Search Publications
An Image-based Search for Pulsar Candidates in the MeerKAT Bulge Survey
Calore, Francesca; Kaplan, David L.; Clavel, Maïca +13 more
We report on the results of an image-based search for pulsar candidates toward the Galactic bulge. We used mosaic images from the MeerKAT radio telescope that were taken as part of a 173 deg2 survey of the bulge and Galactic center of our Galaxy at L band (856–1712 MHz) in all four Stokes I, Q, U, and V. The image rms noise levels of 12…
Calibration of metallicity of LAMOST M dwarf stars using FGK+M wide binaries
Tian, Haijun; Qiu, Dan; Niu, Zexi +3 more
Estimating precise metallicity of M dwarfs is a well-known difficult problem due to their complex spectra. In this work, we empirically calibrate the metallicity using wide binaries with a F, G, or K dwarf and a M dwarf companion. With 1308 FGK+M wide binaries well observed by LAMOST, we calibrated M dwarf's [Fe/H] by using the Stellar LAbel Machi…
Geometry of the LMC based on multiphase analysis of multiwavelength Cepheid light curves using OGLE-IV and Gaia DR3 data
Deb, Sukanta; Kanbur, Shashi M.; Bhardwaj, Anupam +3 more
The period-luminosity (PL) relation of Cepheids in the Large Magellanic Cloud (LMC) plays a pivotal role in extragalactic distance measurement and the determination of the Hubble constant (H0). In this work, we probe the geometry of the LMC through a detailed study of multiphase PL relations of these Cepheids, leveraging data from the O…
Stellar Atmospheric Parameters of ∼11,000 RR Lyrae Stars from LAMOST Spectra
Shi, Jianrong; Zong, Weikai; Wang, Jiangtao +2 more
Accurate determination of the stellar atmospheric parameters of RR Lyrae stars (RRLs) requires short individual exposures of the spectra to mitigate pulsation effects. We present improved template-matching methods to determine the stellar atmospheric parameters of RRLs from single-epoch spectra of the Large Sky Area Multi-Object Fiber Spectroscopi…
Deep investigation of a pair of open clusters NGC 7031 and NGC 7086 utilizing Gaia DR3
Elsanhoury, W. H.; Haroon, A. A.; Elkholy, E. A. +1 more
In this paper, we carried out photometric and kinematic study of two poorly studied open clusters NGC 7031 and NGC 7086 utilizing the optical wavelength of Gaia DR3. We identified 613 and 226 candidates for respective clusters as highly probable astrometric members. Fitting King's profile within RDPs, we estimate both core and limiting radii. For …
Doppler imaging of a southern ApSi star HD 152564
Potravnov, I.; Ryabchikova, T.; Piskunov, N. +2 more
We present the results of the spectroscopic study of a chemically peculiar star HD 152564. Using medium-resolution (R = 37 000) observations obtained with the high-resolution fibre échelle spectrograph mounted on the South African Large Telescope, we determined atmospheric parameters Teff = 11 950 ± 200 K and log g = 3.6 ± 0.2 dex. Abun…
Validation of Gaia DR3 Orbital and Acceleration Solutions with Hierarchical Triples
El-Badry, Kareem; Nagarajan, Pranav
Using data from Gaia DR3, we construct a sample of 14,791 gravitationally bound wide pairs in which one of the components is an unresolved binary with an astrometric orbital or acceleration solution. These systems are hierarchical triples, with inner binary separations of order 1 au, and outer separations of 100–100,000 au. Leveraging the fact tha…
Observational Evidence for Hot Wind Impact on Parsec Scales in Low-luminosity Active Galactic Nuclei
Li, Zhiyuan; Shi, Fangzheng; Yuan, Feng +2 more
Supermassive black holes in galaxies spend the majority of their lifetime in the low-luminosity regime, powered by hot accretion flow. Strong winds launched from the hot accretion flow have the potential to play an important role in active galactic nuclei (AGN) feedback. Direct observational evidence for these hot winds with temperatures around 10…
The Magellanic Clouds Are Very Rare in the IllustrisTNG Simulations
Kroupa, Pavel; Haslbauer, Moritz; Banik, Indranil +2 more
The Large and Small Magellanic Clouds (LMC and SMC) form the closest interacting galactic system to the Milky Way, therewith providing a laboratory to test cosmological models in the local Universe. We quantify the likelihood for the Magellanic Clouds (MCs) to be observed within the
Updated Spectral Characteristics for the Ultracool Dwarf TRAPPIST-1
Burgasser, Adam J.; Davoudi, Fatemeh; Rackham, Benjamin V. +5 more
A comprehensive infrared spectroscopic study of star TRAPPIST-1 is a crucial step toward the detailed examination of its planets. While the presence of Earth's atmosphere has limited the spectral extent of such a study up to now, the Near Infrared Imager and Slitless Spectrograph (NIRISS) and the Near Infrared Spectrograph instruments aboard the J…