Pos(ICRC2021)918

PoS(ICRC2021)918 International th 12–23 July 2021 July 12–23 37 SICS CONFERENCE SICS CONFERENCE Berlin | Germany Berlin Berlin | Germany Cosmic Ray Conference Ray Cosmic ICRC 2021 THE ASTROPARTICLE PHY ICRC 2021 THEASTROPARTICLE PHY https://pos.sissa.it/ and Luca 4 ONLINE Nathan Grin 0,3 Sean Kelly, 0,2 Jonathan Mackey, ∗ 0,1, 4 [email protected], [email protected] International Cosmic Ray Conference (ICRC 2021) Presenter ∗ th Dublin Institute for Advanced Studies 31 Fitzwilliam Place, Dublin 2, Ireland Institute of Physics and Astronomy, University of14476 Potsdam Potsdam, Germany Centre for AstroParticle Physics and Astrophysics (CAPPA),Dunsink DIAS Lane, Dunsink Dublin Observatory 15, Ireland Dublin City University Collins Ave Ext, Whitehall, Dublin 9, Ireland Argelander-Institut für Astronomie, Universität Bonn, Auf demE-mail: Hügel 71, 53121 Bonn, Germany The remnant of SN 1987Aand is non-thermal the best-studied emission object across ofelaboration its the of kind. particle-acceleration electromagnetic theory. The spectrum richWe poses data-set use a of 2D unique its simulations thermal of testbedthe the for supernova progenitor’s explosion. the wind Various to cones along obtain prominentused hydro-profiles features in for of our the the time-dependent ambient medium acceleration medium around are codeSN then RATPaC 1987A to and model compare the it evolution toWe of observational solve the data. for emission the of transport ofThe cosmic simulation rays code and the relies hydrodynamicalrenders on flow, lateral 1D in transport the profiles unimportant. test-particle but limit. theWe find large that the expansion increase in speed thermal X-ray of emission predatesray the the increase brightness young in by the remnant low-energy gamma- several years.followed by The a increase smooth of increase the atenergies gamma-ray appears the soft brightness during highest the at brightening energies. lower but hardens energies as Theshocked. more is material gamma-ray The in spectrum the X-ray equatorial and at ring gamma-ray gets the brightnesspassed highest remain the almost region constant of once peak-density the in SNR the blast-wave equatorial plane. Copyright owned by the author(s) under the terms of the Creative Commons 4 2 0 1 3 © Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). Robert Brose, Modeling non-thermal emission from SN 1987A Grassitelli 37 July 12th – 23rd, 2021 Online – Berlin, Germany PoS(ICRC2021)918 Myr 25 . 9 ≈ C Robert Brose 202 - is known [13], ◦ years prior to the explosion [22], the Myr. The BSG phase also lasts about . The RSG phase begins at 1 585 − . 20 000 9 ≈ km s C years, which should correspond to the length of 2 4 250 10 = ∼ rot E detection in the epoch between 2016-2018. However, source confusion is a possible and initial rotation velocity f

5 20 M This evolutionary sequence might not be representative of the progenitor of SN 1987A because We first describe our stellar evolution calculations and 2D-simulations of the CSM around the We used Modules for Experiments in Stellar Astrophysics (MESA) [24, 25] to calculate single- There are mainly two mechanisms discussed for the formation of the dense, equatorial ring. The remnant of SN 1987A in the large Magellanic cloud is one of the most well observed Observations from radio [21], infrared [],7 optical [18] to X-ray [12, 17] revealed a rebrightening = 8 " the blue loop begins almostthe 0.4 red-to-blue Myr stellar transition before would the be endwind long of gone of after the the such stars BSG a life. long phase.kinematic time, age driven The of The away nebula by the progenitor the associated circumstellar of fast with rings SN is 1987A, in contrast, exploded as a BSG, and the 0.35 Myr, after which the star re-expands to the RSG branch. time between the critical rotation phase and core collapse. The timing of the red-to-blue transition and ends when the star embarks on a blue loop at progenitor of SN 1987A. Wethe use hydrodynamical the structure CSM around from SN these 1987A.to simulations Afterwards study the to we particle describe construct acceleration the a in 1D “toy” the model model SNR. employed for 2.1 Stellar evolution and 2D hydrodynamic model star evolutionary sequences for rotatingare taken stars from with [3], LMC and metallicity. the particular The evolutionary elemental sequence abundances used is from a star with initial mass other on a spin up to(RSG) critical to rotation a of BSG the progenitor prior star tosimulations during explosion of a [11]. transition the In from ambient this a medium work red with we supergiant a explore one-dimension the code latter for scenario, the combining acceleration 2D of2. CRs. Method One is based on the merger of two massive stars about problem given the spatial resolution of Fermi-LATare at considered this large as distance. sources of Further, very the youngof highest SNRs energetic very-high cosmic-rays (CR). energy So (VHE) far, H.E.S.S.proton gamma-ray found acceleration emission no beyond sign from [10]. TeV-energies SN 1987A that could be associated with astronomical objects. It istelescopes, the and first the supernova only to supernova happenFurther, remnant this the (SNR) close progenitor that to star could - earth be a since observed blue over the its supergiant invention entire (BSG) of lifetime. called Sanduleak -69 of the remnant after the initialthe emission interaction caused by of the the explosion SNR-ejecta hadprogenitor with faded. star. a This Recently, a dense is brightening ring associated at with ofa GeV gamma-ray material claimed energies in was the reported equatorial as well plane [20] around with the Modeling non-thermal emission from SN 1987A 1. Intoduction enabling a connection between theby stellar the evolution star and and the the evolution circumstellar of medium the (CSM) SNR for shaped the first time. PoS(ICRC2021)918 ¤ s. " pc (1) 10 2 . , and 0 ◦ 10 2 ≈ ± [19] with , from the ◦ Robert Brose PION Gas temperature region to develop (using the “Dutch” ii 0 ¤ " , we linearly increased 5 . 0 lower over a period of Figure 1: (a) and densitythe equatorial region (b) and upper showing half-plane of a 2D axisymmet- ric simulation of wind-wind in- teraction as a star evolves from RSG to BSG,critical spinning rotation up in the to The process. CSM is shown 10 000 yr af- ter the criticalDot-dashed rotation lines phase. are the dashed line 35 equatorial plane. × > 10 crit E /  by a factor of 5 at critical rotation; in rot 5 E . ¤ 0 " 5 ≡ . − 0 Ω Ω 4 + 3 1  0 ¤ " = 1 ¤ " is the enhanced mass-loss rate with respect to the MESA rate, 1 ¤ " We performed 2D radiation-magnetohydrodynamic (MHD) simulations using We modified the mass-loss history of the calculation in two ways: reducing the mass-loss rate the above-mentioned stellar evolution modela providing circumstellar an nebula inner similar boundary tophases condition, that of to of near-critical generate SN rotation 1987A. followsfrom [16, Focusing the19]. of central the1 Figure star, wind surroundedshows towards a by the dense a equator equatorial photoevaporation at flow ring expanding from the ring. This flow where mass-loss[5, scheme 32]). Thisthe prescription MESA calculation, increases the total massneeded lost is for thought the to contracting be star regulated toloss by remain the at at angular critical momentum sub-critical rotation loss rotation. are1987A Nevertheless, poorly is the understood evidence details that and significant of the mass mass can observedmass be is mass lost. in in The the the ad-hoc equatorial modification equatorial ring ensures ring to that agree sufficient of with SN observations. after critical rotation, and increasing itreduced around the the mass-loss rate critical linearly rotation from phase. the standard After rate critical to a rotation rate we is extremely sensitive to many ofthat the this tunable calculation embarked parameters on in a stellar blueis loop evolution not 0.35 codes, a Myr strong and (and prediction so not of0.025 the any Myr) stellara fact before evolution blue code. the loop end just There of before are the its calculations end life wherein of the its determining star life goes whether [15]. on such Nevertheless, a this red-to-blue evolutionarya sequence transition nebula is for instructive similar a to rotating that star seen could, in in SN987A. principle, produce Modeling non-thermal emission from SN 1987A This was to reduce thearound ram the pressure of equatorial the ring wind, (seein thereby below the allowing and a weak [4]). larger wind H [27]. measured Such During low for the rates the phase have of apparent some near-critical Galactic rotation, observational when twin support of the SN 1987A progenitor, SBW1 according to the following presciption: PoS(ICRC2021)918 (2) . ◦ 15 region and ± ii Robert Brose vs. ◦ 30 Density structure of in the H ≈ ± 3 − &, + Figure 2: the two cones used for the mod- eling of the soft X-ray emission and the acceleration of CRs.  g/cm #? 22 − E 3 ∇ì 10 ode (RATPaC) to calculate the particle × C ) − ¤ 3 ? # ( rallel  Pa , as well as the outer ring and an inner cone with a high-density equatorial m ◦ m? 4 ◦ 1 . 0 20 ) − ± ± E# ransport vs. T − ì ◦ 2 # ∇ ≈ ±  . We set the densities - region between the BSG wind and the equatatorial ring [4]. The ◦ ∇( 1 ii = cceleration ± A mC m# in the dense ring - in order to reproduce the observed soft X-ray lightcurve of adiation 3 R − g/cm 20 − Based on the results from the previous section, we constructed a “toy”-model2) (Figure that The X-ray emission is calculated from the gas density and temperature using the approximations We use the We solve the kinetic equation for the transport of CRs in the form 10 × features an outer cone with an extension of produces a photoionized H structure is similar to the model proposedhas by a Dewey et somewhat al. larger extension, [6], with the difference that the inner ring 2.2 Toy model ring with a cone-width of Modeling non-thermal emission from SN 1987A 2 SN 1987A (see also3). Figure equatorial ring. In this The density “toy”-model distribution we derived from consideredwill the a MHD-simulation decrease suggests constant after that the density reaching density in the theX-ray peak, flux dense which in is recent also years [8]. more in line with the evolution ofof the Hnatyk thermal & Petruk [14].assuming local We thermal note equilibrium is that not this strictlyheating valid calculation in and of the ionization case the shortly of after continuum SN the 1987A thermal supernovastar. given explosion X-ray the by However, emission additional a the detailed radiation fields modeling of of thederived the progenitor emission X-ray is emission a is crude beyond estimate the to scope tailor of the density-profiles this used paper for and the the CR-acceleration code. 2.3 Particle acceleration acceleration and subsequent thermal and non-thermalcan emission. be A found here: detailed description [2, of28–30]. the code 2.3.1 Cosmic-rays PoS(ICRC2021)918 c ì E A (6) (4) (3) (5) is the & Robert Brose the momentum ì Ed up to the radius  = c d = ì < 1 − % W + is the minimum momentum for the total energy of the ideal gas , 2 inj ej ì E  2 ? ' : d erg [31]. The initial temperature is is the spatial diffusion coefficient, ej . ≤ 51 ' ,  ej c A 10 , ≤ × , ª ® ® ¬ . c the plasma velocity, 5 2 for SN 1987A [23]. The velocity of the ejecta . 0 0 0 ì E 3 A SN b 1 b ) 8 4 © ­ ­ « ,A , A > ' = = = c = ) = 5 4 − A ) √ = ej  ( ) A c  ( ª ® ® ¬ A A = G and the field in the downstream has a constant value the unit tensor, and  ej ` , A < A ì E ì  [  E CSM c c )ì % d d d % ì E           125 + + d = ì  )

. 0 . We assume that the magnetic field is dynamically unimportant due to its low strength " 3 = the thermal pressure of the gas, / 14 is the differential number density of cosmic rays, 5 % G. SN = = ` # ) ej W We assume the thermal leakage injection model [1], where The standard gasdynamical equations We solve the transport equation for protons in 1D using the RATPaC code as described in We apply Bohm-like diffusion in the interior of the remnant assuming a simple magnetic-field The exponent for the ejecta profile is set to We initialize the ejecta profile by a plateau in density with the value " 410 where of source term. which a thermal particle canefficiency cross for the the compression shock ratio and of enter 4 is the determined acceleration as process and the injection are solved, where of 2.3.2 Hydrodynamic evolution [2, 28–30] taking intoproton account spectra only a at forward differentremnant. shock epochs and In are ignoring this then study the used werays reverse will do to shock. not not dynamically calculate consider effect Resulting acceleration the the SNR of Pion-decay evolution. electrons emission and from also assume the geometry that with cosmic- a constantupstream is field assumed in to be/amplified the to upstream and downstream respectively. The field in the Modeling non-thermal emission from SN 1987A where is the plasma velocity, is defined as and the remnant not beingspherical symmetry. in the radiative phase yet [26]. The equations are solved in 1D for a density, with followed by a power-law distribution up to the ejecta-radius PoS(ICRC2021)918 Robert Brose by the interaction 1 Left hand side: Ther- − km s GeV to produce gamma-rays Figure 3: mal X-ray flux ofbased SN on 1987A thethe emission two from cones,their surface weighted area, by to compared Chandra observationsRight hand side: [8]. Photon Fluxes in theH.E.S.S. Fermi-LAT [10] energy [20] ranges. and years between the accelerated 1000 8 100 ≈ between 2002 and 2017. There is 100 ≈ region only and the inner cone also containing ii 6 pc grid-size for the hydro simulations. 2 in 2012, when the interaction with the dense equatorial ring 10 ≈ K everywhere and the initial pressure is calculated using the equation of state. We used linearly distributed grid-points and 4 10 000 The “toy”-model that we constructed based on our 2D MHD simulations reasonably well 3 Figure shows the gamma-ray photon fluxes in the Fermi-LAT high-energy (1-100GeV) and We further assume in Eq.5 that the SNR is expanding into the CSM created by the progenitor , with the dense material, greatly increasing the acceleration time of CRs. detectable by Fermi-LAT. The shock-speed is reduced to the order of reproduces the observed soft X-rayThe light first curve is3). (Figure that our However,SNR-shock here simulations starts are can not two interacting things account with for toadditional the the note. clumping dense suppressed hard needs equatorial X-ray to ring. fluxenough be as temperature soon assumed The as [6]. in main the order reason These1987A to is, clumps by generate that could providing a therefore further additional plasma-componentequatorial enhance with target the ring a material gamma-ray low- to for luminosity p-p-interactions. staysimulations of and dense. SN supported Secondly, by the we However, flattening assumed of a the the reduction X-ray light-curve3.1 of of SN the 1987A Gamma-ray [8]. density flux is observed in the MHD- H.E.S.S. very-high energy (1-10TeV) rangesevident compared that to the high-energy the flux predictions increases from by a our factor model. of It is 130 the material in the densethen equatorial the ring. emission from The both cones simulationassociated is is with combined run the accounting independently opening for the for angles. different both fractional cones surface and areas 3. Results star. We read in the density, velocitycones and pressure considered, distribution the from outer our “toy”-model. cone featuring There are the two H set to a sharp increase by atranslates factor into of an increased gamma-ray flux.brightening in There X-rays is and a the delay brightening of energy CRs in responsible high-energy for gamma-rays. the emission The in the reasonfrom Fermi-LAT is domain the are that shock advectively transported the with away low- the flow.dense material. They are Thus not CRs able need to to return be easily freshly when accelerated the beyond shock interacts with the Modeling non-thermal emission from SN 1987A PoS(ICRC2021)918 ii Robert Brose Comparison of the Figure 4: simulated gamma-ray spectra between 2008 andFermi-LAT 2017 [20] and and H.E.S.S. observations [10]. between 2002 and 2017 on account 10 ≈ 7 at these energies. That is considerably softer than predicted 6 . 2 region provide a soft spectrum at energies beyond a few hundreds ≈ ii B The mechanisms explained in the previous section are also evident in the comparison of the The transition from the freshly accelerated low-energy CRs from the dense equatorial ring and This increased acceleration time is also responsible for the lack of a strong increase of the very- It has to be noted that the injection efficiency that we assumed for our models is the value gamma-ray spectra between 2008 and 2017 shown ininjected4. Figure after the It interaction is with evident the that dense none equatorial offor ring the have H.E.S.S. been particles accelerated by to 2017. energies relevant However, the shock propagating in the outer cone, associated with the H the high-energy CRs from the H of the expansion of the remnant.back to Further, the CRs shock with and probe energies the beyondequatorial higher a density ring. TeV there, can once more the easily SNR diffuse started to interact with the dense 3.2 Gamma-ray spectra region, is increasing inenergies size is taking and place. still Thus, moving the increaseby at in this brightness a intermediate at very-high high density energies region. is velocity, still so solely powered that acceleration to post-TeV of GeV with a spectral index of high energy gamma-ray luminosity. Theof reduced freshly acceleration injected efficiency CRs prevents the tothe acceleration relevant H.E.S.S.-domain energies is (see expected to also increase4). Figure by a factor However, the of gamma-ray flux in that is roughly consistent withinjection injection fraction fractions is observed a inmodel, free historical parameter is remnants. in associated acceleration Formally, with the order models the to and, multiple get in accelerated of as case the CRsmaterial of by thermal that the the is momentum shock. thermal-leakage needed that However, we inenhance particles like the the to equatorial need gamma-ray note luminosity ring to that from in the that have order region. additional,& in to clumpy A Aharonian explain similar [9] the model has for hard been RX X-rayray proposed emission J1713.7-3946. by emission will Gabici from also However, the there shock-crushed ismaterial dense a at clouds lack corresponding in of temperatures case intermediate-temperature hasthe of X- been equatorial RX ring detected. J1713.7-3946. of SN Further, For 1987A theclumping, provide SN observed which already 1987A, experimental might optical evidence need knots for to a in be significant amount taken of into account additionally when modeling the gamma-ray by standard DSA. Modeling non-thermal emission from SN 1987A PoS(ICRC2021)918 3 ≈ region. ii Robert Brose region and (ii) ii & Lamers, H. J. G. L.2001, M. A&A, 369, 574 in American InstitutePhysics of Conference Se- ries, Vol. 937, Supernova 1987A: 20 YearsSupernovae After: and Gamma- Ray Bursters, ed. S. Imm- ler, K. Weiler, & R.Cray, 25–32 Mc- Dwarkadas, V.Pohl, V., M. & 552, 2013, A102 A&A, Dwarkadas, V.Pohl, V., M. & troparticle Physics, 2012,300 35, As- Pohl, M.618, 2018, A155 A&A, France, K., &R. McCray, 2017, MNRAS,2333 468, Beshley, V. 2016,RAS, MN- 456, 2343 [32] Vink, J. S., de Koter, A., [31] Utrobin, V. P. 2007, [30] Telezhinsky, I., [29] Telezhinsky, I., [28] Sushch, I., Brose, R., & [27] Smith, N., Groh, J. 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[15] Langer, N. 1991, A&A, [16] Langer, N., García- [17] Larsson, J., Fransson, C., to perform 2D MHD simulations based on a red-to-blue transition of the rotating PION We find a good agreement betweenemission. our derived density-distribution and observed soft X-ray Our model predicts a significant2017 brightening with at a high-energy strong gamma-rays increase between aroundmarginal 2002 2012. detection and The of predicted SN fluxes 1987A are in consistent Fermi-LAT with data. the recent We predict an increase ofbetween 2002 the and very-high 2017 powered energy by gamma-ray the acceleration luminosity in by the a intermediate-density H factor of We used S. A., Park, S., et al. 2016, ApJ, 829, 40 Bouchet, P., et al.ApJ, 722, 2010, 425 V. V., Haberl, F., Sturm, R., & Canizares,2012, ApJ, C. 752, 103 R. jzen, H., & van der Hucht, K. A. 1988, A&AS,259 72, Dwarkadas, V. V. 1995, ApJL, 452, L45 Cantiello, M., et al. 2011, A&A, 530, A115 Pohl, M.,A&A, et 627, A166 al. 2019, Vannoni, G. 2005, MN- RAS, 361, 907 • • • [8] Frank, K. A., Zhekov, [7] Dwek, E., Arendt, R. G., [6] Dewey, D., Dwarkadas, [5] de Jager, C., Nieuwenhui- [4] Chevalier, R. A. & [3] Brott, I., de Mink, S. E., [2] Brose, R., Sushch, I., [1] Blasi, P., Gabici, S., & References the particle acceleration and gamma-ray emission from SN 1987A using RATPaC. Modeling non-thermal emission from SN 1987A emission. 4. Conclusions progenitor star of SN 1987A tothese derive MHD a simulations, model with for the two CSM. conesan We containing intermediate constructed (i) a density an toy-model H intermediate based density on H