# TeVPA 2018

27-31 August 2018
LVH, Luisenstraße 58, 10117 Berlin
Europe/Berlin timezone
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# Gamma Rays

## Place

Location: LVH, Luisenstraße 58, 10117 Berlin
Address: LANGENBECK VIRCHOW HAUS Luisenstraße 58, 10117 Berlin
Date: from 27 Aug 16:15 to 31 Aug 16:02

## Description

Chair 1: Stefan Ohm | Chair 2: Ruben Lopez-Coto | Chair 3: Sara Buson | Chair 4: Felicia Krauss | Chair 5: Francesco Longo | Chair 6: David Sanchez | Chair 7: Konstancja Satalecka

## Conveners

• 27 Aug 16:15 - 5:50 PM 1
• Dr. Lopez-Coto, Ruben (INFN Padova)
• Dr. Buson, Sara (NASA-GSFC)
• Mr. Ohm, Stefan (DESY, Zeuthen)
• 28 Aug 14:00 - 3:45 PM 2
• Dr. Lopez-Coto, Ruben (INFN Padova)
• Dr. Buson, Sara (NASA-GSFC)
• Mr. Ohm, Stefan (DESY, Zeuthen)
• 28 Aug 16:45 - 6:30 PM 3
• Dr. Lopez-Coto, Ruben (INFN Padova)
• Dr. Buson, Sara (NASA-GSFC)
• Mr. Ohm, Stefan (DESY, Zeuthen)
• 29 Aug 14:00 - 3:45 PM 4
• Dr. Lopez-Coto, Ruben (INFN Padova)
• Dr. Buson, Sara (NASA-GSFC)
• Mr. Ohm, Stefan (DESY, Zeuthen)
• 29 Aug 16:15 - 6:05 PM 5
• Dr. Lopez-Coto, Ruben (INFN Padova)
• Dr. Buson, Sara (NASA-GSFC)
• Mr. Ohm, Stefan (DESY, Zeuthen)
• 30 Aug 16:15 - 6:00 PM 6
• Dr. Lopez-Coto, Ruben (INFN Padova)
• Dr. Buson, Sara (NASA-GSFC)
• Mr. Ohm, Stefan (DESY, Zeuthen)
• 31 Aug 14:00 - 4:02 PM 7
• Dr. Lopez-Coto, Ruben (INFN Padova)
• Dr. Buson, Sara (NASA-GSFC)
• Mr. Ohm, Stefan (DESY, Zeuthen)

## Timetable | Contribution List

Displaying 45 contributions out of 45
Type: Talk Session: Gamma Rays
Track: Galactic
In the light of new data regarding the high-energy $\gamma$-ray emission of suspected massive star colliding-wind binary systems, magneto-hydrodynamic simulations can now be refined and adapted in order to provide explanation of past and prediction of future emission characteristics of these sources. We use three-dimensional magneto-hydrodynamic modeling to investigate the structure and condit ... More
Presented by Dr. Klaus REITBERGER on 28/8/2018 at 13:05
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The synchrotron spectrum of the Crab Nebula has long been a mystery: rather than having one cooling break, there are at least two breaks: around 1E14 Hz, and around 1E16 Hz. The spectrum cuts off around 1E21 Hz. The break around 1E14 Hz can be explained by synchrotron cooling, but the second break is rather enigmatic and various explanations have been offered, often involving the presence ... More
Presented by Dr. Jacco VINK on 30/8/2018 at 14:49
Type: Talk Session: Gamma Rays
Track: Gamma-rays
We present the results of a systematic search in the AGILE quick-look database for transient gamma-ray sources above 100 MeV that are temporally and spatially coincident with published high-energy neutrino IceCube events. AGILE is a small scientific mission of the Italian Space Agency (ASI) in cooperation with INAF, INFN, CIFS, and with the participation of several Italian companies and Universi ... More
Presented by Ms. Carlotta PITTORI on 31/8/2018 at 12:00
Type: Talk Session: Gamma Rays
Track: Gamma-rays
We present the Advanced Energetic Pair Telescope (AdEPT) which is being developed as a future NASA/GSFC MIDEX mission to perform high-sensitivity medium-energy (5–200 MeV) astronomy and revolutionary gamma-ray polarization measurements. The enabling technology for AdEPT is a large volume gaseous time projection chamber with high spatial resolution 2-dimentional readout. The accurate 3-dimension ... More
Presented by Dr. Andrey TIMOKHIN on 27/8/2018 at 14:50
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Global properties of the almost one hundred millisecond pulsars (MSPs) detected in gamma-rays by the Fermi Large-Area Telescope remain relatively unknown due to multiple large uncertainties. I present here a extensive Bayesian analysis of both the spatial distribution and luminosity function simultaneously. Distance uncertainties, arising from errors in the parallax measurement or Galactic electro ... More
Presented by Mr. Thomas EDWARDS on 29/8/2018 at 15:35
Type: Talk Session: Gamma Rays
Track: Gamma-rays
A signal of high-energy extraterrestrial neutrinos from unknown source(s) was recently discovered by the IceCube experiment. Neutrinos are always produced together with γ-rays, but the γ-ray flux from extragalactic sources is suppressed due to attenuation in the intergalactic medium. We report a γ-ray excess at high Galactic latitudes starting at energies 300 GeV in the data of the Fermi telesc ... More
Presented by Michael KACHELRIESS on 29/8/2018 at 15:50
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Now we are in the era of multi-messenger astronomy including neutrinos and gravitational waves. However, the observational window for gamma rays between 100 keV to a few tens of MeV is still closed. This energy band can bring a key information on astrophysical phenomena such as the nuclear decaying gamma-ray lines from stellar explosions, e$^-$e$^+$ annihilation line, MeV dark matter and so on. ... More
Presented by Mr. Hiroki YONEDA on 27/8/2018 at 14:35
Type: Talk Session: Gamma Rays
Track: Gamma-rays
MGRO J1908+06 is an unidentified bright TeV source. It has been proposed to be one of the most likely neutrino sources. However, no counterpart of MGRO J1908+06 has been detected at other wavelengths, and its nature remains unknown. PSR J1907+0602 is a 106.6 ms gamma-ray pulsar with high spin down power (∼ 2.8×10^36 erg/s) and is spatially associated with MGRO J1908+06. By analyzing Fermi/LAT ... More
Presented by Dr. Jian LI on 30/8/2018 at 15:40
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The Fermi Large Area Telescope (LAT) has provided the largest sample of solar flares with emission greater than 30 MeV to date. These include the detection of the prompt and the delayed emission, in some cases extending up to ~20 hrs. The LAT detected in gamma-rays also three flares placed behind the limb of the visible part of the Sun. These detections are shedding light on the particle accelerat ... More
Presented by Francesco LONGO on 28/8/2018 at 12:00
Type: Talk Session: Gamma Rays
Track: Gamma-rays
In recent years several space-based instruments have probed the sky in hard X rays (E∼10–100 keV: NuSTAR, Swift, INTEGRAL) and in gamma rays (E∼0.1-1000 GeV: Fermi-LAT, AGILE) with considerable scientific return. On the other hand, the challenging energy band between these regimes has remained mostly unexplored since COMPTEL on CGRO (1991-2000). I will review the proposals for future space-b ... More
Presented by Riccardo RANDO on 27/8/2018 at 14:15
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Observations performed by the Large Area Telescope (LAT) on board of the Fermi Gamma-ray Space Telescope around the IC170922A region revealed a flaring gamma-ray blazar, TXS 0506+056, in spatial and temporal coincidence with the neutrino event detected by the IceCube Neutrino Observatory. Archival searches of other historical, well-reconstructed high-energy neutrino events have revealed further po ... More
Presented by Simone GARRAPPA on 31/8/2018 at 12:17
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The Fermi bubbles (FBs) are two large lobes observed in gamma rays up to 55 degrees above and below the Galactic center. Although the FBs were discovered 8 years ago, their origin is still unknown. Even the process of production of the gamma rays: leptonic inverse Compton scattering or interactions of hadronic cosmic rays with gas, is not yet known. Answering the questions of the origin of the FBs ... More
Presented by Dr. Dmitry MALYSHEV on 29/8/2018 at 15:05
Type: Talk Session: Gamma Rays
Track: Gamma-rays
We report the detection of diffuse gamma-ray emissions towards several massive star clusters in our Galaxy. The detailed spectral and spatial analysis reveal a remarkable constancy of the energy and radial distribution of the cosmic ray density, w(E; r) ~ E^2.3 r^{-1} around these massive star clusters. The 1/r decrement of the CR density with the distance from the star cluster is a distinct si ... More
Presented by Dr. Ruizhi YANG on 28/8/2018 at 14:45
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The Small Magellanic Cloud is the second-nearest star-forming galaxy to our Milky Way at a distance of about 60 kpc with major star-formation episodes at 6 Gyr, 0.7 Gyr and 10 Myr ago. This makes the Small Magellanic Cloud an ideal target to study objects related to young stellar populations over a wide range of age. The Magellanic Clouds are currently the only galaxies for which individual sourc ... More
Presented by Ms. Maria HAUPT on 28/8/2018 at 15:50
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The $\eta$ Carinae binary system hosts one of the most massive stars and has the highest known mass-loss rate. This dense wind encounters the much faster wind expelled by the stellar companion, dissipating mechanical energy in the shock. In these regions, particles are accelerated to very-high-energies via diffusive shock acceleration and subsequently cooled via inverse-Compton and photo-pion prod ... More
Presented by Mr. Matteo BALBO on 28/8/2018 at 12:50
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Some recent studies exposed rather strong statistical evidence of in-vacuo-dispersion-like spectral lags for gamma-ray bursts (GRBs), a linear correlation between time of observation and energy of GRB particles. Those results focused on testing in-vacuo dispersion for the most energetic GRB particles, and in particular only included photons with energy at emission greater than 40 GeV. We here exte ... More
Presented by Mr. Michele RONCO on 31/8/2018 at 12:51
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The catalogue of TeV gamma-ray emitting objects includes about 80 extragalactic sources, among which most are blazars. Only a few of them belong to the class of radio galaxies or misaligned blazars. The latter includes PKS 0625-354, an object that was detected in very high energy gamma rays within only 5.5 hours of H.E.S.S. observations. Along with the H.E.S.S. observations, PKS 0625-354 was ... More
Presented by Dr. Alicja WIERZCHOLSKA on 29/8/2018 at 13:00
Type: Talk Session: Gamma Rays
Track: Gamma-rays
On 22$^{\text{nd}}$ September 2017, a high energy neutrino was detected by the IceCube observatory in spatial coincidence with the blazar TXS 0506+056, which was observed to be flaring in the GeV band by the Fermi-LAT telescope. This coincidence triggered a series of multi-wavelength observations by several telescopes on ground and in space. On 24$^{\text{th}}$ September 2017, the MAGIC telesco ... More
Presented by Luca FOFFANO on 29/8/2018 at 12:45
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Since the detection of non-thermal radio emission from the bow shock of a massive runaway star simple models have predicted high-energy emission from these Galactic sources. In this work we develop a more sophisticated model for the non-thermal emission from massive run-away star bow shocks. The main goal is to establish whether these systems are efficient non-thermal emitters or they are not capa ... More
Presented by Dr. Maria Victoria DEL VALLE on 28/8/2018 at 15:35
Type: Talk Session: Gamma Rays
Track: Gamma-rays
We use a time-dependent numerical model to calculate the prompt GRB emission (spectra and light curves) in GeV/TeV energy range. The emission is modelled by combining a time-dependent radiative code, solving for the electron and photon distributions, with a dynamical code calculating the evolution of the physical conditions in the shocked regions of the outflow. The microphysics parameters and th ... More
Presented by Zeljka BOSNJAK on 31/8/2018 at 13:08
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Since Galactic cosmic rays are observed in the PeV range, at least a few sources that accelerate particles to this energy (“PeVatrons”) should exist. A PeVatron is expected to have a hard, hadronic gamma-ray spectrum that extends to at least tens of TeV without any apparent spectral break or cutoff. High energy (> 100 TeV) gamma ray observations are therefore essential to the study of these c ... More
Presented by Mr. Chad BRISBOIS on 28/8/2018 at 15:05
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Astrophysical sources of high-energy radiation such as AGN and microquasars produce relativistic jets. Particle acceleration in jets is theoretically well-motivated, but direct evidence of acceleration in jets has not been observed above a few TeV. Using 33 months of data from HAWC, we present evidence for the production of gamma rays >10 TeV in the jets of SS 433, one of the most powerful microqu ... More
Presented by Mr. Chang Dong RHO on 28/8/2018 at 13:20
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The High Altitude Water Cherenkov (HAWC) Gamma-ray Observatory in the high mountains of Mexico was completed in March of 2015 and is now giving us a new view of the TeV sky. HAWC is 15 times more sensitive than the previous generation of wide-field EAS gamma-ray instruments and is able to detect the Crab nebula at 5σ with each daily transit. Unlike Imaging Atmospheric Cherenkov Telescopes (IACTs) ... More
Presented by Dr. Henrike FLEISCHHACK on 27/8/2018 at 15:20
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Diffuse TeV emission has been observed by H.E.S.S. in the Galactic Center region, in addition to the GeV gamma rays observed by Fermi. We propose that a population of unresolved millisecond pulsars located around the Galactic Center, suggested as possible candidates for the diffuse Galactic Center excess observed by Fermi, accelerate cosmic rays up to very high energies, and are thus also responsi ... More
Presented by Ms. Claire GUÉPIN on 29/8/2018 at 14:35
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Pulsars are among the most compact Very High Energy photon sources of the universe, but the physics processes behind their emission are not yet fully understood. MAGIC, a system of two Imaging Atmospheric Cherenkov Telescopes located at 2200 m a.s.l. on the Canary Island of La Palma (Spain), has pioneered the field of VHE pulsar physics and continues contributing to the advancement of our under ... More
Presented by Mr. Giovanni CERIBELLA on 30/8/2018 at 14:15
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Recent HAWC observations have found extended TeV emission coincident with the Geminga and Monogem pulsars. In this talk, I will show that these detections have significant implications for our understanding of the TeV gamma-ray sky. First, the spectrum and intensity of these TeV Halos indicates that a large fraction of the pulsar spindown energy is efficiently converted into electron-positron pair ... More
Presented by Dr. Tim LINDEN on 30/8/2018 at 15:23
Type: Talk Session: Gamma Rays
Track: Gamma-rays
LHAASO is a complex of air shower detector arrays under construction. With the detection of muons in air shower, the arrays have strong selection power of VEH-UHE gamma rays out of the CR background. Its wide FoV and continuous operation time will provide a survey sensitivity of 10 mini-Crab-unit over the whole northern sky and monitoring for transient phenomena, such as GRB HE-photons. The differ ... More
Presented by Zhen CAO on 31/8/2018 at 13:42
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The gamma-ray emission in broad-line blazars is generally explained as inverse Compton (IC) radiation of relativistic electrons in the jet scattering optical-UV photons from the broad-line region (BLR), the so-called BLR external Compton (EC) scenario. We test this scenario on the Fermi gamma-ray spectra of 106 broad-line blazars detected with the highest significance or largest BLR, by looking fo ... More
Presented by Dr. Sara CUTINI on 29/8/2018 at 12:15
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Eta Car is a colliding-wind binary composed of a massive luminous blue variable (~100 solar masses) and a companion star of O or B-type (~ 30 solar masses). Its orbit is very eccentric and has a period of 2023 days. Although the binary has a rich observational history in, e.g. the optical regime, strong experimental evidence for gamma-ray emission from the system has built up only recently. It is ... More
Presented by Eva LESER on 28/8/2018 at 12:35
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Recent analyses of the gamma-ray flux from Arp 220 have shown that the observed gamma-ray flux is larger than can be accounted for by the measured star formation rate. In contrast, the radio spectra observed for the galaxy's two nuclei are consisted with the observed rate. This indicates an excess of cosmic rays or additional cosmic ray population which produces more gamma-ray emission but not m ... More
Presented by Tova YOAST-HULL on 28/8/2018 at 16:05
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The Crab nebula is a bright emitter of non-thermal radiation across the entire accessible range of wavelengths. The spatial and spectral structures of the synchrotron nebula are well-resolved from radio to hard X-ray emission. The un-pulsed emission at GeV to TeV energies is mostly produced via inverse-Compton scattering of energetic electrons with the synchrotron-emitted photons. The spatial str ... More
Presented by Mr. Paul Kin-Hang YEUNG on 30/8/2018 at 14:32
Type: Talk Session: Gamma Rays
Track: Gamma-rays
A persistent excess of gamma rays measured with the Fermi-LAT has been found towards the center of the Galaxy, typically referred to as the Galactic Center Excess (GCE). While its existence is well established, its nature and origin are still debated. While a simple but exotic origin for the GCE could be the annihilation of dark matter, other astrophysical origins, such as emission from millisecon ... More
Presented by Emma STORM on 29/8/2018 at 14:50
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The Fermi bubbles (FBs) are two giant gamma-ray lobes above and below the Galactic center. Their origin is not clear yet and both hadronic and leptonic models are currently allowed. In the hadronic model, the acceleration of protons and/or nuclei and their subsequent interactions with gas in the bubble volume can produce the observed gamma rays and high-energy neutrinos as counterparts. The detect ... More
Presented by Ms. Lili YANG, Prof. Soebur RAZZAQUE on 29/8/2018 at 15:20
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Previous analyses of point sources in the gamma-ray range were done only below 30 MeV (COMPTEL) or above 100 MeV (Fermi-Large Area Telescope). Below 30 MeV, the imaging Compton telescope (COMPTEL) detected 26 steady sources in the energy range from 0.75 to 30 MeV. At high energy, the LAT detects more than three thousand sources between 100 MeV and 300 GeV (3FGL). Since the Fermi-LAT detects gamma ... More
Presented by Mr. Giacomo PRINCIPE on 29/8/2018 at 12:00
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The Galactic Center (GC) hosts a Super-Massive Black Hole (SMBH) of 4*10^6 Msun, Sgr A*, which has apparently experienced phases of quasar activity in the past and might accelerate particles up to very high energy. The inner 150 pc also harbor intense star formation activity and many Supernova Remnants and Pulsar Wind Nebulae which must also be the site of sustained particle acceleration. At GeV ... More
Presented by Dr. ANNE LEMIERE on 29/8/2018 at 14:15
Type: Talk Session: Gamma Rays
Track: Gamma-rays
In the past 15 years the H.E.S.S. collaboration has intensively surveyed the inner region of our own galaxy, the Milky Way. These observations have culminated in a recent release of 14 publications in a dedicated issue of Astronomy & Astrophysics. In this talk we will present the core part of this programme, the H.E.S.S. Galactic Plane Survey (HGPS), which yielded a catalog of 78 gamma-ray sou ... More
Presented by David BERGE on 30/8/2018 at 15:06
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The Tunka Advanced Instrument for cosmic ray and Gamma ray Astrophysics, TAIGA, aims at accessing the gamma-ray sky in the multi-TeV to PeV energy regime. This energy range is key to spectroscopically resolving the cutoff regime of the - yet to be identified - Galactic cosmic ray Pevatrons. Sensitive gamma-ray observations in this energy range are essential for this task, and require a very large ... More
Presented by Martin TLUCZYKONT on 31/8/2018 at 13:25
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Fabian Schüssler for the CTA consortium The Cherenkov Telescope Array (CTA) is the next generation high-energy gamma-ray observatory using the Imaging Air Cherenkov Telescope (IACT) technique. It will improve the sensitivity level of current instruments by an order of magnitude, provide energy coverage for photons from 20 GeV to at least 300 TeV to reach to high redshifts and extreme accelerat ... More
Presented by Dr. Fabian SCHUSSLER on 27/8/2018 at 15:35
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Very high-energy gamma-rays from TeV blazars interact with the extragalactic background light producing pair beams. These pairs emit secondary photons in the GeV range by the inverse Compton scattering. However, the measured GeV signal is smaller compared to one predicted from the full electromagnetic cascade. From what follows that the pairs are affected by some other physical processes leading t ... More
Presented by Dr. Sergei VAFIN on 29/8/2018 at 13:30
Type: Talk Session: Gamma Rays
Track: Gamma-rays
I will discuss recent results on gamma-ray observations of the Sun with Fermi, which revealed many interesting and surprising features. These gamma rays are expected to be produced by hadronic interactions between cosmic rays and the solar atmosphere. The high flux of gamma rays observed from the Sun requires a large boost of gamma-ray production by some mechanism, which is likely related to sola ... More
Presented by Dr. Ng KENNY CHUN YU on 28/8/2018 at 12:20
Type: Talk Session: Gamma Rays
Track: Gamma-rays
High-energy gamma rays of interstellar origin are produced by the interaction of cosmic-ray (CR) particles with the diffuse gas and radiation fields in the Galaxy. The main features of this emission are well-understood and are reproduced by existing CR propagation models employing 2D Galactocentric cylindrically symmetrical geometry. However, the high-quality data from instruments like the Fermi L ... More
Presented by Dr. Troy PORTER on 28/8/2018 at 15:20
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Emission of distant (redshift z>0.1) extragalactic sources in the GeV-TeV energy range may be significantly transformed during the propagation between the source and the observer. So far, the only robust result in this area was the firm establishment of the existence of the \gamma\gamma\rightarrow e^{+}e^{-} pair production process. During the last 8 years, there were many other claims that were u ... More
Presented by Timur DZHATDOEV on 31/8/2018 at 12:34
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Analysis and combination of data from different gamma-ray instruments involves the use of collaboration proprietary software and case-by-case methods. By defining a common open format for high-level gamma-ray data (containing event lists and instrument response functions, using the FITS standard) we allow multi-instrument analysis within the context of open-source software. This project ... More
Presented by Mr. Cosimo NIGRO on 27/8/2018 at 15:05
Type: Talk Session: Gamma Rays
Track: Gamma-rays
Because of their brightness and proximity (z=0.03), Mrk421 and Mrk501 are among the very-high-energy gamma-ray objects that can be studied with the greatest level of detail. This makes them excellent astrophysical high-energy physics laboratories to study the nature of blazars. Since 2009, there has been an unprecedentedly long and dense monitoring of the radio to very-high-energy gamma-ray emiss ... More
Presented by David PANEQUE on 29/8/2018 at 12:30
Type: Talk Session: Gamma Rays
Track: Gamma-rays
The spectrum of UHECR signal events above 55 EeV from Centaurus A (Cen A) can provide a useful hint about the injected spectrum of cosmic ray nuclei. The injected spectrum connects UHECRs to the HESS detected GeV-TeV gamma rays. The 8 years of Fermi-LAT data from Cen A has significant hardening in the GeV energy. In an attempt to understand the origin of this hardening, we explore two emitting zon ... More
Presented by Dr. Jagdish JOSHI on 29/8/2018 at 13:15
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