Conveners
Extragalactic Science: 1
- Kunihito Ioka (Yukawa Institute for Theoretical Physics, Kyoto University)
- Guenter Sigl (University of Hamburg)
- Tova Yoast-Hull (Canadian Institute for Theoretical Astrophysics)
- DI MAURO MATTIA (Stanford University)
Extragalactic Science: 2
- DI MAURO MATTIA (Stanford University)
- Kunihito Ioka (Yukawa Institute for Theoretical Physics, Kyoto University)
- Guenter Sigl (University of Hamburg)
- Tova Yoast-Hull (Canadian Institute for Theoretical Astrophysics)
Extragalactic Science: 3
- DI MAURO MATTIA (Stanford University)
- Tova Yoast-Hull (Canadian Institute for Theoretical Astrophysics)
- Guenter Sigl (University of Hamburg)
- Kunihito Ioka (Yukawa Institute for Theoretical Physics, Kyoto University)
Description
Chair 1: Tova Yoast-Hull | Chair 2: Günter Sigl | Chair 3: Shigeo Kimura
Rafael Alves Batista
(University of São Paulo)
27/08/2018, 16:15
Extragalactic
Talk
In the last decades significant progress has been made towards understanding the origin and nature of ultra-high-energy cosmic rays (UHECRs). However, their sources and composition still remain largely unknown. To interpret the data and find the elusive sources of UHECRs, it is important to understand how cosmic rays propagate in the universe. This is not a trivial task, given our limited...
Dr
Monica Vazquez Acosta
(Instituto de Astrofisica de Canarias)
27/08/2018, 16:35
Extragalactic
Talk
A measurement of the Extragalactic Background Light (EBL) from a combined likelihood analysis of blazar spectra detected by the MAGIC Telescopes is presented. EBL is the optical-infrared diffuse background light accumulated during the history of the Universe, directly emitted (mostly) by stars or reprocessed by dust, providing unique information about the history of galaxy formation. The low...
Dr
Jacek Niemiec
(Institute of Nuclear Physics Polish Academy of Sciences)
27/08/2018, 16:55
Extragalactic
Talk
Collisionless shocks are found in a number of astrophysical objects, ranging in size from the Earth's bow shock through solar flares, termination shock of the solar wind, supernova remnant shocks, and merger shocks in galaxy clusters. In the latter case, low Mach number (Ms << 10) shocks are found propagating in a high beta (β > 1) plasmas, where β is the ratio of thermal to magnetic pressure....
Annika Rudolph
(DESY)
27/08/2018, 17:10
Extragalactic
Talk
Due to the large amounts of energy they release, the luminous
transients called Gamma-Ray Bursts (GRBs) are of great interest for high
energy astroparticle physics. In the fireball internal shock scenario,
the prompt high energy emission is generated in collisions between
regions of the jet with different Lorentz factors. However, the
classical internal shock model faces several...
Dr
Tomohisa Kawashima
(National Astronomical Observatory of Japan)
27/08/2018, 17:25
Extragalactic
Talk
Ultra-luminous X-ray sources (ULXs) are extragalactic, off-nucleus, point-like X-ray sources with enormous luminosity $> 10^{39} ~[{\rm erg}~{\rm s}^{-1}]$, which exceeds the Eddington limit for stellar-mass black holes. Because of such a large luminosity, ULXs are expected to be powered by the super-Eddington accretion onto neutron stars or stellar-mass black holes, or sub-Eddington accretion...
Mr
Shotaro Yamasaki
(University of Tokyo)
27/08/2018, 17:45
Extragalactic
Talk
Most fast radio bursts (FRB) do not show evidence of repetition, and such non-repeating
FRBs may be produced at the time of a merger of binary neutron stars (BNS), provided
that the BNS merger rate is close to the high end of the currently possible range. However,
the merger environment is polluted by dynamical ejecta, which may prohibit the
radio signal from propagating.We examine this by...
Dr
Manuel Meyer
(Stanford University)
29/08/2018, 16:15
Extragalactic
Talk
Almost 10 years of observations with the Fermi Large Area Telescope (LAT) have revealed extreme gamma-ray outbursts from flat spectrum radio quasars (FSRQs), temporarily making these objects the brightest gamma-ray emitters in sky. Yet, the location and mechanisms of the gamma-ray emission remain elusive. Here, we characterize the brightest flares of six FSRQs observed with the LAT. We find...
Dr
Michael Zacharias
(TPIV, Ruhr-Univseristät, Bochum, Germany)
29/08/2018, 16:30
Extragalactic
Talk
In late 2016 and early 2017, the flat spectrum radio quasar CTA 102 (z=1.032) experienced an extraordinary phase of its existence. Starting in October 2016, over the course of two months the gamma-ray flux rose by a factor 50 and decreased again for 2 months to pre-flare levels. This long-term trend has been superposed by short, bright flares, which made CTA 102 one of the brightest gamma-ray...
64.
Intranight variability of VHE gamma-ray emission during the outburst of PKS 1510-089 in May 2016
Dr
Julian Sitarek
(University of Lodz)
29/08/2018, 16:45
Extragalactic
Talk
PKS 1510-089 is one of only a handful of flat spectrum radio quasars
detected in very high energy (VHE, E > 100 GeV) gamma rays. Since the
first detection in 2009, despite showing strong variability in the
optical and GeV range, no VHE gamma-ray variability could be claimed
until a moderate 5-fold increase of the VHE gamma-ray flux was
observed in 2015. In May 2016, a major VHE gamma-ray...
Carlo Romoli
(Max Planck Institute or Nuclear Physics)
29/08/2018, 17:00
Extragalactic
Talk
The FSRQ 3C 279 (z=0.536) is a well known bright variable blazar.
In recent years it has undergone several luminous outbursts
detected at all wavelengths.
Here we highlight the results of H.E.S.S. observations of two types of
events of different nature
during the year 2017 and in January 2018. The first Target of
Opportunity followed
the external trigger from the ATOM optical telescope...
Prof.
Sergey Troitsky
(INR, Moscow)
29/08/2018, 17:15
Extragalactic
Talk
Unphysical distance dependence in convex features of deabsorbed blazar spectra (upward breaks), reported in 2014, suggested incorrect model of absorption of E>100 GeV gamma rays due to e+e- pair production on the extragalactic background light (EBL). We present and interpret results of the new study aimed to constrain EBL in the same approach, making use of an updated clean source sample, new...
Dr
Mikhail Kuznetsov
(INR RAS, Moscow)
29/08/2018, 17:30
Extragalactic
Talk
The Universe is expected to be opaque for gamma rays with TeV energies. However several distant blazars have been observed in TeV region. One possible solution to this puzzle is to assume that the same sources emit cosmic rays towards the Earth and the gamma rays observed are products of line of sight cosmic ray interactions. We examine viability of this scenario in the context of possible...
Mr
Hassan Abdalla
(North-West University)
29/08/2018, 17:45
Extragalactic
Talk
At energies approaching the Planck energy scale $10^{19} GeV$, several quantum-gravity theories predict that familiar concepts such as Lorentz (LIV) symmetry can be broken.
Such extreme energies are currently unreachable by experiments on Earth, but for photons traveling over cosmological distances the accumulated deviations from the Lorentz symmetry may be measurable using the Cherenkov...
Martin Pohl
(DESY)
30/08/2018, 14:00
Extragalactic
Talk
Electromagnetic cascading of TeV-band gamma-ray emission from distant blazars is a means to investigate the amplitude of magnetic field in the voids of intergalactic space. The flux of cascade emission from some objects is weaker than it should be, leaving two interpretation. The magnetic field may be strong enough to deflect the electron-positron pairs out of the line of sight. Alternatively...
Dr
Shriharsh Tendulkar
(McGill University)
30/08/2018, 14:20
Extragalactic
Talk
Fast Radio Bursts (FRBs) are mysterious radio transients that occur at a prodigious rate of $\approx 10^3$ events per day above fluences of 1 Jansky-ms in the entire sky. Arriving from cosmological distances ($\sim$Gpc), FRBs show potential to be novel probes of cosmological parameters, the ionized baryon distribution, and the magnetic fields around and between galaxies. We do not know the...
Mr
Ido Reiss
(Ben Gurion University of the Negev)
30/08/2018, 14:40
Extragalactic
Talk
Galaxy clusters are thought to grow by accreting mass through large scale, strong yet elusive, virial shocks. These collisionless shocks are thought to accelerate relativistic electrons, generating a spectrally-flat leptonic virial ring. However, with the exception of a VERITAS signal from the Coma cluster, attempts to detect virial rings have all failed. By stacking and rescaling Fermi-LAT...
Dr
Felicia Krauss
(GRAPPA/API, UvA)
30/08/2018, 14:55
Extragalactic
Talk
PMN J1603−4904 is only the second confirmed young radio galaxy (compact symmetric object) that has been detected with *Fermi*-LAT. These objects, which may transition into larger radio galaxies, are a stepping stone to understanding AGN and jet evolution. It is not clear how they can produce high-energy γ rays. We present multiwavelength observations, including a spectral energy distribution...
Dr
Tomislav Terzić
(University of Rijeka, Department of Physics)
30/08/2018, 15:10
Extragalactic
Talk
TON 0599 (z=0.7247) is the latest addition to a limited club of flat spectrum radio quasars (FSRQs) detected in very high energy (VHE, E > 100 GeV) gamma rays. Its redshift makes it the third farthest source, filling the gap in the redshift distribution of the VHE gamma ray emitters. It was detected for the first time with the MAGIC telescopes on 2017/12/15. The observations were triggered by...
