skip to main content

SciTech ConnectSciTech Connect

Title: SPECTROSCOPIC STUDIES OF AN ULTRALUMINOUS SUPERSOFT X-RAY SOURCE IN M81

Ultraluminous supersoft X-ray sources (ULSs) exhibit supersoft X-ray spectra with blackbody temperatures below 0.1 keV and bolometric luminosities above 10{sup 39} ergs s{sup −1}. In this Letter, we report the first optical spectroscopic observations of a ULS in M81 using the LRIS spectrograph on the Keck I telescope. The detected Balmer emission lines show a mean intrinsic velocity dispersion of 400 ± 80 km s{sup −1}, which is consistent with that from an accretion disk. The spectral index of the continuum on the blue side is also consistent with the multi-color disk model. The H{sub α} emission line exhibits a velocity of ∼180 km s{sup −1} relative to the local stellar environment, suggesting that this ULS may be a halo system in M81 belonging to an old population. No significant shift is found for the H{sub α} emission line between two observations separated by four nights.
Authors:
; ;  [1]
  1. Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, 20 A Datun Road, Chaoyang Distict, 100012 Beijing (China)
Publication Date:
OSTI Identifier:
22518834
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 802; 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; ACCRETION DISKS; BOLOMETERS; COLOR; COSMIC X-RAY SOURCES; EMISSION SPECTROSCOPY; GALAXIES; KEV RANGE; LUMINOSITY; TELESCOPES; VELOCITY; X-RAY SPECTRA