A5033337386- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Geophysics and Gravity Measurements
- High-pressure geophysics and materials
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Geophysics and Sensor Technology
- Particle Detector Development and Performance
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Solar and Space Plasma Dynamics
- Particle Accelerators and Free-Electron Lasers
- Medical Imaging Techniques and Applications
- Dark Matter and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Calibration and Measurement Techniques
- Radiomics and Machine Learning in Medical Imaging
- Galaxies: Formation, Evolution, Phenomena
- Computational Physics and Python Applications
- Seismology and Earthquake Studies
- Advanced X-ray and CT Imaging
- Relativity and Gravitational Theory
George Washington University
2015-2024
University of Maryland, College Park
2023-2024
Joint Space Science Institute
2024
Massachusetts Institute of Technology
2023
Compact Imaging (United States)
2023
George Washington University Virginia Campus
2019
University of Florida
2008-2013
Pennsylvania State University
2001-2010
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation O. Kargaltsev, G. Pavlov; Pulsar Wind Nebulae in the Chandra Era. AIP Conf. Proc. 27 February 2008; 983 (1): 171–185. https://doi.org/10.1063/1.2900138 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Dropdown Menu input auto suggest...
The All-sky Medium Energy Gamma-ray Observatory (AMEGO) is a probe class mission concept that will provide essential contributions to multimessenger astrophysics in the late 2020s and beyond. AMEGO combines high sensitivity 200 keV 10 GeV energy range with wide field of view, good spectral resolution, polarization sensitivity. Therefore, key study astrophysical objects have unique signatures gamma-ray regime, such as neutron star mergers, supernovae, flaring active galactic nuclei....
The Advanced X-ray Imaging Satellite (AXIS) is a Probe-class concept that will build on the legacy of Chandra Observatory by providing low-background, arcsecond-resolution imaging in 0.3-10 keV band across 450 arcminute$^2$ field view, with an order magnitude improvement sensitivity. AXIS utilizes breakthroughs construction lightweight segmented optics using single-crystal silicon, and developments fabrication large-format, small-pixel, high readout rate CCD detectors good spectral...
We report on six new Chandra observations of the Geminga pulsar wind nebula (PWN). The PWN consists three distinct elongated structures - two $\approx 0.2 d_{250}$ pc long lateral tails and a segmented axial tail 0.05 length, where $d_{250}=d/(250 {\rm pc})$. photon indices power law spectra tails, $\Gamma \approx 1$, are significantly harder than those ($\Gamma 1.5$) 1.6$). There is no significant diffuse X-ray emission between -- ratio surface brightness south this sky area at least 12....
Observations of the Vela pulsar-wind nebula (PWN) with Chandra X-Ray Observatory have revealed a complex, variable PWN structure, including inner and outer arcs, jet in direction pulsar's proper motion, counterjet opposite direction, embedded diffuse nebular emission. The consists bright, 8'' long jet, between pulsar arc, dim, curved that extends up to ~100'' approximately same direction. From analysis 13 observations spread over ≈2.5 yr we found this shows particularly strong variability,...
We present extensive spectral and photometric observations of the recycled pulsar/white dwarf binary containing PSR J0437−4715, which we analyzed together with archival X-ray gamma-ray data, to obtain complete mid-infrared spectrum. first fit each part spectrum separately, then whole multi-wavelength find that optical–infrared is well by a cool white atmosphere model pure hydrogen composition. The (Teff = 3950 ± 150 K, log g 6.98 0.15, RWD (1.9 0.2) × 109 cm) fits our data remarkably for...
To examine the previously claimed fast cooling of Central Compact Object (CCO) in Cas A supernova remnant (SNR), we analyzed two Chandra observations this CCO, taken a setup minimizing instrumental spectral distortions. We fit CCO X-ray spectra from 2006 and 2012 with hydrogen carbon neutron star atmosphere models. The temperature flux changes 5.5 yr between epochs depend on adopted constraints fitting parameters uncertainties effective area calibrations. If allow change equivalent emitting...
TeV J2032+4130 was the first unidentified source discovered at very high energies (VHE; E $>$ 100 GeV), with no obvious counterpart in any other wavelength. It is also extended to be observed VHE gamma rays. Following its discovery, intensive observational campaigns have been carried out all wavelengths order understand nature of object, which met limited success. We report here on a deep observation J2032+4130, based 48.2 hours data taken from 2009 2012 by VERITAS (Very Energetic Radiation...
ABSTRACT We report on the analysis of two deep XMM-Newton observations magnetar Swift J1834.9−0846 and its surrounding extended emission taken in 2014 March October, 2.5 3.1 yr after source went into outburst. The is only weakly detected first observation, with an absorption-corrected flux <?CDATA ${F}_{0.5-10\mathrm{keV}}\approx 4\times {10}^{-14}$?> erg s −1 cm −2 a $3\sigma $?> upper limit during second observation about 3 × 10 −14 . This level more than orders magnitude lower measured at...
We present very high energy (VHE) imaging of MGRO J2019+37 obtained with the VERITAS observatory. The bright extended ($\sim2^{\circ}$) unidentified Milagro source is located towards rich star formation region Cygnus-X. resolved into two sources. faint point-like VER J2016+371 overlaps CTB 87, a filled-center remnant (SNR) no evidence supernova shell at time. Its spectrum well fit in $0.65 - 10$ TeV range by power-law model photon index $2.3\pm0.4$. J2019+368 ($\sim1^{\circ}$) source, that...
We observed PSR J0437-4715 with the FUV-MAMA detector of Space Telescope Imaging Spectrometer (STIS) to measure pulsar's spectrum and pulsations. For first time, UV emission from a millisecond pulsar has been detected. The measured flux, (2.0 ± 0.2) × 10-15 ergs s-1 cm-2 in 1150-1700 Å range, corresponds luminosity LFUV = (4.7 0.5) 1027 s-1, for distance 140 pc negligible interstellar extinction. shape suggests thermal neutron star surface surprisingly high temperature about 1 105 K, above...
Chandra and XMM-Newton resolved extremely long tails behind two middle-aged pulsars, J1509-5850 J1740+1000. The tail of PSR is discernible up to 5.6' from the pulsar (6.5 pc at a distance 4 kpc), with flux 2*10^{-13} erg s^{-1} cm^{-2} in 0.5-8 keV. spectrum fits an absorbed power-law (PL) model photon index 2.3\pm0.2, corresponding keV luminosity 1*10^{33} ergs s^{-1}, for n_H= 2.1*10^{22} cm^{-2}. J1740+1000 firmly detected 5' (2 1.4 kpc distance), 6*10^{-14} 0.4-10 PL fit yields 1.4-1.5...
We present X-ray observations of the new transient magnetar Swift J1834.9-0846, discovered with BAT on 2011 August 7. The data were obtained Swift, RXTE, CXO, and XMM-Newton both before after outburst. Timing analysis reveals singe peak pulsations a period 2.4823 s an unusually high pulsed fraction, 85+/-10%. Using RXTE CXO data, we estimated derivative, dot{P}=8\times 10^{-12} s/s, confirmed magnetic field source, B=1.4\times 10^{14} G. decay persistent flux, spanning 48 days, is consistent...
The rapid increase in serendipitous X-ray source detections requires the development of novel approaches to efficiently explore nature sources. If even a fraction these sources could be reliably classified, it would enable population studies for various astrophysical types on much larger scale than currently possible. Classification large numbers from multiple classes characterized by properties (features) must done automatically and supervised machine learning (ML) seems provide only...
Far-ultraviolet (FUV) observations of pulsars allow us to measure surface temperatures neutron stars and study their thermal evolution. Some can exhibit FUV bow-shock nebulae (BSNe), providing an additional tool for probing the interstellar medium studying pulsar's properties. The nearby middle-aged gamma-ray pulsar J1741--2054 its wind nebula (PWN) have been studied in X-rays, BSN has investigated Balmer lines, but they never observed FUV. To further magnetospheric emission from PSR...
The observations of the pulsar-wind nebula (PWN) around Vela pulsar with Advanced CCD Imaging Spectrometer aboard Chandra X-ray Observatory, taken on 2000 April 30 and November 30, reveal its complex morphology reminiscent that Crab PWN. Comparison two shows changes up to 30% in surface brightness PWN features. Some elements show appreciable shifts, a few arcseconds (about 10^{16} cm), and/or spectral changes. To elucidate nature observed variations, further monitoring is needed.
We observed the γ-ray pulsar Geminga with FUV-MAMA and NUV-MAMA detectors of Space Telescope Imaging Spectrometer to measure Geminga's spectrum pulsations in ultraviolet. The slope far-ultraviolet (FUV) is close that a Rayleigh-Jeans spectrum, suggesting FUV radiation dominated by thermal emission from neutron star (NS) surface. measured flux, FFUV = (3.7 ± 0.2) × 10-15 ergs cm-2 s-1 1155-1702 Å band, corresponds brightness temperature TRJ ≈ (0.3-0.4)(d200/R13)2 MK, depending on interstellar...
Taking advantage of the high sensitivity Chandra Advanced CCD Imaging Spectrometer, we have conducted a snap-shot survey pulsars previously undetected in X-rays. We detected 12 and established deep flux limits for 11 pulsars. Using these new results, revisit relationship between X-ray luminosity, L_psr_x, spin-down power, Edot. find that obtained further increase extremely large spread non-thermal efficiencies, eta_psr_x=L_psr_x/Edot, with some them being now below 1e-5. Such cannot be...
We review multiwavelength properties of pulsar wind nebulae (PWNe) created by supersonically moving pulsars and the effects motion on PWN morphologies ambient medium. Supersonic (SPWNe) are characterized bow-shaped shocks around and/or cometary tails filled with shocked wind. In past several years significant advances in SPWN studies have been made deep observations Chandra XMM-Newton X-ray Observatories as well Hubble Space Telescope. particular, these revealed very diverse vicinity,...