We present the first colour–magnitude relation (CMR) of early‐type galaxies in the central region of the Antlia cluster, obtained from CCD wide‐field photometry in the Washington photometric system. Integrated (C−T1) colours, T1 magnitudes, and effective radii have been measured for 93 galaxies (i.e. the largest galaxies sample in the Washington system till now) from the FS90 Antlia Group catalogue. Membership of 37 objects can be confirmed through new radial velocities and data collected from the literature. The resulting colour–magnitude diagram shows that early‐type FS90 galaxies that are spectroscopically confirmed Antlia members or that were considered as definite members by FS90, follow a well‐defined CMR that spans 9 mag in brightness with no apparent change of slope. This relation is very tight for the whole magnitude range but S0 galaxies show a larger dispersion, apparently due to a separation of ellipticals and S0s. Antlia displays a slope of −13.6 in a T1 versus (C−T1) diagram, in agreement with results for clusters like Fornax, Virgo, Coma and Perseus, which are dynamically different to Antlia. This fact might indicate that the build‐up of the CMR in cluster of galaxies is more related to galaxies internal processes than to the influence of the environment. Interpreting the CMR as a luminosity–metallicity relation of old stellar systems, the metallicities of the Antlia galaxies define a global relation down to MV≈−13. We also find, for early‐type dwarfs, no clear relation between luminosity and effective radius, indicating a nearly constant mean effective radius of ∼1 kpc. This value is also found in several samples of dwarf galaxies in Virgo and Coma.
Based in part on observations made with ESO telescopes at Paranal and APEX Observatories, under ESO programs 083.C-0459(A), 085.C-0571(D), 083.F-0162(A). This paper includes data gathered with the 6.5-m Magellan Telescopes located at Las Campanas Observatory. AbstractTransition disk objects are pre-main-sequence stars with little or no near-IR excess and significant far-IR excess, implying inner opacity holes in their disks.Here we present a multifrequency study of transition disk candidates located in Lupus I, III, IV, V, VI, Corona Australis, and Scorpius. Complementing the information provided by Spitzer with Adaptive Optics (AO) imaging (NaCo, VLT), submillimeter photometry (APEX), and echelle spectroscopy (Magellan, Du Pont Telescopes), we estimate the multiplicity, disk mass, and accretion rate for each object in our sample in order to identify the mechanism potentially responsible for its inner hole. We find that our transition disks show a rich diversity in their SED morphology, have disk masses ranging from < ∼ 1 to 10 M JUP and accretion rates ranging from < ∼ 10 −11 to 10 −7.7 M yr −1 . Of the 17 bona fide transition disks in our sample, 3, 9, 3, and 2 objects are consistent with giant planet formation, grain growth, photoevaporation, and debris disks, respectively. Two disks could be circumbinary, which offers tidal truncation as an alternative origin of the inner hole. We find the same heterogeneity of the transition disk population in Lupus III, IV, and Corona Australis as in our previous analysis of transition disks in Ophiuchus while all transition disk candidates selected in Lupus V, VI turned out to be contaminating background AGB stars. All transition disks classified as photoevaporating disks have small disk masses, which indicates that photoevaporation must be less efficient than predicted by most recent models. The three systems that are excellent candidates for harboring giant planets potentially represent invaluable laboratories to study planet formation with the Atacama Large Millimeter/Submillimeter Array.. Subject headings: accretion disk -binaries: general -line: identification -planetary systems: protoplanetary disks -stars: pre-main sequence a b " · · · " implies that the signal to noise in this region of the spectrum is too low to measure the width or establish the presence of the line c "-1" implies that Hα is seen in absorption. d "<" implies upper limits value (3 σ) e Sources # 1, 3, 4, and 9 have been identified as binaries by WFI observations . The binary nature of source # 14 was discovered using speckle interferometry at the NTT (La Silla) revealing a projected separation of 0.132 ± 0.009 (Köhler et al. 2008). Sources # 11, 13 are triple systems with tight binary components consistent with two equally bright objects and a projected separation of ∼0.05 .f The spectral type derived by us is significantly later than the previously obtained value. We consider our estimate of M5.25 based on a high quality optical spectrum to be more reliable than the rather rough guess of Merín et...
The Southern Photometric Local Universe Survey (S-PLUS) is imaging ∼9300 deg2 of the celestial sphere in 12 optical bands using a dedicated 0.8 m robotic telescope, the T80-South, at the Cerro Tololo Inter-american Observatory, Chile. The telescope is equipped with a 9.2k × 9.2k e2v detector with 10 $\rm {\mu m}$ pixels, resulting in a field of view of 2 deg2 with a plate scale of 0.55 arcsec pixel−1. The survey consists of four main subfields, which include two non-contiguous fields at high Galactic latitudes (|b| > 30°, 8000 deg2) and two areas of the Galactic Disc and Bulge (for an additional 1300 deg2). S-PLUS uses the Javalambre 12-band magnitude system, which includes the 5 ugriz broad-band filters and 7 narrow-band filters centred on prominent stellar spectral features: the Balmer jump/[OII], Ca H + K, H δ, G band, Mg b triplet, H α, and the Ca triplet. S-PLUS delivers accurate photometric redshifts (δz/(1 + z) = 0.02 or better) for galaxies with r < 19.7 AB mag and z < 0.4, thus producing a 3D map of the local Universe over a volume of more than $1\, (\mathrm{Gpc}/h)^3$. The final S-PLUS catalogue will also enable the study of star formation and stellar populations in and around the Milky Way and nearby galaxies, as well as searches for quasars, variable sources, and low-metallicity stars. In this paper we introduce the main characteristics of the survey, illustrated with science verification data highlighting the unique capabilities of S-PLUS. We also present the first public data release of ∼336 deg2 of the Stripe 82 area, in 12 bands, to a limiting magnitude of r = 21, available at datalab.noao.edu/splus.
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