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Frbs) : Où En Sommes-Nous ? 10 ans de Fast Radio Bursts (FRBs) : où en sommes-nous ? Lucas Guillemot, pour l’AS SKA-LOFAR Journées de la SF2A 2019 Nice, 17 mai 2019 The early days of pulsar searching 1967: first pulsar discovery by Jocelyn Bell Burnell, with the Mullard radio telescope. Discovery of single pulses from pulsar B1919+21, data recorded on pen charts. Early 1970s: FFT & more powerful computers allowed larger bandwidths and integration times. No longer need to detect individual pulses! Hulse/Taylor Arecibo survey: first to use FFTs and digital systems. Discovery of the relativistic binary pulsar B1913+16. L. Guillemot, 17/05/19 2 The discovery of RRATs Early 2000s: ~2000 pulsars found by various large radio pulsar surveys. Not much single pulse searching done… McLaughlin et al. (2006): discovery of Rotating Radio Transients (RRATs) in a dedicated single pulse search! RRATs: short (few ms), sporadic but repeating (periodicity: few 0.1 to 1s) bursts of radio emission, at the same dispersion measures (DM). d DM = nedl <latexit sha1_base64="PRZJg901A8+Gkj2W4/9EnJDqQVA=">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</latexit> Z0 DM values suggest a Galactic origin. Most likely neutron stars. Difficult to find with FFTs! Motivated new searches of this kind. L. Guillemot, 17/05/19 3 The « Lorimer » burst From Lorimer et al. (2007) 1 Jy = 10-26 W m-2 Hz-1 Dispersed (DM ~ 375 pc cm-3), ~30-Jy, few ms duration burst detected near the direction of the Small Magellanic Cloud, with the Parkes radio telescope! L. Guillemot, 17/05/19 Search motivated by the discovery of RRATs. 4 6E.Petro↵, J.W.T. Hessels & D.R. Lorimer The « Lorimer » burst From Petroff et al. (2019). Data were one-bit digitized and include 96 frequency channels Fig. 1 The Lorimer burst (Lorimer et al.,2007,nowalsoknownasFRB010724),asseenin the beamrecorded of the every Parkes ms. multibeam The burst receiver was whereso bright it appeared that it brightest.saturated These the detector! data have been L. one-bitGuillemot, digitized 17/05/19 and contain 96 frequency channels sampled every millisecond. The burst has 5 3 aDMof375cm− pc. The pulse was so bright that it saturated the detector, causing a dip below the nominal baseline of the noise right after the pulse occurred. This signal was also detected in 3 other beams of the receiver. The top panel shows the burst as summed across all recorded frequencies. The bottom panel is the burst as a function of frequency and time (a ‘dynamic spectrum’). The red horizontal lines are frequency channels that have been excised because they are corrupted by RFI. survey at the Parkes telescope (HTRU; Keith et al., 2010). The discoveries by Thornton et al. (2013) had similar characteristics to the Lorimer burst, and implied an all-sky population of extragalactic radio pulses, which they termed ‘Fast Radio Bursts’, or FRBs. FRBs were immediately considered of great interest due to their large implied distances and the energies necessary to produce such bright pulses. As discussed further in 2, from the DMs of the four new FRB sources discovered by Thornton § et al. the bursts were estimated to have originated at distances as great as z =0.96 (luminosity distance 6 Gpc). With peak flux densities of approximately 1 Jy, this implied an isotropic energy of 1032 J(1039 erg) in a few milliseconds or a total 35 1 42 1 power of 10 Js− (10 erg s− ). The implied energies of these new FRBs were within a few orders of magnitude of those estimated for prompt emission from GRBs and supernova explosions, thereby leading to theories of cataclysmic and extreme progenitor mechanisms (see 9). § The excitement around the discovery by Thornton et al. led to increased searches through new and archival data not just at the Parkes telescope (Burke- Spolaor and Bannister, 2014; Ravi et al.,2015;Championet al.,2016),butalso at other telescopes around the world, resulting in FRB discoveries at the Arecibo Observatory (Spitler et al., 2014), the Green Bank Telescope (Masui et al.,2015), the Upgraded Molonglo Synthesis Telescope (UTMOST, Caleb et al.,2016b),the Identifying the source of perytons 5 The « Lorimer » burst (continued)Identifying the source of perytons 5 Quite a puzzling signal: • Implied distance of ~300 Mpc! • Extremely bright! (>109 brighter than RRATs) • Does not repeat! Figure 4. Number of narrow-emission spikes detected with the RFI monitor with S/N > 10 in a 60 MHz window around • Only seen at Parkes… 2.466 GHz between 18 January and 12 March, 2015. Figure 4. Number of narrow-emission spikes detected with the RFI monitor with S/N > 10 in a 60 MHz window around 2.466 GHz between 18 January and 12 March, 2015. Also seen at Parkes (Burke-Spolaor et al. 2011): Perytons… • Also only seen at Parkes… • Unlike Lorimer burst, seen in all 13 beams • Similar DMs: ~300-400 pc cm-3! • Similar durations: few ms. … later understood to be caused by a local microwave oven (Petroff et al., 2015)! FigureFigure 5. One 5. One of the of the bright bright perytons perytons generated generated during the the test test 3 3 L. Guillemot, 17/05/19 on 17on March 17 March with with DM DM = 410.3 = 410.3 cm cm− −pc.pc. RFI RFI monitor monitor data data at at the the 6 time oftime this of peryton this peryton is shown is shown in in Figure Figure 3. 3. tive events fall within the range 22.0+/-0.3 seconds, which tive events fall within the range 22.0+/-0.3 seconds, which is exceedingly unlikely to have been produced by manually is exceedinglyopening the unlikely oven. Rather, to have we been believe produced that the operator by manually had openingselected the oven. a power Rather, level of we less believe than 100%, that causingthe operator the mag- had Figure 2. RFI monitor spectra from Parkes for the perytons selectednetron a power power level to cycle of onless and than o↵ 100%,on a 22-second causing cycle, the mag- the Figure 2. RFIin the monitor week of spectra 19 January, from 2015. Parkes The for time the of peryton perytons has been period specified in the manufacturer’s service manual and in the week ofindicated 19 January, around 2015. the 2 The.3 2 time.5GHzrangebyblackarrows. of peryton has been netron power to cycle on and o↵ on a 22-second cycle, the ⇠ confirmed by measurement. It appears likely that over this indicated around the 2.3 2.5GHzrangebyblackarrows. period specified in the manufacturer’s service manual and ⇠ confirmedseven-minute by measurement. period the oven It appears produced likely a peryton that on over all this or most completions of this 22-second cycle but that the op- 3.5 The Peryton Cluster of 23rd June 1998 seven-minute period the oven produced a peryton on all or erator stopped the oven manually several times by opening most completions of this 22-second cycle but that the op- 3.5 The PerytonOf the 46 Cluster perytons detected of 23rd at June Parkes 1998 since 1998 some 16, the door, each time restarting the 22-second cycle. more than a third of the total, occurred within a period oferator stoppedKocz et the al. also oven noted manually a clustering several of event times times by modulo opening Of the 46 perytonsjust seven detected minutes, at on Parkes 23rd June since 1998. 1998 All some have a 16, DM con-the door,2 seconds each (their time Figure restarting 2). This the can 22-second be explained cycle. if the 22- more than asistent third of with the an total, origin occurred in the Woolshed. within a Kocz period et al. of (2012) Koczsecond et cycle al. also is derived noted from a clustering a stable quartz of event crystal times oscillator, modulo just seven minutes,noted that on 23rd the interval June 1998. between All consecutive have a DM events con- is clus-2 secondswhich (their is almost Figure certainly 2). This the case can as be the explained oven has ifa digital the 22- sistent with antered origin around in 22 the seconds. Woolshed. In this Kocz more et complete al. (2012) sample wesecondclock cycle display. is derived from a stable quartz crystal oscillator, noted that thefind interval that indeed between eight consecutiveof the 15 intervals events between is clus- consecu-which is almostHowever certainly we have been the unable case as to the repeat oven the has production a digital tered around 22 seconds. In this more complete sample we clock display. c 0000 RAS, MNRAS 000,000–000 find that indeed eight of the 15 intervals between consecu- However we have been unable to repeat the production c 0000 RAS, MNRAS 000,000–000 New FRBs from the HTRU survey Thornton et al. (2013): « a population of FRBs at cosmological distances », found in Parkes data taken as a part of HTRU. • Very high DMs (~550 to 1100 pc cm-3) • few ms durations • ~Jy peak flux density • Unlike Perytons, dispersion & scattering (from IGM and ISM) are as expected Fig. 1. The frequency-integrated flux densities for the four FRBs. The time resolutions match the level of dispersive smearing in the central frequency channel (0.8, 0.6, 0.9, and 0.5 milliseconds, respectively). 4 Implied rate: 10 / sky / day! Bottom right plot: the brightest FRB of the four (FRB 110220). Intrinsic width unresolved. Scattering tail increasing as ν-4.0+/-0.4 ! L. Guillemot, 17/05/19 7 Fig. 2. A dynamic spectrum showing the frequency-dependent delay of FRB 110220.
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