Detection of 25 new rotating radio transients at 111 MHz

Nearly all fast radio RRAT-type transients that are pulsars with rare pulses have been previously detected using decimetre wavelengths. We present here 34 transients detected at metre wavelengths in our daily monitoring at declinations -9o < decl. < +42o. 25 transients are new RRATs. We confirmed the detection of 7 RRATs based on our early observations. One of the 34 detected transients was determined to be a new pulsar J1326+3346. At the same time, out of 35 RRATs detected at the decimetre wavelengths and included in the studied area, only one was detected by us J1848+1518. The periods of 6 RRATs were found from the time of arrival of single pulses. Three quarters of all RRATs were observed more than once and the total number of RRATs in the area studied has doubled.Comment: 6 pages, 3 figures, 1 table; Astronomy and Astrophysics in pres

Optical identification of the 3C 58 pulsar wind nebula

We have performed a deep optical imaging of 3C 58 SNR with the NOT in the B and V bands to detect the optical counterpart of the associated pulsar J0295+6449 and its torus-like wind nebula visible in X-rays. We analyzed our data together with the archival data obtained with the Chandra in X-rays and with the Spitzer in the mid-IR. We detect a faint extended elliptical object with B=24.06 and V=23.11 whose peak brightness and center position are consistent at the sub-arcsecond level with the position of the pulsar. Its morphology and orientation are in excellent agreement with the torus-like pulsar nebula, seen almost edge on in X-rays although its extension is only about a half of that in X-rays. In the optical we likely see only the brightest central part of the torus with the pulsar. The object is identical to the counterpart of the torus recently detected in the mid-IR. The estimated pulsar contribution to the optical flux is less than 10%. Combinig the optical/mid-IR fluxes and X-ray power-law spectrum extracted from the spatial region constrained by the optical/IR source extent we compile a tentative multi-wavelength spectrum of the central part of the nebula. Within uncertainties of the interstellar extinction it is reminiscent of either the Crab or B0540-69 pulsar wind nebula spectra. The properties of the object strongly suggest it to be the optical counterpart of the 3C 58 pulsar + its wind nebula system, making 3C 58 the third member of such a class of the torus-like systems identified in the optical and mid-IR.Comment: 12 pages including 7 figures, submitted for publication in A&A. For high resolution images, see http://www.ioffe.ru/astro/NSG/obs/3C58

Formation of "Lightnings" in a Neutron Star Magnetosphere and the Nature of RRATs

The connection between the radio emission from "lightnings" produced by the absorption of high-energy photons from the cosmic gamma-ray background in a neutron star magnetosphere and radio bursts from rotating radio transients (RRATs) is investigated. The lightning length reaches 1000 km; the lightning radius is 100 m and is comparable to the polar cap radius. If a closed magnetosphere is filled with a dense plasma, then lightnings are efficiently formed only in the region of open magnetic field lines. For the radio emission from a separate lightning to be observed, the polar cap of the neutron star must be directed toward the observer and, at the same time, the lightning must be formed. The maximum burst rate is related to the time of the plasma outflow from the polar cap region. The typical interval between two consecutive bursts is ~100 s. The width of a single radio burst can be determined both by the width of the emission cone formed by the lightning emitting regions at some height above the neutron star surface and by a finite lightning lifetime. The width of the phase distribution for radio bursts from RRATs, along with the integrated pulse width, is determined by the width of the bundle of open magnetic field lines at the formation height of the radio emission. The results obtained are consistent with the currently available data and are indicative of a close connection between RRATs, intermittent pulsars, and extreme nullers.Comment: 24 pages, no figures, references update

Detection of Giant Pulses in pulsar PSR J1752+2359

We report the detection of Giant Pulses (GPs) in the pulsar PSR J1752+2359. About one pulse in 270 has a peak flux density more than 40 times the peak flux density of an average pulse (AP), and the strongest GP is as large as 260. The energy of the strongest GP exceeds the energy of the average pulse by a factor of 200 which is greater than in other known pulsars with GPs. PSR J1752+2359 as well as the previously detected pulsars PSR B0031-07 and PSR B1112+50, belong to the first group of pulsars found to have GPs without a strong magnetic field at the light cylinder.Comment: 5 pages, 4 figures, 1 table. Accepted for publication in A&

Phase and Intensity Distributions of Individual Pulses of PSR B0950+08

The distribution of the intensities of individual pulses of PSR B0950+08 as a function of the longitudes at which they appear is analyzed. The flux density of the pulsar at 111 MHz varies strongly from day to day (by up to a factor of 13) due to the passage of the radiation through the interstellar plasma (interstellar scintillation). The intensities of individual pulses can exceed the amplitude of the mean pulse profile, obtained by accumulating 770 pulses, by more than an order of magnitude. The intensity distribution along the mean profile is very different for weak and strong pulses. The differential distribution function for the intensities is a power law with index n = -1.1 +- 0.06 up to peak flux densities for individual pulses of the order of 160 Jy

Review of scientific topics for Millimetron space observatory

This paper describes outstanding issues in astrophysics and cosmology that can be solved by astronomical observations in a broad spectral range from far infrared to millimeter wavelengths. The discussed problems related to the formation of stars and planets, galaxies and the interstellar medium, studies of black holes and the development of the cosmological model can be addressed by the planned space observatory Millimetron (the "Spectr-M" project) equipped with a cooled 10-m mirror. Millimetron can operate both as a single-dish telescope and as a part of a space-ground interferometer with very long baseline.Comment: The translation of the original article in Physics Uspekhi http://ufn.ru/ru/articles/2014/12/c

Toward An Empirical Theory of Pulsar Emission. VII. On the Spectral Behavior of Conal Beam Radii and Emission Heights

In this paper we return to the old problem of conal component-pair widths and profile dimensions. Observationally, we consider a set of 10 pulsars with prominent conal component pairs, for which well measured profiles exist over the largest frequency range now possible. Apart from some tendency to narrow at high frequency, the conal components exhibit almost constant widths. We use all three profile measures, the component separation as well as the outside half-power and 10% widths, to determine conal beam radii, which are the focus of our subsequent analysis. These radii at different frequencies are well fitted by a relationship introduced by Thorsett (1991), but the resulting parameters are highly correlated. Three different types of behavior are found: one group of stars exhibits a continuous variation of beam radius which can be extrapolated down to the stellar surface along the ``last open field lines''; a second group exhibits beam radii which asymptotically approach a minimum high frequency value that is 3--5 times larger; and a third set shows almost no spectral change in beam radius at all. The first two behaviors are associated with outer-cone component pairs; whereas the constant separation appears to reflect inner-cone emission.Comment: 21 pages, 11 figures, accepted for publication in Astrophysical Journal, uses aaste

GEMINGA: NEW OBSERVATIONS AT LOW RADIO FREQUENCIES

ABSTRACT. After nearly 10 years, we have succeeded to detect radio emission from Geminga more again. In this report we present new evidence for presence of radio emission from Geminga in the range 42-112 MHz. The observations were carried out on two sensitive transit radio telescopes We used three new digital receivers to detect the pulses and to obtain dynamic spectra.The examples of mean pulse profiles are presented. Exact value of the dispersion measure have been calculated using the simultaneous observations at three frequencies