اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدSuzaku Observation of the Symbiotic X-Ray Binary IGR J16194-2810
116
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We observed IGR J16194-2810 in the low/hard state with the Suzaku X-ray satellite in 2009. The source is a Symbiotic X-ray Binary (SyXB) classified as a category of a Low-Mass X-ray Binary (LMXB), since the system is composed of an M-type giant and probably a neutron star (NS). We detected the 0.8-50 keV signal with the XIS and HXD-PIN. The 2-10 keV luminosity was L ~ 7 x 10^34 erg s^-1 corresponding to ~10^-3 L_Edd, where L_Edd is the Eddington Luminosity of a 1.4 M_o NS and a source distance of 3.7 kpc is assumed. The luminosity is similar to those of past observations. The spectral analysis showed that there are two emission components below and above ~2 keV. The hard emission component is represented by a Comptonized black-body emission model with the seed-photon temperature ~1.0 keV and the emission radius ~700 m. The seed photon is considered to come from a small fraction of the NS surface. The soft component is reproduced by either a raw black-body (~0.4 keV, ~1.7 km) or a Comptonized emission (~0.1 keV, ~75 km). We think the origin is the emission from other part of the NS surface or the accreting stream. The physical parameters of the hard emission component of IGR J16194-2810 are compared with those of an SyXB (4U 1700+24) and LMXBs (Aql X-1 and 4U 0614+091). This comparison reveals that these SyXBs in the low/hard state have a smaller radiation region (< 1 km) on the NS surface with a higher seed-photon temperature (~1 keV) than the compared LMXBs.
قيم البحث
اقرأ أيضاً
The source IGR J17200-3116 was discovered in the hard X-ray band by INTEGRAL. A periodic X-ray modulation at ~326 s was detected in its Swift light curves by our group (and subsequently confirmed by a Swift campaign). In this paper, we report on the
analysis of all the Swift observations, which were collected between 2005 and 2011, and of a ~20 ks XMM-Newton pointing that was carried out in 2013 September. During the years covered by the Swift and XMM-Newton observations, the 1-10 keV fluxes range from ~1.5 to 4E-11 erg/cm^2/s. IGR J17200-3116 displays spectral variability as a function of the pulse phase and its light curves show at least one short (a few hundreds of seconds) dip, during which the flux dropped at 20-30% of the average level. Overall, the timing and spectral characteristics of IGR J17200-3116 point to an accreting neutron star in a high-mass system but, while the pulse-phase spectral variability can be accounted for by assuming a variable local absorbing column density, the origin of the dip is unclear. We discuss different possible explanations for this feature, favouring a transition to an ineffective accretion regime, instead of an enhanced absorption along the line of sight.
Symbiotic X-ray Binaries (SyXBs) are a recently discovered subclass of Low Mass X-ray Binaries. Their growing number makes them an important evolutionary channel of X-ray Binaries. Our goal is to perform spectral analysis and classification of the pr
oposed counterparts to IGR J16358-4726 and IGR J16393-4643 and to establish their nature as X-ray systems. We used the ESO/UT1 ISAAC spectrograph to observe the proposed counterparts to the two sources, obtaining K-band medium resolution spectra (R = 500) with a S/N > 140. Data reduction was performed with the standard procedure. We classified them by means of comparison with published atlases. We performed SED fitting in order to refine the spectral classification. The two counterparts clearly exhibit the typical features of late-type stars, notably strong CO absorption bands in the red part of the spectrum. With information from previous X-ray studies, we classify the two systems as two new members of the SyXB class. For IGR J16393-4643, we considered the most probable counterpart to the system, although three other objects cannot be completely discarded. For this system, we compared our findings with available orbital solutions, constraining the orbital parameters and the mass of the companion star. By including two more systems, we increased to eight the number of known SyXBs, which emerges as a non-negligible category of galactic X-ray binaries.
We report on the discovery of X-ray pulsations in the Be/X-ray binary IGR J21343+4738 during an XMM-Newton observation. We obtained a barycentric corrected pulse period of 320.35+-0.06 seconds. The pulse profile displays a peak at low energy that fla
ttens at high energy. The pulse fraction is 45+-3$% and independent of energy within the statistical uncertainties. The 0.2-12 keV spectrum is well fit by a two component model consisting of a blackbody with kT=0.11+-0.01 keV and a power law with photon index Gamma=1.02+-0.07. Both components are affected by photoelectric absorption with a equivalent hydrogen column density NH=(1.08+-0.15)x 10^{22} cm^{-2} The observed unabsorbed flux is 1.4x10^{-11} erg cm^{-2} s^{-1} in the 0.2-12 keV energy band. Despite the fact that the Be stars circumstellar disc has almost vanished, accretion continues to be the main source of high energy radiation. We argue that the observed X-ray luminosity (LX~10^{35} erg s^{-1}) may result from accretion via a low-velocity equatorial wind from the optical companion.
IGR J06074+2205 is a poorly studied X-ray source with a Be star companion. It has been proposed to belong to the group of Be/X-ray binaries. In Be/X-ray binaries, accretion onto the neutron star occurs via the transfer of material from the Be stars c
ircumstellar disk. Thus, in the absence of the disk, no X-ray should be detected. The main goal of this work is to study the quiescent X-ray emission of IGR J06074+2205 during a disk-loss episode. We show that at the time of the XMM-Newton observation the decretion disk around the Be star had vanished. Still, accretion appears as the source of energy that powers the high-energy radiation in IGR J06074+2205. We report the discovery of X-ray pulsations with a pulse period of 373.2 s and a pulse fraction of ~50%. The $0.4-12$ keV spectrum is well described by an absorbed power law and blackbody components with the best fitting parameters: $N_{rm H}=(6.2pm0.5) times 10^{21}$ cm$^{-2}$, $kT_{rm bb}=1.16pm0.03$ keV, and $Gamma=1.5pm0.1$ The absorbed X-ray luminosity is $L_{rm X}=1.4 times 10^{34}$ erg s$^{-1}$ assuming a distance of 4.5 kpc. The detection of X-ray pulsations confirms the nature of IGR J06074+2205 as a Be/X-ray binary. We discuss various scenarios to explain the quiescent X-ray emission of this pulsar. We rule out cooling of the neutron star surface and magnetospheric emission and conclude that accretion is the most likely scenario. The origin of the accreted material remains an open question.
In this paper we study the timing and spectral properties of Be/X-ray binary pulsar EXO 2030+375 using a $Suzaku$ observation on 2012 May 23, during a less intense Type I outburst. Pulsations were clearly detected in the X-ray light curves at a baryc
entric period of 41.2852 s which suggests that the pulsar is spinning-up. The pulse profiles were found to be peculiar e.g. unlike that obtained from the earlier Suzaku observation on 2007 May 14. A single-peaked narrow profile at soft X-rays (0.5-10 keV range) changed to a double-peaked broad profile in 12-55 keV energy range and again reverted back to a smooth single-peaked profile at hard X-rays (55-70 keV range). The 1.0-100.0 keV broad-band spectrum of the pulsar was found to be well described by three continuum models such as (i) a partial covering high energy cut-off power-law model, (ii) a partially absorbed power-law with high-energy exponential rolloff and (iii) a partial covering Negative and Positive power law with EXponential (NPEX) continuum model. Unlike earlier Suzaku observation during which several low energy emission lines were detected, a weak and narrow Iron K_alpha emission line at 6.4 keV was only present in the pulsar spectrum during the 2012 May outburst. Non-detection of any absorption like feature in 1-100 keV energy range supports the claim of absence of cyclotron resonance scattering feature in EXO 2030+375 from earlier Suzaku observation. Pulse-phase resolved spectroscopy revealed the presence of additional dense matter causing the absence of second peak from the soft X-ray pulse profiles. The details of the results are described in the paper.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
