- ID:
- ivo://CDS.VizieR/J/AJ/143/16
- Title:
- HST photometry of IC 883 star clusters
- Short Name:
- J/AJ/143/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New optical Hubble Space Telescope (HST), Spitzer Space Telescope, Galaxy Evolution Explorer, and Chandra observations of the single-nucleus, Luminous InfraRed Galaxy (LIRG) merger IC 883 are presented. The galaxy is a member of the Great Observatories All-sky LIRG Survey (GOALS) and is of particular interest for a detailed examination of a luminous late-stage merger due to the richness of the optically visible star clusters and the extended nature of the nuclear X-ray, mid-IR, CO, and radio emission. In the HST Advanced Camera for Surveys images, the galaxy is shown to contain 156 optically visible star clusters distributed throughout the nuclear regions and tidal tails of the merger, with a majority of visible clusters residing in an arc ~3-7kpc from the position of the mid-infrared core of the galaxy. The luminosity functions of the clusters have an {alpha}_F435W_~-2.17 +/-0.22 and {alpha}_F814W_~-2.01+/-0.21, compared with V-band-derived values measured for the well-studied LIRG NGC 34 and the Antennae Galaxy of {alpha}~-1.7+/-0.1 and -2.13+/-0.07, respectively.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/397/473
- Title:
- HST photometry of M51 cluster
- Short Name:
- J/A+A/397/473
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an analysis of the HST-WFPC2 observations of the interacting galaxy M 51. From the observations in 5 broadband filters (UBVRI) and two narrowband filters (H{alpha} and [OIII]) we study the cluster population in a region of 3.2x3.2kpc^2^ in the inner spiral arms of M 51, at a distance of about 1 to 3kpc from the nucleus. We found 877 cluster candidates and we derived their ages, initial masses and extinctions by means of a comparison between the observed spectral energy distribution and the predictions from cluster synthesis models for instantaneous star formation and solar metallicity.
- ID:
- ivo://CDS.VizieR/J/ApJ/703/42
- Title:
- HST photometry of M87 globular clusters
- Short Name:
- J/ApJ/703/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the M87 GC system using deep, archival HST/ACS imaging with the F606W and F814W filters, in which we find a significant color-magnitude relation for the metal-poor globular clusters (GCs). The slope of this relation in the I versus V-I color-magnitude diagram ({gamma}_I_=-0.024+/-0.006) is perfectly consistent with expectations based on previously published results using data from the ACS Virgo Cluster Survey. We show that previously measured half-light radii of M87 GCs from best-fit PSF-convolved King models are consistent with the more accurate measurements in this study, and we also explain how the color-magnitude relation for metal-poor GCs is real and cannot be an artifact of the photometry. We fit Gaussian and evolved Schechter functions to the luminosity distribution of GCs across all colors, as well as divided into blue and red subpopulations, finding that the blue GCs have a brighter mean luminosity and a narrower distribution than the red GCs. Finally, we present a catalog of astrometry and photometry for 2250 M87 GCs.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A155
- Title:
- HST photometry of M31 globular clusters
- Short Name:
- J/A+A/544/A155
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have derived a new calibration of the MV(HB)-[Fe/H] relation by exploiting the large photometric database of old GCs in M31 in the HST archive. We collected BVI data for 48 old GCs in M31 and analysed them by applying the same methods and procedures to all objects. We obtained a set of homogeneous colour-magnitude diagrams (CMDs) that were best-fitted with the fiducial CMD ridge lines of selected Milky Way template GCs. Reddening, metallicity, horizontal branch (HB) luminosity and distance were determined self-consistently for each cluster. There are three main results of this study: i) the relation MV(HB)=0.25(+/-0.02)[Fe/H]+0.89(+/-0.03), which is obtained from the above parameters and is calibrated on the distances of the template Galactic GCs; ii) the distance modulus to M31 of (m-M)_0_=24.42+/-0.06mag, that is the first determination of the distance to M31 based on the characteristics of its GC system, and is calibrated on Galactic GCs, iii) the distance to the Large Magellanic Cloud (LMC), which is estimated to be 18.54+/-0.07mag as a consequence of the previous results.
- ID:
- ivo://CDS.VizieR/J/ApJ/667/L145
- Title:
- HST Photometry of M82 region B
- Short Name:
- J/ApJ/667/L145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope of the "fossil" starburst region B in the nearby starburst galaxy M82. By comparing UBVI photometry with models, we derive ages and extinctions for 35 U-band-selected star clusters. We find that the peak epoch of cluster formation occurred ~150Myr ago, in contrast to earlier work that found a peak formation age of 1.1Gyr. The difference is most likely due to our inclusion of U-band data, which are essential for accurate age determinations of young cluster populations. We further show that the previously reported turnover in the cluster luminosity function is probably due to the neglect of the effect of extended sources on the detection limit. The much younger cluster ages we derive clarifies the evolution of the M82 starburst. The M82-B age distribution now overlaps with the ages of the nuclear starburst, the clusters formed on the opposite side of the disk, and the last encounter with M81, some 220Myr ago.
- ID:
- ivo://CDS.VizieR/J/AcA/59/47
- Title:
- HST photometry of M33 stellar clusters
- Short Name:
- J/AcA/59/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used deep ACS/WFC images of M33 to check the nature of extended objects detected by the ground based survey of Zloczewski et al. (2008, Cat. J/AcA/58/23). A total of 24 candidates turned out to be genuine compact stellar clusters. In addition we detected 91 new clusters. Equatorial coordinates, integrated magnitudes and angular sizes are listed for all 115 objects. Forty-two clusters have sufficiently red colors to be candidates for old globulars. For four clusters we extracted resolved stellar photometry. Object 33-3-018 located in the outer disk of M33 turned out to be a young cluster with an age estimated at 200-350Myr. Cluster ZK-90 has an age of 3-5Gyr. The remaining two clusters have intermediate ages ranging from one to a few Gyr.
- ID:
- ivo://CDS.VizieR/J/AJ/142/129
- Title:
- HST photometry of NGC 4449 clusters
- Short Name:
- J/AJ/142/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the star cluster population in the starburst irregular galaxy NGC 4449 based on B, V, I, and H{alpha} images taken with the Advanced Camera for Surveys on the Hubble Space Telescope. We derive cluster properties such as size, ellipticity, and total magnitude. Cluster ages and masses are derived fitting the observed spectral energy distributions with different population synthesis models.
- ID:
- ivo://CDS.VizieR/J/ApJ/668/209
- Title:
- HST photometry of NGC 5866 globulars
- Short Name:
- J/ApJ/668/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a detailed study of the globular cluster (GC) system in the galaxy NGC 5866 based on F435W, F555W, and F625W (~B, V, and R) Hubble Space Telescope Advanced Camera for Surveys images. Adopting color, size, and shape selection criteria, the final list of GC candidates comprises 109 objects, with small estimated contamination from background galaxies, and foreground stars.
- ID:
- ivo://CDS.VizieR/J/A+A/550/A7
- Title:
- HST photometry of Sculptor group dwarf galaxies
- Short Name:
- J/A+A/550/A7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We focus on the resolved stellar populations of one early-type and four transition-type dwarf galaxies in the Sculptor group, with the aim to examine the potential presence of population gradients and place constraints on their mean metallicities. We use deep Hubble Space Telescope images to construct color-magnitude diagrams, from which we select stellar populations that trace different evolutionary phases in order to constrain their range of ages and metallicities, as well as to examine their spatial distribution. In addition, we use the resolved stars in the red giant branch in order to derive photometric metallicities.
- ID:
- ivo://CDS.VizieR/J/ApJ/766/20
- Title:
- HST photometry of star clusters in M82
- Short Name:
- J/ApJ/766/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric study of star clusters in the nearby starburst galaxy M82 based on the UBVI-, YJ- and H-band Hubble Space Telescope images. We find 1105 star clusters with V<23mag. Of those, 1070 are located in the disk region, while 35 star clusters are in the halo region. The star clusters in the disk are composed of a dominant blue population with a color peak at (B-V)_0_~0.45, and a weaker red population. The luminosity function of the disk clusters shows a power-law distribution with a power-law index {alpha}=-2.04+/-0.03, and the scale height of their distribution is h_z_=9.64"+/-0.40" (164+/-7pc), similar to that of the stellar thin disk of M82. We have derived the ages of ~630 star clusters using the spectral energy distribution fit method by comparing UBVI(YJ)H-band photometric data with the simple stellar population models. The age distribution of the disk clusters shows that the most dominant cluster population has ages ranging from 100Myr to 1Gyr, with a peak at about 500Myr. This suggests that M82 has undergone a disk-wide star formation about 500Myr ago, probably through the interaction with M81. The brightest star clusters in the nuclear region are much brighter than those in other regions, indicating that more massive star clusters are formed in the denser environments. On the other hand, the colors of the halo clusters are similar to those of globular clusters in the Milky Way, and their ages are estimated to be older than 1Gyr. These are probably genuine old globular clusters in M82.
