scholarly journals The type I X-ray bursts of 4U 1735–44

2012 ◽  
Vol 8 (S290) ◽  
pp. 251-252
Author(s):  
Y. J. Lei ◽  
H. T. Zhang ◽  
Y. Q. Dong ◽  
H. L. Yuan
Keyword(s):  
Accretion Rate ◽  
Type I ◽  
X Ray ◽  
Mass Accretion Rate ◽  
Peak Flux ◽  
Low Mass

AbstractWith RXTE data ranging from 1997 August to 1998 May, we detected 8 type I X-ray bursts from the atoll source 4U 1735–44. The bursts are present at all the branches, and most occur at an inferred low mass accretion rate. We find no correlation between the peak flux of the bursts and the mass accretion rate. The results are different from that of 4U 1728-34, whose bursts' peak flux are anti-correlated with the mass accretion rate.

scholarly journals The study of multipeaked type-I X-ray bursts in the neutron star low-mass X-ray binary 4U 1636 − 536 with RXTE

2020 ◽  
Vol 501 (1) ◽  
pp. 168-178
Author(s):  
Chen Li ◽  
Guobao Zhang ◽  
Mariano Méndez ◽  
Jiancheng Wang ◽  
Ming Lyu
Keyword(s):  
Neutron Star ◽  
Flux Ratio ◽  
Light Curves ◽  
Type I ◽  
X Ray ◽  
Soft State ◽  
Peak Flux ◽  
Low Mass ◽  
Two Peaks ◽  
Second Peak

ABSTRACT We have found and analysed 16 multipeaked type-I bursts from the neutron-star low-mass X-ray binary 4U 1636 − 53 with the Rossi X-ray Timing Explorer (RXTE). One of the bursts is a rare quadruple-peaked burst that was not previously reported. All 16 bursts show a multipeaked structure not only in the X-ray light curves but also in the bolometric light curves. Most of the multipeaked bursts appear in observations during the transition from the hard to the soft state in the colour–colour diagram. We find an anticorrelation between the second peak flux and the separation time between two peaks. We also find that in the double-peaked bursts the peak-flux ratio and the temperature of the thermal component in the pre-burst spectra are correlated. This indicates that the double-peaked structure in the light curve of the bursts may be affected by enhanced accretion rate in the disc, or increased temperature of the neutron star.

scholarly journals Monitoring campaign of 1RXS J171824.2–402934, the low-mass X-ray binary with the lowest mass accretion rate

2009 ◽  
Vol 506 (2) ◽  
pp. 857-863 ◽  
Author(s):  
J. J. M. in 't Zand ◽  
P. G. Jonker ◽  
C. G. Bassa ◽  
C. B. Markwardt ◽  
A. M. Levine
Keyword(s):  
Accretion Rate ◽  
X Ray ◽  
Mass Accretion Rate ◽  
Monitoring Campaign ◽  
Low Mass

scholarly journals Thermonuclear Burst Observations for Model Comparisons: A Reference Sample

2017 ◽  
Vol 34 ◽  
Author(s):  
Duncan K. Galloway ◽  
Adelle J. Goodwin ◽  
Laurens Keek
Keyword(s):  
Accretion Rate ◽  
Numerical Models ◽  
Reference Sample ◽  
Recurrence Time ◽  
Test Cases ◽  
Type I ◽  
Time Resolved ◽  
X Ray ◽  
Peak Flux ◽  
Flux Level

AbstractWe present observations of thermonuclear (type-I) X-ray bursts, selected for comparison with numerical models. We provide examples of four distinct cases of ignition: He-ignition in mixed H/He fuel (case 1); He-ignition in pure He fuel, following exhaustion of accreted H by steady burning (case 2); ignition in (almost) pure He accumulated from an evolved donor in an ultracompact system; and a superburst, thought to arise from ignition of carbon fuel produced as a by-product of H/He bursts. For regular bursts, we measured the recurrence time and calculated averaged burst profiles from RXTE observations. We also estimated the recurrence time for pairs of bursts, including those observed during a transient outburst, modelled using a numerical ignition code. For each example we list the burst properties including recurrence time, fluence, peak flux, the persistent flux level (and inferred accretion rate), and the ratio of persistent flux to fluence. In the accompanying material, we provide a bolometric lightcurve for each burst, determined from time-resolved spectral analysis. Along with the inferred or adopted parameters for each burst system, including distance, surface gravity, and redshift, these data are suggested as suitable test cases for ignition models.

scholarly journals NuSTAR observation of GRO J1744–28 at low mass accretion rate

2020 ◽  
Vol 643 ◽  
pp. A128
Author(s):  
Ole König ◽  
Felix Fürst ◽  
Peter Kretschmar ◽  
Ralf Ballhausen ◽  
Ekaterina Sokolova-Lapa ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Accretion Rate ◽  
Compact Objects ◽  
Source Spectrum ◽  
Iron Line ◽  
X Ray ◽  
Mass Accretion Rate ◽  
Pulse Phase ◽  
Low Mass ◽  
Cyclotron Line

Context. Neutron stars in low-mass X-ray binaries are important systems for studying the physics of accretion onto compact objects. The system GRO J1744–28 is particularly interesting as it usually shows clear pulsations as well as X-ray bursts. Additionally, there are claims for a magnetic field of 5 × 1011 G through the detection of a cyclotron resonant scattering feature (CRSF). Aims. We present the spectral analysis of GRO J1744–28 using ∼29 ks of NuSTAR data taken in 2017 February at a low luminosity of 3.2 × 1036 erg s−1 (3−50 keV). Our goal is to study the variability of the source spectrum with pulse phase and to search for the claimed CRSF. Methods. The continuum spectrum was modeled with an absorbed power law with exponential cutoff, and an additional iron line component. We found no obvious indications for a CRSF, and therefore performed a detailed cyclotron line search using statistical methods. We performed this search on pulse phase-averaged spectra and on phase-resolved spectra. Results. GRO J1744–28 was observed in a low-luminosity state. The previously detected Type II X-ray bursts are absent. Clear pulsations at a period of 2.141124(9) Hz are detected. The pulse profile shows an indication of a secondary peak that was not seen at higher flux. The upper limit for the strength of a CRSF in the 3−20 keV band is 0.07 keV (90% CL), lower than the strength of the line found at higher luminosity. Conclusions. The detection of pulsations shows that the source did not enter the “propeller” regime, even though the source flux of 4.15 × 10−10 erg cm−2 s−1 was almost one order of magnitude below the threshold for the propeller regime claimed in previous studies on this source. The transition into the propeller regime in GRO J1744–28 must therefore be below a luminosity of 3.2 × 1036 erg s−1 (3−50 keV), which implies a surface magnetic field ≲2.9 × 1011 G and mass accretion rate ≲1.7 × 1016 g s−1. A change of the CRSF depth as function of luminosity is not unexpected and has been observed in other sources. This result possibly implies a change in emission geometry as function of mass accretion rate to reduce the depth of the line below our detection limit.

Quiescent luminosities of accreting neutron stars-possibility of neutrino losses due to strong pion condensations

2018 ◽  
Vol 27 (08) ◽  
pp. 1850067 ◽  
Author(s):  
Yasuhide Matsuo ◽  
HeLei Liu ◽  
Masa-aki Hashimoto ◽  
Tsuneo Noda
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Accretion Rate ◽  
Cooling Process ◽  
X Ray ◽  
Mass Accretion Rate ◽  
Star Models ◽  
Low Mass ◽  
X Ray Binaries

We construct the quiescent neutron star models in the evolutionary calculations. The X-ray luminosities have been derived in terms of the time-averaged mass accretion rate for various neutron star masses and surface compositions. We compare the quiescent luminosities observed from X-ray transients in low mass X-ray binaries, where the stellar evolutionary calculations of accreting neutron stars include neutrino cooling due to strong pion condensations. Our results based on the evolutionary calculations suggest that stronger cooling process would be necessary to be consistent with observations.

scholarly journals Searching for a link between the magnetic nature and other observed properties of Herbig Ae/Be stars

2008 ◽  
Vol 4 (S259) ◽  
pp. 395-396 ◽  
Author(s):  
Swetlana Hubrig ◽  
C. Grady ◽  
M. Schöller ◽  
O. Schütz ◽  
B. Stelzer ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Survey ◽  
Accretion Rate ◽  
Be Stars ◽  
General Correlation ◽  
X Ray ◽  
Mass Accretion Rate ◽  
Debris Disk ◽  
Magnetic Nature

AbstractWe present the results of a new magnetic field survey of Herbig Ae/Be and A debris disk stars. They are used to determine whether magnetic field properties in these stars are correlated with the mass-accretion rate, disk inclinations, companion(s), Silicates, PAHs, or show a more general correlation with age and X-ray emission as expected for the decay of a remnant dynamo.

scholarly journals A very rare triple-peaked type-I X-ray burst in the low-mass X-ray binary 4U 1636−53

2009 ◽  
Vol 398 (1) ◽  
pp. 368-374 ◽  
Author(s):  
Guobao Zhang ◽  
Mariano Méndez ◽  
Diego Altamirano ◽  
Tomaso M. Belloni ◽  
Jeroen Homan
Keyword(s):  
Type I ◽  
X Ray ◽  
Low Mass

scholarly journals New ASCA Observations of two Anomalous X-ray Pulsars

2000 ◽  
Vol 177 ◽  
pp. 695-698 ◽  
Author(s):  
B. Paul ◽  
M. Kawasaki ◽  
T. Dotani ◽  
F. Nagase
Keyword(s):  
Accretion Rate ◽  
Accretion Disc ◽  
Spectral Shape ◽  
Energy Spectra ◽  
Pulse Profile ◽  
X Ray ◽  
Low Mass ◽  
Low X ◽  
Star Surface ◽  
Made In

AbstractNewASCAobservations of two anomalous X-ray pulsars (AXP) 4U 0142+61 and 1E 1048.1-5937, made in 1998, when compared to earlier observations in 1994 show remarkable stability in the intensity, spectral shape and pulse profile. The energy spectra consist of two components, a power-law and a blackbody emission from the neutron star surface. In IE 1048.1-5937, we have identified three epochs with different spin-down rates and discuss its implications for the magnetar hypothesis of the AXPs. We also note that the spin-down rate and its variations in IE 1048.1-5937 are much larger than what normally can be produced by an accretion disc with very low mass accretion rate corresponding to its low X-ray luminosity.

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