- ID:
- ivo://CDS.VizieR/J/A+A/468/1039
- Title:
- VRIJK photometry of GQ Lup
- Short Name:
- J/A+A/468/1039
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We wanted to determine the rotation parameters of GQ Lup A, thereby constraining the evolutionary history of the GQ Lup system. We have undertaken a photometric monitoring campaign on GQ Lup A consisting of two epochs spaced one year apart. We also searched the photometric archives to enlarge the data set.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/222/24
- Title:
- VRI LCs of BL Lac object Mrk 501 from 2010 to 2015
- Short Name:
- J/ApJS/222/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have monitored the BL Lac object Mrk 501 in the optical V, R, and I bands from 2010 to 2015. For Mrk 501, the presence of a strong host galaxy component can affect the results of photometry. After subtracting the host galaxy contributions, the source shows intraday and long-term variabilities for optical flux and color indices. The average variability amplitudes of the V, R, and I bands are 22.05%, 22.25%, and 23.82%, respectively, and the value of the duty cycle is 14.87%. A minimal variability timescale of 106 minutes is detected. No significant time lag between the V and I bands is found on one night. The bluer-when-brighter (BWB) trend is dominant for Mrk 501 on intermediate, short, and intraday timescales, which supports the shock-in-jet model. For the long timescale, Mrk 501, in different states, can have different BWB trends. The corresponding results for non-correcting host galaxy contributions are also presented. We have monitored the BL Lac object Mrk 501 in the optical V, R, and I bands from 2010 to 2015. For Mrk 501, the presence of a strong host galaxy component can affect the results of photometry. After subtracting the host galaxy contributions, the source shows intraday and long-term variabilities for optical flux and color indices. The average variability amplitudes of the V, R, and I bands are 22.05%, 22.25%, and 23.82%, respectively, and the value of the duty cycle is 14.87%. A minimal variability timescale of 106 minutes is detected. No significant time lag between the V and I bands is found on one night. The bluer-when-brighter (BWB) trend is dominant for Mrk 501 on intermediate, short, and intraday timescales, which supports the shock-in-jet model. For the long timescale, Mrk 501, in different states, can have different BWB trends. The corresponding results for non-correcting host galaxy contributions are also presented.
- ID:
- ivo://CDS.VizieR/J/MNRAS/442/2620
- Title:
- VRI light curve of 5 eclipsing binaries
- Short Name:
- J/MNRAS/442/2620
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report 15 new VRI light curves of five low-mass eclipsing binaries (NSVS 02502726, NSVS 07453183, NSVS 11868841, NSVS 06550671 and NSVS 10653195) that were observed between 2010 and 2012. We analysed our new data together with three published spectroscopic observations and seven published light curves using a modified version of the Wilson-Devinney program. Orbital solutions of the five low-mass eclipsing binaries were revised and new star-spot parameters were obtained. We found that spot locations on the five low-mass eclipsing binaries changed over several years. However, the star-spots for NSVS 07453183 and NSVS 06550671 were stable for several months. More interestingly, for NSVS 02502726, the spots within a star-spot longitude region of 180{deg}-360{deg} indicated a magnetic activity cycle of 5.9(+/-0.2)yr. Moreover, we detected the first flare-like event on NSVS 07453183 at phase 0.39. The observations of the chromospheric activity indicators (H{beta} and H{gamma} lines) revealed that NSVS 10653195 and NSVS 06550671 were active. For NSVS 02502726, we found a weak continuous secular decrease at a smaller rate of dp/dt=-2.1(0.8)x10^-7^d/yr than the previous result. For NSVS 07453183, the O-C times appeared to increase at cycle 6000, and this was followed by a decrease at cycle 6500.
- ID:
- ivo://CDS.VizieR/J/AJ/152/57
- Title:
- VRI light curves of four contact binaries
- Short Name:
- J/AJ/152/57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new, high-quality multicolor observations of four recently discovered contact binaries, 1SWASP J064501.21+342154.9, 1SWASP J155822.10-025604.8, 1SWASP J212808.86+151622.0, and UCAC4 436-062932, and analyze their light curves to determine orbital and physical parameters using the modeling program of G. Djurasevic. In the absence of spectroscopic observations, the effective temperatures of the brighter components are estimated from the color indices, and the mass ratios are determined with the q-search method. The analysis shows that all four systems are W UMa type binaries in shallow contact configurations, consisting of late-type main-sequence primaries and evolved secondaries with active surface regions (dark or bright spots) resulting from magnetic activity or ongoing transfer of thermal energy between the components. We compare the derived orbital and stellar parameters for these four variables with a large sample of previously analyzed W UMa stars and find that our results fit it well.
- ID:
- ivo://CDS.VizieR/J/AJ/150/9
- Title:
- VRI light curves of GSC 1537-1557
- Short Name:
- J/AJ/150/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- By analyzing R_c_ and I_c_light curves of the short-period solar-type eclipsing binary GSC 1537-1557 we discovered that it is a shallow contact binary with a degree of contact factor of f=(8.1+/-1.79)%. Photometric solutions reveal that GSC 1537-1557 is a W-type system with a mass ratio of q=M_2_/M_1_=2.645 where the less massive component (the primary star) is about 110K hotter than the more massive one (the secondary star). The asymmetry and variation of the light curves were explained as the activity of spots on the solar-type component stars. By investigating all of the available times of light minima, we found that the observed-calculated (O-C) curve shows a cyclic variation with a small amplitude of 0.00335days and a period of 8.1years. The small-amplitude cyclic change in the O -C curve was analyzed for the light-travel time effect via the presence of an extremely cool stellar companion. The mass of the third body was determined to be M_3_sini'=(0.19+/-0.01)M_{sun}_ when M_1_+M_2_=1.31M_{sun}_ is adopted for GSC 1537-1557. The semimajor axis of the outer obit is a'sini'=(4.58+/-0.33)AU.
- ID:
- ivo://CDS.VizieR/J/ApJ/783/35
- Title:
- VRI light curves of TT Her
- Short Name:
- J/ApJ/783/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new radial velocities and photometry of the short-period Algol TT Herculis. Previous attempts to model the light curves of the system have met with limited success, primarily because of the lack of a reliable mass ratio. Our spectroscopic observations are the first to result in radial velocities for the secondary star, and thus provide a spectroscopic mass ratio. Simultaneous analysis of the radial velocities and new photometry shows that the system is a double contact binary, with a rapidly rotating primary that fills its limiting lobe.
- ID:
- ivo://CDS.VizieR/J/ApJS/229/21
- Title:
- VRI monitoring of the QSO 3C 273 in 2005-2016
- Short Name:
- J/ApJS/229/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have monitored the quasar 3C 273 in the optical V, R, and I bands from 2005 to 2016. Intraday variability (IDV) is detected on seven nights. The variability amplitudes on most of the nights are less than 10%, and on four nights, more than 20%. When considering the nights with time spans >4hr, the duty cycle (DC) is 14.17%. Over the 12yrs, the overall magnitude and color index variabilities are {Delta}I=0.67, {Delta}R=0.72, {Delta}V=0.68, and {Delta}(V-R)=0.25, respectively. The largest clear IDV has an amplitude of 42% over just 5.8 minutes, and the weakest detected IDV is 5.4% over 175 minutes. The BWB (bluer when brighter) chromatic trend is dominant for 3C 273 and appears at different flux levels on intraday timescales. The BWB trend exists for short-term timescales and intermediate-term timescales but different timescales have different correlations. There is no BWB trend for our whole time-series data sets. A significant anticorrelation between the BWB trend and length of timescales is found. Combining with V-band data from previous works, we find a possible quasi-periodicity of P=3918+/-1112 days. The possible explanations for the observed variability, BWB chromatic trend, and periodicity are discussed.
- ID:
- ivo://CDS.VizieR/J/AJ/128/846
- Title:
- VRI observations of CE Leonis
- Short Name:
- J/AJ/128/846
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present complete VRI light curves of the contact binary CE Leo and provide detailed photometric solutions, as well as an analysis of its period variation. A total of 73 times of minima over 50years, including our observations, were used for the period study.
- ID:
- ivo://CDS.VizieR/J/AZh/84/885
- Title:
- VRI observations of radio source S5 0716+71
- Short Name:
- J/AZh/84/885
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of VRI photometry of the gravitationally lensed system Q2237+0305 carried out on the 1.5-m telescope of Maidanak observatory in 2004-2005 are presented. The distance between the components is of the order of 1".
- ID:
- ivo://CDS.VizieR/J/ApJ/669/525
- Title:
- VRI photometric standards for NGC 6946
- Short Name:
- J/ApJ/669/525
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new, very late time optical photometry and spectroscopy of the interesting Type II-P supernova SN 2002hh, in NGC 6946. Gemini/GMOS-N has been used to acquire visible spectra at six epochs between 2004 August and 2006 July, following the evolution of the SN from age 661 to 1358-days. Few optical spectra of Type II supernovae with ages greater than 1yr exist. In addition, g', r', and i' images were acquired at all six epochs. The spectral and photometric evolution of SN 2002hh has been very unusual. Measures of the brightness of this SN, both in the R and I bands, as well as in the Halpha emission flux, show no significant fading over an interval of nearly 2-years.
