Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atnf.csiro.au/research/pulsar/orange10/pdf/ThierryReposeurOrange2010.pdf Дата изменения: Mon Sep 27 12:24:06 2010 Дата индексирования: Mon Feb 14 00:50:27 2011 Кодировка: Поисковые слова: ultraviolet

OBSERVATION of RADIO LOUD PULSARS with the Fermi-LAT -ray telescope

Thierry Reposeur CENBG Bordeaux, France on behalf of the Fermi-LAT Collaboration and the Pulsar Timing Consortium

Orange Pulsar Meeting 27-28 September 2010 Orange, NSW, Australia


pre-Fermi era 7 pulsars known to radiate -rays (6 EGRET, 1 COMPTEL)


Vela, the brightest Geminga, 1st radio quiet B1952, no cutoff

A too small population for an extensive study Fermi-LAT sensitity about 25x EGRET's expect many more pulsars. BUT very few gamma-rays per rotation (at GeV energies, Vela gives 1 photon every 100 rotations) typically 1000 "pulsed" gammas a year Radio observatories are very well suited to provide good timing solutions over a long period of time we can fold our 's, see what comes out Pulsar Timing Consortium (for the radio quiet pulsars Marianne's talk)
Thierry Reposeur, Orange Pulsar Meeting, 27-28 September 2010. Orange, NSW, Australia


The Pulsar Timing Consortium (PTC) one contact: smith at cenbg.in2p3.fr


Agreement (MoU) between several telescopes and the Fermi-LAT collaboration. (Parkes, GBT, NanГay, Jodrell + RXTE...) Initially, sources with dE/dt > 1034 erg/s are monitored 214 pulsars being « officially » followed (red)





but our 1st ms pulsar J0030+0451, has Edot=31033 erg/s gently ask for ephemerides not in the MoU

more than 750 ephemerides (blue) available at that time (mostly from NanГay and Jodrell) Note: Parkes alone in the Southern hemisphere great for the TeV PWN HESS connection (See Marie-HИlХne's talk here) Also The LAT Pulsar Search Consortium to search for radio pulsar in the Fermi-LAT sources (see Mike's talk)

Thierry Reposeur, Orange Pulsar Meeting, 27-28 September 2010. Orange, NSW, Australia


The exemple of J1048-5832 Abdo et al., ApJ, 706(2009)1331-1340 hardly seen by EGRET

The exemple of J1952+3252 Abdo et al., ApJ, 720(2010)26-40 energy cutoff !

No way without radio timing !

Thierry Reposeur, Orange Pulsar Meeting, 27-28 September 2010. Orange, NSW, Australia


The official map

First population study (Abdo et al., ApJS 187(2010)460-494) More up to date (not yet released) The LAT has detected 71 -ray pulsars in three (nearly equal) categories


Young radio-loud pulsars Young radio-quiet pulsars Radio-loud MSPs

Thierry Reposeur, Orange Pulsar Meeting, 27-28 September 2010. Orange, NSW, Australia


Pulsars in the first catalogue MSPs / blind search / radio selected / non detected

apart from MSPs we observe mainly young pulsars small age large B Large Edot small P

MSPs and "normal" have similar B

LC

same emission mechanisms (?)
Thierry Reposeur, Orange Pulsar Meeting, 27-28 September 2010. Orange, NSW, Australia


"DИjЮ vu..."

low altitude emission visible from one hemisphere and higher altitude (r > rNC) emission visible from the other. This is the "two pole caustic" (TPC) model (Dyks and Rudak 2003) intermediate between the polar cap (PC) and the Outer Gap (OG) picture

Power law + exponential cutoff energy spectra spectral energy cutoff not correlated with the surface magnetic field disfavors the Polar Cap model (-B cascades) slight correlation with B
LC

emission at "high altitude" non evidence of hyper-exponential cutoff "high altitude" emission
Thierry Reposeur, Orange Pulsar Meeting, 27-28 September 2010. Orange, NSW, Australia


Correlation between radio/gamma peak separation is observed as predicted by outer magnetosphere models (Outer Gap, Slot Gap).


The 0.2 range favors Outer Gap models the 0.4-0.5 range argues for Two Pole Caustic models

2 populations =0.2, =0.4-0.5 No dependence with Edot A full comparison will require detailed population models, which are being created.

Thierry Reposeur, Orange Pulsar Meeting, 27-28 September 2010. Orange, NSW, Australia


luminosity: L = 4fhd

2

f here assumed = 1 (geometry, what about MSPs ?) h energy flux measured by Fermi d distance to Earth, may have large uncertainties when evaluated from DM

LEdot 100% efficiency, L Edot1/2 constant voltage line
Seems to be L Edot

1/2

for Edot>10e36 erg/s


but still a big dispersion, errors due to 1) assumption on f , 2) distances
9
Thierry Reposeur, Orange Pulsar Meeting, 27-28 September 2010. Orange, NSW, Australia


numerous pulsars are


unidentified EGRET's associated with SNR/PWNe associated with TeV sources





10
Thierry Reposeur, Orange Pulsar Meeting, 27-28 September 2010. Orange, NSW, Australia


QUESTIONS

Why don't we see some young energetic pulsars ? Large background region broad lightcurve ? The LAT will continue to find new pulsars, but at a slower rate (sensitivity x2.2 after 5 years) New categories? High B-field pulsars Radio-quiet MSPs Young binary pulsars Individual MSPs in GCs

Thierry Reposeur, Orange Pulsar Meeting, 27-28 September 2010. Orange, NSW, Australia


CONCLUSIONS


The LAT has detected 71 -ray pulsars (not all published yet)


1/3 are young radio-loud pulsars 1/3 are young radio-quiet pulsars 1/3 are radio-loud MSPs

21 radio MSPs found in Fermi-LAT unidentified sources, some turn out to be also -ray emitters (pulsed !)


LAT statistics on -ray pulsars enabling population studies (phase resolved spectra) Hight altitude emission processes are favored (OG, SG) -ray beams scan over a large portion of the sky but Polar Cap still compatible with a few individuals
(Marie-HИlХne's PSR B1509-58)

send ephem files for your favorite pulsars if you think it is worth looking at it in -rays

Thierry Reposeur, Orange Pulsar Meeting, 27-28 September 2010. Orange, NSW, Australia