The cooling phase of Type I X-ray bursts observed with RXTE in 4U 1820−30 does not follow the canonical F ∝ T4 relation

  title={The cooling phase of Type I X-ray bursts observed with RXTE in 4U 1820−30 does not follow the canonical F ∝ T4 relation},
  author={Federico Garc'ia and Guobao Zhang and Mariano M'endez IAR-CONICET and A. I. Bogomazov 1- Sternberg Astronomical Institute and Groningen and The Netherlands.},
  journal={Monthly Notices of the Royal Astronomical Society},
We analysed the complete set of bursts from the neutron star low-mass X-ray binary 4U 1820-30 detected with the Rossi X-ray Timing Explorer (RXTE). We found that all are photospheric radius expansion bursts, and have similar duration, peak flux and fluence. From the analysis of time-resolved spectra during the cooling phase of the bursts, we found that the relation between the bolometric flux and the temperature is very different from the canonical F ∝ T4 relation which is expected if the… 

Figures and Tables from this paper

The influence of accretion geometry on the spectral evolution during thermonuclear (type I) X-ray bursts

Neutron star (NS) masses and radii can be estimated from observations of photospheric radius-expansion X-ray bursts, provided the chemical composition of the photosphere, the spectral

The link between coherent burst oscillations, burst spectral evolution and accretion state in 4U 1728–34

Coherent oscillations and the evolution of the X-ray spectrum during thermonuclear X-ray bursts in accreting neutron-star X-ray binaries have been studied intensively but separately. We analysed all

Broad-band X-ray emission and the reality of the broad iron line from the neutron star–white dwarf X-ray binary 4U 1820−30

Broad relativistic iron lines from neutron star X-ray binaries are important probes of the inner accretion disc. The X-ray reflection features can be weakened due to strong magnetic fields or very


Photospheric radius expansion (PRE) bursts have already been used to constrain the masses and radii of neutron stars. RXTE observed three PRE bursts in 4U 1746-37, all with low touchdown fluxes. We

Observational Constraints on Neutron Star Masses and Radii

Precise and reliable measurements of the masses and radii of neutron stars with a variety of masses would provide valuable guidance for improving models of the properties of cold matter with

Phase transitions in neutron stars and their links to gravitational waves

The recent direct observation of gravitational wave event $GW170817$ and its $GRB170817A$ signal has opened up a new window to study neutron stars and heralds a new era of Astronomy referred to as

Basic parameters of the helium-accreting X-ray bursting neutron star in 4U 1820−30

The ultracompact low-mass X-ray binary 4U 1820-30 situated in the globular cluster NGC 6624 has an orbital period of only ≈11.4 min, which likely implies a white dwarf companion. The observed X-ray

Flux decay during thermonuclear X-ray bursts analysed with the dynamic power-law index method

The cooling of type-I X-ray bursts can be used to probe the nuclear burning conditions in neutron star envelopes. The flux decay of the bursts has been traditionally modelled with an exponential, e

Astrophysical Constraints on Dense Matter in Neutron Stars

  • M. Miller
  • Physics
    Timing Neutron Stars: Pulsations, Oscillations and Explosions
  • 2020
Ever since the discovery of neutron stars it has been realized that they serve as probes of a physical regime that cannot be accessed in laboratories: strongly degenerate matter at several times

Atmospheric monitoring at the site of the Telescopio Nazionale Galileo

For more than 20 years, the atmosphere above the Telescopio Nazionale Galileo and its surroundings at the Roque de Los Muchachos Observatory have been monitored. From the first instruments installed



The cooling phase of Type I X-ray bursts in 4U 1636-53

Time-resolved spectra during the cooling phase of thermonuclear X-ray bursts in low- mass X-ray binaries (LMXBs) can be used to measure the radii and masses of neutron stars. We analyzed 300 bursts


Thermal emission during X-ray bursts is a powerful tool for determining neutron star (NS) masses and radii if the Eddington flux and the apparent radius in the cooling tail can be measured accurately

XMM-Newton observation of 4U 1820-30: broad band spectrum and the contribution of the cold interstellar medium

We present an analysis of the bright X-ray binary 4U 1820-30, thet is based mainly on XMM-Newton-RGS data, in addition to complementary data from XMM-Newton-EPIC-pn, INTEGRAL, and Chandra-HETG, to

A Remarkable 3 Hour Thermonuclear Burst from 4U 1820–30

We present a detailed observational and theoretical study of a ~3 hr long X-ray burst (the "superburst") observed by the Rossi X-Ray Timing Explorer (RXTE) from the low-mass X-ray binary 4U 1820-30.

Thermonuclear (Type I) X-Ray Bursts Observed by the Rossi X-Ray Timing Explorer

We have assembled a sample of 1187 thermonuclear (type I) X-ray bursts from observations of 48 accreting neutron stars by the Rossi X-ray Timing Explorer, spanning more than 10 years. The sample

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

We have discovered a triple-peaked X-ray burst from the low-mass X-ray binary (LMXB) 4U 1636-53 with the Rossi X-ray Timing Explorer (RXTE). This is the first triple-peaked burst reported from any

Models of Type I X-Ray Bursts from 4U 1820–30

I present ignition models for type I X-ray bursts and superbursts from the ultracompact binary 4U 1820-30. A pure helium secondary is usually assumed for this system (which has an orbital period ≈11

X-ray bursts at extreme mass accretion rates from GX 17+2

We report on ten type I X-ray bursts originating from GX 17+2 in data obtained with the RXTE/PCA in 1996-2000. Three bursts were short in duration (∼10 s), whereas the others lasted for ∼6-25 min.

Photospheric radius expansion X-ray bursts as standard candles

We examined the maximum bolometric peak luminosities during type I X-ray bursts from the persistent or transient luminous X-ray sources in globular clusters. We show that for about two thirds of the

Superexpansion as a possible probe of accretion in 4U 1820-30

The ultracompact X-ray binary 4U 1820-30 is well known for its≈170-d superorbital modulation in X-ray flux and spectrum, an d the exclusiveness of bursting behavior to the low hard ’island’ state. In