Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atnf.csiro.au/management/atuc/2011oct/science_meeting/docs/keith_atuc.pdf Дата изменения: Mon Oct 24 06:36:43 2011 Дата индексирования: Tue Feb 5 21:37:36 2013 Кодировка: Поисковые слова: п п п п п п п п п п п п п п п

THE HIGH TIME RESOLUTION UNIVERSE
A survey for pulsars & fast transients

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REVIEW OF HTRU

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SURVEY OVERVIEW
The High Time Resolution Universe survey for pulsars and fast transients -- HTRU An ambitious (~6000 hours) project to survey the entire Southern sky for radio pulsars and fast transients (<1s). Began in November 2008, still going strong!
See Keith et al (2010) for full survey description. (ATNF) Keith, Johnston, Burke-Spolaor*; (Swin) Bailes, van Straten, Levin, Coster, (JBO) Stappers, Bates*; (MPIfR) Kramer, Ng; (INAF) Possenti, Burgay, Milia

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SURVEY OVERVIEW
Survey is split into three areas: Low-latitude covers ± 3.5є from the plane Mid-latitude covers ± 15є from the plane High-latitude covers the remaining sky < 10є in dec There is a corresponding northern hemisphere survey at Effelsberg.

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DISCOVERY COUNT
High-lat
Observed Fraction Analysed Fraction
Simulated discoveries (MSPs) Actual Discoveries (MSPs)

Mid-lat
7312/7312

Low-lat
548/1230

11257/36583

30% ~few % 24 (13) 4 (1)

100% 75% 80 (28) 91 (20)

44% 3% 293 (33) 8 (0)

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MILLISECOND PULSARS
To date we have discovered 21 new MSPs, the first 12 have now been published with full timing solutions.
Bates et al. (2011), Bailes et al. (2011), Keith et al. (2011b)

Two of the MSPs have unique binary parameters not seen in any other pulsar. High quality, multi-frequency polarisation profiles give us new and valuable data for understanding the emission properties of MSPs.

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MILLISECOND PULSARS
To date we have discovered 21 new MSPs, the first 12 have now been published with full timing solutions.
Bates et al. (2011), Bailes et al. (2011), Keith et al. (2011b)

Two of the MSPs have unique binary parameters not seen in any other pulsar. High quality, multi-frequency polarisation profiles give us new and valuable data for understanding the emission properties of MSPs.

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"TRANSFORMATION OF A STAR INTO A PLANET IN A MILLISECOND PULSAR BINARY"
As part of the Mid-latitude survey at Parkes we discovered PSR J1719-1438 - a 5.7 ms pulsar in a 2.2 hour binary. Astonishingly the companion mass is ~1.2 Jupiter masses! Due to principally geometrical arguments we determined that this object must be a carbon white dwarf. Therefore a stellar mass object has undergone an incredible transformation, ejecting more than 99.9% of it's mass to become a planetary sized object.

Bailes et al. (2011)
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"DIAMOND PLANET"
Due to the exotic nature of the companion to PSR J1719-1438, it was described as a "diamond planet" in the media releases. Unsurprisingly this generated quite significant press coverage!

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VA R I A B L E & T R A N S I E N T DISCOVERIES

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THE SUDDEN APPEARANCE OF PSR J1622-4950
The very luminous PSR J1622-4950 discovered right in the middle of a well surveyed area of the Galactic plane This was quite surprising! Note that our new hardware doesn't help us with a 4.3 second pulse period. When we went back to the older surveys - no detection! Interesting...

Levin et al. (2010)
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VA R I A B I L I T Y O F P S R J1622-4950

1622-4950 at 17 GHz

Flux density variations of 1622-4950
Levin et al. (2010); Keith et al (2011a)
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FIRST DISCOVERY OF A R A D I O - L O U D X - R AY Q U I E S C E N T MAGNETAR
First discovery of a magnetar from its radio emission
Prior to this we knew of two magnetars for which we had seen radio emission, both discovered through X-ray flares. Will PSR J1622-4950 have detectable X-ray flares?

We characterise radio magnetar by:
Long period, large period derivative... high inferred magnetic field Large flux density variations Flat spectral index (observed > 100 GHz) Large variations in rotational period/period derivative Profile shape changes - total intensity and polarisation

Levin et al. (2010)
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`RRAT'S
"Rotating RAdio Transients" - pulsars which typically emit 1 pulse in hundreds of rotations. HTRU has discovered 16 previously unknown RRATS to date, many more candidates. It is becoming clear that RRATS are part of a broad spectrum of sporadic emission modes in radio pulsars.
Burke-Spolaor et al. (2011)
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`RRAT'S

J0912-48 is detectable as a "normal" pulsar but clearly shows occasional RRAT-like pulses. J1014-48 was detected in one cluster of 16 rotations of the star but never again re-detected. J1854-1557 shows nulling, mode changing, sub-pulse drifting and RRAT-like emission.

Burke-Spolaor et al. (2011)
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OTHER TRANSIENTS?

So far we have yet to observe any "Lorimer" type "extragalactic" events, though the focus has been in the Galactic plane so far. We have not detected any "Perytons", broadband dispersed radio pulses theorised to have atmospheric origin (Burke-Spolaor et al. 2011).

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CONCLUSION
-The HTRU is an ongoing all-sky
survey for radio pulsars at Parkes

-Many discoveries, including exciting
objects such as a magnetar, exotic binaries, RRATS, MSPs, etc.

-A significant focus on "single pulse"
analysis aiming to detect fast transients.

-Radio pulsars continue to surprise
through time-dependant variations on all time scales (ns -> decades)

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