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Title: OBSERVATION OF THE FAR-ULTRAVIOLET CONTINUUM BACKGROUND WITH SPEAR/FIMS

Abstract

We present the general properties of the far-ultraviolet (FUV; 1370-1710 A) continuum background over most of the sky, obtained with the Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR) instrument (also known as FIMS), flown aboard the STSAT-1 satellite mission. We find that the diffuse FUV continuum intensity is well correlated with N{sub HI}, 100 {mu}m, and H{alpha} intensities but anti-correlated with soft X-ray intensity. The correlation of the diffuse background with the direct stellar flux is weaker than the correlation with other parameters. The continuum spectra are relatively flat. However, a weak softening of the FUV spectra toward some sight lines, mostly at high Galactic latitudes, is found not only in direct stellar but also in diffuse background spectra. The diffuse background is relatively softer than the direct stellar spectrum. We also find that the diffuse FUV background averaged over the sky has a bit softer spectrum compared to direct stellar radiation. A map of the ratio of 1370-1520 A to 1560-1710 A band intensity shows that the sky is divided into roughly two parts. However, this map shows a lot of patchy structures on small scales. The spatial variation of the hardness ratio seems to be largely determinedmore » by the longitudinal distribution of OB-type stars in the Galactic plane. A correlation of the hardness ratio with the FUV intensity is found at high intensities but an anti-correlation is found at low intensities. We also find evidence that the FUV intensity distribution is log-normal in nature.« less

Authors:
; ; ;  [1]; ;  [2];  [3];  [4];  [5]
  1. Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)
  2. Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)
  3. Ritter Astrophysical Research Center, University of Toledo, Toledo, OH 43606 (United States)
  4. Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)
  5. Korea Intellectual Property Office, Daejeon 302-701 (Korea, Republic of)
Publication Date:
OSTI Identifier:
21560328
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal, Supplement Series
Additional Journal Information:
Journal Volume: 196; Journal Issue: 2; Other Information: DOI: 10.1088/0067-0049/196/2/15; Journal ID: ISSN 0067-0049
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CORRELATIONS; FAR ULTRAVIOLET RADIATION; MAPS; SKY; SOFT X RADIATION; STARS; STELLAR RADIATION; ELECTROMAGNETIC RADIATION; IONIZING RADIATIONS; RADIATIONS; ULTRAVIOLET RADIATION; X RADIATION

Citation Formats

Seon, Kwang-Il, Han, Wonyong, Shinn, Jongho, Kim, Il-Joong, Edelstein, Jerry, Korpela, Eric, Witt, Adolf, Min, Kyoung-Wook, and Park, Jae-Woo, E-mail: kiseon@kasi.re.kr. OBSERVATION OF THE FAR-ULTRAVIOLET CONTINUUM BACKGROUND WITH SPEAR/FIMS. United States: N. p., 2011. Web. doi:10.1088/0067-0049/196/2/15.
Seon, Kwang-Il, Han, Wonyong, Shinn, Jongho, Kim, Il-Joong, Edelstein, Jerry, Korpela, Eric, Witt, Adolf, Min, Kyoung-Wook, & Park, Jae-Woo, E-mail: kiseon@kasi.re.kr. OBSERVATION OF THE FAR-ULTRAVIOLET CONTINUUM BACKGROUND WITH SPEAR/FIMS. United States. doi:10.1088/0067-0049/196/2/15.
Seon, Kwang-Il, Han, Wonyong, Shinn, Jongho, Kim, Il-Joong, Edelstein, Jerry, Korpela, Eric, Witt, Adolf, Min, Kyoung-Wook, and Park, Jae-Woo, E-mail: kiseon@kasi.re.kr. Sat . "OBSERVATION OF THE FAR-ULTRAVIOLET CONTINUUM BACKGROUND WITH SPEAR/FIMS". United States. doi:10.1088/0067-0049/196/2/15.
@article{osti_21560328,
title = {OBSERVATION OF THE FAR-ULTRAVIOLET CONTINUUM BACKGROUND WITH SPEAR/FIMS},
author = {Seon, Kwang-Il and Han, Wonyong and Shinn, Jongho and Kim, Il-Joong and Edelstein, Jerry and Korpela, Eric and Witt, Adolf and Min, Kyoung-Wook and Park, Jae-Woo, E-mail: kiseon@kasi.re.kr},
abstractNote = {We present the general properties of the far-ultraviolet (FUV; 1370-1710 A) continuum background over most of the sky, obtained with the Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR) instrument (also known as FIMS), flown aboard the STSAT-1 satellite mission. We find that the diffuse FUV continuum intensity is well correlated with N{sub HI}, 100 {mu}m, and H{alpha} intensities but anti-correlated with soft X-ray intensity. The correlation of the diffuse background with the direct stellar flux is weaker than the correlation with other parameters. The continuum spectra are relatively flat. However, a weak softening of the FUV spectra toward some sight lines, mostly at high Galactic latitudes, is found not only in direct stellar but also in diffuse background spectra. The diffuse background is relatively softer than the direct stellar spectrum. We also find that the diffuse FUV background averaged over the sky has a bit softer spectrum compared to direct stellar radiation. A map of the ratio of 1370-1520 A to 1560-1710 A band intensity shows that the sky is divided into roughly two parts. However, this map shows a lot of patchy structures on small scales. The spatial variation of the hardness ratio seems to be largely determined by the longitudinal distribution of OB-type stars in the Galactic plane. A correlation of the hardness ratio with the FUV intensity is found at high intensities but an anti-correlation is found at low intensities. We also find evidence that the FUV intensity distribution is log-normal in nature.},
doi = {10.1088/0067-0049/196/2/15},
journal = {Astrophysical Journal, Supplement Series},
issn = {0067-0049},
number = 2,
volume = 196,
place = {United States},
year = {2011},
month = {10}
}