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Prokhorov, DmitryORCID iD iconorcid.org/0000-0001-6511-4330
Publications (10 of 52) Show all publications
Abdallah, H., Adam, R., Aharonian, F., Benkhali, F. A., Anguner, E. O., Arakawa, M., . . . Zywucka, N. (2020). Search for dark matter signals towards a selection of recently detected DES dwarf galaxy satellites of the Milky Way with HESS. Physical Review D: covering particles, fields, gravitation, and cosmology, 102(6), 1-20, Article ID 062001.
Open this publication in new window or tab >>Search for dark matter signals towards a selection of recently detected DES dwarf galaxy satellites of the Milky Way with HESS
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2020 (English)In: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 102, no 6, p. 1-20, article id 062001Article in journal (Refereed) Published
Abstract [en]

Dwarf spheroidal galaxy satellites of the Milky Way are prime targets for indirect detection of dark matter with gamma rays due to their proximity, high dark matter content, and absence of nonthermal emission processes. Recently, the Dark Energy Survey (DES) revealed the existence of new ultrafaint dwarf spheroidal galaxies in the southern-hemisphere sky, therefore ideally located for ground-based observations with the imaging atmospheric Cherenkov telescope array H.E.S.S. We present a search for very-high-energy (E greater than or similar to 100 GeV) gamma-ray emission using H.E.S.S. observations carried out recently towards Reticulum II, Tucana II, Tucana III, Tucana IV, and Grus II satellites. No significant very-high-energy gamma-ray excess is found from the observations on any individual object nor in the combined analysis of all the datasets. Using the most recent modeling of the dark matter distribution in the dwarf galaxy halo, we compute for the first time on DES satellites individual and combined constraints from Cherenkov telescope observations on the annihilation cross section of dark matter particles in the form of Weakly Interacting Massive Particles. The combined 95% C.L. observed upper limits reach <sigma v > similar or equal to 1 x 10(-23) cm(3) s(-1) in the W+W- channel and 4 x 10(-26) cm(3) s(-1) in the gamma gamma channels for a dark matter mass of 1.5 TeV. The H.E.S.S. constraints well complement the results from Fermi-LAT, HAWC, MAGIC, and VERITAS and are currently the most stringent in the gamma gamma channels in the multi-GeV/multi-TeV mass range.
Place, publisher, year, edition, pages
American Physical Society, 2020
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Physics, Astroparticle Physics
Identifiers
urn:nbn:se:lnu:diva-98262 (URN)10.1103/PhysRevD.102.062001 (DOI)000565085500001 ()2-s2.0-85096289178 (Scopus ID)
Available from: 2020-10-06 Created: 2020-10-06 Last updated: 2025-05-09Bibliographically approved
Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. A., Akhperjanian, A. G., Andersson, T., . . . Yoshiike, S. (2018). A search for new supernova remnant shells in the Galactic plane with HESS. Astronomy and Astrophysics, 612, Article ID A8.
Open this publication in new window or tab >>A search for new supernova remnant shells in the Galactic plane with HESS
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2018 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 612, article id A8Article in journal (Refereed) Published
Abstract [en]

A search for new supernova remnants (SNRs) has been conducted using TeV gamma-ray data from the H.E.S.S. Galactic plane survey. As an identification criterion, shell morphologies that are characteristic for known resolved TeV SNRs have been used. Three new SNR candidates were identified in the H.E.S.S. data set with this method. Extensive multiwavelength searches for counterparts were conducted. A radio SNR candidate has been identified to be a counterpart to HESS J1534-571. The TeV source is therefore classified as a SNR. For the other two sources, HESS J1614-518 and HESS J1912 + 101, no identifying counterparts have been found, thus they remain SNR candidates for the time being. TeV-emitting SNRs are key objects in the context of identifying the accelerators of Galactic cosmic rays. The TeV emission of the relativistic particles in the new sources is examined in view of possible leptonic and hadronic emission scenarios, taking the current multiwavelength knowledge into account.
Place, publisher, year, edition, pages
EDP Sciences, 2018
Keywords
astroparticle physics, ISM: supernova remnants, cosmic rays
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Physics, Astroparticle Physics
Identifiers
urn:nbn:se:lnu:diva-76475 (URN)10.1051/0004-6361/201730737 (DOI)000429404700008 ()2-s2.0-85045527248 (Scopus ID)
Available from: 2018-07-10 Created: 2018-07-10 Last updated: 2025-03-27Bibliographically approved
Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. A., Akhperjanian, A. G., Angüner, E. O., . . . Zywucka, N. (2018). A search for very high-energy flares from the microquasars GRS 1915+105, Circinus X-1, and V4641 Sgr using contemporaneous HESS and RXTE observations. Astronomy and Astrophysics, 612, Article ID A10.
Open this publication in new window or tab >>A search for very high-energy flares from the microquasars GRS 1915+105, Circinus X-1, and V4641 Sgr using contemporaneous HESS and RXTE observations
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2018 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 612, article id A10Article in journal (Refereed) Published
Abstract [en]

Context. Microquasars are potential gamma-ray emitters. Indications of transient episodes of gamma-ray emission were recently reported in at least two systems: Cyg X-1 and Cyg X-3. The identification of additional gamma-ray-emitting microquasars is required to better understand how gamma-ray emission can be produced in these systems. Aims. Theoretical models have predicted very high-energy (VHE) gamma-ray emission from microquasars during periods of transient outburst. Observations reported herein were undertaken with the objective of observing a broadband flaring event in the gamma-ray and X-ray bands. Methods. Contemporaneous observations of three microquasars, GRS 1915+105, Circinus X-1, and V4641 Sgr, were obtained using the High Energy Spectroscopic System (H.E.S.S.) telescope array and the Rossi X-ray Timing Explorer (RXTE) satellite. X-ray analyses for each microquasar were performed and VHE gamma-ray upper limits from contemporaneous H.E.S.S. observations were derived. Results. No significant gamma-ray signal has been detected in any of the three systems. The integral gamma-ray photon flux at the observational epochs is constrained to be I(>560 GeV) < 7.3 x 10(-13) cm(-2) S-1, I(>560 GeV) < 1.2 x 10-(12) cm s(-1), and I(>240 GeV) < 4.5 x 10(-12) cm(-2) s(-1) for GRS 1915+105, Circinus X-1, and V4641 Sgr, respectively. Conclusions. The gamma-ray upper limits obtained using H.E.S.S. are examined in the context of previous Cherenkov telescope observations of microquasars. The effect of intrinsic absorption is modelled for each target and found to have negligible impact on the flux of escaping gamma-rays. When combined with the X-ray behaviour observed using RXTE, the derived results indicate that if detectable VHE gamma-ray emission from microquasars is commonplace, then it is likely to be highly transient.
Place, publisher, year, edition, pages
EDP Sciences, 2018
Keywords
gamma rays: general, X-rays: binaries, X-rays: individuals: GRS 1915+105, X-rays: individuals: Circinus X-1, X-rays: individuals: V4641 Sgr
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Physics, Astroparticle Physics
Identifiers
urn:nbn:se:lnu:diva-76466 (URN)10.1051/0004-6361/201527773 (DOI)000429404700010 ()2-s2.0-85045528971 (Scopus ID)
Available from: 2018-07-10 Created: 2018-07-10 Last updated: 2025-03-11Bibliographically approved
Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. A., Akhperjanian, A. G., Andersson, T., . . . Zywucka, N. (2018). Characterising the VHE diffuse emission in the central 200 parsecs of our Galaxy with HESS. Astronomy and Astrophysics, 612, Article ID A9.
Open this publication in new window or tab >>Characterising the VHE diffuse emission in the central 200 parsecs of our Galaxy with HESS
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2018 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 612, article id A9Article in journal (Refereed) Published
Abstract [en]

The diffuse very high-energy (VHE; > 100 GeV) gamma-ray emission observed in the central 200 pc of the Milky Way by H.E.S.S. was found to follow dense matter distribution in the central molecular zone (CMZ) up to a longitudinal distance of about 130 pc to the Galactic centre (GC), where the flux rapidly decreases. This was initially interpreted as the result of a burst-like injection of energetic particles 104 yr ago, but a recent more sensitive H.E.S.S. analysis revealed that the cosmic-ray (CR) density profile drops with the distance to the centre, making data compatible with a steady cosmic PeVatron at the GC. In this paper, we extend this analysis to obtain, for the first time, a detailed characterisation of the correlation with matter and to search for additional features and individual gamma-ray sources in the inner 200 pc. Taking advantage of 250 h of H.E.S.S. data and improved analysis techniques, we perform a detailed morphology study of the diffuse VHE emission observed from the GC ridge and reconstruct its total spectrum. To test the various contributions to the total gamma-ray emission, we used an iterative 2D maximum-likelihood approach that allows us to build a phenomenological model of the emission by summing a number of different spatial components. We show that the emission correlated with dense matter covers the full CMZ and that its flux is about half the total diffuse emission flux. We also detect some emission at higher latitude that is likely produced by hadronic collisions of CRs in less dense regions of the GC interstellar medium. We detect an additional emission component centred on the GC and extending over about 15 pc that is consistent with the existence of a strong CR density gradient and confirms the presence of a CR accelerator at the very centre of our Galaxy. We show that the spectrum of full ridge diffuse emission is compatible with that previously derived from the central regions, suggesting that a single population of particles fills the entire CMZ. Finally, we report the discovery of a VHE gamma-ray source near the GC radio arc and argue that it is produced by the pulsar wind nebula candidate G0.13-0.11.
Place, publisher, year, edition, pages
EDP Sciences, 2018
Keywords
gamma rays: general, gamma rays: ISM, Galaxy: center, cosmic rays
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Physics, Astroparticle Physics
Identifiers
urn:nbn:se:lnu:diva-76467 (URN)10.1051/0004-6361/201730824 (DOI)000429404700009 ()2-s2.0-85045525369 (Scopus ID)
Available from: 2018-07-10 Created: 2018-07-10 Last updated: 2025-03-11Bibliographically approved
Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Arcaro, C., Babie, A., Banerjee, B., . . . Prokoph, H. (2018). Constraints on particle acceleration in SS433/W50 from MAGIC and HESS observations. Astronomy and Astrophysics, 612, Article ID A14.
Open this publication in new window or tab >>Constraints on particle acceleration in SS433/W50 from MAGIC and HESS observations
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2018 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 612, article id A14Article in journal (Refereed) Published
Abstract [en]

Context. The large jet kinetic power and non-thermal processes occurring in the microquasar SS 433 make this source a good candidate for a very high-energy (VHE) gamma-ray emitter. Gamma-ray fluxes above the sensitivity limits of current Cherenkov telescopes have been predicted for both the central X-ray binary system and the interaction regions of SS 433 jets with the surrounding W50 nebula. Non-thermal emission at lower energies has been previously reported, indicating that efficient particle acceleration is taking place in the system. Aims. We explore the capability of SS 433 to emit VHE gamma rays during periods in which the expected flux attenuation due to periodic eclipses (P-orb similar to 13.1 days) and precession of the circumstellar disk (P-pre similar to 162 days) periodically covering the central binary system is expected to be at its minimum. The eastern and western SS 433/W50 interaction regions are also examined using the whole data set available. We aim to constrain some theoretical models previously developed for this system with our observations. Methods. We made use of dedicated observations from the Major Atmospheric Gamma Imaging Cherenkov telescopes (MAGIC) and High Energy Spectroscopic System (H.E.S.S.) of SS 433 taken from 2006 to 2011. These observation were combined for the first time and accounted for a total effective observation time of 16.5 h, which were scheduled considering the expected phases of minimum absorption of the putative VHE emission. Gamma-ray attenuation does not affect the jet/medium interaction regions. In this case, the analysis of a larger data set amounting to similar to 40-80 h, depending on the region, was employed. Results. No evidence of VHE gamma-ray emission either from the central binary system or from the eastern/western interaction regions was found. Upper limits were computed for the combined data set. Differential fluxes from the central system are found to be less than or similar to 10(-12)-10(-13) TeV-1 cm(-2) s(-1) in an energy interval ranging from similar to few x 100 GeV to similar to few TeV. Integral flux limits down to similar to 10(-12)-10(-13) ph cm(-2) s(-1) and similar to 10(-13)-10(-14) ph cm(-2) s(-1) are obtained at 300 and 800 GeV, respectively. Our results are used to place constraints on the particle acceleration fraction at the inner jet regions and on the physics of the jet/medium interactions. Conclusions. Our findings suggest that the fraction of the jet kinetic power that is transferred to relativistic protons must be relatively small in SS 433, q(p) <= 2.5 x 10(-5), to explain the lack of TeV and neutrino emission from the central system. At the SS 433/W50 interface, the presence of magnetic fields greater than or similar to 10 mu G is derived assuming a synchrotron origin for the observed X-ray emission. This also implies the presence of high-energy electrons with E-e up to 50 TeV, preventing an efficient production of gamma-ray fluxes in these interaction regions.
Place, publisher, year, edition, pages
EDP Sciences, 2018
Keywords
gamma rays: general, stars: black holes, X-rays: binaries, ISM: jets and outflows
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Physics, Astroparticle Physics
Identifiers
urn:nbn:se:lnu:diva-76478 (URN)10.1051/0004-6361/201731169 (DOI)000429404700014 ()2-s2.0-85045527587 (Scopus ID)
Available from: 2018-07-10 Created: 2018-07-10 Last updated: 2025-03-27Bibliographically approved
Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. A., Akhperjanian, A. G., Angüner, E. O., . . . Zywucka, N. (2018). Deeper HESS observations of Vela Junior (RX J0852.0-4622): Morphology studies and resolved spectroscopy. Astronomy and Astrophysics, 612, Article ID A7.
Open this publication in new window or tab >>Deeper HESS observations of Vela Junior (RX J0852.0-4622): Morphology studies and resolved spectroscopy
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2018 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 612, article id A7Article in journal (Refereed) Published
Abstract [en]

Aims. We study gamma-ray emission from the shell-type supernova remnant (SNR) RXJ0852.0-4622 to better characterize its spectral properties and its distribution over the SNR. Methods. The analysis of an extended High Energy Spectroscopic System (H.E.S.S.) data set at very high energies (E > 100 GeV) permits detailed studies, as well as spatially resolved spectroscopy, of the morphology and spectrum of the whole RXJ0852.0-4622 region. The H.E.S.S. data are combined with archival data from other wavebands and interpreted in the framework of leptonic and hadronic models. The joint Fermi-LAT-H.E.S.S. spectrum allows the direct determination of the spectral characteristics of the parent particle population in leptonic and hadronic scenarios using only GeV-TeV data. Results. An updated analysis of the H.E.S.S. data shows that the spectrum of the entire SNR connects smoothly to the high-energy spectrum measured by Fermi-LAT. The increased data set makes it possible to demonstrate that the H.E.S.S. spectrum deviates significantly from a power law and is well described by both a curved power law and a power law with an exponential cutoff at an energy of E-cut = (6.7 +/- 1.2(stat) +/- 1.2(syst)) TeV. The joint Fermi-LAT-H.E.S.S. spectrum allows the unambiguous identification of the spectral shape as a power law with an exponential cutoff. No significant evidence is found for a variation of the spectral parameters across the SNR, suggesting similar conditions of particle acceleration across the remnant. A simple modeling using one particle population to model the SNR emission demonstrates that both leptonic and hadronic emission scenarios remain plausible. It is also shown that at least a part of the shell emission is likely due to the presence of a pulsar wind nebula around PSR J0855-4644.
Place, publisher, year, edition, pages
EDP Sciences, 2018
Keywords
astroparticle physics, gamma rays: general, acceleration of particles, cosmic rays, ISM: supernova remnants
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Physics, Astroparticle Physics
Identifiers
urn:nbn:se:lnu:diva-76465 (URN)10.1051/0004-6361/201630002 (DOI)000429404700007 ()2-s2.0-85045509704 (Scopus ID)
Available from: 2018-07-10 Created: 2018-07-10 Last updated: 2025-03-13Bibliographically approved
Abramowski, A., Aharonian, F., Benkhali, F. A., Akhperjanian, A. G., Angüner, E. O., Backes, M., . . . Zywucka, N. (2018). Detailed spectral and morphological analysis of the shell type supernova remnant RCW 86. Astronomy and Astrophysics, 612, Article ID A4.
Open this publication in new window or tab >>Detailed spectral and morphological analysis of the shell type supernova remnant RCW 86
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2018 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 612, article id A4Article in journal (Refereed) Published
Abstract [en]

Aims. We aim for an understanding of the morphological and spectral properties of the supernova remnant RCW 86 and for insights into the production mechanism leading to the RCW 86 very high-energy gamma-ray emission. Methods. We analyzed High Energy Spectroscopic System (H.E.S.S.) data that had increased sensitivity compared to the observations presented in the RCW 86 H.E.S.S. discovery publication. Studies of the morphological correlation between the 0.5-1 keV X-ray band, the 2-5 keV X-ray band, radio, and gamma-ray emissions have been performed as well as broadband modeling of the spectral energy distribution with two different emission models. Results. We present the first conclusive evidence that the TeV gamma-ray emission region is shell-like based on our morphological studies. The comparison with 2-5 keV X-ray data reveals a correlation with the 0.4-50 TeV gamma-ray emission. The spectrum of RCW 86 is best described by a power law with an exponential cutoff at E-cut = (3.5 +/- 1.2(stat)) TeV and a spectral index of Gamma approximate to 1.6 +/- 0.2. A static leptonic one-zone model adequately describes the measured spectral energy distribution of RCW 86, with the resultant total kinetic energy of the electrons above 1 GeV being equivalent to similar to 0.1% of the initial kinetic energy of a Type Ia supernova explosion (10(51) erg). When using a hadronic model, a magnetic field of B approximate to 100 mu G is needed to represent the measured data. Although this is comparable to formerly published estimates, a standard E-2 spectrum for the proton distribution cannot describe the gamma-ray data. Instead, a spectral index of Gamma(p) approximate to 1.7 would be required, which implies that similar to 7 x 10(49)/n(cm-3) erg has been transferred into high-energy protons with the effective density n(cm-3) = n/1 cm(-3). This is about 10% of the kinetic energy of a typical Type Ia supernova under the assumption of a density of 1 cm(-3).
Place, publisher, year, edition, pages
EDP Sciences, 2018
Keywords
astroparticle physics, gamma rays: general, ISM: supernova remnants, cosmic rays
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Physics, Astroparticle Physics
Identifiers
urn:nbn:se:lnu:diva-76477 (URN)10.1051/0004-6361/201526545 (DOI)000429404700004 ()2-s2.0-85006355377 (Scopus ID)
Available from: 2018-07-10 Created: 2018-07-10 Last updated: 2025-03-12Bibliographically approved
Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. A., Akhperjanian, A. G., Angüner, E. O., . . . Zywucka, N. (2018). Extended VHE gamma-ray emission towards SGR1806-20, LBV 1806-20, and stellar cluster Cl*1806-20. Astronomy and Astrophysics, 612, Article ID A11.
Open this publication in new window or tab >>Extended VHE gamma-ray emission towards SGR1806-20, LBV 1806-20, and stellar cluster Cl*1806-20
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2018 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 612, article id A11Article in journal (Refereed) Published
Abstract [en]

Using the High Energy Spectroscopic System (H.E.S.S.) telescopes we have discovered a steady and extended very high-energy (VHE) gamma-ray source towards the luminous blue variable candidate LBV 1806-20, massive stellar cluster Cl* 1806-20, and magnetar SGR 1806-20. The new VHE source, HESS J1808-204, was detected at a statistical significance of >6 sigma (post-trial) with a photon flux normalisation (2.9 +/- 0.4(stat) +/- 0.5(sys)) x 10(-13) ph cm(-2) s(-1) TeV-1 at 1 TeV and a power-law photon index of 2.3 +/- 0.2(stat) +/- 0.3(sys). The luminosity of this source (0.2 to 10 TeV; scaled to distance d = 8 : 7 kpc) is L-VHE similar to 1.6 x 10(34)(d = 8.7 kpc)(2) erg s(-1). The VHE gamma-ray emission is extended and is well fit by a single Gaussian with statistical standard deviation of 0.095 degrees +/- 0.015 degrees. This extension is similar to that of the synchrotron radio nebula G10.0-0.3, which is thought to be powered by LBV 1806-20. The VHE gamma-ray luminosity could be provided by the stellar wind luminosity of LBV 1806-20 by itself and/or the massive star members of Cl* 1806-20. Alternatively, magnetic dissipation (e.g. via reconnection) from SGR 1806-20 can potentially account for the VHE luminosity. The origin and hadronic and/or leptonic nature of the accelerated particles responsible for HESS J1808-204 is not yet clear. If associated with SGR 1806 20, the potentially young age of the magnetar (650 yr) can be used to infer the transport limits of these particles to match the VHE source size. This discovery provides new interest in the potential for high-energy particle acceleration from magnetars, massive stars, and/or stellar clusters.
Place, publisher, year, edition, pages
EDP Sciences, 2018
Keywords
gamma rays: general, stars: magnetars, stars: massive
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Physics, Astroparticle Physics
Identifiers
urn:nbn:se:lnu:diva-76470 (URN)10.1051/0004-6361/201628695 (DOI)000429404700011 ()2-s2.0-85045515161 (Scopus ID)
Available from: 2018-07-10 Created: 2018-07-10 Last updated: 2025-03-27Bibliographically approved
Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. A., Akhperjanian, A. G., Andersson, T., . . . Zywucka, N. (2018). HESS discovery of very high energy gamma-ray emission from PKS 0625-354. Monthly notices of the Royal Astronomical Society, 476(3), 4187-4198
Open this publication in new window or tab >>HESS discovery of very high energy gamma-ray emission from PKS 0625-354
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2018 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 476, no 3, p. 4187-4198Article in journal (Refereed) Published
Abstract [en]

PKS 0625-354 (z = 0.055) was observed with the four High Energy Stereoscopic System (H.E.S.S.) telescopes in 2012 during 5.5 h. The source was detected above an energy threshold of 200 GeV at a significance level of 6.1 sigma. No significant variability is found in these observations. The source is well described with a power-law spectrum with photon index Gamma = 2.84 +/- 0.50(stat) +/- 0.10(syst) and normalization (at E-0 = 1.0 TeV) N-0(E-0)=(0.58 +/- 0.22(stat) +/- 0.12(syst)) x 10(-12) TeV-1 cm(-2) s(-1). Multiwavelength data collected with Fermi-LAT, Swift-XRT, Swift-UVOT, ATOM and WISE are also analysed. Significant variability is observed only in the Fermi-LAT gamma-ray and Swift-XRT X-ray energy bands. Having a good multiwavelength coverage from radio to very high energy, we performed a broad-band modelling from two types of emission scenarios. The results from a one zone lepto-hadronic and a multizone leptonic models are compared and discussed. On the grounds of energetics, our analysis favours a leptonic multizone model. Models associated to the X-ray variability constraint support previous results, suggesting a BL Lac nature of PKS 0625-354 with, however, a large-scale jet structure typical of a radio galaxy.
Place, publisher, year, edition, pages
Oxford University Press, 2018
Keywords
radiation mechanisms: non-thermal, galaxies: active, galaxies: individual: PKS 0625-354, galaxies: jets, gamma-rays: galaxies
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Physics, Astroparticle Physics
Identifiers
urn:nbn:se:lnu:diva-76771 (URN)10.1093/mnras/sty439 (DOI)000430944100087 ()2-s2.0-85052199128 (Scopus ID)
Available from: 2018-07-11 Created: 2018-07-11 Last updated: 2025-03-12Bibliographically approved
Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. A., Akhperjanian, A. G., Andersson, T., . . . Zywucka, N. (2018). HESS observations of RX J1713.7-3946 with improved angular and spectral resolution: Evidence for gamma-ray emission extending beyond the X-ray emitting shell. Astronomy and Astrophysics, 612, Article ID A6.
Open this publication in new window or tab >>HESS observations of RX J1713.7-3946 with improved angular and spectral resolution: Evidence for gamma-ray emission extending beyond the X-ray emitting shell
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2018 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 612, article id A6Article in journal (Refereed) Published
Abstract [en]

Supernova remnants exhibit shock fronts (shells) that can accelerate charged particles up to very high energies. In the past decade, measurements of a handful of shell-type supernova remnants in very high-energy gamma rays have provided unique insights into the acceleration process. Among those objects, RX J1713.7-3946 (also known as G347.3-0.5) has the largest surface brightness, allowing us in the past to perform the most comprehensive study of morphology and spatially resolved spectra of any such very high-energy gamma-ray source. Here we present extensive new H.E.S.S. measurements of RX J1713.7-3946, almost doubling the observation time compared to our previous publication. Combined with new improved analysis tools, the previous sensitivity is more than doubled. The H.E.S.S. angular resolution of 0.048 degrees (0.036 degrees above 2 TeV) is unprecedented in gamma-ray astronomy and probes physical scales of 0.8 (0.6) parsec at the remnant's location. The new H. E. S. S. image of RX J1713.7-3946 allows us to reveal clear morphological di ff erences between X-rays and gamma rays. In particular, for the outer edge of the brightest shell region, we find the first ever indication for particles in the process of leaving the acceleration shock region. By studying the broadband energy spectrum, we furthermore extract properties of the parent particle populations, providing new input to the discussion of the leptonic or hadronic nature of the gamma-ray emission mechanism.
Place, publisher, year, edition, pages
EDP Sciences, 2018
Keywords
acceleration of particles, cosmic rays, ISM: supernova remnants, gamma rays: general, astroparticle physic
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Physics, Astroparticle Physics
Identifiers
urn:nbn:se:lnu:diva-76476 (URN)10.1051/0004-6361/201629790 (DOI)000429404700006 ()2-s2.0-85044161611 (Scopus ID)
Available from: 2018-07-10 Created: 2018-07-10 Last updated: 2025-03-12Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-6511-4330

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