On the soft excess in the x-ray spectrum of circinus X-1: Revisitation of the distance to circinus X-1

Tiziana Di Salvo, Rosario Iaria, Van Der Klis, Burderi, Fender, Frontera, Luciano Burderi, Marco Spano'

Risultato della ricerca: Article

23 Citazioni (Scopus)

Abstract

We report on a 300 ks BeppoSAX(0.12-200 keV) observation of Circinus X-1 (CirX-1) at phases between 0.62 and 0.84 and on a 90 ks BeppoSAX observation of Cir X-1 at phases 0.11 -0.16. Using the canonical model adopted until now to fit the energy spectrum of this source, large residuals appear below 1 keV. These are well fitted using an equivalent hydrogen column of 0.66 × 1022 cm-2, adding absorption edges of 0 VII, 0 VIII, and Ne ix in the spectra extracted from the observation at phases 0.62-0.84 and adding absorption edges of 0 VII, 0 VIII, Mg XI, and Mg XII and absorption lines of 0 VII and Mg XII in the spectra extracted from the observation at phases 0.11-0.16. During the observation at phases 0.62-0.84 the electron density associated with the ionized matter is -1013 cm-3, remaining quite constant going away from the compact object. During the observation at phases 0.11-0.16, the electron density profile varies along the distance going from ∼6 × 1013 cm-3 at ∼1011 cm to ∼9 × 1010 cm-3 at ∼1013 cm. The equivalent hydrogen column toward Cir X-1 is 3 times lower than the value obtained from previous models. This low value would imply that Cir X-1 is at a distance of 4.1 kpc.
Lingua originaleEnglish
pagine (da-a)503-516
Numero di pagine14
RivistaDefault journal
Volume619
Stato di pubblicazionePublished - 2005

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x ray spectra
electron density
hydrogen
electron density profiles
energy
energy spectra

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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On the soft excess in the x-ray spectrum of circinus X-1: Revisitation of the distance to circinus X-1. / Di Salvo, Tiziana; Iaria, Rosario; Van Der Klis; Burderi; Fender; Frontera; Burderi, Luciano; Spano', Marco.

In: Default journal, Vol. 619, 2005, pag. 503-516.

Risultato della ricerca: Article

Di Salvo, T, Iaria, R, Van Der Klis, Burderi, Fender, Frontera, Burderi, L & Spano', M 2005, 'On the soft excess in the x-ray spectrum of circinus X-1: Revisitation of the distance to circinus X-1', Default journal, vol. 619, pagg. 503-516.
Di Salvo, Tiziana ; Iaria, Rosario ; Van Der Klis ; Burderi ; Fender ; Frontera ; Burderi, Luciano ; Spano', Marco. / On the soft excess in the x-ray spectrum of circinus X-1: Revisitation of the distance to circinus X-1. In: Default journal. 2005 ; Vol. 619. pagg. 503-516.
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title = "On the soft excess in the x-ray spectrum of circinus X-1: Revisitation of the distance to circinus X-1",
abstract = "We report on a 300 ks BeppoSAX(0.12-200 keV) observation of Circinus X-1 (CirX-1) at phases between 0.62 and 0.84 and on a 90 ks BeppoSAX observation of Cir X-1 at phases 0.11 -0.16. Using the canonical model adopted until now to fit the energy spectrum of this source, large residuals appear below 1 keV. These are well fitted using an equivalent hydrogen column of 0.66 × 1022 cm-2, adding absorption edges of 0 VII, 0 VIII, and Ne ix in the spectra extracted from the observation at phases 0.62-0.84 and adding absorption edges of 0 VII, 0 VIII, Mg XI, and Mg XII and absorption lines of 0 VII and Mg XII in the spectra extracted from the observation at phases 0.11-0.16. During the observation at phases 0.62-0.84 the electron density associated with the ionized matter is -1013 cm-3, remaining quite constant going away from the compact object. During the observation at phases 0.11-0.16, the electron density profile varies along the distance going from ∼6 × 1013 cm-3 at ∼1011 cm to ∼9 × 1010 cm-3 at ∼1013 cm. The equivalent hydrogen column toward Cir X-1 is 3 times lower than the value obtained from previous models. This low value would imply that Cir X-1 is at a distance of 4.1 kpc.",
author = "{Di Salvo}, Tiziana and Rosario Iaria and {Van Der Klis} and Burderi and Fender and Frontera and Luciano Burderi and Marco Spano'",
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T1 - On the soft excess in the x-ray spectrum of circinus X-1: Revisitation of the distance to circinus X-1

AU - Di Salvo, Tiziana

AU - Iaria, Rosario

AU - Van Der Klis, null

AU - Burderi, null

AU - Fender, null

AU - Frontera, null

AU - Burderi, Luciano

AU - Spano', Marco

PY - 2005

Y1 - 2005

N2 - We report on a 300 ks BeppoSAX(0.12-200 keV) observation of Circinus X-1 (CirX-1) at phases between 0.62 and 0.84 and on a 90 ks BeppoSAX observation of Cir X-1 at phases 0.11 -0.16. Using the canonical model adopted until now to fit the energy spectrum of this source, large residuals appear below 1 keV. These are well fitted using an equivalent hydrogen column of 0.66 × 1022 cm-2, adding absorption edges of 0 VII, 0 VIII, and Ne ix in the spectra extracted from the observation at phases 0.62-0.84 and adding absorption edges of 0 VII, 0 VIII, Mg XI, and Mg XII and absorption lines of 0 VII and Mg XII in the spectra extracted from the observation at phases 0.11-0.16. During the observation at phases 0.62-0.84 the electron density associated with the ionized matter is -1013 cm-3, remaining quite constant going away from the compact object. During the observation at phases 0.11-0.16, the electron density profile varies along the distance going from ∼6 × 1013 cm-3 at ∼1011 cm to ∼9 × 1010 cm-3 at ∼1013 cm. The equivalent hydrogen column toward Cir X-1 is 3 times lower than the value obtained from previous models. This low value would imply that Cir X-1 is at a distance of 4.1 kpc.

AB - We report on a 300 ks BeppoSAX(0.12-200 keV) observation of Circinus X-1 (CirX-1) at phases between 0.62 and 0.84 and on a 90 ks BeppoSAX observation of Cir X-1 at phases 0.11 -0.16. Using the canonical model adopted until now to fit the energy spectrum of this source, large residuals appear below 1 keV. These are well fitted using an equivalent hydrogen column of 0.66 × 1022 cm-2, adding absorption edges of 0 VII, 0 VIII, and Ne ix in the spectra extracted from the observation at phases 0.62-0.84 and adding absorption edges of 0 VII, 0 VIII, Mg XI, and Mg XII and absorption lines of 0 VII and Mg XII in the spectra extracted from the observation at phases 0.11-0.16. During the observation at phases 0.62-0.84 the electron density associated with the ionized matter is -1013 cm-3, remaining quite constant going away from the compact object. During the observation at phases 0.11-0.16, the electron density profile varies along the distance going from ∼6 × 1013 cm-3 at ∼1011 cm to ∼9 × 1010 cm-3 at ∼1013 cm. The equivalent hydrogen column toward Cir X-1 is 3 times lower than the value obtained from previous models. This low value would imply that Cir X-1 is at a distance of 4.1 kpc.

UR - http://hdl.handle.net/10447/228738

UR - http://iopscience.iop.org/0004-637X/

M3 - Article

VL - 619

SP - 503

EP - 516

JO - Default journal

JF - Default journal

ER -