Found 7 talks width keyword gravitational lensing

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.

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.

The Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes reported the discovery of the most distant gamma-ray source ever observed at very high energies, thanks to the “replay” of an enormous flare by a galactic gravitational lens as foreseen by Einstein’s General Relativity. QSO B0218+357 is a gravitationally lensed blazar located at a redshift of 0.944. The gravitational lensing splits the emitted radiation into two components separated by a 10–12 day delay. In July 2014, QSO B0218+357 experienced a violent flare observed by the Fermi-LAT and followed by the MAGIC telescopes. The spectral energy distribution of QSO B0218+357 can give information on the energetics of z ~ 1 very high energy gamma-ray sources. Moreover the gamma-ray emission can also be used as a probe of the extragalactic background light at z ~ 1. MAGIC performed observations of QSO B0218+357 during the expected arrival time of the delayed component of the emission. The MAGIC and Fermi-LAT observations were accompanied by quasi-simultaneous optical data from the KVA telescope and X-ray observations by Swift-XRT. We construct a multiwavelength spectral energy distribution of QSO B0218+357 and use it to model the source. The GeV and sub-TeV data obtained by Fermi-LAT and MAGIC are used to set constraints on the extragalactic background light. Very high energy gamma-ray emission was detected from the direction of QSO B0218+357 by the MAGIC telescopes during the expected time of arrival of the trailing component of the flare, making it the farthest very high energy gamma-ray source detected to date. The combined MAGIC and Fermi-LAT spectral energy distribution of QSO B0218+357 is consistent with current extragalactic background light models. The broadband emission can be modeled in the framework of a two-zone external Compton scenario, where the GeV emission comes from an emission region in the jet, located outside the broad line region.

Work published in A&A 595, A98 (2016) ( http://www.aanda.org/articles/aa/abs/2016/11/aa29461-16/aa29461-16.html)

https://magic.mpp.mpg.de/outsiders/results/magic-highlights-5/

http://www.iac.es/divulgacion.php?op1=16&id=1133

Galaxy groups have an important role in the hierarchical assembly of structures in the Universe. Since galaxy groups are much more massive than galaxy-scale halos and are concentrated enough, they can act as lenses. The study of dark matter profiles can be very successfully using group-scale lenses, being that galaxy groups are quite abundant compared to galaxy clusters, and are easy to model. However, these have the disadvantage of the lack of constraints. In this talk, I will show how is possible to constrain the scale radius of the NFW profile using the velocity dispersion of the galaxy group. In particular I will present the results obtained with SL2SJ 02140-0535, a group which belongs to the Strong Lensing Legacy Survey - ARCS (SARCS) sample compiled from the final T0006 data release of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS).

In the Λ-CDM galaxy formation paradigm, the star formation history of a galaxy is coupled to the total mass of its dark matter halo through processes like galaxy-galaxy merging, satellite accretion, and gas retention. Globular cluster formation is known to coincide with strong star formation events in the early Universe. To develop an accurate model of galaxy formation, the relationship between such systems and their hosting dark matter halos must be understood. Employing weak gravitational lensing galaxy mass analysis, we have discovered that the number of globular clusters in a given galaxy is directly proportional to its total dark matter halo mass. This result holds in both dwarf and giant ellipticals, spirals and in all types of galaxy environments. I will present these observations and initiate a discussion on the implications for scenarios of globular cluster system formation and evolution.