Infrared-correlated 31-GHz radio emission from Orion East IR-correlated radio emission from Orion East
Infrared-correlated 31-GHz radio emission from Orion East IR-correlated radio emission from Orion East
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Orion East 的红外相关 31 GHz 无线电发射 Orion East 的红外相关无线电发射
DOI：
10.1111/j.1365-2966.2010.17079.x
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发表时间：
2010
影响因子：
4.8
通讯作者：
Dickinson C
中科院分区：
文献类型：
--
作者：
Dickinson C
Lynds dark cloud LDN1622 represents one of the best examples of anomalous dust emission, possibly originating from small spinning dust grains. We present Cosmic Background Imager (CBI) 31-GHz data of LDN1621, a diffuse dark cloud to the north of LDN1622 in a region known as Orion East. A broken ring-like structure with diameter ≈20 arcmin of diffuse emission is detected at 31 GHz, at ≈20–30 mJy beam−1with an angular resolution of ≈5 arcmin. The ring-like structure is highly correlated with far-infrared (FIR) emission at 12–100 μm with correlation coefficients ofr≈ 0.7–0.8, significant at ∼10σ. The FIR-correlated emission at 31 GHz therefore appears to be mostly due to radiation associated with dust. Multifrequency data are used to place constraints on other components of emission that could be contributing to the 31-GHz flux. An analysis of the GB6 survey maps at 4.85 GHz yields a 3σ upper limit on free–free emission of 7.2 mJy beam−1(≲30 per cent of the observed flux) at the CBI resolution. The bulk of the 31-GHz flux therefore appears to be mostly due to dust radiation. Aperture photometry, at an angular resolution of 13 arcmin and with an aperture of diameter 30 arcmin, allowed the use ofIRASmaps and theWilkinson Microwave Anisotropy Probe5-yrW-band map at 93.5 GHz. A single modified blackbody model was fitted to the data to estimate the contribution from thermal dust, which amounts to ∼10 per cent at 31 GHz. In this model, an excess of 1.52 ± 0.66 Jy (2.3σ) is seen at 31 GHz. Correlations with theIRAS100 μm gave a coupling coefficient of 18.1 ± 4.4 μK (MJy sr−1)−1, consistent with the values found for LDN1622.
