Unraveling the nature of unidentified high galactic latitude FERMI/LAT gamma-ray sources with Suzaku

K. Maeda*, J. Kataoka, T. Nakamori, L. Stawarz, R. Makiya, T. Totani, C. C. Cheung, D. Donato, N. Gehrels, P. Saz Parkinson, Y. Kanai, N. Kawai, Y. Tanaka, R. Sato, T. Takahashi, Y. Takahashi

*この研究の対応する著者

研究成果査読

15 被引用数 (Scopus)

抄録

Here we report on the results of deep X-ray follow-up observations of four unidentified γ-ray sources detected by the Fermi/LAT instrument at high Galactic latitudes using the X-ray Imaging Spectrometers on board the Suzaku satellite. All of the studied objects were detected with high significance during the first three months of Fermi/LAT operation and subsequently better localized in the first Fermi/LAT catalog (1FGL). For some of them, possible associations with pulsars and active galaxies have subsequently been discussed, and our observations provide an important contribution to this debate. In particular, a bright X-ray point source has been found within the 95% confidence error circle of 1FGLJ1231.1-1410. The X-ray spectrum of the discovered Suzaku counterpart of 1FGLJ1231.1-1410 is well fitted by a blackbody with an additional power-law component. This supports the recently claimed identification of this source with a millisecond pulsar PSRJ1231-1411. For the remaining three Fermi objects, on the other hand, the X-ray observations performed are less conclusive. In the case of 1FGLJ1311.7-3429, two bright X-ray point sources were found within the LAT 95% error circle. Even though the X-ray spectral and variability properties for these sources were robustly assessed, their physical nature and relationship with the γ-ray source remain uncertain. Similarly, we found several weak X-ray sources in the field of 1FGLJ1333.2+5056, one coinciding with the high-redshift blazar CLASSJ1333+5057. We argue that the available data are consistent with the physical association between these two objects, although the large positional uncertainty of the γ-ray source hinders a robust identification. Finally, we have detected an X-ray point source in the vicinity of 1FGLJ2017.3+0603. This Fermi object was recently suggested to be associated with a newly discovered millisecond radio pulsar PSRJ2017+0603, because of the spatial coincidence and the detection of the γ-ray pulsations in the light curve of 1FGLJ2017.3+0603. Interestingly, we have detected the X-ray counterpart of the high-redshift blazar CLASSJ2017+0603, located within the error circle of the γ-ray source, while we were only able to determine an X-ray flux upper limit at the pulsar position. All in all, our studies indicate that while a significant fraction of unidentified high Galactic latitude γ-ray sources is related to the pulsar and blazar phenomena, associations with other classes of astrophysical objects are still valid options.

本文言語English
論文番号103
ジャーナルAstrophysical Journal
729
2
DOI
出版ステータスPublished - 2011 3 10

ASJC Scopus subject areas

  • 天文学と天体物理学
  • 宇宙惑星科学

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