- ID:
- ivo://CDS.VizieR/J/ApJS/99/551
- Title:
- BVI photometry of massive stars in M33 and M31
- Short Name:
- J/ApJS/99/551
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVI photometry of the massive stars in and around five Halpha shells in M33 and two in M31. These data can be used to statistically compare the stellar population with ionization and formation requirements of the gas shell. We have counted the numbers of massive stars encircled by the shells and embedded within the gaseous structures and corrected these numbers statistically for background and foreground interlopers. We find that the stellar production exceeds the ionization requirements of the nebulae by factors of 4-10. Thus, it is reasonable that the shells are photoionized and that a large fraction of the ionizing photons escape into the rest of the galaxy. We have also compared the number of massive stars counted and extrapolated to 7M_{sun}_ with the number required to form the shells according to a simple formation model. With one exception, we find that the number of stars estimated to be present exceeds the number required by the model for our assumptions of age and ambient gas density. This comparison and the morphology evident in Halpha images suggests that the modification of the interstellar medium by the massive stars in these regions has been far more complicated than is currently considered in formation models. There is evidence for multiple, and to some extent discreet, events in the production of the gas structures. A more detailed modeling will be necessary to adequately account for the stellar populations and Halpha morphology.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/611/323
- Title:
- BVI photometry of M5 giant branch stars
- Short Name:
- J/ApJ/611/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have tabulated lists of upper red giant, horizontal-, and asymptotic giant branch (RGB, HB, and AGB) stars in the globular cluster M5 that are complete to over 10' from the core for the RGB and AGB samples, and 8' for the HB sample. The large samples give us the most precise value of R_2_=N_AGB_/N_HB_ to date for a single globular cluster (0.176+/-0.018).
- ID:
- ivo://CDS.VizieR/J/AJ/134/2168
- Title:
- BVI photometry of M33 star clusters
- Short Name:
- J/AJ/134/2168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a survey for star clusters in M33 using HST WFPC2 archive images. We have found 104 star clusters, including 32 new ones, in the images of 24 fields that were not included in previous studies. Combining these with previous data in the literature, we increase the number of M33 star clusters found in the HST images to 242. We have derived BVI integrated photometry of these star clusters from the CCD images taken with the CFH12k mosaic camera at the CFHT.
- ID:
- ivo://CDS.VizieR/J/PASP/126/733
- Title:
- BVI photometry of M15 stars
- Short Name:
- J/PASP/126/733
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new BVI photometry containing 40,000 stars of the Galactic globular cluster M15 (NGC 7078), covering a 25'x25' area centered on the cluster with a magnitude range from the tip of the red giant branch to 3 mag below the main sequence turnoff. Using {alpha}-enhanced Dartmouth Stellar Evolution Program models, we find an age of 13.0+/-1.0Gyr and distance modulus of (m-M)_V_=15.4+/-0.1 through isochrone fitting. Unlike previous works, we find good agreement between the observed completeness-corrected stellar luminosity function and models.
- ID:
- ivo://CDS.VizieR/J/A+AS/139/491
- Title:
- BVI photometry of nearby galaxies
- Short Name:
- J/A+AS/139/491
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Integrated CCD-photometry of the dwarf nearby galaxies in B, V and I (Cousins) bands is presented. The photometry was performed in increasing circular apertures.
- ID:
- ivo://CDS.VizieR/J/MNRAS/335/291
- Title:
- BVI photometry of NGC 2547
- Short Name:
- J/MNRAS/335/291
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have developed the techniques required to use Naylor's optimal photometry algorithm of to create colour-magnitude diagrams with well-defined completeness functions. To achieve this we first demonstrate that the optimal extraction is insensitive to uncertainties in the measured position of the star. We then show how to correct the optimally extracted fluxes such that they correspond to those measured in a large aperture, so aperture photometry of standard stars can be used to place the measurements on a standard system. The technique simultaneously removes the effects of a position-dependent point spread function. Finally, we develop a method called 'ghosting', which calculates the completeness corrections in the absence of an accurate description of the point spread function. We apply these techniques to the young cluster NGC 2547 (=C0809-491), and use an X-ray-selected sample to find an age of 20-35Myr and an intrinsic distance modulus of 8.00-8.15mag. We use these isochrones to select members from our photometric surveys. Our derived luminosity function shows a well-defined Wielen dip, making NGC 2547 the youngest cluster in which such a feature has been observed. Our derived mass function spans the range 0.1-6M_{sun}_ and is similar to that for the field and the older, more massive clusters M35 and the Pleiades, supporting the idea of a universal initial mass function.
- ID:
- ivo://CDS.VizieR/J/A+AS/145/365
- Title:
- BVI photometry of NGC 7790
- Short Name:
- J/A+AS/145/365
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD photometry of the northern open star cluster NGC 7790 has been carried out in BVI photometric passbands down to V~21mag for 1150 stars of which for ~700 stars, the data is obtained for the first time. We derive the most reliable parameters for this cluster using all the available photometric, spectroscopic and proper motion data. The interstellar extinction over the cluster area is uniform and normal with E(B-V)=0.51+/-0.03mag. We determine a distance of 3.3+/-0.23Kpc to the cluster. The theoretical isochrone fittings to the Cepheid variables as well as the evolved part of the main-sequence near turn-off point indicate that the cluster is 120+/-20Myr old. We estimate the cluster radius to be 3.7' using radial stellar density profile. Both the distance and age determined using period luminosity/age relations for the Cepheid variables are consistent with their membership of the cluster. This unique opportunity has therefore been used to refine the zero-point of the period-luminosity relation for the Galactic Cepheids.
- ID:
- ivo://CDS.VizieR/J/MNRAS/377/1737
- Title:
- BVI photometry of NGC 2489
- Short Name:
- J/MNRAS/377/1737
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD BVI photometry for the southern open cluster NGC 2489 and its surrounding field. The sample consists of 2182 stars measured in an area of 13.6'x13.6', extending down to V~21.5. These data are supplemented with CORAVEL radial-velocity observations for seven red giant candidates. A cluster angular radius of 6.7+/-0.6', equivalent to 3.5+/-0.3pc, is estimated from star counts carried out inside and outside the cluster region. The comparison of the cluster colour-magnitude diagrams with isochrones of the Padova group yields E(B-V)=0.30+/-0.05, E(V-I)=0.40+/-0.05 and V-MV=12.20+/-0.25 for logt=8.70 (t=500^+130^_-100_Myr) and Z=0.019. NGC 2489 is then located at 1.8+/-0.3kpc from the Sun and 25pc below the Galactic plane. The analysis of the kinematical data allowed us to confirm cluster membership for six red giants, one of them being a spectroscopic binary. A mean radial velocity of 38.13+/-0.33km/s was derived for the cluster red giants. The properties of a sample of open clusters aligned along the line of sight of NGC 2489 are examined.
- ID:
- ivo://CDS.VizieR/J/MNRAS/367/599
- Title:
- BVI photometry of NGC 5288
- Short Name:
- J/MNRAS/367/599
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present charge-coupled device (CCD) images in the Johnson B and V and Kron-Cousins I passbands for the previously unstudied open cluster NGC 5288. The sample consists of 15688 stars reaching down to V~20.5. The cluster appears to have a relatively small but conspicuous nucleus and a low-density extended coronal region.
- ID:
- ivo://CDS.VizieR/J/A+A/381/65
- Title:
- BVI photometry of NGC 2099
- Short Name:
- J/A+A/381/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CCD observations of the rich open star cluster NGC 2099 and its surrounding field region have been carried out up to a limiting magnitude of V~22mag in B, V and I passbands for the first time. A total of ~12000 stars have been observed in the area of about 24'x24' in the cluster region, as well as ~2180 stars in the ~ 12'x12' area of the field region located ~45' away from the cluster center. The cluster parameters determined by fitting the convective core overshoot isochrones in the V, (B-V) and V, (V-I) diagrams are E(B-V)=0.30+/-0.40mag, distance=1360+/-100pc, age=400Myr and metallicity Z=0.008.
