- ID:
- ivo://CDS.VizieR/J/ApJS/69/99
- Title:
- NGC 6334 centers of star formation JHK photometry
- Short Name:
- J/ApJS/69/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared observations of specific sites of high-mass star formation activity in the giant H II region/molecular cloud complex NGC 6334. The observations consist of high-spatial resolution broad-band imaging, chopping photometry, and moderate-resolution spectra. The imaging observations provide full spatial sampling of the stellar population over a significant area of the cloud to a limit of K=13.5mag and reveal many faint red sources around the sites of recent high-mass star formation. We show that most of these sources are associated with the NGC 6334 molecular cloud and are not Galactic field sources. In the majority of the regions the embedded sources are primarily reddened main-sequence stars of low and intermediate mass though in three of the 11 regions studied there is a high proportion of objects showing H-K excesses which are therefore probably pre main-sequence. We identify the red objects in FIR-I as belonging to a very young compact cluster of ~1pc spatial extent. In FIR-V an unexpectedly large number of bright red sources are detected which have CO absorption at 2.3{mu}m. The probability that these objects are Galactic field sources is very low and if they are giant stars associated with NGC 6334 their implied ages (>10^9^yr) are inconsistent with the many indicators of extreme youth in this region. We propose that they form a hitherto unrecognized population of high-luminosity pre-main-sequence objects. Two objects with similar characteristics are also found in images of an area of the NGC 6334 molecular cloud to the north of FIR-V (SH-1). In FIR-V we also find evidence that the molecular outflow from the already known high-mass protostar has triggered intermediate-mass star formation via interaction with the local interstellar medium. Mass functions have been derived for the embedded stellar aggregates under the assumption that all sources lie on the main sequence unless otherwise indicated. The effect of a population of pre-main-sequence objects on the derived mass function slopes is shown to be small. Embedded aggregates in NGC 6334 have stellar mass distributions similar to those found both in young visible clusters and in other embedded clusters. This suggests that the slope of the mass function is relatively insensitive to conditions in the star formation environment and that the solar neighborhood value applies to star formation regions on scales as small as 1pc and of ages less than 10^7^yr.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/421/2998
- Title:
- NGC 6822 Cepheids JHKs light curves
- Short Name:
- J/MNRAS/421/2998
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent estimates of the Cepheid distance modulus of NGC 6822 differ by 0.18mag. To investigate this we present new multi-epoch JHKs photometry of classical Cepheids in the central region of NGC 6822 and show that there is a zero-point difference from earlier work. These data together with optical and mid-infrared observations from the literature are used to derive estimates of the distance modulus of NGC 6822. A best value of 23.40mag is adopted, based on a Large Magellanic Cloud (LMC) distance modulus of 18.50mag. The standard error of this quantity is ~0.05mag. We show that to derive consistent moduli from Cepheid observations at different wavelengths, it is necessary that the fiducial LMC period-luminosity relations at these wavelengths should refer to the same subsample of stars. Such a set is provided. A distance modulus based on RR Lyrae variables agrees with the Cepheid result.
- ID:
- ivo://CDS.VizieR/J/A+AS/134/525
- Title:
- NGC 6611 compiled catalog
- Short Name:
- J/A+AS/134/525
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains data on stars in sky area of the open cluster NGC 6611. The catalogue is based on a new reduction of positions, proper motions, and photometric data whenever published in this region and includes among others, Hipparcos, AC/GSC and Tautenburg Schmidt plate observations. The basis of compiled catalogue is made of stars distributed over a circular area with radius of 22.8arcmin centered on the cluster NGC 6611 (Kharchenko and Schilbach, 1995AN....316...91K). To construct the compiled catalogue, we used also astrometric data published by Van Schewick (1962VeUSB..62....1V), Kamp (1974A&AS...16....1K), Tucholke et al. (1986A&AS...66..311T), Bastian and Roeser (1993, Cat. <I/193>), Roeser (1996, in "An updated GSC as the astrometric reference for minor planet observations", Kluwer Dordrecht, p. 481.), Hillenbrand et al. (1993, Cat. <J/AJ/106/1906>), and photometry published by Walker (1961ApJ...133..438W), Hoag et al. (1961PUSNO..17..343H), Hiltner and Morgan (1969AJ.....74.1152H), Sagar and Joshi (1979Ap&SS..66....3S), The et al (1990A&AS...82..319T), Hillenbrand et al. (1993, Cat. <J/AJ/106/1906>) as it described by Belikov et al. (1998, A&A, in press, this paper, 1999A&AS..134..525B). The catalogue contains 2185 stars up to the limiting magnitudes V=16.78mag. It includes equatorial (equinox 2000.0 and epoch 1990.77) and rectangular coordinates, absolute proper motions with respect to the Hipparcos proper motion system, photometric data (results of UBV, HJK photometry and color excess) and cluster membership probabilities. X - and Y - directions correspond to right ascension and declination directions. The rms errors of right ascension and declination are 0.008sec and 0.14arcsec, respectively. The individual rms errors of proper motions and V-magnitudes are given in the catalogue. The membership probabilities of the cluster stars belonging to the core and corona were determined using information both on spatial and proper motion distributions of stars in the field.
- ID:
- ivo://CDS.VizieR/J/A+A/601/A56
- Title:
- NGC 6802 dwarf cluster members and non-members
- Short Name:
- J/A+A/601/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Milky Way open clusters are very diverse in terms of age, chemical composition, and kinematic properties. Intermediate-age and old open clusters are less common, and it is even harder to find them inside the solar Galactocentric radius, due to the high mortality rate and strong extinction inside this region. NGC 6802 is one of the inner disk open clusters (IOCs) observed by the $Gaia$-ESO survey (GES). This cluster is an important target for calibrating the abundances derived in the survey due to the kinematic and chemical homogeneity of the cluster members in open clusters. Using the measurements from $Gaia$-ESO internal data release 4 (iDR4), we identify 95 dwarf main-sequence stars as cluster members from the GIRAFFE target list, and 8 red giants as cluster members from the UVES target list. The dwarf cluster members have a median radial velocity of 13.6+/-1.9km/s, while the giant cluster members have a median radial velocity of 12.0+/-0.9km/s and a median [Fe/H] of 0.10+/-0.02dex. The color-magnitude diagram of these cluster members suggests an age of $0.9+/-0.1Gyr, with (m-M)_0_=11.4 and E(B-V)=0.86. We perform the first chemical abundance analysis of NGC 6802, including 27 element species. To gain a more general picture about IOCs, the measurements of NGC6802 are compared with those of other IOCs previously studied by GES, i.e., NGC 4815, Trumpler 20, NGC 6705, and Berkeley 81. NGC 6802 shows similar C, N, Na, and Al abundances as other IOCs. The abundance versus cluster turn-off mass for these elements in the five GES IOCs cannot firmly exclude any one of the competing nucleosynthetic models, including: standard models; models with rotation induced mixing and/or thermohaline mixing. The five GES IOCs, particularly NGC 6802, seem to have higher s-process element abundances than that of the inner disk field stars.
- ID:
- ivo://CDS.VizieR/J/A+A/654/A40
- Title:
- NGC1042 g and r deep final images
- Short Name:
- J/A+A/654/A40
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the first results of the LBT Imaging of Galaxy Haloes and Tidal Structures (LIGHTS) survey. LIGHTS is an ongoing observational campaign with the 2x8.4m Large Binocular Telescope (LBT) aiming to explore the stellar haloes and the low surface brightness population of satellites down to a depth of mu_V_~31mag/arcsec^2^ (3s in 10"x10" boxes) of nearby galaxies. We simultaneously collected deep imaging in the g and r Sloan filters using the Large Binocular Cameras (LBCs). The resulting images are 60 times (i.e. 4.5mag) deeper than those from the Sloan Digital Sky Survey (SDSS), and they have characteristics comparable (in depth and spatial resolution) to the ones expected from the future Legacy Survey of Space and Time (LSST). Here we show the first results of our pilot programme targeting NGC1042 (an M33 analogue at a distance of 13.5Mpc) and its surroundings. The depth of the images allowed us to detect an asymmetric stellar halo in the outskirts of this galaxy whose mass (1.4+/-0.4x10^8^M_{sun}_) is in agreement with the Lambda Cold Dark Matter (LambdaCDM) expectations. Additionally, we show that deep imaging from the LBT reveals low mass satellites (a few times 10^5^M_{sun}_) with very faint central surface brightness mu_V(0)_~27mag/arcsec^2^(i.e. similar to Local Group dwarf spheroidals, such as Andromeda XIV or Sextans, but at distances well beyond the local volume). The depth and spatial resolution provided by the LIGHTS survey open up a unique opportunity to explore the `missing satellites' problem in a large variety of galaxies beyond our Local Group down to masses where the difference between the theory and observation (if any) should be significant.
- ID:
- ivo://CDS.VizieR/J/AJ/140/2101
- Title:
- NGC 5128 globular clusters photometry
- Short Name:
- J/AJ/140/2101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometry for 323 of the globular clusters in NGC 5128 (Centaurus A), measured for the first time in the g'r'i'z' filter system. The color indices are calibrated directly to standard stars in the g'r'i'z' system and are used to establish the fiducial mean colors for the blue and red (low and high metallicity) globular cluster sequences. We also use previously published spectroscopically measured abundances to establish the conversion between the most metallicity-sensitive colors ((g'-r')_0_,(g'-i')_0_) and metallicity, [Fe/H].
- ID:
- ivo://CDS.VizieR/J/AJ/134/494
- Title:
- NGC 5128 globular clusters UBVRICMT1 phot. & RV
- Short Name:
- J/AJ/134/494
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new kinematic and dynamic study of the halo of the giant elliptical galaxy NGC 5128 is presented. From a spectroscopically confirmed sample of 340 globular clusters and 780 planetary nebulae, the rotation amplitude, rotation axis, velocity dispersion, and total dynamical mass are determined for the halo of NGC 5128.
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/3218
- Title:
- NGC 7538 IRS 1-3 and IRS 9 sources
- Short Name:
- J/MNRAS/443/3218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep and high-resolution (FWHM~0.4-arcsec) near-infrared (NIR) imaging observations of the NGC 7538 IRS 1-3 region (in JHK bands), and IRS 9 region (in HK bands) using the 8.2m Subaru telescope. The NIR analysis is complemented with Giant Metrewave Radio Telescope (GMRT) low-frequency observations at 325, 610, and 1280MHz, molecular line observations of H^13^CO^+^ (J=1-0), and archival Chandra X-ray observations. Using the 'J-H/H-K' diagram, 144 Class II and 24 Class I young stellar object (YSO) candidates are identified in the IRS 1-3 region. Further analysis using 'K/H-K' diagram yields 145 and 96 red sources in the IRS 1-3 and IRS 9 regions, respectively. A total of 27 sources are found to have X-ray counterparts. The YSO mass function (MF), constructed using a theoretical mass-luminosity relation, shows peaks at substellar (~0.08-0.18M_{sun}_) and intermediate (~1-1.78M_{sun}_) mass ranges for the IRS 1-3 region. The MF can be fitted by a power law in the low-mass regime with a slope of {Gamma} ~0.54-0.75, which is much shallower than the Salpeter value of 1.35. An upper limit of 10.2 is obtained for the star to brown dwarf ratio in the IRS 1-3 region. GMRT maps show a compact HII region associated with the IRS 1-3 sources, whose spectral index of 0.87+/-0.11 suggests optical thickness. This compact region is resolved into three separate peaks in higher resolution 1280MHz map, and the 'east' subpeak coincides with the IRS 2 source. H^13^CO^+^ (J=1-0) emission reveals peaks in both IRS 1-3 and IRS 9 regions, none of which are coincident with visible nebular emission, suggesting the presence of dense cloud nearby. The virial masses are approximately of the order of 1000 and 500M_{sun}_ for the clumps in IRS 1-3 and IRS 9 regions, respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/127/1131
- Title:
- NGC 1333 low-mass stars infrared photometry
- Short Name:
- J/AJ/127/1131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of near-infrared imaging and low-resolution near-infrared spectroscopy of low-mass objects in the NGC 1333 molecular cloud. A JHK survey of an 11.4'x11.7' area of the northern cluster was conducted to a sensitivity of K<=16mag. Using near-infrared magnitudes and colors from this and previously published surveys, 25 brown dwarf candidates were selected toward the high-extinction cloud core. Spectra in the K band were obtained and comparisons of the depths of water vapor absorption bands in our candidate objects with a grid of dwarf, subgiant, and giant standards were made to derive spectral types. These data were then used to derive effective temperatures and stellar luminosities that, when combined with theoretical tracks and isochrones for pre-main-sequence objects, resulted in estimates for their masses and ages.
- ID:
- ivo://CDS.VizieR/J/A+A/623/A159
- Title:
- NGC6530 member parameters from Gaia-ESO survey
- Short Name:
- J/A+A/623/A159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In very young clusters, stellar age distribution is the empirical proof of the duration of star formation (SF) and of the physical mechanisms involved in the process. We derived accurate stellar ages for the cluster NGC6530, associated with the Lagoon Nebula to infer its SF history. We use the Gaia-ESO survey observations and Gaia DR2 data, to derive cluster membership and fundamental stellar parameters. We identified 652 confirmed and 9 probable members. The reddening inferred for members and non-members allows us to distinguish MS stars and giants, in agreement with the distances inferred from Gaia DR2 data. The foreground and background stars show a spatial pattern that traces the 3D structure of the nebular dust component. We derive stellar ages for 382 confirmed cluster members and we find that the gravity-sensitive gamma index distribution for M stars is correlated with stellar age. For all members with Teff<5500K, the mean logarithmic age is 5.84 (units of years) with a dispersion of 0.36dex. The age distribution of stars with accretion and/or disk (CTTSe) is similar to that of stars without accretion and without disk (WTTSp). We interpret this dispersion as evidence of a real age spread since the total uncertainties on age determinations, derived from Monte Carlo simulations, are significantly smaller than the observed spread. This conclusion is supported by the evidence of a decreasing of the gravity-sensitive gamma index as a function of stellar ages. The presence of the age spread is also supported by the spatial distribution and the kinematics of old and young members. In particular, members with accretion and/or disk, formed in the last 1Myr, show evidence of subclustering around the cluster center, in the Hourglass Nebula and in the M8-E region, suggesting a possible triggering of star formation events by the O-type star ionization fronts.
