Persistent%20and%20Transient%20Blank%20Field%20Sources

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Persistent and TransientBlank Field Sources

• A. Treves Insubria University, Italy
• S. Campana Brera Observatory, Italy
• M. Chieregato Insubria University, Italy
  Zürich University, Switzerland
• T. Nelson Wisconsin University
• M. Orio Torino, Italy Wisconsin University

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Dim Isolated Neutron Stars (DINS)

• Residual Internal Energy
• Interaction with the surrounding
• N 108 109

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ROSAT DINS

• Blank Field Sources
• Low X-ray Luminosity Lx 1030 erg/s
• T lt 100 eV
• d 100 pc
• P 5 10 s
• Absorption lines lt 1 KeV

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Outline of the Contribution

• BFS in the ROSAT HRI Wavelet Catalogue
• (Chieregato et al., 2005, AA 444, 69)
• Progress in ROSAT BFS
• Transient Blank Field Sources
• Future perspectives

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BFS from HRI Catalogue

• Blank Field Sources
• fx gt 2.7 x 10-13 erg/s
• Nphgt25

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BFS HRI
Source Flux 10-13 erg cm-2s-1 Prob. s Cts fx / fopt Opt. s
0421-51 persistent 6.5 14.0 742 gt141 5.3
135718 transient 3.5 4.2 112 gt47 6.3
2007-48 transient 3.0 4.3 55 gt65 5.2
043315 transient 2.9 4.2 34 gt40 4.9
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0421-57X-ray position and blue image
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135718X-ray position and blue image
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0421-57Spectral fits for PSPC observation
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0421-57Power law spectral fits for PSPC
observation
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Progress in BSF HRI

• Reconsideration of 4 sources
• 043315 is a fake
• 135718, 2007-48 are not spiky
• X-ray (SWIFT Campana)
• 135718 fx lt 10-14 erg / s
• Optical (WIYN Orio)
• 135718 R gt 23.4

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If the two TBSF were real

• Total Number
• THRI 3 x 107 s
• O 0.2 deg2
• Isotropic N 105 y -1
• ? Extragalactic unlikely
• Gamma Ray Burst unlikely

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TBSF

• Non Collapsed Companions unlikely
• White Dwarfs
• Neutron Stars
• Relation with transient PSR?
• Hiccups?

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Progress

• Search for BFS with fx 10-14 erg / s
• (Chandra, XMM, SWIFT)
• X- and optical archives

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What we expect(dreams?)

• DINS accretion powered
• TBFS
• DINS cousins
• Isolated Black Holes
• Intermediate Mass Black Holes (ULX)