- ID:
- ivo://CDS.VizieR/J/AJ/133/1041
- Title:
- Velocities and CMT2 photometry in globular M92
- Short Name:
- J/AJ/133/1041
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the determination of high-accuracy radial velocities for 306 members of the globular cluster M92 using the Hydra multiobject spectrograph on the WIYN telescope. We have concentrated on stars outside of the central region of the cluster, located up to 14.4' from the cluster center. Candidate members were selected for spectroscopy based on a photometric metallicity index determined from three-band Washington photometry, also obtained with the WIYN telescope.
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- ID:
- ivo://CDS.VizieR/J/A+A/464/L21
- Title:
- Velocities of globular clusters in Fornax
- Short Name:
- J/A+A/464/L21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We acquired radial velocities of a significant number of globular clusters (GCs) on wide fields between galaxies in the nearby Fornax cluster of galaxies, in order to derive their velocity dispersion radial profile and to probe the dynamics of the cluster. We used FLAMES on the VLT to obtain accurate velocities for 149 GCs, within a ~500x150kpc strip centered on NGC 1399, the Fornax central galaxy. These objects are at the very bright tail (M_V_<~-9.5) of the GC luminosity function, overlapping the so-called "ultra-compact dwarfs" magnitude range. Eight of the brightest FLAMES-confirmed members indeed show hints of resolution in the subarcsecond pre-imaging data we used for selecting the ~500 targets for FLAMES spectroscopy.
- ID:
- ivo://CDS.VizieR/J/AJ/147/150
- Title:
- Velocities of globular clusters in M104
- Short Name:
- J/AJ/147/150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained radial velocity measurements for 51 new globular clusters around the Sombrero galaxy. These measurements were obtained using spectroscopic observations from the AAOmega spectrograph on the Anglo-Australian Telescope and the Hydra spectrograph at WIYN. Combining our own past measurements and velocity measurements obtained from the literature, we have constructed a large database of radial velocities that contains a total of 360 confirmed globular clusters. Previous studies' analyses of the kinematics and mass profile of the Sombrero globular cluster system have been constrained to the inner ~9' (~24kpc or ~5R_e_), but our new measurements have increased the radial coverage of the data, allowing us to determine the kinematic properties of M104 out to ~15' (~41kpc or ~9R_e_). We use our set of radial velocities to study the GC system kinematics and to determine the mass profile and V-band mass-to-light profile of the galaxy. We find that M/L_V_ increases from 4.5 at the center to a value of 20.9 at 41kpc (~9R_e_ or 15'), which implies that the dark matter halo extends to the edge of our available data set. We compare our mass profile at 20kpc (~4R_e_or ~7.4') to the mass computed from X-ray data and find good agreement. We also use our data to look for rotation in the globular cluster system as a whole, as well as in the red and blue subpopulations. We find no evidence for significant rotation in any of these samples.
- ID:
- ivo://CDS.VizieR/J/A+A/513/A52
- Title:
- Velocities of NGC 1399 globular clusters
- Short Name:
- J/A+A/513/A52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Globular clusters (GCs) are tracers of the gravitational potential of their host galaxies. Moreover, their kinematic properties may provide clues for understanding the formation of GC systems and their host galaxies. We use the largest set of GC velocities obtained so far of any elliptical galaxy to revise and extend the previous investigations (Richtler et al., 2004AJ....127.2094R) of the dynamics of NGC 1399, the central dominant galaxy of the nearby Fornax cluster of galaxies. The GC velocities are used to study the kinematics, their relation with population properties, and the dark matter halo of NGC 1399. We have obtained 477 new medium-resolution spectra (of these, 292 are spectra from 265 individual GCs, 241 of which are not in the previous data set). with the VLT FORS 2 and Gemini South GMOS multi--object spectrographs. We revise velocities for the old spectra and measure velocities for the new spectra, using the same templates to obtain an homogeneously treated data set. Our entire sample now comprises velocities for almost 700 GCs with projected galactocentric radii between 6 and 100kpc. In addition, we use velocities of GCs at larger distances published by Bergond et al. (2007, Cat. J/A+A/464/L21). Combining the kinematic data with wide-field photometric Washington data, we study the kinematics of the metal-poor and metal--rich subpopulations. We discuss in detail the velocity dispersions of subsamples and perform spherical Jeans modelling.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A115
- Title:
- Velocities of NGC 4636 globular clusters
- Short Name:
- J/A+A/544/A115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new radial velocities for 289 globular clusters around NGC 4636, the southernmost giant elliptical galaxy of the Virgo cluster. The data were obtained with FORS2/MXU at the Very Large Telescope. Together with data analysed in an earlier study, we now have a sample of 460 globular cluster velocities out to a radius of 12-arcmin (60kpc) available - one of the largest of its kind. This new data set also provides a much more complete angular coverage. Moreover, we present new kinematical data of the inner stellar population of NGC 4636. We perform an updated Jeans analysis, using both stellar and GC data, to better constrain the dark halo properties.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/730
- Title:
- VIJK photometry of Whiting 1 stars
- Short Name:
- J/MNRAS/446/730
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Whiting 1 is a member of the fast-growing group of young globular clusters in the Milky Way halo. Preliminary estimates of its fundamental parameters have been provided using optical photometry and low-resolution spectroscopy. In an attempt to strengthen our knowledge of Whiting 1, in this study we employ a complementary approach. Isochrone fitting method was applied on the near-infrared colour-magnitude diagram and yields an age t=5.7+/-0.3Gyr, metallicity z=0.006+/-0.001 ([Fe/H]=-0.5+/-0.1) and distance modulus (m-M)0=17.48+/-0.10. Our results confirm that Whiting 1 is a young and moderately metal-rich globular cluster. It is one of the youngest from the Sgr dSph. We fitted an Elson, Fall and Freeman (EFF) profile to the near-infrared number counts, and measured cluster core radius r_c_=9.1+/-3.9". Two probable eclipsing variables in the cluster were found from multi-epoch V-band photometry. Finally, an unknown galaxy cluster was identified on our K versus (J-K) colour-magnitude diagram. It has a redshift z~1, and it is located at about 1arcmin from the centre of Whiting 1 at {alpha}_J2000_= 02:02:56.6, {delta}_J2000_=-03:16:09, contaminating the cluster photometry.
- ID:
- ivo://CDS.VizieR/J/A+A/443/413
- Title:
- VIKs photometry of NGC4365 globular clusters
- Short Name:
- J/A+A/443/413
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This table lists VIKs photometry for compact objects in the giant Virgo elliptical NGC 4365. The majority of these objects are globular clusters. V and I magnitudes are measured on images taken with the FORS1 instrument on the ESO Very Large Telescope, while the K magnitudes are from the SOFI imager on the ESO New Technology Telescope. No correction for foreground extinction has been applied to the photometry in the table.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/1220
- Title:
- Vi light curves of NGC6333 variables
- Short Name:
- J/MNRAS/434/1220
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report CCD V and I time series photometry of the globular cluster NGC 6333 (M9). The technique of difference image analysis has been used, which enables photometric precision better than 0.05mag for stars brighter than V~19.0mag, even in the crowded central regions of the cluster. The high photometric precision has resulted in the discovery of two new RRc stars, three eclipsing binaries, seven long-term variables and one field RRab star behind the cluster. A detailed identification chart and equatorial coordinates are given for all the variable stars in the field of our images of the cluster. Our data together with the literature V-data obtained in 1994 and 1995 allowed us to refine considerably the periods for all RR Lyrae stars. The nature of the new variables is discussed. We argue that variable V12 is a cluster member and an Anomalous Cepheid. Secular period variations, double-mode pulsations and/or the Blazhko-like modulations in some RRc variables are addressed. Through the light-curve Fourier decomposition of 12 RR Lyrae stars we have calculated a mean metallicity of [Fe/H]_ZW_=-1.70+/-0.01(statistical)+/-0.14(systematic) or [Fe/H]_UVES_=-1.67+/-0.01(statistical)+/-0.19(systematic). Absolute magnitudes, radii and masses are also estimated for the RR Lyrae stars. A detailed search for SX Phe stars in the Blue Straggler region was conducted but none were discovered. If SX Phe exist in the cluster then their amplitudes must be smaller than the detection limit of our photometry. The colour-magnitude diagram has been corrected for heavy differential reddening using the detailed extinction map of the cluster of Alonso-Garcia et al. (2012, Cat. J/AJ/143/70). This has allowed us to set the mean cluster distance from two independent estimates; from the RRab and RRc absolute magnitudes, we find 8.04+/-0.19 and 7.88+/-0.30kpc, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/578/A128
- Title:
- VI light curves of NGC4590 variables
- Short Name:
- J/A+A/578/A128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse 20 nights of CCD observations in the V and I bands of the globular cluster M68 (NGC 4590), using these to detect variable objects. We also obtained electron-multiplying CCD (EMCCD) observations for this cluster in order to explore its core with unprecedented spatial resolution from the ground. We reduced our data using difference image analysis, in order to achieve the best possible photometry in the crowded field of the cluster. In doing so, we showed that when dealing with identical networked telescopes, a reference image from any telescope may be used to reduce data from any other telescope, which facilitates the analysis significantly. We then used our light curves to estimate the properties of the RR Lyrae (RRL) stars in M68 through Fourier decomposition and empirical relations. The variable star properties then allowed us to derive the cluster's metallicity and distance. M68 had 45 previously confirmed variables, including 42 RRL and 2 SX Phoenicis (SX Phe) stars. In this paper we determine new periods, and search for new variables, especially in the core of the cluster where our method performs particularly well. We detect an additional 4 SX Phe stars, and confirm the variability of another star, bringing the total number of confirmed variable stars in this cluster to 50. We also used archival data stretching back to 1951 in order to derive period changes for some of the single-mode RRL stars, and analyse the significant number of double-mode RRL stars in M68. Furthermore, we find evidence for double-mode pulsation in one of the SX Phe stars in this cluster. Using the different classes of variables, we derived values for the metallicity of the cluster of [Fe/H]=-2.07+/-0.06 on the ZW scale, or -2.20+/-0.10 on the UVES scale, and found true distance moduli 15.00 +/- 0.11 mag (using RR0 stars), 15.00+/-0.05mag (using RR1 stars), 14.97+/-0.11mag (using SX Phe stars), and 15.00+/-0.07mag (using the M_V_-[Fe/H] relation for RRL stars), corresponding to physical distances of 10.00+/-0.49, 9.99+/-0.21, 9.84+/-0.50 and 10.00+/-0.30kpc, respectively. Thanks to the first use of difference image analysis on time-series observations of M68, we are now confident that we have a complete census of the RRL stars in this cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/398/541
- Title:
- VI light-curves of the variable stars in M13
- Short Name:
- J/A+A/398/541
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- VI light-curves of variable stars in the globular cluster M13 are presented. They are based on the CCD observations carried out at the Bialkow station of the Wroclaw University Observatory using 60-cm reflecting telescope and the CCD camera. A 6x4 arcmin-squared field of view covering the core of the cluster was observed through V and I_C filters of the Johnson-Kron-Cousins UBV(RI)_C system. About 300 frames in both filters were taken during 23 nights between 2001 February 27 and August 1. The CCD images were analyzed with the DAOPHOT profile-fitting software and Image Subtraction Method. The main result of this study is discovery of five RR Lyrae and one SX Poenicis stars. Moreover we detect non-radial pulsations in RRc star v36. We also comment the variability of all observed suspected variable stars in M13.
