PoS(ICRC2021)672 International ∗ th 12–23 July 2021 July 12–23 37 SICS CONFERENCE SICS CONFERENCE 0, Berlin | Germany Berlin Berlin | Germany Cosmic Ray Conference Ray Cosmic -ray W ICRC 2021 THE ASTROPARTICLE PHY ICRC 2021 THEASTROPARTICLE PHY https://pos.sissa.it/ -ray emission eV) CR. Ultra -ray emission, W W 17 10 -LAT source 4FGL & ONLINE  Fermi erg. 52 10 and Vadym Voitsekhovskyi ∼ 0 rot  eV triplet – by the hadronic and leptonic 20 10 ) eV and extragalactic ( 18 -ray emission from the vicinity of the magnetar  > W 10 . Valery Zhdanov 0  eV) are believed to be of extragalactic origin, but some 18 10  > Roman Hnatyk, 0 [email protected], , [email protected] International Cosmic Ray Conference (ICRC 2021) Presenter ∗ th Taras Shevchenko National University of Kyiv, AstronomicalObservatorna Observatory st. 3, Kyiv, Ukraine E-mail: [email protected], [email protected] One of the unsolved problemsacceleration mechanism(s) in of cosmic Galactic ray ( (CR) physics is the determination of sources and high energy CR (UHECR, contribution from transient Galacticcreated sources is by possible. newborn millisecond So,and magnetars, magnetar even and wind potential magnetar nebulae sources giant (MWNe), in of flares UHECR. magnetars’ are Promising neighbourhoods PeVatron signature candidates shouldemission of be effective due nonthermal acceleration to high-energy processes ppCompton and scattering collisions very of low high-energy with energy background a photons(leptonic by scenario). subsequent ultrarelativistic electrons pion and positrons decayIn (hadronic this scenario) work and we inverse explain the HE and VHE SGR 1900+14 – potential Galactic sourceemission of of cosmic raysMWN. accelerated To this end in we have a carried out magnetar-relatedspatially a coincident Supernova simulation of with remnant the the observed (SNR) HE magnetarJ1908.6+0915e, and and/or SGR VHE the 1900+14. extended The H.E.S.S. extended HAWC TeV source source 3HWC J1907+085 were candidate considered. HOTS We show that J1907+091 thefrom observed and the the magnetar point-like SGR 1900+14connected super-luminous outskirts Supernova can (Hypernova) remnant be and/or explainedmillisecond a magnetar by MWN with a a created (still large by initial undetected) newborn rotational energy magnetar- Copyright owned by the author(s) under the terms of the Creative Commons 0 © Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). Bohdan Hnatyk, High-energy and very high-energy gamma-ray emission from the magnetar SGR 1900+14 outskirts 37 July 12th – 23rd, 2021 Online – Berlin, Germany PoS(ICRC2021)672 , , ∼ ◦ 69 . 77 . ◦ 0 0 ) with and an 6 . = 1 = ◦ − 0 1 G – exhibit , 1 , ◦ 15 erg rotational erg s s. Huge initial 88 02 . . 10 Θ = 3 52 4 ◦ − − i,-3 − 43 10 42 erg can reveal itself % 10 14 = 2 2 15 = ; ∼ − i,-3 10  ; Vadym Voitsekhovskyi i % 49 ∼ % 52 10 , radius of -ray bursts with luminosities 10 W ≈ ) is the TeV point-like source × 43 . kpc, giant flare in 1998 [15]) is 2 ◦ 75 . sd,i 0 5 ◦ ≈ . ! 0 erg. Approximately one GF with s [3,6,7, 17]. = rot 12 ≈ 46 1  2 -ray band SGR 1900+14 is overlapping i,-3 = , W % 10 3 2 12 − 15 − . -ray flares (soft gamma-repeaters, SGRs), ◦  W 3 44 43 10 10 s) hard X-ray – soft = 2 × 1 ∼ ; . 2 0 ≈ kyr, distance ∼ ) with a somewhat low (TS = 75.5) peak on an extended 9 . sd,i -LAT) and VHE (H.E.S.S., HAWC) gamma-ray observa- 0 44 ! . / ◦ = 0 rot 2 Fermi g =  [1] (Fig. 1b). In the VHE 1 = , f sd,i 35 . C ◦ 42 and released energies = 1 -ray activity: persistent/transient quiescent super-luminous X-ray emission, − ; ) with cross-check TS = 43 [9]. In the 3HWC HAWC Observatory Gamma-Ray W eV CR triplet (Fig. 1a) is a promising candidate on MWN/Hypernova-related 17 erg is expected to occur every 6 (200) years [4]. Until now, three GFs have been -ray band SGR 1900+14 is overlapped by extended source 4FGL J1908.6+0915e 20 . erg s W ◦ ) 0 10 46 47 -LAT Fourth Source Catalogue ( of magnetars is expected to have millisecond initial periods 2 10 10 − ( Θ =  > − 44 10 Fermi 44 − 10 Both magnetar GFs and MWNe of newborn millisecond magnetars are potential sources of In this work we analyse HE ( Untill now magnetar SGR 1900+14 in massive star cluster Cl1900+14 ( In the HE Magnetars – young neutron stars with extremely high magnetic fields Only a few percent of newborn pulsars are magnetars, and only a very small fraction, 3 10 −  > 3HWC J1907+085 ( background spot (Fig. 1b). Catalogue [2] the nearest to SGR 1900+14 (a separation of radius of UHECR [5,8]. For example,close magnetar to SGR1900+14 with detected GF and position in the sky magnetar of millisecond initial periodemission with from corresponding their observational outskirts signatures [10–13]. in nonthermal tional data of the magnetar SGRa 1900+14 Hypernova-like environment explosion (Fig. of1b) a and explain progenitor them massive in star the with model contribution of of 2. SGR 1900+14 and its neighbourhood: observations energy of newborn fast rotatingthe magnetar MWN SGR formation. 1900+14 to the Hypernova energy reserve and to overall significance only 4.58 with the H.E.S.S. extended source candidate (hotspot) HOTS J1907+091 ( of the detected only in X-ray- soft gamma -raydetected band yet and in no the signatures radio of - an X-ray adjacent bands. SNR or MWN were initial spin-down timescale period P=5.2 s, characteristic age VHE gamma-ray emission from magnetar SGR1900+14 1. Introduction persistent X-ray – as a magnetar wind nebula (MWN)ejecta and/or by a magnetic Hypernova via dipole additional radiation energization with of spin-down a luminosity Supernova together with short (milliseconds-seconds) bursts and longerX-ray (weeks-months) outbursts pulsars, (anomalous AXPs), repeated hard X-ray – soft including rare giant flares (GFs) - the∼ short ( rotational kinetic energy of a newborn millisecond magnetar detected in our Galaxy and LMCoutside (including the from Local magnetar Group SGR1900+14) [18]. and three GFs from the 10 PoS(ICRC2021)672 eV 2 kyr 20 ∼ 10  > Vadym Voitsekhovskyi kyr estimate from new (b) 4 . -LAT extended source 4FGL 2 ≈ erg in the form of spherically 2 4A<8 g 52 10 [19]) with the 4 BCE "po star" [20] ≈ 1 erg. − rot erg of ejecta’s energy can be provided by 52  s s 52 10 11 10 ∼ − 3 ∼ 10 :8= ×  3 . 3 error box) are presented. Two SNRs in the field (the orange rings) = f ¤ % - ray band [12]. W -ray sources can be signatures of magnetar- connected SNR/MWN. W s and ) -ray sources in the magnetar region. The 3 W ( (a) 22669 . 5 = Magnetar SGR 1900+14 neighbourhood. Left (a): backwards trajectories of % SGR 1900+14-related HNR/MWN should manifest themselves as PeVatrons with nonthermal Moreover, another scenario is possible when considerable part of newborn MWN plasma In both cases the high pressure of MWN plasma inside SN ejecta results in R-T instability and All these HE and VHE emission from the radio to TeV suggests a Hypernova type of a magnetar-related Supernovaacceleration with favourable [14]. conditions for UHECR Necessarynewborn for millisecond Hypernova magnetar SGR1900+14 with age of SNR2). (Fig. destroys and protrudes the ejecta shell andahead evolves till the present fragmented to debrises a large of size initialup (tens ejecta. of ISM parsecs) plasma Depending MWN may on be ISM formed. density a new shell from swept fragmentation of ejecta at distancesemission of 2-4 massive pc star cluster from - SN SGR1900+14 cradle outburst. - supports Morphology the Hypernova of model infrared and (IR) dust symmetric or jet-like collimated magnetar windfollowing that Hypernova additionally remnant energizates (HNR) Supernova up ejecta to and triplet in the magnetar region.Right The (b): background image: HE courtesy and NASA/JPL-Caltech/R. Hurt, VHE SSC/Caltech. data for Figure 1: J1908.6+0915e (the light bluethe circle), H.E.S.S. the extended source three HOTS extragalactic J1907+091J1907+085 point-like (the (the 4FGL brown green circle) sources bullet and with (the the theare black HAWC 1 not point-like bullets), physically source connected 3HWC with the region considered. Moreover, association of SGR1900+14 (with an improved age VHE gamma-ray emission from magnetar SGR1900+14 PoS(ICRC2021)672 (1) ) and 1 − km s pc) shell-like [16]. 40 of ISM. − 5000 02 3 . − 0 30 ≈ ≈ cm ∼ Vadym Voitsekhovskyi 2 / ' 10 HNR 1 C ) / p ≈ , < )  kyr) HNR is at the ST stage / HNR = e 2 ' cut,i < 4 ( .  ≈ -LAT and H.E.S.S. spectral energy e.TheTeV. Hypernova model explains 0 / ) extended ( . 3 3  = − erg evolves inside the low-density wind ep = HNR (− C

Fermi 0 cm erg) total energy of the proton component 52 as a differential power-law spectrum with a .  HNR 1

exp 52 10 10 − + i at s W M ∼ 10 ∼ ) − 2 4 0 ) − ≈ sh 4  0,i 10 = ( HNR cm  ×   / 2 13 3 (#' .  − ( 0 , ∼ 10 0,i = m) (courtesy NASA/JPL/Caltech/S. Wachter (Caltech-SSC)). In G). At present ( ) # × ` ` 0 3 = .  3 ( 4 ) i . =  X ( ) i w pc, the shock velocity erg and an enhanced number density #  and 50 TeV 24 , 2 3 1 . , where electron-to-proton ratio 10 − ≈ ) 0 m), and red (24 × `  ± ( cm 5  > p 3 2 . ( HNR − # ≈ 2 '  -ray emission is generated mainly by the hadronic mechanism (pp-collisions with ep 10 = W

W (#' ∼ = , -LAT and H.E.S.S. sources (the HAWC source flux is similar to that of the H.E.S.S. ) w The background image is a Spitzer IR map of SGR 1900+14 environment with a colour coding:  = m), green (16 05 ( . ` e 0 # In order to estimate the necessary Hypernova remnant and cosmic ray parameters to explain Observed In our Hypernova model the HNR with remnant case ≈ 4A<8 ? observed SED with the Hypernova-type ( photon index the halo of the swept up stellar cluster gas of source) we have carried outdistributions the (SEDs) NAIMA-fitting in [21] the of HNRTeV integral model flux 3, (Fig. 1). Table Herewith we present the H.E.S.S. 1-10 the subsequent neutral pion decay) in the dense ( bubble ( (the shell radius shock-accelerated CR protons (i=p) and electrons (i=e) obey exponential cut-off power-law spectra 3. Gamma-ray emission of the SGR 1900+14 neighbourhood in the Hypernova our model the observed IRejecta dust debris emission and of the massive broken shell stellar is cluster created dominates by by the a anisotropic spherical giant flare shell of of the dusty magnetar. with Figure 2: blue (8 VHE gamma-ray emission from magnetar SGR1900+14 , PoS(ICRC2021)672 ≈ (2) 4 , G) in the ` 0.19 1.06 0.17 ± ± ± 0.44)e34 2 ± .  -LAT and H.E.S.S. Vadym Voitsekhovskyi erg, that is, corresponds Fermi 50 2,e 0.190.00080.11 1.81 9.99 - br,e 10 W ± ± ± 0.51)e38 (8.81 −  × ± ) erg ahead ejecta’s debris inside 5 ≥ 0,e 52  ≈ / -ray emission by the inverse Compton ,  10 ) W  br,e ( ≈ ' ) cut,e , 1,e rot W   41.7 0.0096 / − 0.010.0003 1.91 0.070.06 - 1.65 - - 2.58 ± , ± ± ± ± 0.12)e40 (4.41  2,e ,  <  . W ± ( br,e 1,e (− ) W  5 − 0,e ) ≥ exp MWN  0,e  / ×   / br,e for   9.5 396.7 ( ( 2 0.35 - - - 0.03 1.49 0.01 0.19 0.0002 - - - erg) of energy transfered to MWN from newborn millisecond ± ± ± ± ± 0.05)e37 (1.90 0,e 0,e > 52 ± # #         10 2,e W = ∼ )  and ( e 0.66 9.81 0.1 0.78 0.01 2.41 br,e # ± ± - - 3.04 ± 0.04)e35 (1.42 PL ECPL ECBPL ECPL #1 ECPL #2  erg. Taking into account radiative and adiabatic energy losses, large value of ± ≤ 2.55 0.02 (fixed) 0.0041 50  10 HNR and MWN NAIMA-fitted models of SED from SGR 1900+14 neighbourhood × for 5 2 ≈ < ] 11.42 3 − -LAT and H.E.S.S. sources we have carried out NAIMA-fitting of A>C 1,e Table 1: [TeV] - 185.2 [GeV](fixed) 1e6 1e6 1e6 1e6 1e6 [GeV](fixed) 1 1 1 1 1 [TeV] - - 0.0047 W [1/ eV] (1.18 [TeV] 3.93 In MWN case electrons and positrons generate observed In order to estimate the necessary MWN and leptonic cosmic ray parameters to explain the To summarise, in both cases of HNR/MWN the observational data can be explained only when Powerful relativistic magnetar wind can destroy and penetrate the Hypernova ejecta and after- Parameter HNR: PL and ECPL spectra (i=p) MWN: ECBPL(i=e) MWN:Two electron population spectra (i=e) , [erg] 5.03e50 5.12e50 - - - [erg] 1.04e49 2.16e48 3.60e50 5.20e50 6.08e49 [cm confirms the large amount ( p e 0,i ep min max 0,i br,i cut,i 1,i 2,i H 4 05 #     

W W = , , . 4A<8 (IC) scattering of the background CMB, IR and star light (SL) photons (leptonic mechanism)4). (Fig. SEDs in the MWNvariants model4, of (Fig 1). leptonic Table cosmic MWNelectron ray model spectrum ECPL explains (exponential populations observed cut-off etc.) SEDs0 broken in power-law different (ECBPL), only two- with unusually large total energy of CR leptons to the millisecond period ofthe a radio- and newborn X-ray magnetar non-detection1). (Table correspondsmagnetar to Moreover, neighbourhood. a in low HNR value of and magnetic MWN field cases ( the total energy of cosmic rays ( protons or electrons) is magnetar. with wards support an expansion of MWN with VHE gamma-ray emission from magnetar SGR1900+14 4. Gamma-ray emission of the SGR 1900+14 neighbourhood in the MWN case the low-density wind bubble tillshock present. (TS) or Electrons in and magnetic positrons reconnectionthe are processes result accelerated and at of the a present the relativistic termination time-dependentexponential leptons cut-off acceleration in broken MWN and power-law spectrum are cooling/escaping/advection is processes. expected in this Typical case , PoS(ICRC2021)672 Vadym Voitsekhovskyi (b) -LAT 4FGL J1908.6+0915e (in red), H.E.S.S. Fermi 6 ◦ 40 = I ). Observations of ep

(a) Modelled SED of the magnetar SGR 1900+14 neighbourhood in the MWN model. (a) The case Modelled SED of the magnetar SGR 1900+14 neighbourhood in the HNR model. NAIMA-fitted Figure 4: of MWN termination shock/reconnection acceleratedspectrum. leptons with an The exponential total cut-off gamma-rayIR broken flux power-law and is SL a background sum photons.two of electron the The populations contributions rest with from of exponential ICgamma-ray fluxes the cut-off scattering as sums data power-law of of spectra. is leptons the contributions on thephotons from For CMB, are same IC both presented. scattering as populations of NAIMA-fitted in leptons parameters Only on3. Fig. are CMB, the given IR total in and (b)1. SL Table Same background as in (a) but for HOTS J1907+091 (in blue) andflux HAWC is 3HWC a J1907+085 sum (in of green)of hadronic are electrons (pp presented. on collisions CMB, with IR The the and totalof SL subsequent gamma-ray the background neutral CTA photons) pion South contributions. decay) array The and for blue a leptonic line zenith (IC represents angle scattering the sensitivity Figure 3: parameters are given in1 Table (thepower-law case spectra of with HNR shock free accelerated proton and electron exponential cut-off VHE gamma-ray emission from magnetar SGR1900+14 PoS(ICRC2021)672 erg 52 10 ∼ -ray band the erg. The new A>C W  52 . 10 ∼ Vadym Voitsekhovskyi ",# A>C   2 kyr and agree with Hypernova ∼ ) extended shell-like halo of swept up -ray emission by the IC scattering of 3 W − cm 10 ∼ -ray emission from the SGR 1900+14 region can 7 W Bℎ = erg. 50 -ray emission from the magnetar SGR 1900+14 neighbour- (2019) 1426 (2019) 2215 10 -ray emission is generated mainly by the pp collisions with W W × (2020) 33 487 5 487 ∼ 247 (2000) L123 cr,e , ≈ 533 cr,p ) of massive stellar cluster-SGR 1900+14 cradle. In the TeV ,

M 4 10 × 3 ∼ If the powerful relativistic magnetar wind effectively penetrates the Hypernova ejecta, the We have explained the observed In the HNR model, most of the magnetar rotational energy is transformed to the Hypernova Observational fluxes of the HE and VHE The Milky Way Galaxy image: courtesy NASA/JPL-Caltech/R. Hurt, SSC/Caltech. The [1] S. Abdollahi et al., ApJS [2] A. Albert et al. arXiv:2007.08582 [3] C. R. Angus et al., MNRAS [4] P. Beniamini et al., MNRAS [5] P. Blasi et al., ApJ resulting energy-dominated MWN with energy loss corrected reserve contribution of the ICelectrons scattering can of be important. background CMB, IR and SL photons by shock accelerated expands inside the low-density windthe bubble TS till or present. in magnetic Electrons reconnection and positrons, processes, accelerated generate at shell, now at an adiabatic stage ofspread evolution. over Shock the accelerated HNR nuclei shock and and electrons are the diffusively Spitzer IR image of(Caltech-SSC). the SGR 1900+14 environment: courtesy NASA/JPL/Caltech/S. Wachter References VHE gamma-ray emission from magnetar SGR1900+14 5. Summary hood in a model of magnetar-connected HNRfrom and MWN a created fast-rotating by an newborn energy supply magnetarX-ray to data with a of SN initial SGR ejecta rotational 1900+14 observations energy type support of age a estimate visually detected (ancientoutburst. Chinese Additional records confirmation on of 4 Hypernova BC type of Aprsignatures SN 24) in follows from distant the an (12.5 recent absence kpc) radio- of Supernova to SNR/MWN and X-ray low observations density due of to wind high bubble initial interior, velocity in of Hypernova which shell shell is still expanding. subsequent neutral pion decay ingas the ( dense ( background CMB, IR and SL photons. be explained in both- HNRmodels and is MWN the models1, requirement (Table 3,4). Figs. ofcosmic the ray The energy considerably main higher challenge than of the these ordinary SNR/PWN value of total 6. Acknowledgements PoS(ICRC2021)672 Vadym Voitsekhovskyi (2020) 129 36 (2016) 1 (2018) 167 (2017) 224 8 32 34 472 (2014) 6 (1992) L9 (2011) 119 (2018) A1 (2007) 1541 212 392 49 612 380 (2021) 211 (2019) 90 589 (2002) L43 (2019) 34 71 569 (1993) 91 878 270 [9] H. E. S. S. Collaboration, A&A [8] K. Fang et al., ApJ [6] N. Bucciantini et al., MNRAS, [7] R. C. Duncan, Thompson C., ApJ [19] T. Tamba et al., PASJ [20] Z. Wang et al., ApJ [21] V. Zabalza, arXiv:1509.03319 [17] T. Sukhbold, Thompson T. A., MNRAS [18] D. Svinkin et al., Nature [16] M. Pohl, A&A [15] S. A. Olausen, V. M. Kaspi, ApJS [10] R. Gnatyk, Kinemat. Phys. Celest. Bodies VHE gamma-ray emission from magnetar SGR1900+14 [11] R. Gnatyk, Kinemat. Phys. Celest. Bodies [12] B. Hnatyk, R. Hnatyk, V. Zhdanov, V. Voitsekhovskyi, arXiv:2009.06081 [13] R. Hnatyk, V. Voitsekhovskyi, Kinemat. Phys. Celest. Bodies [14] K. Kotera, A. V. Olinto, ARA&A