A5032944978- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- High-pressure geophysics and materials
- Geophysics and Gravity Measurements
- Astrophysics and Cosmic Phenomena
- Geophysics and Sensor Technology
- Astro and Planetary Science
- Atomic and Subatomic Physics Research
- Solar and Space Plasma Dynamics
- Cosmology and Gravitation Theories
- High-Energy Particle Collisions Research
- Stellar, planetary, and galactic studies
- Quantum, superfluid, helium dynamics
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Mechanics and Biomechanics Studies
- Astronomical Observations and Instrumentation
- Particle physics theoretical and experimental studies
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Quantum Chromodynamics and Particle Interactions
- Astronomy and Astrophysical Research
- Cold Atom Physics and Bose-Einstein Condensates
- Geomagnetism and Paleomagnetism Studies
Universidad Nacional Autónoma de México
2015-2024
Michigan State University
2015
Joint Institute for Nuclear Astrophysics
2015
Ohio University
2012
Stony Brook University
1988-2012
State University of New York
1988-2012
University of Washington
2012
Pennsylvania State University
2007
Instituto de Geofísica y Astronomía
1995-2006
Columbia University
1994-1996
A new classification of neutron star cooling scenarios, involving either ``minimal'' or ``enhanced'' is proposed. The minimal scenario replaces and extends the so-called standard to include neutrino emission from Cooper pair breaking formation process. This dominates that due modified Urca process for temperatures close critical temperature superfluid pairing. Minimal distinguished enhanced by absence any direct process, nucleons exotica. Within scenario, theoretical models can be considered...
We propose that the observed cooling of neutron star in Cassiopeia A is due to enhanced neutrino emission from recent onset breaking and formation Cooper pairs (3)P(2) channel. find critical temperature for this superfluid transition ≃0.5×10(9) K. The rapidity implies protons were already a superconducting state with larger temperature. This first direct evidence superfluidity superconductivity occur at supranuclear densities within stars. Our prediction will continue several decades present...
The minimal cooling paradigm for neutron star assumes that enhanced due to neutrino emission from any direct Urca process, either nucleons or exotica such as hyperons, Bose condensates, deconfined quarks, does not occur. Previous studies showed the observed temperatures of young, cooling, isolated stars with ages between 102 and 105 yr, possible exception pulsar in supernova remnant CTA 1, are consistent predictions long 3P2 pairing gap present stellar core is moderate size. Recently, it has...
We review theoretical developments in studies of dense matter and its phase structure relevance to compact stars. Observational data on stars, which can constrain the properties matter, are presented critically interpreted.
If the thermal evolution of hot young neutron star in supernova remnant HESS J1731-347 is driven by neutrino emission, it provides a stringent constraint on coupling light (mass $\ensuremath{\ll}10\phantom{\rule{0.28em}{0ex}}\mathrm{keV}$) axion-like particles to neutrons. Using Markov-Chain Monte Carlo we find that for values axion-neutron ${g}_{ann}^{2}>7.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}20}$ (90% c.l.) axion cooling from bremsstrahlung reaction...
view Abstract Citations (170) References (28) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Cooling of Neutron Stars by the Direct URCA Process Page, Dany ; Applegate, James H. first results are reported from a program to reanalyze cooling neutron stars including direct Urca process in calculations. It is found that surface temperature young star drops dramatically after about 100 yr if allowed and nucleons do not become superfluid. If nucleon...
view Abstract Citations (156) References (63) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Surface Temperature of a Magnetized Neutron Star and Interpretation the ROSAT Data. I. Dipolar Fields Page, Dany We model temperature distribution at surface magnetized neutron star study effects on observable X-ray spectra light curves, taking fully into account gravitational lensing. Only dipolar fields are considered here. General features studied compared with...
We present a detailed, two dimensional numerical study of the microphysical conditions and dynamical evolution accretion disks around black holes when neutrino emission is main source cooling. Such structures are likely to form after gravitational collapse massive rotating stellar cores, or coalescence compact objects in binary (e.g., Hulse--Taylor system). The physical composition determined self consistently by considering regimes: neutrino--opaque neutrino--transparent, with detailed...
Two types of long-duration type I X-ray bursts have been discovered by long-term monitoring observations accreting neutron stars: superbursts and ``intermediate duration'' bursts. We investigate the sensitivity their ignition conditions to interior thermal properties star. First, we compare observed superburst light curves cooling models. Our fits require column depths in range (0.5-3) × 1012 g cm-2 an energy release ≈2 1017 ergs g-1. The implied carbon fraction is XC > 10%, constraining...
Possible effects of strangeness condensation, which has been estimated to occur in dense neutron matter at densities 2.3--3.0 times nuclear density, are calculated with special reference the cooling star probably formed SN1987A. Although center will cool much faster presence condensation than through conventional mechanisms, down T\ensuremath{\sim}2\ifmmode\times\else\texttimes\fi{}${10}^{8}$ K present time, heat conductivity is such that it take least a few tens years for this drop...
It is now possible to model thermal relaxation of neutron stars after bouts accretion during which the star heated out equilibrium by nuclear reactions in its crust. Major uncertainties these models can be encapsulated modest variations a handful control parameters that change fiducial crustal conductivity, specific heat, and heating rates. Observations constrain allow us predict longer term variability terms core temperature. We demonstrate this explicitly modeling ongoing XTE J1701-462....
It is assumed that accreting neutron stars in low-mass X-ray binaries are heated due to the compression of existing crust by freshly accreted matter which gives rise a variety nuclear reactions crust. has been shown most energy released deep pycnonuclear involving low-Z elements (the deep-crustal heating scenario). In this paper we discuss if so-called very-faint transients (VFXTs; those have outburst peak 2–10 keV luminosities <1 × 1036 erg s−1) can be used test model. We demonstrate such...
We show that the neutron star in transient system MXB 1659-29 has a core neutrino luminosity substantially exceeds of modified Urca reactions (i.e., n+n→n+p+e^{-}+ν[over ¯]_{e} and inverse) is consistent with direct (n→p+e^{-}+ν[over reaction occurring small fraction core. Observations thermal relaxation crust following 2.5 yr accretion allow us to measure energy deposited into during accretion, which then reradiated as neutrinos, infer temperature. For nucleonic core, this requires nucleons...
An accretion outburst in an X-ray transient deposits material onto the neutron star primary; this accumulation of matter induces reactions star's crust. During these heat crust out thermal equilibrium with core. When halts, cools to its long-term temperature on observable timescales. Here we examine accreting MAXI J0556-332, which is hottest transient, at start quiescence, observed date. Models quiescent light curve require a large deposition shallow outer from unknown source. The additional...
Abstract The possible detection of a compact object in the remnant SN 1987A presents an unprecedented opportunity to follow its early evolution. suspected stems from excess infrared emission dust blob near object’s predicted position. could be due decay isotopes like 44 Ti, accretion luminosity neutron star or black hole, magnetospheric wind originating spin down pulsar, thermal embedded, cooling (NS 1987A). It is shown that last possibility most plausible as other explanations are...
Baryon and quark superfluidity in the cooling of neutron stars are investigated. Future observations will allow us to constrain combinations or Lambda-hyperon pairing gaps star's mass. However, a hybrid star with mixed phase hadrons quarks, larger than few tenths an MeV render matter virtually invisible for cooling. If gap is smaller, could be important, but its effects nearly impossible distinguish from those other baryonic constituents.
We explore the thermal evolution of a neutron star undergoing episodes intense accretion, separated by long periods quiescence. By using an exact cooling code, we follow in detail flow heat due to time-dependent accretion-induced heating from pycnonuclear reactions stellar crust, surface photon emission, and neutrino cooling. These models allow us study stars soft X-ray transients. In agreement with recent work Brown, Bildsten, & Rutledge, conclude that component quiescent luminosity Aql...
We confront theoretical models for the rotational, magnetic, and thermal evolution of an ultramagnetized neutron star, or magnetar, with available data on anomalous X-ray pulsars (AXPs). argue that, if AXPs are interpreted as magnetars, their clustering spin periods between 6 12 s (observed at present in this class objects), period derivatives, luminosities, association two them young supernova remnants can only be understood globally magnetic field magnetars decays significantly a timescale...
We continue the study of effects a strong magnetic field on temperature distribution in crust magnetized neutron star (NS) and its impact observable surface temperature. Extending approach initiated Geppert et al.(2004), we consider more complex and, hence, realistic, structures but still restrict ourselves to axisymmetric configurations. put special emphasis heat blanketing effect toroidal component. show that asymmetric distributions can occur crustal consisting dipolar poloidal components...
We study the low-energy collective excitations of neutron star inner crust, where a superfluid coexists with Coulomb lattice nuclei. The dispersion relation modes is calculated systematically from microscopic theory including band structure effects. These effects are shown to lead strong mixing between Bogoliubov-Anderson bosons and longitudinal crystal phonons. In addition, speed transverse shear mode greatly reduced as large fraction neutrons entrained by Not only does much smaller...