Nature of cyclical changes in the timing residuals from the pulsar B1642-03

We report an analysis of timing data for the pulsar B1642-03 (J1645-0317) gathered over the 40-year time span between 1969 and 2008. During this interval, the pulsar experienced eight glitch-like events with a fractional increase in the rotation frequency Deltanu/nu=(0.9-2.6)x10^{-9}. We have revealed two important relations in the properties of these peculiar glitches. The first result shows that there is a strong linear correlation between the amplitude of the glitch and the time interval to the next glitch. The second result shows that the amplitude of the glitches is modulated by a periodic large-scale sawtooth-like function. As a result of this modulation, the glitch amplitude varies discretely from glitch to glitch with a step of 1.5x10^{-9} Hz in the range (2.4-6.9)x10^{-9} Hz. The post-glitch time interval also varies discretely with a step of about 600 days in the range 900-2700 days. An analysis of the data showed that three modulation schemes with modulation periods of 43 years, 53 years and 60 years are possible. The best model is the 60-year modulation scheme including 12 glitches. We make a conclusion that the nature of the observed cyclical changes in the timing residuals from PSR B1642-03 is a continuous generation of peculiar glitches whose amplitudes are modulated by a periodic large-scale sawtooth-like function. As the modulation function is periodical, the picture of cyclical timing residuals will be exactly repeated in each modulation period or every 60 years.Comment: 26 pages, 9 figures. Accepted for publication in the Astrophysical Journa

Proposal title - Search for C15 to C30 alkanes in lunar soils Final report

Lack of heavy alkanes in Apollo 11 and 12 lunar soil sample

Detection of Bursts from FRB 121102 with the Effelsberg 100-m Radio Telescope at 5 GHz and the Role of Scintillation

FRB 121102, the only repeating fast radio burst (FRB) known to date, was discovered at 1.4 GHz and shortly after the discovery of its repeating nature, detected up to 2.4 GHz. Here we present three bursts detected with the 100-m Effelsberg radio telescope at 4.85 GHz. All three bursts exhibited frequency structure on broad and narrow frequency scales. Using an autocorrelation function analysis, we measured a characteristic bandwidth of the small-scale structure of 6.4$\pm$1.6 MHz, which is consistent with the diffractive scintillation bandwidth for this line of sight through the Galactic interstellar medium (ISM) predicted by the NE2001 model. These were the only detections in a campaign totaling 22 hours in 10 observing epochs spanning five months. The observed burst detection rate within this observation was inconsistent with a Poisson process with a constant average occurrence rate; three bursts arrived in the final 0.3 hr of a 2 hr observation on 2016 August 20. We therefore observed a change in the rate of detectable bursts during this observation, and we argue that boosting by diffractive interstellar scintillations may have played a role in the detectability. Understanding whether changes in the detection rate of bursts from FRB 121102 observed at other radio frequencies and epochs are also a product of propagation effects, such as scintillation boosting by the Galactic ISM or plasma lensing in the host galaxy, or an intrinsic property of the burst emission will require further observations.Comment: Accepted to ApJ. Minor typos correcte

Cyclical Changes in the Timing Residuals from the Pulsar B0919+06

We report the detection of a large glitch in the pulsar B0919+06 (J0922+0638). The glitch occurred in 2009 November 5 (MJD 55140) and was characterized by a fractional increase in the rotation frequency of Deltanu/nu=1.3x10^{-6}. A large glitch happens in the pulsar whose rotation has unstable character. We present the results of the analysis of the rotation behavior of this pulsar over the 30-year time span from 1979 to 2009. These results show that the pulsar's rotation frequency underwent continuous, slow oscillations which look like glitch-like events. During the 1991-2009 interval, the pulsar experienced a continuous sequence of 12 slow glitches with a fractional increase in the rotation frequency Deltanu/nu=1.5x10^{-9}. All the slow glitches observed have a similar signature related to a slow increase in the rotation frequency during 200 days and the subsequent relaxation back to the pre-glitch value during 400 days. We show that a continuous sequence of such slow glitches is characterized by practically identical amplitudes equal to Deltanu=3.5x10^{-9} Hz and identical time intervals between glitches of about 600 days and is well described by a periodic sawtooth-like function. The detection of two different phenomena, such as a large glitch and a sequence of slow glitches, indicates the presence of two types of discontinuities in the rotation frequency of the pulsar B0919+06. These discontinuities can be classified as normal and slow glitches.Comment: 24 pages, 5 figures. Submitted to Ap

The MUCHFUSS photometric campaign

Hot subdwarfs (sdO/Bs) are the helium-burning cores of red giants, which lost almost all of their hydrogen envelopes. This mass loss is often triggered by common envelope interactions with close stellar or even substellar companions. Cool companions like late-type stars or brown dwarfs are detectable via characteristic light curve variations like reflection effects and often also eclipses. To search for such objects we obtained multi-band light curves of 26 close sdO/B binary candidates from the MUCHFUSS project with the BUSCA instrument. We discovered a new eclipsing reflection effect system ($P=0.168938$~d) with a low-mass M dwarf companion ($0.116 M_{\rm \odot}$). Three more reflection effect binaries found in the course of the campaign were already published, two of them are eclipsing systems, in one system only showing the reflection effect but no eclipses the sdB primary is found to be pulsating. Amongst the targets without reflection effect a new long-period sdB pulsator was discovered and irregular light variations were found in two sdO stars. The found light variations allowed us to constrain the fraction of reflection effect binaries and the substellar companion fraction around sdB stars. The minimum fraction of reflection effect systems amongst the close sdB binaries might be greater than 15\% and the fraction of close substellar companions in sdB binaries might be as high as $8.0\%$. This would result in a close substellar companion fraction to sdB stars of about 3\%. This fraction is much higher than the fraction of brown dwarfs around possible progenitor systems, which are solar-type stars with substellar companions around 1 AU, as well as close binary white dwarfs with brown dwarf companions. This might be a hint that common envelope interactions with substellar objects are preferentially followed by a hot subdwarf phase.Comment: accepted for A&

Observations of three slow glitches in the spin rate of the pulsar B1822-09

Three slow glitches in the rotation rate of the pulsar B1822-09 were revealed over the 1995-2004 interval. The slow glitches observed are characterized by a gradual increase in the rotation frequency with a long timescale of several months, accompanied by a rapid decrease in the magnitude of the frequency first derivative by 1-2 per cent of the initial value and subsequent exponential increase back to its initial value on the same timescale. The cumulative fractional increase in the pulsar rotation rate for the three glitches amounts to Delta_nu/nu ~ 7 10^{-8}.Comment: 11 pages, 3 figures. Accepted for publication in MNRA

Hitchhiking transport in quasi-one-dimensional systems

In the conventional theory of hopping transport the positions of localized electronic states are assumed to be fixed, and thermal fluctuations of atoms enter the theory only through the notion of phonons. On the other hand, in 1D and 2D lattices, where fluctuations prevent formation of long-range order, the motion of atoms has the character of the large scale diffusion. In this case the picture of static localized sites may be inadequate. We argue that for a certain range of parameters, hopping of charge carriers among localization sites in a network of 1D chains is a much slower process than diffusion of the sites themselves. Then the carriers move through the network transported along the chains by mobile localization sites jumping occasionally between the chains. This mechanism may result in temperature independent mobility and frequency dependence similar to that for conventional hopping.Comment: a few typos correcte

Nuclear basket protein ZC3HC1 and its yeast homolog Pml39p feature an evolutionary conserved bimodular construction essential for initial binding to NPC-anchored homologs of scaffold protein TPR

Proteins ZC3HC1 and TPR are construction elements of the nuclear pore complex (NPC)-attached nuclear basket (NB). NB-location of ZC3HC1 depends on TPR already occurring NPC-anchored, whereas additional TPR polypeptides are appended to the NB by ZC3HC1. The current study examined the molecular properties of ZC3HC1 that enable it to bind to the NB and TPR. We report the identification and definition of a nuclear basket-interaction domain (NuBaID) of HsZC3HC1 comprising two similarly built modules, both essential for the binding to the NB’s NPC-anchored HsTPR. Furthermore, we describe such a bimodular construction as evolutionarily conserved and exemplify the kinship of HsZC3HC1 by the NB- and DdTPR-interacting homolog of Dictyostelium discoideum and by characterizing protein Pml39 as the ZC3HC1 homolog in Saccharomyces cerevisiae. Among several properties shared by the different species’ homologs, we unveil the integrity of the bimodular NuBaID of ScPml39p as being essential for binding to the yeast’s NBs and its TPR homologs ScMlp1p and ScMlp2p, and we further present Pml39p as enabling interlinkage of Mlp1p subpopulations. In addition to phyla-specific features, we delineate the three species’ common NuBaID as the characterizing structural entity of a one-of-a-kind protein found not in all but likely most taxa of the eukaryotic realm