First author: Samuel J. Swihart
We present the discovery of a new optical/X-ray source likely associated with the Fermi $\gamma$-ray source 4FGL J1408.6-2917. Its high-amplitude periodic optical variability, large spectroscopic radial velocity semi-amplitude, evidence for optical emission lines and flaring, and X-ray properties together imply the source is probably a new black widow millisecond pulsar binary. We compile the properties of the 41 confirmed and suspected field black widows, finding a median secondary mass of $0.
First author: Miguel Araya
The discovery of a non-thermal radio ring of low surface brightness about one degree in diameter has been recently reported around the location in the sky of the Calvera pulsar, at a high Galactic latitude. The radio properties point to it likely being a new supernova remnant (SNR), G118.4+37.0. We report an analysis of almost 14 years of observations of this region by the gamma-ray Large Area Telescope onboard the Fermi satellite.
First author: Fabrizio Tamburini
In our previous work [Tamburini and Licata (2017)] we discussed the hypothesis that the ultrafast periodic spectral modulations with frequency $f_S \simeq 0.61$ THz found by Borra and Trottier (2016) in $236$ main sequence stars from a sample of $2.5$ million spectra of galactic halo stars of the Sloan Digital Sky Survey were due to axion-like dark matter piled up in the center of these stars.
First author: Jacques P Vallee
To pinpoint the peak location of the synchrotron total intensity emission in a spiral arm, we use a map of the spiralarm locations (from the observed arm tangent). Thus In a typical spiral arm in Galactic Quadrant I, we find the peak of the synchrotron radiation to be located about 220 +/-40 pc away from the inner arm edge (hot dust lane) inside the spiral arm.
First author: Walter Dehnen
We present a family of analytical potential-density pairs for barred discs, which can be combined to describe galactic bars in a realistic way, including boxy/peanut components. We illustrate this with two reasonable compound models. Computer code for the evaluation of potential, forces, density, and projected density is freely provided.
arxiv link
pdf link
First author: Zi-Qing Xia
The fast evolving TeV-PeV transients and their delayed GeV-TeV cascade emission in principle server as an ideal probe of the inter-galactic magnetic fields which are hard to be measured by other methods. Very recently, LHASSO has detected the very high energy emission of the extraordinary powerful GRB 221009A up to $\sim 18$ TeV within $\sim 2000$ s after the burst trigger. Here we report the detection of a $\sim 400$ GeV photon, without accompanying prominent $\gamma$ rays down to $\sim 2$ GeV, by Fermi-LAT in the direction of GRB 221009A at about 0.
First author: Chenxu Liu
We report an Active Galactic Nucleus (AGN) with extremely high equivalent width (EW), EW(LyA+NV,rest)>921 AA in the rest-frame, at z~2.24 in the Hobby-Eberly Telescope Dark Energy Experiment Survey (HETDEX) as a representative case of the high EW AGN population. The continuum level is a non-detection in the HETDEX spectrum, thus the measured EW is a lower limit. The source is detected with significant emission lines (>7sigma) at LyA+NV, CIV, and moderate emission line (~4sigma) at HeII within the wavelength coverage of HETDEX (3500 AA - 5500 AA).
First author: K. Suchomska
Our goal is to determine, with high accuracy, the physical and orbital parameters of two double-lined eclipsing binary systems, where the components are two giant stars. We also aim to study the evolutionary status of the binaries, to derive the distances towards them by using a surface brightness-colour relation, and to compare these measurements with the measurements presented by the Gaia mission. In order to measure the physical and orbital parameters of the systems, we analysed the light curves and radial-velocity curves with the Wilson-Devinney code.
