A two-color CCD survey of the North Celestial Cap: I. The method

We describe technical aspects of an astrometric and photometric survey of the North Celestial Cap (NCC), from the Pole (δ=90°) to δ=80°, in support of the TAUVEX mission. This region, at galactic latitudes from ∼17° to ∼37°, has poor coverage in modern CCD-based surveys. The observations are performed with the Wise Observatory one-meter reflector and with a new mosaic CCD camera (LAIWO) that images in the Johnson–Cousins R and I bands a one-square-degree field with sub-arcsec pixels. The images are treated using IRAF and SExtractor to produce a final catalogue of sources. The astrometry, based on the USNO-A2.0 catalogue, is good to ∼1 arcsec and the photometry is good to ∼0.1 mag for point sources brighter than R=20.0 or I=19.1 mag. The limiting magnitudes of the survey, defined at photometric errors smaller than 0.15 mag, are 20.6 mag (R) and 19.6 (I). We separate stars from non-stellar objects based on the object shapes in the R and I bands, attempting to reproduce the SDSS star/galaxy dichotomy. The completeness test indicates that the catalogue is complete to the limiting magnitudes.     

Astrophysical supplements to the ASCC‐2.5. II. Membership probabilities in 520 Galactic open cluster sky areas

We present a catalogue (CSOCA) of stars residing in 520 Galactic open cluster sky areas which is the result of the kinematic (proper motion) and photometric member selection of stars listed in the homogeneous All‐sky Compiled Catalogue of 2.5Million Stars (ASCC‐2.5).We describe the structure and contents of the catalogue, the selection procedure applied, and the proper motion and photometric membership constraints adopted. In every cluster area the CSOCA contains the complete list of the ASCC‐2.5 stars regardless of their membership probability. For every star the CSOCA includes accurate J2000 equatorial coordinates, proper motions in the Hipparcos system, BV photometric data in the Johnson system, proper motion and photometric membership probabilities, as well as angular distances from the cluster centers for about 166 000 ASCC‐2.5 stars. If available, trigonometric parallaxes, spectral types, multiplicity and variability flags from the ASCC‐2.5, and radial velocities with their errors from the Catalogue of Radial Velocities of Galactic Stars with high precision Astrometric Data (CRVAD) are also given. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The determination of a complete sample of open clusters to compare with star clusters in other galaxies

In order to compare star cluster systems in galaxies, and consequently to obtain information on their different modalities of birth and evolution, a homogeneous and complete sample of galactic open clusters is obtained from Lynga's (1983)Catalogue of Open Clusters. This sample consists of 94 open clusters whose projected (onto the galactic plane) distance from the Sun and whose absoluteV-magnitude are smaller than 2 kpc and –4.5 mag, respectively. The completeness of the sample is based only on the usual hypothesis of a uniform projected distribution of the clusters in the solar neighbourhood. Some results concerning the distribution of relevant photometric and structural parameters are presented and discussed.     

The past photometric history of the FU Ori-type young eruptive star 2MASS J06593158-0405277 = V960 Mon

The known FU Ori-type young eruptive stars are exceedingly rare (a dozen or so confirmed objects) and 2MASS J06593158-0405277, with its 2014 outburst, is likely the latest addition to the family. All members have displayed just one such eruption in their recorded history, an event lasting for decades. To test the FU Ori nature of 2MASS J06593158-0405277, we have reconstructed its photometric history by measuring its brightness on Harvard photographic plates spanning the time interval 1899–1989. No previous large amplitude eruption similar to that initiated in 2014 has been found, as in bona fide FU Ori-type objects. The median value of the brightness in quiescence of 2MASS J06593158-0405277 is B = 15.5, with the time interval 1935–1950 characterized by a large variability ( ∼ 1 mag amplitude) that contrasts with the remarkable photometric stability displayed at later epochs. The variability during 1935–1950 can either be ascribed to some T Tau like activity of 2MASS J06593158-0405277 itself or to the also young and fainter star 2MASS J06593168-0405224 that lies 5 arcsec to the North and forms an unresolved pair at the astrometric scale of Harvard photographic plates.     

Five supernova survey galaxies in the southern hemisphere. I. Optical and near-infrared database

The determination of the supernova (SN) rate is based not only on the number of detected events, but also on the properties of the parent galaxy population. This is the first paper of a series aimed at obtaining new, refined, SN rates from a set of five SN surveys, by making use of a joint analysis of near-infrared (NIR) data. We describe the properties of the 3838 galaxies that were monitored for SNe events, including newly determined morphologies and their DENIS, and POSS-II/UKST I, 2MASS and DENIS J and K_s and 2MASS H magnitudes. We have compared 2MASS, DENIS and POSS-II/UKST IJK magnitudes in order to find possible systematic photometric shifts in the measurements. The DENIS and POSS-II/UKST I band magnitudes show large discrepancies (mean absolute difference of 0.4 mag.), mostly due to different spectral responses of the two instruments, with an important contribution (0.33 mag rms) from the large uncertainties in the photometric calibration of the POSS-II and UKST photographic plates. In the other wavebands, the limiting near infrared magnitude, morphology, and inclination of the galaxies are the most influential factors which affect the determination of photometry of the galaxies. Nevertheless, no significant systematic differences have been found between any pair of NIR magnitude measurements, except for a few percent of galaxies showing large discrepancies. This allows us to combine DENIS and 2MASS data for the J and K_s filters. Published in Astrofizika, Vol. 52, No. 1, pp. 47–62 (Februay 2009).     

Spectral and photometric behavior of SU UMa during quiescence and outburst states

We report the results of spectral and photometric observations of SU UMa. Available spectra from International Ultraviolet Explorer (IUE) and CCD photometry of five nights were used. Some profiles revealing the variations of some spectral lines at different times are presented. There is variation with time for photometric observations and the brightness of SU UMa is changed from 12.9 mag. to 15.6 mag in 5 nights with clear display of burst. The ultraviolet luminosity for emitting region is in the range of (6.9*10³⁰ erg s⁻¹). The mass accretion rate is in the range of (9.8*10⁻¹³ M_⊙yr⁻¹). The line flux modulations at different times can be explained in terms of the mass transfer instability model (Bath 1973).     

Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations

We obtained estimates of the Johnson V absolute magnitudes (H) and slope parameters (G) for 583 main-belt and near-Earth asteroids observed at Ond?ejov and Table Mountain Observatory from 1978 to 2011. Uncertainties of the absolute magnitudes in our sample are <0.21 mag, with a median value of 0.10 mag. We compared the H data with absolute magnitude values given in the MPCORB, Pisa AstDyS and JPL Horizons orbit catalogs. We found that while the catalog absolute magnitudes for large asteroids are relatively good on average, showing only little biases smaller than 0.1 mag, there is a systematic offset of the catalog values for smaller asteroids that becomes prominent in a range of H greater than ～10 and is particularly big above H ～ 12. The mean (H_catalog ? H) value is negative, i.e., the catalog H values are systematically too bright. This systematic negative offset of the catalog values reaches a maximum around H = 14 where the mean (H_catalog ? H) is ?0.4 to ?0.5. We found also smaller correlations of the offset of the catalog H values with taxonomic types and with lightcurve amplitude, up to ～0.1 mag or less. We discuss a few possible observational causes for the observed correlations, but the reason for the large bias of the catalog absolute magnitudes peaking around H = 14 is unknown; we suspect that the problem lies in the magnitude estimates reported by asteroid surveys. With our photometric H and G data, we revised the preliminary WISE albedo estimates made by Masiero et al. (Masired, J.R. et al. [2011]. Astrophys. J. 741, 68–89) and Mainzer et al. (Mainzer, A. et al. [2011b]. Astrophys. J. 743, 156–172) for asteroids in our sample. We found that the mean geometric albedo of Tholen/Bus/DeMeo C/G/B/F/P/D types with sizes of 25–300 km is p_V = 0.057 with the standard deviation (dispersion) of the sample of 0.013 and the mean albedo of S/A/L types with sizes 0.6–200 km is 0.197 with the standard deviation of the sample of 0.051. The standard errors of the mean albedos are 0.002 and 0.006, respectively; systematic observational or modeling errors can predominate over the quoted formal errors. There is apparent only a small, marginally significant difference of 0.031 ± 0.011 between the mean albedos of sub-samples of large and small (divided at diameter 25 km) S/A/L asteroids, with the smaller ones having a higher albedo. The difference will have to be confirmed and explained; we speculate that it may be either a real size dependence of surface properties of S type asteroids or a small size-dependent bias in the data (e.g., a bias towards higher albedos in the optically-selected sample of asteroids). A trend of the mean of the preliminary WISE albedo estimates increasing with asteroid size decreasing from D ～ 30 down to ～5 km (for S types) showed in Mainzer et al. (Mainzer, A. et al. [2011a]. Astrophys. J. 741, 90–114) appears to be mainly due to the systematic bias in the MPCORB absolute magnitudes that progressively increases with H in the corresponding range H = 10–14.     

Photographic photometry of the eclipsing binary ad bootes

A detailed two colour (BV) photoelectric photometry of the late-type eclipsing binary AD BOO was carried out in 1981 April–May. We found its period to be 2.0688112 d, double what was thought previously. The light curve outside the eclipses is basically flat with Irregular fluctuations of ˜0.075 mag. It is basically an Algol-type curve, with a principal minimum of 0.65 mag and a secondary minimum of 0.40 mag. The O-C diagram of the minimum epoch shows that the period has tended to increase. The photometric solution by the classical Russel-Merrill method gives k = 0.786. The principal minimum corresponds to a partial eclipse of the transit type.     

Streaming motions of galaxy clusters within 12 000 km s−1– II. New photometric data for the Fundamental Plane

We present new R -band photometric data for 447 galaxies, gathered for the 'Streaming Motions of Abell Clusters' (SMAC) project. The data comprise 629 individual measurements of the Fundamental Plane (FP) parameters effective radius ( R _e) and surface brightness (〈 μ 〉_e), derived from r ^1/4-law profile fitting. More than a third of the galaxies were observed more than once. The photometric precision is ∼0.02 mag as judged from comparisons of aperture photometry between repeat observations of galaxies. The combination     which enters into the Fundamental Plane relation, has internal uncertainties of ∼0.008, corresponding to < 2 per cent in estimated distance. Taken individually, the (correlated) internal errors in R _e and 〈 μ 〉_e are ∼8 per cent and ∼0.12 mag respectively. Comparisons with literature data constrain the external random errors to ≲5 per cent in distance (per observation), which is small in comparison to the ∼20 per cent scatter in the FP. The data will form part of a merged catalogue of FP parameters, presented in a companion paper.     

Discovery and characteristics of the Kuiper belt binary 2003QY90

We present photometric and astrometric results from four epochs of ground-based observations at the Magellan telescopes of the Kuiper belt binary 2003QY90. Resolved observations show both components to be highly variable and often of nearly equal brightness, causing difficulty in distinguishing between the primary and secondary components for observations spaced widely in time. Resolved lightcurve observations on one night show one component to have a single-peaked rotation period of 3.4±1.1 h and a peak-to-peak amplitude of 0.34±0.12 mag. The other component exhibits a less constrained lightcurve, with a single-peaked rotation period of 7.1±2.9 h and a peak-to-peak amplitude of 0.90±0.36 mag. Under the assumption of equal albedos, the diameter ratio is 1.25±0.11 in the Sloan i^′ filter. While we cannot determine an orbit from our four distinct epochs of observation (due to ambiguity in component identification), we place limits on the orbital period of the system of 300-600 days, we find a minimum semi-major axis of 13,092 km for a circular orbit and a system mass range of (2.3-18.0)×¹⁰¹⁷ kg depending on the identification of components in our observations.     

R- and J-band photometry of Comets 2P/Encke and 9P/Tempel 1

Near-simultaneous R- and J-band photometric measurements of the short-period Comets 2P/Encke and the Deep Impact mission target 9P/Tempel 1 were obtained. The resulting R-J colors are +0.82±0.08 mag and +1.46±0.13 mag for Encke and Tempel 1, respectively. Tempel 1's color is redder than the solar R-J color index of +0.76. The Tempel 1 observations directly detected the nucleus while the Encke observations likely suffered from coma contamination.     

Preliminary results for RR Lyrae stars and Classical Cepheids from the Vista Magellanic Cloud (VMC) survey

The Vista Magellanic Cloud (VMC, PI M.R. Cioni) survey is collecting K _S -band time series photometry of the system formed by the two Magellanic Clouds (MC) and the “bridge” that connects them. These data are used to build K _S -band light curves of the MC RR Lyrae stars and Classical Cepheids and determine absolute distances and the 3D geometry of the whole system using the K-band period luminosity (PLK _S ), the period–luminosity–color (PLC) and the Wesenhiet relations applicable to these types of variables. As an example of the survey potential we present results from the VMC observations of two fields centered respectively on the South Ecliptic Pole and the 30 Doradus star forming region of the Large Magellanic Cloud. The VMC K _S -band light curves of the RR Lyrae stars in these two regions have very good photometric quality with typical errors for the individual data points in the range of ∼0.02 to 0.05 mag. The Cepheids have excellent light curves (typical errors of ∼0.01 mag). The average K _S magnitudes derived for both types of variables were used to derive PLK _S relations that are in general good agreement within the errors with the literature data, and show a smaller scatter than previous studies.     

Secular light curve of 2P/Encke, a comet active at aphelion

We present the secular light curve of Comet 2P/Encke in two phase spaces, the log plot, and the time plot. The main conclusions of this work are: (a) The comet shows activity at perihelion and aphelion, caused by two different active areas: Source 1, close to the south pole, active at perihelion, and Source 2, at the north pole, centered at aphelion. (b) More than 18 physical parameters are measured from the secular light curves, many of them new, and are listed in the individual plots of the comet. Specifically we find for Source 1 the location of the turn on and turn off points of activity, RON=−1.63±0.03 AU, ROFF=+1.49±0.20 AU, TON=−87±5 d, TOFF=+94±15 d, the time lag, LAG(q)=6±1 d, the total active time, TACTIVITY=181±16 d, and the amplitude of the secular light curve, ASEC(1,1)=4.8±0.1 mag. (c) From this information the photometric age and the time-age defined in Ferrín [2005a. Icarus 178, 493-516; 2006. Icarus 185, 523-543], can be calculated, and we find P-AGE = 97 ± 8 comet years and T-AGE = 103 ± 9 comet years (cy). Thus Comet 2P/Encke is an old comet entering the methuselah stage (100 cy < age). (d) The activity at aphelion (Source 2), extends for TACTIVITY=815±30 d and the amplitude of the secular light curve is ASEC(1,Q)=3.0±0.2 mag. (e) From a new phase diagram an absolute magnitude and phase coefficient for the nucleus are determined, and we find RNUC(1,1,0)=15.05±0.14, and β=0.066±0.003. From this data we find a nucleus effective diameter DEFFE=5.12(+2.5;−1.7) km. These values are not much different from previous determinations but exhibit smaller errors. (f) The activity of Source 1 is due to H₂O sublimation because it shows curvature. The activity of Source 2 might also be due to H₂O due to the circumstantial situation that the poles point to the Sun at perihelion and aphelion. (g) We found a photometric anomaly at aphelion, with minimum brightness between +393 and +413 days after perihelion that may be an indication of topography. (h) We have re-reduced the 1858 secular light curve of Kamel [1991. Icarus 93, 226-245]. There are secular changes in 7 physical parameters, and we achieve for the first time, an absolute age calibration. We find that the comet entered the inner Solar System and began sublimating in 1645±40 AD. (i) It is concluded that the secular light curve can place constraints on the pole orientation of the nucleus of some comets, and we measure the ecliptic longitude of the south pole of 2P/Encke equal to 213.2±4.5°, in excellent agreement with other determinations of this parameter, but with smaller error. (j) Using the observed absolute magnitude of 1858 and 2003 and a suitable theoretical model, the extinction date of the comet is determined. We obtain ED=2056±3 AD, implying that the comet's lifetime is 125±12 revolutions about the Sun after entering the inner Solar System.     

Asteroid observations at low phase angles: III. Brightness behavior of dark asteroids

The results of photometric observations of eight main-belt asteroids with low surface albedo are presented. The magnitude-phase dependences including low phase angles (<1 deg) have been obtained for Asteroids 76 Freia (down to phase angle 0.1 deg, P-type), 190 Ismene (0.3 deg, P-type), 303 Josephina (0.2 deg, C-type), 309 Fraternitas (0.1 deg, C-type), 313 Chaldaea (0.1 deg, C-type), 444 Gyptis (0.8 deg, P-type), 615 Roswitha (0.1 deg, C-type), and 954 Li (0.03 deg, FCX-type). The behavior of brightness in the range of opposition effect is found to be practically linear for 190 Ismene with amplitude of opposition effect only 0.03 mag. Amplitudes of the opposition effect for other asteroids are close to a mean for this type. The obtained data allowed us also to determine the rotation periods of asteroids: 303 Josephina (12.497±0.001 h), 309 Fraternitas (11.205±0.005 h), 615 Roswitha (4.422±0.001 h) and 954 Li (7.207±0.002 h). The color indexes B-V, V-R and R-I have been determined for some asteroids.     

Is the β Pictoris member GJ 3039AB a physical binary? What the rotation periods tell us?

We have carried out a multi-band photometric monitoring of the close visual binary GJ 3039, consisting of a M4 primary and a fainter secondary component, and likely member of the young stellar association β Pictoris (24-Myr old). From our analysis we found that both components are photometric variables and, for the first time, we detected two micro-flare events. We measured from periodogram analysis of the photometric time series two rotation periods P = 3.355 d and P = 0.925 d, that we could attribute to the brighter GJ 3039A and the fainter GJ 3039B components, respectively. A comparison of these rotation periods with the period distribution of other β Pictoris members further supports that GJ 3039A is a member of this association. We find that also GJ 3039B could be a member, but the infrared magnitude differences between the two components taken from the literature and the photometric variability, which is found to be comparable in both stars, suggest that GJ 3039B could be a foreground star physically unbound to the primary A component.     

Multiwavelength study of the transient X-ray binary IGR J01583+6713

We have investigated multiband optical photometric variability and stability of the Hα line profile of the transient X-ray binary IGR J01583+6713. We set an upper limit of 0.05 mag on photometric variations in the V band over a time-scale of three months. The Hα line is found to consist of non-Gaussian profile and quite stable for a duration of two months. We have identified the spectral type of the companion star to be B2 IVe while the distance to the source is estimated to be ∼4.0 kpc. Along with the optical observations, we have also carried out analysis of X-ray data from three short observations of the source, two with the Swift –XRT and one with the RXTE –PCA. We have detected a variation in the absorption column density, from a value of  22.0 × 10²² cm⁻²  immediately after the outburst down to  2.6 × 10²² cm⁻²  four months afterwards. In the quiescent state, the X-ray absorption is consistent with the optical reddening measurement of   E ( B − V ) = 1.46  mag. From one of the Swift observations, during which the X-ray intensity was higher, we have a possible pulse detection with a period of 469.2 s. For a Be X-ray binary, this indicates an orbital period in the range of 216–561 d for this binary system.     

The CMC15, the last issue of the series “Carlsberg Meridian Catalogue,La Palma”

CMC15 is the last of the series “Carlsberg Meridian Catalogue, La Palma” and comprises all the observations made between March 1999 and March 2011 with the Carlsberg Automatic Meridian Circle in El Roque de los Muchachos Observatory on the island of La Palma (Spain). The catalogues CMC12, CMC13, and CMC14 are superseded by this one. It contains more than 122 million observations of right ascension, declination, and magnitude of stars in the magnitude range of 9^m < r′ < 17^m and declination range of –40° < δ < +50°. The catalogue internal errors in astrometry are below 30 mas in both coordinates for stars brighter than r′ = 13, reaching 60 mas for r′ = 16. The internal magnitude error is below 0.020 mag for stars brighter than r′ = 13, and about 0.090 mag for r′ = 16. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

JOINT LIGHTCURVE OBSERVATIONS OF 10 NEAR-EARTH ASTEROIDS FROM MODRA AND ONDŘEJOV

The effort in photometry of near-Earth asteroids (NEAs) at Modra Observatory has been enhanced following a recent collaboration with Ondřejov Observatory. We present a part of our collaborative work on measuring rotation lightcurve data for 10 NEAs. We derived following synodic periods P and amplitudes of their composite lightcurves: (3553), 3.1944 h, 0.08 mag; (22753), 10.24 h, 0.11 mag; (31669), 5.807 h, 0.07–0.27 mag; (40267), 4.9568 h, 1.01–1.11 mag; (66146), 2.3774 h, 0.12–0.15 mag; (88188), 2.6906 h, 0.06 mag; (103067), 9.489 h, 0.49 mag; 2001 CB₂₁, 3.302 h, 0.19 mag; 2004 LJ₁, 2.7247 h, 0.17–0.59 mag; 2004 XO₁₄, 8.417 h, 0.19–0.25 mag. While the derived periods are unique (the reliability code U=3) for most of the objects, those of (3553), (22753) and 2001 CB₂₁ are somewhat less reliable (U=2). We checked all the U=3 data for deviations from strict periodicity, but found no significant attenuation that would indicate the presence of a satellite. Absolute magnitudes in Cousins R band (H _R ) were derived for (3553), 16.05; (40267), 15.59; (88188), 16.04; 2004 XO₁₄, 15.84; errors of the first three H _R estimates are 0.20 mag, but that of 2004 XO₁₄ is <0.10 mag.     

Time-resolved CCD photometry and time-series analysis of the RR Lyrae type star RR Gem

We present the results of a time-resolved photometric and time-series analysis of an RR Lyrae type star RR Gem. The main results are as follows: we found RR Gem's pulsation period, 0.39689 d, and its V and I mean magnitudes, 11.277(V) and 11.063(I) mag respectively. We confirm its variability type as RRab/BL because it manifests the Blazhko effect, and it also exhibits asymmetric light curves(steep ascending branches), periods from 0.3 to 1.0 d and amplitudes from 0.3 to 2 mag in V. They are fundamental mode pulsators.