SAX J1808.4-3658, an accreting millisecond pulsar shining in gamma rays?

Tiziana Di Salvo, Rosario Iaria, Riggio, De Oña Wilhelmi, Rea, Sanna, Li, Burderi, Torres, Papitto

Risultato della ricerca: Article

6 Citazioni (Scopus)

Abstract

We report the detection of a possible gamma-ray counterpart of the accreting millisecond pulsar SAX J1808.4-3658. The analysis of ~6 yr of data from the Large Area Telescope on board the Fermi gamma-ray Space Telescope (Fermi-LAT) within a region of 15° radius around the position of the pulsar reveals a point gamma-ray source detected at a significance of ~6σ (test statistic TS = 32), with a position compatible with that of SAX J1808.4-3658 within the 95 per cent confidence level. The energy flux in the energy range between 0.6 and 10 GeV amounts to (2.1 ± 0.5) × 10-12 erg cm-2 s-1 and the spectrum is represented well by a power-law function with photon index 2.1 ± 0.1. We searched for significant variation of the flux at the spin frequency of the pulsar and for orbital modulation, taking into account the trials due to the uncertainties in the position, the orbital motion of the pulsar and the intrinsic evolution of the pulsar spin. No significant deviation from a constant flux at any time-scale was found, preventing a firm identification via time variability. Nonetheless, the association of the LAT source as the gamma-ray counterpart of SAX J1808.4-3658 would match the emission expected from the millisecond pulsar, if it switches on as a rotation-powered source during X-ray quiescence.
Lingua originaleEnglish
pagine (da-a)2647-2653
Numero di pagine7
RivistaMonthly Notices of the Royal Astronomical Society
Volume456
Stato di pubblicazionePublished - 2016

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energy flux
pulsars
erg
power law
gamma rays
timescale
energy
Fermi Gamma-ray Space Telescope
analysis
detection
firm
test
statistics
trial
index
confidence
switches
telescopes
orbits
deviation

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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SAX J1808.4-3658, an accreting millisecond pulsar shining in gamma rays? / Di Salvo, Tiziana; Iaria, Rosario; Riggio; De Oña Wilhelmi; Rea; Sanna; Li; Burderi; Torres; Papitto.

In: Monthly Notices of the Royal Astronomical Society, Vol. 456, 2016, pag. 2647-2653.

Risultato della ricerca: Article

Di Salvo, T, Iaria, R, Riggio, De Oña Wilhelmi, Rea, Sanna, Li, Burderi, Torres & Papitto 2016, 'SAX J1808.4-3658, an accreting millisecond pulsar shining in gamma rays?', Monthly Notices of the Royal Astronomical Society, vol. 456, pagg. 2647-2653.
Di Salvo, Tiziana ; Iaria, Rosario ; Riggio ; De Oña Wilhelmi ; Rea ; Sanna ; Li ; Burderi ; Torres ; Papitto. / SAX J1808.4-3658, an accreting millisecond pulsar shining in gamma rays?. In: Monthly Notices of the Royal Astronomical Society. 2016 ; Vol. 456. pagg. 2647-2653.
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title = "SAX J1808.4-3658, an accreting millisecond pulsar shining in gamma rays?",
abstract = "We report the detection of a possible gamma-ray counterpart of the accreting millisecond pulsar SAX J1808.4-3658. The analysis of ~6 yr of data from the Large Area Telescope on board the Fermi gamma-ray Space Telescope (Fermi-LAT) within a region of 15° radius around the position of the pulsar reveals a point gamma-ray source detected at a significance of ~6σ (test statistic TS = 32), with a position compatible with that of SAX J1808.4-3658 within the 95 per cent confidence level. The energy flux in the energy range between 0.6 and 10 GeV amounts to (2.1 ± 0.5) × 10-12 erg cm-2 s-1 and the spectrum is represented well by a power-law function with photon index 2.1 ± 0.1. We searched for significant variation of the flux at the spin frequency of the pulsar and for orbital modulation, taking into account the trials due to the uncertainties in the position, the orbital motion of the pulsar and the intrinsic evolution of the pulsar spin. No significant deviation from a constant flux at any time-scale was found, preventing a firm identification via time variability. Nonetheless, the association of the LAT source as the gamma-ray counterpart of SAX J1808.4-3658 would match the emission expected from the millisecond pulsar, if it switches on as a rotation-powered source during X-ray quiescence.",
keywords = "Astronomy and Astrophysics, Gamma-rays: stars, Space and Planetary Science, Stars: individual: SAX J1808.4-3658, Stars: neutron",
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T1 - SAX J1808.4-3658, an accreting millisecond pulsar shining in gamma rays?

AU - Di Salvo, Tiziana

AU - Iaria, Rosario

AU - Riggio, null

AU - De Oña Wilhelmi, null

AU - Rea, null

AU - Sanna, null

AU - Li, null

AU - Burderi, null

AU - Torres, null

AU - Papitto, null

PY - 2016

Y1 - 2016

N2 - We report the detection of a possible gamma-ray counterpart of the accreting millisecond pulsar SAX J1808.4-3658. The analysis of ~6 yr of data from the Large Area Telescope on board the Fermi gamma-ray Space Telescope (Fermi-LAT) within a region of 15° radius around the position of the pulsar reveals a point gamma-ray source detected at a significance of ~6σ (test statistic TS = 32), with a position compatible with that of SAX J1808.4-3658 within the 95 per cent confidence level. The energy flux in the energy range between 0.6 and 10 GeV amounts to (2.1 ± 0.5) × 10-12 erg cm-2 s-1 and the spectrum is represented well by a power-law function with photon index 2.1 ± 0.1. We searched for significant variation of the flux at the spin frequency of the pulsar and for orbital modulation, taking into account the trials due to the uncertainties in the position, the orbital motion of the pulsar and the intrinsic evolution of the pulsar spin. No significant deviation from a constant flux at any time-scale was found, preventing a firm identification via time variability. Nonetheless, the association of the LAT source as the gamma-ray counterpart of SAX J1808.4-3658 would match the emission expected from the millisecond pulsar, if it switches on as a rotation-powered source during X-ray quiescence.

AB - We report the detection of a possible gamma-ray counterpart of the accreting millisecond pulsar SAX J1808.4-3658. The analysis of ~6 yr of data from the Large Area Telescope on board the Fermi gamma-ray Space Telescope (Fermi-LAT) within a region of 15° radius around the position of the pulsar reveals a point gamma-ray source detected at a significance of ~6σ (test statistic TS = 32), with a position compatible with that of SAX J1808.4-3658 within the 95 per cent confidence level. The energy flux in the energy range between 0.6 and 10 GeV amounts to (2.1 ± 0.5) × 10-12 erg cm-2 s-1 and the spectrum is represented well by a power-law function with photon index 2.1 ± 0.1. We searched for significant variation of the flux at the spin frequency of the pulsar and for orbital modulation, taking into account the trials due to the uncertainties in the position, the orbital motion of the pulsar and the intrinsic evolution of the pulsar spin. No significant deviation from a constant flux at any time-scale was found, preventing a firm identification via time variability. Nonetheless, the association of the LAT source as the gamma-ray counterpart of SAX J1808.4-3658 would match the emission expected from the millisecond pulsar, if it switches on as a rotation-powered source during X-ray quiescence.

KW - Astronomy and Astrophysics

KW - Gamma-rays: stars

KW - Space and Planetary Science

KW - Stars: individual: SAX J1808.4-3658

KW - Stars: neutron

UR - http://hdl.handle.net/10447/209911

UR - http://mnras.oxfordjournals.org/

M3 - Article

VL - 456

SP - 2647

EP - 2653

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

ER -