Unraveling the Nature of Unidentified High Galactic Latitude Fermi/LAT Gamma-ray Sources with Suzaku

Abstract

We report on the results of deep X-ray follow-up observations of four unidentified Fermi/LAT gamma-ray sources at high Galactic latitudes using Suzaku. The studied objects were detected with high significance during the first 3 months of Fermi/LAT operation, and subsequently better localized in the Fermi/LAT 1 year catalog (1FGL). Possible associations with pulsars and active galaxies have subsequently been discussed, and our observations provide an important contribution to this debate. In particular, an X-ray point source was found within the 95% confidence error circle of 1FGL J1231.1-1410. X-ray spectrum is well-fitted by a blackbody with an additional power-law. This supports the recently claimed identification of this source with a millisecond pulsar (MSP) PSR J1231-1411. Concerning 1FGL J1311.7-3429, two X-ray sources were found within the LAT error circle. Even though the X-ray spectral and variability properties were accessed, their nature and relationship with the gamma-ray source remain uncertain. We found several weak X-ray sources in the field of 1FGL J1333.2+5056, one coinciding with CLASS J1333+5057. We argue the available data are consistent with the association between these two objects. Finally, we have detected an X-ray source in the vicinity of 1FGL J2017.3+0603. This object was recently suggested to be associated with a newly discovered MSP PSR J2017+0603, because of the spatial-coincidence and the gamma-ray pulse detection. We have only detected the X-ray counterpart of the CLASS J2017+0603, while we determined an X-ray flux upper limit at the pulsar position. All in all, our studies indicate while a significant fraction of unidentified high Galactic latitude gamma-ray sources is related to the pulsar and blazar phenomena, associations with other classes of astrophysical objects are still valid options.

Accepted for publication in the ApJ

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Cited by in corpus (13)

• Fermi Large Area Telescope Fourth Source Catalog
• The Extragalactic Gamma-ray Sky in the Fermi era
• Characterizing the Optical Variability of Bright Blazars: Variability-Based Selection of Fermi AGN
• Unveiling the nature of the unidentified gamma-ray sources IV: the $\text{Swift}$ catalog of potential X-ray counterparts
• The Gamma-ray Blazar Quest: new optical spectra, state of art and future perspectives
• Refining the associations of the Fermi Large Area Telescope Source Catalogs
• Multiband Diagnostics of Unidentified 1FGL Sources with Suzaku and Swift X-ray Observations
• Chandra X-ray Observations of the Two Brightest Unidentified High Galactic Latitude Fermi-LAT gamma-ray Sources
• Toward Identifying the Unassociated Gamma-ray Source 1FGL J1311.7-3429 with X-ray and Optical Observations
• Optical spectroscopic observations of gamma-ray blazar candidates. IX. Optical archival spectra and further observations from SOAR and OAGH
• Suzaku X-ray Follow-up Observations of Seven Unassociated Fermi-LAT Gamma-ray Sources at High Galactic Latitudes
• Quasi-star jets as unidentified gamma-ray sources
• Suzaku Observation of Abell 1555 and Abell 1558: Searching for Non-thermal Emission from Large Scale Structure Formation