- ID:
- ivo://CDS.VizieR/J/ApJ/783/83
- Title:
- BVRI photometry of S5 0716+714
- Short Name:
- J/ApJ/783/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- S5 0716+714 is a typical BL Lacertae object. In this paper we present the analysis and results of long-term simultaneous observations in the radio, near-infrared, optical, X-ray, and {gamma}-ray bands, together with our own photometric observations for this source. The light curves show that the variability amplitudes in {gamma}-ray and optical bands are larger than those in the hard X-ray and radio bands and that the spectral energy distribution (SED) peaks move to shorter wavelengths when the source becomes brighter, which is similar to other blazars, i.e., more variable at wavelengths shorter than the SED peak frequencies. Analysis shows that the characteristic variability timescales in the 14.5GHz, the optical, the X-ray, and the {gamma}-ray bands are comparable to each other. The variations of the hard X-ray and 14.5GHz emissions are correlated with zero lag, and so are the V band and {gamma}-ray variations, which are consistent with the leptonic models. Coincidences of {gamma}-ray and optical flares with a dramatic change of the optical polarization are detected. Hadronic models do not have the same natural explanation for these observations as the leptonic models. A strong optical flare correlating a {gamma}-ray flare whose peak flux is lower than the average flux is detected. The leptonic model can explain this variability phenomenon through simultaneous SED modeling. Different leptonic models are distinguished by average SED modeling. The synchrotron plus synchrotron self-Compton (SSC) model is ruled out because of the extreme input parameters. Scattering of external seed photons, such as the hot-dust or broad-line region emission, and the SSC process are probably both needed to explain the {gamma}-ray emission of S5 0716+714.
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- ID:
- ivo://CDS.VizieR/J/AJ/119/777
- Title:
- BVRI photometry of Sagittarius dwarf irregular galaxy
- Short Name:
- J/AJ/119/777
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep BVRI CCD photometry of the stars in the dwarf irregular galaxy SagDIG, obtained on the photometric night of 1994 October 8 (UT) using the University of Hawaii 2.2 m telescope at Mauna Kea.
- ID:
- ivo://CDS.VizieR/J/AJ/154/42
- Title:
- BVRI photometry of S5 0716+714 in 2012
- Short Name:
- J/AJ/154/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We monitored the BL Lacertae object S5 0716+714 in the optical bands during 2012 January and February with long time spans on intraday timescales (>5hr) and high time resolutions. During this monitoring period, the object shows violent flaring activity in both short and intraday timescales. The object has a high duty cycle. The light curves detected as intraday variability show variability of various shapes. The variability amplitude is from 12.81% to 33.22%, and the average value is 19.92%+/-5.87%. The overall magnitude variabilities are {Delta}B=1.24^m^, {Delta}V=1.42^m^, {Delta}R=1.3^m^, and {Delta}I=1.23^m^. During the observations, the average change rate is <CR>{=}0.035+/-0.009Mag/h during the ascent and <CR>{=}0.035+/-0.014Mag/h during the descent. However, different cases are found on certain nights. There are good interband correlations but no significant time lags for intraday and short timescales. The results of the autocorrelation function show that the variability timescales range from 0.054 to 0.134 day. Most nights show a bluer-when-brighter (BWB) chromatic trend, a weak redder-when-brighter (RWB) trend is found, and a few nights show no correlation between magnitude and color index. The BWB trend appears in short timescales. During the flare, the spectral index exhibits a clockwise loop for internights. A shock-in-jet model and the shock wave propagating along a helical path are likely to explain the variability and color index variability.
- ID:
- ivo://CDS.VizieR/J/other/Obs/116.382
- Title:
- BVRI Photometry of Spectroscopic Binaries
- Short Name:
- J/other/Obs/116.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BVRI photometry has been obtained for 82 of the spectroscopic binaries with orbits published in The Observatory by Griffin and his collaborators. The observations were obtained on nineteen nights during 1994-95. Given here are the star name, Griffin's paper number for the spectroscopic orbit, the abbreviated calendar date and heliocentric Julian Date (HJD) of the observation, the derived V, (B-V), (V-R)c, and (R-I)c values, and the phase in the spectroscopic orbit. The mean photometric values are listed in the final entry for each star. One night of poor quality, 950128, was given half weight in forming the means. The rms error of a single observation is about 0.025 mag. for all indices.
- ID:
- ivo://CDS.VizieR/J/other/IBVS/5526
- Title:
- BVRI photometry of stars in BZ UMa field
- Short Name:
- J/other/IBVS/552
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The AAVSO has received 4270 CCD measurements of BZ UMa over four nights during its March, 2004 outburst. Analysis of the measurements reveals rapid flickering and quasiperiodic behaviour but no coherent periodicity (beyond the orbital period) and the notable absence of superhumps
- ID:
- ivo://CDS.VizieR/J/ApJ/764/114
- Title:
- BVRI photometry of stars in Orion A
- Short Name:
- J/ApJ/764/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extend our previous study of the stellar population of L1641, the lower-density star-forming region of the Orion A cloud south of the dense Orion Nebula Cluster (ONC), with the goal of testing whether there is a statistically significant deficiency of high-mass stars in low-density regions. Previously, we compared the observed ratio of low-mass stars to high-mass stars with theoretical models of the stellar initial mass function (IMF) to infer a deficiency of the highest-mass stars in L1641. We expand our population study to identify the intermediate-mass (late B to G) L1641 members in an attempt to make a more direct comparison with the mass function of the nearby ONC. The spectral-type distribution and the K-band luminosity function of L1641 are similar to those of the ONC, but problems of incompleteness and contamination prevent us from making a detailed test for differences. We limit our analysis to statistical tests of the ratio of high-mass to low-mass stars, which indicate a probability of only 3% that the ONC and the southern region of L1641 were drawn from the same population, supporting the hypothesis that the upper-mass end of the IMF is dependent on environmental density.
- ID:
- ivo://CDS.VizieR/J/PASP/114/1382
- Title:
- BVRI photometry of Stock 1 stars
- Short Name:
- J/PASP/114/1382
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BVRI photometry and J2000.0 positions have been obtained for stars in the field of the open cluster Stock 1. The photometry has been combined with available spectral types and proper motions to investigate cluster membership. We conclude that Stock 1 is a young cluster with a reddening of E(B-V)=0.16+/-0.04, a distance modulus of V_0_-M_V_=7.5+/-0.1, and an age of 300+/-50Myr.
- ID:
- ivo://CDS.VizieR/J/AJ/144/37
- Title:
- BVRI photometry of the eclipsing binary BS Vul
- Short Name:
- J/AJ/144/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed study of the close eclipsing binary BS Vulpeculae. Although it is relatively bright (V: 10.9-11.6mag) and belongs to short-periodic variable stars (P=0.48days), it is rather neglected. To perform a thorough period analysis, we collected all available photometric observations that span the time interval of 1898-2010. Observations include archive photographic plate measurements and visually determined eclipse minima timings done in 1979-2003, which were later shown to be biased to accommodate the existing linear ephemeris. Applying our own direct period analysis we found a well-defined shortening of the orbital period of dP/dt=-6.70(17)x10^-11^=-2.11(6)ms/yr, which implies a continual mass flow from the primary to the secondary component. Using the 2003 version of the Wilson-Van Hamme code, our new complete BV(IR)_C_ light curves were analyzed and the physical parameters of the system were derived. We found that BS Vul is a near contact binary system with the primary component filling its critical Roche lobe. The luminosity enhancement on the left shoulder of the secondary minimum shown in the light curves can be explained as a result of a persistent hot spot on the secondary due to the mass transfer from the primary component to the secondary one and heating the facing hemisphere of the secondary component, which is consistent with our result of period analysis. With the period decrease, BS Vul will evolve toward the contact phase. It is another good observational example as predicted by the theory of thermal relaxation oscillations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/487/832
- Title:
- BVRI photometry of the Type II-P SN 2017eaw
- Short Name:
- J/MNRAS/487/832
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Broadband BVRI light curves of SN 2017eaw in NGC 6946 reveal the classic elements of a Type II-P supernova. The observations were begun on 16 May 2017 (UT), approximately 1 d after the discovery was announced, and the photometric monitoring was carried out over a period of nearly 600d. The light curves show a well-defined plateau and an exponential tail which curves slightly at later times. An approximation to the bolometric light curve is derived and used to estimate the amount of ^56^Ni created in the explosion; from various approaches described in the literature, we obtain M(^56^Ni)=0.115_-0.022_^+0.027^M_{sun}_. We also estimate that 43 per cent of the bolometric flux emitted during the plateau phase is actually produced by the ^56^Ni chain. Other derived parameters support the idea that the progenitor was a red supergiant.
- ID:
- ivo://CDS.VizieR/J/A+A/368/932
- Title:
- BVRI photometry of V367 Cyg
- Short Name:
- J/A+A/368/932
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New BVRI photoelectric observations of the interacting binary V367 Cyg were made during two consecutive seasons, 1996 and 1997, using the two-channel photometer at Mt. Suhora Observatory. Data left in the instrumental system and sorted with time of observations.
