#### Transcript r*=13.6 km MPA1 EOS

Ya. B. Zeldovich All-Moscow Seminar of Astrophysicists Plamen Fiziev LTF JINR Dubna Models of Neutron Stars without Functional Relation between the Radius and Mass 16 December 201 Moscow ? Tolman-Opehgeimer-Volkov system EOS Does the M-R relation exist at all ? Where is it coming from ??? In standard notations: Nonrelativistic limit: Nonrelativistic solution for: GR critical mass: Integrating TOV from to Realistic (to some extend) EOS for NS: A two-solar-mass neutron star 2 8 O C T O B E R 2 0 1 0 | VO L 4 6 7 | N AT U R E | 1 0 8 1 arXiv:1011.4291: THE NEUTRON STAR MASS DISTRIBUTION R.Valentim, E. Rangel and J.E. Horvath arXiv:1101.4872: Mass distribution of neutron stars B. Kızıltan, A. Kottas. S. E. Thorsett Neutron stars in double neutron star and neutron star-white dwarf systems show consistent respective peaks at 1.35M⊙ and 1.50M⊙. The results strongly suggest the existence of a bimodal distribution of the masses, with the first peak around 1.37M⊙, a much wider second peak at 1.73M⊙. 2011 ApJ 742 1 (November, the 2-nd) arXiv:1106.3131 Denis A. Leahy, Sharon M. Morsink and Yi Chou The accreting millisecond pulsar XTE J1807-294 is studied through a pulse-shape modeling analysis. The model includes blackbody and Comptonized emission from the one visible hot spot and makes use of the Oblate Schwarzschild approximation for ray-tracing. We include a scattered light contribution, which accounts for flux scattered off an equatorial accretion disk to the observer including time delays in the scattered light. We give limits to mass and radius for XTE J1807-294 and compare these to limits determined for SAX J1808-3658 and XTE J1814-334 previously determined using similar methods. The resulting allowed region for mass-radius curves is small but consistent with a mass-radius relation with nearly constant radius (~12 km) for masses between 1 and 2.5 solar masse. As long as an EOS mass-radius curve has sections that pass through each of the star’s 3 σ allowed regions, it will be allowed by all 3 stars’ data. NO ONE of the EOS curves in the figure possess this property. Excluded 10 soft EoS (arXiv:1108.2166) ps, prak_data, schaf2, schaf1, pclnphq, pal2, ms1506, gm3nph, gm2nph, gm1nph XTE J1814-338 XTE J1807-294 SAX J1808 Warning: the star rotation still not taken into account !!! Excluded 10 stiff EoS (arXiv:1108.2166) wff1, wff2, wff3, wff4, MPA1, ms2, ms00, engvik, AP1, AP2, AP3, AP4 XTE J1814-338 XTE J1807-294 SAX J1808 Warning: the star rotation still not taken into account !!! Still remain 2 stiff EoS: AP3 and MPA1 ??? Observations versus EoS Ap3 and MPA1 AP3 MPA1 XTE J1814-338 SAX J1808 XTE J1807-294 Warning: the star rotation still not taken into account !!! XTE J1807-294 AP3 MPA1 XTE J1814-338 SAX J1808 m*- r* relation does not exist in the Nature!!! Christian D. Ott, Evan P. O'Connor, Basudeb Dasgupta, arXiv:1111.6282 The figure shows that none of the current set of available EOS allow for a 2-M neutron star while at the same time being consistent with the current massradius constraints from observations. The crux is that the EOS needs to be sufficiently stiff to support 2-M neutron stars and at the same time sufficiently soft to make neutron stars with moderate radii n the canonical mass range. This balance appears to be difficult to realize. The stiff set of RMF EOS produce systematically too large neutron stars. The soft compressible liquid-droplet LS180 EOS agrees well with the mass-radius constraints, but is ruled out by its failure to support a 2-M neutron star. Mass-radius relations for 10 publically available finite temperature EOS along with several constraints. Ozel et al. analyzed three accreting and bursting neutron star systems and derived mass-radius regions shown in green. Steiner et al. performed a combined anaylsis of six accreting neutron star systems, shown are 1- and 2- results in blue. An old problem: Comparizon of the interior and exterior mass – radius relations Ap&SS.234...39L, 1995 A more recent results: ? What is the situation now ? A.M.Cherepashchuk, talk at 15th Lomonosov Conference, 18 of August, 2011, Moscow State University HNXB + LMXB NS BH candidates It seems to be strange because the number of stars in the Galaxy – progenitors of BHs (M > 30 M) is strongly increasing with decreasing of their masses: N ~ M - 5. Exploding Star The Number of the BH candidates does not increase with decreasing of their masses. Neutron Star Discovered Where a Black Hole Was Expected November 02, 2005, Westerlund 1 A very massive star collapsed to form a neutron star and not a black hole as expected, according to new results from NASA's Chandra X-ray Observatory. This discovery shows that nature has a harder time making black holes than previously thought. Scientists found this neutron star -- a dense whirling ball of neutrons about 12 miles in diameter -- in an extremely young star cluster. Astronomers were able to use welldetermined properties of other stars in the cluster to deduce that the progenitor of this neutron star was at least 40 times the mass of the Sun. "Our discovery shows that some of the most massive stars do not collapse to form black holes as predicted, but instead form neutron stars." said Michael Muno, a UCLA postdoctoral Hubble Fellow and lead author of a paper to be published in The Astrophysical Journal Letters. Muno and colleagues discovered a pulsing neutron star in a cluster of stars known as Westerlund 1. This cluster contains a hundred thousand or more stars in a region only 30 light years across, which suggests that all the stars were born in a single episode of star formation. Based on optical properties such as brightness and color some of the normal stars in the cluster are known to have masses of about 40 suns. Since the progenitor of the neutron star has already exploded as a supernova, its mass must have been more than 40 solar masses. Matt Visser, Black holes in general relativity. Do black holes “exist” ? PoS BHs,GR andS trings 2008: 001, 2008, arXiv:0901.4365 “This innocent question is more subtle than one might expect, and the answer depends very much on whether one is thinking as an observational astronomer, a classical general relativist, or a theoretical physicist.” Astronomers have certainly seen things that are small, dark, and heavy. Classical general relativist: Eternal black holes certainly exist mathematically. Theoretical physicist: We have not seen direct observational evidence of the event horizon. The mathematical solutions suffer essential physical shortcomings ! Visser M, Barcelo C, Liberati S, Sonego S: gr-qc/0902.0346 Small, dark, and heavy: But is it a black hole? The Mass and the spin of the Black Hole(?)in Cygnus X-1 arXiv:1106.3688, 1106.3689,1106.3690 O-type supergiant Distnace 1.86 +0.12 −0.11 kpc Kerr black hole (?) with a spin parameter a∗ > 0.97 (3 σ) News: arXiv:1110.4374: A weak compact jet in a soft state of Cygnus X-1 New Models of Neutron Stars without Mass-Radius Relation Some geometry An auxiliary Euclidean 3D space: 3D spherically symmetric Riemannian space: The area: The radial distance: The volume: Familiar case: Unusual case: The spherically symmetric 3D geometry in terms of area radius (Hilbert gauge 1917): The original Schwarzschild solution (1916) tt The center is at the metric singularity ! How it could be ?!? A point with a finite surface!!! Yes! It exists in GR! Area blowing around the center: |dl|=|ds|: dt=0, dθ=0, dϕ=0 Where M-R relation is coming from in the relativistic problem R*, M* In general case If c The real situation for WD: , Springer, 2000 Theory with VERSUS PF: arXiv:astro-ph/0409456 - Observations for 1175 WD Madej et al.: arXiv:astro-ph/0404344 TOV EOS r*=13.6 km rc(m*,r*)>0 rc(m*,r*)=0 r*=13.6 km rc(m*,r*)>0 Generalized TOV NS: more details r*=13.6 km r*=13.6 km r*=13.6 km r*=13.6 km c The new theoretical model A striking mass gap arXiv:1110.1635 The domain of nonstable NS = GRB ??? Different type of SN explosions? or Different type of NS ? MPA1 EOS Analytical EOS for NS Haensel, P., & Potekhin, A. Y. 2004, A&A, 428, 191. C. Gungor, K. Y. EksiarXiv:1108.2166 MPA1 EOS r*=13.6 km r*=13.6 km rc(m*,r*)>0 rc(m*,r*)>0 r*=13.6 km rc(m*,r*)>0 r*=13.6 km rc(m*,r*)>0 MPA1 EOS r*=13.6 km r*=13.6 km r*=13.6 km r*=13.6 km r*=13.6 km A negative mass deffect Instability MPA1 EOS Strong instability and explosion of the light neutron stars: m*ʘ < 0.3 r*km = 13.6 r*=13.6 km r*=13.6 km r*=13.6 km MPA1 EOS For r* = 13.6 km m min = 0.3463 ʘ r*=13.6 km EOS pal2 NASA's WISE Mission Captures Black Hole's Wildly Flaring Jet WISE images showing strong bursts and dimming of infrared light in the ”black hole” GX 339-4. The data cover a period of approximately 1 day, speeded up. arXiv:1109.4064 Temporal analysis of long and short GRB light curves carried out here supports the 83 general observation that the short bursts are temporally similar to long ones but compressed 384 in time, which could be related to the nature of the central engine of the respective bursts. A A sample pulse fit to one long burst GRB080723D (upper plot) and one short burst GRB090227B (lower plot). The histogram in black is the GRB light curve and the fitted background is shown as black dashed line. The pulses shown in green are the lognormal pulses fitted to those in the light curves. The sum of the background model and the fitted pulses is shown as purple continuous line. The goodness of fit parameter, n, is indicated at the top right corner of each plot. Sample pulse fits to the lowest 6 energy channels of NaI and the full energy range light curve from BGO detector of a long GRB 090626A. Thank You Some suspected to be BH objects: astro-ph/0808.0435 arXiv:0911.5408v1 [astro-ph.HE] The Schwarzschild radii and the geometrical radii of some astrophysical objects Moon 0.018 cm 1,737 km Earth Sun SgrA Galaxy 1.5 cm 3 km 1.3x107 5.4x1011 6,378 km 7x105 km km km 5 x 1014 km Dr. Neil Gehrels of NASA Goddard Space Flight Center, Greenbelt, Md., Swift principal investigator. "None of this was realized before simply because we couldn't get to the scene of the explosion fast enough." "Swift has the unique ability to detect bursts and turn its X-ray and ultravioletoptical telescopes to the explosion's embers within minutes. As such, Swift is detecting new burst details that might rewrite theory." A new 2008 result: astro-ph/0804-1856 The mass of the progenators of long duration GRB (Witnessing the real death of massive stars) For star population ~ 5 Myr > 50 Solar masses For star population ~ 8 Myr > 25 Solar masses For star population < 7 Myr > 20 Solar masses Nevertheless, in the collapse which leads to long duration GRB BH do not form at least in the “classical” way. astro-ph/0805.014 arXiv: 1110.4758 GRBs from INTEGRAL arXiv:1108.0638 The longest observed GRB110328 arXiv:1109.3018