727 citations · 2.6k across the 46 of their papers we have counts for
48 papers
Spectro-Polarimetric Observations of TeV Sources (SPOTS): First results
J. Barnard, B. van Soelen, I. P. van der Westhuizen +5
Blazars are jetted active galactic nuclei, with the jet aligned along the observer's line of sight. Their spectral energy distributions are dominated by non-thermal emission, with…
The High Energy X-ray Probe (HEX-P): the most powerful jets through the lens of a superb X-ray eye
Lea Marcotulli, Marco Ajello, Markus Böttcher +20
A fraction of the active supermassive black holes at the centers of galaxies in our Universe are capable of launching extreme kiloparsec-long relativistic jets. These jets are know…
The Compton Spectrometer and Imager
John A. Tomsick, Steven E. Boggs, Andreas Zoglauer +72
The Compton Spectrometer and Imager (COSI) is a NASA Small Explorer (SMEX) satellite mission in development with a planned launch in 2027. COSI is a wide-field gamma-ray telescope…
Spectropolarimetry and photometry of the early afterglow of the gamma-ray burst GRB191221B
D. A. H. Buckley, S. Bagnulo, R. J. Britto +27
We report on results of spectropolarimetry of the afterglow of the long gamma-ray burst GRB 191221B, obtained with SALT/RSS and VLT/FORS2, as well as photometry from two telescopes…
Gamma-ray blazar spectra with H.E.S.S. II mono analysis: the case of PKS 2155-304 and PG 1553+113
D. Zaborov, A. M. Taylor, D. A. Sanchez +2
The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies, providing new opportunities for studies of Active Ga…
Gamma-ray blazar spectra with H.E.S.S. II mono analysis: the case of PKS 2155-304 and PG 1553+113
H. E. S. S. Collaboration, :, H. Abdalla +332
The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies. The lowest energy threshold is obtained using monosc…
Robopol: Optical polarisation monitoring of blazars
Emmanouil Angelakis, Dmitry Blinov, Markus Böttcher +5
The RoboPol program has been monitoring the -band linear polarisation parameters of an unbiased sample of 60 gamma-ray-loud blazars and a "control" sample of 15 gamma-ray-quite…
Theoretical Study Of The Effects Of Magnetic Field Geometry On The High-Energy Emission Of Blazars
Manasvita Joshi, Alan P. Marscher, Markus Boettcher
The knowledge of the structure of the magnetic field inside a blazar jet, as deduced from polarization observations at radio to optical wavelengths, is closely related to the forma…
Gravitational Light Bending Prevents Absorption in Gravitational Lenses
Markus Boettcher, Hannes Thiersen
The magnification effect due to gravitational lensing enhances the chances of detecting moderate-redshift () sources in very-high-energy (VHE; GeV) -rays by…
RoboPol: The optical polarization of gamma-ray--loud and gamma-ray--quiet blazars
E. Angelakis, T. Hovatta, D. Blinov +25
We present average R-band optopolarimetric data, as well as variability parameters, from the first and second RoboPol observing season. We investigate whether gamma- ray--loud and…
High Energy Emission from Black Widows and Redbacks
Zorawar Wadiasingh, Alice K. Harding, Christo Venter +1
A large number of new black widow and redback energetic millisecond pulsars with irradiated stellar companions have been discovered through radio searches of unidentified \emph{Fer…
Polarization Signatures of Relativistic Magnetohydrodynamic Shocks in the Blazar Emission Region - I. Force-free Helical Magnetic Fields
Haocheng Zhang, Wei Deng, Hui Li +1
The optical radiation and polarization signatures in blazars are known to be highly variable during flaring activities. It is frequently argued that shocks are the main driver of t…
Role of the disk environment in the gamma-ray emission from the binary system PSR B1259-63/LS 2883
Iurii Sushch, Markus Böttcher
PSR B1259-63/LS 2883 is a very high energy (VHE; E > 100 GeV) gamma-ray emitting binary consisting of a 48 ms pulsar orbiting around a Be star with a period of 3.4 years. The Be st…
Violent Hard X-ray Variability of Mrk 421 Observed by NuSTAR in 2013 April
Vaidehi S. Paliya, Markus Bottcher, Chris Diltz +3
The well studied blazar Markarian 421 (Mrk 421, =0.031) was the subject of an intensive multi-wavelength campaign when it flared in 2013 April. The recorded X-ray and very high…
Multi-wavelength study of flaring activity in BL Lac object S5 0716+714 during 2015 outburst
Sunil Chandra, Haocheng Zhang, Pankaj Kushwaha +4
We present a detailed investigation of the flaring activity observed from a BL Lac object, S5 0716+714 , during its brightest ever optical state in the second half of January 2015.…
Discovery of variable VHE gamma-ray emission from the binary system 1FGL J1018.6-5856
H. E. S. S. Collaboration, :, A. Abramowski +230
Re-observations with the H.E.S.S. telescope array of the very-high-energy (VHE) source HESS J1018-589 A coincident with the Fermi-LAT -ray binary 1FGL J1018.6-5856 have resulted…
Studies of Relativistic Jets in Active Galactic Nuclei with SKA
Ivan Agudo, Markus Boettcher, Heino Falcke +19
Relativistic jets in active galactic nuclei (AGN) are among the most powerful astrophysical objects discovered to date. Indeed, jetted AGN studies have been considered a prominent…
Hadronic models of blazars require a change of the accretion paradigm
Andrzej A. Zdziarski, Markus Boettcher
We study hadronic models of broad-band emission of jets in radio-loud active galactic nuclei, and their implications for the accretion in those sources. We show that the models tha…
The Polarization Dependence of Gamma-Gamma Absorption - Implications for Gamma-Ray Bursts and Blazars
Markus Boettcher
This paper presents an analysis of the dependence of the opacity for high-energy gamma-rays to gamma-gamma absorption by low-energy photons, on the polarization of the gamma-ray an…
Magnetic Field Amplification and Flat Spectrum Radio Quasars
Xuhui Chen, Ritaban Chatterjee, Haocheng Zhang +10
We perform time-dependent, spatially-resolved simulations of blazar emission to evaluate several flaring scenarios related to magnetic-field amplification and enhanced particle acc…
Leptonic and Hadronic Modeling of Fermi-Detected Blazars
M. Boettcher, A. Reimer, K. Sweeney +1
We describe new implementations of leptonic and hadronic models for the broadband emission from relativistic jets in AGN in a temporary steady state. For the leptonic model, a temp…
Radio-Optical-Gamma-Ray properties of MOJAVE AGN detected by Fermi/LAT
T. G. Arshakian, J. León-Tavares, M. Boettcher +5
Aims. We use a sample of 83 core-dominated active galactic nuclei (AGN) selected from the MOJAVE (Monitoring of Jets in AGN with VLBA Experiments) radio-flux-limited sample and det…
X-Ray Spectral Variability Signatures of Flares in BL Lac Objects
M. Boettcher, J. Chiang
We are presenting a detailed parameter study of the time-dependent electron injection and kinematics and the self-consistent radiation transport in jets of intermediate and low-fre…
Predictions of the High-Energy Emission from BL Lac objects: The Case of W Comae
M. Boettcher, R. Mukherjee, A. Reimer
Spectral fitting of the radio through hard X-ray emission of BL Lac objects has previously been used to predict their level of high-energy (GeV - TeV) emission. In this paper, we p…