Pulsar Overview Kevin Stovall NRAO IPTA 2018 Student Workshop, 11 June, 2018 Pulsars Pulsars • ~2,700 pulsars known • Act as clocks, therefore provide a means for studying a variety of physical phenomena • Strongly affected by the interstellar medium (ISM) • There are many categories of pulsars (MSPs, RRATs, DNSs, mode-switching, nulling, etc.) • As a population are steep spectrum sources (alpha~-1.4) Some Pulsar Applications Populations Study of Interstellar Medium •Neutron Stars •Dispersion •Supernovae / Massive Stars •Scattering/Scintillation •Binaries •Faraday rotation •Millisecond Pulsars (MSPs) Extreme Environments Exotic Systems •Large B-field •Double Neutron Stars (DNSs) •Neutron Star Interior •Triple Systems •Tight Binary systems •Double Pulsar •Fast Spinning •Pulsar-BH Theories of Gravity Clocks •Tests of GR •Time Standard •Alternative Theories •Gravitational Waves Pulsars Pulse “Folding” Interstellar Medium Effects Dispersion 2 Delay DM ⌫− /d DM = 0 ne dl R From “Essential Radio Astronomy”, Condon & Ransom Galactic Electron Density Lazio & Cordes, 2002, astro-ph:0207156 Yao, Manchester & Wang, 2017, ApJ, 835 Scintillation Arcs Scattering Scintillation From “Handbook of Pulsar Astronomy”, Lorimer & Kramer ISM: Faraday rotation 2 PPA = – RM e3 d⇥ RM = 2 4 ne B dl 2ıme c 0 || R B =1:23—G RM h ||i DM Profile Temporal Stability Pulsar Timing P-Pdot Diagram Millisecond Pulsars (MSPs) primary secondary (a) (b) • Spin periods less runaway star than ~10 ms, binary disrupts weaker magnetic Supernova young pulsar fields, smaller mildly recycled pulsar spin-down rates binary survives young pulsar binary disrupts • Formed through secondary evolves (Roche Lobe overflow) accretion from a high-mass system Supernova companion star X-rays (therefore most low-mass system binary survives of them are in binaries: 2/3) millisecond pulsar - white dwarf binary double neutron star binary Lorimer, 2008, LRR, 11 Pulsar Spatial Distribution Pulsar Sky Distribution Pulsar Surveys (partial list) Center Frequency Sample Bandwidth Integration Survey Frequency Resolution Time Style Survey Region (MHz) Time (s) (MHz) (kHz) (us) All Arecibo Sky AO327 327 57/69 56/24 125/82 64 Drift Dec. between -1 & 38 CRAFTS 600 400 ? ? 40? Drift ? All GBT Sky GBNCC 350 100 24 82 120 Pointed Dec above -40 deg HTRU-N/S 1352 340 391 64 4200/540/270 Pointed All Sky Northern Sky LOTAAS 143 32 12 492 3600 Pointed Dec > about 0 deg Galactic Plane in PALFA 1375 323 336 65 268/180 Pointed Arecibo Dec Range Arecibo 327 MHz Drift Survey (AO327) - Deneva et al. 2013, ApJ, 775, 51 The Commensal Radio Astronomy FAST Survey (CRAFTS) Green Bank North Celestial Cap (GBNCC) - Stovall et al. 2014, ApJ, 791, 67 High Time Resolution Universe - South (HTRU-S) - Keith et al. 2010, MNRAS, 409, 619 High Time Resolution Universe - North (HTRU-N) - Barr et al. 2013, MNRAS, 435, 2234 LOFAR Tied-Array All-sky Survey (LOTAAS) - Coenen et al. 2014, A&A, 570, 60 Arecibo L-Band Feed Array Pulsar Survey (PALFA) - Cordes et al. 2006, ApJ, 637, 446 Targeted Pulsar Searches Fermi Unassociated Gamma-ray sources Locations of gamma-ray sources are searched using various radio telescopes. Drifting Subpulses & Nulling Mode Changing Rotating Radio Transients B1913+16: First Binary Pulsar Binary Parameters Keplerian Binary Parameters Orbital Period: PB Projected Semimajor axis: A1 Time of Periastron Passage: T0 Eccentricity: E Longitude of Periastron: OM Post-Keplerian Parameters 2 2 1 !˙ =6ıf (2ıMf ) 3 (1 e )− b b − 2 1 3 m2 m2 ‚ = e(2ıfb)− (2ıMfb) M (1 + M ) 192ı 5 P˙ = (2ı—f ) 3 F (e) b − 5 b r = m2 s = sin(i) Double Pulsar GR Tests PSR J0737-3039A/B Massive Pulsars & EOS PSR J1614-2230 PSR J0348+0432 Pulsar Mass = 1.97 +/- 0.04 Pulsar Mass = 2.01 +/- 0.04 Demorest et al. 2010, Nature, 467, 1081 Antoniadis et al. 2013, Science, 340, 448.