Pulsar Timing and Its Applications B
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Arxiv:2009.10649V3 [Astro-Ph.CO] 30 Jul 2021
CERN-TH-2020-157 DESY 20-154 From NANOGrav to LIGO with metastable cosmic strings Wilfried Buchmuller,1, ∗ Valerie Domcke,2, 3, † and Kai Schmitz2, ‡ 1Deutsches Elektronen Synchrotron DESY, 22607 Hamburg, Germany 2Theoretical Physics Department, CERN, 1211 Geneva 23, Switzerland 3Institute of Physics, Laboratory for Particle Physics and Cosmology, EPFL, CH-1015, Lausanne, Switzerland (Dated: August 2, 2021) We interpret the recent NANOGrav results in terms of a stochastic gravitational wave background from metastable cosmic strings. The observed amplitude of a stochastic signal can be translated into a range for the cosmic string tension and the mass of magnetic monopoles arising in theories of grand unification. In a sizable part of the parameter space, this interpretation predicts a large stochastic gravitational wave signal in the frequency band of ground-based interferometers, which can be probed in the very near future. We confront these results with predictions from successful inflation, leptogenesis and dark matter from the spontaneous breaking of a gauged B−L symmetry. Introduction nal is too small to be observed by Virgo [17], LIGO [18] The direct observation of gravitational waves (GWs) and KAGRA [19] but will be probed by LISA [20] and generated by merging black holes [1{3] has led to an in- other planned GW observatories. creasing interest in further explorations of the GW spec- In this Letter we study a further possibility, metastable trum. Astrophysical sources can lead to a stochastic cosmic strings. Recently, it has been shown that GWs gravitational background (SGWB) over a wide range of emitted from a metastable cosmic string network can frequencies, and the ultimate hope is the detection of a probe the seesaw mechanism of neutrino physics and SGWB of cosmological origin. -
Negreiros Lecture II
General Relativity and Neutron Stars - II Rodrigo Negreiros – UFF - Brazil Outline • Compact Stars • Spherically Symmetric • Rotating Compact Stars • Magnetized Compact Stars References for this lecture Compact Stars • Relativistic stars with inner structure • We need to solve Einstein’s equation for the interior as well as the exterior Compact Stars - Spherical • We begin by writing the following metric • Which leads to the following components of the Riemman curvature tensor Compact Stars - Spherical • The Ricci tensor components are calculated as • Ricci scalar is given by Compact Stars - Spherical • Now we can calculate Einstein’s equation as 휇 • Where we used a perfect fluid as sources ( 푇휈 = 푑푖푎푔(휖, 푃, 푃, 푃)) Compact Stars - Spherical • Einstein’s equation define the space-time curvature • We must also enforce energy-momentum conservation • This implies that • Where the four velocity is given by • After some algebra we get Compact Stars - Spherical • Making use of Euler’s equation we get • Thus • Which we can rewrite as Compact Stars - Spherical • Now we introduce • Which allow us to integrate one of Einstein’s equation, leading to • After some shuffling of Einstein’s equation we can write Summary so far... Metric Energy-Momentum Tensor Einstein’s equation Tolmann-Oppenheimer-Volkoff eq. Relativistic Hydrostatic Equilibrium Mass continuity Stellar structure calculation Microscopic Ewuation of State Macroscopic Composition Structure Recapitulando … “Feed” with diferente microscopic models Microscopic Ewuation of State Macroscopic Composition Structure Compare predicted properties with Observed data. Rotating Compact Stars • During its evolution, compact stars may acquire high rotational frequencies (possibly up to 500 hz) • Rotation breaks spherical symmetry, increasing the degrees of freedom. -
Exploring Pulsars
High-energy astrophysics Explore the PUL SAR menagerie Astronomers are discovering many strange properties of compact stellar objects called pulsars. Here’s how they fit together. by Victoria M. Kaspi f you browse through an astronomy book published 25 years ago, you’d likely assume that astronomers understood extremely dense objects called neutron stars fairly well. The spectacular Crab Nebula’s central body has been a “poster child” for these objects for years. This specific neutron star is a pulsar that I rotates roughly 30 times per second, emitting regular appar- ent pulsations in Earth’s direction through a sort of “light- house” effect as the star rotates. While these textbook descriptions aren’t incorrect, research over roughly the past decade has shown that the picture they portray is fundamentally incomplete. Astrono- mers know that the simple scenario where neutron stars are all born “Crab-like” is not true. Experts in the field could not have imagined the variety of neutron stars they’ve recently observed. We’ve found that bizarre objects repre- sent a significant fraction of the neutron star population. With names like magnetars, anomalous X-ray pulsars, soft gamma repeaters, rotating radio transients, and compact Long the pulsar poster child, central objects, these bodies bear properties radically differ- the Crab Nebula’s central object is a fast-spinning neutron star ent from those of the Crab pulsar. Just how large a fraction that emits jets of radiation at its they represent is still hotly debated, but it’s at least 10 per- magnetic axis. Astronomers cent and maybe even the majority. -
Neutron Stars
Chandra X-Ray Observatory X-Ray Astronomy Field Guide Neutron Stars Ordinary matter, or the stuff we and everything around us is made of, consists largely of empty space. Even a rock is mostly empty space. This is because matter is made of atoms. An atom is a cloud of electrons orbiting around a nucleus composed of protons and neutrons. The nucleus contains more than 99.9 percent of the mass of an atom, yet it has a diameter of only 1/100,000 that of the electron cloud. The electrons themselves take up little space, but the pattern of their orbit defines the size of the atom, which is therefore 99.9999999999999% Chandra Image of Vela Pulsar open space! (NASA/PSU/G.Pavlov et al. What we perceive as painfully solid when we bump against a rock is really a hurly-burly of electrons moving through empty space so fast that we can't see—or feel—the emptiness. What would matter look like if it weren't empty, if we could crush the electron cloud down to the size of the nucleus? Suppose we could generate a force strong enough to crush all the emptiness out of a rock roughly the size of a football stadium. The rock would be squeezed down to the size of a grain of sand and would still weigh 4 million tons! Such extreme forces occur in nature when the central part of a massive star collapses to form a neutron star. The atoms are crushed completely, and the electrons are jammed inside the protons to form a star composed almost entirely of neutrons. -
II Publications, Presentations
II Publications, Presentations 1. Refereed Publications Izumi, K., Kotake, K., Nakamura, K., Nishida, E., Obuchi, Y., Ohishi, N., Okada, N., Suzuki, R., Takahashi, R., Torii, Abadie, J., et al. including Hayama, K., Kawamura, S.: 2010, Y., Ueda, A., Yamazaki, T.: 2010, DECIGO and DECIGO Search for Gravitational-wave Inspiral Signals Associated with pathfinder, Class. Quantum Grav., 27, 084010. Short Gamma-ray Bursts During LIGO's Fifth and Virgo's First Aoki, K.: 2010, Broad Balmer-Line Absorption in SDSS Science Run, ApJ, 715, 1453-1461. J172341.10+555340.5, PASJ, 62, 1333. Abadie, J., et al. including Hayama, K., Kawamura, S.: 2010, All- Aoki, K., Oyabu, S., Dunn, J. P., Arav, N., Edmonds, D., Korista sky search for gravitational-wave bursts in the first joint LIGO- K. T., Matsuhara, H., Toba, Y.: 2011, Outflow in Overlooked GEO-Virgo run, Phys. Rev. D, 81, 102001. Luminous Quasar: Subaru Observations of AKARI J1757+5907, Abadie, J., et al. including Hayama, K., Kawamura, S.: 2010, PASJ, 63, S457. Search for gravitational waves from compact binary coalescence Aoki, W., Beers, T. C., Honda, S., Carollo, D.: 2010, Extreme in LIGO and Virgo data from S5 and VSR1, Phys. Rev. D, 82, Enhancements of r-process Elements in the Cool Metal-poor 102001. Main-sequence Star SDSS J2357-0052, ApJ, 723, L201-L206. Abadie, J., et al. including Hayama, K., Kawamura, S.: 2010, Arai, A., et al. including Yamashita, T., Okita, K., Yanagisawa, TOPICAL REVIEW: Predictions for the rates of compact K.: 2010, Optical and Near-Infrared Photometry of Nova V2362 binary coalescences observable by ground-based gravitational- Cyg: Rebrightening Event and Dust Formation, PASJ, 62, wave detectors, Class. -
Brochure Pulsar Multifunction Spectroscopy Service Complete Cased Hole Formation Evaluation and Reservoir Saturation Monitoring from A
Pulsar Multifunction spectroscopy service Introducing environment-independent, stand-alone cased hole formation evaluation and saturation monitoring 1 APPLICATIONS FEATURES AND BENEFITS ■ Stand-alone formation evaluation for diagnosis of bypassed ■ Environment-independent reservoir saturation monitoring ■ High-performance pulsed neutron generator (PNG) hydrocarbons, depleted reservoirs, and gas zones in any formation water salinity ● Optimized pulsing scheme with multiple square and short ● Differentiation of gas-filled porosity from very low porosity ● Production fluid profile determination for any well pulses for clean separation in measuring both inelastic and formations by using neutron porosity and fast neutron cross inclination: horizontal, deviated, and vertical capture gamma rays 8 section (FNXS) measurements ● Detection of water entry and flow behind casing ● High neutron output of 3.5 × 10 neutron/s for greater ■ measurement precision Petrophysical evaluation with greater accuracy by accounting ● Gravel-pack quality determination by using for grain density and mineral properties in neutron porosity elemental spectroscopy ■ State-of-the-art detectors ■ Total organic carbon (TOC) quantified as the difference ■ Metals for mining exploration ● Near and far detectors: cerium-doped lanthanum bromide between the measured total carbon and inorganic carbon ■ High-resolution determination of reservoir quality (RQ) (LaBr3:Ce) ■ Oil volume from TOC and completion quality (CQ) for formation evaluation ● Deep detector: yttrium aluminum perovskite -
The Star Newsletter
THE HOT STAR NEWSLETTER ? An electronic publication dedicated to A, B, O, Of, LBV and Wolf-Rayet stars and related phenomena in galaxies ? No. 70 2002 July-August http://www.astro.ugto.mx/∼eenens/hot/ editor: Philippe Eenens http://www.star.ucl.ac.uk/∼hsn/index.html [email protected] ftp://saturn.sron.nl/pub/karelh/uploads/wrbib/ Contents of this newsletter Call for Data . 1 Abstracts of 12 accepted papers . 2 Abstracts of 2 submitted papers . 10 Abstracts of 6 proceedings papers . 11 Jobs .......................................................................13 Meetings ...................................................................14 Call for Data The multiplicity of 9 Sgr G. Rauw and H. Sana Institut d’Astrophysique, Universit´ede Li`ege,All´eedu 6 Aoˆut, BˆatB5c, B-4000 Li`ege(Sart Tilman), Belgium e-mail: [email protected], [email protected] The non-thermal radio emission observed for a number of O and WR stars implies the presence of a small population of relativistic electrons in the winds of these objects. Electrons could be accelerated to relativistic velocities either in the shock region of a colliding wind binary (Eichler & Usov 1993, ApJ 402, 271) or in the shocks due to intrinsic wind instabilities of a single star (Chen & White 1994, Ap&SS 221, 259). Dougherty & Williams (2000, MNRAS 319, 1005) pointed out that 7 out of 9 WR stars with non-thermal radio emission are in fact binary systems. This result clearly supports the colliding wind scenario. In the present issue of the Hot Star Newsletter, we announce the results of a multi-wavelength campaign on the O4 V star 9 Sgr (= HD 164794; see the abstract by Rauw et al.). -
R-Process Elements from Magnetorotational Hypernovae
r-Process elements from magnetorotational hypernovae D. Yong1,2*, C. Kobayashi3,2, G. S. Da Costa1,2, M. S. Bessell1, A. Chiti4, A. Frebel4, K. Lind5, A. D. Mackey1,2, T. Nordlander1,2, M. Asplund6, A. R. Casey7,2, A. F. Marino8, S. J. Murphy9,1 & B. P. Schmidt1 1Research School of Astronomy & Astrophysics, Australian National University, Canberra, ACT 2611, Australia 2ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Australia 3Centre for Astrophysics Research, Department of Physics, Astronomy and Mathematics, University of Hertfordshire, Hatfield, AL10 9AB, UK 4Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA 5Department of Astronomy, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden 6Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85741 Garching, Germany 7School of Physics and Astronomy, Monash University, VIC 3800, Australia 8Istituto NaZionale di Astrofisica - Osservatorio Astronomico di Arcetri, Largo Enrico Fermi, 5, 50125, Firenze, Italy 9School of Science, The University of New South Wales, Canberra, ACT 2600, Australia Neutron-star mergers were recently confirmed as sites of rapid-neutron-capture (r-process) nucleosynthesis1–3. However, in Galactic chemical evolution models, neutron-star mergers alone cannot reproduce the observed element abundance patterns of extremely metal-poor stars, which indicates the existence of other sites of r-process nucleosynthesis4–6. These sites may be investigated by studying the element abundance patterns of chemically primitive stars in the halo of the Milky Way, because these objects retain the nucleosynthetic signatures of the earliest generation of stars7–13. -
Optical Observations of Pulsars: the ESO Contribution R.P
Figure 3: The normalised spectral energy distribution of 3 galaxies. From left to right we show a regular Ly-break galaxy (Fig. 2c), the “spiral” galaxy (Fig. 2d), and the very red galaxy from Figure 2e. The red continuum feature of the last two galaxies can be due to the Balmer/4000 Angstrom break or due to dust. Only one of these would be selected by the regular Ly-break selection technique, as the others are too faint in the optical (rest-frame UV). Acknowledgement References van Dokkum, P. G., Franx, M., Fabricant, D., Kelson, D., Illingworth, G. D., 2000, sub- Dickinson, M., et al, 1999, preprint, as- It is a pleasure to thank the staff at mitted to ApJ. troph/9908083. Steidel, C. C., Giavalisco, M., Pettini, M., ESO who contributed to the construc- Gioia, I., and Luppino, G. A., 1994, ApJS, tion and operation of the VLT and Dickinson, M., Adelberger, K. L., 1996, 94, 583. ApJL, 462, L17. ISAAC. This project has only been van Dokkum, P. G., Franx, M., Fabricant, D., Williams, R. E., et al, 2000, in prepara- possible because of their enormous ef- Kelson, D., Illingworth, G. D., 1999, ApJL, tion. forts. 520, L95. Optical Observations of Pulsars: the ESO Contribution R.P. MIGNANI1, P.A. CARAVEO 2 and G.F. BIGNAMI3 1ST-ECF, [email protected]; 2IFC-CNR, [email protected]; 3ASI [email protected] Introduction matic gamma-rays source Geminga, and ESO telescopes gave to the not yet recognised as an X/gamma-ray European astronomers the chance to Our knowledge of the optical emis- pulsar, was proposed. -
SXP 1062, a Young Be X-Ray Binary Pulsar with Long Spin Period⋆
A&A 537, L1 (2012) Astronomy DOI: 10.1051/0004-6361/201118369 & c ESO 2012 Astrophysics Letter to the Editor SXP 1062, a young Be X-ray binary pulsar with long spin period Implications for the neutron star birth spin F. Haberl1, R. Sturm1, M. D. Filipovic´2,W.Pietsch1, and E. J. Crawford2 1 Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany e-mail: [email protected] 2 University of Western Sydney, Locked Bag 1797, Penrith South DC, NSW1797, Australia Received 31 October 2011 / Accepted 1 December 2011 ABSTRACT Context. The Small Magellanic Cloud (SMC) is ideally suited to investigating the recent star formation history from X-ray source population studies. It harbours a large number of Be/X-ray binaries (Be stars with an accreting neutron star as companion), and the supernova remnants can be easily resolved with imaging X-ray instruments. Aims. We search for new supernova remnants in the SMC and in particular for composite remnants with a central X-ray source. Methods. We study the morphology of newly found candidate supernova remnants using radio, optical and X-ray images and inves- tigate their X-ray spectra. Results. Here we report on the discovery of the new supernova remnant around the recently discovered Be/X-ray binary pulsar CXO J012745.97−733256.5 = SXP 1062 in radio and X-ray images. The Be/X-ray binary system is found near the centre of the supernova remnant, which is located at the outer edge of the eastern wing of the SMC. The remnant is oxygen-rich, indicating that it developed from a type Ib event. -
Gravitational Waves with the SKA
Spanish SKA White Book, 2015 Font, Sintes & Sopuerta 29 Gravitational waves with the SKA Jos´eA. Font1;2, Alicia M. Sintes3, and Carlos F. Sopuerta4 1 Departamento de Astronom´ıay Astrof´ısica,Universitat de Val`encia,Dr. Moliner 50, 46100, Burjassot (Val`encia) 2 Observatori Astron`omic,Universitat de Val`encia,Catedr´aticoJos´eBeltr´an2, 46980, Paterna (Val`encia) 3 Departament de F´ısica,Universitat de les Illes Balears and Institut d'Estudis Espacials de Catalunya, Cra. Valldemossa km. 7.5, 07122 Palma de Mallorca 4 Institut de Ci`enciesde l'Espai (CSIC-IEEC), Campus UAB, Carrer de Can Magrans, 08193 Cerdanyola del Vall´es(Barcelona) Abstract Through its sensitivity, sky and frequency coverage, the SKA will be able to detect grav- itational waves { ripples in the fabric of spacetime { in the very low frequency band (10−9 − 10−7 Hz). The SKA will find and monitor multiple millisecond pulsars to iden- tify and characterize sources of gravitational radiation. About 50 years after the discovery of pulsars marked the beginning of a new era in fundamental physics, pulsars observed with the SKA have the potential to transform our understanding of gravitational physics and provide important clues about the early history of the Universe. In particular, the gravi- tational waves detected by the SKA will allow us to learn about galaxy formation and the origin and growth history of the most massive black holes in the Universe. At the same time, by analyzing the properties of the gravitational waves detected by the SKA we should be able to challenge the theory of General Relativity and constraint alternative theories of gravity, as well as to probe energies beyond the realm of the standard model of particle physics. -
Arxiv:2009.06555V3 [Astro-Ph.CO] 1 Feb 2021
KCL-PH-TH/2020-53, CERN-TH-2020-150 Cosmic String Interpretation of NANOGrav Pulsar Timing Data John Ellis,1, 2, 3, ∗ and Marek Lewicki1, 4, y 1Kings College London, Strand, London, WC2R 2LS, United Kingdom 2Theoretical Physics Department, CERN, Geneva, Switzerland 3National Institute of Chemical Physics & Biophysics, R¨avala10, 10143 Tallinn, Estonia 4Faculty of Physics, University of Warsaw ul. Pasteura 5, 02-093 Warsaw, Poland Pulsar timing data used to provide upper limits on a possible stochastic gravitational wave back- ground (SGWB). However, the NANOGrav Collaboration has recently reported strong evidence for a stochastic common-spectrum process, which we interpret as a SGWB in the framework of cosmic strings. The possible NANOGrav signal would correspond to a string tension Gµ 2 (4×10−11; 10−10) at the 68% confidence level, with a different frequency dependence from supermassive black hole mergers. The SGWB produced by cosmic strings with such values of Gµ would be beyond the reach of LIGO, but could be measured by other planned and proposed detectors such as SKA, LISA, TianQin, AION-1km, AEDGE, Einstein Telescope and Cosmic Explorer. Introduction: Stimulated by the direct discovery of for cosmic string models, discussing how experiments gravitational waves (GWs) by the LIGO and Virgo Col- could confirm or disprove such an interpretation. Upper laborations [1{8] of black holes and neutron stars at fre- limits on the SGWB are often quoted assuming a spec- 2=3 quencies f & 10 Hz, there is widespread interest in ex- trum described by a GW abundance proportional to f , periments exploring other parts of the GW spectrum.