view Abstract Citations (193) References (45) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Giant Pulses from the Crab Pulsar: A Joint Radio and Gamma-Ray Study Lundgren, S. C. ; Cordes, J. M. Ulmer, Matz, Lomatch, Foster, R. Hankins, T. The Nebula pulsar emits bursts of radio emission as strong 2000 times average pulse amplitude. Using joint gamma-ray observations these giant pulses, we characterized intensity variations, measured absolute timing with 70...

Our high time resolution observations of individual pulses from the Crab pulsar show that both and frequency signatures interpulse are distinctly different those main pulse. Main can occasionally be resolved into short-lived, relatively narrowband nanoshots. We believe these nanoshots produced by soliton collapse in strong plasma turbulence. Interpulses at centimeter wavelengths very different. Their dynamic spectrum contains regular, microsecond-long emission bands. have detected bands,...

view Abstract Citations (146) References (10) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Microsecond Intensity Variations in the Radio Emissions from CP 0950 Hankins, T. H. A technique for removal of effect dispersion by interstellar medium radio emission pulsars has been developed. Observations pulsar over a bandwidth 125 kHz at 111.5 MHz have revealed time structure as short reciprocal limit 8 microseconds. Occasional isolated subpulses 40000 flux...

We have carried out new, high-frequency, high-time-resolution observations of the Crab pulsar. Combining these with our previous data, we characterize bright single pulses associated Main Pulse, both Low-Frequency and High-Frequency Interpulses, two Components. Our data include at frequencies ranging from 1 to 43 GHz time resolution down a fraction nanosecond. find least types emission physics are operating in this Both Pulses up about 10 GHz, characterized by nanoshot - overlapping clumps...

We have observed the pulsar in Crab Nebula at high radio frequencies and time resolution. present continuously sampled data 640 ns resolution individual bright pulses recorded down to 0.25 Combining our new with previous from group literature shows dramatic changes pulsar's emission between low frequencies. Below about 5 GHz mean profile is dominated by Main Pulse Low-Frequency Interpulse. Everything changes, however, above GHz; disappears of High-Frequency Interpulse (which quite different...

We analyze the Crab pulsar at 10 frequencies from 0.43 to 8.8 GHz using data obtained Arecibo Observatory and report spectral dependence of all pulse components rate occurrence large-amplitude "giant" pulses. Giant pulses occur only in main interpulse that are manifest radio gamma-ray energies (known as "P1" "P2" high-energy literature). Individual giant reach brightness temperatures least 1032 K our data, which do not resolve narrowest pulses, known 1037 nanosecond-resolution observations...

view Abstract Citations (124) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Multifrequency Radio Observations of the Crab Pulsar Moffett, David A. ; Hankins, Timothy H. Previously unseen profile components pulsar have been discovered in a study frequency-dependent behavior its average pulse between 0.33 and 8.4 GHz. One new component, 36° ahead main at 1.4 GHz, is not coincident with position precursor lower frequencies. Two additional,...

A search for erenkov emission in the radio-frequency range resulting from particle cascade of an ultrahigh-energy neutrino on near surface Moon is described. The expected pulse 1-ns duration, dispersed by propagation through Earth's ionosphere, with amplitude approximately 400 Jy was not detected 10 h observations.

view Abstract Citations (112) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The mode-switching phenomenon in pulsars. Bartel, N. ; Morris, D. Sieber, W. Hankins, T. H. Observations of the mode switching pulsars PSR 0329+54 and 1237+25 during years 1975-1979 1972-1977 with 100 m, 25 305 m radio telescopes are reported. were sampled at intervals 0.0003 periods, least as long interstellar dispersion sweep time signal across filter bandwidth....

view Abstract Citations (141) References (21) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Eclipsing Millisecond Pulsar PSR 1957+20 Fruchter, A. S. ; Berman, G. Bower, Convery, M. Goss, W. Hankins, T. H. Klein, J. R. Nice, D. Ryba, F. Stinebring, Taylor, Thorsett, E. Weisberg, Information obtained over the past year on eclipsing millisecond pulsar 1957 + 20 and its orbiting companion is discussed. found to be similar in many ways other pulsars: spin...

We have monitored the radio flux density of 21 pulsars on a daily basis for five years. The 610 MHz time series these range from nearly constant most distant and heavily scattered to rapidly varying, saturated more nearby pulsars. measured stability (variations less than 5%) implies that average emission pulsars, before it has been affected by propagation through interstellar medium, is in strength timescales few hours several modulation index variations never exceeds 0.5, ruling out...

We review our high-time-resolution radio observations of the Crab pulsar and compare data to a variety models for emission physics. The Main Pulse Low Frequency Interpulse come from regions somewhere in high-altitude zones (caustics) that also produce pulsed X-ray ${\it\gamma}$ -ray emission. Although no model can fully explain these two components, most likely suggest they arise combination beam-driven instabilities, coherent charge bunching strong electromagnetic turbulence. Because power...

Simultaneous measurements of giant pulses from the Crab pulsar were taken at two widely spaced frequencies, using real-time detection a pulse 1.4 GHz Very Large Array to trigger observation that same 0.6 25 m telescope in Green Bank, WV. Interstellar dispersion signals provided necessary time communicate across country via Internet. About 70% are seen both and GHz, implying an emission mechanism bandwidth least 0.8 1 for structure on timescales 10 μs. The spectral indices fall between -2.2...

view Abstract Citations (60) References (21) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Null Transition Times, Quantized Drift Modes, and No Memory across Nulls for PSR 1944+17 Deich, W. T. S. ; Cordes, J. M. Hankins, H. Rankin, The authors have studied the behavior of drifting subpulses nulling in (P = 0.441 s), an object which allows a large number null transitions to be examined, since 60% pulses are pulses. evidence phase memory is found, but there...

We present Arecibo time-aligned, total intensity profiles for 46 pulsars over an unusually wide range of radio frequencies and multi-frequency, polarization-angle density diagrams, and/or polarization 57 at some or all the 50, 111/130, 430, 1400 MHz. The frequency-dependent dispersion delay has been removed in order to align study their spectral evolution, wherever possible each pulsar are displayed on same longitude scale. Most within Arecibo's declination that sufficiently bright such...

view Abstract Citations (58) References (5) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Short-Timescale Structure in Two Pulsars Hankins, T. H. Frequency-independent characteristic timescales of 175 and 575 s have been found, using a new predetection dispersion-removal technique, the intensity structure meter-wavelength radio signals from pulsars CP 0950 1133. Publication: The Astrophysical Journal Pub Date: October 1972 DOI: 10.1086/181043 Bibcode:...

view Abstract Citations (70) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Interpulse emission from pulsar 0950+08 : how many poles ? Hankins, T. H. ; Cordes, J. M. Consideration of the frequency dependence over entire pulse period shows that: (1) interpulse is accompanied by low level at least 83% rotation period; (2) individual interpulses may be as strong 60% average main pulse, comparison to an interpulse-main ratio 2%; (3) are...

view Abstract Citations (50) References (12) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The radio spectrum of micropulses from pulsar PSR 0950+08. Rickett, B. J. ; Hankins, T. H. Cordes, M. microstructure in the pulses 0950+08 has been studied over both wide and narrow frequency ranges. characterized by 0.17 ms duration are broad-band, exhibiting 50 percent correlation between 111 318 MHz. Over 125 kllz centered on MHz dynamic spectra individual show...

New polarimetric observations of the Crab pulsar at frequencies between 1.4 and 8.4 GHz are presented. Additional pulse components discovered in earlier found to have high levels linear polarization, even GHz. No abrupt sweeps position angle within components; however, rotational phase interpulse do change dramatically 4.9 The multifrequency profile morphology polarization properties indicate a nonstandard origin emission. Several emission geometries discussed, but one favored locates sites...

A detailed analysis of microstructure in the radio emissions from five pulsars is presented, with particular emphasis on quasi-periodicities microstructure. Two objects (PSRs 0950 + 08 and 1133 16) show only about 5-10 percent pulse periods whereas three that display drifting subpulses 0809 74, 1944 17, 2016 28) almost always The for two (1944 17 strongest at meter wavelengths its contribution to intensity decreases roughly as nu -3. quasi-periods periodic vary over a 10:1 range an average...

view Abstract Citations (60) References (32) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Frequency Dependence of the Main Pulse to Interpulse Separation for Seven Pulsars Hankins, T. H. ; Fowler, L. A. In course a study pulsar interpulses 43 bright pulsars were searched interpulse emission. A previously undetected in PSR 1944 + 17 was found and improved upper limits set on others. The separation Delta-phi (MP-IP) between main pulse (MP) (IP) IP MP...

view Abstract Citations (40) References (20) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Drifting Subpulse Phenomenon Observed in Three Pulsars with Triple Profiles Hankins, T. H. ; Wolszczan, A. pulsars (PSRs 1632+24, 1845-01, and 1918+19) triple average profile shapes have been found which subpulses that drift across the full window. These are first known triple-profile objects to show clear drifting. emission details can be understood context of...