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- ID:
- ivo://CDS.VizieR/J/A+A/592/A20
- Title:
- NGC 1316 and NGC 612 WISE images
- Short Name:
- J/A+A/592/A20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Most radio galaxies are hosted by giant gas-poor ellipticals, but some contain significant amounts of dust, which is likely to be of external origin. In order to characterize the mid-IR properties of two of the most nearby and brightest merger-remnant radio galaxies of the Southern hemisphere, NGC 1316 (Fornax A) and NGC 612 (PKS 0131-36), we used observations with the Wide-field Infrared Survey Explorer (WISE) at wavelengths of 3.4, 4.6, 12 and 22 micron and Spitzer mid-infrared spectra. By applying a resolution-enhancement technique, new WISE images were produced at angular resolutions ranging from 2.6" to 5.5". Global measurements were performed in the four WISE bands, and stellar masses and star-formation rates were estimated using published scaling relations. Two methods were used to uncover the distribution of dust, one relying on two-dimensional fits to the 3.4 micron images to model the starlight, and the other one using a simple scaling and subtraction of the 3.4 micron images to estimate the stellar continuum contribution to the emission in the 12 and 22 micron bands. The two galaxies differ markedly in their mid-IR properties. The 3.4 micron brightness distribution can be well represented by the superposition of two Sersic models in NGC 1316 and by a Sersic model and an exponential disk in NGC 612. The WISE colors of NGC 1316 are typical of those of early-type galaxies; those of NGC 612 are in the range found for star-forming galaxies. From the 22 micron luminosity, we infer a star-formation rate of about 0.7 solar masses per year in NGC 1316 and about 7 solar masses per year in NGC 612. Spitzer spectroscopy shows that the 7.7-to-11.3 micron PAH line ratio is significantly lower in NGC 1316 than in NGC 612. The WISE images reveal resolved emission from dust in the central 1'-2' of the galaxies. In NGC 1316, the extra-nuclear emission coincides with two dusty regions NW and SE of the nucleus seen in extinction in optical images and where molecular gas is known to reside. In NGC 612 it comes from a warped disk. This suggests a recent infall onto NGC 1316 and disruption of one or several smaller gas-rich galaxies, but a smoother accretion in NGC 612. While the nucleus of NGC 1316 is currently dormant and the galaxy is likely to evolve into a passive elliptical, NGC 612 has the potential of growing a larger disk and sustaining an active nucleus. NGC 1316 and NGC 612 represent interesting challenges to models of formation and evolution of galaxies and AGNs.
- ID:
- ivo://CDS.VizieR/J/ApJ/671/605
- Title:
- NGC 2264 and ONC PMS stars in the infrared
- Short Name:
- J/ApJ/671/605
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of pre-main-sequence star rotation periods reveal slow rotators in young clusters of various ages, indicating that angular momentum is somehow removed from these rotating masses. The mechanism by which spin-up is regulated as young stars contract has been one of the longest standing problems in star formation. Attempts to observationally confirm the prevailing theory that magnetic interaction between the star and its circumstellar disk regulates these rotation periods have produced mixed results. In this paper, we use the unprecedented disk identification capability of the Spitzer Space Telescope to test the star-disk interaction paradigm in two young clusters, NGC 2264 and the Orion Nebula Cluster (ONC).
- ID:
- ivo://CDS.VizieR/J/A+AS/127/471
- Title:
- NGC 6380 and Terzan 12 VI photometry
- Short Name:
- J/A+AS/127/471
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present V, I photometry of the bulge globular clusters NGC 6380 and Terzan 12, using the ESO NTT telescope. For the first time colour-magnitude diagrams are obtained for these clusters, allowing us to derive reliable cluster parameters. From the colour-magnitude diagram morphology both clusters result to be metal-rich. For NGC 6380 we estimate [Fe/H]~-0.5, a reddening of E(B-V)=1.07 and a distance of d~9.8 kpc. For Terzan 12 we obtain [Fe/H]~-0.5, E(B-V)=2.06 and d~3.4kpc.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/106
- Title:
- NGC5617 and Trumpler 22 stars BV mag and RV
- Short Name:
- J/MNRAS/453/106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using photometry and high-resolution spectroscopy we investigate for the first time the physical connection between the open clusters NGC 5617 and Trumpler 22. Based on new CCD photometry we report their spatial proximity and common age of ~70Myr. Based on high-resolution spectra collected using the HERMES and UCLES spectrographs on the Anglo-Australian telescope, we present radial velocities and abundances for Fe, Na, Mg, Al, Si, Ca, and Ni. The measured radial velocities are -38.63+/-2.25km/s for NGC 5617 and -38.46+/-2.08km/s for Trumpler 22. The mean metallicity of NGC 5617 was found to be [Fe/H]=-0.18+/-0.02 and for Trumpler 22 was found to be [Fe/H]=-0.17+/-0.04. The two clusters share similar abundances across the other elements, indicative of a common chemical enrichment history of these clusters. Together with common motions and ages we confirm that NGC 5617 and Trumpler 22 are a primordial binary cluster pair in the Milky Way.
- ID:
- ivo://CDS.VizieR/J/A+A/554/A128
- Title:
- NGC 6824 and UGC 11919 data cubes
- Short Name:
- J/A+A/554/A128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss the results of a mass decomposition of two spiral galaxies, NGC 6824 and UGC 11919. In a previous analysis of the Hyperleda catalog, the galaxies were identified as having a peculiar dynamical mass-to-light ratio. The aim of this study is to confirm or disprove the preliminary findings, indicating a non-standard stellar initial mass function (IMF) for the galaxies. The surface photometry in B,V, and R bands was carried out with the Apache Point 0.5-m telescope and the HI data cubes were obtained with the Westerbork Synthesis Radio Telescope (WSRT). Photometric profiles were decomposed into bulge and exponential disk components.
- ID:
- ivo://CDS.VizieR/J/MNRAS/356/647
- Title:
- NGC 6404 and 6583 VI photometry
- Short Name:
- J/MNRAS/356/647
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on VI charge-coupled device photometry of two fields centred in the region of the open clusters NGC 6404 and 6583 down to V=22.0. So far these clusters have never been studied, and we provide for the first time estimates of their fundamental parameters, namely, radial extent, age, distance and reddening. We find that the radius of NGC 6404 is 2.0-arcmin, as previously proposed, while the radius of NGC 6583 is 1.0 arcmin, significantly lower than previous estimates. Both clusters turn out to be of intermediate age (0.5-1.0Gyr old), and located inside the solar ring, at a Galactocentric distance of about 6.5kpc. These results make these objects very interesting targets for spectroscopic follow-up to measure their metallicity. In fact, they might allow us to enlarge by more than 1 kpc the baseline of the radial abundance gradient in the Galactic disc towards the Galactic Centre direction. This baseline is currently rather narrow especially for clusters of this age.
- ID:
- ivo://CDS.VizieR/J/AJ/122/1486
- Title:
- NGC 2451A proper motions and membership
- Short Name:
- J/AJ/122/1486
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide new evidence that NGC 2451A is undoubtedly a young open cluster, although sparsely populated. New cluster membership has been derived from relative proper motions of 5868 stars. In total, 136 stars down to V~15 5 have membership probability P{mu}>=2%. New CCD BV photometry indicates that about 70 stars are indeed main-sequence stars of NGC 2451A. This is also supported by our measurements of radial velocities. A total of 34 very likely cluster members yield a mean heliocentric radial velocity for NGC 2451A equal to +22.9km/s. The high quality of our BV photometry, a confirmation of cluster membership from proper motions and radial velocities, and a recently obtained metallicity estimate for several cluster stars allow us to perform a precise isochrone fit. The Yale isochrones, updated by the latest available input physics, have been fitted to the cluster's color-magnitude diagram, yielding a distance modulus V_0_-M_V_ in the range 6.35 to 6.38, which is in excellent agreement with the distance modulus (m-M)_0_=6.38 derived from the Hipparcos data recently by van Leeuwen and Robichon et al. (1998, Cat. <J/A+AS/130/157>). We have used the high-resolution spectra acquired using the Hydra multiobject spectrograph at the WIYN telescope (Kitt Peak, Arizona) in 1997 November and 1998 October.
- ID:
- ivo://CDS.VizieR/J/A+A/443/41
- Title:
- NGC 4038/4039 broad and /narrow band photometry
- Short Name:
- J/A+A/443/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Ks-band image which was used for the 3{sigma}-detection was obtained with ISAAC on VLT-ANTU as part of programme 65.N-0577, and has a FWHM of ~0.38". 1072 point-like objects were detected. For the multi-band photometry, we also used the HST archival images obtained by Whitmore et al. (see Whitmore et al., 1999AJ....118.1551W), which we rebinned to the same pixel size as the ISAAC image (0.1484"/pix). The CO narrow band image was also obtained with ISAAC, while the Br{gamma} image was obtained with SOFI at the NTT (programme number 63.N-0528). The Br{gamma} image had a lower image quality than the other two images (FWHM=0.7"). The photometry data were used to simultaneously fit age and extinction for each individual cluster in comparison to an evolutionary synthesis model. Where possible, the visual extinction was determined from an average of the extinction from the broadband fit and from the Hydrogen recombination line ratios (in comparison to the expected Case B line ratio). The age estimate from the fit was, where possible, averaged with the aged determined from equivalent widths and CO index.
4350. NGC 2213 BR photometry
- ID:
- ivo://CDS.VizieR/J/ApJ/297/582
- Title:
- NGC 2213 BR photometry
- Short Name:
- J/ApJ/297/582
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The age of the LMC red globular cluster NGC 2213 has been estimated as 1.3+/-0.5x10^9^yr from a color-magnitude diagram, derived from CCD photometry, that reveals the cluster main sequence. The accuracy of the age estimate, however, is limited by uncertainly in the LMC distance modulus, by uncertainty in the cluster metal abundance which appears to lie in the range one-half to one-sixth solar, by uncertainty in the reddening of the cluster, and by uncertainty in the extent to which the theoretical isochrones used for the age dating are affected by the neglect, in standard stellar models, of the interior mixing caused by convective overshoot in the stellar cores. Using the adopted reddening of E(B-V)=0.09 and assuming Y=0.2, isochrone best fits to the cluster main sequence are found for [M/H]=-0.3 if (m-M)0=18.7 and for [M/H]=-0.7 if (m-M)0=18.2. After allowance for the possible effects of convective overshoot, the corresponding ages are 0.9^+0.5^_-0.3_ and 1.6^+0.8_^-0.4_x10^9^yr. Plausible alterations in the adopted reddening value and the adopted helium abundance also yield ages within these limits.
