I. Neri

Publications (76)179.87 Total impact

• Article: Hair in newborns and infants: clinical and dermoscopic evaluation of 45 cases.

  I Neri, V Piccolo, G Cocchi, M Starace, A Patrizi, E Dika, B M Piraccini
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  ABSTRACT: BACKGROUND: literature still lacks comprehensive assessments on the features of neonatal hair and scalp characteristics. MATERIAL AND METHODS: 45 newborns were recruited for this study. For each patient, data regarding sex, age at consultation, delivery method, gestational age, and maternal age at delivery were collected. A clinical score of hair density was created by investigators in order to divide the neonates in 2 groups: group 1 included neonates with poor and slightly poor hair density, group 2 included neonates with quite good and good hair density. Each patient underwent scalp videodermatoscopy (Fotofinder Trichoscan(®) ). RESULTS: Based on their clinical score, 15 newborns had good hair density, while 30 had poor hair density. Among the parameters evaluated by the investigators, only weight at birth significantly correlated with neonatal hair density. Two neonates presented a frontal-temporal pattern of hair loss. Videodermatoscopy showed that 9 neonates, all in the poor density group, had a particular hair shaft dermoscopy feature, characterized by the presence of widespread thin hair. DISCUSSION: On the basis of the results obtained from our study, we propose a new classification of transient neonatal hair loss. We have found 2 different hair types: 'Neonatal type', rarely observed, that appears in first 4 weeks of life with a frontal-temporal pattern; and 'Classic type', more frequently observed, appearing at 8-12 weeks of life with a predominant occipital pattern. This article is protected by copyright. All rights reserved.
  British Journal of Dermatology 06/2013; · 3.67 Impact Factor
• Article: Parameter estimation for compact binary coalescence signals with the first generation gravitational-wave detector network

  the LIGO Scientific Collaboration, the Virgo Collaboration, J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, [......], M. Yvert, A. Zadrożny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: Compact binary systems with neutron stars or black holes are one of the most promising sources for ground-based gravitational wave detectors. Gravitational radiation encodes rich information about source physics; thus parameter estimation and model selection are crucial analysis steps for any detection candidate events. Detailed models of the anticipated waveforms enable inference on several parameters, such as component masses, spins, sky location and distance that are essential for new astrophysical studies of these sources. However, accurate measurements of these parameters and discrimination of models describing the underlying physics are complicated by artifacts in the data, uncertainties in the waveform models and in the calibration of the detectors. Here we report such measurements on a selection of simulated signals added either in hardware or software to the data collected by the two LIGO instruments and the Virgo detector during their most recent joint science run, including a "blind injection" where the signal was not initially revealed to the collaboration. We exemplify the ability to extract information about the source physics on signals that cover the neutron star and black hole parameter space over the individual mass range 1 Msun - 25 Msun and the full range of spin parameters. The cases reported in this study provide a snap-shot of the status of parameter estimation in preparation for the operation of advanced detectors.
  04/2013;
• Source

  Available from: Luca Gammaitoni

  Article: Universal and reconfigurable logic gates in a compact three-terminal resonant tunneling diode

  L. Worschech, F. Hartmann, T. Y. Kim, S Höfling, M. Kamp, A. Forchel, Jouni Ahopelto, I. Neri, A. Dari, L. Gammaitoni
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  ABSTRACT: Applied Physics Letters Vol.96 Nr.4, Article number 042112
  Applied Physics Letters 12/2012; 96:042112. · 3.84 Impact Factor
• Article: Search for Gravitational Waves from Binary Black Hole Inspiral, Merger and Ringdown in LIGO-Virgo Data from 2009-2010

  The LIGO Scientific Collaboration, the Virgo Collaboration, J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, [......], M. Yvert, A. Zadrozny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: We report a search for gravitational waves from the inspiral, merger and ringdown of binary black holes (BBH) with total mass between 25 and 100 solar masses, in data taken at the LIGO and Virgo observatories between July 7, 2009 and October 20, 2010. The maximum sensitive distance of the detectors over this period for a (20,20) Msun coalescence was 300 Mpc. No gravitational wave signals were found. We thus report upper limits on the astrophysical coalescence rates of BBH as a function of the component masses for non-spinning components, and also evaluate the dependence of the search sensitivity on component spins aligned with the orbital angular momentum. We find an upper limit at 90% confidence on the coalescence rate of BBH with non-spinning components of mass between 19 and 28 Msun of 3.3 \times 10^-7 mergers /Mpc^3 /yr.
  09/2012;
• Article: Persistent Agmination of Lymphomatoid Papulosis: An Ongoing Debate.

  A Pileri, F Bacci, I Neri, S Ciabatti, V Stefoni, P L Zinzani, A Patrizi
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  ABSTRACT: Background: Persistent agmination of lymphomatoid papulosis (PALP) has been a matter of controversy in the literature, some authors suggesting that it represents composite lymphoma, others localized lymphomatoid papulosis (LyP). Patient and Methods: A 64-year-old man was referred to our outpatient center complaining of papular eruptions lasting 3 years. At physical examination, he showed papulonodular lesions on the trunk and extremities. Some patches on the trunk and upper arms were also observed. Both types of lesion were biopsied and studied on histological, immunohistochemical and molecular grounds. Results: The nodular lesion revealed the classical features of LyP type A, while the patch was characterized by the presence of a superficial and deep infiltrate with perivascular and interstitial location, consisting of mature lymphocytes admixed with plasma cells and large atypical cells that became more numerous beneath the epidermis. On immunohistochemistry the two lesions presented the same profile. Conclusion: Our case suggests that PALP does not correspond to localized LyP, as it can involve different skin areas since its presentation. Furthermore it rules out the possibility that PALP is a composite lymphoma. In fact, the same cytological and phenotypic characteristics were detected in all samples, including those taken from patchy areas.
  Dermatology 09/2012; · 2.05 Impact Factor
• Conference Proceeding: HYBRID AUTONOMOUS TRANSCEIVERS

  F Orfei, R Mincigrucci, I Neri, F Travasso, H Vocca, L Gammaitoni
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  ABSTRACT: A small photocell and a non-linear vibration energy harvester have been used to power a low power wireless transceiver device. The device, a technology demonstrator, is self-powered and works without any battery on board. It is able to transmit at few meters distance data such as the temperature and the power supply voltage values in the 2,4 GHz ISM band every 10 seconds.
  European DSP in Education and Research Conference, Amsterdam; 09/2012
• Source

  Available from: Reinhard Prix

  Article: Einstein@Home all-sky search for periodic gravitational waves in LIGO S5 data

  J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, T. Adams, [......], A. Zadrożny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig, D. P. Anderson
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  ABSTRACT: This paper presents results of an all-sky searches for periodic gravitational waves in the frequency range [50, 1190] Hz and with frequency derivative ranges of [-2 x 10^-9, 1.1 x 10^-10] Hz/s for the fifth LIGO science run (S5). The novelty of the search lies in the use of a non-coherent technique based on the Hough-transform to combine the information from coherent searches on timescales of about one day. Because these searches are very computationally intensive, they have been deployed on the Einstein@Home distributed computing project infrastructure. The search presented here is about a factor 3 more sensitive than the previous Einstein@Home search in early S5 LIGO data. The post-processing has left us with eight surviving candidates. We show that deeper follow-up studies rule each of them out. Hence, since no statistically significant gravitational wave signals have been detected, we report upper limits on the intrinsic gravitational wave amplitude h0. For example, in the 0.5 Hz-wide band at 152.5 Hz, we can exclude the presence of signals with h0 greater than 7.6 x 10^-25 with a 90% confidence level.
  07/2012;
• Article: Spectra of sparse non-hermitian random matrices: an analytical solution.

  I Neri, F L Metz
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  ABSTRACT: We present the exact analytical expression for the spectrum of a sparse non-hermitian random matrix ensemble, generalizing two standard results in random-matrix theory: this analytical expression constitutes a non-hermitian version of the Kesten-McKay measure as well as a sparse realization of Girko's elliptic law. Our exact result opens new perspectives in the study of several physical problems modelled on sparse random graphs, which are locally treelike. In this context, we show analytically that the convergence rate of a transport process on a very sparse graph depends in a nonmonotonic way upon the degree of symmetry of the graph edges.
  Physical Review Letters 07/2012; 109(3):030602. · 7.37 Impact Factor
• Article: Xanthelasma palpebrarum: a new adverse reaction to intradermal fillers?

  C D'Acunto, M Pazzaglia, B Raone, C Misciali, L Badiali, I Neri, A Patrizi
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  ABSTRACT: Over the last years, many different techniques have been utilized to treat age related wrinkles. We describe here two patients with a new type of filler adverse reaction, xanthelasma-like, that appeared after the infiltration of hyaluronic acid in the superficial dermis of the lower eyelids. Case 1 A 49-year-old caucasian woman was stated to us for a lesion that resembled a xanthelasma palpebrarum on her right lower eyelid. The patient referred that, one year before, a filler had been infiltrated in the same area to reduce the wrinkles.
  British Journal of Dermatology 07/2012; · 3.67 Impact Factor
• Article: A First Search for coincident Gravitational Waves and High Energy Neutrinos using LIGO, Virgo and ANTARES data from 2007

  The ANTARES Collaboration, the LIGO Scientific Collaboration, the Virgo Collaboration, S. Adrián-Martínez, I. Al Samarai, A. Albert, M. André, M. Anghinolfi, G. Anton, S. Anvar, [......], M. Yvert, A. Zadroźny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place limits on the density of joint high energy neutrino - gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events.
  05/2012;
• Article: Search for gravitational waves associated with gamma-ray bursts during LIGO science run 6 and Virgo science runs 2 and 3

  The LIGO Scientific Collaboration, Virgo Collaboration, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, [......], N. Zotov, M. E. Zucker, J. Zweizig, M. S. Briggs, V. Connaughton, K. C. Hurley, P. A. Jenke, A. von Kienlin, A. Rau, X. -L. Zhang
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  ABSTRACT: We present the results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs. We perform two distinct searches: a modeled search for coalescences of either two neutron stars or a neutron star and black hole; and a search for generic, unmodeled gravitational-wave bursts. We find no evidence for gravitational-wave counterparts, either with any individual GRB in this sample or with the population as a whole. For all GRBs we place lower bounds on the distance to the progenitor, under the optimistic assumption of a gravitational-wave emission energy of 10^-2 M c^2 at 150 Hz, with a median limit of 17 Mpc. For short hard GRBs we place exclusion distances on binary neutron star and neutron star-black hole progenitors, using astrophysically motivated priors on the source parameters, with median values of 16 Mpc and 28 Mpc respectively. These distance limits, while significantly larger than for a search that is not aided by GRB satellite observations, are not large enough to expect a coincidence with a GRB. However, projecting these exclusions to the sensitivities of Advanced LIGO and Virgo, which should begin operation in 2015, we find that the detection of gravitational waves associated with GRBs will become quite possible.
  05/2012;
• Article: Virgo: a laser interferometer to detect gravitational waves

  T Accadia, F Acernese, M Alshourbagy, P Amico, F Antonucci, S Aoudia, N Arnaud, C Arnault, K G Arun, P Astone, [......], J -Y Vinet, S Vilalte, S Vitale, H Vocca, R L Ward, M Was, K Yamamoto, M Yvert, J -P Zendri, Z Zhang
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  ABSTRACT: This paper presents a complete description of Virgo, the French-Italian gravitational wave detector. The detector, built at Cascina, near Pisa (Italy), is a very large Michelson interferometer, with 3 km-long arms. In this paper, following a presentation of the physics requirements, leading to the specifications for the construction of the detector, a detailed description of all its different elements is given. These include civil engineering infrastructures, a huge ultra-high vacuum (UHV) chamber (about 6000 cubic metres), all of the optical components, including high quality mirrors and their seismic isolating suspensions, all of the electronics required to control the interferometer and for signal detection. The expected performances of these different elements are given, leading to an overall sensitivity curve as a function of the incoming gravitational wave frequency. This description represents the detector as built and used in the first data-taking runs. Improvements in different parts have been and continue to be performed, leading to better sensitivities. These will be detailed in a forthcoming paper.
  Journal of Instrumentation 03/2012; 7(03):P03012. · 1.87 Impact Factor
• Article: The characterization of Virgo data and its impact on gravitational-wave searches

  J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, T. Adams, [......], M. Yvert, A. Zadrożny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: Between 2007 and 2010 Virgo collected data in coincidence with the LIGO and GEO gravitational-wave (GW) detectors. These data have been searched for GWs emitted by cataclysmic phenomena in the universe, by non-axisymmetric rotating neutron stars or from a stochastic background in the frequency band of the detectors. The sensitivity of GW searches is limited by noise produced by the detector or its environment. It is therefore crucial to characterize the various noise sources in a GW detector. This paper reviews the Virgo detector noise sources, noise propagation, and conversion mechanisms which were identified in the three first Virgo observing runs. In many cases, these investigations allowed us to mitigate noise sources in the detector, or to selectively flag noise events and discard them from the data. We present examples from the joint LIGO-GEO-Virgo GW searches to show how well noise transients and narrow spectral lines have been identified and excluded from the Virgo data. We also discuss how detector characterization can improve the astrophysical reach of gravitational-wave searches.
  03/2012;
• Article: Publisher's Note: Search for gravitational waves from compact binary coalescence in LIGO and Virgo data from S5 and VSR1 (vol 82, 102001, 2010)

  J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, P. Ajith, B. Allen, [......], S. Yoshida, P. P. Yu, M. Yvert, M. Zanolin, L. Zhang, Z. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: Abadie, J. Abbott, B. P. Abbott, R. Abernathy, M. Accadia, T. Acernese, F. Adams, C. Adhikari, R. Ajith, P. Allen, B. Allen, G. Ceron, E. Amador Amin, R. S. Anderson, S. B. Anderson, W. G. Antonucci, F. Arain, M. A. Araya, M. Aronsson, M. Arun, K. G. Aso, Y. Aston, S. Astone, P. Atkinson, D. E. Aufmuth, P. Aulbert, C. Babak, S. Baker, P. Ballardin, G. Ballinger, T. Ballmer, S. Barker, D. Barnum, S. Barone, F. Barr, B. Barriga, P. Barsotti, L. Barsuglia, M. Barton, M. A. Bartos, I. Bassiri, R. Bastarrika, M. Bauchrowitz, J. Bauer, Th. S. Behnke, B. Beker, M. G. Belletoile, A. Benacquista, M. Bertolini, A. Betzwieser, J. Beveridge, N. Beyersdorf, P. T. Bigotta, S. Bilenko, I. A. Billingsley, G. Birch, J. Birindelli, S. Biswas, R. Bitossi, M. Bizouard, M. A. Black, E. Blackburn, J. K. Blackburn, L. Blair, D. Bland, B. Blom, M. Boccara, C. Bock, O. Bodiya, T. P. Bondarescu, R. Bondu, F. Bonelli, L. Bonnand, R. Bork, R. Born, M. Bose, S. Bosi, L. Bouhou, B. Boyle, M. Braccini, S. Bradaschia, C. Brady, P. R.
  Physical Review D 01/2012; 85. · 4.56 Impact Factor
• Article: Publisher's Note: Search for gravitational waves from compact binary coalescence in LIGO and Virgo data from S5 and VSR1 (vol 82, 102001, 2010)

  J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, P. Ajith, B. Allen, [......], S. Yoshida, P. P. Yu, M. Yvert, M. Zanolin, L. Zhang, Z. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: Abadie, J. Abbott, B. P. Abbott, R. Abernathy, M. Accadia, T. Acernese, F. Adams, C. Adhikari, R. Ajith, P. Allen, B. Allen, G. Ceron, E. Amador Amin, R. S. Anderson, S. B. Anderson, W. G. Antonucci, F. Arain, M. A. Araya, M. Aronsson, M. Arun, K. G. Aso, Y. Aston, S. Astone, P. Atkinson, D. E. Aufmuth, P. Aulbert, C. Babak, S. Baker, P. Ballardin, G. Ballinger, T. Ballmer, S. Barker, D. Barnum, S. Barone, F. Barr, B. Barriga, P. Barsotti, L. Barsuglia, M. Barton, M. A. Bartos, I. Bassiri, R. Bastarrika, M. Bauchrowitz, J. Bauer, Th. S. Behnke, B. Beker, M. G. Belletoile, A. Benacquista, M. Bertolini, A. Betzwieser, J. Beveridge, N. Beyersdorf, P. T. Bigotta, S. Bilenko, I. A. Billingsley, G. Birch, J. Birindelli, S. Biswas, R. Bitossi, M. Bizouard, M. A. Black, E. Blackburn, J. K. Blackburn, L. Blair, D. Bland, B. Blom, M. Boccara, C. Bock, O. Bodiya, T. P. Bondarescu, R. Bondu, F. Bonelli, L. Bonnand, R. Bork, R. Born, M. Bose, S. Bosi, L. Bouhou, B. Boyle, M. Braccini, S. Bradaschia, C. Brady, P. R.
  Physical Review D 01/2012; 85. · 4.56 Impact Factor
• Article: Publisher's Note: Search for gravitational waves from binary black hole inspiral, merger, and ringdown (vol 83, 122005, 2011)

  J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, P. Ajith, B. Allen, [......], S. Yoshida, P. Yu, M. Yvert, M. Zanolin, L. Zhang, Z. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: Abadie, J. Abbott, B. P. Abbott, R. Abernathy, M. Accadia, T. Acernese, F. Adams, C. Adhikari, R. Ajith, P. Allen, B. Allen, G. S. Ceron, E. Amador Amin, R. S. Anderson, S. B. Anderson, W. G. Antonucci, F. Arain, M. A. Araya, M. C. Aronsson, M. Aso, Y. Aston, S. M. Astone, P. Atkinson, D. Aufmuth, P. Aulbert, C. Babak, S. Baker, P. Ballardin, G. Ballinger, T. Ballmer, S. Barker, D. Barnum, S. Barone, F. Barr, B. Barriga, P. Barsotti, L. Barsuglia, M. Barton, M. A. Bartos, I. Bassiri, R. Bastarrika, M. Bauchrowitz, J. Bauer, Th. S. Behnke, B. Beker, M. G. Belletoile, A. Benacquista, M. Bertolini, A. Betzwieser, J. Beveridge, N. Beyersdorf, P. T. Bilenko, I. A. Billingsley, G. Birch, J. Birindelli, S. Biswas, R. Bitossi, M. Bizouard, M. A. Black, E. Blackburn, J. K. Blackburn, L. Blair, D. Bland, B. Blom, M. Boccara, C. Bock, O. Bodiya, T. P. Bondarescu, R. Bondu, F. Bonelli, L. Bonnand, R. Bork, R. Born, M. Boschi, V. Bose, S. Bosi, L. Bouhou, B. Boyle, M. Braccini, S. Bradaschia, C. Brady, P. R. Bragin
  Physical Review D 01/2012; 85. · 4.56 Impact Factor
• Source

  Available from: Giancarlo Cella

  Article: Directional limits on persistent gravitational waves using LIGO S5 science data.

  J Abadie, B P Abbott, R Abbott, M Abernathy, T Accadia, F Acernese, C Adams, R Adhikari, P Ajith, B Allen, [......], S Yoshida, P Yu, M Yvert, M Zanolin, L Zhang, Z Zhang, C Zhao, N Zotov, M E Zucker, J Zweizig
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  ABSTRACT: The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2-20×10(-50)  strain(2) Hz(-1) and 5-35×10(-49)  strain(2) Hz(-1) sr(-1) for pointlike and extended sources, respectively. The latter result is the first of its kind. We also set 90% C.L. limits on the narrow-band root-mean-square GW strain from interesting targets including Sco X-1, SN 1987A and the Galactic center as low as ≈7×10(-25) in the most sensitive frequency range near 160 Hz.
  Physical Review Letters 12/2011; 107(27):271102. · 7.37 Impact Factor
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  Available from: Reinhard Prix

  Article: Beating the Spin-down Limit on Gravitational Wave Emission from the Vela Pulsar

  J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, C. Affeldt, B. Allen, [......], M. Zanolin, L. Zhang, Z. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig, S. Buchner, A. Hotan, and J. Palfreyman
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  ABSTRACT: We present direct upper limits on continuous gravitational wave emission from the Vela pulsar using data from the Virgo detector's second science run. These upper limits have been obtained using three independent methods that assume the gravitational wave emission follows the radio timing. Two of the methods produce frequentist upper limits for an assumed known orientation of the star's spin axis and value of the wave polarization angle of, respectively, 1.9 × 10–24 and 2.2 × 10–24, with 95% confidence. The third method, under the same hypothesis, produces a Bayesian upper limit of 2.1 × 10^–24, with 95% degree of belief. These limits are below the indirect spin-down limit of 3.3 × 10^–24 for the Vela pulsar, defined by the energy loss rate inferred from observed decrease in Vela's spin frequency, and correspond to a limit on the star ellipticity of ~10^–3. Slightly less stringent results, but still well below the spin-down limit, are obtained assuming the star's spin axis inclination and the wave polarization angles are unknown.
  The Astrophysical Journal 08/2011; 737(2):93. · 6.02 Impact Factor
• Article: Search for Gravitational Wave Bursts from Six Magnetars

  J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, C. Affeldt, B. Allen, [......], H. A. Krimm, L. Lin, I. Mitrofanov, M. Ohno, V. D. Pal'shin, A. Rau, A. Sanin, M. S. Tashiro, Y. Terada, and K. Yamaoka
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  ABSTRACT: Soft gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are thought to be magnetars: neutron stars powered by extreme magnetic fields. These rare objects are characterized by repeated and sometimes spectacular gamma-ray bursts. The burst mechanism might involve crustal fractures and excitation of non-radial modes which would emit gravitational waves (GWs). We present the results of a search for GW bursts from six galactic magnetars that is sensitive to neutron star f-modes, thought to be the most efficient GW emitting oscillatory modes in compact stars. One of them, SGR 0501+4516, is likely ~1 kpc from Earth, an order of magnitude closer than magnetars targeted in previous GW searches. A second, AXP 1E 1547.0–5408, gave a burst with an estimated isotropic energy >1044 erg which is comparable to the giant flares. We find no evidence of GWs associated with a sample of 1279 electromagnetic triggers from six magnetars occurring between 2006 November and 2009 June, in GW data from the LIGO, Virgo, and GEO600 detectors. Our lowest model-dependent GW emission energy upper limits for band- and time-limited white noise bursts in the detector sensitive band, and for f-mode ringdowns (at 1090 Hz), are 3.0 × 1044 d 2 1 erg and 1.4 × 1047 d 2 1 erg, respectively, where and d 0501 is the distance to SGR 0501+4516. These limits on GW emission from f-modes are an order of magnitude lower than any previous, and approach the range of electromagnetic energies seen in SGR giant flares for the first time.
  The Astrophysical Journal Letters 05/2011; 734(2):L35. · 5.53 Impact Factor
• Source

  Available from: Giancarlo Cella

  Article: Beating the spin-down limit on gravitational wave emission from the Vela pulsar

  The LIGO Scientific Collaboration, the Virgo Collaboration, J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, [......], M. Zanolin, L. Zhang, Z. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig, S. Buchner, A. Hotan, J. Palfreyman
  [show abstract] [hide abstract]
  ABSTRACT: We present direct upper limits on continuous gravitational wave emission from the Vela pulsar using data from the Virgo detector's second science run. These upper limits have been obtained using three independent methods that assume the gravitational wave emission follows the radio timing. Two of the methods produce frequentist upper limits for an assumed known orientation of the star's spin axis and value of the wave polarization angle of, respectively, $1.9\ee{-24}$ and $2.2\ee{-24}$, with 95% confidence. The third method, under the same hypothesis, produces a Bayesian upper limit of $2.1\ee{-24}$, with 95% degree of belief. These limits are below the indirect {\it spin-down limit} of $3.3\ee{-24}$ for the Vela pulsar, defined by the energy loss rate inferred from observed decrease in Vela's spin frequency, and correspond to a limit on the star ellipticity of $\sim 10^{-3}$. Slightly less stringent results, but still well below the spin-down limit, are obtained assuming the star's spin axis inclination and the wave polarization angles are unknown.
  04/2011;