Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/140/1500
- Title:
- RR Lyrae variables in the central region of M54
- Short Name:
- J/AJ/140/1500
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analyzed archival Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) observations of the central region of the globular cluster M54. The 12 irregularly timed observations (6 F555W, 6 F814W) were reduced using the HSTphot stellar photometry package. Our statistical analysis of the HSTphot photometry yielded 50 variable stars that are likely RR Lyrae candidates. These candidates were missed by previous ground-based searches for RR Lyraes due to the extreme crowding in the core of M54. We performed two checks on our sample of RR Lyrae candidates to determine how different they were from the other variable candidates.
- ID:
- ivo://CDS.VizieR/J/ApJ/861/23
- Title:
- RR Lyrae variables in the Crater II dwarf galaxy
- Short Name:
- J/ApJ/861/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of RR Lyrae variable stars in Crater II, a recently discovered large and diffuse satellite dwarf galaxy of the Milky Way (MW). Based on B, V time-series photometry obtained with the Korea Microlensing Telescope Network 1.6m telescope at Cerro Tololo Inter-American Observatory, we identified 83 ab-type and 13 c-type pulsators by fitting template light curves. The detected RR Lyrae stars are centrally concentrated, which ensures that most of them are members of Crater II. In terms of the distribution of RRab stars in the period-amplitude diagram, Crater II is clearly different from ultra-faint dwarf (UFD) galaxies, but very similar to the two classical MW dwarf spheroidal (dSph) galaxies Draco and Carina with Oosterhoff-intermediate (Oo-int) properties. Combined with the mean period of ab-type variables (<P_ab_>=0.631+/-0.004days) and the c-type fraction (~0.14) in Crater II, this suggests an Oo-int classification for Crater II and implies that its nature is more like a dSph rather than a UFD. We also estimated the mean metallicity, reddening, and distance of Crater II, from the photometric and pulsation properties of the RR Lyrae stars. The stellar population model we have constructed indicates that Crater II is dominated by an old population, but is relatively younger than the oldest globular clusters in the MW. With a lack of high-amplitude short-period RRab stars, Crater II, like most of the other less massive dSphs, is probably not a surviving counterpart of the major building blocks of the MW halo.
- ID:
- ivo://CDS.VizieR/J/A+A/625/A1
- Title:
- RR Lyrae variables NIR light-curve templates
- Short Name:
- J/A+A/625/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide homogeneous optical (UBVRI) and near-infrared (NIR, JHK) time series photometry for 254 cluster (omega Cen, M4) and field RR Lyrae (RRL) variables. We ended up with more than 551000 measurements. For 94 fundamental (RRab) and 51 first overtones (RRc) we provide a complete optical/NIR characterization (mean magnitudes, luminosity amplitudes, epoch of the anchor point). The NIR light curves of these variables were adopted to provide new light-curve templates for both RRc and RRab variables. The templates for the J and the H bands are newly introduced, together with the use of the pulsation period to discriminate among the different RRab templates. To overcome uncertainties in the fit of secondary features of the light curves we provide two independent sets of analytical functions (Fourier and periodic Gaussian series).
5705. RR Lyrae V light curves
- ID:
- ivo://CDS.VizieR/J/AJ/115/193
- Title:
- RR Lyrae V light curves
- Short Name:
- J/AJ/115/193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I present V-band CCD photometry for a sample of 103 RR Lyrae variables selected from the General Catalogue of Variable Stars to lie in the inner halo of the Galaxy. I also describe a method for obtaining the mean apparent magnitude and the epoch at maximum light of an RR Lyrae star. The method requires as few as five photometric observations, and simulations demonstrate that the associated errors are relatively small. I employ this method to derive the mean magnitudes and maximum light epochs of the 103 RR Lyrae stars observed. These stars were selected, based on their Galactic coordinates and original photographic photometry, to lie near their orbital tangent points, thus providing a sample well suited for measuring the rotational kinematics of the inner halo. Using interstellar reddenings from the literature and the observed mean V magnitudes, I derive distances for these stars and show that their actual locations in the Galaxy are indeed suitable for use in a kinematic study, despite the large zero-point errors in the survey photographic photometry.
5706. RR Lyr in M68
- ID:
- ivo://CDS.VizieR/J/ApJ/412/183
- Title:
- RR Lyr in M68
- Short Name:
- J/ApJ/412/183
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/50.307
- Title:
- RR Lyr light curves in NGC 3201
- Short Name:
- J/other/RMxAA/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD time-series observations of the central region of the globular cluster NGC 3201 were obtained with the aim of performing the Fourier decomposition of the light curves of the RR Lyrae stars present in that field. This procedure gave the mean values, for the metallicity, of [Fe/H]_ZW_=-1.483+/-0.006 (statistical) +/-0.090 (systematical), and for the distance, 5.000+/-0.001kpc (statistical) +/-0.220 (systematical). The values found from two RRc stars are consistent with those derived previously. The differential reddening of the cluster was investigated and individual reddenings for the RR Lyrae stars were estimated from their V-I curves. We found an average value of E(B-V)=0.23+/-0.02. An investigation of the light curves of stars in the blue stragglers region led to the discovery of three new SX Phe stars. The period-luminosity relation of the SX Phe stars was used for an independent determination of the distance to the cluster and of the individual reddenings. We found a distance of 5.0kpc
- ID:
- ivo://CDS.VizieR/J/MNRAS/441/1230
- Title:
- RRLyr stars in the Catalina Sky Survey (CS2)
- Short Name:
- J/MNRAS/441/1230
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of RR Lyrae stars distributed across ~14000deg^2^ of the sky from the combined data of the Sloan Digital Sky Survey (SDSS, http://www.sdss.org), the Panoramic Survey Telescope and Rapid Response System 1 (PS1, Kaiser et al., 2002, SPIE, 4836, 154), and the second photometric catalogue from the Catalina Survey (CS2, http://nesssi.cacr.caltech.edu/DataRelease), out of these, ~2021 RRL stars (~572 RRab and 1449 RRc) are new discoveries. The RRL stars have heliocentric distances in the 4-28kpc distance range. Our catalog has a completeness level of ~50 per cent for both RRab and RRc stars, and an efficiency of ~99 and ~87 per cent for RRab and RRc stars, respectively. We provide the positions, CSDR2 mean magnitudes, CSDR2 amplitudes, subtypes, periods, ephemeris, and the heliocentric distances of our RRab and RRc stars.
- ID:
- ivo://CDS.VizieR/J/A+A/539/A138
- Title:
- RR Lyr variable stars in M32
- Short Name:
- J/A+A/539/A138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using archival multi-epoch ACS/WFC images in the F606W and F814W filters of a resolved stellar field in Local Group dwarf elliptical galaxy M 32 we have made an accurate Colour-Magnitude Diagram and a careful search for RR Lyr variable stars. We identified 416 bona fide RR Lyr stars over our field of view, and their spatial distribution shows a rising number density towards the centre of M 32. These new observations clearly confirm the tentative result of Fiorentino et al. (2010ApJ...708..817F), on a much smaller field of view, associating an ancient population of RR Lyr variables to M 32. We associate at least 83 RR Lyr stars in our field to M 32.
- ID:
- ivo://CDS.VizieR/J/A+A/452/503
- Title:
- RR Tel JHKL photometry 1975-2002
- Short Name:
- J/A+A/452/503
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A set of photometric observations of the symbiotic nova RR Tel in different wavelength bands - visual from 1949 to 2002 and near-infrared (JHKL) from 1975 to 2002 - are presented. Near-infrared photometry is used to identify and study three periods during which the Mira component was heavily obscured by dust. The variability due to the normal Mira pulsation was removed from the JHKL data, which were then compared with the AAVSO visual light curve. We discuss these obscuration events as observed in the different wavelength bands. A change in the colour trend was observed with the colour becoming redder after JD2446000. Generally J-K was comparable while K-L was larger than typical values for solitary Miras. A distance estimate of 2.5kpc, based on the IR data, is given. A study of the behaviour of the permitted Fe II and forbidden [FeII] emission lines during the 1996-2000 obscuration episode suggests a larger flux decrease for the permitted than for the forbidden lines. No other correlation with line properties have been found. The most attractive model involves obscuration by optically thick clouds in the outer layers.
