scholarly journals The THESEUS space mission: science goals, requirements and mission concept

2021 ◽  
Author(s):  
L. Amati ◽  
P.T. O’Brien ◽  
D. Götz ◽  
E. Bozzo ◽  
A. Santangelo ◽  
...  
Keyword(s):  
Time Domain ◽  
Gamma Ray ◽  
High Redshift ◽  
Space Mission ◽  
Neutrino Detectors ◽  
Transient Sources ◽  
Low Mass ◽  
The Universe ◽  
Shed Light ◽  
Open Issues

AbstractTHESEUS, one of the two space mission concepts being studied by ESA as candidates for next M5 mission within its Comsic Vision programme, aims at fully exploiting Gamma-Ray Bursts (GRB) to solve key questions about the early Universe, as well as becoming a cornerstone of multi-messenger and time-domain astrophysics. By investigating the first billion years of the Universe through high-redshift GRBs, THESEUS will shed light on the main open issues in modern cosmology, such as the population of primordial low mass and luminosity galaxies, sources and evolution of cosmic re-ionization, SFR and metallicity evolution up to the “cosmic dawn” and across Pop-III stars. At the same time, the mission will provide a substantial advancement of multi-messenger and time-domain astrophysics by enabling the identification, accurate localisation and study of electromagnetic counterparts to sources of gravitational waves and neutrinos, which will be routinely detected in the late ‘20s and early ‘30s by the second and third generation Gravitational Wave (GW) interferometers and future neutrino detectors, as well as of all kinds of GRBs and most classes of other X/gamma-ray transient sources. Under all these respects, THESEUS will provide great synergies with future large observing facilities in the multi-messenger domain. A Guest Observer programme, comprising Target of Opportunity (ToO) observations, will expand the science return of the mission, to include, e.g., solar system minor bodies, exoplanets, and AGN.

scholarly journals Gamma-ray bursts from stellar remnants: probing the Universe at high redshift

1998 ◽  
Vol 294 (1) ◽  
pp. L13-L17 ◽  
Author(s):  
R. A. M. J. Wijers ◽  
J. S. Bloom ◽  
J. S. Bagla ◽  
P. Natarajan
Keyword(s):  
Gamma Ray ◽  
High Redshift ◽  
Gamma Ray Bursts ◽  
The Universe

scholarly journals Soft gamma rays from low accreting supermassive black holes and connection to energetic neutrinos

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shigeo S. Kimura ◽  
Kohta Murase ◽  
Péter Mészáros
Keyword(s):  
Active Galactic Nuclei ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
High Energy ◽  
Hadronic Interactions ◽  
Neutrino Detectors ◽  
Accretion Flows ◽  
Diffuse Background ◽  
The Universe

AbstractThe Universe is filled with a diffuse background of MeV gamma-rays and PeV neutrinos, whose origins are unknown. Here, we propose a scenario that can account for both backgrounds simultaneously. Low-luminosity active galactic nuclei have hot accretion flows where thermal electrons naturally emit soft gamma rays via Comptonization of their synchrotron photons. Protons there can be accelerated via turbulence or reconnection, producing high-energy neutrinos via hadronic interactions. We demonstrate that our model can reproduce the gamma-ray and neutrino data. Combined with a contribution by hot coronae in luminous active galactic nuclei, these accretion flows can explain the keV – MeV photon and TeV – PeV neutrino backgrounds. This scenario can account for the MeV background without non-thermal electrons, suggesting a higher transition energy from the thermal to nonthermal Universe than expected. Our model is consistent with X-ray data of nearby objects, and testable by future MeV gamma-ray and high-energy neutrino detectors.

scholarly journals Simulating High-Redshift Disk Galaxies: Applications to Long Duration Gamma-Ray Burst Hosts

2008 ◽  
Vol 4 (S254) ◽  
pp. 35-40
Author(s):  
Brant E. Robertson
Keyword(s):  
Star Formation ◽  
Molecular Hydrogen ◽  
Gamma Ray ◽  
High Redshift ◽  
Disk Galaxies ◽  
Host Galaxies ◽  
Long Duration ◽  
Low Mass ◽  
Hydrodynamical Simulations ◽  
The Impact

AbstractThe efficiency of star formation governs many observable properties of the cosmological galaxy population, yet many current models of galaxy formation largely ignore the important physics of star formation and the interstellar medium (ISM). Using hydrodynamical simulations of disk galaxies that include a treatment of the molecular ISM and star formation in molecular clouds (Robertson & Kravtsov 2008), we study the influence of star formation efficiency and molecular hydrogen abundance on the properties of high-redshift galaxy populations. In this work, we focus on a model of low-mass, star forming galaxies at 1 ≲ z ≲ 2 that may host long duration gamma-ray bursts (GRBs). Observations of GRB hosts have revealed a population of faint systems with star formation properties that often differ from Lyman-break galaxies (LBGs) and more luminous high-redshift field galaxies. Observed GRB sightlines are deficient in molecular hydrogen, but it is unclear to what degree this deficiency owes to intrinsic properties of the galaxy or the impact the GRB has on its environment. We find that hydrodynamical simulations of low-stellar mass systems at high-redshifts can reproduce the observed star formation rates and efficiencies of GRB host galaxies at redshifts 1 ≲ z ≲ 2. We show that the compact structure of low-mass high-redshift GRB hosts may lead to a molecular ISM fraction of a few tenths, well above that observed in individual GRB sightlines. However, the star formation rates of observed GRB host galaxies imply molecular gas masses of 108 – 109M⊙ similar to those produced in the simulations, and may therefore imply fairly large average H2 fractions in their ISM.

COSMOLOGICAL SHOCK WAVES IN THE LARGE SCALE STRUCTURE OF THE UNIVERSE

2013 ◽  
Vol 23 ◽  
pp. 386-390
Author(s):  
RENYI MA ◽  
DONGSU RYU ◽  
HYESUNG KANG
Keyword(s):  
Shock Waves ◽  
Galaxy Clusters ◽  
Large Scale ◽  
Gamma Ray ◽  
High Redshift ◽  
Cosmic Ray ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Weak Shocks ◽  
The Universe

Based on the cosmological hydrodynamic simulation, we study the properties of shock waves formed during the formation of the large scale structure (LSS) of the universe, and investigate their contribution to the cosmic ray (CR) fraction in the intergalactic medium (IGM). It is found that while strong accretion shocks prevail at high redshift, weak internal shocks become dominant in the intracluster medium (ICM) as galaxy clusters form and virialize at low redshift, z < 1. The accumulated CR proton energy is likely to be less than 10 % of the thermal energy in the ICM, since weak shocks of M ≲ 3 are most abundant. This is consistent with the upper limit constrained by radio and gamma-ray observations of galaxy clusters. In the warm-hot medium (WHIM) inside filaments, CRs and gas could be almost in energy equipartition, since relatively stronger shocks of 5 ≲ M ≲ 10 are dominant there. We suggest that the non-thermal emissions from the CR electrons and protons accelerated by cosmological shock waves could provide a new way to detect the WHIM of the universe.

scholarly journals Updated f(T) gravity constraints from high-redshift cosmography

2015 ◽  
Vol 24 (14) ◽  
pp. 1550100 ◽  
Author(s):  
Ester Piedipalumbo ◽  
Enrica Della Moglie ◽  
Roberto Cianci
Keyword(s):  
Gamma Ray ◽  
Probability Distributions ◽  
High Redshift ◽  
Teleparallel Gravity ◽  
Gravity Theory ◽  
Gravity Models ◽  
Acoustic Oscillations ◽  
Dynamical Equations ◽  
Data Set ◽  
The Universe

In the last dozen years, a wide and variegated mass of observational data revealed that the universe is now expanding at an accelerated rate. In the absence of a well-based theory to interpret the observations, cosmography provides information about the evolution of the universe from measured distances, only assuming that the geometry can be described by the Friedmann–Lemaitre–Robertson–Walker metric. In this paper, we perform a high-redshift analysis which allows us to put constraints on the cosmographic parameters up to the fifth-order, thus inducing indirect constraints on any gravity theory. Here, we are interested in the so-called teleparallel gravity theory, [Formula: see text]. Actually, we use the analytical expressions of the present day values of [Formula: see text] and its derivatives as functions of the cosmographic parameters to map the cosmography region of confidences into confidence ranges for [Formula: see text] and its derivative. Moreover, we show how these can be used to test some teleparallel gravity models without solving the dynamical equations. Our analysis is based on the Union2 Type Ia supernovae (SNIa) data set, a set of 28 measurements of the Hubble parameter, the Hubble diagram constructed from some gamma ray bursts (GRB) luminosity distance indicators and Gaussian priors on the distance from the baryon acoustic oscillations (BAOs) and the Hubble constant [Formula: see text]. To perform our statistical analysis and to explore the probability distributions of the cosmographic parameters, we use the Markov chain Monte Carlo (MCMC) method.

Gamma-ray bursts spectral correlations and their cosmological use

2007 ◽  
Vol 365 (1854) ◽  
pp. 1385-1394 ◽  
Author(s):  
Giancarlo Ghirlanda
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Spectral Energy ◽  
Selection Effects ◽  
Emission Energy ◽  
X Ray ◽  
New Class ◽  
The Universe ◽  
Prompt Emission ◽  
Open Issues

The correlations involving the long-gamma-ray bursts (GRBs) prompt emission energy represent a new key to understand the GRB physics. These correlations have been proved to be the tool that makes long-GRBs a new class of standard candles. Gamma Ray Bursts, being very powerful cosmological sources detected in the hard X-ray band, represent a new tool to investigate the Universe in a redshift range, which is complementary to that covered by other cosmological probes (SNIa and CMB). A review of the , , and correlations is presented. Open issues related to these correlations (e.g. presence of outliers and selection effects) and to their use for cosmographic purposes (e.g. dependence on model assumptions) are discussed. Finally, the relevance of thermal components in GRB spectra is discussed in the light of some of the models recently proposed for the interpretation of the spectral-energy correlations.

THE INTERACTION BETWEEN GAMMA-RAY BURSTS AND THEIR ENVIRONMENT

2003 ◽  
Vol 18 (37) ◽  
pp. 2611-2625
Author(s):  
ROSALBA PERNA
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
Host Galaxies ◽  
High Energy Astrophysics ◽  
Wavelength Radiation ◽  
Nearby Galaxies ◽  
The Universe ◽  
Shed Light

Gamma-ray Bursts (GRBs) are the most energetic and most relativistic phenomenon in the Universe. Understanding the nature of their progenitors is among the primary efforts of current research in high energy astrophysics, and their unmatched luminosity and other properties makes them ideal cosmological probes. This review summarizes the observational effects resulting from the interaction between the longer-wavelength radiation accompanying GRBs and their close environment. In particular, it discusses signatures that, in addition to providing powerful clues on the GRB progenitors, can also shed light on the physical characteristics, such as metallicity and dust content, of the GRB host galaxies. The last part of the article reviews the long-term signatures imprinted in the medium after a GRB explosion, particularly focusing on how we can identify GRB remnants in our own and nearby galaxies, and what we can learn from their identification.

scholarly journals Flaring γ-ray emission from high redshift blazars

2016 ◽  
Author(s):  
Monica Orienti ◽  
Filippo D'Ammando ◽  
Marcello Giroletti ◽  
Justin Finke ◽  
Daniele Dallacasa
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
High Redshift ◽  
Significant Fraction ◽  
X Ray ◽  
Gamma Ray Emission ◽  
The Universe

High redshift blazars are among the most powerful objects in the Universe. Although they represent a significant fraction of the extragalactic hard X-ray sky, they are not commonly detected in gamma-rays. High redshift (z>2) objects represent

scholarly journals Observations of GRBs at high redshift

2007 ◽  
Vol 365 (1854) ◽  
pp. 1377-1384 ◽  
Author(s):  
Nial R Tanvir ◽  
Páll Jakobsson
Keyword(s):  
Gamma Ray ◽  
High Redshift ◽  
Cosmological Parameters ◽  
Gamma Ray Bursts ◽  
Star Formation History ◽  
Redshift Distribution ◽  
Formation History ◽  
History Of ◽  
The Universe

The extreme luminosity of gamma-ray bursts and their afterglows means they are detectable, in principle, to very high redshifts. Although the redshift distribution of gamma-ray bursts (GRBs) is difficult to determine, due to incompleteness of present samples, we argue that for Swift-detected bursts, the median redshift is between 2.5 and 3, with a few per cent probably at z >6. Thus, GRBs are potentially powerful probes of the era of reionization and the sources responsible for it. Moreover, it seems probable that they can provide constraints on the star-formation history of the Universe and may also help in the determination of the cosmological parameters.

scholarly journals The Fraction of Ionizing Photons Escaping from High-Redshift Galaxies

2010 ◽  
Vol 27 (1) ◽  
pp. 110-123 ◽  
Author(s):  
Jhan A. Srbinovsky ◽  
J. Stuart B. Wyithe
Keyword(s):  
Free Parameter ◽  
Critical Parameter ◽  
High Redshift ◽  
Host Galaxy ◽  
Minimum Mass ◽  
Ionize Hydrogen ◽  
High Redshift Galaxies ◽  
Low Mass ◽  
The Mean ◽  
The Universe

AbstractThe fraction (fesc) of ionizing photons that escape their host galaxy and so are able to ionize hydrogen in the intergalactic medium is a critical parameter in studies of the reionization era. In this paper we constrain fesc at high redshift by modelling the observed Lyα transmission. Using an N-body simulation of the cosmic web, we first model an ionizing background due to star-bursting galaxies. We then extract an ensemble of mock absorption spectra from the simulation and compute the mean transmission. We adjust the free parameter, fesc in our model of the ionizing background to reproduce the observed transmission. We find that fesc increases with the minimum galaxy mass considered to contribute to the ionizing background, and that at high redshift fesc must be greater than 5% irrespective of galaxy mass. Based on our numerical results we calibrate a semi-analytic model which shows that the ionizing background observed at z ∼ 5.5–6 implies a sufficient number of ionizing photons to have reionized the Universe by z ∼ 6. However, if the minimum mass for star-formation were ≳109 M⊙, the ionizing background would be over-produced at z ≲ 5. In summary, our results indicate that the Universe was reionized by low mass galaxies.

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