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- ID:
- ivo://CDS.VizieR/J/MNRAS/404/1475
- Title:
- JHK photometry of Leo I AGB and red giants
- Short Name:
- J/MNRAS/404/1475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A near-infrared imaging study of the evolved stellar populations in the dwarf spheroidal galaxy Leo I is presented. Based on JHK observations obtained with the WFCAM wide-field array at the United Kingdom Infrared Telescope, we build a near-infrared photometric catalogue of red giant branch (RGB) and asymptotic giant branch (AGB) stars in Leo I over a 13.5arcmin^2^ area. The V-K colours of RGB stars, obtained by combining the new data with existing optical observations, allow us to derive a distribution of global metallicity [M/H] with average [M/H]=-1.51 (uncorrected) or [M/H]=-1.24+/-.05(int)+/-0.15(syst) after correction for the mean age of Leo I stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/118/177
- Title:
- JHK photometry of M31 spiral arm
- Short Name:
- J/ApJS/118/177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep high-resolution JHK images of a 2'x2' field around the OB association A24 near the 7kpc spiral arm in M31 were measured to yield photometric data of more than 3000 stars with the faintest magnitude being J=21.3, H=20.5, and K=19.6. The photometric data for the 1037 stars that are brightest in the K band are presented. Judging from the color-magnitude and the two-color diagrams, we find that the majority of the observed stars are AGB stars including large-amplitude variables. They are distributed smoothly over the observed field, and we find no clear evidence of varying extinction over the field for these red stars. The present sample includes bright AGB stars of M_K_<=-8 and about 30 young blue objects of (J-H)<0.75 that are brighter than M_J_~=-6.5.
- ID:
- ivo://CDS.VizieR/J/A+A/564/L3
- Title:
- JHK photometry of NGC 3115 globular clusters
- Short Name:
- J/A+A/564/L3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combined new near-infrared VLT/HAWK-I data of the globular clusters (GCs) in the isolated edge-on S0 galaxy NGC 3115 with optical and spectroscopic ones taken from the literature, with the aim of analyzing the multiband GC color distributions. A recent study from the SLUGGS survey has shown that the GCs in this galaxy follow a bimodal distribution of CaII triplet indices. Thus, NGC3115 presents a critical example of a GC system with multiple, distinct, metallicity subpopulations, and this may argue against the "projection" scenario, which posits that the ubiquitous color bimodality mainly results from nonlinearities in the color- metallicity relations. Using optical, NIR, and spectroscopic data, we found strong and consistent evidence of index bimodality, which independently confirms the metallicity bimodality in NGC 3115 GCs. At the same time, we also found evidence for some color-color nonlinearity. Taken in the broader context of previous studies, the multicolor consistency of the GC bimodality in NGC 3115 suggests that in cases where GC systems exhibit clear differences between their optical and optical-NIR color distributions (as in some giant ellipticals), the apparent inconsistencies most likely result from nonlinearities in the color-metallicity relations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/385/1045
- Title:
- JHKsIc photometry of AGB in Phoenix dwarf gal.
- Short Name:
- J/MNRAS/385/1045
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- JHKs near-infrared photometry of stars in the Phoenix dwarf galaxy is presented and discussed. Combining these data with the optical photometry of Massey et al. (2007, Cat. <J/AJ/133/2393>) allows a rather clean separation of field stars from Phoenix members. The discovery of a Mira variable (P=425d), which is almost certainly a carbon star, leads to an estimate of the distance modulus of 23.10+/-0.18 that is consistent with other estimates and indicates the existence of a significant population of age ~2Gyr. The two carbon stars of Da Costa have Mbol=-3.8 and are consistent with belonging to a population of similar age; some other possible members of such a population are identified. A Da Costa non-carbon star is {Delta}Ks~0.3mag brighter than these two carbon stars. It may be an asymptotic giant branch star of the dominant old population. The nature of other stars lying close to it in the Ks, (J-Ks) diagram needs studying.
- ID:
- ivo://CDS.VizieR/J/A+A/406/75
- Title:
- JHKs magnitudes of variables in NGC 5128
- Short Name:
- J/A+A/406/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first variable star catalogue in a giant elliptical galaxy NGC 5128 (Centaurus A) is presented. Using multi-epoch observations with ISAAC at the VLT we have detected 1504 red variables in two halo fields covering 10.46-arcmin square. For the variables with at least 10 good measurements, periods and amplitudes were determined using Fourier analysis and non-linear sine-curve fitting algorithms. The final catalogue contains 1146 long period variables with well established light curve parameters. Periods, amplitudes, JsHKs photometry as well as individual KS-band magnitudes are provided for all the variables. The distribution of amplitudes ranges from 0.3 to a few magnitudes in the Ks-band, with a median value around 0.7mag. The amplitudes, mean magnitudes and periods indicate that the majority of variables belong to the class of long period variables with semiregular and Mira variables. Exhaustive simulations were performed in order to assess the completeness of our catalogue and the accuracy of the derived periods.
- ID:
- ivo://CDS.VizieR/J/A+A/511/A50
- Title:
- JHks of GOODS-South field
- Short Name:
- J/A+A/511/A50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the final public data release of the VLT/ISAAC near-infrared imaging survey in the GOODS-South field. The survey covers an area of 172.5, 159.6 and 173.1arcmin^2^ in the J, H, and Ks bands, respectively. For point sources total limiting magnitudes of J=25.0, H=24.5, and Ks=24.4 (5{sigma}, AB) are reached within 75% of the survey area. Thus these observations are significantly deeper than the previous EIS Deep Public Survey which covers the same region. The image quality is characterized by a point spread function ranging between 0.34" and 0.65" FWHM. The images are registered to a common astrometric grid defined by the GSC 2 with an accuracy of ~0.06" RMS over the whole field. The overall photometric accuracy, including all systematic effects, adds up to 0.05mag. The data are publicly available from the ESO science archive facility.
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/2216
- Title:
- JHKs photometry of AGB stars in NGC 6822
- Short Name:
- J/MNRAS/428/2216
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- JHKs photometry is presented from a 3.5yr survey of the central regions of the irregular galaxy NGC 6822. The morphology of the colour-magnitude and colour-colour diagrams is discussed with particular reference to M-, S- and C-type asymptotic giant branch (AGB) stars and to M supergiants. Mean JHKs magnitudes and periods are given for 11 O-rich and 50 presumed C-rich Miras. Data are also listed for 27 large-amplitude AGB stars without periods and for 69 small-amplitude AGB variables. The slope of the bolometric period-luminosity relation for the C-rich Miras is in good agreement with that in the Large Magellanic Cloud. Distance moduli derived from the C- and O-rich Miras are in agreement with other estimates. The period distribution of C-rich Miras in NGC 6822 is similar to that in the Magellanic Clouds, but differs from that in the dwarf spheroidals in the Local Group. In the latter there is a significant proportion of large-amplitude, short-period variables indicating a population producing old carbon-rich AGB stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/388/1185
- Title:
- JHKs photometry of LeoII dSph giants
- Short Name:
- J/MNRAS/388/1185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the evolved stellar populations in the dwarf spheroidal galaxy Leo II, based on JHKs observations obtained with the near-infrared array WFCAM at the UKIRT telescope. Combining the new data with optical data, we derived photometric estimates of the distribution of global metallicity [M/H] of individual red giant stars from their V-Ks colours. Our results are consistent with the metallicities of red giant branch (RGB) stars obtained from CaII triplet spectroscopy, once the age effects are considered.
- ID:
- ivo://CDS.VizieR/J/A+A/487/131
- Title:
- JHKs photometry of LPVs in M33
- Short Name:
- J/A+A/487/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Wide-field JHKs near-infrared observations covering an area of 1.8x1.8deg^2^ centred on M33 were obtained using WFCAM at UKIRT. These data show a large population of intermediate-age asymptotic giant branch stars (AGB). We have used both C-type and M-type AGB stars to determine spatial variations in metallicity and mean age across the galaxy. We distinguished between C-type and M-type AGB stars from their location in the colour-magnitude diagram (J-Ks, Ks). The distribution of these stars is supported by a cross-identification between our sample and a catalogue of optically confirmed, long-period variable stars, as well as with the list of sources detected by Spitzer in the mid-infrared. We calculated the C/M ratio and the orientation of the galaxy in the sky, and compared the Ks magnitude distribution with theoretical distributions spanning a range of metallicities and star formation rates (SFRs). The C/M ratio surface map confirms a metallicity gradient in the galaxy corresponding to a spread in [Fe/H]=0.6dex with substructures in the inner and outer galaxy. Magnitude and colour variations suggest orientation and extinction effects on the galaxy disc. Maps showing the distribution of mean age and metallicity obtained from the Ks method suggest that: the outer galaxy disc/halo is metal poorer than the nuclear region and metal-rich clumps in the inner galaxy change location with time. The average outer ring and nuclear stellar population is ~6Gyr old while central regions are a few Gyr younger.
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