Found 8 talks width keyword Microwave emission
Simons Observatory (SO) is a new Cosmic Microwave Background telescope currently under construction in the Atacama Desert, close to ALMA and other recent CMB telescopes. It will have six small aperture (42cm) telescopes (SATs), and one large aperture (6m) telescope (LAT), observing at 30-280GHz (1-10mm) using transition edge sensors (TES) and kinetic inductance detectors (KIDs). As well as observing the polarisation of the CMB to unprecedented sensitivity, the LAT will perform a constant survey at higher angular resolution, enabling the systematic detection of transient sources in the submm, with large overlap of optical surveys such as LSST, DESI and DES. As well as giving an overview of SO, I summarise the types of transient sources that are expected to be seen by SO, including flaring stars, quasars, asteroids, and man-made satellites.
I will review the status of the QUIJOTE (Q-U-I JOint TEnerife) experiment, a project led from the IAC with the aim of characterising the polarisation of the Cosmic Microwave Background (CMB) and other galactic or extragalactic physical processes that emit in microwaves in the frequency range 10-42GHz, and at large angular scales (1 degree resolution). QUIJOTE consists of two telescopes and three instruments operating from the Teide Observatory, and started operations about 10 years ago, in November 2012.
I will discuss the status of the project, and I will present the latest scientific results associated with the wide survey carried out with the first QUIJOTE instrument (MFI) at 11, 13, 17 and 19GHz, covering approximately 29000 deg$^2$ with polarisation sensitivities in the range of 35-40 $\mu$K/deg. These MFI maps provide the most accurate description we have of the polarization of the emission of the Milky Way in the microwave range, in a frequency domain previously unexplored by other experiments. These maps provide a unique view of the Galactic
magnetic field as traced by the synchrotron emission. These results have been presented in an initial series of 6 scientific articles published on January 12th, 2023.
Finally, I will describe the prospects for future CMB observations from the Teide Observatory.
The search for the primordial B-modes polarization in the cosmic microwave background (CMB) radiation,
carrying the signature of the primordial gravitational waves from the inflation epoch, motivated a significant
technological progress enabling the next generation of CMB instruments (e.g. CMB-S4, LiteBIRD)
to reach an unprecedented sensitivity. However, such a challenging detection demands a very high control
of the instrumental systematics and CMB foreground emissions.
Among those, the galactic dust polarized emission spectral dependence, not yet fully
characterized, could leave a high level of uncertainty in the cosmological polarization data
producing an ambiguous detection of the CMB B-modes.
Characterizing the dust spectral energy distribution (SED) spatial variations became one of
the most critical issues in the quest for primordial B-modes.
In the work that I will present we have used the release of the Planck satellite HFI data
obtained with the software Sroll2 (Delouis+2019, A&A 629, A38), in order to characterize
and compare the SEDs for polarization and total intensity.
The mean SEDs for dust polarization and total intensity from 353 to 100 GHz are confirmed
to be remarkably close. However, the data show evidence for spatial variations of the
polarization SED. These variations are correlated with variations of dust temperature
measured on total intensity data but the correlation is tight only in the Galactic plane.
At higher latitudes, by considering 90% of useful sky fraction and less, the amplitude of the dust
emission residuals in polarization suggests that an additional contribution, coming from
variations of the polarization angle, becomes dominant. Current models, which extrapolate
the SED spatial variations from total intensity to polarization, would be therefore grossly
simplifying and underestimating the foreground signal to CMB polarization.
In this talk, we shall review the impact of the neutrino properties on the different cosmological observables. We shall also present the latest cosmological constraints on the neutrino masses and on the effective number of relativistic species. Special attention would be devoted to the role of neutrinos in solving the present cosmological tensions.
Durante este seminario se hará un recorrido sobre la instrumentación dentro del proyecto QUIJOTE, desde de los instrumentos ya existentes y su problemática hasta el estado actual de los instrumentos de nueva generación y los posibles desarrollos a futuro.
Dr Roger Hoyland has been working at the IAC for the last 21 years on the Cosmic Microwave Background Experiments. He started out as a research assistant at Jodrell Bank, University of Manchester, near his home town. His expertise lies in sensitive microwave radiometer design. He has worked on various projects such as the Tenerife Experiments, The Planck Surveyor Mission and The QUIJOTE project.
This talk is for the general public (even if mostly scientific) and aims to explain some of the misunderstandings and myths about microwave devices that we use in our everyday life. There are many YouTube videos about the effects of microwaves but which do you believe? Does your mobile phone really cause interference in an airplane? Can you really destroy your credit card by carrying it next to your mobile? Does the EMP bomb really exist? All this and more…………….
With the help of several live experiments and some audience participation (be prepared!) you will find out the science behind the myths around mobiles, microwave ovens and other microwave devices.
PS: Please bring along your mobile phone if you have one.
The European Space Agency's Planck satellite was launched on 14 May 2009, and has been surveying the sky stably and continuously since 13 August 2009. Its performance is well in line with expectations, and it will continue to gather scientific data until the end of its cryogenic lifetime. I will present the first scientific results of the mission, which appeared as a series of 26 papers at the beginning of this year 2011, covering a variety of astrophysical topics. In particular, I will focus on the results on galactic diffuse emissions, as well as the first results on galaxy clusters detected by means of the Sunyaev-Zeldovich effect.
The anomalous microwave emission (AME) is an additional diffuse foreground component, originated by an emission mechanism in the ISM different from the well-known synchrotron, free-free and thermal dust emissions. It was first discovered at the end of the nineties as a correlated signal between microwave CMB maps and infrared maps tracing the dust emission. Ever since several detections have been found in individual clouds in our Galaxy. This emission is an important contaminant for current and future CMB experiments, and therefore its characterization (both in temperature and in polarization) and understanding is mandatory. So far different theoretical models have been proposed to explain the physical mechanism that give rise to this emission. In this talk we will review these models and will present the current observational status of the AME, with particular emphasis on some recent studies that have been performed by our group in the IAC in the Perseus molecular complex and in the Pleiades reflection nebula.
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