Study of the reflection spectrum of the LMXB 4U 1702-429

Tiziana Di Salvo, Angelo Francesco Gambino, Marco Matranga, Rosario Iaria, Riggio, Pintore, Sanna, Del Santo, Burderi, Papitto

Risultato della ricerca: Article

7 Citazioni (Scopus)

Abstract

Context. The source 4U 1702-429 (Ara X-1) is a low-mass X-ray binary system hosting a neutron star. Albeit the source is quite bright (~1037 erg s-1) its broadband spectrum has never been studied. Neither dips nor eclipses have been observed in the light curve suggesting that its inclination angle is smaller than 60°. Aims. We analysed the broadband spectrum of 4U 1702-429 in the 0.3-60 keV energy range, using XMM-Newton and INTEGRAL data, to constrain its Compton reflection component if it is present. Methods. After excluding the three time intervals in which three type-I X-ray bursts occurred, we fitted the joint XMM-Newton and INTEGRAL spectra obtained from simultaneous observations. Results. A broad emission line at 6.7 keV and two absorption edges at 0.87 and 8.82 keV were detected. We found that a self-consistent reflection model fits the 0.3-60 keV spectrum well. The broadband continuum is composed of an emission component originating from the inner region of the accretion disc, a Comptonised direct emission coming from a corona with an electron temperature of 2.63 ± 0.06 keV and an optical depth τ = 13.6 ± 0.2, and, finally, a reflection component. The best-fit indicates that the broad emission line and the absorption edge at 8.82 keV, both associated with the presence of Fe xxv ions, are produced by reflection in the region above the disc with a ionisation parameter of Log(ξ) 2.7. We have inferred that the inner radius, where the broad emission line originates, is km, and the inner radius of the accretion disc is km. The emissivity of the reflection component and the inclination angle of the system are and degrees, respectively. The absorption edge at 0.87 keV is associated to the presence of O viii ions and it is produced in a region above the disc with Log(ξ) 1.9.
Lingua originaleEnglish
pagine (da-a)A21-
Numero di pagine9
RivistaASTRONOMY & ASTROPHYSICS
Volume596
Stato di pubblicazionePublished - 2016

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XMM-Newton telescope
broadband
accretion disks
newton
inclination
accretion
radii
ion
eclipses
emissivity
erg
optical thickness
optical depth
coronas
neutron stars
light curve
corona
dip
bursts
ions

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cita questo

Study of the reflection spectrum of the LMXB 4U 1702-429. / Di Salvo, Tiziana; Gambino, Angelo Francesco; Matranga, Marco; Iaria, Rosario; Riggio; Pintore; Sanna; Del Santo; Burderi; Papitto.

In: ASTRONOMY & ASTROPHYSICS, Vol. 596, 2016, pag. A21-.

Risultato della ricerca: Article

Di Salvo, T, Gambino, AF, Matranga, M, Iaria, R, Riggio, Pintore, Sanna, Del Santo, Burderi & Papitto 2016, 'Study of the reflection spectrum of the LMXB 4U 1702-429', ASTRONOMY & ASTROPHYSICS, vol. 596, pagg. A21-.
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title = "Study of the reflection spectrum of the LMXB 4U 1702-429",
abstract = "Context. The source 4U 1702-429 (Ara X-1) is a low-mass X-ray binary system hosting a neutron star. Albeit the source is quite bright (~1037 erg s-1) its broadband spectrum has never been studied. Neither dips nor eclipses have been observed in the light curve suggesting that its inclination angle is smaller than 60°. Aims. We analysed the broadband spectrum of 4U 1702-429 in the 0.3-60 keV energy range, using XMM-Newton and INTEGRAL data, to constrain its Compton reflection component if it is present. Methods. After excluding the three time intervals in which three type-I X-ray bursts occurred, we fitted the joint XMM-Newton and INTEGRAL spectra obtained from simultaneous observations. Results. A broad emission line at 6.7 keV and two absorption edges at 0.87 and 8.82 keV were detected. We found that a self-consistent reflection model fits the 0.3-60 keV spectrum well. The broadband continuum is composed of an emission component originating from the inner region of the accretion disc, a Comptonised direct emission coming from a corona with an electron temperature of 2.63 ± 0.06 keV and an optical depth τ = 13.6 ± 0.2, and, finally, a reflection component. The best-fit indicates that the broad emission line and the absorption edge at 8.82 keV, both associated with the presence of Fe xxv ions, are produced by reflection in the region above the disc with a ionisation parameter of Log(ξ) 2.7. We have inferred that the inner radius, where the broad emission line originates, is km, and the inner radius of the accretion disc is km. The emissivity of the reflection component and the inclination angle of the system are and degrees, respectively. The absorption edge at 0.87 keV is associated to the presence of O viii ions and it is produced in a region above the disc with Log(ξ) 1.9.",
keywords = "Accretion, accretion disks; Stars: individual: 4U 1702-429; Stars: neutron; X-rays: binaries; Astronomy and Astrophysics; Space and Planetary Science",
author = "{Di Salvo}, Tiziana and Gambino, {Angelo Francesco} and Marco Matranga and Rosario Iaria and Riggio and Pintore and Sanna and {Del Santo} and Burderi and Papitto",
year = "2016",
language = "English",
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TY - JOUR

T1 - Study of the reflection spectrum of the LMXB 4U 1702-429

AU - Di Salvo, Tiziana

AU - Gambino, Angelo Francesco

AU - Matranga, Marco

AU - Iaria, Rosario

AU - Riggio, null

AU - Pintore, null

AU - Sanna, null

AU - Del Santo, null

AU - Burderi, null

AU - Papitto, null

PY - 2016

Y1 - 2016

N2 - Context. The source 4U 1702-429 (Ara X-1) is a low-mass X-ray binary system hosting a neutron star. Albeit the source is quite bright (~1037 erg s-1) its broadband spectrum has never been studied. Neither dips nor eclipses have been observed in the light curve suggesting that its inclination angle is smaller than 60°. Aims. We analysed the broadband spectrum of 4U 1702-429 in the 0.3-60 keV energy range, using XMM-Newton and INTEGRAL data, to constrain its Compton reflection component if it is present. Methods. After excluding the three time intervals in which three type-I X-ray bursts occurred, we fitted the joint XMM-Newton and INTEGRAL spectra obtained from simultaneous observations. Results. A broad emission line at 6.7 keV and two absorption edges at 0.87 and 8.82 keV were detected. We found that a self-consistent reflection model fits the 0.3-60 keV spectrum well. The broadband continuum is composed of an emission component originating from the inner region of the accretion disc, a Comptonised direct emission coming from a corona with an electron temperature of 2.63 ± 0.06 keV and an optical depth τ = 13.6 ± 0.2, and, finally, a reflection component. The best-fit indicates that the broad emission line and the absorption edge at 8.82 keV, both associated with the presence of Fe xxv ions, are produced by reflection in the region above the disc with a ionisation parameter of Log(ξ) 2.7. We have inferred that the inner radius, where the broad emission line originates, is km, and the inner radius of the accretion disc is km. The emissivity of the reflection component and the inclination angle of the system are and degrees, respectively. The absorption edge at 0.87 keV is associated to the presence of O viii ions and it is produced in a region above the disc with Log(ξ) 1.9.

AB - Context. The source 4U 1702-429 (Ara X-1) is a low-mass X-ray binary system hosting a neutron star. Albeit the source is quite bright (~1037 erg s-1) its broadband spectrum has never been studied. Neither dips nor eclipses have been observed in the light curve suggesting that its inclination angle is smaller than 60°. Aims. We analysed the broadband spectrum of 4U 1702-429 in the 0.3-60 keV energy range, using XMM-Newton and INTEGRAL data, to constrain its Compton reflection component if it is present. Methods. After excluding the three time intervals in which three type-I X-ray bursts occurred, we fitted the joint XMM-Newton and INTEGRAL spectra obtained from simultaneous observations. Results. A broad emission line at 6.7 keV and two absorption edges at 0.87 and 8.82 keV were detected. We found that a self-consistent reflection model fits the 0.3-60 keV spectrum well. The broadband continuum is composed of an emission component originating from the inner region of the accretion disc, a Comptonised direct emission coming from a corona with an electron temperature of 2.63 ± 0.06 keV and an optical depth τ = 13.6 ± 0.2, and, finally, a reflection component. The best-fit indicates that the broad emission line and the absorption edge at 8.82 keV, both associated with the presence of Fe xxv ions, are produced by reflection in the region above the disc with a ionisation parameter of Log(ξ) 2.7. We have inferred that the inner radius, where the broad emission line originates, is km, and the inner radius of the accretion disc is km. The emissivity of the reflection component and the inclination angle of the system are and degrees, respectively. The absorption edge at 0.87 keV is associated to the presence of O viii ions and it is produced in a region above the disc with Log(ξ) 1.9.

KW - Accretion

KW - accretion disks; Stars: individual: 4U 1702-429; Stars: neutron; X-rays: binaries; Astronomy and Astrophysics; Space and Planetary Science

UR - http://hdl.handle.net/10447/227904

UR - http://www.edpsciences.org/journal/index.cfm?edpsname=aa

M3 - Article

VL - 596

SP - A21-

JO - ASTRONOMY & ASTROPHYSICS

JF - ASTRONOMY & ASTROPHYSICS

SN - 0004-6361

ER -