- ID:
- ivo://CDS.VizieR/J/MNRAS/387/344
- Title:
- BVRcIC photometry of V2615 Oph
- Short Name:
- J/MNRAS/387/344
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The moderately fast Nova Oph 2007 reached maximum brightness on 2007 March 28 at V=8.52, B-V=+1.12, V-Rc=+0.76, V-Ic=+1.59 and Rc-Ic=+0.83 , after fast initial rise and a pre-maximum halt lasting a week. Decline times were t^V^_2_=26.5, t^B^_2_=30, t^V^_3_=48.5 and t^B^_3_=56.5d. The distance to the nova is d=3.7+/-0.2kpc , the height above the Galactic plane is z=215pc, the reddening is E(B-V)=0.90 and the absolute magnitude at maximum is M^max^_V_=-7.2 and M^max^_B_=-7.0. The spectrum four days before maximum resembled a F6 supergiant, in an agreement with broad-band colours. It later developed into that of a standard 'FeII'-class nova. Nine days past maximum, the expansion velocity estiIIted from the width of H{alpha} emission component was ~730km/s, and the displacement from it of the principal and diffuse-enhanced absorption systems was ~650 and 1380km/s, respectively. Dust probably formed and disappeared during the period from 82 to 100d past maximum, causing (at peak dust concentration) an extinction of {Delta}B=1.8mag and an extra {Delta}E(B-V)=0.44 reddening.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/888/30
- Title:
- BVRI and spectroscopic light curves of S5 0716+714
- Short Name:
- J/ApJ/888/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to study short timescale optical variability of {gamma}-ray blazar S5 0716+714, quasi-simultaneous spectroscopic and multiband photometric observations were performed from 2018 November to 2019 March with the 2.4m optical telescope located at Lijiang Observatory of Yunnan Observatories. The observed spectra are well fitted with a power law F_{lambda}_=A{lambda}^-{alpha}^ (spectral index {alpha}>0). Correlations found between {dot}{alpha}, {dot}A, {dot}A/A, {dot}F_{lambda}_, and {dot}F_{lambda}_/F_{lambda}_ are consistent with the trend of bluer-when-brighter (BWB). It is the same case for colors, magnitudes, color variation rates, and magnitude variation rates of photometric observations. The variations of {alpha} lead those of F_{lambda}_. Also, the color variations lead magnitude variations. The observational data are mostly distributed in the I(+,+) and III(-,-) quadrants of the coordinate system. Both spectroscopic and photometric observations show BWB behaviors in S5 0716+714. The observed BWB may be explained by the shock-jet model, and its appearance may depend on the relative position of the observational frequency ranges with respect to the synchrotron peak frequencies, e.g., at the left of the peak frequencies. Fractional variability amplitudes are F_var_~40% for both spectroscopic and photometric observations. Variations of {alpha} indicate variations of relativistic electron distribution producing the optical spectra.
- ID:
- ivo://CDS.VizieR/J/A+A/445/901
- Title:
- BV(RI)c bands of Cepheids in IC 1613
- Short Name:
- J/A+A/445/901
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A set of six BV(RI)c observations collected with the WFI at the ESO 2.2m telescope have been used to derive multicolor data of Cepheids in IC 1613 identified in previous surveys. Since part of the previously known data were obtained only in V,I filters or without filter (Wh) bands, the method of Freedman has been applied to get reliable mean intensity values of Cepheid magnitudes in the various bands. The resulting slopes of the relations in the BVI bands are similar, within the uncertainties, to those previously obtained by other authors for the LMC. The distribution of the Cepheids in the period-color diagrams is compatible with a change near P about 10d as observed in LMC. The distribution in the color-color diagrams is more similar to that in SMC, and this should be related to the very low metallicity of the galaxy.
- ID:
- ivo://CDS.VizieR/J/other/BASI/30.911
- Title:
- BVRI CCD photometry of 4 galaxy clusters
- Short Name:
- J/other/BASI/30.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the 2.3-meter Vainu Bappu Telescope to perform CCD imaging of X-ray-selected poor clusters of galaxies. Our sample consists of four X-ray luminous clusters in the Einstein Observatory Extended Medium Sensitivity Survey (EMSS) and noted by Gioia & Luppino (1994ApJS...94..583G) to be optically less rich than Abell clusters. The sample spans a redshift range of 0.08<=z<=0.22. We have assembled catalogs of galaxies detected in the cluster fields to a magnitude limit m_V_~22. This paper describes the data reduction performed on the CCD images, the methods used to construct the extended object catalogs, the photometric calibrations, and some understanding of their completeness and contamination.
- ID:
- ivo://CDS.VizieR/J/A+A/376/144
- Title:
- BV(RI)_C_H{alpha} photometry of NGC 663
- Short Name:
- J/A+A/376/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new BV(RI)_C_H{alpha} photometry of the young open cluster NGC 663. The H{alpha} photometry is complete down to magnitude R_C_=15.4, corresponding to spectral type A5 for the cluster members. This allows detection of mild and strong H{alpha} emission in all B-type stars in the cluster. In addition to the 22 Be stars known in the observed field of NGC 663, we discovered four new faint stars of this type. We find that Be stars in NGC 663 cover the whole range of the B spectral type. They are, however, most populous among stars with spectral types falling in the range between B0 and B3, where their fraction amounts to 31+/-8%. Among B-type stars later than B3, Be stars are much less abundant: only 7 out of 101 observed stars, that is, 7+/-3%, were detected. About 70% of the observed Be stars in NGC 663 show detectable variations of light. In the time interval covered by our observations, the ranges of the largest variations reach 0.4mag in the I_C_ band. By means of the isochrone fitting, we derived the cluster distance of 2.1kpc, age of 20-25Myr, and the mean colour excess E(R-I)_C_=0.54mag, with a ~0.1mag scatter due to differential reddening.
- ID:
- ivo://CDS.VizieR/J/AJ/123/304
- Title:
- BV(RI)_C_JHK H{alpha} photometry in IC 5146
- Short Name:
- J/AJ/123/304
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The B0V star BD+46 3474 lies near the front surface of a dense molecular cloud and illuminates the emission/reflection nebula IC 5146. The HAeBe variable BD +46 3471 is embedded in the same cloud, about 10' (3.5pc) away. CCD photometry in BV(RI)_C_ (to V=22) and in JHK (to about K=16.5) has been obtained for the young clusters surrounding each of these two bright stars. Some 100 emission-H{alpha} stars brighter than R=20.5 have been found in the area, most of them in IC 5146. (Among these are two that have spectra resembling a high-excitation Herbig-Haro [HH] object plus a stellar continuum).
- ID:
- ivo://CDS.VizieR/J/PAZh/30/243
- Title:
- BV(RI)c-JHK photometry of BL Lac in 1999-2001
- Short Name:
- J/PAZh/30/243
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of multicolor observations of BL Lac in 1999-2001 are presented. We show that the spectral energy distribution of the variable component in the range from K to B had remained unchanged for three years.
- ID:
- ivo://CDS.VizieR/J/MNRAS/386/521
- Title:
- BV(RI)c light curves of BS Com
- Short Name:
- J/MNRAS/386/521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the basic physical parameters of the field double-mode RR Lyrae star BS Com from its observed periods and the requirement of consistency between the pulsational and evolutionary constraints. We performed a standard frequency analysis on the V data by discrete Fourier transformation. We derived P0=0.48791d and P1=0.36307d for the periods of the fundamental and the first overtone modes, respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/152/219
- Title:
- BV(RI)c light curves of DD Indi
- Short Name:
- J/AJ/152/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations and a 2015 Wilson-Devinney Program analysis are undertaken for the first precision observations of DD Indi. DD Indi is of solar-type (T_1_~5750K) and was determined to be a shallow-contact eclipsing binary. It was observed from 2013 June through September at Cerro Tololo InterAmerican Observatory in remote mode. The 24 inch Boller and Chivens reflector, now under management by The Southeastern Association for Resarch in Astronomy (SARA) was used. Five new eclipse timings were obtained, for three primary and two secondary eclipses. Seven more eclipse timings were calculated from All Sky Automated Survey data. A possibly increasing period was found from all available eclipse timings with a 5+/-2x10^-11^xE^2^ quadratic term. A BVR_c_I_c_ simultaneous synthetic light-curve analysis reveals that the system has a mass ratio of ~0.46, a ~140K component temperature difference, and two weak cool spots. The Roche Lobe fill-out of this W-type binary is only ~11%, and an inclination of ~86{deg} was determined. A time of constant light of ~16 minutes is measured around phase zero. More detail is included in this report.
- ID:
- ivo://CDS.VizieR/J/AJ/152/199
- Title:
- BV(RI)c light curves of FF Vul
- Short Name:
- J/AJ/152/199
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-precision BVR_c_I_c_ light curves of FF Vul were taken during the fall of 2015 with the Dark Sky Observatory 0.81m reflector of Appalachian State University, and the SARA north 0.91m reflector at KPNO. FF Vul is an eclipsing binary with a period of 0.44 day. A Wilson-Devinney solution shows that the binary is a near-contact, semidetached binary, i.e., with a V1010 Oph-type configuration. Five eclipse timings (three primary and two secondary) were calculated. A quadratic ephemeris was determined indicating that the period is decreasing. A near-equatorial hot spot was modeled on the cooler, secondary star, possibly caused by matter impacting from the primary component via the inner Lagrangian point. The component temperature difference is more than 1500K. The solution confirms a total secondary eclipse of 23 minutes duration. As expected in binaries of this type, there is a magnetic spot region.
