LOCATION: Sport & Kurhotel at Bad Moos - Via Val Fiscalina 27, 39030, Sexten
The Universe is populated with bright “Cosmic Beacons”, such as supernovae (SNe), quasars (accreting super-massive black holes at the center of galaxies) and long gamma-ray bursts (GRBs; catastrophic death of massive and rapidly rotating stars). These objects span a large range of distances and energetic processes, enabling the study of cosmological expansion, large-scale structure, feedback mechanisms and distant galaxies, both their dark and baryonic components. This workshop aims at bringing together expert from different areas to highlight the broad consensus and open questions on:
(a) different probes of concordance cosmology, and possible departures from flat-LCDM;
(b) tracing large scale-structures using the brightest sources in the Universe, both in emission and absorption;
(c) the co-evolution of quasars and their hosts;
(d) probing galaxies using QSOs, SNe and GRB afterglows.
Strongly lensed time-variable sources, like quasars and supernovae, give one-step measurements of cosmological parameters and hence the expansion history of the Universe. Besides cosmography, lensed quasars and supernovae give a super-resolved view of their distant host galaxies at z~2, and a direct measurement of dark matter halos masses in galaxies at z~0.4-1.
The brightest sources along cosmic times can be used to trace the large-scale structures. First, new sensitive instruments are now able to unveil extended Lyman-Alpha emission on hundreds of kpc scales at high redshift (z>2) mainly powered by the strong ionising radiation originating in “Cosmic Beacons” (e.g., quasars). Second, the use of the information enclosed in the Lyman-Alpha absorption signatures in bright background sight-lines has led to the development of tomographic reconstructions of the intergalactic medium. These two techniques are complementary and are opening the path to a better understanding of the physical conditions on such large scales.
Quasar host galaxies appear more massive and more star-forming than the typical galaxy at their cosmic time, and reside in some of the most massive halos. Having a tremendous luminosity, a quasar is in principle able to expel or/and highly ionize the gaseous reservoir within the host and its surrounding (up to intergalactic scales), thus regulating its own growth. In turn, a complex interplay of accretion, star formation, winds and outflows is thus expected to affect galaxy formation on this massive regime.
Using the bright light of QSOs and GRBs, it is possible to study, in absorption, the chemistry of the gas and dust, the physical conditions, and the kinematics of the interstellar (ISM) and circumgalactic medium (CGM) of distant galaxies. Superluminous Supernovae (SLSNe) are a rare and new class of distant SNe that are magnitudes brighter than classical SNe, including cosmological SN Type Ia, and might be standardizable candles. Thus, QSOs, GRBs, and SLSNe can reveal detailed and important information on the distant ISM and CGM that are complementary to classical, flux-limited observations of high-z galaxies.
We are entering a breathtaking epoch for astronomy with the advent of unique and extraordinary facilities, on the ground and in space. ALMA has opened the path to high resolution astronomy in the submillimeter regime with unrivaled sensitivity. Wide-field, integral-field spectrographs with unprecedented capabilities are now available: the Multi-Unit Spectroscopic Explorer (MUSE) at the ESO/VLT and Cosmic Web Imager at KECK (KCWI). The E-ELT and TMT will push our sensitivity, spatial and spectral resolution to an unimaginable level. In space, the JWST will open a new window in the study of primordial epochs, complementing the UV-restframe capabilities of HST. For example, JWST is expected to be able to observe SLSNe all the way to z~20. In addition, the upcoming SVOM and the proposed THESEUS will dramatically increase the number of high-z GRBs. This workshop on `Cosmic Beacons’ thus aims at connecting young experts and tackle together the open questions and future opportunities.
Adriano Agnello (ESO-Garching & Dark-KU)
Fabrizio Arrigoni Battaia (ESO-Garching & MPA-Garching)
Annalisa De Cia (ESO-Garching)