CONSIDERATION OF TWO DIMENSIONAL SURFACE ROUGHNESSES IN QUANTITATIVE XPS ANALYSIS

The effect of two dimensional surface roughnesses on the intensities of XPS peaks have been investigated. The following models have been studied: square base pits with side walls perpendicular to the surface in chequered position, square base pyramid shaped pits touching each other by their edges, square base pyramids touching each other by their bottom edges, and spheres in closest packing with a planar tangent surface. On the latter model also the effect of ion etching has been studied. The application of the results are demonstrated on two quantitative surface analytical problems

Baryonic contributions to the dilepton spectrum of nucleon-nucleon collisions

We study the production of dileptons in relativistic nucleon-nucleon collisions. Additionally to the traditional dilepton production channels (vector meson decays, meson and Delta(1232) Dalitz decays) we included in our model as new dilepton sources the Dalitz decay of higher unflavored baryon resonances with spin<=5/2 and mass<=2.25 GeV/c^2. The contributions of these new channels are estimated using experimental information about the Ngamma decays of the resonances and have large uncertainties. The obtained dilepton spectra are compared to the experimental data by the DLS collaboration. Predictions for the HADES detector (SIS, GSI) are also discussed. In spite of the large uncertainties of the higher resonance Dalitz decay contributions we are able to draw the conclusion that these contributions are negligible compared to the other dilepton sources and do not influence the detectability of the phi and omega vector meson peaks.Comment: 9 pages, 4 figures, version accepted for publication in Phys. Rev.

Evidence for fresh frost layer on the bare nucleus of comet Hale--Bopp at 32 AU distance

Here we report that the activity of comet Hale--Bopp ceased between late 2007 and March, 2009, at about 28 AU distance from the Sun. At that time the comet resided at a distance from the Sun that exceeded the freeze-out distance of regular comets by an order of magnitude. A Herschel Space Observatory PACS scan was taken in mid-2010, in the already inactive state of the nucleus. The albedo has been found to be surprisingly large (8.1$\pm$0.9%{}), which exceeds the value known for any other comets. With re-reduction of archive HST images from 1995 and 1996, we confirm that the pre-perihelion albedo resembled that of an ordinary comet, and was smaller by a factor of two than the post-activity albedo. Our further observations with the Very Large Telescope (VLT) also confirmed that the albedo increased significantly by the end of the activity. We explain these observations by proposing gravitational redeposition of icy grains towards the end of the activity. This is plausible for such a massive body in a cold environment, where gas velocity is lowered to the range of the escape velocity. These observations also show that giant comets are not just the upscaled versions of the comets we know but can be affected by processes that are yet to be fully identified.Comment: 7 pages, 6 figures, accepted for publication in Ap

Photometry of SN 2002bo with template image subtraction

VRI photometry of the type Ia supernova 2002bo is presented. This SN exploded in a dusty region of the host galaxy NGC 3190, thus, subtraction of a template frame was necessary to obtain reliable photometry. We used a template frame of NGC 3190 taken during the course of our galaxy imaging project, fortunately, just a few days before SN 2002bo was discovered. The aim of this project is to collect template frames of nearby galaxies that are potential hosts of bright SNe. Subtraction of pre-SN images helped us to exclude the background light contamination of the host galaxy. The maximum occurred at JD 2452346, with maximal V brightness of 13.58. MLCS analysis led to T0(B)=JD 2452346.1 pm 0.8 (fiducial B-maximum), E(B-V)=0.24 pm 0.02, mu0=32.46 pm 0.06, Delta=-0.14 pm 0.04. E(B-V)=0.24(2) indicates a significant extinction in the host galaxy as the galactic reddening is negligible toward NGC 3190. The accepted value of Delta indicates that SN 2002bo was a slightly overluminous SN by about 0.14 relative to fiducial SN Type Ia. The distance turned out to be 31.0 pm 3 Mpc. In addition, the heavily obscured SN 2002cv was also detected on the I frame taken on JD 2452434 (June 8, 2002), and a variable star is found in the field, very close to the host galaxy.Comment: accepted by Astronomy and Astrophysic

Antitumor effect of lysine-isopeptides

Isopeptides (ε-peptides) of lysine, with a given Mw and low polydispersity (10–400 units), were synthesized to study the relationship between their chemical structure and biological effect. The designed compounds were of high purity, low polydispersity and high stereochemical purity. The effect of the compounds was tested on a human erythroleukemia cell line (K-562) and on four transplantable mouse tumors (L1210 lymphoid leukemia, P38 macrophage derived tumor, Ehrlich ascites carcinoma, Lewis lung tumor /LLT/). In case of the L1210 and P388 tumors and the Ehrlich carcinoma, survival of the animals was used as an indicator of the effect. In case of the Lewis lung tumor, the number and size of metastases in the lung and/or liver of treated and untreated mice were used as indicators. The polymers of polymerisation degree 80–120 (Mw 10.2–15.4 KD) showed the strongest antiproliferative effect both on K562 cells and the tumors growing in vivo. This effect was manifest with a significantly higher survival rate as compared to the control (L1210, P38, Ehrlich ascites), furthermore, by a decrease in the number and size of liver and lung metastases (LLT)

Pushing the limits: K2 observations of the trans-Neptunian objects 2002 GV31 and (278361) 2007 JJ43

We present the first photometric observations of trans-Neptunian objects (TNOs) taken with the Kepler space telescope, obtained in the course of the K2 ecliptic survey. Two faint objects have been monitored in specifically designed pixel masks that were centered on the stationary points of the objects, when their daily motion was the slowest. In the design of the experiment, only the apparent path of these objects were retrieved from the detectors, i.e. the costs in terms of Kepler pixels were minimized. Because of the faintness of the targets we employ specific reduction techniques and co-added images. We measure rotational periods and amplitudes in the unfiltered Kepler band as follows: for (278361) 2007 JJ43 and 2002 GV31 we get P_rot=12.097 h and P_rot=29.2 h while 0.10 and 0.35 mag for the total amplitudes, respectively. Future space missions, like TESS and PLATO are not well suited to this kind of observations. Therefore, we encourage to include the brightest TNOs around their stationary points in each observing campaign to exploit this unique capability of the K2 Mission -- and therefore to provide unbiased rotational, shape and albedo characteristics of many objects.Comment: Accepted for publication in ApJ Letters, 5.2 pages in emulateapj style, misspelled 2007 JJ43 designation correcte

HAT-P-13: a multi-site campaign to detect the transit of the second planet in the system

A possible transit of HAT-P-13c has been predicted to occur on 2010 April 28. Here we report on the results of a multi-site campaign that has been organised to detect the event. CCD photometric observations have been carried out at five observatories in five countries. We reached 30% time coverage in a 5 days interval centered on the suspected transit of HAT-P-13c. Two transits of HAT-P-13b were also observed. No transit of HAT-P-13c has been detected while the campaign was on. By a numerical experiment with 10^5 model systems we conclude that HAT-P-13c is not a transiting exoplanet with a significance level from 65% to 72%, depending on the planet parameters and the prior assumptions. We present two times of transit of HAT-P-13b ocurring at BJD 2455141.5522 +- 0.0010 and BJD 2455249.4508 +- 0.0020. The TTV of HAT-P-13b is consistent with zero within 0.001 days. The refined orbital period of HAT-P-13b is 2.916293 +- 0.000010 days.Comment: 5 pages, 4 figures, to be accepted by A&