- ID:
- ivo://CDS.VizieR/J/MNRAS/442/844
- Title:
- BVRI light curves of type II-P supernovae
- Short Name:
- J/MNRAS/442/844
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study a sample of 23 Type II plateau supernovae (SNe II-P), all observed with the same set of instruments. Analysis of their photometric evolution confirms that their typical plateau duration is 100 d with little scatter, showing a tendency to get shorter for more energetic SNe. We examine the claimed correlation between the luminosity and the rise time from explosion to plateau. We analyse their spectra, measuring typical ejecta velocities, and confirm that they follow a well-behaved power-law decline. We find indications of high-velocity material in the spectra of six of our SNe. We test different dust-extinction correction methods by asking the following - does the uniformity of the sample increase after the application of a given method? A reasonably behaved underlying distribution should become tighter after correction. No method we tested made a significant improvement.
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Search Results
- 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/133/2696
- Title:
- BVRI light curves of Westerlund 1 stars
- Short Name:
- J/AJ/133/2696
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the first optical variability study of the Westerlund 1 super star cluster in search of massive eclipsing binary systems. A total of 129 new variable stars have been identified, including the discovery of 4 eclipsing binaries that are cluster members, 1 additional candidate, 8 field binaries, 19 field delta Scuti stars, 3 field W UMa eclipsing binaries, 13 other periodic variables, and 81 long-period or nonperiodic variables. These include the known luminous blue variable, the B[e] star, 11 Wolf-Rayet stars, several supergiants, and other reddened stars that are likely members of Westerlund 1. The bright X-ray source corresponding to the Wolf-Rayet star WR 77o (B) is found to be a 3.51 day eclipsing binary. The discovery of a reddened detached eclipsing binary system implies the first identification of main-sequence stars in Westerlund 1.
- ID:
- ivo://CDS.VizieR/J/AJ/149/48
- Title:
- BVRI light curves of ZZ Eri
- Short Name:
- J/AJ/149/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Complete Bessel BVRI light curves of ZZ Eri [2MASSJ04130109-1044545, HV 6280, NSVS 14888164; IRCS position 04:13:01.10-10:44:54.5; V=13.9-14.4-15.0] are observed and analyzed. The system is a southern pre-contact W UMa binary. Its light curve has the appearance of an Algol (EA) light curve, however, it is made up of dwarf solar-type components with a period of only 0.4521days. Our 34year period study yields a sinusoidal fit or an increasing quadratic fit. The sinusoid may indicate that a third body is orbiting the close binary. The lower-limit mass of the third body is near that of the brown dwarf limit (0.095M_{sun}_). Also included is an improved ephemeris, a mass ratio search, and a simultaneous BVRI Wilson-Devinney solution.
- ID:
- ivo://CDS.VizieR/J/AJ/127/3213
- Title:
- BVR imaging survey of nine early-type galaxies
- Short Name:
- J/AJ/127/3213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a BVR imaging survey of nine early-type galaxies previously verified to exist in extremely isolated environments. Our goals are to establish a baseline of morphological and photometric properties for spheroidal systems evolving in extremely low-density environments and to compare these properties with signatures predicted for merged galaxy groups.
- ID:
- ivo://CDS.VizieR/J/ApJS/218/18
- Title:
- 2004-2012 BVRI observations of blazar S5 0716+714
- Short Name:
- J/ApJS/218/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present long-term optical multi-band photometric monitoring of blazar S5 0716+714, from 2004 January 11 to 2012 November 4, with high temporal resolution of approximately 15 minutes in the BVRI bands. The source was in an active state during the whole monitoring campaign, showing intraday variability in 11 of 72 days. The average magnitudes in each band were B=14.398, V=13.821, R=13.255, and I=12.885. The overall variability amplitudes were {Delta}B=1^m^.834, , {Delta}V=2^m^.167, {Delta}R=2^m^.148, and {Delta}I=1^m^.912. The structure function showed that typical timescales for intraday variability were between approximately 2 and 7.5hr. The intraday variability amplitudes were from a few percent to approximately 30%. We found typical variation rates of approximately 0.05 mag/hr in both the rising and falling phases, with a minimal variability timescale of 130 minutes. A 10 day period short-term variability was observed simultaneously in the BVRI bands. The discrete correlation function suggests that there is significant correlated variability between the B- and I-band light curves. However, no significant time lags were detected. The spectral behaviors in the different variability episodes were studied, and our observations show bluer-when-brighter behavior on long, short, and intraday timescales for the blazar S5 0716+714. The variability and relevant spectral trends can be explained by the shock-in-jet scenario.
- ID:
- ivo://CDS.VizieR/J/AJ/155/31
- Title:
- 2005-2012 BVRI observations of blazar S5 0716+714
- Short Name:
- J/AJ/155/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to search for the evidence of quasi-periodic oscillation (QPO) in blazars, multicolor optical observations of the BL Lacertae object S5 0716+714 were performed from 2005 to 2012. For I band observations on 2010 March 19 with low variability amplitude and low flux level, the same QPO~50 minutes at the 99% significance level is confirmed by the ZDCF method, Lomb-Scargle method, REDFIT, and fitting sinusoidal curves. The observed QPO is likely to be explained by accretion disk variability. If the observed QPO indicates an innermost stable orbital period from the accretion disk, the QPO~50 minutes corresponds to a black hole mass of 5.03x10^6^ M_{sun}_ for a non-rotating Schwarzschild black hole and 3.2x10^7^ M_{sun}_ for a maximally rotating Kerr black hole.
- 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/ApJS/142/71
- Title:
- BVRI observations of LMC Cepheids
- Short Name:
- J/ApJS/142/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A homogeneous set of ground-based BVRI observations of ~600 Cepheids is presented to check the Cepheid period-luminosity (PL) zero point for the Large Magellanic Cloud (LMC). The sample of Cepheids is completely self-contained and has been reduced consistently to eliminate photometric differences caused by combining multiple sources of photometry. The Cepheid distances to nearby galaxies obtained by the Hubble Space Telescope (HST) Key Project on the Extragalactic Distance Scale were computed assuming a "standard" PL relation based on a compilation of photoelectric observations of 34 Cepheids and a standard distance modulus to the LMC of 18.50. The final Key Project results substituted a statistically stronger PL relation obtained by the OGLE collaboration. In this paper we compare our data with the OGLE PL relation; the subsample of LMC Cepheids with similar periods to those discovered in the nearby galaxies is fainter at the relevant periods by 0.04+/-0.02mag than the OGLE sample. Substituting in turn this PL relation for that of the OGLE collaboration would raise the Hubble constant by 2%+/-1%, a correction which is not significant. The multicolor data set will also be useful in considering the effects of reddening and chemical composition and deriving an improved Cepheid period-luminosity relation for the LMC.
- ID:
- ivo://CDS.VizieR/J/A+A/556/A60
- Title:
- BVRI observations of the FUor star V582 Aur
- Short Name:
- J/A+A/556/A60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from optical photometric and spectroscopic observations of the eruptive pre-main sequence star V582 Aur. Variability of the star was reported a few years ago when it was suspected as a possible FU Orionis object. Due to the small number of currently known FUors, a new object of this type is ideal target for follow-up photometric and spectroscopic observations. We carried out BVRI CCD photometric observations in the field of V582 Aur from 2009 August to 2013 April. We acquired high-, medium-, and low-resolution spectroscopy of V582 Aur during this period. To study the pre-outburst variability of the target and construct its historical light curve, we searched for archival observations in photographic plate collections. The pre-outburst photographic observations of V582 Aur show low-amplitude light variations typical of T Tauri stars. Archival photographic observations indicate that the increase in brightness began in late 1984 or early 1985 and the star reached the maximum level of brightness at 1986 January. Our BVRI photometric observations show large amplitude variations ({Delta}V~2.8mag.) during the 3.5 year period of observations. Most of the time, however, the star remains in a state close to the maximum brightness. The deepest drop in brightness was observed in the spring of 2012, when the brightness of the star fell to a level close to the pre-outburst. The multicolor photometric data show a color reversal during the minimum in brightness, which is typical of UX Ori variables.