Signals(in(the(Dynamic(Radio(Sky( (from(lofar(and(other(telescopes(

Transcription

1 Signals(in(the(Dynamic(Radio(Sky( (from(lofar(and(other(telescopes( Michael(Kramer( Max-Planck-Ins3tut(für(Radioastronomie,(Bonn( Jodrell(Bank(Centre(for(Astrophysics,(University(of(Manchester(

2 Time(domain(astronomy( We(were(always(interested(in(3me-domain(sky( In(radio,(it(is(rela3vely(easy:(lots(of(easy(to(manipulate(photons(

3 S<ll,(even(in(the(radio(sky(it(took(a(while ( The(Haslam(et(al.(408-MHz(Survey((Effelsberg/Jodrell(Bank/Parkes)( (((((((((((((((Sta3c(image(is( hiding (a(lot(of(interes3ng(sources!(

4 If(Glyn(Haslam(had(had(beEer(<me(resolu<on (

5 The(success(story(of(<meGdomain(astronomy( The(discovery(of(pulsars(in(Cambridge(in(late(1967:(

6 The(success(story(of(<meGdomain(astronomy( Lots(of(extremely(useful(applica3ons:( (!(Plasma(physics(and(electrodynamics(under(extreme(condi3ons((!(Solid(state(physics:(super-dense(ma_er(&(Equa3on(of(State(!(Stellar(physics,(core(collapse,(binary(evolu3on((!(Interstellar,(intercluster((&(intergalac3c)(medium(!(Galac3c(structure(and(magne3c(field((!(High(precision(astrometry,(planetary(ephemerides((!(Gravita3onal(physics(and(tests(of(general(rela3vity(!(Gravita3onal(Wave(detec3on(!(Cosmology((

7 The(known(pulsar(popula<on( (Figure(by(C.(Ng)( >(2200((radio(pulsars( 1.40(ms(((PSR(J ad)( 8.50(s((((((PSR(J )( ( >(220((binary(pulsars( Orbital(period(range( 93.7(min(((PSR(J )( 5.3(yr((((PSR(J )( ( >20( extragalac<c (pulsars( (in(large(&(small(magellanic(clouds( ( Companions( MSS,(WD,(NS,(Planets( incl.(1(double(pulsar!(

8 The(parameter(space(of(the(dynamic(radio(sky( Keane(et(al.((2011)( Lorimer Burst L peak (Jy.kpc 2 ) Uncertainty Principle Crab ns Pulsar GRPs Pulsars J RRATs K GCRT K Coherent Emission Incoherent Emission Solar Bursts K 10 4 K Jupiter DAM ν.w (GHz.s) AD Leo TVLM 513 UV Ceti BD LP944 Figure 1. The transient phase space with known sources identified. This is simply a plot of the radio (pseudo-)luminosity L = SD 2 versus W,whereS is flux density, D is distance, is observing frequency and W is pulse width. As radio frequencies are in the Rayleigh-

9 profiles are far from stable in phase. Phase stability is usually implicitly assumed (in timing analysis software) when using high S/N profiles and templates. This assumption is inappropriate for single-pulse timing (as it is for slow pulsars timed using unstable average profiles) and will result in extra scatter in our timing residuals with a magnitude given by the size of the phase window wherein we see single pulses. As we will show this e ect is clear in our data (see Figure 4, as well as Figure 1a of Lyne et al. (2009)). summed to produce total intensity, i.e. Stokes I. The data are 1-bit digitised before being written to tape. The beginning of the observation is time-stamped according to the observatory clock, and is known to an accuracy of 80 ns. (ii) Search the data for single pulses. As described in K+10 the data are searched for strong, dispersed single pulses of radiation. Once detected, dedispersed single pulse profiles, are extracted from the data. (iii) Obtain TOAs. The templates used here are em- The(parameter(space(of(the(dynamic(radio(sky( Keane(et(al.((2011)( Lorimer Burst L peak (Jy.kpc 2 ) Uncertainty Principle Crab ns Pulsar GRPs Pulsars J RRATs K GCRT K Coherent Emission Incoherent Emission Solar Bursts K 10 4 K 10-5 UV Ceti BD LP944 Jupiter DAM ν.w (GHz.s) AD Leo TVLM 513 Figure 1. The transient phase space with known sources identified. This is simply a plot of the radio (pseudo-)luminosity L = SD 2 versus W,whereS is flux density, D is distance, is observing frequency and W is pulse width. As radio frequencies are in the Rayleigh- Jeans regime (h kt) wecandrawlinesofconstantminimum brightness temperature T B = (SD 2 /Jy kpc 2 )(GHz s/ W) 2 (see Keane (2010a) or Keane (2010b)). By(Tim(Hankins( Plotted are pulsars (Hobbs et al. 2004), RRATs, pulsar giant radio pulses (Cognard et al. 1996; Romani & Johnston 2001), flare stars (Bastian 1994; Richards et al. 2003; Osten & Bastian 2008; Osten 2008), auroral radio emission from the Sun and planets (Dulk 1985; Zarka 1998), GCRT (Hyman et al. 2006) and the so-called Lorimer burst (Lorimer et al. 2007), which we give only as a representative but not exhaustive list of sources. The boundary between coherent and incoherent emission is at K, due to inverse Compton cooling (Redhead 1994). The sensitivity of the PMSingle analysis (black lines) to individual bursts, is overplotted, from lowest to highest L, fordistancesof0.1, 1 and 10 kpc respectively. With the e ective area of the SKA the curves become lower by & 2ordersofmagnitudeinL (dotted lines). The LOFAR survey sensitivity curve (pink line) for a distance of 2 kpc is also shown.

10 profiles are far from stable in phase. Phase stability is usually implicitly assumed (in timing analysis software) when using high S/N profiles and templates. This assumption is inappropriate for single-pulse timing (as it is for slow pulsars timed using unstable average profiles) and will result in extra scatter in our timing residuals with a magnitude given by the size of the phase window wherein we see single pulses. As we will show this e ect is clear in our data (see Figure 4, as well as Figure 1a of Lyne et al. (2009)). summed to produce total intensity, i.e. Stokes I. The data are 1-bit digitised before being written to tape. The beginning of the observation is time-stamped according to the observatory clock, and is known to an accuracy of 80 ns. (ii) Search the data for single pulses. As described in K+10 the data are searched for strong, dispersed single pulses of radiation. Once detected, dedispersed single pulse profiles, are extracted from the data. (iii) Obtain TOAs. The templates used here are em- The(parameter(space(of(the(dynamic(radio(sky( Keane(et(al.((2011)( Lorimer Burst L peak (Jy.kpc 2 ) Uncertainty Principle Crab ns Pulsar GRPs Pulsars J RRATs K GCRT K Coherent Emission Incoherent Emission Solar Bursts K 10 4 K 10-5 AD Leo TVLM 513 UV Ceti BD LP944 Jupiter DAM ν.w (GHz.s) Lorimer(et(al.((2007)( Figure 1. The transient phase space with known sources identified. This is simply a plot of the radio (pseudo-)luminosity L = SD 2 versus W,whereS is flux density, D is distance, is observing frequency and W is pulse width. As radio frequencies are in the Rayleigh- Jeans regime (h kt) wecandrawlinesofconstantminimum brightness temperature T B = (SD 2 /Jy kpc 2 )(GHz s/ W) 2 (see Keane (2010a) or Keane (2010b)). By(Tim(Hankins( Plotted are pulsars (Hobbs et al. 2004), RRATs, pulsar giant radio pulses (Cognard et al. 1996; Romani & Johnston 2001), flare stars (Bastian 1994; Richards et al. 2003; Osten & Bastian 2008; Osten 2008), auroral radio emission from the Sun and planets (Dulk 1985; Zarka 1998), GCRT (Hyman et al. 2006) and the so-called Lorimer burst (Lorimer et al. 2007), which we give only as a representative but not exhaustive list of sources. The boundary between coherent and incoherent emission is at K, due to inverse Compton cooling (Redhead 1994). The sensitivity of the PMSingle analysis (black lines) to individual bursts, is overplotted, from lowest to highest L, fordistancesof0.1, 1 and 10 kpc respectively. With the e ective area of the SKA the curves become lower by & 2ordersofmagnitudeinL (dotted lines). The LOFAR survey sensitivity curve (pink line) for a distance of 2 kpc is also shown.

11 profiles are far from stable in phase. Phase stability is usually implicitly assumed (in timing analysis software) when using high S/N profiles and templates. This assumption is inappropriate for single-pulse timing (as it is for slow pulsars timed using unstable average profiles) and will result in extra scatter in our timing residuals with a magnitude given by the size of the phase window wherein we see single pulses. As we will show this e ect is clear in our data (see Figure 4, as well as Figure 1a of Lyne et al. (2009)). summed to produce total intensity, i.e. Stokes I. The data are 1-bit digitised before being written to tape. The beginning of the observation is time-stamped according to the observatory clock, and is known to an accuracy of 80 ns. (ii) Search the data for single pulses. As described in K+10 the data are searched for strong, dispersed single pulses of radiation. Once detected, dedispersed single pulse profiles, are extracted from the data. (iii) Obtain TOAs. The templates used here are em- The(parameter(space(of(the(dynamic(radio(sky( Keane(et(al.((2011)( Kramer(et(al.((2006)( Lorimer Burst L peak (Jy.kpc 2 ) Uncertainty Principle Crab ns Pulsar GRPs Pulsars J RRATs K GCRT K Coherent Emission Incoherent Emission Solar Bursts K 10 4 K 10-5 AD Leo TVLM 513 UV Ceti BD LP944 Jupiter DAM ν.w (GHz.s) Lorimer(et(al.((2007)( Figure 1. The transient phase space with known sources identified. This is simply a plot of the radio (pseudo-)luminosity L = SD 2 versus W,whereS is flux density, D is distance, is observing frequency and W is pulse width. As radio frequencies are in the Rayleigh- Jeans regime (h kt) wecandrawlinesofconstantminimum brightness temperature T B = (SD 2 /Jy kpc 2 )(GHz s/ W) 2 (see Keane (2010a) or Keane (2010b)). By(Tim(Hankins( Plotted are pulsars (Hobbs et al. 2004), RRATs, pulsar giant radio pulses (Cognard et al. 1996; Romani & Johnston 2001), flare stars (Bastian 1994; Richards et al. 2003; Osten & Bastian 2008; Osten 2008), auroral radio emission from the Sun and planets (Dulk 1985; Zarka 1998), GCRT (Hyman et al. 2006) and the so-called Lorimer burst (Lorimer et al. 2007), which we give only as a representative but not exhaustive list of sources. The boundary between coherent and incoherent emission is at K, due to inverse Compton cooling (Redhead 1994). The sensitivity of the PMSingle analysis (black lines) to individual bursts, is overplotted, from lowest to highest L, fordistancesof0.1, 1 and 10 kpc respectively. With the e ective area of the SKA the curves become lower by & 2ordersofmagnitudeinL (dotted lines). The LOFAR survey sensitivity curve (pink line) for a distance of 2 kpc is also shown.

12 profiles are far from stable in phase. Phase stability is usually implicitly assumed (in timing analysis software) when using high S/N profiles and templates. This assumption is inappropriate for single-pulse timing (as it is for slow pulsars timed using unstable average profiles) and will result in extra scatter in our timing residuals with a magnitude given by the size of the phase window wherein we see single pulses. As we will show this e ect is clear in our data (see Figure 4, as well as Figure 1a of Lyne et al. (2009)). summed to produce total intensity, i.e. Stokes I. The data are 1-bit digitised before being written to tape. The beginning of the observation is time-stamped according to the observatory clock, and is known to an accuracy of 80 ns. (ii) Search the data for single pulses. As described in K+10 the data are searched for strong, dispersed single pulses of radiation. Once detected, dedispersed single pulse profiles, are extracted from the data. (iii) Obtain TOAs. The templates used here are em- The(parameter(space(of(the(dynamic(radio(sky( L peak (Jy.kpc 2 ) Uncertainty Principle Crab ns Pulsar GRPs Pulsars Lorimer Burst J RRATs K GCRT 1745 Keane(et(al.((2011)( K Coherent Emission Incoherent Emission Solar Bursts K 10 4 K 10 7( s( Kramer(et(al.((2006)( 10-5 UV Ceti BD LP944 Jupiter DAM ν.w (GHz.s) AD Leo TVLM 513 Figure 1. The transient phase space with known sources identified. This is simply a plot of the radio (pseudo-)luminosity L = SD 2 versus W,whereS is flux density, D is distance, is observing frequency and W is pulse width. As radio frequencies are in the Rayleigh- Jeans regime (h kt) wecandrawlinesofconstantminimum brightness temperature T B =4 17 (SD 2 /Jy kpc 2 )(GHz s/ W) 2 (see Keane (2010a) or Keane (2010b)). By(Tim(Hankins( Plotted are pulsars (Hobbs et al. 2004), RRATs, pulsar giant radio pulses (Cognard et al. 1996; Romani & Johnston 2001), flare stars (Bastian 1994; Richards et al. 2003; Osten & Bastian 2008; 10 G9( Osten 2008), s( auroral radio emission from the Sun and planets (Dulk 1985; Zarka 1998), GCRT (Hyman et al. 2006) and the so-called Lorimer burst (Lorimer et al. 2007), which we give only as a representative but not exhaustive list of sources. The boundary between coherent and incoherent emission is at K, due to inverse Compton cooling (Redhead 1994). The sensitivity of the PMSingle analysis (black lines) to individual bursts, is overplotted, from lowest to highest L, fordistancesof0.1, 1 and 10 kpc respectively. With the e ective area of the SKA the curves become lower by & 2ordersofmagnitudeinL (dotted lines). The LOFAR survey sensitivity curve (pink line) for a distance of 2 kpc is also shown. Lorimer(et(al.((2007)( 10 G3( s(

13 The( LorimerGBurst ( A Bright Millisecond Radio Burst of Extragalactic Origin D. R. Lorimer, 1,2 * M. Bailes, 3 M. A. McLaughlin, 1,2 D. J. Narkevic, 1 F. Crawford 4 Pulsar surveys offer a rare opportunity to monitor the radio sky for impulsive burst-like events with millisecond durations. We analyzed archival survey data and found a 30-jansky dispersed burst, less than 5 milliseconds in duration, located 3 from the Small Magellanic Cloud. The burst properties argue against a physical association with our Galaxy or the Small Magellanic Cloud. Current models for the free electron content in the universe imply that the burst is less than 1 gigaparsec distant. No further bursts were seen in 90 hours of additional observations, which implies that it was a singular event such as a supernova or coalescence of relativistic objects. Hundreds of similar events could occur every day and, if detected, could serve as cosmological probes. REPORTS ratios greater than 4 with the use of a matched filtering technique (7)optimized for pulse widths in the range 1 to 1000 ms. The burst was detected in data taken on 24 August 2001 with DM = 375 cm 3 pc contemporaneously in three neighboring beams (Fig. 1) and was located ~3 south of the center of the Small Magellanic Cloud (SMC). The pulse exhibited the characteristic quadratic delay as a function of radio frequency (Fig. 2) expected from dispersion by a cold ionized plasma along the line of sight (8). Also evident was a significant evolution of pulse width across the observing frequency band. The behavior we observed, where the pulse width W scales with frequency f as W º f 4.8 ± 0.4,is consistent with pulse-width evolution due to interstellar scattering with a Kolmogorov power Lorimer(et(al.((2007)(

14 The( LorimerGBurst ( A Bright Millisecond Radio Burst of Extragalactic Origin D. R. Lorimer, 1,2 * M. Bailes, 3 M. A. McLaughlin, 1,2 D. J. Narkevic, 1 F. Crawford 4 Pulsar surveys offer a rare opportunity to monitor the radio sky for impulsive burst-like events with millisecond durations. We analyzed archival survey data and found a 30-jansky dispersed burst, less than 5 milliseconds in duration, located 3 from the Small Magellanic Cloud. The burst properties argue against a physical association with our Galaxy or the Small Magellanic Cloud. Current models for the free electron content in the universe imply that the burst is less than 1 gigaparsec distant. No further bursts were seen in 90 hours of additional observations, which implies that it was a singular event such as a supernova or coalescence of relativistic objects. Hundreds of similar events could occur every day and, if detected, could serve as cosmological probes. Where(does(it(come(from?( -(Localisa3on(for(single(dishes(limited(to(((( (((beamwidth( -(For(reliable(iden3fica3on(of(astrophysical( (((origin,(burst(should(appear(in(one(and( (((only(one(beam *( -(Mul3-beaming((poor-man s(image)(essen3al( REPORTS ratios greater than 4 with the use of a matched filtering technique (7)optimized for pulse widths in the range 1 to 1000 ms. The burst was detected in data taken on 24 August 2001 with DM = 375 cm 3 pc contemporaneously in three neighboring beams (Fig. 1) and was located ~3 south of the center of the Small Magellanic Cloud (SMC). The pulse exhibited the characteristic quadratic delay as a function of radio frequency (Fig. 2) expected from dispersion by a cold ionized plasma along the line of sight (8). Also evident was a significant evolution of pulse width across the observing frequency band. The behavior we observed, where the pulse width W scales with frequency f as W º f 4.8 ± 0.4,is consistent with pulse-width evolution due to interstellar scattering with a Kolmogorov power Lorimer(et(al.((2007)( ((((((((((((((((((((((((((((((((( * unless(it(is(extremely(bright (

15 Pulses(have(some(advantages:(Dispersion( The(interstellar(medium((ISM)(is(cold,(ionized(and(magne3zed(plasma( Pulses(propagate(with(a(frequency(dependent(group(velocity:( (((((((pulses(are(delayed(wrt(infinite(frequency(by:( Δt = e 2 2πm e c d n e dl D DM ν 2 0 ν 2 New(Ultra-Broadband(Receiver(for(100-m(telescope:( The( Dispersion(Measure ( ((((((DM(is(a(proxy(for(distance( (( ((((((in(par3cular(if(n e (l)(is(known( We(expect(a(characteris3c( (((((((1/ν 2 (dependence(for(astro-( ((((((((physical(pulses/bursts( Delay((ms)( Frequency((GHz)(

16 But(also:(Pulse(broadening(due(to(interstellar(scaEering( Eatough(et(al.((2013)/Spitler(et(al.((submi_ed)( 8.34 GHz 4.85 GHz 3.22 GHz 2.56 GHz Sca_ering(3me(scales(with(DM 2.2 (ν -4( Bhat(et(al.((2004)( Normalized Flux 1.63 GHz 1.55 GHz 1.42 GHz 1.34 GHz 1.27 GHz 1.19 GHz t (s) Example(here:(Magnetar(just(discovered(in(Galac3c(Centre((Eatough(et(al.,(Nature,(2013)( Fig. 2. Multi-frequency integrated pulse profiles. The blue curves are the measured profile. The red, green and black lines are the best fitted profile P obs (t), intrinsic Gaussian profile P g (t) and the scattering filter PBF e (t) respectively. ((((((((((((-(Highest(ever(measured(DM(=(1778±3(pc(cm -3( (-(highly(sca_ered(a(low(frequencies ( the pulsar jitter time scale at these frequencies. As expected, the intrinsic pulse width for the average profiles is much wider than the intrinsic width of the single pulses. No systematical structure is found in the fitting residuals, which indicates that the Gaussian modeling for the (((((((((((((((((( -(Temporal(broadening(related(to(angular(broadening( (also(observed (

17 But(also:(Pulse(broadening(due(to(interstellar(scaEering( Eatough(et(al.((2013)/Spitler(et(al.((submi_ed)( Bower(et(al.((submi_ed)( 8.34 GHz 4.85 GHz 3.22 GHz 2.56 GHz ( ( Normalized Flux 1.63 GHz 1.55 GHz 1.42 GHz 1.34 GHz 1.27 GHz An(astrophysical(signal(should(be(sca_ered(as(ν -4( 1.19 GHz t (s) Example(here:(Magnetar(just(discovered(in(Galac3c(Centre((Eatough(et(al.,(Nature,(2013)( Fig. 2. Multi-frequency integrated pulse profiles. The blue curves are the measured profile. The red, green and black lines are the best fitted profile P obs (t), intrinsic Gaussian profile P g (t) and the scattering filter PBF e (t) respectively. ((((((((((((-(Highest(ever(measured(DM(=(1778±3(pc(cm -3( (-(highly(sca_ered(a(low(frequencies ( the pulsar jitter time scale at these frequencies. As expected, the intrinsic pulse width for the average profiles is much wider than the intrinsic width of the single pulses. No systematical structure is found in the fitting residuals, which indicates that the Gaussian modeling for the (((((((((((((((((( -(Temporal(broadening(related(to(angular(broadening( (also(observed (

18 Faraday(rota<on(may(also(be(observed( Rota3on(measure:( RM = e 3 2 m 2 ec 4 Z d 0 n e B dl Earth( Pulsar( B R d 0 n eb dl R d 0 n e dl Amplitude( Wavelength((λ)( =1.23 µg Faraday(rota3on:( RM rad m 2 =RM 2 DM(and(RM(can(give(you(an(weighted(average(of(the(projected(magne3c(field:( DM cm 3 pc 1

19 ( Example,(again:(Galac<c(Centre(Magnetar( New(magnetar(=(probe(of(Galac3c(Centre(medium( Highest(DM(of(any(pulsar:(DM(=(1778±3(cm -3( pc(( Source(is(~(100%(linearly(polarized.( Rota3on(Measure(RM(=((-66960±50(rad(m -2 (( (((largest(rm(measured(in(galaxy((apart(from((sgr(a*)( LETTER doi: /nature12499 A strong magnetic field around the supermassive black hole at the centre of the Galaxy R. P. Eatough 1, H. Falcke 1,2,3, R. Karuppusamy 1, K. J. Lee 1, D. J. Champion 1, E. F. Keane 4, G. Desvignes 1, D. H. F. M. Schnitzeler 1, L. G. Spitler 1, M. Kramer 1,4, B. Klein 1,5, C. Bassa 4, G. C. Bower 6, A. Brunthaler 1, I. Cognard 7,8, A. T. Deller 3, P. B. Demorest 9, P. C. C. Freire 1, A. Kraus 1,A.G.Lyne 4, A. Noutsos 1, B. Stappers 4 & N. Wex 1 2 Amplitude( Wavelength((λ)( E a rt h( 1 Q U f (GHz) f (GHz)

20 The( LorimerGBurst (G(revisited( A Bright Millisecond Radio Burst of Extragalactic Origin D. R. Lorimer, 1,2 * M. Bailes, 3 M. A. McLaughlin, 1,2 D. J. Narkevic, 1 F. Crawford 4 Pulsar surveys offer a rare opportunity to monitor the radio sky for impulsive burst-like events with millisecond durations. We analyzed archival survey data and found a 30-jansky dispersed burst, less than 5 milliseconds in duration, located 3 from the Small Magellanic Cloud. The burst properties argue against a physical association with our Galaxy or the Small Magellanic Cloud. Current models for the free electron content in the universe imply that the burst is less than 1 gigaparsec distant. No further bursts were seen in 90 hours of additional observations, which implies that it was a singular event such as a supernova or coalescence of relativistic objects. Hundreds of similar events could occur every day and, if detected, could serve as cosmological probes. -(Appeared(only(in(one(beam( -(With(DM(of(375(pc(cm -3,(much(larger(than(Milky(Way,(( (((but(not(so(far(from(smc(pulsars( -(Dispersion(consistent(with(cold(plasma(law( -(Dynamic(range(limited,(but(pulse(appeared(to(be(( (((wider(at(lower(frequencies( -(Later(Burke-Spolaor(et.((2011)(detected(atmospheric( (((origin(of(similar(dm(but(not(quite(iden3cal(in(proper3es( REPORTS ratios greater than 4 with the use of a matched filtering technique (7)optimized for pulse widths in the range 1 to 1000 ms. The burst was detected in data taken on 24 August 2001 with DM = 375 cm 3 pc contemporaneously in three neighboring beams (Fig. 1) and was located ~3 south of the center of the Small Magellanic Cloud (SMC). The pulse exhibited the characteristic quadratic delay as a function of radio frequency (Fig. 2) expected from dispersion by a cold ionized plasma along the line of sight (8). Also evident was a significant evolution of pulse width across the observing frequency band. The behavior we observed, where the pulse width W scales with frequency f as W º f 4.8 ± 0.4,is consistent with pulse-width evolution due to interstellar scattering with a Kolmogorov power x Lorimer(et(al.((2007)( ((((

21 Meanwhile ( The( Keane-Burst ((Keane(et(al.(2012)( Discovered(in(archival(data(of(the(PMPS( Near(Galac3c(plane,(b=-4(deg( DM(of(746(pc(cm -3,(while(Milky(Way( (((((((less(than(533(pc(cm -3 (in(ne2001(model( ((((((((Cordes(&(Lazio(2001)( Consistent(with(cold-plasma(law( Considered:((-(giant(pulse(from(pulsar( (((((((((((((((((((((((((((((-(annihila3ng(black(hole( (((((((((((((((((((((((((((((-(other(models( Possibly(consistent(with(models(if(( (((((((NE2001(is(vastly(wrong( Problem:((in(the(plane(NE2001(some3mes( ((((((simply(not(reliable ( ( ((((((((((((((((((((((((((((((((((((((((((((((((((((Need(be_er(surveys(and(more(detec3ons!( ( Mon. Not. R. Astron. Soc. 425, L71 L75 (2012) On the origin of a highly dispersed coherent radio burst E. F. Keane, 1 B. W. Stappers, 2 M. Kramer 1,2 and A. G. Lyne 2 1 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, Bonn, Germany 2 School of Physics & Astronomy, Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL doi

22 The(allGsky( High((TimeGResolu<on(Universe(Survey ((HTRU)( Northern Survey Southern Survey Start date Summer 2010 Early 2008 Telescope Effelsberg-100m Parkes-64m Sky coverage δ > 0 δ < +10 Integration time Receiver Backend Low-lat: 1500 s Med-lat: 180 s High-lat: 90 s 7-beam 1.4-GHz receiver Pulsar Fast Fourier Transform Spectrometer (PFFTS) Low-lat: 4300 s Med-lat: 540 s High-lat: 270 s 13-beam 1.35-GHz receiver Berkeley-Parkes- Swinburne Recorder (BPSR) Bandwidth 300 MHz 340 MHz No. of channels Freq resolution 0.58 MHz 0.39 MHz Time resolution No. sky pointings 54 µs 64 µs ~ 180,000 ~ 43,000 Data sizes ~ 5 petabytes ~ 1 petabyte All-sky(high(3me(&(frequency(resolu3on(previously(unachievable( (Transient(sky(on(3mescale(down(to(tens(of(μs( (Higher(freq.(resolu3on(for(removing(interstellar(dispersion(

23 A(popula<on(of(Fast(Radio(Burst(at(Cosmological(Distances( Four(bursts(discovered(in(high-lat(part(of(HTRU((Thornton(et(al.,(Science,(2013)( All(at(high(galac3c(la3tudes(( b >(40(deg)( DMs(are(very(high:(500( (1100(pc(cm -3( One(very(bright(pulse(allows(further(studies( FRB FRB FRB FRB Beam right 22 h 34 m 21 h 03 m 23 h 30 m 23 h 15 m ascension ( J2000) Beam declination (J2000) Galactic latitude, b ( ) Galactic longitude, l ( ) UTC (dd/mm/yyyy hh:mm:ss.sss) 20/02/ :55: /06/ :33: /07/ :59: /01/ :11: DM (cm 3 pc) T T T T 0.3 DM E (cm 3 pc) Redshift, z (DM Host = cm 3 pc) Co-moving distance, D (Gpc) at z Dispersion index, a T T Scattering index, b 4.0 T 0.4 Observed width 5.6 T 0.1 <1.4 <4.3 <1.1 at 1.3 GHz, W (ms) SNR Minimum peak flux density S n (Jy) Fluence at 1.3 GHz, F (Jy ms) S n D 2 ( Jy kpc 2 ) Energy released, E (J) ~10 33 ~10 31 ~10 32 ~10 31 Thornton(et(al.((2013)(

24 A(very(bright(burst(allowing(detailed(studies( Thornton(et(al.(((2013)( DM((pc(cm G3 )( Band(delay((secs)( Observed(delay(( (DM(944(cm -3 (pc)(( MW((only(3-6%"(Extra-galac3c)( Host(galaxy(i=60 ( b ((deg)( Fig. S2. Measured DM for FRBs and known pulsars is plotted against the magnitude of Galactic latitude. The FRBs from this paper are shown as blue triangles, FRB and are shown as black squares, pulsars are indicated by red '+' symbols. The FRBs exhibit significantly higher dispersion than pulsars at similar separations from the Galactic plane. The pulsars with an apparent dispersion excess located at 30 < b < 45 are in the Magellanic clouds which provide an additional source of free electrons and dispersion. Redshiz,(z( Note:( Dispersion(index:(2.003(±(0.006( Sca_ering(index:(4.0(±(0.4( Inferred(distance:(z=(0.81( Other(bursts:(z(=(0.45( (0.96( Lorimer(burst:(z(=(0.3(! 8

25 How(to(derive(cosmological(distances?( Observed(DM(has(various(contribu3ons:((DM obs (=(DM MW (+(DM IGM (+(DM Host( All(but(Keane-burst(are(at(high(Galac3c(la3tudes,(so(that(Milky(Way(contribu3on(small( DM(from(host(is(unlikely(to(be(large((i.e.(from(central(part)(and(also(lever-arm(effect,( (((((i.e.(burst(emi_ed(at(host(at(higher(frequency(than(observed(redshized(at(earth,( (((((hence,(dm Host (also(small( Assuming(fully(ionised(IGM,(following(Ioka((2003)(&(Ionue((2004),(we(derive( ( z DM IGM(pc cm 3 ) 1000 Note(that(sca_ering(is(more(difficult(to(interpret,(as(situa3on(is(more(complex,( ((((since(it(depends(on(rela3ve(importance(of(turbulence(in(igm(and(host,(( ((((see(e.g.(macquart(&(koay((2013,(arxiv: )( Ideally,(we(want(to(iden3fy(host(to(study(the(IGM!((Unique(opportunity!( Ideally(also(in(full(polarisa3on(to(get(also(intergalac3c(magne3c(fields!(

26 What(is(the(best(strategy?( A(number(of(severe(uncertain3es(and(unknowns:( (((((((-((What(is(the(exact(posi3on?((Telescope(posi3on(unlikely(to(be(exact(on(target,( (((((((((((hence(observed(flux(density(is(likely(to(be(underes3mated.( (((((((-(What(are(the(spectra(and(luminosity(func3ons?((-(What(are(they?( (((((((-(How(severe(is(sca_ering,(in(par3cular(at(low(frequencies?( (((((((-(How(reliable(are(these(distances?( ( Best-effort (es3mates((for(fluence(of(3(jy(ms):(((r FRB( =(10000( +6000( (5000( sky(-1( day -1( ( Other(es3mates(differ(somewhat((but(are(consistent((e.g.(Hassall(et(al.(2013,(arXiv: )( ( At(the(moment,(best(consistent(with(ccSN(but(NS-NS(merger(also(possible( (something(else??( ( New(FoV(instruments(or(surveys(may(detect(a(lot( (depending(on(how(severe(sca_ering(is!( (((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((see(e.g.(hassall(et(al.(2013(and(lorimer(et(al.(2013)( (((((( Consider(also(imaging(surveys(as(an(alterna3ve((good(localisa3on( (poor(3me(resolu3on)(

27 How(many(FRBs(will(be(detected?( Hassall(al.(((2013)( 1(FRB/hour( 1(FRB/hour(

28 Radio(Pulsar(Searches(in(the(future,(already( Single(Dishes( Interferometers( SKA( Effelsberg( GMRT( SKA(Mid( Parkes( WSRT( SKA(Low( Arecibo( LOFAR( SKA(Aperture(Array(

29 Interna3onal(LOFAR(Telescope(

30 Sta3on(in(Effelsberg(was(the(first(of(9(interna3onal(sta3ons:(

31 The(Superterp(

32 Hassall( (Slide(by(J.(Hessels( LOFAR(core(

33 Slide(by(J.(Hessels( LOFAR(core(

34 Slide(by(J.(Hessels( LOFAR(core(

35 Slide(by(J.(Hessels( LOFAR(core(

36 Flexible(BeamGforming( As(this(is(a(sparse(aperture(array,(you(have(several(op3ons:( Figure(by(van(Leeuwen( Element(beam( Sta3ons(beam(s)( Tied-array(beam(s)(

37 LOFAR(Mul<Gbeaming( Hessels(

38 Heald,(Alexov(&(Hessels( High(spa<al(and(<me(resolu<on(

39 LOFAR(works,(e.g.(producing(excellent(polarisa<on(data( These(polarisa3on(profiles(from(LOFAR(are(the(best(ever(produced(at(these(frequencies(and,(in( several(cases,(the(only(polarisa3on(profiles(available(below(200(mhz( Slide(by(A.(Noutsos(

40 Team(effort:(LOFAR(Pulsar(Working(Group( Jason(Hessels((co-lead)( Ben(Stappers((co-lead)( Anya(Bilous( Thijs(Coenen( Sally(Cooper( Heino(Falcke( Jean-Mathias(Griessmeier( Tom(Hassall( Aris(Karastergiou( Evan(Keane( Vlad(Kondra3ev( Michael(Kramer( Masaya(Kuniyoshi( Joeri(van(Leeuwen( Aris(Noutsos( Maura(Pilia( Maciej(Serylak( Charlo_e(Sobey( Sander(ter(Veen( Joris(Verbiest( Patrick(Weltevrede( Kimon(Zagkouris( ASTRON(/(Universiteit(van(Amsterdam( University(of(Manchester( Radboud(Universiteit(Nijmegen( Universiteit(van(Amsterdam( University(of(Manchester( Radboud(Universiteit(Nijmegen( LPC2E/CNRS( University(of(Southampton( University(of(Oxford( MPI(für(Radioastronomie( ASTRON( MPI(für(Radioastronomie( MPI(für(Radioastronomie( ASTRON(/(Universiteit(van(Amsterdam( MPI(für(Radioastronomie( ASTRON( LPC2E/CNRS( MPI(für(Radioastronomie( Radboud(Universiteit(Nijmegen( MPI(für(Radioastronomie( University(of(Manchester( University(of(Oxford(

41 LOFAR(Pulsar(Survey( Great(field-of-view( Great(sensi3vity( 219(coherent(beams( 3(incoherent(beams( LOTAAS(G(LOFAR(TiedGArray(AllGSky(Survey( Slide(by(J.(Hessels(

42 Coherent( 3ed-array (beams( LOTAAS( Single( Poin3ng( 222(beams((FoVs)(at(once( First(SKA-like(pulsar(survey( Slide(by(J.(Hessels( Incoherent( sta3on (beam(

43 LOTAAS( Sparse( Sampling( Slide(by(J.(Hessels(

44 LOTAAS( Sparse( Sampling( Combined( Each(sky(posi3on(gets(3( observa3ons( Slide(by(J.(Hessels(

45 Fast(radio(transient(factories( Moon( Field-of-view( Parkes( Moon( Parkes( 0.6(sq.(deg.( Big(uncertainty:( Sca_ering(at(low( frequncies?( LOTAAS(will(tell(us!( 100x( LOFAR( Field-of-view( 60(sq.(deg.( Current(state-of-the-art( Slide(by(J.(Hessels(

46 The(Telescope( In(prepara<on(for(the(radio(telescope:(the(SKA!( For(pulsar(science(case(see(Kramer(et(al.((2004)(&(Cordes(et(al.((2004)( For(transient(science(case(see(Lazio(et(al.((2004)(

47 Sensi<vity(comparison( 12,000 Sensitivity*Comparison 10,000 Sensitivity:**Aeff/Tsys*****m 2 K 21 8,000 6,000 4,000 SKA2( SKA2 SKA1 MeerKAT LOFAR ASKAP evla 2,000 SKA1( ( LOFAR( EVLA( ,000 10, ,000 Frequency*MHz

48 Survey(speed(comparison( 100,000,000,000 10,000,000,000 Survey'Speed'SKA2 SKA2( 1,000,000,000 Survey''Speed':'Sensitivity 2 *FoV''''A 4 K 72 deg 2 100,000,000 10,000,000 1,000, ,000 10,000 1, SKA1(( LOFAR( EVLA( ,000 10, ,000 Frequency'MHz SKA2 SKA1 MeerKAT LOFAR ASKAP evla

49 Lots(of(data!( Already(exploi3ng(now:( Pulsar Discovery by Global Volunteer Computing B. Knispel,* B. Allen, J. M. Cordes, J. S. Deneva, D. Anderson, C. Aulbert, N. D. R. Bhat, O. Bock, S. Bogdanov, A. Brazier, F. Camilo, D. J. Champion, S. Chatterjee, F. Crawford, P. B. Demorest, H. Fehrmann, P. C. C. Freire, M. E. Gonzalez, D. Hammer, J. W. T. Hessels, F. A. Jenet, L. Kasian, V. M. Kaspi, M. Kramer, P. Lazarus, J. van Leeuwen, D. R. Lorimer, A. G. Lyne, B. Machenschalk, M. A. McLaughlin, C. Messenger, D. J. Nice, M. A. Papa, H. J. Pletsch, R. Prix, S. M. Ransom, X. Siemens, I. H. Stairs, B. W. Stappers, K. Stovall, A. Venkataraman E -(Neural(networks((Eatough(et(al.(2010)( -(Machine(learning((Lee(et(al.(2013)( -(Ci3zen(Science((Knispel(et(al.(2010,(2013)( About(1(Exabyte(per(day!!!!(

50 Synergies( Currently,(we(have(are(limited(in(follow-up(for(iden3fica3on(of(source(and(hosts( ASKAP/MeerKAT/SKA(and(LSST(will(see(the(same(hemisphere( Immediate(LSST(follow-up(of(SKA(triggers(affected(by(seasons( SKA-follow-up(of(LSST(triggers(can(be(quasi-instantaneous((see(all-sky!)( Currently,(transient(buffer(for(SKA(too(expensive(but(being(considered( Meanwhile,(we(improve(current(systems,(e.g.(Swinburne s( Heimdall (system(on(parkes( Further(collabora3ons:(MoUs(with(gravita3onal(wave(community( Upgrade(exis3ng(telescopes,(e.g.(100-m(+(LOFAR(single(sta3on(( Delay (seconds) Frequency (GHz)

51 Summary( Azer(50(years(of((fast)(3me-domain(studies(in(the(radio,(entering(a(new(era( Lots(of(things(are(lez(to(be(discovered,(incl.(a(whole(popula3on(of(cosmological(bursts( We(s3ll(don t(know(what(they(are!(but(lots!(one(every(10(second!(stay(tuned!( New(instruments((now(and(in(future)(are(a(game(changer(-(possible(by(digital(revolu3on!( We(should(try((and(will(be(able)(to(measure(polarisa3on(also((magn.(fields,(coherence )( SKA(and(LSST(will(be(an(ideal(combina3on(( ( ((((((((((((((((((((((( ((((((((((((((((((((((((Lots(to(be(done ((lots(of(new(phenomena(to(be(discovered ( ( ((((((((((((((((Btw,(exci3ng(SKA/LSST(synergies(also(for(studying(gravity(with(binary(pulsars(!( (((((((((((((((((((((((((((-(need(gaia(and(lsst(data(for(improving(model(of(galac3c(accelera3on( (((((((((((((((((((((((((((-(but(even(be_er(is(the(result(from(combining(radio(and(op3cal(data!(

52 Op<calGradio(synergies:(tes<ng(new(gravity(regimes( Example:(PSR(J (=(first(massive(NS(in(rela3vis3c(orbit((Lynch(et(al.(2013)( Combining(VLT,(Effelsberg,(Arecibo(&(GBT(data,(new(record(mass(measured:((((((((((( M=2.01±0.04(M #( (Antoniadis(et(al.,(Science,(2013)( (( Figure 1.1: Finding chart for PSR J from the SDSS navigate online tool 2 M WD =0.172±0.003(M #( Figure 1: Upper: Radial velocities of the WD companion folded modulo the orbital p (shown twice for clarity). Over-plotted (blue-line) is the best-fit orbit of the WD and the m orbit of the pulsar (green). Lower: Constraints on effective temperature, T e and surface ity, g for the WD companion to PSR J and theoretical WD models. The shaded depict the 2 2 min =1,4 and 9 (equivalent to 1, 2 and 3 ) intervals of our fit to the av spectrum. Dashed lines show the detailed theoretical cooling models of (27). Continuous depict tracks with thick envelopes for masses up to 0.2 M which yield the most conserv constraints for the mass of the WD (5). 8

53 Severe(constrains(on(tensorGscalar(gravity( We(can(already(rule(out(classes(of(tensor-scalar(theories(that(were(untestable( before( (much(more(possible(with(gaia((but(in(par3cular(with(lsst!( ((, P b =( 2.78 ± 0.45) ss 1 P b / P b GR =1.05 ± Antoniadis(et(al.((2013)(