Cas A: The bright x-ray knots and oxygen emission

D. Dewey; T. DeLaney; J. S. Lazendic

Cas A: The bright x-ray knots and oxygen emission

D. Dewey, T. DeLaney, J. S. Lazendic

School of Physics and Astronomy

Research output: Chapter in Book/Report/Conference proceeding › Conference Paper › Research › peer-review

5 Citations (Scopus)

Abstract

Chandra High-Energy Transmission Grating (HETG) X-ray spectra are extracted from 17 bright, narrow regions of Cas A and provide unique measurements of their kinematic and plasma states. From the dominant emission lines, e.g. He-like Si, we derive accurate Doppler shifts in the range -2500 to +4000 kms^-1; these agree well with transverse-velocity measurements and allow the features to be located in 3D. Plasma diagnostics of these regions indicate temperatures largely around 1 keV with some above 3 keV. Using as well the non-dispersed zeroth-order data, we determine NEI model parameters for the regions which lead to density estimates. Values of n_e ≈ 100 cm^-3 are likely the maximum of a range of densities in this X-ray emitting material. The common "oxygen-rich" assumption is coarsely tested by comparing the integrated O VIII line flux and continuum levels. It appears that most of the continuum is due to another source, e.g.. from He.

Original language	English
Title of host publication	Circumstellar media and latetsages of massive stellar evolution
Pages	84-89
Number of pages	6
Volume	30
Publication status	Published - 1 Dec 2007
Event	Circumstellar media and late stages of massive stellar evolution - Ensenada, B.C., Mexico Duration: 4 Sep 2006 → 8 Sep 2006

Conference

Conference	Circumstellar media and late stages of massive stellar evolution
Country	Mexico
City	Ensenada, B.C.
Period	4/09/06 → 8/09/06

Keywords

Radiation mechanisms: Thermal
Supernova remnants: Individual(Cas A, G111.7-2.1)
Techniques: Spectroscopic
X-Rays: ISM

Access to Document

Link to publication in Scopus

Cite this

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title = "Cas A: The bright x-ray knots and oxygen emission",

abstract = "Chandra High-Energy Transmission Grating (HETG) X-ray spectra are extracted from 17 bright, narrow regions of Cas A and provide unique measurements of their kinematic and plasma states. From the dominant emission lines, e.g. He-like Si, we derive accurate Doppler shifts in the range -2500 to +4000 kms-1; these agree well with transverse-velocity measurements and allow the features to be located in 3D. Plasma diagnostics of these regions indicate temperatures largely around 1 keV with some above 3 keV. Using as well the non-dispersed zeroth-order data, we determine NEI model parameters for the regions which lead to density estimates. Values of ne ≈ 100 cm-3 are likely the maximum of a range of densities in this X-ray emitting material. The common {"}oxygen-rich{"} assumption is coarsely tested by comparing the integrated O VIII line flux and continuum levels. It appears that most of the continuum is due to another source, e.g.. from He.",

keywords = "Radiation mechanisms: Thermal, Supernova remnants: Individual(Cas A, G111.7-2.1), Techniques: Spectroscopic, X-Rays: ISM",

author = "D. Dewey and T. DeLaney and Lazendic, {J. S.}",

year = "2007",

month = dec,

day = "1",

language = "English",

isbn = "9789703232758",

volume = "30",

pages = "84--89",

booktitle = "Circumstellar media and latetsages of massive stellar evolution",

note = "Circumstellar media and late stages of massive stellar evolution ; Conference date: 04-09-2006 Through 08-09-2006",

}

TY - GEN

T1 - Cas A

T2 - Circumstellar media and late stages of massive stellar evolution

AU - Dewey, D.

AU - DeLaney, T.

AU - Lazendic, J. S.

PY - 2007/12/1

Y1 - 2007/12/1

N2 - Chandra High-Energy Transmission Grating (HETG) X-ray spectra are extracted from 17 bright, narrow regions of Cas A and provide unique measurements of their kinematic and plasma states. From the dominant emission lines, e.g. He-like Si, we derive accurate Doppler shifts in the range -2500 to +4000 kms-1; these agree well with transverse-velocity measurements and allow the features to be located in 3D. Plasma diagnostics of these regions indicate temperatures largely around 1 keV with some above 3 keV. Using as well the non-dispersed zeroth-order data, we determine NEI model parameters for the regions which lead to density estimates. Values of ne ≈ 100 cm-3 are likely the maximum of a range of densities in this X-ray emitting material. The common "oxygen-rich" assumption is coarsely tested by comparing the integrated O VIII line flux and continuum levels. It appears that most of the continuum is due to another source, e.g.. from He.

AB - Chandra High-Energy Transmission Grating (HETG) X-ray spectra are extracted from 17 bright, narrow regions of Cas A and provide unique measurements of their kinematic and plasma states. From the dominant emission lines, e.g. He-like Si, we derive accurate Doppler shifts in the range -2500 to +4000 kms-1; these agree well with transverse-velocity measurements and allow the features to be located in 3D. Plasma diagnostics of these regions indicate temperatures largely around 1 keV with some above 3 keV. Using as well the non-dispersed zeroth-order data, we determine NEI model parameters for the regions which lead to density estimates. Values of ne ≈ 100 cm-3 are likely the maximum of a range of densities in this X-ray emitting material. The common "oxygen-rich" assumption is coarsely tested by comparing the integrated O VIII line flux and continuum levels. It appears that most of the continuum is due to another source, e.g.. from He.

KW - Radiation mechanisms: Thermal

KW - Supernova remnants: Individual(Cas A, G111.7-2.1)

KW - Techniques: Spectroscopic

KW - X-Rays: ISM

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M3 - Conference Paper

AN - SCOPUS:38349097836

SN - 9789703232758

VL - 30

SP - 84

EP - 89

BT - Circumstellar media and latetsages of massive stellar evolution

Y2 - 4 September 2006 through 8 September 2006

ER -