Related papers: Multiwavelength Observations of Gamma-ray Binary C…
Gamma-ray binaries are orbital modulated gamma-ray sources in the Galaxy detected both at GeV and TeV energies. The high-energy radiation may come from the interaction of energetic electrons injected by a young pulsar and photons from the…
Gamma-ray binaries are binary systems where the energy flux peaks in the gamma-ray energy band. They harbour a compact object (a neutron star or a black hole) orbiting around a massive star that provides a strong radiation field. It is…
The non-repeating fast radio bursts (FRBs) could arise from catastrophic stellar explosions or magnetar giant flares, so relativistic blast waves might be produced in these events. Motivated by this, we here search for GeV counterparts to…
We report on the results of X-ray and radio follow-up observations of two GeV gamma-ray sources 2FGL J0923.5+1508 and 2FGL J1502.1+5548, selected as candidates for high-redshift blazars from unassociated sources in the {\it Fermi} Large…
In our previous study (Bhattacharyya et al., 2022), HD~54786, the optical counterpart of the MAXI J0709-159 system, was identified to be an evolved star, departing from the main sequence, based on comparisons with non-X-ray binary systems.…
We present new optical spectroscopy of 20 candidate counterparts of 17 X-ray sources in the direction of the M31 disc. By comparing the X-ray catalogue from the XMM-Newton survey of M31 with star catalogues from the Local Group Galaxy…
Transitional millisecond pulsars (tMSPs) in tight binary systems represent an important evolutionary link between low-mass X-ray binaries and radio millisecond pulsars. To date, only three confirmed tMSPs and a few candidates have been…
Giant X-ray outbursts, with luminosities of about $ 10^{37}$ erg s$^{-1}$, are observed roughly every 5 years from the nearby Be/pulsar binary 1A 0535+262. In this article, we present observations of the source with VERITAS at very-high…
There are only a few sources that are definitely known to be gamma-ray binaries. Two of these are listed as associations in the Fermi LAT Bright Source List. We are developing novel techniques to extract high signal-to-noise light curves of…
We have conducted a near-infrared spectroscopic survey of 47 candidate counterparts to X-ray sources discovered by the Chandra X-ray Observatory near the Galactic Center (GC). Though a significant number of these astrometric matches are…
We report the results of an analysis to identify candidates for very high energy (VHE; E > 100 GeV) emission from high-latitude (|b|>10) unassociated sources in the year-1 catalog under development by the Fermi large area telescope (LAT)…
Red dwarfs have been suggested to be among the possible astrophysical species accelerating particles and emitting TeV $\gamma$-rays. As an effort to search for the GeV $\gamma$-ray counterparts of the suggested TeV emission from eight red…
A large fraction of Fermi-Large Area Telescope (LAT) sources in the fourth Fermi-LAT 14 yr catalog (4FGL) still remain unidentified (unIDed). We continued to improve our machine-learning pipeline and used it to classify 1206 X-ray sources…
The final aim of this paper is to expand the sparse group of X-ray binaries with gamma-ray counterparts as laboratories to study high-energy processes under physical conditions that periodically repeat. A follow-up of a candidate system has…
We investigate the gamma-ray and X-ray emission from the transient gamma-ray source Fermi J0035+6131, which was discovered with the Fermi Large Area Telescope (LAT) near the Galactic plane at $b=1.3^\circ$, and we discuss potential…
The Fermi Gamma-ray Space Telescope, as an all-sky survey and monitoring mission, is producing daily/weekly sampled gamma-ray light curves for dozens of blazars and other high-energy sources. Highlights on MeV-GeV gamma-ray variability…
We present multiwavelength observations of the persistent Fermi-LAT unidentified gamma-ray source 1FGL J1417.7-4407, showing it is likely to be associated with a newly discovered X-ray binary containing a massive neutron star (nearly 2…
Gamma-ray emission in the TeV range has been detected by HESS from two X-ray binaries: PSR B1259-63 and LS 5039. In both, the early-type star provides large numbers of target photons for pair-production with TeV gamma-rays. This results in…
Perhaps the most extreme examples of "Active OB stars" are the subset of high-mass X-ray binaries -- consisting of an OB star plus compact companion -- that have recently been observed by Fermi and ground-based Cerenkov telescopes like HESS…
The central $2\times0.8$ deg$^2$ region of our Galaxy contains $\sim10,000$ X-ray point sources that were detected by a series of Chandra observations over the last two decades. However, the limited bandpass of Chandra below 8 keV hampered…