The Neutron Star Zoo Stephen C.-Y. Ng ( 吳志勇 ) HKU
Overview Introduction to neutron stars Different classes of neutron stars: Radio Pulsars MSPs Magnetars DINS CCOs Unification 6/12/2017 NAOC Stephen Ng
Evolution of Massive Stars Brooks/Cole Thomson Learning 6/12/2017 NAOC Stephen Ng
Extreme Physics Densest star: M 1.4 M, R 10 km 6/12/2017 NAOC Stephen Ng
Neutron Star 10km 6/12/2017 NAOC
Neutron Star 10km or 466,000 X 6/12/2017 NAOC Stephen Ng
Extreme Physics Densest star: M 1.4 M, R 10 km r~10 14 g/cm 3 World Population: 7 10 9 6/12/2017 NAOC Stephen Ng
Large Nucleus Nuclear density: 10-24 g/(10-13 cm) 3 A=294 A=10 57 6/12/2017 NAOC Stephen Ng
Extreme Physics Densest star: M 1.4 M, R 10 km Strongest magnetic fields in the Universe 10 4 G 0.5G 10 12-10 15 G 6/12/2017 Stephen Ng
Extreme Physics Densest star: M 1.4 M, R 10 km Strongest magnetic fields in the Universe Test of strong gravity and strong magnetism 6/12/2017 NAOC Stephen Ng
Gravitational Waves 6/12/2017 NAOC Stephen Ng
New Elements 6/12/2017 NAOC Stephen Ng
6/12/2017 Stephen Ng
6/12/2017 Stephen Ng
Radio Pulsars Neutron star was predicted by Baade and Zwicky in 1934 In 1967 (33 years later!) Jocelyn Bell discovered pulsed radio signal with period of 1.3s. LGM-1 6/12/2017 NAOC Stephen Ng
LGM-1 6/12/2017 NAOC Stephen Ng
Her PhD supervisor, Antony Hewish, awarded Nobel Prize in 1974 due to the discovery 6/12/2017 NAOC Stephen Ng
Pulsar = Rotating NS? Light crossing time 1.4ms 400km compact object Stable clocks: rotation, pulsation, binary Break-up period Ω 2 R GM R 2 ; Ω2 Gρ Rules out white dwarfs, as P > 1s. Black hole has no structure, accretion not periodic P ሶ > 0 rules out pulsation Rotating NS is the only choice 6/12/2017 NAOC Stephen Ng
Pulsars Rotating neutron stars Stable clocks 6/12/2017 NAOC Stephen Ng
Radio Pulsars 2000+ known in our Galaxy Period: 0.1-10s Broadband emission: radio, optical, X-rays, -rays =L / Ė < 1% Powered by rotation, spin down steadily 6/12/2017 NAOC Stephen Ng
Radio Pulsars 2000+ known in our Galaxy Period: 0.1-10s Broadband emission: radio, optical, X-rays, -rays =L / Ė < 1% Powered by rotation, spin down steadily 6/12/2017 NAOC Stephen Ng
Observational Properties Observable P t = P 0 + ሶ Pt + 1 2 ሷ Pt 2 + Characteristic age τ c = P 2 ሶ P Spin-down power ሶ E = d dt 1 2 Iω2 = Iωω ሶ = 4π 2 I Pሶ P 3 Surface dipole field B = 3.2 10 19 P ሶ P 1/2 G 6/12/2017 NAOC Stephen Ng
P- ሶ P Diagram 6/12/2017 NAOC Stephen Ng
P- ሶ P Diagram 6/12/2017 Stephen Ng
Pulsar Winds Where does pulsar rotational energy go? E ሶ > 10 35 erg/s < 10% in radiation (mostly -rays) > 90% in pulsar winds 6/12/2017 NAOC Stephen Ng
Pulsar Winds 6/12/2017 NAOC D. Page Stephen Ng
Pulsar Wind Nebula 6/12/2017 NAOC Stephen Ng
Ng et al. (2010) G319.9 0.7 ATCA X-ray + Radio Radio ATNF/CSIRO Kargaltsev et al. (2008); Ng et al. (2010) 6/12/2017 NAOC Stephen Ng
The Frying Pan 2000 km/s Longest pulsar tail > 20pc 6/12/2017 NAOC Ng et al. (2012)
PSR J1015 5719 6/12/2017 NAOC Ng et al. (2017)
The Snail (G327.1 1.1) Temim et al (2009) Ma, Ng et al. (2015) 6/12/2017 NAOC Stephen Ng
Hand of God (MSH 15-52) 6/12/2017 NAOC Stephen Ng
Hand of God (MSH 15-52) 6/12/2017 NAOC Stephen Ng Leung, Ng et al., in prep.
Hand of God (MSH 15-52) Leung, Ng et al., in prep. 6/12/2017 NAOC Stephen Ng
Classes of Neutron Stars Radio Pulsars MSPs Magnetars DINS CCOs 6/12/2017 NAOC Stephen Ng
P- ሶ P Diagram 6/12/2017 Stephen Ng
P- ሶ P Diagram 6/12/2017 Stephen Ng
Classes of Neutron Stars Radio Pulsars MSPs Magnetars DINS CCOs 6/12/2017 NAOC Stephen Ng
Millisecond Pulsars Period: a few ms First discovered in 1982 by Becker et al. (PSR B1937+21) Unification: old objects recycled via accretion 6/12/2017 NAOC NASA/Dana Berry
P- ሶ P Diagram 6/12/2017 Stephen Ng
Detecting Gravitational Waves Pulsar Timing Array 6/12/2017 NAOC D. Champion Stephen Ng
Gamma-ray Pulsars CGRO / EGRET 9 years 6 pulsars 1 possible MSP Fermi / LAT Since 2008 205 pulsars 93 MSPs more coming 6/12/2017 NAOC Stephen Ng
Fermi Pulsars Caraveo (2014) 6/12/2017 NAOC
Gamma-ray Pulsars 6/12/2017 NAOC Caraveo (2014)
Aliu et al. (2008) B-field at Light Cylinder B lc = R R lc 3 Bs R = 10km R lc = cp 2π 6/12/2017 NAOC Stephen Ng
Gamma-ray Pulsars 6/12/2017 Caraveo (2014)
PSR B1937+21 First MSP discovered Highest B lc =10 6 G, even higher than the Crab Non-thermal X-ray emission, giant pulses Aligned gamma-ray and radio pulses 6/12/2017 NAOC Stephen Ng Ng et al. (2014)
PSR B1937+21 First MSP discovered Highest B lc =10 6 G, even higher than the Crab Non-thermal X-ray emission, giant pulses Aligned gamma-ray and radio pulses co-located emission region new emission mechanism 6/12/2017 NAOC Stephen Ng
High-B lc MSPs 6/12/2017 NAOC Ng et al. (2014)
Classes of Neutron Stars Radio Pulsars MSPs Magnetars DINS CCOs 6/12/2017 NAOC Stephen Ng
P- ሶ P Diagram 6/12/2017 Stephen Ng
Magnetars: Extreme Pulsars First discovered in 1990s 23 confirmed (4 detected in radio) Extremely strong B 10 14 10 15 G > B QED High temperature, L Eሶ => powered by B-field decay Violent outbursts 6/12/2017 NAOC John Rowe Animations
Magnetars 0-10s 0-10Myr >10Myr Magnetar Radio pulsar Kouveliotou et al. (2003) 6/12/2017 NAOC Stephen Ng
Chandra X-ray Observatory 1E 1547.0 5408 ESA/Tiengo et al. 6/12/2017 NAOC Ng et al. (2011) Stephen Ng
Swift J1822.3 1606 6/12/2017 Scholz, Ng et al. (2012)
SGR 0501+4516 6/12/2017 NAOC Stephen Ng Mong & Ng (2017)
1E2259+596: Anti-Glitch 6/12/2017 Archibald, Kaspi, Ng et al. (2013, Nature)
1E 1048.1 5937: Delayed Torque Variation 1700 days 1700 days Delayed torque variation 100 days 6/12/2017 Archibald, Kaspi, Ng et al. (2015)
Magnetar Timing Properties Outbursts not always associated with glitches Pulse profiles 6/12/2017 NAOC Stephen Ng
Magnetar Timing Properties Outbursts not always associated with glitches Pulse profiles 6/12/2017 NAOC Stephen Ng
Magnetars: Extreme Pulsars First discovered in 1990s 23 confirmed (4 detected in radio) Extremely strong B 10 14 10 15 G > B QED High temperature, L Eሶ => powered by B-field decay Violent outbursts Unification? 6/12/2017 NAOC John Rowe Animations
Unification Magnetar-like outbursts from a high-b radio pulsar Low-field magnetar: SGR 0418+5729, J1822.3 1606 Radio emitting magnetars Surface temperature Magneto-thermal evolution 6/12/2017 NAOC Stephen Ng
High-B Radio Pulsars 6/12/2017 Stephen Ng
High-B Radio Pulsars Strong B-fields as magnetars But similar behavior as normal radio pulsars Radio to -ray pulsations Rotation-powered Transition objects, key to understand magnetars (Ng & Kaspi 2011 for a review) 6/12/2017 NAOC Stephen Ng
Young High-B PSRs PSR J1846-0258 P = 0.33s B = 4.9 10 13 G Age = 728yr PSR J1119-6127 P = 0.41s B = 4.1 10 13 G Age = 1610yr PSR B1509-58 P = 0.15s B = 1.5 10 13 G Age = 1700yr 6/12/2017 NAOC Stephen Ng
Magnetar-Like Outbursts PSR J1846-0258 2000 2006 6/12/2017 NAOC Gavriil et al. (2008)
PSR J1846 0258 / Kes 75 2000 2006 2009 Ng et al. (2008); Livingstone, Ng et al. (2011)
PSR J1119-6127/G292.2-0.5 XMM-Newton 6/12/2017 NAOC 10 Ng et al. (2012)
PSR J1119-6127/G292.2-0.5 XMM-Newton Göğüş et al. 2016 NAOC 10 Ng et al. (2012)
Hand of God (MSH 15-52) PSR B1509-58 B=1.5x10 13 G Hu, Ng, et al. (2017) 6/12/2017 NAOC
Thermal Luminosity 6/12/2017 Hu, Ng, et al. (2017)
Surface Temperature Mong & Ng (2017) 6/12/2017 NAOC Stephen Ng
Unification Magnetar-like outbursts from a high-b radio pulsar Low-field magnetar: SGR 0418+5729, J1822.3 1606 Radio emitting magnetars Surface temperature Magneto-thermal evolution Toroidal B-field 6/12/2017 NAOC Stephen Ng
Classes of Neutron Stars Radio Pulsars MSPs Magnetars DINS CCOs 6/12/2017 NAOC Stephen Ng
Dim Isolated Neutron Stars The Magnificent Seven INS / DINS / XDINS / NTEINS Nearby, thermally emitting isolated neutron stars P 10s B=1-3x10 13 G < 1kpc No radio emission 6/12/2017 NAOC
P- ሶ P Diagram 6/12/2017 Stephen Ng
Unification Old pulsars born with strong B-fields Radio beam missing us Relatively high surface temperature Nearby, otherwise undetected due to interstellar absorption 6/12/2017 NAOC Stephen Ng
Classes of Neutron Stars Radio Pulsars MSPs Magnetars DINS CCOs 6/12/2017 NAOC Stephen Ng
Central Compact Objects 7 known, found near the center of SNRs => young objects No radio, IR, optical emission, no PWN Thermal X-rays, high T, small R First CCO 6/12/2017 NAOC NASA/CXC/SAO/D.Patnaude et al.
Anti-Magnetars? Only 3 CCOs have pulsations detected Periods: 0.1-0.4s B-field: (3-10) 10 10 G 6/12/2017 NAOC Stephen Ng
P- ሶ P Diagram 6/12/2017 Stephen Ng
Anti-Magnetars? Only 3 CCOs have pulsations detected Periods: 0.1-0.4s B-field (3-10)x10 10 G CCOs as Anti-magnetars born with weak B? buried by fallback? Why no radio emission? 6/12/2017 NAOC Stephen Ng
Hunting for CCOs X-ray surveys: all pulsars coincident with supernova remnants (Bogdanov, Ng, & Kaspi 2014) all weak-field radio pulsars in the Galactic plane (Luo, Ng, et al. 2015) 6/12/2017 NAOC Luo, Ng, et al. (2015) Stephen Ng
P- ሶ P Diagram 6/12/2017 Stephen Ng
Grand Unification of NS Log B 14 Magnetars 12 10 CCOs (anti-magnetars) Radio Pulsars Isolated Neutron Stars 8 2 4 6 8 10 6/12/2017 NAOC Millisecond pulsars Kaspi (2010) Stephen Ng Log Age
Binary Pulsars Gamma-ray binaries PSR B1259 63 J2032+4127 / MT91 213 6/12/2017 NAOC Stephen Ng
Binary Pulsars Gamma-ray binaries PSR B1259 63 J2032+4127 / MT91 213 6/12/2017 NAOC Stephen Ng Ho, Ng, et al. (2017)
Future FAST Hard X-ray Modulation Telescope (HXMT) 慧眼 Neutron star Interior Composition ExploreR (NICER) erosita Large Observatory for X-ray Timing (LOFT) Square Kilometre Array (SKA) 6/12/2017 NAOC Stephen Ng