Les Pulsars gamma. avec GLAST

Transcription

1 Les Pulsars gamma Gamma-ray Pulsars avec GLAST and search for gamma-quiet ones with Fermi David Smith Centre d Etudes Nucléaires de Bordeaux-Gradignan ( CENBG - in2p3 - CNRS ) David A. Smith, for the Fermi LAT collaboration Centre d Études Nucléaires de Bordeaux-Gradignan (CENBG / IN2P3 / CNRS) smith@cenbg.in2p3.fr MODE Bordeaux, 16 Novembre 2010

2 June 11, 2008 Formerly "GLAST"

3 Large Area Telescope 30 MeV to 300 GeV The whole sky, 8 times per day: Known sources, as well as unexpected sources. Better localization than previous instruments. GBM 2 nd instrument Gamma-ray burst monitor

4 Fermi publications at

5 The Fermi LAT First Source Catalog released 14 Jan 2010, see Abdo, A. A. et al. 2010, ApJS, 188, 405 arxiv: Currently: 24 month catalog under study within the team. Cut-off spectra for pulsars. Improved diffuse model. Improved analysis < 200 MeV. 2 nd year catalog after Christmas. 5

6 10/10 PSR Census LAT Pulsars and growing 30 Young Radio-selected 13 MSP Radio-selected 26 Young γ-selected 6 γ-sel MSP γ/r pulse 14 γ-sel MSP R pulse

7 "First Fermi LAT Catalog of gamma-ray pulsars", Abdo et al 2010, ApJ Suppl 187, 460., arxiv: (Update) Preliminary Plot by Denis Dumora, Bordeaux

8 About the LAT pulsars Generally (but not always), two peaks separated by ½ rotations. Generally (but not always), gamma peak offset from radio. Exponential cut-offs at ~1 to ~3 GeV. Favors outer magnetospheric emission. MSPs resemble young pulsars. Not so true anymore. Now several MSPs where the gamma and radio peaks are aligned.

9 two examples Pulsed Gamma-rays from the MSP J with Fermi Abdo, A. A. et al. 2009, ApJ, 699, 1171 Pulsed gamma-rays from PSR J with the Fermi LAT Abdo, A. A. et al. 2009, ApJ, 700, 1059 " " offset between 2 γ peaks 1 st "millisecond" 1 st "young" "δ" radio-gamma offset

10 Blind search ("gamma-selected") Radio selected (found using rotation ephemerides) Millisecond pulsars 1 st Fermi γ-ray pulsar catalog",

11 Campaign to time 224 high Edot "Egret-like" pulsars. Nançay, Jodrell Bank, Parkes "gave" us another 500 ephemerides. Westerbrok, Urumqi, GMRT-India also involved. If you need rotation ephemerides, contact us. Excellent working relation with the radio and X-ray pulsar experts. Parkes (Australia) Jodrell Bank (England) Nançay (France) RXTE A&A 492, 293 (2008)

12 β LAT spectra for PSR J Abdo, A. A. et al. 2009, ApJ, 700, 1059

13 Phase-resolved spectroscopy. P0 = 237 ms 300 µs/bin (we see a structure smaller than 10 µs for one MSP) Geminga pulsar with Fermi LAT Abdo, A. A. et al. 2010, ApJ, 720, 272

14 Deep searches for radio counterparts to pulsars discovered in gamma-ray blind period searches. Abdo, A. A. et al. 2010, ApJ, 711, 64 P.S. Ray et al, ApJ submitted. arxiv: Upper limits Faintest ever!

15 Precise Gamma-Ray Timing and Radio Observations of 17 Fermi Gamma-Ray Pulsars P.S. Ray et al, ApJ submitted. arxiv: Timing residuals of Fermi rotation ephemerides are of order of milliseconds. Eight gamma-ray pulsars discovered in blind frequency searches of Fermi LAT data Saz Parkinson, P. M. et al. 2010, ApJ accepted. arxiv: Blind search pulsar #25 found last week.

16 Gamma-ray luminosity versus spindown power 5 gamma MSPs using Nançay -- 3 new! young, radio-selected young, blind-period search millisecond pulsars

17 f Ω : total flux / flux beamed along one line of sight radio emission cone Fan-like gamma beam from "outer" or "slot" gap? Radio vs gamma pulse profiles Powerful model discriminant Below left: ζ vs phase ϕ for a "slot gap" model. Below right: Cut across some line-of-sight ζ. γ-ray emission fan beam

18 Search for gamma-quiet pulsars what are the black dots at high Edot? (Update) Preliminary Plot by Denis Dumora, Bordeaux

19 Search for gamma-quiet pulsars Two purposes: 1) Double-checking our gamma pulsar searches "Leave no stone unturned" Timing ephemerides okay? Closer look at distances, backgrounds of "interesting" pulsars. 2) Additional test of emission models! Gamma quiet pulsars should occupy a little piece of α,ζ space. Check the angles (e.g. rotating vector model using radio polarization) Check the numbers of gamma-loud vs gamma-quiet pulsars. The "2 nd Fermi Catalog of γ-ray pulsars" (Spring 2011?) will include upper limits for pulsars with large expected signal-to-noise. Signal: ö/d² Noise: all other gamma sources (diffuse + neighbors) Comparisons with model syntheses in progress. (e.g. Watters & Romani 2010, ApJ submitted, arxiv: )

20 Rank PSRJ Edot (erg/s) Dist1 (kpc) b (deg) Two pulsars with ö> 1E38 erg/s, unseen in gamma rays. They're in the LMC! Just too far Abdo, A. A. et al. 2010, A&A, 512, A7 Here: 1E35 < ö < 1E38 erg/s, ranked by ö/d² J1740 wasn't getting timed! J1617 very difficult to time Parkes gave up. J1357 recovering from a big glitch. A few showing evidence for signals, at the 3 to 4 σ level. Others may be good "gamma quiet" candidates. Constrain α,ζ from radio polarization, calculate f Ω, and study gamma-ray upper limit. 14 J E J E J E J E J E J E J E J E J E J E J E J E J E J E J E J E Aitoff projection of LAT 5σ sensitivity (log photon flux, ph /cm²/s) for 6 months of sky-survey, for pulsar spectra with typical differential photon indices and exponential cutoff energies. (Figure 9 from "1 st Psr catalog".)

21 PSRs J0248 & J2240, Theureau et al, A&A in press (2010) Excerpt from "6 Fermi pulsars" by Weltevrede et al. 2010, ApJ, 708, 1426

22 Excerpt from "6 Fermi pulsars" by Weltevrede et al. 2010, ApJ, 708, 1426

23 At this point in the talk I showed the RVM explanation by Simon Johnston and Aris Karastergiou from the Barcelona pulsar conference in April

24 Conclusion Fermi LAT seeing a variety of pulsars in a variety of environments. Pulsars are the dominant gamma-ray foreground. High quality Fermi LAT and radio measurements constraining models. Des Bordelais à Nançay, le 29 juin 2006 Lucas Damien Moi Denis Gregory Ismaël Marie-Helène Marianne et Thierry ne sont pas sur la photo

25 Back-up slides See publications at

26 About those distances PSR J : (l,b) = 137, 0.7 DM = 370 pc/cm 3 NE2001: > 43.5 kpc We argue for kpc (said 2 to 9 in catalog) PSR J : (l,b) = 107, -0.1 DM = pc/cm 3 NE2001: kpc We argue for 7.7±0.7 kpc 9.2 kpc Reid et al, ApJ 700, 137 (2009) "anatomically correct" Also APOD 2008 July 11

27 Trois façons d'estimer les angles: 1. L'orientation ζ peut venir d'images du PWN en rayons X. 2. Comparaison des courbes de lumière gamma avec les modèles ("Atlas"). 3. α, β peuvent venir de mesures de la polarisation radio et, par exemple, le RVM = Rotating Vector Model

28 This slide Roger Romani. An Atlas for Interpreting Gamma-Ray Pulsars Watters, Kyle P. et al. 2009, ApJ, 695, 1289 arxiv:

29 Gamma-ray and Radio Properties of Six Pulsars Detected by the Fermi Large Area Telescope P. Weltevrede, A.A.Abdo, et al, ApJ accepted, posted to arxiv this morning.

30 Nature 463, 147, 14 January 2010 The new MSPs have different selection biases. "Treasure map". Well-distributed on the sky.