the mean power above 20″. We find that the soft X-ray band is correlated with 3.6 and 4.5 μm at ∼4σ significance level. The significance between hard X-ray and the 3.6 μm (4.5 μm) band is ∼2.2σ (∼3.8σ). The combined infrared (3.6 + 4.5 μm) data are correlated with the X-ray data in soft ([0.5-2] keV), hard ([2-7] keV), and broad ([0.5-7] keV) bands at ∼5.6σ, ∼4.4σ, and ∼6.6σ levels, respectively. We compare the new measurements with existing models for the contributions from known populations at z < 7, which are not subtracted. The model predictions are consistent with the measurements, but we cannot rule out contributions from other components, such as Direct Collapse Black Holes (DCBH). However, the stacked cross-power spectra, combining other available data, show excess fluctuations about an order of magnitude on average at ∼4σ confidence at scales within ∼300″. By studying the X-ray SED of the cross-power signal, assuming no significant variation from the infrared, we find that its shape is consistent with DCBHs.
AB - We study the source-subtracted near-infrared and X-ray background fluctuations of the COSMOS field using data from the Spitzer SPLASH program (∼1272 hr) and Chandra COSMOS Legacy Survey (4.6 Ms). The new auto-power spectra of the cosmic infrared and X-ray background fluctuations reach maximum angular scales of ∼3000″ and ∼5000″, respectively. We measure the cross-power spectra between each infrared and X-ray band and calculate the mean power above 20″. We find that the soft X-ray band is correlated with 3.6 and 4.5 μm at ∼4σ significance level. The significance between hard X-ray and the 3.6 μm (4.5 μm) band is ∼2.2σ (∼3.8σ). The combined infrared (3.6 + 4.5 μm) data are correlated with the X-ray data in soft ([0.5-2] keV), hard ([2-7] keV), and broad ([0.5-7] keV) bands at ∼5.6σ, ∼4.4σ, and ∼6.6σ levels, respectively. We compare the new measurements with existing models for the contributions from known populations at z < 7, which are not subtracted. The model predictions are consistent with the measurements, but we cannot rule out contributions from other components, such as Direct Collapse Black Holes (DCBH). However, the stacked cross-power spectra, combining other available data, show excess fluctuations about an order of magnitude on average at ∼4σ confidence at scales within ∼300″. By studying the X-ray SED of the cross-power signal, assuming no significant variation from the infrared, we find that its shape is consistent with DCBHs.
KW - cosmology: observations
KW - infrared: diffuse background
KW - quasars: supermassive black holes
KW - X-rays: diffuse background
UR - http://www.scopus.com/inward/record.url?scp=85053418052&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85053418052&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/aad55a
DO - 10.3847/1538-4357/aad55a
M3 - Article
AN - SCOPUS:85053418052
VL - 864
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 141
ER -