Detection of Gravitational Waves and Neutrinos from Astronomical Events

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1 Detection of Gravitational Waves and Neutrinos from Astronomical Events Jia-Shu Lu IHEP,CAS April 18, 216 JUNO Neutrino Astronomy and Astrophysics Seminar 1 / 24

2 Outline Sources of both GW and neutrinos. Detection of GW and neutrino signals. Summary and physics potential. 2 / 24

3 Sources of both GW and neutrinos Core-collapse supernovae. Merging binary stars. Binary neutron stars. Black hole-neutron star system. 3 / 24

4 Core-collapse supernovae Total energy released: 1 53 erg. Neutrino takes away 99% of total energy. Neutrinos from SN1987A have been observed. GW is believed to be emitted during SN explosion. Many mechanisms are related with GW emission. 4 / 24

5 Neutrino emission of SNe Three phases of SN explosion have characteristic neutrino emission. νe burst: neutronization releases large amount of ν e in 1 ms. Accretion phase: capture of e ± on the PNS gives rise to the emission of ν e and ν e Cooling phase: PNS cools down by emitting all flavors of neutrino Luminosity [1 51 erg/s] Average Energy [MeV] ν e burst Accretion Cooling ν e ν - e ν x ν e ν - e ν x 7 ν e 6 - νe x ν e 12 - νe x Time [ms] Time [s] Time [s] ν e ν - e ν x ν e ν - e ν x 5 / 24

6 GW emission of SNe As optical observations have found anisotropies in SN explosion, it is believed that there will be GW emission during SN explosion. There are many different mechanisms that can lead to GW emission in SN explosion. Rotating core collapse and bounce. This is the most extensively modeled mechanism. Nonaxisymmetric rotational instabilities. Postbounce convective and SASI. PNS core pulsation. Anisotropic neutrino radiation. 6 / 24

7 Rotating core collapse and bounce h+d (cm) TypeI TypeII TypeIII t-t bounce (ms) Figure: GW from rotating core collapse and bounce (Ott, Class.Quant.Grav. 26 (29) 631). D is distance. 1 kpc cm 7 / 24

8 Nonaxisymmetric rotational instabilities Figure: GW from nonaxisymmetric rotational instabilities (Ott, Class.Quant.Grav. 26 (29) 631). 8 / 24

9 Postbounce convection and SASI Figure: GW from postbounce convective and SASI (Ott, Class.Quant.Grav. 26 (29) 631). 9 / 24

10 Non-radial PNS pulsation h+d + (cm) s15. s t-t bounce (s) Figure: GW from PNS pulsation (Ott, Class.Quant.Grav. 26 (29) 631). 1 / 24

11 Anisotropic neutrinos E2 GW amplitude (matter) A 2 [cm] E2 GW amplitude (neutrinos) A 2 [cm] time after bounce [s] Figure: Matter (solid) and neutrino (dashed) contribution to GW from Mueller,Janka,Marek, ApJ 766 (213) 43. h + D = π sin2 θa E / 24

12 Merging binary stars GW emission is undetstood well. GW strength is much larger than that of SNe. Neutrino emission can be comparable to SNe. Two situations: Binary neutron stars. Black hole-neutron star system. 12 / 24

13 GW emission of merging BNS h +, [1-22 ] h +, [1-22 ] h +, [1-22 ] 2 L (a) M H t ret - t merge [ms] Figure: GWs of merging BNS 1 Mpc away. (Sekiguchi et. al., Phys.Rev.Lett. 17 (211) 5112) 13 / 24

14 Neutrino emission of merging BNS L ν [1 53 erg / s] L ν [1 53 erg / s] L ν [1 53 erg / s] (a) L ν e ν e ν x (b) M 5 (c) H t - t merge [ms] Figure: Neutrino luminosities of merging BNS. (Sekiguchi et. al., Phys.Rev.Lett. 17 (211) 5112) 14 / 24

15 Neutrino emission of merging BH-NS Table: Observed E (L ) and emitted E(L) averaged neutrino energies (luminosities) for an AD-BH and for a PNS. (Caballero et. al., Phys.Rev. D8 (29) 1234) E(MeV) E (MeV) E(MeV) L(ergs/s) L (ergs/s) Disk Disk PNS Disk( 1 53 ) Disk( 1 53 ) ν e ν e ν x ν x / 24

16 Detection of GW and neutrino signals If we only consider the astronomical events in the Galaxy and nearby SMC/LMC, both the neutrino and GW events can be observed (by JUNO and aligo, e.g.). If the astronomical event happens 1 Mpc away, then JUNO will observe no neutrino signal, while GW signal may still be detected by aligo. Core-collapse SN rate in the Galaxy and SMC/LMC is estimated to be about one per 3-5 years, while merging binary stars have much smaller rate. Figure: Merging binary stars rate in Galaxy. (LIGO, Class.Quant.Grav.27:1731,21) 16 / 24

17 GW detection ability Sh ( f ) [Hz 1/2 ] aligo 215 aligo 217 aligo 219 AdVirgo 217 AdVirgo Frequency [Hz] 17 / 24

18 Detection of GW from SNe The GW signals from SNe have typical frequencies of several hundred Hz, which is suitable for aligo to detect them. The GW amplitude from a SN 1 kpc away can be as large as 1 21, which is large enough for aligo. The signal-to-noise ratio (SNR) can be used to describe the detectability of GW. (SNR) 2 optimal = 4 h + (f) 2 + h (f) 2 df, S(f) 18 / 24

19 SNR of GW signal Figure: GW SNR of a SN 3.9 Mpc away (Ott, Class.Quant.Grav. 26 (29) 631). 19 / 24

20 Detection of neutrinos from SNe There will be about 1 4 neutrino events in JUNO for a SN 1 kpc away. 6 channels can be used to detect SN neutrinos. Figure: Result from JUNO yellowbook. 2 / 24

21 Detection of neutrinos from merging stars The luminosity and average energy of neutrinos are similar with that of SNe, so the events detected in JUNO are also similar. ν e + p n + e + ν + e ν + e SK(32 kton) UNO(58 kton) Hyper-K(1Mton) Amanda(68 OM) IceCube(48 OM) PNS(SK) Table: Neutrino events from a merging BH-NS system 1 kpc away (Caballero et. al., Phys.Rev. D8 (29) 1234). 21 / 24

22 Detection of GW from merging stars 1-2 (b) h eff (D = 1 Mpc) L M H LCGT adv.ligo bro.ligo f [khz] Figure: Effective amplitude of GW for merging BNS 1 Mpc away. (Sekiguchi et. al., Phys.Rev.Lett. 17 (211) 5112) 22 / 24

23 Summary and physics potential SNe in the Galaxy are good sources of both neutrino and GW signals. Merging binary stars are as good as SNe. However they are very rare in the Galaxy. GW and neutrino signals together can give constrains on SN explosion mechanism. GW has no dispersion, so the GW signals can provide accurate time information of SN explosion or star merging, which can be combined with neutrino signals to test something like absolute neutrino mass and Lorentz invariance. 23 / 24

24 Thanks! 24 / 24