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Title: WAVELENGTH MEASUREMENTS OF K TRANSITIONS OF OXYGEN, NEON, AND MAGNESIUM WITH X-RAY ABSORPTION LINES

Accurate atomic transition data are important in many astronomical research areas, especially for studies of line spectroscopy. Whereas transition data of He-like and H-like ions (i.e., ions in high-charge states) have been accurately calculated, the corresponding data of K transitions of neutral or low-ionized metal elements are still very uncertain. Spectroscopy of absorption lines produced in the interstellar medium (ISM) has been proven to be an effective way to measure the central wavelengths of these atomic transitions. In this work, we analyze 36 Chandra High Energy Transmission Grating observations to search for and measure the ISM absorption lines along sight lines to 11 low-mass X-ray binaries. We correct the Galactic rotation velocity to the rest frame for every observation and then use two different methods to merge all the corrected spectra to a co-added spectrum. However, the co-added spectra obtained by this method exhibit biases, toward to either observations with high counts or lines with high signal-to-noise ratios. We do a Bayesian analysis of several significantly detected lines to obtain the systematic uncertainty and the bias correction for other lines. Compared to previous studies, our results improve the wavelength accuracy by a factor of two to five and significantly reducemore » the systematic uncertainties and biases. Several weak transitions (e.g., 1s-2p of Mg IV and Mg V; 1s-3p of Mg III and Mg V) are also detected for the first time, albeit with low significance; future observations with improved accuracy are required to confirm these detections.« less
Authors:
;  [1] ;  [2]
  1. Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)
  2. Eureka Scientific, 2452 Delmer Street Suite 100, Oakland, CA 94602 (United States)
Publication Date:
OSTI Identifier:
22133893
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 774; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; CHARGE STATES; DATA ANALYSIS; MAGNESIUM; MEASURING METHODS; NEON; OXYGEN; SIGNAL-TO-NOISE RATIO; SPECTROSCOPY; VELOCITY; WAVELENGTHS; X RADIATION