Search Publications
The ALPINE-ALMA [C II] Survey: The Infrared-Radio Correlation and Active Galactic Nucleus Fraction of Star-forming Galaxies at z 4.4-5.9
Shen, Lu; Koekemoer, Anton M.; Jones, Gareth C. +26 more
We present the radio properties of 66 spectroscopically confirmed normal star-forming galaxies (SFGs) at 4.4 < z < 5.9 in the COSMOS field that were [C II]-detected in the Atacama Large Millimeter/submillimeter Array Large Program to INvestigate [C II] at Early times (ALPINE). We separate these galaxies ("C II-detected-all") into lower-redsh…
Spectroscopic Study of Four Metal-poor Carbon Stars from the Hamburg/ESO Survey: On Confirming the Low-mass Nature of Their Companions
Shejeelammal, J.; Goswami, Aruna
Elemental abundances of extrinsic carbon stars provide insight into the poorly understood origin and evolution of elements in the early Galaxy. In this work, we present the results of a detailed spectroscopic analysis of four potential carbon star candidates from the Hamburg/ESO Survey (HES): HE 0457-1805, HE 0920-0506, HE 1241-0337, and HE 1327-2…
Asteroseismology of the DAV Star L19-2
Chen, Yanhui
L19-2 is a DAV star, which was intermittently observed from 1976 to 2013. Five independent pulsation modes of 350, 192, 143, 118, and 113 s are identified. The five modes can be used to constrain the fitting models. The rates of period change can be obtained through the O-C method for the modes of 192 and 113 s, which can be used to study the evol…
A Very Metal-poor RR Lyrae Star with a Disk Orbit Found in the Solar Neighborhood
Kobayashi, Naoto; Maehara, Hiroyuki; Hattori, Kohei +28 more
Metal-deficient stars are important tracers for understanding the early formation of the Galaxy. Recent large-scale surveys with both photometric and spectroscopic data have reported an increasing number of metal-deficient stars whose kinematic features are consistent with those of the disk stellar populations. We report the discovery of an RR Lyr…
White Dwarf Photospheric Abundances in Cataclysmic Variables-II. White Dwarfs with and without a Mask
Sion, Edward M.; Godon, Patrick
Taking advantage of the now-available Gaia EDR3 parallaxes, we carry out an archival Hubble Space Telescope (HST) far-ultraviolet spectroscopic analysis of 10 cataclysmic variable systems, including five carefully selected eclipsing systems. We obtain accurate white dwarf (WD) masses and temperatures, in excellent agreement with the masses for fou…
Homologous Compact Major Blowout-eruption Solar Flares and their Production of Broad CMEs
Joshi, Bhuwan; Moore, Ronald L.; Sterling, Alphonse C. +2 more
We analyze the formation mechanism of three homologous broad coronal mass ejections (CMEs) resulting from a series of solar blowout-eruption flares with successively increasing intensities (M2.0, M2.6, and X1.0). The flares originated from NOAA Active Region 12017 during 2014 March 28-29 within an interval of ≈24 hr. Coronal magnetic field modelin…
Data-driven Derivation of Stellar Properties from Photometric Time Series Data Using Convolutional Neural Networks
Angus, Ruth; Huber, Daniel; Ness, Melissa K. +2 more
Stellar variability is driven by a multitude of internal physical processes that depend on fundamental stellar properties. These properties are our bridge to reconciling stellar observations with stellar physics and to understand the distribution of stellar populations within the context of galaxy formation. Numerous ongoing and upcoming missions …
Investigating the Accretion Nature of Binary Supermassive Black Hole Candidate SDSS J025214.67-002813.7
Shi, Fangzheng; Gültekin, Kayhan; Chen, Yu-Ching +3 more
We present results of a multiwavelength analysis of SDSS J025214.67-002813.7, a system that has been previously classified as a binary active galactic nucleus (AGN) candidate based on periodic signals detected in the optical light curves. We use available radio-X-ray observations of the system to investigate the true accretion nature. Analyzing ne…
Three-dimensional Magnetic and Thermodynamic Structures of Solar Microflares
Cheng, X.; Ding, M. D.; Chen, J. +2 more
Microflares, one of the small-scale solar activities, are believed to be caused by magnetic reconnection. Nevertheless, their three-dimensional (3D) magnetic structures, thermodynamic structures, and physical links to reconnection are unclear. In this Letter, based on a high-resolution 3D radiative magnetohydrodynamic simulation of the quiet Sun s…
Ice Features of Low-luminosity Protostars in Near-infrared Spectra of AKARI/IRC
Choi, Minho; Lee, Jeong-Eun; Dunham, Michael M. +8 more
We present near-infrared spectra of three low-luminosity protostars and one background star in the Perseus molecular cloud, acquired using the infrared camera on board the AKARI space telescope. For the comparison with different star-forming environments, we also present spectra of the massive protostar AFGL 7009S, where the protostellar envelope …