- ID:
- ivo://CDS.VizieR/J/other/NewA/13.133
- Title:
- 2MASS photometry of cataclysmic variables
- Short Name:
- J/other/NewA/13.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spatial distribution, galactic model parameters and luminosity function of cataclysmic variables (CVs) in the solar neighbourhood have been found using distances estimated from the period-luminosity-colours (PLCs) relation of CVs. It can be concluded that exponential function fits better to the observational z-distributions of the whole CVs in the sample, non-magnetic CVs and dwarf novae, while the sech^2^ function is more appropriate for nova-like stars and polars. The vertical scaleheight of CVs is 158+/-14pc for the 2MASS J band limiting apparent magnitude of 15.8. The discrepancies between the theoretical and observational population studies of CVs can be at least partly removed if the sech^2^ density function is used in deriving the galactic model parameters. We estimated the vertical scaleheights of 128+/-20pc and 160+/-5pc for dwarf novae and nova-like stars, respectively. The local space density of CVs is found ~3x10^-5^pc^-3^ which is in agreement with the lower limit of the theoretical predictions. The luminosity function of CVs shows a trend toward higher space density at low luminosity, implying an increase in the number of short-period systems.
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Search Results
- ID:
- ivo://CDS.VizieR/J/other/JAVSO/39.23
- Title:
- Maxima of short period pulsating stars
- Short Name:
- J/other/JAVSO/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper contains times of maxima for 56 short period pulsating stars (primarily RR Lyrae and delta Scuti stars). This represents a portion of the CCD observations received by the AAVSO Short Period Pulsator (SPP) section in 2010 along with some earlier data.
- ID:
- ivo://CDS.VizieR/J/AJ/115/1016
- Title:
- M31B eclipsing binaries and Cepheids
- Short Name:
- J/AJ/115/1016
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have undertaken a long-term project, DIRECT, to obtain the direct distances to two important galaxies in the cosmological distance ladder - M31 and M33 - using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult to detect, DEBs provide us with the potential to determine these distances with an accuracy better than 5%. The extensive photometry obtained in order to detect DEBs provides us with good light curves for the Cepheid variables. These are essential to the parallel project to derive direct Baade-Wesselink distances to Cepheids in M31 and M33. For both Cepheids and eclipsing binaries, the distance estimates will be free of any intermediate steps. As a first step in the DIRECT project, between 1996 September and 1997 January we obtained 36 full nights on the Michigan-Dartmouth-MIT Observatory 1.3m telescope and 45 full/partial nights on the F.L. Whipple Observatory 1.2m telescope to search for DEBs and new Cepheids in the M31 and M33 galaxies. In this paper, first in a series, we present the catalog of variable stars, most of them newly detected, found in the field M31B [({alpha},{delta})=(11.20{deg}, 41.59{deg}), J2000.0]. We have found 85 variable stars: 12 eclipsing binaries, 38 Cepheids, and 35 other periodic, possible long-period or nonperiodic variables. The catalog of variables, as well as their photometry and finding charts, is available via anonymous ftp and the World Wide Web: http://cfa-www.harvard.edu/~kstanek/DIRECT.
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/2702
- Title:
- MC Cepheids, RR Lyrae stars and binaries
- Short Name:
- J/MNRAS/437/2702
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The VISTA near-infrared Y, J, Ks survey of the Magellanic System (VMC) survey is obtaining multi-epoch photometry in the Ks band of the Magellanic System down to a limiting magnitude of Ks~19.3 for individual epoch data. The observations are spaced in time such as to provide optimal sampling of the light curves for RR Lyrae stars and for Cepheids with periods up to 20-30d. We present examples of the Ks-band light curves of Classical Cepheids and RR Lyrae stars we are obtaining from the VMC data and outline the strategy we put in place to measure distances and infer the System three-dimensional geometry from the variable stars. For this purpose, the near-infrared Period-Luminosity, Period-Wesenheit and Period-Luminosity-Colour relations of the system RR Lyrae stars and Cepheids are used. We extensively exploit the catalogues of the Magellanic Clouds' variable stars provided by the EROS-2 and OGLE III/IV microlensing surveys. By combining these surveys, we present the currently widest-area view of the Large Magellanic Cloud as captured by the galaxy Cepheids, RR Lyrae stars and binaries. This reveals the full extent of the main structures (bar/s - spiral arms) that have only been vaguely guessed before. Our work strengthens the case for a detailed study of the Large Magellanic Cloud three-dimensional geometry.
- ID:
- ivo://CDS.VizieR/J/AJ/117/2810
- Title:
- M31C eclipsing binaries and Cepheids
- Short Name:
- J/AJ/117/2810
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We undertook a long-term project, DIRECT, to obtain the direct distances to two important galaxies in the cosmological distance ladder - M31 and M33 - using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult to detect, DEBs provide us with the potential to determine these distances with an accuracy better than 5%. The extensive photometry obtained in order to detect DEBs provides us with good light curves for the Cepheid variables. These are essential to the parallel project to derive direct Baade-Wesselink distances to Cepheids in M31 and M33. For both Cepheids and eclipsing binaries, the distance estimates will be free of any intermediate steps. As a first step in the DIRECT project, between 1996 September and 1997 October we obtained 95 full/partial nights on the F. L. Whipple Observatory 1.2 m telescope and 36 full nights on the Michigan-Dartmouth-MIT 1.3 m telescope to search for DEBs and new Cepheids in the M31 and M33 galaxies. In this third paper in the series, we present the catalog of variable stars, most of them newly detected, found in the field M31C [(RA, DE)=(11.10{deg}, 41.42{deg}), J2000.0]. We have found 115 variable stars: 12 eclipsing binaries, 35 Cepheids, and 68 other periodic, possible long-period or nonperiodic variables. The catalog of variables, as well as their photometry and finding charts, is available via anonymous ftp and the World Wide Web. The complete set of the CCD frames is available upon request.
- ID:
- ivo://CDS.VizieR/J/AJ/145/106
- Title:
- M31 Cepheid disk sample of 1st year of PS1
- Short Name:
- J/AJ/145/106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of Cepheid variable stars towards M31 based on the first year of regular M31 observations of the PS1 survey in the r_P1 and i_P1 filters. We describe the selection procedure for Cepheid variable stars from the overall variable source sample and develop an automatic classification scheme using Fourier decomposition and the location of the instability strip. We find 1440 fundamental mode (classical {delta}) Cep stars, 126 Cepheids in the first overtone mode, and 147 belonging to the Population II types. 296 Cepheids could not be assigned to one of these classes and 354 Cepheids were found in other surveys. These 2009 Cepheids constitute the largest Cepheid sample in M31 known so far and the full catalog is presented in this paper. We briefly describe the properties of our sample in its spatial distribution throughout the M31 galaxy, in its age properties, and we derive an apparent period-luminosity relation (PLR) in our two bands. The Population I Cepheids nicely follow the dust pattern of the M31 disk, whereas the 147 Type II Cepheids are distributed throughout the halo of M31. We outline the time evolution of the star formation in the major ring found previously and find an age gradient. A comparison of our PLR to previous results indicates a curvature term in the PLR.
737. M101 Cepheids
- ID:
- ivo://CDS.VizieR/J/ApJ/508/491
- Title:
- M101 Cepheids
- Short Name:
- J/ApJ/508/491
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the identification of 255 candidate variable stars in a field located some 1.7' from the center of the late-type spiral galaxy M101 = NGC 5457, based on observations made with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. Photometric measurements in the F555W and F814W filters - analyzed independently with the DAOPHOT/ALLFRAME and DoPHOT software suites - have been transformed to the Johnson V and Kron-Cousins I standard magnitude systems. Periods and intensity-averaged mean magnitudes for 61 carefully selected candidate Cepheid variables with periods in the range 10-48 days indicate a reddening-corrected mean distance modulus (m-M)_0_=29.05+/-0.14 (if the true modulus of the Large Magellanic Cloud is 18.50+/-0.10, and if there is no dependence of the period-luminosity relation on metal abundance); results consistent with this are obtained whether or not the sample is expanded to include a larger fraction of the candidates. Applying a metallicity-dependent correction of +0.16+/-0.10mag would increase this estimate to (m-M)_0_= 29.21+/-0.17mag.
- ID:
- ivo://CDS.VizieR/J/ApJ/799/144
- Title:
- M31 Cepheids in near-IR
- Short Name:
- J/ApJ/799/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the largest M31 near-infrared (F110W (close to J band), F160W (H band)) Cepheid sample so far. The sample consists of 371 Cepheids with photometry obtained from the HST PHAT program. The sample of 319 fundamental mode Cepheids, 16 first overtone Cepheids and 36 type II Cepheids, was identified using the median absolute deviation (MAD) outlier rejection method we develop here. This method does not rely on priors and allows us to obtain this clean Cepheid sample without rejecting a large fraction of Cepheids. The obtained Period-Luminosity relations (PLRs) have a very small dispersion, i.e. 0.155mag in F160W, despite using random phased observations. This remarkably small dispersion allows us to determine that the PLRs are significantly better described by a broken slope at ten days than a linear slope. The use of our sample as an anchor to determine the Hubble constant gives a 3.2% larger Hubble constant compared to the Riess et al. (2012ApJ...745..156R, Cat. J/ApJ/745/156) sample.
- ID:
- ivo://CDS.VizieR/J/A+AS/126/401
- Title:
- M 31 Cepheids periods
- Short Name:
- J/A+AS/126/401
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cepheid variables can be used for more than just a distance indicator. Since the age can be determined from the period, they can be used to trace the star formation history of a galaxy. We have identified 130 new Cepheid variable candidates in M 31, particularly along the spiral arm regions in the north-east of the galaxy. These areas had not been searched for Cepheids in the previous study by Baade and collaborators. The contamination of our sample by other types of variables is low (<3%). For V<21, the completeness is =~53%. These Cepheids will be used to explore the star formation history in M 31.
- ID:
- ivo://CDS.VizieR/J/ApJ/745/156
- Title:
- M31 Cepheids with HST/WFC3
- Short Name:
- J/ApJ/745/156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present measurements of 68 classical Cepheids, most detected from the Canada-France-Hawaii Telescope POMME Survey, with periods from 10 to 78 days observed in the near-infrared by the Panchromatic Hubble Andromeda Treasury Program using the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). The combination of HST's resolution and the use of near-infrared measurements provide a dramatic reduction in the dispersion of the period-luminosity relation over the present optical, ground-based data. Even using random phase magnitudes we measure a dispersion of just 0.17mag, implying a dispersion of just 0.12mag for mean magnitudes. The error in the mean for this relation is 1% in distance. Combined with similar observations of Cepheids in other hosts and independent distance determinations, we measure a distance to M31 of {mu}_0_=24.38+/-0.06(statistical)+/-0.03(systematic), 752+/-27kpc, in good agreement with past measurements though with a better, 3% precision here. The result is also in good agreement with independent distance determinations from two detached eclipsing binaries allowing for an independent calibration of the Cepheid luminosities and a determination of the Hubble constant.
