Ian Harry Why were excited by compact binary mergers Short - PowerPoint PPT Presentation

Ian Harry

• Why we’re excited by compact binary mergers • Short introduction to gravitational waves and gravitational-wave observatories • Observing compact binary mergers with gravitational-wave facilities • What can we learn from gravitational-wave observations of compact binary mergers?

Image credit: NRAO and Chandra.harvard.edu

0.0 0.5 1.0 1.5 2.0 2.5 Neutron star-white dwarf systems B2303+46 B1911-5958A* J1909-3744 B1855+09 J1802-2124 B1802-07* J1748-2446J(Ter5J)* J1748-2446I(Ter5I)* J1713+0747 J1614-2230 B1516+02B* J1141-6545 J1012+5307 J0751+1807 J0621+1002 J0514-4002A* J0437-4715 J0024-7204H(47TucH)* Double neutron star systems B2127+11comp. B2127+11C B1913+16comp. B1913+16 J1906+0746comp. J1906+0746 J1829+2456comp. J1829+2456 J1811-1736comp. J1811-1736 J1756-2251comp. J1756-2251 B1534+12comp. B1534+12 J1518+4904comp. J1518+4904 J0737-3039B J0737-3039A 0.0 0.0 0.5 0.5 1.0 1.0 1.5 1.5 2.0 2.0 2.5 2.5 Neutron star mass [M ] Kiziltan et al. arXiv:1011.4291

0.0 0.5 1.0 1.5 2.0 2.5 Neutron star-white dwarf systems B2303+46 B1911-5958A* J1909-3744 B1855+09 J1802-2124 B1802-07* J1748-2446J(Ter5J)* J1748-2446I(Ter5I)* J1713+0747 J1614-2230 B1516+02B* J1141-6545 J1012+5307 J0751+1807 J0621+1002 J0514-4002A* J0437-4715 83 binary neutron star mergers in our galaxy every 1 million years J0024-7204H(47TucH)* Double neutron star systems B2127+11comp. B2127+11C B1913+16comp. B1913+16 J1906+0746comp. J1906+0746 J1829+2456comp. J1829+2456 J1811-1736comp. J1811-1736 J1756-2251comp. J1756-2251 B1534+12comp. B1534+12 J1518+4904comp. J1518+4904 J0737-3039B J0737-3039A 0.0 0.0 0.5 0.5 1.0 1.0 1.5 1.5 2.0 2.0 2.5 2.5 Neutron star mass [M ] Kalogera et al. ApJ. 601, L179 (2004)

• Binary pulsar PSR1913+16 o Pulsar provides a very accurate clock o Ideal “laboratory” for testing general relativity o Binary is losing energy as gravitational waves at precisely the rate predicted by general relativity 7 Figure from Weisberg+Taylor (2004).

Low mass X-ray binary (LMXRB) High mass X-ray binary (HMXRB) Image credit: ESA (left) NASA/ESA/Felix Mirabel (right)

Image credit: J. Orosz

Farr et al. ApJ 741, 103

Abbott et al. CQG 27, 173001 (2010)

Simulation courtesy of the Simulating 13 eXtreme Spacetimes (SXS) collaboration

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LIGO Hanford, WA LIGO Livingston, LA Virgo Cascina Italy 19

• Initial LIGO operated between 2002-2010 • Initial Virgo between 2007-2011 • No observations were made • Advanced LIGO will become is operational this year • Advanced Virgo will follow next year • At design sensitivity will be 10x more sensitive o 10x distance = 1000x more volume • Observatories in Japan and India hope to join in the 2020+ timescale. • The first direct observations of gravitational wave sources from colliding black holes and/or neutron stars are expected soon! 20

Advanced LIGO Advanced Virgo − 21 − 21 10 10 Early (2015, 40 − 80 Mpc) Early (2016 − 17, 20 − 60 Mpc) Mid (2016 − 17, 80 − 120 Mpc) Mid (2017 − 18, 60 − 85 Mpc) strain noise amplitude (Hz − 1/2 ) strain noise amplitude (Hz − 1/2 ) Late (2017 − 18, 120 − 170 Mpc) Late (2018 − 20, 65 − 115 Mpc) Design (2019, 200 Mpc) Design (2021, 130 Mpc) BNS − optimized (215 Mpc) BNS − optimized (145 Mpc) − 22 − 22 10 10 − 23 − 23 10 10 − 24 − 24 10 10 1 2 3 1 2 3 10 10 10 10 10 10 frequency (Hz) frequency (Hz) 100 Mpc = 326Mly = redshift (z) of 0.024 Aasi et al. 1304.0670

Mass ratio 4:1 2:1 1:1 ~ Average mass of the two components Image credit: Stevenson et al. 1504.07802

• Gravitational wave detectors are sensitive to sources from many directions � • Do not require “pointing” � • Makes source localization difficult � 24

GEO LIGO Virgo Hanford LIGO Livingston 25

5 × 10 − 3 0 1 2 3 4 prob. per deg 2 Singer et al. ApJ 795 (2014), 2, 105

1 . 5 × 10 − 2 0 . 0 0 . 5 1 . 0 prob. per deg 2 Singer et al. ApJ 795 (2014), 2, 105

2016 2017-8 2018 - ?? With a fourth observatory Aasi et al. 1304.0670

Aasi et al. 1304.0670 Abbott et al. CQG 27, 173001 (2010)

1.4 0.30 0.25 0.20 1.2 0.15 Χ 0.10 Χ NS � 0 0.05 m 1 � M � 1.0 0.00 � 0.05 1.5 2.0 2.5 3.0 Χ NS � 0.05 m 2 � M � 0.8 0.6 1.5 2.0 2.5 3.0 3.5 m 2 � M � Hannam, IH, et al. Astrophys.J. 766 (2013) L14

� ( m 1 × m 2 ) � 3 / 5 1.4 0.30 M = ( m 1 + m 2 ) × 0.25 ( m 1 + m 2 ) 2 0.20 1.2 0.15 Χ 0.10 Χ NS � 0 0.05 m 1 � M � 1.0 0.00 � 0.05 1.5 2.0 2.5 3.0 Χ NS � 0.05 m 2 � M � 0.8 0.6 1.5 2.0 2.5 3.0 3.5 m 2 � M � Hannam, IH, et al. Astrophys.J. 766 (2013) L14

� 3.2,3.2 � � 3.0 2.5 2.0 � 2,2 � � m 1 � M � 1:2 1.5 2.786 � 1.35,1.35 � � 1:4 � 1.0,1.0 � 1.0 � 1.741 1:10 1.219 0.5 0.871 0.0 0 2 4 6 8 10 m 2 � M � Hannam, IH, et al. Astrophys.J. 766 (2013) L14

8 Inspiral only � 7.3,7.3 � � 7 BBH region 6 Merger � � 5.7,5.7 � � ringdown m 1 � M � 5 4 3 2 2 4 6 8 10 12 14 m 2 � M � Hannam, IH, et al. Astrophys.J. 766 (2013) L14

3.5 0.90 0.85 3.0 0.80 Χ 2 0.75 2.5 0.70 0.65 m 1 � M � 2.0 0.60 0.5 1.0 1.5 2.0 2.5 1.5 � m 1 � M � 1.0 0.5 0.0 0 5 10 15 20 25 m 2 � M � Hannam, IH, et al. Astrophys.J. 766 (2013) L14

30 1 25 0.8 20 0.6 m 1 � 2 15 0.4 10 0.2 5 0 0 0 1 2 3 4 5 6 m 2 Littenberg, et al. 1503.03179

120 110 100 90 2 [ M � ] 80 m z 70 60 50 40 100 110 120 130 140 150 160 170 180 m z 1 [ M � ] Ghosh et al. arXiv: 1505.0560

Vitale et al. PRL 112, 251101 (2014)

Mandel et al. MNRAS 450, L85

Stevenson et al. 1504.07802

W. Del Pozzo, Phys. Rev. D 86, 043011 (2012)

0 . 08 TaylorT4 + all 0 . 07 (70 catalogs) δχ 3 = − 0 . 1 0 . 06 (30 catalogs) ) P (ln O modGR 0 . 05 GR 0 . 04 0 . 03 0 . 02 0 . 01 0 . 00 − 40 − 20 0 20 40 60 80 100 120 140 ln O modGR GR M. Agathos et al., Phys. Rev. D 89, 082001 (2014)

• We expect gravitational-wave astronomy to begin in the next years • Compact binary mergers are a key target for these systems • I hope to have given you a flavour of what we can learn from observing such systems

Any questions?

• Gravity is described as a warping of space and time o Caused by the mass and energy in the universe 44

Black hole space-time 45

Image: T. Carnahan (NASA GSFC) 46

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• How would we know when there is a black hole signal in data from LIGO and Virgo? • PROBLEM: The data is contaminated by other noise sources: seismic, thermal, human …. • PROBLEM: Unless the black holes are really close, data with a signal in it will look indistinguishable from data with no signal in it. • SOLUTION: Matched-filtering 49

• Optimal if looking for a known signal buried in noise. Wainstein and Zubakov “Extraction of signals from noise”, 1962 Allen et al. Phys.Rev. D85 (2012) 122006 Babak, … ,IH, et al. Phys.Rev. D87 (2013) 024033 50

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Time-frequency spectrograms showing power Loud simulated black hole merger A noise artifact 52

• Flag times of poor data quality • Use a variety of monitors to identify instrumental misbehaviour • Require “coincident” signal in several detectors • Make use of signal consistency tests 53