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Recent results of pulsars and planets at UTR-2

Recent results of pulsars and planets at UTR-2

Vyacheslav Zakharenko
LOFAR Transients Key Project Meeting, Meudon, December 2011

transientskp

June 23, 2012
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  1. Recent Results of Pulsar and
    Transient Searching in Decameter
    Range.
    V. Zakharenko
    Institute of Radio Astronomy of NAS of
    Ukraine, Kharkiv

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  2. (Extremely) Low frequencies
    PRO CONTRA
    •  Radio emission cone
    broadening
    •  High DM, RM…
    resolution
    •  Possible “off-pulse”
    emission
    •  Increasing of flux density
    at low frequencies (for
    some pulsars)
    High Scattering in ISM.
    Big dispersion delay
    Bad Signal/Noise due to
    galactic background
    Interference ~ 70-80
    dB more than
    background.

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  3. 3
    Decametric North Sky Survey for Searching of Pulsars
    and Transients. Beam positions. Advantages:
    5 beams, tracking ~1 hour. Nearest beam data combining
    possibility
    Ў = 0° Ў = 60°

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  4. 4
    Parameters of survey (not far
    but…):
      δ = -10…90° (“full sky” ~ 40 days)
      DM = 0…30 pc/cm3 (or more…)
      P > 0.1 s
      UTR-2; Sum, Diff, Mul of «N-S» & «E-W»
      Band 16.5...33.0 MHz
      τacc
    agreed with τsc
    for nearest pulsars (8
    ms)

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  5. 5
    1st stage: redetecting
      δ = -10…90° full list
      DM = 0…30 pc/cm3 74 pulsars
      P > 0.1 s [ATNF pulsar catalog]
      UTR-2; Σ «N-S» & «E-W»
      Band 16.5...33.0 MHz
      τacc
    agreed with τ for nearest pulsars (8 ms)
      11-18 Oct 2010, 17-24 Jan 2011, 21-28 Mar 2011
      ~ 250 hours, 60% daytime observations.

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  6. 6
    Main goals of 1st stage:
    only ~10 PSRs with given parameters
    were detected in the decameter range
    - identification of disturbing factors for detection
    - ways to eliminate their influence
    - Fraction (Fr) of KNOWN pulsar (detected in
    the decameter range) for estimation:
    Fr * (N of PSRs)*(cone broad.-1) ≅ NEW PSRs

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  7. 7
    Rotational
    phase vs DM
    Rotational Phase

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  8. 8
    Redetection of PSR B0031-07
    Green ~ ½ S/N
    Yellow ~ 1/10 S/N
    Red - DM in one of
    pulsar catalog

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  9. 9
    Coordinates of 40 redetected (a) and 34
    non-redetected (b) pulsars

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  10. 10
    40 from 74 detected pulsars
    For 15 pulsars in bands 25±2 & 20±2 МHz and
    for 25 – (20…32 МHz): flux density, 50 and 10% intensity level,
    scattering time constant, exponent α sc 25 – 1000 MHz

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  11. Emission cone broadening W
    25
    /W
    100
    θ = Aν -α+θ0
    , [Thorsett, 1991ApJ, 377,263]
    Our results: 1.3 ... 2.6 times vs P

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  12. 12
    Pulsar detection rate: flux at
    400 MHz
    Comparison of upper
    detection limit of non
    detected pulsars (diamonds)
    and PSR B1133+16 (red
    line)

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  13. 13
    Raw spectrum,
    cleaned
    spectrogram and
    processed data of
    PSR B0525+21

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  14. SED spectrum, S/N vs
    time, compressed
    spectrogram and
    (apparent) dispersion
    delay with
    DM ≈ 2ž105 pc/cm3
    “Off-pulse” emission: directivity diagram(s).
    B0809+74

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  15. Pulses and
    1-dim
    ACF
    B0809+74

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  16. SED spectrum, S/N vs
    time, compressed
    spectrogram and
    (apparent) dispersion
    delay with
    DM ≈ 2ž105 pc/cm3

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  17. 17
    Conclusion:
      The high efficiency of pulsar and transient detection
    has been shown at decameter range
      Parameters of emission of more than 40 pulsars were
    refined or obtained for the first time
      New emission characteristics
      New sources
      ...

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  18. 18
    Why only ~ 10 known pulsars at
    lowest frequencies?
      Big dispersion delay (?) (DM=10 pc/cm3 ~100
    s in Δf=16…30MHz). But with optimum DM
    compensations it is NOT a problem
      Scattering in ISM. But in [Popov M.V. et al.
    Astronomy Reports. – 2006. – Vol. 50, – P.
    562–568. ] shown that for Crab pulsar
    ("plerion“, Galaxy plane, DM≈57 pc/cm3) at
    24 MHz τsc ≈ 3 s.

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  19. 19
    The relative radio emission cone broadening
    between 25 and 100 MHz vs period

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  20. 20
    Histogram: detected (solid line) and all (dash-
    dot line) pulsars depending on flux at 400 MHz.
    lin. log.

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  21. 21
    Mean and std. dev. for DM errors
    without and with truncation of
    maximum deviation

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  22. 22
    Error distribution of DM from ATNF
    compared to our observations. Allowable,
    significant and fatal errors for decameter
    wavelenght

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  23. 23
      Of course Signal/Noise!
    25 vs 100 MHz (ratio = 4)
    25000 vs 500 K (galactic background ratio ~
    4 2…3 times)
    0.5 vs 2 Jy (ratio ~ 4 1…2)
    Resulted ratio ~ 100…200 times. But Aeff
    UTR-2 =150 000 sq m
      Interference ~ 70-80 dB more than
    background. But high interference immunity and
    filtering let us to clean raw data.

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  24. 24
    DM comparison: catalog vs our observations
    № Name DM Err DM n Err № Name DM Err DM n Err
    1 B0031-07 11.38 8 10.896 10 21 B1508+55 19.613 20 19.622 10
    2 J0051+0423 13.9 1 13.936 10 22 B1530+27 14.698 18 14.706 10
    3 B0053+47 18.09 4 18.144 10 23 B1540-06 18.403 4 18.303 10
    4 B0148-06 25.66 3 25.661 10 24 B1604-00 10.682 5 10.688 10
    5 B0320+39 26.01 3 26.162 10 25 B1612+07 21.39 3 21.402 10
    6 B0329+54 26.833 10 26.783 10 26 B1633+24 24.32 4 24.540 10
    7 B0450+55 14.495 7 14.602 10 27 J1741+2758 29.3 6 29.146 10
    8 B0809+74 6.116 18 5.755 10 28 B1822-09 19.38 4 19.408 10
    9 B0823+26 19.454 4 19.474 10 29 B1839+56 26.698 11 26.804 10
    10 B0834+06 12.889 6 12.872 10 30 J1851-0053 24 4 24.556 10
    11 B0919+06 27.271 6 27.316 10 31 J1908+0734 11.104 11 11.234 10
    12 J0927+23 23 2 24.032 10 32 B1919+21 12.455 6 12.435 10
    13 B0940+16 20.32 5 20.354 10 33 B1929+10 3.180 4 3.180 10
    14 B0943+10 15.4 5 15.339 10 34 B1944+17 16.220 16 15.720 10
    15 B0950+08 2.958 3 2.972 10 35 B1952+29 7.932 7 7.870 10
    16 B1112+50 9.195 8 9.185 10 36 B2016+28 14.172 4 14.200 10
    17 B1133+16 4.864 5 4.846 10 37 B2110+27 25.113 4 25.114 10
    18 J1238+21 17.5 12 17.968 10 38 J2307+2225 7.08 3 6.842 10
    19 B1237+25 9.242 6 9.268 10 39 B2310+42 17.2758 13 17.256 50
    20 B1322+83 13.312 18 13.312 10 40 B2315+21 20.906 7 20.904 20

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  25. 25
    First results: some answers #

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  26. 26
    RF interference effect

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  27. 28
    PSR B2110+27
    ?

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  28. 29
    Redetection of PSR B1919+21
    DM, pc/cm3
    New = 12.455
    Old = 12.431
    Our = 12.435
    α sc
    < 3.90

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  29. 30
    SN number and “products”
    Evan Keane.
    http://arxiv.org
    /abs/1008.3693v1
    N/100years for SNs
    &
    PSRs, RRATs, XDINSs,
    Magnetars, CCOs

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  30. 31
    дщшщїщяїэѕѓцфђэщ PSR
    B1822-09
    ?

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