Institution
Netherlands Institute for Space Research
Facility•Utrecht, Netherlands•
About: Netherlands Institute for Space Research is a facility organization based out in Utrecht, Netherlands. It is known for research contribution in the topics: Galaxy & Neutron star. The organization has 737 authors who have published 3026 publications receiving 106632 citations. The organization is also known as: SRON & Space Research Organisation Netherlands.
Topics: Galaxy, Neutron star, Stars, Spectral line, Luminosity
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University of Michigan1, Curtin University2, New York University Abu Dhabi3, Netherlands Institute for Space Research4, Harvard University5, Radboud University Nijmegen6, Massachusetts Institute of Technology7, University of Amsterdam8, Macalester College9, Centre national de la recherche scientifique10, University of Oxford11
TL;DR: In this paper, a radio and X-ray source was observed with the Karl G. Jansky Very Large Array for a total of 17.5 h at 5.3 GHz, yielding a 4.8 ± 1.4 µJy radio source at a position consistent with the binary system at a distance of 1.7 kpc.
Abstract: We report on deep, coordinated radio and X-ray observations of the black hole X-ray binary XTE J1118+480 in quiescence. The source was observed with the Karl G. Jansky Very Large Array for a total of 17.5 h at 5.3 GHz, yielding a 4.8 ± 1.4 µJy radio source at a position consistent with the binary system. At a distance of 1.7 kpc, this corresponds to an integrated radio luminosity between 4 and 8 × 10 25 ergs −1 , depending on the spectral index. This is the lowest radio luminosity measured for any accreting black hole to date. Simultaneous observations with the Chandra X-ray Telescope detected XTE J1118+480 at 1.2 × 10 −14 ergs −1 cm −2 (1–10 keV), corresponding to an Eddington ratio of ∼4 × 10 −9
159 citations
ASTRON1, Kapteyn Astronomical Institute2, Mount Stromlo Observatory3, Harvard University4, Max Planck Society5, University of Colorado Boulder6, Stockholm University7, Leiden University8, University College London9, Space Telescope Science Institute10, Netherlands Institute for Space Research11, Chalmers University of Technology12, University of Sydney13, University of Southampton14, Jacobs University Bremen15, University of Hamburg16, Radboud University Nijmegen17, University of Nice Sophia Antipolis18, Centre national de la recherche scientifique19, University of Manchester20, University of Amsterdam21, Ruhr University Bochum22, University of Oxford23, Lebedev Physical Institute24, Center for Information Technology25, Rhodes University26
TL;DR: In this article, the authors present results from observations of the NCP window using the LOFAR highband antenna (HBA) array in the frequency range 115 MHz to 163 MHz.
Abstract: The aim of the LOFAR Epoch of Reionization (EoR) project is to detect the spectral fluctuations of the redshifted HI 21cm signal. This signal is weaker by several orders of magnitude than the astrophysical foreground signals and hence, in order to achieve this, very long integrations, accurate calibration for stations and ionosphere and reliable foreground removal are essential. One of the prospective observing windows for the LOFAR EoR project will be centered at the North Celestial Pole (NCP). We present results from observations of the NCP window using the LOFAR highband antenna (HBA) array in the frequency range 115 MHz to 163 MHz. The data were obtained in April 2011 during the commissioning phase of LOFAR. We used baselines up to about 30 km. With about 3 nights, of 6 hours each, effective integration we have achieved a noise level of about 100 microJy/PSF in the NCP window. Close to the NCP, the noise level increases to about 180 microJy/PSF, mainly due to additional contamination from unsubtracted nearby sources. We estimate that in our best night, we have reached a noise level only a factor of 1.4 above the thermal limit set by the noise from our Galaxy and the receivers. Our continuum images are several times deeper than have been achieved previously using the WSRT and GMRT arrays. We derive an analytical explanation for the excess noise that we believe to be mainly due to sources at large angular separation from the NCP.
159 citations
Netherlands Institute for Space Research1, University of Amsterdam2, ASTRON3, National Centre for Radio Astrophysics4, University of Vermont5, University of Manchester6, University of Sussex7, Space Telescope Science Institute8, Centre national de la recherche scientifique9, University of Orléans10, University of Southampton11, University of Oxford12, Max Planck Society13, Lebedev Physical Institute14, Kapteyn Astronomical Institute15, Chalmers University of Technology16, University of Sydney17, University of Twente18, Harvard University19, University of Edinburgh20, Leiden University21, University of Hamburg22, Leibniz Institute for Astrophysics Potsdam23, Australian National University24, Radboud University Nijmegen25, University of Nice Sophia Antipolis26, Curtin University27, Center for Information Technology28, National Radio Astronomy Observatory29, Paris Diderot University30, Rhodes University31, University of Bonn32
TL;DR: Through simultaneous observations, synchronous switching in the radio and x-ray emission properties of pulsar PSR B0943+10 is detected, indicating rapid, global changes to the conditions in the magnetosphere, which challenge all proposed pulsar emission theories.
Abstract: Pulsars emit from low-frequency radio waves up to high-energy gamma-rays, generated anywhere from the stellar surface out to the edge of the magnetosphere. Detecting correlated mode changes across the electromagnetic spectrum is therefore key to understanding the physical relationship among the emission sites. Through simultaneous observations, we detected synchronous switching in the radio and x-ray emission properties of PSR B0943+10. When the pulsar is in a sustained radio-"bright" mode, the x-rays show only an unpulsed, nonthermal component. Conversely, when the pulsar is in a radio-"quiet" mode, the x-ray luminosity more than doubles and a 100% pulsed thermal component is observed along with the nonthermal component. This indicates rapid, global changes to the conditions in the magnetosphere, which challenge all proposed pulsar emission theories.
158 citations
Space Telescope Science Institute1, Ohio State University2, Johns Hopkins University3, Georgia State University4, University of St Andrews5, Western Michigan University6, Tel Aviv University7, Valparaiso University8, University of California, Irvine9, Pennsylvania State University10, University College London11, University of Auckland12, INAF13, University of Padua14, Ohio University15, Worcester State University16, University of Maryland, College Park17, University of Leicester18, Goddard Space Flight Center19, Spectral Sciences Incorporated20, Morehead State University21, York University22, Netherlands Institute for Space Research23, Leiden University24, University of California, Santa Barbara25, University of Chile26, University of Southampton27, Institution of Engineers, Sri Lanka28, University of Crete29, University of California, Los Angeles30, University of Amsterdam31, University of Copenhagen32, University of Arizona33, University of Missouri34, Carnegie Mellon University35
TL;DR: In this paper, the first results from a six-month long reverberation-mapping experiment in the ultraviolet based on 171 observations of the Seyfert 1 galaxy NGC 5548 with the Cosmic Origins Spectrograph on the Hubble Space Telescope are described.
Abstract: We describe the first results from a six-month long reverberation-mapping experiment in the ultraviolet based on 171 observations of the Seyfert 1 galaxy NGC 5548 with the Cosmic Origins Spectrograph on the Hubble Space Telescope. Significant correlated variability is found in the continuum and broad emission lines, with amplitudes ranging from ∼30% to a factor of two in the emission lines and a factor of three in the continuum. The variations of all the strong emission lines lag behind those of the continuum, with He II λ1640 lagging behind the continuum by ∼2.5 days and Lyα λ1215 ,C IV λ1550, and Si IV λ1400 lagging by ∼5–6 days. The relationship between the continuum and emission lines is complex. In particular, during the second half of the campaign, all emission-line lags increased by a factor of 1.3–2 and differences appear in the detailed structure of the continuum and emissionline light curves. Velocity-resolved cross-correlation analysis shows coherent structure in lag versus line of sight velocity for the emission lines; the high-velocity wings of C IV respond to continuum variations more rapidly than the line core, probably indicating higher velocity broad-line region clouds at smaller distances from the central
158 citations
University of Western Australia1, University of Edinburgh2, University of St Andrews3, Cardiff University4, Ames Research Center5, Australian Astronomical Observatory6, University of Sydney7, Monash University, Clayton campus8, University of Sussex9, University of the Western Cape10, European Space Research and Technology Centre11, Leiden University12, University of Cape Town13, University of Hamburg14, Durham University15, University of Central Lancashire16, Romanian Academy17, University of Melbourne18, Max Planck Society19, Netherlands Institute for Space Research20
TL;DR: The Lambda Adaptive Multi-Band Deblending Algorithm in R (LAMBDAR) as mentioned in this paper is a code for calculating matched aperture photometry across images that are neither pixel- nor PSF-matched, using prior aperture definitions derived from high-resolution optical imaging.
Abstract: We present the Lambda Adaptive Multi-Band Deblending Algorithm in R (LAMBDAR), a novel code for calculating matched aperture photometry across images that are neither pixel- nor PSF-matched, using prior aperture definitions derived from high resolution optical imaging. The development of this program is motivated by the desire for consistent photometry and uncertainties across large ranges of photometric imaging, for use in calculating spectral energy distributions. We describe the program, specifically key features required for robust determination of panchromatic photometry: propagation of apertures to images with arbitrary resolution, local background estimation, aperture normalisation, uncertainty determination and propagation, and object deblending. Using simulated images, we demonstrate that the program is able to recover accurate photometric measurements in both high-resolution, low-confusion, and low-resolution, high-confusion, regimes. We apply the program to the 21-band photometric dataset from the Galaxy And Mass Assembly (GAMA) Panchromatic Data Release (PDR; Driver et al. 2016), which contains imaging spanning the far-UV to the far-IR. We compare photometry derived from LAMBDAR with that presented in Driver et al. (2016), finding broad agreement between the datasets. Nonetheless, we demonstrate that the photometry from LAMBDAR is superior to that from the GAMA PDR, as determined by a reduction in the outlier rate and intrinsic scatter of colours in the LAMBDAR dataset. We similarly find a decrease in the outlier rate of stellar masses and star formation rates using LAMBDAR photometry. Finally, we note an exceptional increase in the number of UV and mid-IR sources able to be constrained, which is accompanied by a significant increase in the mid-IR colour-colour parameter-space able to be explored.
156 citations
Authors
Showing all 756 results
| Name | H-index | Papers | Citations |
|---|---|---|---|
| George Helou | 144 | 662 | 96338 |
| Alexander G. G. M. Tielens | 115 | 722 | 51058 |
| Gijs Nelemans | 102 | 433 | 83486 |
| Jelle Kaastra | 90 | 677 | 28093 |
| Christian Frankenberg | 79 | 286 | 19353 |
| Jeroen Homan | 72 | 354 | 15499 |
| Nanda Rea | 72 | 446 | 19881 |
| Mariano Mendez | 70 | 372 | 14475 |
| Jorick S. Vink | 70 | 311 | 18826 |
| Peter G. Jonker | 67 | 384 | 28363 |
| Michael W. Wise | 64 | 271 | 19580 |
| George Heald | 64 | 375 | 16261 |
| Pieter R. Roelfsema | 64 | 257 | 18759 |
| F. F. S. van der Tak | 63 | 314 | 16781 |
| Norbert Werner | 63 | 254 | 10741 |