High Speed Phase-Resolved 2-d UBV Photometry of the Crab pulsar

We report a phase-resolved photometric and morphological analysis of UBV data of the Crab pulsar obtained with the 2-d TRIFFID high speed optical photometer mounted on the Russian 6m telescope. By being able to accurately isolate the pulsar from the nebular background at an unprecedented temporal resolution (1 \mu s), the various light curve components were accurately fluxed via phase-resolved photometry. Within the $UBV$ range, our datasets are consistent with the existing trends reported elsewhere in the literature. In terms of flux and phase duration, both the peak Full Width Half Maxima and Half Width Half Maxima decrease as a function of photon energy. This is similarly the case for the flux associated with the bridge of emission. Power-law fits to the various light curve components are as follows; \alpha = 0.07 \pm 0.19 (peak 1), \alpha = -0.06 \pm 0.19 (peak 2) and \alpha = -0.44 \pm 0.19 (bridge) - the uncertainty here being dominated by the integrated CCD photometry used to independently reference the TRIFFID data. Temporally, the main peaks are coincident to \le 10 \mu s although an accurate phase lag with respect to the radio main peak is compromised by radio timing uncertainties. The plateau on the Crab's main peak was definitively determined to be \leq 55 \mu s in extent and may decrease as a function of photon energy. There is no evidence for non-stochastic activity over the light curves or within various phase regions, nor is there evidence of anything akin to the giant pulses noted in the radio. Finally, there is no evidence to support the existence of a reported 60 second modulation suggested to be as a consequence of free precession.Comment: 13 pages, 12 figures, accepted for publication in Astronomy & Astrophysic

The census of cataclysmic variables in the ROSAT Bright Survey

We give an identification summary and results of polarimetric, photometric and spectroscopic follow-up observations of new, X-ray bright cataclysmic variables. These were identified as optical counterparts of high galactic latitude sources in the ROSAT All-Sky Survey. This optical identification programme is termed the ROSAT Bright Survey (RBS) and represents the first complete soft X-ray selected, flux-limited sample of CVs at high galactic latitude (survey area ~20400 sq.deg.). The systems described here escaped previous identification programmes since these surveys were designed to identify even brighter than ours or particularly soft X-ray sources. Among the 11 new RBS-CVs we find 6 magnetic systems of AM Herculis type, 4 dwarf novae (among them one candidate), and one particularly bright system of uncertain nature, tentatively identified as dwarf nova or symbiotic binary. Orbital periods could be determined for all magnetic systems which range from 87.1 min to 187.7 min. Three of the new dwarf novae have moderate to high inclination and two of them might be eclipsing. Using non-magnetic systems only we derive a space density of CVs of ~3 10^{-5} pc^{-3}. This limit rests on the two new nearby, low-luminosity systems RBS0490 and RBS1955, with estimated distances of 30pc only and luminosities below 10^{30} erg s^{-1}.Comment: Astronomy and Astrophys., in press, 17 pages, 19 figures, full paper with finding charts at http://www.aip.de/People/ASchwope/axels_papers.htm

ТАКСОНОМИЯ КАК ИНСТРУМЕНТ СТРАТЕГИИ

The article underlines the importance of employment of taxonomy for project and program management. The actuality of reviewed problems refers to the lack of investments when a business is under crisis conditions and the limited resources in project portfolio are redistributed and sequestered.Статья характеризует значимость  применения таксономии  в управлении проектами  и программами. Актуальность  поднимаемых в ней проблем связана  с нехваткой инвестиций в кризисных  для бизнеса условиях, когда  в портфеле проектов предприятия  постоянно идет перераспределение  и секвестирование жестко  ограниченных ресурсов

A Search for the Optical Counterpart of PSR B1951+32 in the Supernova Remnant CTB 80

Using time-resolved two-dimensional aperture photometry we have put upper limits on the pulsed emission from two proposed optical counterparts for PSR B1951+32. Our pulsed upper limits of m_{vpulsed}>23.3, m_{bpulsed}>24.4$, for the first candidate and m_{vpulsed}>23.6$, m_{bpulsed}>24.3 for the second, make it unlikely that either of these is, in fact, the pulsar. We discuss three further candidates, but also reject these on the basis of timing results. A search of a 5.5arcs x 5.5arcs area centred close to these stars failed to find any significant pulsations at the reported pulsar period.Comment: 5 pages, 4 figures, typos correcte

BLR kinematics and Black Hole Mass in Markarian 6

We present results of the optical spectral and photometric observations of the nucleus of Markarian 6 made with the 2.6-m Shajn telescope at the Crimean Astrophysical Observatory. The continuum and emission Balmer line intensities varied more than by a factor of two during 1992-2008. The lag between the continuum and Hbeta emission line flux variations is 21.1+-1.9 days. For the Halpha line the lag is about 27 days but its uncertainty is much larger. We use Monte-Carlo simulation of the random time series to check the effect of our data sampling on the lag uncertainties and we compare our simulation results with those obtained by random subset selection (RSS) method of Peterson et al. (1998). The lag in the high-velocity wings are shorter than in the line core in accordance with the virial motions. However, the lag is slightly larger in the blue wing than in the red wing. This is a signature of the infall gas motion. Probably the BLR kinematic in the Mrk 6 nucleus is a combination of the Keplerian and infall motions. The velocity-delay dependence is similar for individual observational seasons. The measurements of the Hbeta line width in combination with the reverberation lag permits us to determine the black hole mass, M_BH=(1.8+-0.2)x10^8 M_sun. This result is consistent with the AGN scaling relationships between the BLR radius and the optical continuum luminosity (R_BLR is proportional to L^0.5) as well as with the black-hole mass-luminosity relationship (M_BH-L) under the Eddington luminosity ratio for Mrk 6 to be L_bol/L_Edd ~ 0.01.Comment: 17 pages, 10 figures, accepted for publication in MNRA

Estudio óptico de LMXBS con alta resolución temporal evidencia de flares no térmicos en MXB 1735-44

We present a search for ultrafast optical variability among some low-mass X-ray binaries (LMXBS) using MANIA complex (Multichannel Analisys of Nanosecond Intensity Alterations) attached to the 2.15 m telescope of CASLEO. Two flares of ∼ 0.25 sec in duration were recorded from the MXB 1735-44 X-ray burster. Brightness of the object increased 15-30 times during these flares, with very steep forward fronts (characteristic rising time being ∼ 0.05-0.06 sec), and displaying a fine structure in time-scale of 0.005-0.006 sec (confidence level > 95%). Brightness temperatures of these phases within the flares were more than 5x10⁷,10⁸ K, respectively, which can only be explained by non-thermal processes. These results are an evidence that in MXB 1735-44 there exist some departures from standard model of accretion onto compact objects.Asociación Argentina de Astronomí

Intermediate resolution H-beta spectroscopy and photometric monitoring of 3C 390.3 I. Further evidence of a nuclear accretion disk

We have monitored the AGN 3C390.3 between 1995 and 2000.Two large amplitude outbursts, of different duration, in continuum and H beta light were observed ie.: in October 1994 a brighter flare that lasted about 1000 days and in July 1997 another one that lasted about 700 days were detected. The flux in the H beta wings and line core vary simultaneously, a behavior indicative of predominantly circular motions in the BLR.Important changes of the Hbeta emission profiles were detected: at times, we found profiles with prominent asymmetric wings, as those normaly seen in Sy1s, while at other times, we observe profiles with weak almost symmetrical wings, similar to those seen in Sy1.8s. We found that the radial velocity difference between the red and blue bumps is anticorrelated with the light curves of H beta and continuum radiation.e found that the radial velocity difference between the red and blue bumps is anticorrelated with the light curves of H-beta and continuum radiation. Theoretical H-beta profiles were computed for an accretion disk, the observed profiles are best reproduced by an inclined disk (25 deg) whose region of maximum emission is located roughly at 200 Rg. The mass of the black hole in 3C 390.3, estimated from the reverberation analysis is Mrev = 2.1 x 10^9 Msun, ie. 5 times larger than previous estimatesComment: 18 pages, 13 figures, 4 tables. to appear in Astronomy and Astrophysic

Optical photometry of the PSR B0656+14 and its neighborhood

We present the results of the broad-band photometry of the nearby middle-aged radio pulsar PSR B0656+14 and its neighborhood obtained with the 6-meter telescope of the SAO RAS and with the Hubble Space Telescope. The broad-band spectral flux $F_\nu$ of the pulsar decreases with increasing frequency in the near-IR range and increases with frequency in the near-UV range. The increase towards UV can be naturally interpreted as the Rayleigh-Jeans tail of the soft thermal component of the X-ray spectrum emitted from the surface of the cooling neutron star. Continuation of the power-law component, which dominates in the high-energy tail of the X-ray spectrum, to the IR-optical-UV frequencies is consistent with the observed fluxes. This suggests that the non-thermal pulsar radiation may be of the same origin in a broad frequency range from IR to hard X-rays. We also studied 4 objects detected in the pulsar's 5" neighborhood.Comment: 12 pages, 20 figures, submitted to A&A. Images are available in FITS format at http://www.ioffe.rssi.ru/astro/NSG/obs/0656-phot.htm