Hanke, F.

Janka, H.T.

Müller, B.

Raffelt, G.G.

Tamborra, I.

English

In the delayed explosion scenario of a core-collapse supernova, the accretion phase shows pronounced convective over-turns and a low-multipole hydrodynamic instability, the so-called standing accretion shock instability (SASI). Neutrino signal variations from the first full-scale three-dimensional core-collapse supernova simulations with sophisticated neutrino transport are presented as well as their detection perspectives in IceCube and Hyper-Kamiokande

International Migration, Integration and Social Cohesion online publications

UvA-DARE is a service provided by the library of the University of Amsterdam (https://dare.uva.nl)UvA-DARE (Digital Academic Repository)Fast-time Variations of Supernova Neutrino Fluxes and Detection PerspectivesTamborra, I.; Hanke, F.; Müller, B.; Janka, H.T.; Raffelt, G.G.DOI10.1016/j.phpro.2014.12.076Publication date2015Document VersionFinal published versionPublished inPhysics ProcediaLicenseCC BY-NC-NDLink to publicationCitation for published version (APA):Tamborra, I., Hanke, F., Müller, B., Janka, H. T., & Raffelt, G. G. (2015). Fast-time Variationsof Supernova Neutrino Fluxes and Detection Perspectives. Physics Procedia, 61, 359-365.https://doi.org/10.1016/j.phpro.2014.12.076General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s)and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an opencontent license (like Creative Commons).Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, pleaselet the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the materialinaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letterto: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. Youwill be contacted as soon as possible.Download date:09 Mar 2023 Physics Procedia  61 ( 2015 )  359 – 365 Available online at www.sciencedirect.com1875-3892 © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).Selection and peer review is the responsibility of the Conference lead organizers, Frank Avignone, University of South Carolina, and Wick Haxton, University of California, Berkeley, and Lawrence Berkeley Laboratorydoi: 10.1016/j.phpro.2014.12.076 ScienceDirectFast-time variations of supernova neutrino fluxes and detectionperspectivesI. Tamborraa,1,∗, F. Hankeb, B. Müllerb,2, H.-T. Jankab, G.G. RaffeltaaMax-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, 80805 München, GermanybMax-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, GermanyAbstractIn the delayed explosion scenario of a core-collapse supernova, the accretion phase shows pronounced convective over-turns and a low-multipole hydrodynamic instability, the so-called standing accretion shock instability (SASI). Neutrinosignal variations from the first full-scale three-dimensional core-collapse supernova simulations with sophisticated neu-trino transport are presented as well as their detection perspectives in IceCube and Hyper-Kamiokande.c© 2014 Published by Elsevier Ltd.Keywords: neutrinos, supernova, hydrodynamical instabilities1. IntroductionBethe and Wilson’s delayed neutrino-driven explosion mechanism [1] remains the standard core-collapsesupernova (SN) paradigm [2]. At core bounce a shock wave forms, it looses all its energy dissociating atomswithin the iron shell and is then revived by neutrino heating after O(102) ms. During the accretion phase,large-scale convective overturn develops in the neutrino-heated postshock layer [3] and the standing accre-tion shock instability (SASI) can arise, involving sloshing motions of the shock front [4, 5] as well as spiralmodes [6, 7, 8, 9, 10]. The next galactic SN may reveal these effects in gravitational waves [11, 12] as wellas in neutrinos [13, 14].Up to now, SN investigations of convection and SASI were based on axisymmetric simulations wheresloshing motions are constrained to the symmetry axis. Several recent 3D models found SASI sloshingmotions with considerably reduced amplitudes or no clear SASI signature at all. Convection was concludedto dominate post-shock turbulence and SASI to be a minor feature of SN dynamics. However, SASI devel-opment may depend on progenitor properties and the exact behavior of the stalled shock (which requiresreliable neutrino transport) and self-consistent, 2D simulations with sophisticated neutrino transport suggest∗Corresponding authorEmail addresses: i.tamborra@uva.nl (I. Tamborra ), fhanke@mpa-garching.mpg.de (F. Hanke),bernhard.mueller@monash.edu (B. Müller), thj@mpa-garching.mpg.de (H.-T. Janka), raffelt@mpp.mpg.de (G.G. Raffelt)1Present address: GRAPPA Institute, University of Amsterdam, Science Park 904, 1090 GL Amsterdam, The Netherlands.2Present address: Monash Center for Astrophysics, School of Mathematical Sciences, Building 28, Monash University, Victoria3800, Australia© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).Selection and peer review is the responsibility of the Conference lead organizers, Frank Avignone, University of South Carolina, and Wick Haxton, University of California, Berkeley, and Lawrence Berkeley Laboratory360   I. Tamborra et al. /  Physics Procedia  61 ( 2015 )  359 – 365 that SASI remains possible for small shock stagnation radii [15]. The first 3D simulation with detailedneutrino transport (a 27 M SN progenitor) shows indeed violent SASI activity [10].The SASI activity strongly modulates the neutrino emission. The detection of such fast time variationsof the neutrino signal will offer a unique chance to probe stellar core collapse [13, 14]. IceCube [16] isamong the most promising facilities for this task, detecting a large number of Cherenkov photons triggeredby neutrinos. Moreover, Super-Kamiokande (Super-K) [17], or the next-generation Hyper-Kamiokande(Hyper-K) [18] will monitor the neutrino signal without background and provide event-by-event energyinformation.We here discuss the detection opportunities for a SASI-modulated SN neutrino signal based on theworld-wide first 3D simulations with detailed neutrino transport of three SN progenitors with 27 M, 20 M,and 11.2 M.2. Numerical supernova modelsWe use solar metallicity progenitors for which the evolution until the onset of iron-core collapse hasbeen reported in [19] for the 11.2 and 27 M stars and in [20] for the 20 M star. The 3D modeling usesthe Prometheus-Vertex hydrodynamics code, including state-of-the-art neutrino interaction rates [21] andrelativistic gravity and redshift corrections [22, 23].The adopted description assumes the neutrino momentum distribution to be axisymmetric around theradial direction, implying that the neutrino fluxes are radial. The detectable energy-dependent neutrinoemission from the hemisphere facing an observer is therefore determined with a post-processing procedurethat includes projection and limb-darkening effects [24].3. Detection perspectives: 27 M supernova modelIn the largest operating detectors, IceCube and Super-K, neutrinos are mainly detected by inverse betadecay, ν̄e + p → n + e+. We represent the neutrino energy spectra in the form of Gamma distributions[25, 26] and estimate the neutrino signal as described in [27], assuming an overall background rate ofRbkgd = 1.48 × 103 ms−1 (comparable to the signal rate for a SN at 10 kpc).IceCube will register O(106) events above background for a SN at 10 kpc, to be compared with around104 events for Super-K (fiducial mass 32 kton), i.e., IceCube has superior statistics. While the future Hyper-K will have a fiducial mass of 740 kton, providing a background-free signal of roughly 1/3 the IceCube rate.Moreover Hyper-K will provide event-by-event energy information (which we do not use here).To get a first impression of the neutrino signal modulation we consider the 27 M model [10]. Figure 1shows the expected rate in IceCube and Hyper-K. This model shows clear SASI activity at 120–260 ms. At∼220 ms a SASI spiral mode sets in and remains confined to an almost stable plane not aligned with thepolar grid of the simulation. The first SASI episode ends abruptly with the accretion of the Si/SiO interface,followed by large-scale convection with much smaller and less periodic signal modulations. After about410 ms, SASI activity begins again until the end of our simulation. In the top panel, we select an observerlocated in the SASI plane in a favorable direction and show the expected IceCube signal. While the secondpanel of Fig. 1 is for a direction orthogonal to the plane of the first SASI episode (i.e., the signal modulationis smaller than before).Neutrinos change their flavor as they propagate from the SN core to the detector. Other than theMikheev-Smirnov-Wolfenstein (MSW) neutrino flavor conversions, neutrino-neutrino interactions occurwhile neutrinos propagate through the SN envelope. However, since we still miss a detailed picture ofthe impact of neutrino-neutrino interactions on the SN neutrino signal due to the non-linear nature of theproblem, we choose to show the two extreme scenarios in Fig. 1. One case assumes the signal caused byunoscillated ν̄e (i.e., ignoring flavor conversions), while the other case assumes complete flavor conversionso that the signal is caused by ν̄x (with ν̄x a combination of ν̄μ and ν̄τ). Note as both cases reveal large signalmodulations with a clear periodicity and, therefore, assuming that the observed signal will be anything inbetween these two extreme cases, SASI modulations will be clearly detectable. I. Tamborra et al. /  Physics Procedia  61 ( 2015 )  359 – 365 361Fig. 1. Detection rate for the 27 M SN progenitor, upper panels for IceCube, bottom one for Hyper-K. The observer direction ischosen for strong signal modulation, except for the second panel (minimal modulation). Upper two panels: IceCube rate at 10 kpc forν̄e (no flavor conversion) and for ν̄x (complete flavor conversion). The lower two panels include a random shot-noise realization, 5 msbins, for the indicated SN distances. For IceCube also the background fluctuations without a SN signal are shown.362   I. Tamborra et al. /  Physics Procedia  61 ( 2015 )  359 – 365 Fig. 2. IceCube detection rate for our 27 M SN progenitor on a 4π map for t = 217, 225, 230 ms.In the third panel of Fig. 1 we show the IceCube ν̄e signal in 5 ms bins, including a random shot noiserealization since the main limitation to observing signal modulations are random fluctuations in the detectedneutrino time sequence. The SASI modulation of the neutrino signal will be clearly visible for a SN up to20 kpc (roughly the edge of the expected galactic SN distance distribution [28]).In the bottom panel of Fig. 1, we show the expected signal in Hyper-K. For SN distances beyond some10 kpc, the future Hyper-K detector would be superior to IceCube. In fact in spite of its smaller signalrate (about 1/3 of IceCube), its lack of background implies a better signal-to-noise ratio because of reducedshot noise for those distances where IceCube is dominated by background fluctuations. To exploit the fullHyper-K potential, its event-by-event energy determination should be used as well.The observed signal is strictly dependent on the location of the observer and, for fixed location of theobserver, the detected rate oscillates with time. We show in Fig. 2 three snapshots of the detection rate at theobserver for t = 217, 225, 230 ms. Note as, due to the modulation of the emitted neutrino signal, locationswith the highest detection rate became afterwords the ones with lowest rate and viceversa.As a static visualization we show in Fig. 3 the relative amplitude of the IceCube detection rate duringthe first SASI episode. To define this amplitude we first note that the signal rate, averaged over all directionsis not modulated. In a given direction we define the relative time-dependent rate and consider its root meansquare deviation for the first SASI episode ([t1, t2] = [120, 250]ms),σ ≡⎛⎜⎜⎜⎜⎜⎝∫ t2t1dt[R − 〈R〉〈R〉]2⎞⎟⎟⎟⎟⎟⎠1/2. (1)The time integrated analysis still reveals a dominant sloshing direction, which is responsible for two signal“hot spots” in two opposite directions, surrounded by directions with much smaller modulations. We can I. Tamborra et al. /  Physics Procedia  61 ( 2015 )  359 – 365 363Fig. 3. Relative amplitude of the ν̄e rate modulation (see Eq. 1) on a sky-plot of observer directions during the first SASI episode(120–250 ms) of the 27 M model.conclude that almost the 50% of the locations an observer will be able to detect SASI.4. Detection perspectives: Other progenitorsFig. 4. IceCube rate for optimal observing directions for the 11.2 and 20 M models at 10 kpc, as in the top panel of Fig. 1.Figure 4 shows the IceCube rate for the other two analyzed progenitors (11.2 and 20 M) in optimalobserving directions. For the heavier case, a strong SASI phase appears for t ∈ [140, 300] ms. For thisprogenitor, the signal large-amplitude modulations are more pronounced than for the 27 M progenitor, onlyone SASI phase occurs. Moreover, the SASI plane is different from the one of the 27 M SN progenitorand this is clearly shown in Fig. 5 where, analogously to Fig. 3, we plot the relative amplitude of the ν̄e ratemodulation (as in Eq. 1) on a sky-plot of observer directions during the SASI episode.The 11.2 M model exhibits neutrino-driven convection without any clear signs of large-amplitude co-herent SASI motions (see Fig. 4). The detection rate for this progenitor is smaller than for the other twoprogenitors because of a lower luminosity.Following Ref. [13], we illustrate the signal for the three progenitors in terms of its Fourier powerspectrum for t ∈ [100, 300] ms (where SASI develops for our progenitors). With the adopted signal durationof τ = 200 ms, the spacing of the discrete Fourier frequencies is δ f = 1/τ = 5 Hz. Where we use theIceCube dark current as a natural baseline and adopt its power to normalize the signal power spectrum.Figure 6 shows the power spectrum of the IceCube event rate for our three SN models thus normalized.A clear peak exists at ∼80 Hz for the 27 and 20 M progenitors where strong SASI appears. Note that forboth the two heavier progenitors the SASI frequencies are similar because of similar neutron star radii (thesame equation of state is used) and mean shock radii in the first 250 ms after bounce.364   I. Tamborra et al. /  Physics Procedia  61 ( 2015 )  359 – 365 Fig. 5. Relative amplitude of the ν̄e rate modulation (see Eq. 1) on a sky-plot of observer directions during the SASI episode (140–300 ms) of the 20 M model.Fig. 6. Power spectrum of the IceCube event rate on the interval 100–300 ms for our three progenitors, assuming the ν̄e signal from adistance of 10 kpc. Normalization is to the frequency-independent power of shot noise caused by the IceCube background of 1.48 ×103 ms−1.5. ConclusionsThe first 3D SN simulations with sophisticated neutrino transport are available for 11, 20 and 27 M SNprogenitors. They show pronounced spiral SASI activity for the two more massive progenitors, while thelighter one is dominated by large-scale convective overturn activity.Such detectable instabilities appear to be dependend on the progenitor properties. If detected by Ice-Cube and the future Hyper-K, the neutrino signal of the next galactic SN will offer a unique opportunity todiagnose different types of hydrodynamical instabilities and to test the supernova explosion mechanism.6. AcknowledgmentsThe results presented here were obtained in Refs. [27, 29]. The authors are grateful to the TAUP 2013organizers for kind hospitality.References[1] H. A. Bethe and J. R. Wilson, Astrophys. J. 295, 14 (1985).[2] H.-T. Janka, Ann. Rev. Nucl. Part. Sci. 62, 407 (2012).[3] H. A. Bethe, Rev. Mod. Phys. 62, 801 (1990).[4] J. M. Blondin, A. Mezzacappa and C. DeMarino, Astrophys. J. 584, 971 (2003).[5] L. Scheck, H.-T. Janka, T. Foglizzo and K. Kifonidis, Astron. Astrophys. 477, 931 (2008).[6] J. M. Blondin and A. Mezzacappa, Nature (London) 445, 58 (2007).[7] W. Iwakami et al., Astrophys. J. 700, 232 (2009).[8] R. Fernández, Astrophys. J. 725, 1563 (2010).[9] T. Foglizzo, F. Masset, J. Guilet and G. Durand, Phys. Rev. Lett. 108, 051103 (2012). I. Tamborra et al. /  Physics Procedia  61 ( 2015 )  359 – 365 365[10] F. Hanke et al., Astrophys. J. 770, 66 (2013).[11] J. W. Murphy, C. D. Ott and A. Burrows, Astrophys. J. 707, 1173 (2009).[12] B. Müller, H.-T. Janka and A. Marek, Astrophys. J. 766, 43 (2013).[13] T. Lund et al., Phys. Rev. D 82, 063007 (2010).[14] T. Lund et al., Phys. Rev. D 86, 105031 (2012).[15] B. Müller, H.-T. Janka and A. Heger, Astrophys. J. 761, 72 (2012).[16] R. Abbasi et al. (IceCube Collaboration), Astron. Astrophys. 535, A109 (2011).[17] K. Abe et al. (Super-Kamiokande Collaboration), Phys. Rev. D 83, 052010 (2011).[18] K. Abe et al., arXiv:1109.3262.[19] S. E. Woosley, A. Heger and T. A. Weaver, Rev. Mod. Physics 74, 1015 (2002).[20] S. E. Woosley and A. Heger, Phys. Rep. 442, 269 (2007).[21] R. Buras, M. Rampp, H.-T. Janka and K. Kifonidis, Astron. Astrophys. 447, 1049 (2006).[22] M. Rampp and H.-T. Janka, Astron. Astrophys. 396, 361 (2002).[23] A. Marek et al., Astron. Astrophys. 445, 273 (2006).[24] E. Müller, H.-T. Janka and A. Wongwathanarat, Astron. Astrophys. 537, 63 (2012).[25] M. T. Keil, G. G. Raffelt and H.-T. Janka, Astrophys. J. 590, 971 (2003).[26] I. Tamborra et al., Phys. Rev. D 86, 125031 (2012).[27] I. Tamborra, F. Hanke, B. Müeller, H. -T. Janka and G. Raffelt, Phys. Rev. Lett. 111 (2013) 121104.[28] S. M. Adams et al., Astrophys. J. 778 (2013) 164.[29] I. Tamborra et al., in preparation.

Fast-time Variations of Supernova Neutrino Fluxes and Detection Perspectives

https://pure.uva.nl/ws/files/710715/173909_Fast_time_Variations_of_Supernova_Neutrino_Fluxes.pdf

Fast-time Variations of Supernova Neutrino Fluxes and Detection Perspectives

Abstract

Similar works

Full text

Available Versions

International Migration, Integration and Social Cohesion online publications