A multi-wavelength investigation of candidate milli-second pulsars in unassociated $\gamma$-ray sources

Abstract

About one third of the 3033 $\gamma$-ray sources in the Third Fermi-LAT Gamma-ray Source Catalogue (3FGL) are unidentified and do not have even a tentative association with a known object, hence they are defined as unassociated. Among Galactic $\gamma$-ray sources, pulsars represent the largest class, with over 200 identifications to date. About one third of them are milli-second pulsars (MSPs) in binary systems. Therefore, it is plausible that a sizeable fraction of the unassociated Galactic $\gamma$-ray sources belong to this class. We collected X-ray and optical observations of the fields of twelve unassociated Fermi sources that have been classified as likely MSPs according to statistical classification techniques. To find observational support for the proposed classification, we looked for periodic modulations of the X-ray and optical flux of these sources, which could be associated with the orbital period of a MSP in a tight binary system. Four of the observed sources were identified as binary MSPs, or proposed as high-confidence candidates, while this work was in progress. For these sources, we present the results of our follow-up investigations, whereas for the others we present possible evidence of new MSP identifications. In particular, we discuss the case of 3FGL J0744.1-2523 that we proposed as a possible binary MSP based upon the preliminary detection of a 0.115 d periodicity in the flux of its candidate optical counterpart. We also found very marginal evidence of periodicity in the candidate optical counterpart to 3FGL J0802.3-5610, at a period of 0.4159 d, which needs to be confirmed by further observations.

arXiv comment17 pages, 7 figures, 2 tables, accepted for publication in MNRAS

References in corpus (38)

• The Sloan Digital Sky Survey: Technical Summary
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• The Swift X-ray Telescope
• The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
• The USNO-B Catalog
• The Swift Ultra-Violet/Optical Telescope
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• Fermi Large Area Telescope Second Source Catalog
• First Results from the Catalina Real-time Transient Survey
• The XMM-Newton Optical/UV Monitor Telescope
• The Catalina Surveys Periodic Variable Star Catalog
• GROND - a 7-channel imager
• The 2175 A dust feature in a Gamma Ray Burst afterglow at redshift 2.45
• A New Accretion Disk Around the Missing Link Binary System PSR J1023+0038
• On the polar caps of the 3 Musketeers
• The HELLAS2XMM survey: I. The X-ray data and the Log(N)-Log(S)
• PSR J1311-3430: A Heavyweight Neutron Star with a Flyweight Helium Companion
• Classification and Ranking of Fermi LAT Gamma-ray Sources from the 3FGL Catalog using Machine Learning Techniques
• A synthetic view on structure and evolution of the Milky Way
• Radio Searches of Fermi LAT Sources and Blind Search Pulsars: The Fermi Pulsar Search Consortium
• The Einstein@Home Gamma-ray Pulsar Survey. I. Search Methods, Sensitivity and Discovery of New Young Gamma-ray Pulsars
• Optical, ultraviolet, and infrared observations of isolated neutron stars
• Gamma-ray pulsars: a gold mine
• Discovery of an unidentified Fermi object as a black widow-like millisecond pulsar
• Hunting for treasures among the Fermi unassociated sources: a multi-wavelength approach
• Radio-quiet and radio-loud pulsars: similar in Gamma-rays but different in X-rays
• 1FGL J0523.5-2529: A New Probable Gamma-ray Pulsar Binary
• 2FGL J1653.6-0159: A New Low in Evaporating Pulsar Binary Periods
• Radio Follow-up on all Unassociated Gamma-ray Sources from the Third Fermi Large Area Telescope Source Catalog
• Multiband Diagnostics of Unidentified 1FGL Sources with Suzaku and Swift X-ray Observations
• A binary counterpart for 2FGL J2039.6-5620
• Chandra X-ray Observations of the Two Brightest Unidentified High Galactic Latitude Fermi-LAT gamma-ray Sources
• Discovery of a Redback Millisecond Pulsar Candidate: 3FGL J0212.1+5320
• Discovery of an ultracompact gamma-ray millisecond pulsar binary candidate
• A ROSAT Survey of Contact Binary Stars
• Searches for millisecond pulsar candidates among the unidentified Fermi objects
• Classifying Unidentified Gamma-ray Sources

Cited by in corpus (21)

• Optical spectroscopy and demographics of redback millisecond pulsar binaries
• Transitional millisecond pulsars
• Einstein@Home Discovery of the Gamma-ray Millisecond Pulsar PSR J2039-5617 Confirms Its Predicted Redback Nature
• Detection and timing of gamma-ray pulsations from the $707$ Hz pulsar J0952$-$0607
• The Einstein@Home Gamma-Ray Pulsar Survey II. Source Selection, Spectral Analysis and Multi-wavelength Follow-up
• Exploiting Orbital Constraints from Optical Data to Detect Binary Gamma-ray Pulsars
• A Deep Chandra X-ray Observatory Study of the Millisecond Pulsar Population in the Globular Cluster Terzan 5
• XMM-Newton detection and spectrum of the second fastest spinning pulsar PSR J0952-0607
• 4FGL J1120.0-2204: A Unique Gamma-ray Bright Neutron Star Binary with an Extremely Low Mass Proto-White Dwarf
• A Multi-wavelength search for Black Widows and Redbacks counterparts of candidate $\gamma$-ray millisecond pulsars
• Searching for optical companions to four binary millisecond pulsars with the Gran Telescopio Canarias
• The benefit of simultaneous seven-filter imaging: 10 years of GROND observations
• Periodicity search for Pulsar Binaries with TESS
• Nature of 4FGL J1838.2+3223: a flaring `spider' pulsar candidate
• Two black widow pulsars in the optical and X-rays
• 4FGL J1544.2$-$2554: a new spider pulsar candidate
• One of Everything: The Breakthrough Listen Exotica Catalog
• Search for the multiwavelength counterparts to extragalactic unassociated Fermi γ-ray sources
• High Energy Radiation from Spider Pulsars
• Deeper analysis of Fermi-LAT unassociated 4FGL J2112.5-3043 for possible identification
• Nature of 4FGL J2249.4+6229: Evidence for a redback system with a cool companion and low X-ray and $\gamma$-ray luminosities