XMM-Newton and INTEGRAL view of the hard state of EXO 1745-248 during its 2015 outburst

Tiziana Di Salvo, Rosario Iaria, Marco Matranga, Angelo Francesco Gambino, De Martino, Burderi, Stella, Papitto, Ferrigno, Bozzo, Rea, Sanchez-Fernandez, Torres

Risultato della ricerca: Article

2 Citazioni (Scopus)

Abstract

Context. Transient low-mass X-ray binaries (LMXBs) often show outbursts that typically last a few weeks and are characterized by a high X-ray luminosity (Lx ≈ 1036-1038 erg s-1), while most of the time they are found in X-ray quiescence (LX ≈ 1031-1033 erg s-1). The source EXO 1745-248 is one of them. Aims. The broad-band coverage and sensitivity of the instrument on board XMM-Newton and INTEGRAL offers the opportunity of characterizing the hard X-ray spectrum during the outburst of EXO 1745-248. Methods. We report on quasi-simultaneous XMM-Newton and INTEGRAL observations of the X-ray transient EXO 1745-248 located in the globular cluster Terzan 5, performed ten days after the beginning of the outburst (on 2015 March 16) of the source between March and June 2015. The source was caught in a hard state, emitting a 0.8-100 keV luminosity of ≃ 1037 erg s-1. Results. The spectral continuum was dominated by thermal Comptonization of seed photons with temperature kTin ≃ 1.3 keV, by a cloud with a moderate optical depth τ ≃ 2, and with an electron temperature of kTe ≃ 40 keV. A weaker soft thermal component at temperature kTth ≃ 0.6-0.7 keV and compatible with a fraction of the neutron star radius was also detected. A rich emission line spectrum was observed by the EPIC-pn on board XMM-Newton; features at energies compatible with K-α transitions of ionized sulfur, argon, calcium, and iron were detected, with a broadness compatible with either thermal Compton broadening or Doppler broadening in the inner parts of an accretion disk truncated at 20 ± 6 gravitational radii from the neutron star. Strikingly, at least one narrow emission line ascribed to neutral or mildly ionized iron is needed to model the prominent emission complex detected between 5.5 and 7.5 keV. The different ionization state and broadness suggest an origin in a region located farther from the neutron star than where the other emission lines are produced. Seven consecutive type I bursts were detected during the XMM-Newton observation, none of which showed hints of photospheric radius expansion. A thorough search for coherent pulsations from the EPIC-pn light curve did not result in any significant detection. Upper limits ranging from a few to 15% on the signal amplitude were set, depending on the unknown spin and orbital parameters of the system.
Lingua originaleEnglish
pagine (da-a)A39-
Numero di pagine13
RivistaASTRONOMY & ASTROPHYSICS
Volume603
Stato di pubblicazionePublished - 2017

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XMM-Newton telescope
outburst
newton
erg
neutron stars
x rays
radii
luminosity
iron
temperature
argon
globular clusters
accretion disks
optical thickness
optical depth
light curve
line spectra
seeds
calcium
bursts

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cita questo

XMM-Newton and INTEGRAL view of the hard state of EXO 1745-248 during its 2015 outburst. / Di Salvo, Tiziana; Iaria, Rosario; Matranga, Marco; Gambino, Angelo Francesco; De Martino; Burderi; Stella; Papitto; Ferrigno; Bozzo; Rea; Sanchez-Fernandez; Torres.

In: ASTRONOMY & ASTROPHYSICS, Vol. 603, 2017, pag. A39-.

Risultato della ricerca: Article

Di Salvo, T, Iaria, R, Matranga, M, Gambino, AF, De Martino, Burderi, Stella, Papitto, Ferrigno, Bozzo, Rea, Sanchez-Fernandez & Torres 2017, 'XMM-Newton and INTEGRAL view of the hard state of EXO 1745-248 during its 2015 outburst', ASTRONOMY & ASTROPHYSICS, vol. 603, pagg. A39-.
Di Salvo, Tiziana ; Iaria, Rosario ; Matranga, Marco ; Gambino, Angelo Francesco ; De Martino ; Burderi ; Stella ; Papitto ; Ferrigno ; Bozzo ; Rea ; Sanchez-Fernandez ; Torres. / XMM-Newton and INTEGRAL view of the hard state of EXO 1745-248 during its 2015 outburst. In: ASTRONOMY & ASTROPHYSICS. 2017 ; Vol. 603. pagg. A39-.
@article{f17c750c22dd4ee3a60bd9d79f52953f,
title = "XMM-Newton and INTEGRAL view of the hard state of EXO 1745-248 during its 2015 outburst",
abstract = "Context. Transient low-mass X-ray binaries (LMXBs) often show outbursts that typically last a few weeks and are characterized by a high X-ray luminosity (Lx {\^a}‰ˆ 1036-1038 erg s-1), while most of the time they are found in X-ray quiescence (LX {\^a}‰ˆ 1031-1033 erg s-1). The source EXO 1745-248 is one of them. Aims. The broad-band coverage and sensitivity of the instrument on board XMM-Newton and INTEGRAL offers the opportunity of characterizing the hard X-ray spectrum during the outburst of EXO 1745-248. Methods. We report on quasi-simultaneous XMM-Newton and INTEGRAL observations of the X-ray transient EXO 1745-248 located in the globular cluster Terzan 5, performed ten days after the beginning of the outburst (on 2015 March 16) of the source between March and June 2015. The source was caught in a hard state, emitting a 0.8-100 keV luminosity of {\^a}‰ƒ 1037 erg s-1. Results. The spectral continuum was dominated by thermal Comptonization of seed photons with temperature kTin {\^a}‰ƒ 1.3 keV, by a cloud with a moderate optical depth {\"I}„ {\^a}‰ƒ 2, and with an electron temperature of kTe {\^a}‰ƒ 40 keV. A weaker soft thermal component at temperature kTth {\^a}‰ƒ 0.6-0.7 keV and compatible with a fraction of the neutron star radius was also detected. A rich emission line spectrum was observed by the EPIC-pn on board XMM-Newton; features at energies compatible with K-{\^I}± transitions of ionized sulfur, argon, calcium, and iron were detected, with a broadness compatible with either thermal Compton broadening or Doppler broadening in the inner parts of an accretion disk truncated at 20 {\^A}± 6 gravitational radii from the neutron star. Strikingly, at least one narrow emission line ascribed to neutral or mildly ionized iron is needed to model the prominent emission complex detected between 5.5 and 7.5 keV. The different ionization state and broadness suggest an origin in a region located farther from the neutron star than where the other emission lines are produced. Seven consecutive type I bursts were detected during the XMM-Newton observation, none of which showed hints of photospheric radius expansion. A thorough search for coherent pulsations from the EPIC-pn light curve did not result in any significant detection. Upper limits ranging from a few to 15{\%} on the signal amplitude were set, depending on the unknown spin and orbital parameters of the system.",
author = "{Di Salvo}, Tiziana and Rosario Iaria and Marco Matranga and Gambino, {Angelo Francesco} and {De Martino} and Burderi and Stella and Papitto and Ferrigno and Bozzo and Rea and Sanchez-Fernandez and Torres",
year = "2017",
language = "English",
volume = "603",
pages = "A39--",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",

}

TY - JOUR

T1 - XMM-Newton and INTEGRAL view of the hard state of EXO 1745-248 during its 2015 outburst

AU - Di Salvo, Tiziana

AU - Iaria, Rosario

AU - Matranga, Marco

AU - Gambino, Angelo Francesco

AU - De Martino, null

AU - Burderi, null

AU - Stella, null

AU - Papitto, null

AU - Ferrigno, null

AU - Bozzo, null

AU - Rea, null

AU - Sanchez-Fernandez, null

AU - Torres, null

PY - 2017

Y1 - 2017

N2 - Context. Transient low-mass X-ray binaries (LMXBs) often show outbursts that typically last a few weeks and are characterized by a high X-ray luminosity (Lx ≈ 1036-1038 erg s-1), while most of the time they are found in X-ray quiescence (LX ≈ 1031-1033 erg s-1). The source EXO 1745-248 is one of them. Aims. The broad-band coverage and sensitivity of the instrument on board XMM-Newton and INTEGRAL offers the opportunity of characterizing the hard X-ray spectrum during the outburst of EXO 1745-248. Methods. We report on quasi-simultaneous XMM-Newton and INTEGRAL observations of the X-ray transient EXO 1745-248 located in the globular cluster Terzan 5, performed ten days after the beginning of the outburst (on 2015 March 16) of the source between March and June 2015. The source was caught in a hard state, emitting a 0.8-100 keV luminosity of ≃ 1037 erg s-1. Results. The spectral continuum was dominated by thermal Comptonization of seed photons with temperature kTin ≃ 1.3 keV, by a cloud with a moderate optical depth τ ≃ 2, and with an electron temperature of kTe ≃ 40 keV. A weaker soft thermal component at temperature kTth ≃ 0.6-0.7 keV and compatible with a fraction of the neutron star radius was also detected. A rich emission line spectrum was observed by the EPIC-pn on board XMM-Newton; features at energies compatible with K-α transitions of ionized sulfur, argon, calcium, and iron were detected, with a broadness compatible with either thermal Compton broadening or Doppler broadening in the inner parts of an accretion disk truncated at 20 ± 6 gravitational radii from the neutron star. Strikingly, at least one narrow emission line ascribed to neutral or mildly ionized iron is needed to model the prominent emission complex detected between 5.5 and 7.5 keV. The different ionization state and broadness suggest an origin in a region located farther from the neutron star than where the other emission lines are produced. Seven consecutive type I bursts were detected during the XMM-Newton observation, none of which showed hints of photospheric radius expansion. A thorough search for coherent pulsations from the EPIC-pn light curve did not result in any significant detection. Upper limits ranging from a few to 15% on the signal amplitude were set, depending on the unknown spin and orbital parameters of the system.

AB - Context. Transient low-mass X-ray binaries (LMXBs) often show outbursts that typically last a few weeks and are characterized by a high X-ray luminosity (Lx ≈ 1036-1038 erg s-1), while most of the time they are found in X-ray quiescence (LX ≈ 1031-1033 erg s-1). The source EXO 1745-248 is one of them. Aims. The broad-band coverage and sensitivity of the instrument on board XMM-Newton and INTEGRAL offers the opportunity of characterizing the hard X-ray spectrum during the outburst of EXO 1745-248. Methods. We report on quasi-simultaneous XMM-Newton and INTEGRAL observations of the X-ray transient EXO 1745-248 located in the globular cluster Terzan 5, performed ten days after the beginning of the outburst (on 2015 March 16) of the source between March and June 2015. The source was caught in a hard state, emitting a 0.8-100 keV luminosity of ≃ 1037 erg s-1. Results. The spectral continuum was dominated by thermal Comptonization of seed photons with temperature kTin ≃ 1.3 keV, by a cloud with a moderate optical depth τ ≃ 2, and with an electron temperature of kTe ≃ 40 keV. A weaker soft thermal component at temperature kTth ≃ 0.6-0.7 keV and compatible with a fraction of the neutron star radius was also detected. A rich emission line spectrum was observed by the EPIC-pn on board XMM-Newton; features at energies compatible with K-α transitions of ionized sulfur, argon, calcium, and iron were detected, with a broadness compatible with either thermal Compton broadening or Doppler broadening in the inner parts of an accretion disk truncated at 20 ± 6 gravitational radii from the neutron star. Strikingly, at least one narrow emission line ascribed to neutral or mildly ionized iron is needed to model the prominent emission complex detected between 5.5 and 7.5 keV. The different ionization state and broadness suggest an origin in a region located farther from the neutron star than where the other emission lines are produced. Seven consecutive type I bursts were detected during the XMM-Newton observation, none of which showed hints of photospheric radius expansion. A thorough search for coherent pulsations from the EPIC-pn light curve did not result in any significant detection. Upper limits ranging from a few to 15% on the signal amplitude were set, depending on the unknown spin and orbital parameters of the system.

UR - http://hdl.handle.net/10447/238871

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

M3 - Article

VL - 603

SP - A39-

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

ER -