R. J. Hoyland

Detection of Anomalous Microwave Emission in the Perseus Molecular Cloud with the COSMOSOMAS Experiment

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 42 ± 4 Jy at 22 GHz integrated over an extended area of 165 × 10 centered on R.A. = 554 ± 01 and decl. = +318 ± 01 (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.

Polarization observations of the anomalous microwave emission in the Perseus molecular complex with the cosmosomas experiment

The anomalous microwave emission detected in the Perseus molecular complex by Watson et al. has been observed at 11 GHz through dual orthogonal polarizations with the COSMOSOMAS experiment. Stokes U and Q maps were obtained at a resolution of � 0 ◦ .9 for a 30 ◦ ×30 ◦ region including the Perseus molecular complex. A faint polarized emission has been measured; we find Q = 0.2% ± 1.0%, while U = 3.4 +1.8 −1.4 % both at the 95% confidence level with a systematic uncertainty estimated to be lower than 1% determined from tests of the instrumental performance using unpolarized sources in our map as null hypothesis. The resulting total polarization level is � = 3.4 +1.5 −1.9 %. These are the first constraints on the polarization properties of an anomalous microwave emission source. The low level of polarization seems to indicate that the particles responsible for this emission in the Perseus molecular complex are not significantly aligned in a common direction over the whole region, as a consequence of either a high structural symmetry in the emitting particle or a low-intensity magnetic field. Our weak detection is fully consistent with predictions from electric dipole emission and resonance relaxation at this frequency.

COSMOSOMAS observations of the cosmic microwave background and Galactic foregrounds at 11 GHz: evidence for anomalous microwave emission at high Galactic latitude

We present observations with the new 11-GHz radiometer of the COSMOSOMAS experiment at the Teide Observatory (Tenerife). The sky region between 0°≤ RA ≤ 360° and 26°≤ Dec. ≤ 49° (ca. 6500 deg2) was observed with an angular resolution of . Two orthogonal independent channels in the receiving system measured total power signals from linear polarizations with a 2-GHz bandwidth. Maps with an average sensitivity of 50 μK per beam have been obtained for each channel. At high Galactic latitude (|b| > 30°) the 11-GHz data are found to contain the expected cosmic microwave background (CMB) as well as extragalactic radiosources, galactic synchrotron and free–free emission, and a dust-correlated component which is likely of Galactic origin. At the angular scales allowed by the window function of the experiment, the 100–240 μm dust-correlated component presents an amplitude ΔT∼ 9–13 μK while the CMB signal is of the order of 27 μK. The spectral behaviour of the dust-correlated signal is examined in the light of previous COSMOSOMAS data at 13–17 GHz and Wilkinson Microwave Anisotropy Probe data at 22–94 GHz in the same sky region. We detect a flattening in the spectral index of this signal below 20 GHz which rules out synchrotron radiation as being responsible for the emission. This anomalous dust emission can be described by a combination of free–free emission and spinning dust models with a flux density peaking around 20 GHz.

The Quijote CMB Experiment

We present the current status of the QUIJOTE (Q-U-I JOint TEnerife) CMB Experiment, a new instrument which will start operations early in 2009 at Teide Observatory with the aim of characterizing the polarization of the CMB and other processes of galactic and extragalactic emission in the frequency range 10–30GHz and at large angular scales. QUIJOTE will be a valuable complement at low frequencies for the PLANCK mission, and will have the required sensitivity to detect a primordial gravitational-wave component if the tensor-to-scalar ratio is larger than r = 0.05.

Planck pre-launch status: Low Frequency Instrument calibration and expected scientific performance

We present the calibration and scientific performance parameters of the Planck Low Frequency Instrument (LFI) measured during the ground cryogenic test campaign. These parameters characterise the instrument response and constitute our optimal pre-launch knowledge of the LFI scientific performance. The LFI shows excellent 1/f stability and rejection of instrumental systematic effects; its measured noise performance shows that LFI is the most sensitive instrument of its kind. The calibration parameters will be updated during flight operations until the end of the mission.

QUIJOTE scientific results – I. Measurements of the intensity and polarisation of the anomalous microwave emission in the Perseus molecular complex

In this paper, we present Q-U-I JOint Tenerife Experiment (QUIJOTE) 10-20 GHz observations (194 h in total over ???250 deg2) inintensity and polarisation of G159.6-18.5, one of the most widelystudied regions harbouring anomalous microwave emission (AME). Bycombining with other publicly available intensity data, we achieve themost precise spectrum of the AME measured to date in an individualregion, with 13 independent data points between 10 and 50 GHz beingdominated by this emission. The four QUIJOTE data points provide thefirst independent confirmation of the downturn of the AME spectrum atlow frequencies, initially unveiled by the COSMOlogical Structures OnMedium Angular Scales experiment in this region. Our polarisation maps,which have an angular resolution of ???1?? and a sensitivity of ???25 ??K beam-1, are consistent with zero polarisation. Weobtain upper limits on the polarisation fraction of ?? {\textless} 6.3 and{\textless}2.8 per cent (95 per cent C.L.), respectively, at 12 and 18 GHz(??AME {\textless} 10.1 and {\textless}3.4 per cent with respect to theresidual AME intensity), a frequency range where no AME polarisationobservations have been reported to date. The combination of theseconstraints with those from other experiments confirm that all themagnetic dust models based on single-domain grains, and most of thoseconsidering randomly oriented magnetic inclusions, predict higherpolarisation levels than is observed towards regions with AME. Also,neither of the two considered models of electric dipole emission seemsto be compatible with all the observations together. More stringentconstraints of the AME polarisation at 10-40 GHz are necessary todisentangle between different models, to which future QUIJOTE data willcontribute.

Observations of the cosmic microwave background and galactic foregrounds at 12–17 GHz with the COSMOSOMAS experiment

We present the analysis of the first 18 months of data obtained with the COSMOSOMAS (COSMOlogical Structures On Medium Angular Scales) experiment at the Teide Observatory (Tenerife). Three maps have been obtained at 12.7, 14.7 and 16.3 GHz covering 9000 deg 2 each with a resolution of ∼ 1 ° and with sensitivities 49, 59 and 115 μK beam -1 , respectively. These data in conjunction with the Wilkinson Microwave Anisotropy Probe (WMAP) first year maps have revealed that the cosmic microwave background (CMB) is the dominant astronomical signal at high galactic latitude (|b| > 40°) in the three COSMOSOMAS channels with an average amplitude of 29.7 ± 1.0 μK (68 per cent c.1. not including calibration errors). This value is in agreement with the predicted CMB signal in the COSMOSOMAS maps using the best-fitting A-CDM model to the WMAP power spectrum. Cross-correlation analysis of the 408-MHz map and the COSMOSOMAS data at high galactic latitudes give values in the range 17.0-14.4 μK from 12.7 to 16.3 GHz. Removing detected point sources in this template, reduces the amplitude of the correlated signal to 8-9 μK. The mean spectral index of the correlated signal between the 408 MHz desourced and the COSMOSOMAS maps is between -3.20 and -2.94 at |b| > 40° which indicates that this signal is due to synchrotron emission. Cross-correlation of COSMOSOMAS data with the Diffuse Infrared Background Experiment (DIRBE) map at 100 μm shows the existence of a common signal with amplitude 7.4 ± 1.1, 7.5 ± 1.1 and 6.5 ± 2.3 μK in the 12.7, 14.7 and 16.3 GHz COSMOSOMAS maps at |b| > 30°. Using the WMAP data, we find this DIRBE correlated signal rises from high to low frequencies flattening below ∼20 GHz. At higher galactic latitudes the average amplitude of the correlated signal with the DIRBE maps decreases slightly. The frequency behaviour of the COSMOSOMAS/WMAP correlated signal with DIRBE is not compatible with the expected tendency for thermal dust. A study of the Ha emission maps do not support free-free as a major contributor to that signal. Our results provide new evidence of a Galactic foreground with properties compatible with predictions by spinning dust models.

The QUIJOTE-CMB experiment: studying the polarisation of the galactic and cosmological microwave emissions

The QUIJOTE (Q-U-I JOint Tenerife) CMB Experiment will operate at the Teide Observatory with the aim of characterizing the polarisation of the CMB and other processes of Galactic and extragalactic emission in the frequency range of 10-40GHz and at large and medium angular scales. The first of the two QUIJOTE telescopes and the first multi-frequency (10-30GHz) instrument are already built and have been tested in the laboratory. QUIJOTE-CMB will be a valuable complement at low frequencies for the Planck mission, and will have the required sensitivity to detect a primordial gravitational-wave component if the tensor-to-scalar ratio is larger than r = 0.05.

The thirty gigahertz instrument receiver for the Q-U-I Joint Tenerife experiment: concept and experimental results

This paper presents the analysis, design, and characterization of the thirty gigahertz instrument receiver developed for the Q-U-I Joint Tenerife experiment. The receiver is aimed to obtain polarization data of the cosmic microwave background radiation from the sky, obtaining the Q, U, and I Stokes parameters of the incoming signal simultaneously. A comprehensive analysis of the theory behind the proposed receiver is presented for a linearly polarized input signal, and the functionality tests have demonstrated adequate results in terms of Stokes parameters, which validate the concept of the receiver based on electronic phase switching.

QUIJOTE Scientific Results. II. Polarisation Measurements of the Microwave Emission in the Galactic molecular complexes W43 and W47 and supernova remnant W44

This work has been partially funded by the Spanish Ministry of Economy and Competitiveness (MINECO) under the projects AYA2007-68058-C03-01, AYA2010-21766- C03-02, AYA2012-39475-C02-01, the Consolider-Ingenio project CSD2010-00064 (EPI: Exploring the Physics of Inflation) and also by the European Union’s Horizon 2020 research and innovation programme under grant agreement number 687312. FP thanks the European Commission under the Marie Sklodowska-Curie Actions within the H2020 program, Grant Agreement Number 658499-PolAME-H2020-MSCA-IF-2014.