Search Publications
Catalog of X-Ray Detected Be Stars (XDBS)
Kargaltsev, Oleg; Yang, Hui; Hare, Jeremy +2 more
We present a catalog of X-ray Detected Be Stars (XDBS) with 161 Be stars from the Be Star Spectra (BeSS) database having X-ray counterparts in the Chandra Source Catalog v2.0, XMM-Newton 4XMM-DR11 Catalog, or Swift 2SXPS Catalog. The multi-wavelength catalog includes accurate optical positions, X-ray properties (fluxes, photon indices and hardness…
Line Profile Studies of Coronal Active Regions in Fe XII λ195.12 Using Hinode/EIS
Raju, K. P.; Prabhakar, Maya
Coronal active regions are studied using Hinode/EIS observations in the EUV line Fe XII λ195.12 by analyzing their line profiles from 2006 December to 2019 December. The period covers the last 2 yr of solar cycle 23 and solar cycle 24 fully. Active regions are the main source of magnetic field in the solar atmosphere, important in its heating and …
Simulated SPHEREx spectra of asteroids and their implications for asteroid size and reflectance estimation
Doré, Olivier; Ivezić, Željko; Ivezić, Vedrana +6 more
We describe the construction and analysis of simulated SPHEREx spectra of Main Belt and Trojan asteroids. SPHEREx will deliver the first all-sky spectral survey at 96 spectral channels between 0.75 µm and 5.0 µm. We have developed a method for correcting SPHEREx asteroid spectra for intrinsic rotational variability that does not requir…
Analyzing Dominant 13.5 and 27 day Periods of Solar Terrestrial Interaction: A New Insight into Solar Cycle Activities
Saikia, Eeshankur; Syiemlieh, Rissnalin; Adhikary, Manashee +1 more
Our analysis presents an explanation of the Sun-Earth coupling mechanism during declining phase of a solar cycle, and how the dominant 13.5 and 27 day periods play roles in the coupling mechanism which led to intense terrestrial magnetic storms during this declining phase compared to the rising phase of a solar cycle. Moreover, it is observed that…
Insight-HXMT measurements of the diffuse X-ray background
Zhang, J.; Cui, W.; Zhang, S. +8 more
We present an X-ray spectrum of the diffuse X-ray background (DXRB) between 1.5 and 120 keV, as measured with the Low-Energy Detector (LE) and the High-Energy Detector (HE) aboard the Insight-HXMT satellite, based on 'blank-sky' observations. LE covers a nominal energy range of 1-15 keV and HE 20-250 keV, but calibration issues and data quality na…
Reconstructing AGN X-ray spectral parameter distributions with Bayesian methods. I. Spectral analysis
Paltani, Stéphane; Eckert, Dominique; Ge, Lingsong
X-ray spectra of active galactic nuclei (AGN) consist of several different emission and absorption components. To determine the spectral parameters, these components are often fitted manually with models chosen on a case-by-case basis. However, this approach has two problems. First, it becomes very hard for a survey with a large number of sources.…
A possible large-scale alignment of galaxy spin directions - Analysis of 10 datasets from SDSS, Pan-STARRS, and HST
Shamir, Lior
Multiple observations made by several different telescopes have shown asymmetry between the number of spiral galaxies rotating in opposite directions in different parts of the sky. One of the immediate questions regarding the possible asymmetry of the spin directions is whether the distribution forms a cosmological-scale axis. This paper analyzes …
Extreme X-Ray Reflection in the Nucleus of the Seyfert Galaxy NGC 5033
Stern, D.; Brandt, W. N.; Fabian, A. C. +7 more
NGC 5033 is an intriguing Seyfert galaxy because its subclassification may change with time, and because optical and submillimeter observations find that the massive black hole does not sit at the dynamical center of the galaxy, pointing to a past merger. We obtained a new optical spectrum of NGC 5033 using the 200″ Hale telescope at Palomar that …
Milliarcsecond X-Ray Astrometry to Resolve Inner Regions of AGN at z > 1 Using Gravitational Lensing
Barnacka, Anna; Spingola, Cristiana; Schwartz, Daniel
We report the localization of the X-ray emission from two strongly lensed AGN, CLASS B0712+472 (z = 1.34) and CLASS B1608+656 (z = 1.394). We obtain milliarcsecond X-ray astrometry by developing a novel method that combines parametric lens modeling with a Bayesian analysis. We spatially locate the X-ray sources in CLASS B0712+472 and CLASS B1608+6…
FAST Search for Circumstellar Atomic Hydrogen. I. The Young Planetary Nebula IC 4997
Zhang, Yong; Zhang, Chuan-Peng; Parker, Quentin A. +3 more
Using the Five-hundred-meter Aperture Spherical radio Telescope in Guizhou, China, we detect the 21 cm neutral atomic hydrogen absorption in the young planetary nebula IC 4997. The absorption arises from a shell that is also associated with Na I D lines. The H I shell has a mass of 1.46 × 10-2 M ⊙ and a dynamic age of 990 yr.…