Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · astro-ph/9912480

The Reappearance of the Transient Low Mass X-ray Binary X1658-298

Stefanie Wachter·Alan P. Smale·Charles Bailyn
View original source ↗Read source document ↗Export metadata ↓

Abstract

In April 1999 the transient low mass X-ray binary X1658-298 resumed its strong and persistent X-ray emission after a 21-year interval of quiescence. We present RXTE data obtained soon after the reappearance, including four eclipses with a mean duration of 901.9 +/- 0.8 sec and ingress/egress times of 6-13 sec. Our updated ephemeris for the source indicates that the 7.1-hr orbital period of the system is decreasing with a timescale of 10^7 yr. Contemporaneous optical observations provide the first-ever lightcurve of V2134 Oph, the optical counterpart of X1658-298. The optical modulation is highly variable from night to night and exhibits a distinct, narrow eclipse feature of about 0.2 mag superposed on a gradual brightness variation with ~0.7-0.8 mag amplitude. Our data indicate that there is no significant offset between the time of mid-eclipse in the X-ray and optical and that the narrow optical eclipse feature is of the same duration as the X-ray eclipse. This implies an accretion disk structure characterized by enhanced optical emission coincident with the central X-ray emitting area.

Explore related subjects

astro-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Stefanie Wachter, Alan P. Smale, Charles Bailyn. 1999-12-22. The Reappearance of the Transient Low Mass X-ray Binary X1658-298. https://doi.org/10.1086/308754

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Frame covariance of CMBR lensing in the exact 1+3 covariant radiation hierarchy

The exact $1+3$ covariant Boltzmann hierarchy for the cosmic microwave background contains acceleration, shear and vorticity couplings whose coefficients grow linearly in $\ell$. We show that all are the multipole form of the aberration operator in the photon Liouville equation. Under a change of threading, this operator shifts by the along-ray generator of a Lorentz boost. The acceleration coupling of $\ell$ to $\ell\pm1$ and the shear coupling of $\ell$ to $\ell\pm2$ are therefore frame-covariant descriptions of the same operator, related by an algebraic, pointwise relabelling of direction. With emitter and observer frames fixed, the observed sky is independent of the intermediate threading at every $\ell$. We derive this in $1+3$ covariant and gauge-invariant variables without constructing second-order gauge-invariant variables. The $O(ε^2\ell)$ content is gravitational lensing, as known in metric variables. Linearisation about a Friedmann--Lemaître--Robertson--Walker background removes these couplings, requiring lensing to be reinstated from the geodesic equation. Keeping the threading arbitrary makes frame covariance explicit and places observer aberration in the same operator. In the Newtonian threading we compute both halves of the deflection: the equivalence-principle contribution enters through aberration, while the spatial-curvature contribution arises from free streaming on perturbed spatial sections and reduces to the same operator. The lensing efficiency follows from the direction derivative. The angular-power-spectrum contribution is quartic in the potential: for a deflection statistically independent of the source, the two fourth-order terms carrying $\ell^2$ cancel where the spectrum is smooth on the deflection scale, and lensing redistributes power without adding ensemble variance.

astro-ph↗
arXiv2026

Cosmic Conundrums with Quantum Corrections

Darh energy was discovered over 25 years ago and we do not have an explanation of it. Dark matter comprises 95% of matter in the universe and we still don't know what it is. The Webb telescope has been finding fully formed galaxies with massive black holes millions of times the mass of the sun in the early universe and we don't have any explanation. A quantum density limitation will be used to solve these and other outstanding problems.

astro-ph↗
arXiv2026

On binary pulsars and the force of gravity

The energy-momentum budget of the astrophysical systems can be studied by the exact local conservation equation derived by Landau and Lifshitz. We show that a similar equation is valid for the Einstein-Cartan gravity. We reanalyze a binary pulsar system using the Landau-Lifshitz conservation equation and show that the orbital period change rate can be completely understood as a curvature backreaction process. Taking into account the detailed theoretical and observational research of relativistic binary pulsar systems, especially the system of Hulse and Taylor, we conclude that general relativity and astrophysical observations rule out the existence of gravitational radiation. We comment upon the LIGO GW events and their alternative explanation, as well as the recent pulsar timing arrays data.

astro-ph↗