A5030057699- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Cosmology and Gravitation Theories
- Geophysics and Sensor Technology
- Astronomy and Astrophysical Research
- Advanced Frequency and Time Standards
- Radio Astronomy Observations and Technology
- High-pressure geophysics and materials
- Astro and Planetary Science
- Seismic Waves and Analysis
- Atomic and Subatomic Physics Research
- Stellar, planetary, and galactic studies
- Particle Accelerators and Free-Electron Lasers
- Statistical and numerical algorithms
- Cold Atom Physics and Bose-Einstein Condensates
- SAS software applications and methods
- Solar and Space Plasma Dynamics
- GNSS positioning and interference
- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Particle Detector Development and Performance
Texas Tech University
2016-2025
George Washington University
2013-2015
California Institute of Technology
2010-2014
Corcoran College of Art and Design
2013
LIGO Scientific Collaboration
2013
Istituto Nazionale di Fisica Nucleare, Sezione di Roma I
2006-2012
National Institute for Astrophysics
2005-2011
Sapienza University of Rome
2005-2011
University of Warsaw
2010
Université de Rennes
2010
Gravitational waves have been detected from a binary neutron star merger event, GW170817. The detection of electromagnetic radiation the same source has shown that occurred in outskirts galaxy NGC 4993, at distance 40 megaparsecs Earth. We report counterpart radio appears 16 days after allowing us to diagnose energetics and environment merger. observed emission can be explained by either collimated ultra-relativistic jet viewed off-axis, or cocoon mildly relativistic ejecta. Within 100...
Merging neutron stars offer an exquisite laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of electromagnetic counterpart EM170817 to gravitational waves (GW170817) detected from merging stars. By synthesizing a panchromatic dataset, we demonstrate that are long-sought production site forging heavy elements by r-process nucleosynthesis. The weak gamma-rays seen dissimilar classical short gamma-ray bursts with...
This paper presents a complete description of Virgo, the French-Italian gravitational wave detector. The detector, built at Cascina, near Pisa (Italy), is very large Michelson interferometer, with 3 km-long arms. In this paper, following presentation physics requirements, leading to specifications for construction detailed all its different elements given. These include civil engineering infrastructures, huge ultra-high vacuum (UHV) chamber (about 6000 cubic metres), optical components,...
The advanced interferometer network will herald a new era in observational astronomy. There is very strong science case to go beyond the detector and build detectors that operate frequency range from 1 Hz-10 kHz, with sensitivity factor ten better amplitude. Such be able probe of topics nuclear physics, astronomy, cosmology fundamental providing insights into many unsolved problems these areas.
During the second observing run of Laser Interferometer gravitational- wave Observatory (LIGO) and Virgo Interferometer, a gravitational-wave signal consistent with binary neutron star coalescence was detected on 2017 August 17th (GW170817), quickly followed by coincident short gamma-ray burst trigger Fermi satellite. The Distance Less Than 40 (DLT40) Mpc supernova search performed pointed follow-up observations sample galaxies regularly monitored survey which fell within combined LIGO+Virgo...
We present multiwavelength observations of the afterglow GRB 130427A, brightest (in total fluence) gamma-ray burst (GRB) past 29 yr. Optical spectroscopy from Gemini-North reveals redshift to be z = 0.340, indicating that its unprecedented brightness is primarily result relatively close proximity Earth; intrinsic luminosities both and are not extreme in comparison other bright GRBs. a large suite spanning 300 s 130 days after demonstrate shows simple, smooth evolution at all frequencies,...
The Virgo detector has now finished its first science run; a mode duty cycle of more than 80% and 4.5 Mpc horizon distance for binary neutron star inspiral sources were achieved. Commissioning breaks organized during the run which permitted improvement sensitivity robustness interferometer against environmental perturbations like bad weather earthquakes. post-run commissioning phase started, with goal preparing next upgrade step detector, Virgo+.
We describe the present state and future evolution of Virgo gravitational wave detector, realized by Collaboration at European Gravitational Observatory, in Cascina near Pisa Italy. summarize basic principles operation design features detector. sensitivity due to a series intermediate upgrades called Virgo+ which is being completed this year includes new monolithic suspensions. scientific potential Finally we discuss plans for second generation Advanced Virgo, introducing its features,...
The existence of a shallow decay phase in the early X-ray afterglows gamma-ray bursts is common feature. Here we investigate possibility that this connected to formation highly magnetized millisecond pulsar, pumping energy into fireball on timescales longer than prompt emission. In scenario, nascent neutron star could undergo secular bar-mode instability, leading gravitational wave losses which would affect spin-down. case, nearby with isotropic energies order 1050 ergs produce detectable...
The optical and optical/near-infrared pseudo-bolometric light curves of 85 stripped-envelope supernovae (SNe) are constructed using a consistent method standard cosmology. analysed to derive temporal characteristics peak luminosity $L_{\mathrm{p}}$, enabling the construction function. Subsequently, mass $^{56}$Ni synthesised in explosion, along with ratio ejecta kinetic energy, found. Analysis shows that host-galaxy extinction is an important factor accurately determining values as it...
Abstract We present new 0.6–10 GHz observations of the binary neutron star merger GW170817 covering period up to 300 days post-merger, taken with upgraded Karl G. Jansky Very Large Array, Australia Telescope Compact Giant Metrewave Radio and MeerKAT telescope. use these data precisely characterize decay phase late-time radio light curve. find that temporal is consistent a power-law slope t −2.2 , transition between rise relatively sharp. Such cannot be produced by quasi-isotropic...
Abstract We report our identification of the optical afterglow and host galaxy short-duration gamma-ray burst sGRB 160821B. The spectroscopic redshift is z = 0.162, making it one lowest bursts (sGRBs) identified by Swift . Our intensive follow-up campaign using a range ground-based facilities as well Hubble Space Telescope , XMM-Newton shows evidence for late-time excess near-infrared emission in addition to complex afterglow. light curve at X-ray frequencies reveals narrow jet, <?CDATA...
Recent searches of gravitational-wave (GW) data raise the question what maximum GW energies could be emitted during gamma-ray flares highly magnetized neutron stars (magnetars). The highest (\sim 10^{49} erg) predicted so far come from a model [K. Ioka, Mon. Not. Roy. Astron. Soc. 327, 639 (2001)] in which internal magnetic field magnetar experiences global reconfiguration, changing hydromagnetic equilibrium structure star and tapping gravitational potential energy without energy. largest...
We present 2-9 GHz radio observations of GW170817 covering the period 125-200 days post-merger, taken with Australia Telescope Compact Array and Karl G. Jansky Very Large Array. Our demonstrate that afterglow peaked at $149\pm2$ post-merger is now declining in flux density. see no evidence for evolution radio-only spectral index, which remains consistent optically-thin synchrotron emission connecting radio, optical, X-ray regimes. The peak implies a total energy synchrotron-emitting...
Abstract One of the open questions following discovery GW170817 is whether neutron star (NS) mergers are only astrophysical sites capable producing r -process elements. Simulations have shown that 0.01–0.1 M ⊙ material could be generated in outflows originating from accretion disk surrounding rapidly rotating black hole forms as a remnant to both NS and collapsing massive stars associated with long-duration gamma-ray bursts (collapsars). The hallmark signature nucleosynthesis binary merger...
The Virgo collaboration has just concluded its first long science run (VSR1). In these four months the detector achieved a good duty cycle, larger than 80%, and an average horizon distance for binary neutron star system sources of about 4 Mpc. An intense commissioning activity was resumed after complete to further increase performances prepare Virgo+ upgrades. during last achievements are briefly discussed here.
We present the discovery, classification, and extensive panchromatic (from radio to X-ray) follow-up observations of PTF11qcj, a supernova (SN) discovered by Palomar Transient Factory (PTF). Our with Karl G. Jansky Very Large Array show that this event is radio-loud: PTF11qcj reached peak luminosity comparable famous gamma-ray-burst-associated SN 1998bw (L5 GHz ≈ 1029 erg s−1 Hz−1). also detected in X-rays Chandra Observatory, infrared band Spitzer. multi-wavelength analysis probes...
Many of the astrophysical sources and violent phenomena observed in our Universe are potential emitters gravitational waves high-energy cosmic radiation, including photons, hadrons, presumably also neutrinos. Both (GW) neutrinos (HEN) messengers that may escape much denser media than photons. They travel unaffected over cosmological distances, carrying information from inner regions engines which they emitted (and photons charged rays cannot reach us). For same reasons, such could reveal...
We investigate the light-curve properties of a sample 26 spectroscopically confirmed hydrogen-poor superluminous supernovae (SLSNe-I) in Palomar Transient Factory (PTF) survey. These events are brighter than SNe Ib/c and Ic-BL, on average, by about 4 2~mag, respectively. The peak absolute magnitudes SLSNe-I rest-frame $g$ band span $-22\lesssim M_g \lesssim-20$~mag, these peaks not powered radioactive $^{56}$Ni, unless strong asymmetries at play. rise timescales longer for SLSNe normal Ib/c,...
Type Ic supernovae (SNe Ic) arise from the core-collapse of H (and He) poor stars, which could be either single WR stars or lower-mass stripped their envelope by a companion. Their light curves are radioactively powered and usually show fast rise to peak ($\sim$10-15 d), without any early (first few days) emission bumps (with exception broad-lined SNe as sometimes seen for other types stripped-envelope (e.g., IIb SN 1993J Ib 2008D). We have studied iPTF15dtg, spectroscopically normal with an...
Abstract Supernova (SN) 2018cow is an optical transient detected in the galaxy CGCG 137–068. It has been classified as SN due to various characteristics its spectra. The also a bright X-ray source. We present results of analysis ∼62 ks observations taken with Neil Gehrels Swift Observatory over 27 d. found variable behaviour 0.3–10 keV light curve 2018cow, variability time-scales days. observed could be interaction between ejecta and non-uniform circumstellar medium, perhaps related previous...