sign in sign up
<<
Home , Axion, Sterile neutrino

PoS(ICRC2021)556 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 2 ONLINE Kenny C. Y. Ng 0 Fabian Zimmer, 1 Ebo Peerbooms, ∗ 0,1,3 0,1, [email protected] International Cosmic Ray Conference (ICRC 2021) Presenter ∗ th The of dark remains anSterile open question and and could -like be in are the wellinto form motivated of , warm warm dark which dark candidates, are matter. and consequently can detectable decay Both by particles -ray could telescopes explain with the keV observed dark unidentifiedobserved matter 3.5 an . keV excess line at and, a interestingly, few XENON1T keV thatemission can coming originate from the from Galactic axion-like halo, particles. andto We test study the identify the sensitivity a diffuse of sterile all-sky X-ray surveythe eROSITA or mixing axion-like angle . of the By sterileeROSITA, we Monte neutrinos will Carlo and be method, coupling able we to strength set set ofprobe stringent bounds the the constraints, on axion-like best-fit and particles. of in the particular, With wesensitivity. unidentified will Moreover, 3.5 eROSITA be is keV able able line, to to where confirm firmly an weexcess for axion-like reach an particle an excess origin greater order of than the of 3 XENON1T magnitude keV. better GRAPPA Institute, University of Amsterdam, 1098 XHInstitute Amsterdam, for The Theoretical Netherlands Physics, University of Amsterdam,Department 1098 of XH Physics, Amsterdam, The The Netherlands Chinese University ofKavli Hong Institute for Kong, the Shatin, Physics Hong and KongKashiwa, Mathematics China Chiba of 277-8583, the Japan (Kavli IPMU, WPI)E-mail: University of Tokyo, Copyright owned by the author(s) under the terms of the Creative Commons 2 0 1 3 © Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). Ariane Dekker, 37 July 12th – 23rd, 2021 Online – Berlin, Germany Probing sterile neutrinos and axion-like particlesGalactic from halo the with eROSITA Shin’ichiro Ando PoS(ICRC2021)556 (1) per ) ≈ \ 2 3 ( / 2 sin decay Ariane Dekker 3# is given as follows, , and decay into two photons, Ω 6 3 , energy spectrum keV and mixing angle B a 7 < ∼ , B a < decay 3 3# B a 2 B a Γ c< 4 the sterile neutrino mass, which photon is observable as = B a Φ < 3 , sterile neutrino mass 3 B a Γ , with keV was detected through a stacked X-ray spectrum analysis of 73 2 / 5 . B a 3 . The X-ray flux from a region < ∼  = W  [2]. Follow-up studies both confirmed the emission line [3–5], as well as provide ) 10 − 10 ) × 2 Sterile neutrinos are well motivated candidates, and can solve some issues in the An emission line at As another interesting possibility, decaying ALP could explain the observed excess of recoil In this work, we estimate the sensitivity of all-sky eROSITA’s X-ray survey to observe decaying X-ray photons from sterile neutrino decay inside the Galactic halo produce a flux which depends − 2 . 0 ( for which we adopt a deltadark function matter for density the profile energy of spectrum the Milky per Way decay. halo, integrated The over D-factor the describes line the of sight, and we consider . They have right-handed , in contraryhave to left-handed the chirality. standard model This neutrinos feature which gives ato natural have explanation mass, for and the moreover, standard it model can neutrinos mixing solve the with matter- asymmetry active of neutrinos, the universe.photon sterile with Through energy neutrinos can decay into a standard model neutrino and a Probing sterile neutrinos and axion-like particles with eROSITA 1. Introduction a monochromatic line signal by X-rayGoldstone telescopes. Axion-like that particles can (ALP) emergeALPs are when pseudo-Nambu- can a couple continuous global to symmetry standard is model spontaneously particles broken. through coupling, producing likewise a monochromatic line signal in X-rays. galaxy clusters [1], suggesting experimentalbe evidence interpreted for a as dark decaying matter sterile decay neutrino signal with which mass could events over known backgrounds3 at keV. Since the the XENON1T ALP coupling experiment,observations to [10] which standard in model is order particles to most is explainis already this prominent suppressed. excess, tightly We a at constrained follow an model by 2- -free is X-ray symmetry requiredwithout model, any in in anomalous which which coupling the the to ALP photon photons, is and coupling coupledcorrections. where to photons are only induced through threshold sterile neutrino and ALPaverage signals. exposure of eROSITA 2.5 will ks, observe anda the moreover, valuable due full probe to sky for its dark during excellentlargest matter angular four dark and decay years matter energy with with induced resolution, narrow an X-rayhalo. it X-ray flux, is line By we emissions. simulating study all-sky X-ray the Insterile count order diffuse neutrino maps, and to emission we ALP make obtain signal coming a under the from a sensitivityus background-only the projection to hypothesis. probe for Galactic We eROSITA for find to a that a eROSITA much allows large parameter space for both sterile2. neutrino and ALP X-ray dark sky matter. map 2.1 Sterile neutrino signal on the sterile neutrino decay rate strong constraints on decaying dark matter due to non-detections [6–9]. decay, and the D-factor, PoS(ICRC2021)556 4 − (4) (5) (2) (3) keV pho- 10 1 . × − ◦ 24 6 . 5 . . 0 20 0 3 ± < | Ariane Dekker 1 44 | . 8 in the northern and , and is given by the 2 \ − . , 1 5 ,  − 2 s  B 2 a arcmin 14 − − <  1 1 keV − 04  10 6 ·  GeV ) 5 \  0 7 14 2 5 − 7 (  2 10 , and mixing angle 10 B × , 0 a sin 5  < <  2 keV 1 0WW 0WW − 3  s  c6 3 U 2 29 0 − GeV and 0.0026 photons s < ≡ 10 7 keV 2 57 0  5 − − × 29 10 and with a normalization at 1 keV of − 38 . × 1 10 5 03 arcmin . . = × is the decay constant, where we adopt the following relation with 1 3 0 ) − 5 0 [10]. 5 ' ± ,\ ' B 75 a WW . 42 [18]. Besides these two isotropic background components, we consider . WW 0 < [17]. Moreover, eROSITA’s detector background consist of high en- → 1 2 ( , 0 → ≈ 1 B − 0 Γ a − Γ Γ 0WW sr 92 . 6 Γ = 1 1 − arcmin − 1 3 − keV / s 8 1 1 . − − = s is the ALP mass and 04 the coupling between the ALP and . The energy spectrum of the ALP decay is 0 2 6 − 0WW < 04 e.ThekeV. X-ray bubbles are observed by eROSITA with an average count rate in the or 6  The cosmic X-ray background contributes to the diffuse emission and we consider a power-law In order to explain the XENON1T excess by ALP, we adopt an anomaly-free symmetry model, Moreover, we include the extragalactic component for completeness, however, we find that the ALP can couple to photons and produce 2 photons with the following decay rate [15] 3 . 2 0WW 6 counts keV energy band of 0.0038 photons s southern bubbles respectively [19], and weits consider morphology, an downloaded uniform from template.https://fermi.gsfc.nasa.gov/ssc/data/access/ ofexclude Finally, the the in Fermi extended order emission bubbles to from for the Galactic plane, we remove all pixels with the X-ray bubbles, which flux is subdominant with∼ respect to detector eROSITA’s background below ton cm ergy particles and show a flat spectral energy distribution with a normalization of with photon index with where photons are induced through threshold corrections. The decay rate is given by [16] with also described by a deltaflux function, and we which use allows the for obtained a X-ray bounds direct on the comparison mixing with angle and the convert sterile to the neutrino coupling strength 2.3 Backgrounds extragalactic flux is more than an orderenergy of bins magnitude that smaller than we the adopt Galactic in flux this within paper. the small 2.2 Axion-like particle signal Probing sterile neutrinos and axion-like particles with eROSITA both the spherically-symmetric Navarro-Frenk-White (NFW) [11]The profile decay and rate a depends cored on profile thefollowing [12]. decay sterile rate neutrino [13, mass, 14], where the photon coupling PoS(ICRC2021)556 (6) . We 11 − 10 keV line and × 7 5 Ariane Dekker . 3 = ) is related to the full \ keV line by Ref. [1]  2 ( eV for eROSITA [20], 5 f . 2 3 , sin 138 ) Γ = ( 8 , where `  − ! 4 f 8 8 = = ) FWHM Γ . ( 8 71 ` . with 2 8 E = . An anomaly-free ALP model is adopted, Ö f with bin size 13 = TS − 2 keV and mixing angle ] / 4 ) 10 1 2 ln 2 < Γ . ( √ 7 8 ∼ / ks, eROSITA will be sensitive to the ` = 2 | 8 5 04 B . = = a 6 [ 2 < % = 8 ) Ö FWHM = ) Γ runs over the energy bins as well as the spatial pixels. The likelihood to 8 L( , assuming background only through Monte Carlo simulations for each dark 8 = are the expected counts in each bin under the signal hypothesis with decaying dark ) keV. Γ as a function of the decay rate for a specific mass is given by the likelihood functions: ( 1 8 –3 keV and electron coupling 8 . 2 ` = 7 The sensitivity of eROSITA to the photon coupling is shown in Fig. 2a, where the best-fit for Moreover, we test if eROSITA will be able to probe the parameter space relevant for the We consider in total 13 energy bins around The sensitivity of eROSITA on the mixing angle as a function of the sterile neutrino mass = = B 0 a < < for which the expected sensitivityobservations are is in presented grey, in and The Fig. indeed, expected2b . we sensitivity probe of a The Athena taken parameter excludedthe from red space region Ref. dashed not based [30] dotted yet line. show on constrained comparable The X-ray dark sensitivity, [8, black grey as solid23–29]. box line shown highlights shows as roughly the the XENON1T best-fit limitmay parameter at not space 90% from CL reach Ref. [31], the [32]. and best-fit the Future for eROSITA data the XENON1T excess, however, if the best-fit alters towards higher matter mass point, where obtain the 3.5 keV line is indicatedunassociated by X-ray the line black [8], star. in(see Even which though the [8, recent23–29]), current work eROSITA found X-ray willby limits no be current evidence are able X-ray for to shown limits. an probe as a the region grey of shaded the area parameter spaceobserved not yet XENON1T excluded excess, which has been observed to be most prominent at ALP mass of for each sterile neutrino and500 ALP mock mass, data and sets, range their mass between 2 and 20 keV. We generate can even constrain the mixing angles up to nearly two orders of magnitude below the best-fit at is presented in figure1.the The Monte two Carlo green runs, bands show whereasThe the the orange 68% dashed green dotted and solid line 95% line illustratesand containment represents the we regions the median find from of median little the with dependence Montedue the on Carlo NFW to runs the profile. with dark density a profiles. matter coredX-ray underproduction profile, observations The [8, [21, lower23–29]. grey22], area Moreover, while is the the excluded best-fit by upper of theory the grey unidentified area is excluded by current Probing sterile neutrinos and axion-like particles with eROSITA 3. Analysis width at half maximum through where 4. Results is indicated as a black star,find with that mass with an exposure time of matter and background component. We determineestimation with the the best-fit test model statistic under (TS), alevel and maximum (CL), obtain which likelihood upper corresponds limits to on a the test decay rates statistic of at 95% confidence PoS(ICRC2021)556 10 9 XENON1T . The 8 (b) RG cooling 7 ] V Ariane Dekker e k 6 [

20.0

a WD cooling WD m 5 NFW Cored 17.5 4 ALP-electron coupling (b) Excluded by X-ray 3 This work ATHENA 15.0 and ALP-electron coupling (a) 2 ] 1 0 1 V

Excluded by X-ray 0 0 12.5

0 1 1

e

1

e a

] V e G [ 0 1

k g

1 3 [ 1

s 10.0 m 5 20.0 7.5 17.5 DM underproduction 15.0 5.0 Excluded by X-ray ] V represents the XENON1T limit at 90% C.L. [31] and the dark grey box 12.5 e k sensitivities from the Monte Carlo runs and the blue solid line the median. [ 2.5 (b)

a 1 2 3 4 0 f 1 1 1 1 1 2 10.0 m

0 0 0 0 0

1 1 1 1 1

n i s ) 2

( 7.5 2 ALP-photon coupling (a) 5.0 Sensitivity to the mixing angle as a function of the sterile neutrino mass for the cored (dashed Current and future limits on the ALP-photon coupling 2.5 0 8 9 7 2 1 1 1 0 0 0 0

1 1 1 1

a ] V e G [ g 1 Figure 2: blue bands show the 1 and Figure 1: orange) and NFW (green) profiles,the showing median the (solid 68% line) and from the 95% Monte containment Carlo regions runs of with the an sensitivities NFW profile. and ALP mass, still inside the XENON1TALP excess origin region could of be interest confirmed. withtaken Interestingly, energies comparison from between with 1–7 Ref. the keV, an [30] expected sensitivityregion shows of for similar the Athena sensitivity. white dwarf cooling Thevalues anomaly, whereas yellow for the shaded the yellow dotted red area line giant illustrates illustratesobserved the excesses branch the in preferred cooling in preferred of globular stellar objects, clusters whichregions could [32–34]. be are explained close by These ALP, to and stellar their the preferred XENON1T cooling excess. anomalies are The black solid line inhighlights roughly figure the best-fit parameter space from Ref. [32]. Probing sterile neutrinos and axion-like particles with eROSITA PoS(ICRC2021)556 , (2014). A suzaku Ariane Dekker 113 A deep search , 2014. ) and ALP-electron Sterile neutrino Dark 0WW 6 , 2021. (2015) 161301. 115 (2014) 103506. Unidentified line in x-ray spectra Checking the dark matter origin ]. 90 (2020) 1465–1467. Letters , 367 1807.07938 e,whichkeV, might be well tested with eROSITA. Phys. Rev. Lett. 3 Phys. Rev. D , 6 , ∼ Science Decaying dark matter search with nustar deep sky Constraints on 3.55 kev line emission from stacked , 0 The dark matter interpretation of the 3.5-kev line is < (2016). (2019) 1[ 94 104 (2014) 13. 789 ), as well as on the ALP-photon coupling ( \ Physical Review D , ). Prog. Part. Nucl. Phys. , 04 6 inconsistent with blank-sky observations The Astrophysical Journal Matter of the andromeda galaxy and perseus galaxy cluster for decaying dark matter with xmm-newton blank-sky observations Detection of an unidentified emission line in the stacked x-ray spectrum of galaxy clusters observations observations of dwarf spheroidal galaxies of a 3.53 kev line with the center search for dark matter emission lines in the x-ray brightest galaxy clusters The all-sky eROSITA survey allows us to search for decaying sterile neutrino and axionlike- In the case of sterile neutrinos, we will be able to probe aMoreover, we value will for be the able mixing to angle probe up the to ALP couplings to photons and with values [3] A. Boyarsky, O. Ruchayskiy, D. Iakubovskyi and J. Franse, [8] J.W. Foster, M. Kongsore, C. Dessert, Y. Park, N.L. Rodd, K. Cranmer et al., [9] C. Dessert, N.L. Rodd and B.R. Safdi, [2] A. Boyarsky, M. Drewes, T. Lasserre, S. Mertens and O. Ruchayskiy, [6] O. Urban, N. Werner, S.W. Allen, A. Simionescu, J.S. Kaastra and L.E. Strigari, [1] E. Bulbul, M. Markevitch, A. Foster, R.K. Smith, M. Loewenstein and S.W. Randall, [4] A. Boyarsky, J. Franse, D. Iakubovskyi and O. Ruchayskiy, [5] A. Neronov, D. Malyshev and D. Eckert, [7] D. Malyshev, A. Neronov and D. Eckert, particle (ALP) signal from the Galacticwell halo. as expected We sky generate maps mock with data counts sets fromyears decaying with sterile of background neutrinos only, observations. in as the Galactic Following halo, a withangle four likelihood of analysis, sterile we obtain neutrinos stringent ( bounds on the mixing Probing sterile neutrinos and axion-like particles with eROSITA 5. Conclusion coupling ( References nearly two orders of magnitude below theorder best-fit of value magnitude of below the the unidentified existing 3.5 upper keV limits line claimed [1] in and the one literaturethat [8, are23–29]. not yet excluded byof X-ray sterile observations, to neutrinos. the same Weanomaly-free investigate degree symmetry both of model a improvement for as general the in model ALP-to-electronthe the coupling for case that the XENON1T has ALP-to-photon excess been coupling of proposed and to electronexplained an by explain an recoil ALP events origin for [31]. an excess at The XENON1T excess could possibly be PoS(ICRC2021)556 ]. , , The Probing the (2016) 2573 Detection of Phys. Rev. D Ariane Dekker erosita science , 459 ]. (2014) 178–182. 734 . Improved Limits on Sterile ]. ]. (2021) A1. (2020) 227–231. 647 588 , 2012. astro-ph/0204147 2008.02283 Physics Letters B , , 1801.08127 X-ray background measurements with Nature ]. Anomaly-free flavor models for , (2005). ]. A Universal density profile from hierarchical 71 7 (2002) 93[ Dark mat- astro-ph/9611107 The 7 keV axion dark matter and the X-ray line (2018)[ 89 389 1402.6965 102 1311.0282 ]. asymmetry and primordial nucleosynthesis in the era Astronomy & New experimental approaches in the search for axion-like , (1997) 493[ Closing in on resonantly produced sterile neutrino dark matter , 2021. Monthly Notices of the Royal Astronomical Society , (2014) 25[ 490 Physical Review D , (2017). Sterile neutrino dark matter bounds from galaxies of the Local Group 733 95 1504.04027 Astron. Astrophys. , Neutrinos in astrophysics and : Theoretical advanced study (2014) 025017[ 89 Astrophys. J. Prog. Part. Nucl. Phys. , , Phys. Lett. B , (2015) 043503[ https://academic.oup.com/mnras/article-pdf/459/3/2573/8105757/stw713.pdf particles clustering [ Milky Way’s for the 3.5 keV Line ter cores all the way down institute (tasi) 2020 lectures signal nambu–goldstone bosons and the x-ray line signal book: Mapping the structure of the energetic universe xmm-newton epic of precision cosmology erosita x-ray telescope on srg large-scale x-ray bubbles in the milky way halo Physical Review D Phys. Rev. D Neutrino Dark Matter using Full-Sky Fermi Gamma-Ray92 Burst Monitor Data S. Garrison-Kimmel, Probing sterile neutrinos and axion-like particles with eROSITA [10] I.G. Irastorza and J. Redondo, [13] D. Sicilian, N. Cappelluti, E. Bulbul, F. Civano, M. Moscetti and C.S. Reynolds, [11] J.F. Navarro, C.S. Frenk and S.D.M. White, [12] J.I. Read, O. Agertz and M.L.M. Collins, [14] K.N. Abazajian, [16] K. Nakayama, F. Takahashi and T.T. Yanagida, [15] T. Higaki, K.S. Jeong and F. Takahashi, [17] D. Lumb, R. Warwick, M. Page and A. De Luca, [20] A. Merloni, P. Predehl, W. Becker, H. Böhringer, T. Boller, H. Brunner et al., [21] P.D. Serpico and G.G. Raffelt, [22] J.F. Cherry and S. Horiuchi, [24] K.C.Y. Ng, S. Horiuchi, J.M. Gaskins, M. Smith and R. Preece, [18] P. Predehl, R. Andritschke, V. Arefiev, V. Babyshkin, O. Batanov, W. Becker et al., [19] P. Predehl, R.A. Sunyaev, W. Becker, H. Brunner, R. Burenin, A. Bykov et al., [23] S. Horiuchi, P.J. Humphrey, J. Onorbe, K.N. Abazajian, M. Kaplinghat and PoS(ICRC2021)556 , Phys. Rev. D New , (2017) 123002 Ariane Dekker Nustar tests of (2020) 161801 Excess electronic Almost closing 95 (2017) 1–28. 125 (2014) 069 , Revisiting the axion 10 711-712 Phys. Rev. D , M31 Observations JCAP , Phys. Rev. Lett. , #D() ' (2020). Physics Reports , ]. 102 8 XENON1T Excess from Anomaly-Free Axionlike Dark Searching for Sterile Neutrino with X-ray Intensity (2016). ]. 93 1911.09120 Toward a full test of themsmsterile neutrino dark matter model Physical Review D (2020). , (2020) 001[ 101 1901.01262 Sterile neutrinos in cosmology 03 ]. ]. Physical Review D ]. , JCAP , MSM sterile neutrino dark matter window with NuSTAR (2013). a (2019) 083005[ 2006.10035 1406.7712 1609.00667 [ recoil events in xenon1t Matter and Its Implications for Stellar Cooling Anomaly bounds from the Galactic white dwarf[ luminosity function Neutrino and axion bounds from the111 globular cluster m5 (ngc 5904) 99 sterile-neutrino dark matter: New galactic bulgePhysical observations Review and D combined impact Mapping with athena Constraints on Sterile Neutrino Dark Matter from the [ [33] M.M. Miller Bertolami, B.E. Melendez, L.G. Althaus and J. Isern, [34] N. Viaux, M. Catelan, P.B. Stetson, G.G. Raffelt, J. Redondo, A.A.R. Valcarce et al., [32] F. Takahashi, M. Yamada and W. Yin, [31] E. Aprile, J. Aalbers, F. Agostini, M. Alfonsi, L. Althueser, F. Amaro et al., [30] A. Neronov and D. Malyshev, [27] K.N. Abazajian, [28] A. Caputo, M. Regis and M. Taoso, [29] B.M. Roach, K.C. Ng, K. Perez, J.F. Beacom, S. Horiuchi, R. Krivonos et al., Probing sterile neutrinos and axion-like particles with eROSITA [25] K. Perez, K.C.Y. Ng, J.F. Beacom, C. Hersh, S. Horiuchi and R. Krivonos, [26] K.C.Y. Ng, B.M. Roach, K. Perez, J.F. Beacom, S. Horiuchi, R. Krivonos et al.,