- ID:
- ivo://CDS.VizieR/J/A+A/415/521
- Title:
- BVRIJK and velocities for MC Cepheids
- Short Name:
- J/A+A/415/521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high precision and well sampled BVRIJK light curves and radial velocity curves for a sample of five (+1) Cepheids in the SMC. In addition we present radial velocity curves for five (+1) Cepheids in the LMC. The low metallicity ([Fe/H]~-0.7) SMC stars have been selected for use in a Baade-Wesselink type analysis to constrain the metallicity effect on the Cepheid Period-Luminosity relation. The stars have periods of around 15 days so they are similar to the Cepheids observed by the Extragalactic Distance Scale Key Project on the Hubble Space Telescope. We show that the stars are representative of the SMC Cepheid population at that period and thus will provide a good sample for the proposed analysis. The actual Baade-Wesselink analysis are presented in Strom et al., 2004, Cat. <J/A+A/415/531>.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/788/41
- Title:
- BVRI light curve of OGLE LMC-ECL-11893
- Short Name:
- J/ApJ/788/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the serendipitous discovery of a disk-eclipse system OGLE-LMC-ECL-11893. The eclipse occurs with a period of 468 days, a duration of about 15 days, and a deep (up to {Delta}m_I_~1.5), peculiar, and asymmetric profile. A possible origin of such an eclipse profile involves a circumstellar disk. The presence of the disk is confirmed by the H-alpha line profile from the follow-up spectroscopic observations, and the star is identified as Be/Ae type. Unlike the previously known disk-eclipse candidates, the eclipses of OGLE-LMC-ECL-11893 retain the same shape throughout the span of ~17yr (13 orbital periods), indicating no measurable orbital precession of the disk.
- ID:
- ivo://CDS.VizieR/J/A+A/493/1093
- Title:
- BVRI light curves of {eta} Car
- Short Name:
- J/A+A/493/1093
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The periodicity of 5.5 years for some observational events occurring in {eta} Carinae manifests itself across a large wavelength range and has been associated with its binary nature. These events are supposed to occur when the binary components are close to periastron. To detect the previous periastron passage of {eta} Car in 2003, we started an intensive, ground-based, optical, photometric observing campaign. We continued observing the object to monitor its photometric behavior and variability across the entire orbital cycle. Our observation program consisted of daily differential photometry from CCD images, which were acquired using a 0.8m telescope and a standard BVRI filter set at La Plata Observatory. The photometry includes the central object and the surrounding Homunculus nebula. We present up-to-date results of our observing program, including homogeneous photometric data collected between 2003 and 2008. Our observations demonstrated that {eta} Car has continued increasing in brightness at a constant rate since 1998. In 2006, it reached its brightest magnitude (V~4.7) since about 1860s. The object then suddenly reverted its brightening trend, fading to V=5.0 at the beginning of 2007, and has maintained a quite steady state since then. We continue the photometric monitoring of {eta} Car in anticipation of the next "periastron passage", predicted to occur at the beginning of 2009.
- ID:
- ivo://CDS.VizieR/J/A+A/645/A137
- Title:
- BVRI light curves of PG 1553+113
- Short Name:
- J/A+A/645/A137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The TeV BL Lac object PG 1553+113 is one of the primary candidates for a binary supermassive black hole system. We study the flux and spectral variability of PG 1553+113 on intra-night to long-term timescales using (i) BVRI data collected over 76 nights from January 2016 to August 2019 involving nine optical telescopes and (ii) historical VR data (including ours) obtained for the period from 2005 to 2019. We analysed the light curves using various statistical tests, fitting and cross-correlation techniques, and methods for the search for periodicity. We examined the colour-magnitude diagrams before and after the corresponding light curves were corrected for the long-term variations. Our intra-night monitoring, supplemented with literature data, result in a low duty cycle of ~(10-17)%. In April 2019, we recorded a flare, which marks the brightest state of PG 1553+113 for the period from 2005 to 2019: R~13.2mag. This flare is found to show a clockwise spectral hysteresis loop on its VR colour-magnitude diagram and a time lag in the sense that the V-band variations lead the R-band ones. We obtain estimates of the radius, the magnetic field strength, and the electron energy that characterize the emission region related to the flare. We find a median period of (2.21+/-0.04) years using the historical light curves. In addition, we detect a secondary period of about 210 days using the historical light curves corrected for the long-term variations. We briefly discuss the possible origin of this period.
- ID:
- ivo://CDS.VizieR/J/AJ/136/1846
- Title:
- BVRI light curves of S5 0716+714
- Short Name:
- J/AJ/136/1846
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the optical photometry (B, V, R, and I) of the BL Lac object S5 0716+714 (z>0.3), which were observed with the 1m telescope at Yunnan Astronomical Observatory and the 1.56m telescope at Shanghai Astronomical Observatory from 2001 February to 2006 April.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A11
- Title:
- BVRI light curves of V374 Peg
- Short Name:
- J/A+A/590/A11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ultrafast-rotating (Prot~0.44d) fully convective single M4 dwarf V374 Peg is a well-known laboratory for studying intense stellar activity in a stable magnetic topology. As an observable proxy for the stellar magnetic field, we study the stability of the light curve, hence the spot configuration. We also measure the occurrence rate of flares and coronal mass ejections (CMEs). We have analysed spectroscopic observations, BV(RI)C photometry covering 5yrs, and additional RC photometry that expands the temporal base over 16yr. The light curve suggests an almost rigid-body rotation and a spot configuration that is stable over about 16 yrs, confirming the previous indications of a very stable magnetic field. We observed small changes on a nightly timescale and frequent flaring, including a possible sympathetic flare. The strongest flares seem to be more concentrated around the phase where the light curve indicates a smaller active region. Spectral data suggest a complex CME with falling-back and re-ejected material with a maximal projected velocity of ~675km/s. We observed a CME rate that is much lower than expected from extrapolations of the solar flare-CME relation to active stars.
- ID:
- ivo://CDS.VizieR/J/AJ/138/845
- Title:
- BVRI observations of 235 bright quasars
- Short Name:
- J/AJ/138/845
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric observations of 235 extragalactic objects that are potential targets for the Space Interferometry Mission (SIM) are presented. Mean B, V, R, I magnitudes at the 5% level are obtained at 1-4 epochs between 2005 and 2007 using the 1m telescopes at Cerro Tololo Inter-American Observatory and the Naval Observatory Flagstaff Station. Of the 134 sources that have V magnitudes in the Veron & Veron-Cetty catalog (Cat. VII/248), a difference of over 1.0mag is found for the observed-catalog magnitudes for about 36% of the common sources, and 10 sources show over 3mag difference. Our first set of observations presented here form the basis of a long-term photometric variability study of the selected reference frame sources to assist in mission target selection and to support QSO multicolor photometric variability studies in general.
- ID:
- ivo://CDS.VizieR/J/AJ/142/99
- Title:
- BVRI observations of TZ Boo
- Short Name:
- J/AJ/142/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD photometric BVRI observations of the puzzling W UMa type binary star, TZ Bootis, are presented from our observations in 2010. By using the updated version of the Wilson-Devinney code, the first modern photometric solution is deduced from new photometric observations and published spectroscopic data.
- ID:
- ivo://CDS.VizieR/J/other/Ap/48.304
- Title:
- BVRI of comparison stars in AGN fields
- Short Name:
- J/other/Ap/48.30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results are presented from CCD BVRI-observations of 145 comparison stars in the neighborhoods of 14 Seyfert galaxies, 3 quasars, and 5 BL Lac objects with right ascensions of 12 to 24 hours. The magnitudes of the observed stars ranged from V=11 to V=17. The typical photometric error for stars brighter V=14 is 0.01m. The B, V, Rc, and Ic magnitudes of most of these stars were not known previously. 14'x14' finding charts are provided. These results can be used for differential photometry of the nuclei of active galaxies in the B, V, Rc, and Ic bands.
- ID:
- ivo://CDS.VizieR/J/A+AS/142/425
- Title:
- BVRI photometry of 6 galaxies
- Short Name:
- J/A+AS/142/425
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometry of the brightest stars in six nearby spiral and irregular galaxies with corrected radial velocities from 340 to 460km/s. Three of them are resolved into stars for the first time. Based on luminosity of the brightest blue stars we estimate the following distances to the galaxies: 5.0Mpc for NGC 784, 9.2Mpc for NGC 2683, 8.9Mpc for NGC 2903, 4.1Mpc for NGC 5204, 6.8Mpc for NGC 5474, and 8.7Mpc for NGC 5585.
