Search

The results of measurements in two series, each series of 4 Runs and about 50 days each Run, are presented. A multi-cathode counter with an iron cathode is used in these measurements. In both series we have observed some excess in count rates in sidereal time while no excess has been observed in terrestrial time. In the first series from 27.12.22 to 24.07.23 we have observed the excess in the period between 8 a.m. and 12 a.m. of sidereal time with a confidence level more than 6 \sigma, in the second series from 21.09.23 to 03.04.24 in the period between 6 p.m. and 10 p.m. of sidereal time with a confidence level more than 4 \sigma. The fact that in terrestrial time we do not observe a similar effect as in sidereal time suggests that probably this effect is of galactic origin and that this may be caused by dark photons. Future steps are suggested to validate these results., Comment: 8 pages, 6 figures, minor changes to the text to improve readability

The technique is described of the search for dark photons with a multicathode counter. The aim of experiment is to search for diurnal variations of the effect from conversion of dark photons at the surface of the metallic cathode. The results obtained within 160 days of the measurements are presented, Comment: 7 pages, 6 figures, minor corrections

The main points of experiment on the search of dark photons using multy-cathode counter are outlined. The evidence base to prove that the observed effect is really from dark photons is formulated. First data on diurnal variations are presented. The possible interpretation of the data is given for the case if they are expanded in future measurements., Comment: 7 pages, 3 figures, proceeding for 6th International Conference on Particle Physics and Astrophysics

NASA commissioned a research team to study Unidentified Aerial Phenomena (UAP), observations of events that cannot scientifically be identified as known natural phenomena. The Main Astronomical Observatory of NAS of Ukraine conducts an independent study of UAP also. For UAP observations, we used two meteor stations installed in Kyiv and in the Vinarivka village in the south of the Kyiv region. Two-side monitoring of the daytime sky led to the detection of two luminous objects at an altitude of 620 and 1130 km, moving at a speed of 256 and 78 km/s. Colorimetric analysis showed that the objects are dark: B - V = 1.35, V - R = 0.23. The size of objects is estimated to be more than 100 meters. The detection of these objects is an experimental fact. Estimates of their characteristics follow from observational data. The authors do not interpret these objects. Daytime sky monitoring in Kyiv with multi-color DSLR camera at a rate of 30 frames per second in August and September 2018 and in Vinarivka with a multi-color CMOS camera in October 2022 revealed several cases of dark objects (phantoms). The time of their existence is, as a rule, a fraction of a second. These are oval-shaped objects ranging in size from 20 to 100 meters with speeds from 2 to 30 km/s., Comment: 13 pages,34 figures, Kinematics and Physics of Celestial Bodies

NASA commissioned a research team to study Unidentified Aerial Phenomena (UAP), observations of events that cannot scientifically be identified as known natural phenomena. The Main Astronomical Observatory of NAS of Ukraine conducts an independent study of UAP also. For UAP observations, we used two meteor stations. Observations were performed with colour video cameras in the daytime sky. We have developed a special observation technique, for detecting and evaluating UAP characteristics. According to our data, there are two types of UAP, which we conventionally call: (1) Cosmics, and (2) Phantoms. We note that Cosmics are luminous objects, brighter than the background of the sky. Phantoms are dark objects, with contrast from several to about 50 per cent. We observe a significant number of objects whose nature is not clear. Flights of single, group and squadrons of the ships were detected, moving at speeds from 3 to 15 degrees per second. Some bright objects exhibit regular brightness variability in the range of 10 - 20 Hz. We use colourimetry methods to determine of distance to objects and evaluate their colour characteristics. Objects RGB colours of the Adobe colour system had converted to the Johnson BVR astronomical colour system using the colour corrections. Phantom shows the colour characteristics inherent in an object with zero albedos. It is a completely black body that does not emit and absorbs all the radiation falling on it. We see an object because it shields radiation due to Rayleigh scattering. An object contrast makes it possible to estimate the distance using colourimetric methods. Phantoms are observed in the troposphere at distances up to 10 - 12 km. We estimate their size from 3 to 12 meters and speeds up to 15 km/s., Comment: 8 pages, 23 figures, Odessa Astronomical Publications

We describe the experiment PHELEX (PHoton-ELectron EXperiment) on the search for dark photons of cold dark matter using a technique of multi-cathode counter developed by us for this task. We present the new data, the new upper limit for the constant of kinetic mixing and also first results of measurements of the diurnal variations in solar and stellar frames. We outline the perspectives of this method for the search of dark photons, Comment: 9 pages, 6 figures, minor corrections in text and Figure 6

In this paper we describe the apparatus used in this experiment and the procedure of data treatment. We give the latest experimental results and discuss the possibility to observe diurnal variations of the count rates due to rotation of the Earth. We outline our future plans., Comment: 9 pages, 6 figures

This article describes our approach to quantifying the characteristics of meteors such as temperature, chemical composition, and others. We are using a new approach based on colourimetry. We analyze an image of Leonid meteor-6230 obtained by Mike Hankey in 2012. Analysis of the temporal features of the meteoroid trail is performed. For determining the meteor characteristics we use the "tuning technique" in combination with a simulation model of intrusion. The progenitor of the meteor was found as an object weighing 900 kg at a speed of 36.5 km/s. The meteoroid reached a critical value of the pressure at an altitude of about 29 km in a time of about 4.6 sec with a residual mass of about 20 kg, and a residual speed of about 28 km/s. At this moment, a meteoroid exploded and destroyed. We use the meteor multicolour light curves revealed from a DSLR image in the RGB colour standard. We switch from the RGB colour system to Johnson's RVB colour system introducing colour corrections. This allows one to determine the colour characteristics of the meteor radiation. We are using a new approach based on colourimetry. Colourimetry of BGR three-beam light curves allows the identification of the brightest spectral lines. Our approach based on colourimetry allows direct measurements of temperature in the meteor trail. We find a part of the trajectory where the meteoroid radiates as an absolutely black body. The R/G and B/G light curves ratio allow one to identify the wavelengths of the emission lines using the transmission curves of the RGB filters. At the end of the trajectory, the meteoroid radiates in the lines Ca II H, K 393, 397 nm, Fe I 382, 405 nm, Mg I 517 nm, Na I 589 nm, as well as atmospheric O I 779 nm., Comment: 9 pages, 13 figures, Astronomical Schools Report

The possibility to observe the diurnal variations in the count rate of dark photons using the multicathode counters is investigated. We show that placing detectors at three different mines at different latitudes: Pyh\"asalmi in Finland, Baksan at Russia and INO in India and conducting the measurements with three different orientations of detectors one can obtain quite a complete series of data to determine the direction of the dark photon field. We present the results of the measurements fulfilled by the presently developed counters., Comment: 12 pages, 8 figures

Here we present measurements of the rates of emission of single electrons from the cathode of a proportional counter filled with a mixture of Ar + CH4 (10%) at 1 bar. We interpret the results as a possible photoelectric effect associated with hidden photons (HPs). Our results set upper limits for HPs from cold dark matter (CDM). We also discuss future options for searches for HPs from CDM using a multi-cathode counter technique., Comment: 8 pages, 7 figures, minor revisions

A search for hidden-photon (HP) dark matter using a multi-cathode counter is reported. The technique based on counting of single electrons emitted from outer cathode of the proportional counter by hidden-photons was used. The apparatus and the calibration of the counter by ultraviolet lamp are described. It is shown that this technique attains a maximum sensitivity in the energy range of Vacuum Ultraviolet. From the results of measurements we set an upper limit on the photon-HP mixing parameter \chi. A further progress of using a multi-cathode technique is discussed., Comment: 6 pages, 5 figures, presented at 4th International Conference on Particle Physics and Astrophysics (ICPPA-2018). arXiv admin note: text overlap with arXiv:1804.00870

The dark rate of single-electrons emitted from a cathode of a multi-cathode counter may be interpreted as the effect from Hidden Photons (HPs) of Cold Dark Matter (CDM). As a tentative approach the measurements have been performed at different temperatures of the counter. Preliminary results of measurements by using a counter with a copper cathode are presented. An upper limit of 4.3x10-23 for parameter ksi^2 at 2 sigma has been obtained for hypothetical conversion of hidden photon to real photon at the metallic surface with the resulting emission of single electron. The work is considered as a pure illustration of the method and the perspectives are discussed for future search of HPs by a multi-cathode counter., Comment: 6 pages, 4 figures, minor corrections

We describe a work of a multi-cathode counter of the developed design in a single electron counting mode with a cathode made of aluminum alloy. The results of the calibration of the counter are presented. The coefficient of gas amplification was found from the calibration spectra. The electric fields and operation of this detector in two configurations are described and the original idea to find the effect from electrons emitted from the surface of a cathode by difference of the rates measured in two volume configurations is expounded. Furthermore, the advantage of using a multi-cathode counter for measurement of the intensity of single electron emission from a metal is explained., Comment: 4 pages, 6 figures

The dark rate of single electrons emitted from a metal cathode of the counter depends upon a temperature. At cryogenic temperatures the dark rate measured with bi-alkaline cathodes of PMT has been found to increase by lowering the temperature of the detector. One of the possible interpretations of this effect suggests the energy trapping mechanism from the conversion of Hidden Photons of CDM at the surface of a photocathode. The measurements are planned by using a Multi-Cathode Counter (MCC) with a copper and aluminum cathodes of 0.2 m2 at temperatures from 300 K down to 220 K to spot the increase of cryogenic dark rate from Hidden Photons of CDM. The physical motivation and the description of the experiment are presented., Comment: 6 pages, 1 figure

We report on a new technique of a Multi-Cathode Counter (MCC) developed to search for hidden photon (HP) cold dark matter (CDM) with a mass from 5 to 500 eV. The method is suggested in the assumption that HP-photon mixing causes emission of single electrons from a metal cathode if the mass of hidden photon is greater than a work function of the metal. The measured effect from HP should be dependent on work function of the metal and on the structure of electronic shells of the metal used as a cathode. Potentially this can be used for a verification of the results obtained. Some preliminary results for the upper limit for mixing parameter X have been obtained for HP with a mass from 5 eV to 10 keV as a pure illustration of the potential of this technique. The efforts are continued to refine the procedure of data treatment and to improve the work of MCC. A new detector with a more developed design is under construction., Comment: 13 pages, 9 figures; v.2: minor changes/corrections made, following referee's recommendations; accepted for publication in "Advances in High Energy Physics", open special issue. arXiv admin note: text overlap with arXiv:1512.04675

A search for hidden photon cold dark matter in a mass range from 5 to 500 eV in data collected during 60 days in November and December, 2015 by a Multi-Cathode Counter (MCC) is reported. From the analyses of this data we found no evidence for the existence of HP CDM and set an upper limit on the photon-HP mixing parameter $\chi$. This is the first result obtained by direct measurements in this mass range for hidden photon CDM using a single electron event in MCC as a signature., Comment: 7 pages, 3 figures, prepared for submission to Physics Letters B

We report on a new technique of a Multi-Cathode Counter (MCC) developed to search for hidden photon (HP) cold dark matter (CDM) with a mass from 5 to 500 eV. The method suggested in the assumption that hidden photons of the mass greater than a work function of the metal, the cathode of the counter is fabricated induce emission of single electrons from a cathode. Three configurations of the same counter are used to measure the count rates R1, R2 and R3 of the single electron events during several weeks. As a measure of the effect from HP the difference R1-(R2-D3/D2xR3) has been used. Some preliminary results have been obtained on a first try to search for HP with a mass from 5 to 500 eV. The upper limit for mixing parameter X has been set on the level of 3.3x10-10 for hidden photon mass from 9 to 100 eV. In our plans is to refine the procedure of data treatment and to continue the measurements to collect more data., Comment: 10 pages, 8 figures. arXiv admin note: substantial text overlap with arXiv:1509.03033

We report on a new technique of a Multi-Cathode Counter (MCC) developed to search for hidden photon (HP) cold dark matter (CDM) with a mass from 5 to 10 eV. The method suggested in the assumption that hidden photons of the mass greater than a work function of the metal, the cathode of the counter is fabricated induce emission of single electrons from a cathode. Three configurations of the same counter are used to measure the count rates R1, R2 and R3 of the single electron events sequentially each week, where the difference R1- R2 measures the effect from HP and R3 is used as a reference sequence to monitor the counting process. At present the work is aimed to refine the procedure of data treatment and to look for long term variations which should be accounted for in the final analysis of data., Comment: 7 pages, 3 pictures