We present direct evidence for anomalous microwave emission in the Perseus molecular cloud, which shows a clear rising spectrum from 11 to 17 GHz in the data from the COSMOSOMAS experiment. By extending the frequency coverage using W ilkinson Microwave Anisotropy Probe maps convolved with the COSMOSOMAS scanning pattern, we reveal a peak flux density of 424 Jy at 22 GHz integrated over an extended area of 1°.65 x1°. 0 centered on R.A.= 55°.4+/-0°.1 and decl. =31°.8+/-0°.1 (J2000). The flux density that we measure at this frequency is nearly an order of magnitude higher than can be explained in terms of normal Galactic emission processes (synchrotron, free-free, and thermal dust). An extended IRAS dust feature, G159.6-18.5, is found near this position, and no bright unresolved source that could be an ultracompact H ii region or gigahertz-peaked source could be found. An adequate fit for the spectral density distribution can be achieved from 10 to 50 GHz by including a very significant contribution from electric dipole emission from small spinning dust grains.
Detection of anomalous microwave emission in the Perseus molecular cloud with the COSMOSOMAS experiment / WATSON R., A; Rebolo, R; RUBINO MARTIN J., A; Hildebrandt, S; GUTIERREZ C., M; FERNANDEZ CEREZO, S; HOYLAND R., J; Battistelli, Elia Stefano. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - 624:(2005), pp. 89-92. [10.1086/430519]
Detection of anomalous microwave emission in the Perseus molecular cloud with the COSMOSOMAS experiment
BATTISTELLI, Elia Stefano
2005
Abstract
We present direct evidence for anomalous microwave emission in the Perseus molecular cloud, which shows a clear rising spectrum from 11 to 17 GHz in the data from the COSMOSOMAS experiment. By extending the frequency coverage using W ilkinson Microwave Anisotropy Probe maps convolved with the COSMOSOMAS scanning pattern, we reveal a peak flux density of 424 Jy at 22 GHz integrated over an extended area of 1°.65 x1°. 0 centered on R.A.= 55°.4+/-0°.1 and decl. =31°.8+/-0°.1 (J2000). The flux density that we measure at this frequency is nearly an order of magnitude higher than can be explained in terms of normal Galactic emission processes (synchrotron, free-free, and thermal dust). An extended IRAS dust feature, G159.6-18.5, is found near this position, and no bright unresolved source that could be an ultracompact H ii region or gigahertz-peaked source could be found. An adequate fit for the spectral density distribution can be achieved from 10 to 50 GHz by including a very significant contribution from electric dipole emission from small spinning dust grains.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
