Search Publications
X-Ray Intraday Variability of the TeV Blazar Markarian 421 with XMM-Newton
Gupta, Alok C.; Gaur, Haritma; Ostrowski, Michał +4 more
Highly variable Markarian 421 is a bright high-synchrotron energy peaked blazar showing a wide featureless nonthermal spectrum, making it a good candidate for our study of intraday flux and spectral variations over time. We analyze its X-ray observations over 17 yr, taken with the EPIC-pn instrument, to probe into the intraday variability properti…
Statistical Analysis of Circular-ribbon Flares
Xu, Zhe; Li, Shuting; Zhang, Qingmin +4 more
Circular-ribbon flares (CFs) are a special type of solar flares owing to their particular magnetic topology. In this paper, we conducted a comprehensive statistical analysis of 134 CFs from 2011 September to 2017 June, including 4 B-class, 82 C-class, 40 M-class, and 8 X-class flares. The flares were observed by the Atmospheric Imaging Assembly on…
Chemical Composition of Bright Stars in the Northern Hemisphere: Star-Planet Connection
Grundahl, F.; Kjeldsen, H.; von Essen, C. +12 more
In fulfilling the aims of the planetary and asteroseismic research missions, such as that of the NASA Transiting Exoplanet Survey Satellite (TESS) space telescope, accurate stellar atmospheric parameters and a detailed chemical composition are required as inputs. We have observed high-resolution spectra for all 848 bright (V < 8 mag) stars that…
Mass and Age Determination of the LAMOST Data with Different Machine-learning Methods
Ting, Yuan-Sen; Deng, Li-Cai; Wang, Hai-Feng +3 more
We present a catalog of 948,216 stars with mass labels and a catalog of 163,105 red clump (RC) stars with mass and age labels simultaneously. The training data set is crossmatched from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope DR5, and high-resolution asteroseismology data, mass, and age are predicted by the random forest (RF) …
Kepler Pixel Project: Background RR Lyrae Stars in the Primary Kepler Mission Field of View
Bódi, Attila; Szabó, Róbert; Forró, Adrienn +1 more
In this paper, we describe a project we initiated to investigate individual pixels in downloaded Kepler apertures in order to find objects in the background of the main targets with variable brightness. In the first paper of this series, we discovered and investigated 547 short-period eclipsing binaries. Here we present the independent discovery o…
Stellar Loci. VI. An Updated Catalog of the Best and Brightest Metal-poor Stars
Huang, Yang; Beers, Timothy C.; Li, Haining +3 more
We employ Gaia, Two Micron All Sky Survey, and ALLWISE photometry, as well as astrometric data from Gaia, to search for relatively bright very metal-poor (VMP; [Fe/H] < -2.0) giant star candidates using three different criteria: (1) the derived Gaia photometric metallicities from Xu et al., (2) the lack of stellar molecular absorption near 4.6 …
In the Trenches of the Solar-Stellar Connection. VI. Total EclipSS
Buzasi, Derek; Ayres, Thomas
The Ecliptic poles Stellar Survey (EclipSS; 2018-2019) collected Hubble Space Telescope/Cosmic Origins Spectrograph (COS) 1150-1420 Å spectra of 49 FGK dwarfs at high ecliptic latitudes. These regions are favored by the scanning programs of the Transiting Exoplanet Survey Satellite (TESS; high-precision optical light curves) and Extended Roentgen …
Molecules in the Carbon-rich Protoplanetary Nebula CRL 2688
Zhang, Yong; Zhang, Jiang-Shui; Nakashima, Jun-ichi +1 more
We present observations of the carbon-rich protoplanetary nebula CRL 2688 made with the Institut de Radioastronomie Millimétrique 30 m telescope in the 3 and 2 mm bands. In total, 196 transition lines belonging to 38 molecular species and isotopologues are detected, among which, to the best of our knowledge, 153 transition lines and 13 species are…
H-band Light Curves of Milky Way Cepheids via Difference Imaging
Jones, David O.; Riess, Adam G.; Yuan, Wenlong +4 more
We present H-band light curves of Milky Way classical Cepheids observed as part of the Dark Energy, H 0, and peculiar Velocities using Infrared Light from Supernovae survey with the Wide-Field Infrared Camera on the United Kingdom Infrared Telescope. Due to the crowded nature of these fields caused by defocusing the Camera, we performed…
Robust Inference of Neutron-star Parameters from Thermonuclear Burst Observations
Galloway, Duncan K.; Goodwin, Adelle; Johnston, Zac +1 more
Thermonuclear (type-I) bursts arise from unstable ignition of accumulated fuel on the surface of neutron stars in low-mass X-ray binaries. Measurements of burst properties in principle enable observers to infer the properties of the host neutron star and mass donors, but a number of confounding astrophysical effects contribute to systematic uncert…