We present Atacama Large Millimeter/submillimeter Array (ALMA) observations from the 2014 Long Baseline Campaign in dust continuum and spectral line emission from the HL Tau region. The continuum images at wavelengths of 2.9, 1.3, and 0.87 mm have unprecedented angular resolutions of 0″. 075 (10 AU) to 0″. 025 (3.5 AU), revealing an astonishing level of detail in the circumstellar disk surrounding the young solar analog HL Tau, with a pattern of bright and dark rings observed at all wavelengths. By fitting ellipses to the most distinct rings, we measure precise values for the disk inclination (46 .72 0 .05 ± • •) and position angle (138 .02 0 .07).
Abstract. The AMIGA project (Analysis of the Interstellar Medium of Isolated Galaxies) is compiling a multiwavelength database of isolated galaxies that includes optical (B and Hα), infrared (FIR and NIR) and radio (continuum plus HI and CO lines) properties. It involves a refinement of the pioneering Catalog of Isolated Galaxies. This paper is the first in a series and begins with analysis of the global properties of the nearly redshift-complete CIG with emphasis on the Optical Luminosity Function (OLF) which we compare with other recent estimates of the OLF for a variety of environments. The CIG redshift distribution for n = 956 galaxies re-enforces the evidence for a bimodal structure seen earlier in smaller samples. The peaks at redshift near 1500 and 6000 km s −1 , corresponding respectively to galaxies in the local supercluster and those in more distant large-scale components (particularly Perseus-Pisces). The two peaks in the redshift distribution are superimposed on 50% or more of the sample that is distributed in a much more homogeneous way. The CIG probably represents the most homogeneous local field example that has ever been compiled. Our derivation of the CIG OLF is consistent with other studies of the OLF for lower density environments. This comparison via the Schechter parameter formalization shows that: 1) M * increases with galaxy surface density on the sky and 2) α shows a weaker tendency to do the same. The CIG represents the largest and most complete foundation for studies of isolated galaxies and is likely as close as we can come to a field sample.
We present a refinement of the optical morphologies for galaxies in the Catalog of Isolated Galaxies that forms the basis of the AMIGA (Analysis of the interstellar Medium of Isolated GAlaxies) project. Uniform reclassification using the digitized POSS II data benefited from the high resolution and dynamic range of that sky survey. Comparison with independent classifications made for an SDSS overlap sample of more than 200 galaxies confirms the reliability of the early vs. late-type discrimination and the accuracy of spiral subtypes within ∆T = 1-2. CCD images taken at the Observatorio de Sierra Nevada were also used to solve ambiguities in early versus late-type classifications. A considerable number of galaxies in the catalog (n = 193) are flagged for the presence of nearby companions or signs of distortion likely due to interaction. This most isolated sample of galaxies in the local Universe is dominated by two populations: 1) 82% are spirals (Sa-Sd) with the bulk being luminous systems with small bulges (63% between types Sb-Sc) and 2) a significant population of early-type E-S0 galaxies (14%). Most of the types later than Sd are low luminosity galaxies concentrated in the local supercluster where isolation is difficult to evaluate. The late-type spiral majority of the sample spans a luminosity range M B−corr = −18 to −22 mag. Few of the E/S0 population are more luminous than −21.0 marking the absence of the often-sought super L * merger (e.g. fossil elliptical) population. The rarity of high luminosity systems results in a fainter derived M * for this population compared to the spiral optical luminosity function (OLF). The E-S0 population is from 0.2 to 0.6 mag fainter depending on how the sample is defined. This marks the AMIGA sample as unique among samples that compare early and late-type OLFs separately. In other samples, which always involve galaxies in higher density environments, M * E/S0 is almost always 0.3-0.5 mag brighter than M * S , presumably reflecting a stronger correlation between M * and environmental density for early-type galaxies.
Aims. We describe the mid-(MIR) and far-(FIR) infrared properties of a large (∼1000) sample of the most isolated galaxies in the local Universe. This sample is intended as a "nurture-free" zero point against which more environmentally influenced samples can be compared. Methods. We reprocess IRAS MIR/FIR survey data using the ADDSCAN/SCANPI utility for 1030 out of 1050 galaxies from the Catalogue of Isolated Galaxies (CIG) as part of the AMIGA project. We focus on diagnostics (FIR luminosity L FIR , R = log(L FIR /L B ), and IRAS colours) thought to be sensitive to effects of environment or interaction.Results. The distribution of log(L FIR ) sharply peaks from 9.0-10.5, with very few (<2%) galaxies above 10.5. Review of available optical images of the most FIR luminous galaxies finds the majority likely to be interacting systems missed in our earlier morphological reevaluation. The optically normalised luminosity diagnostic R = log(L FIR /L B ) shows a sharply peaked distribution between 0.0 and −1.0. These results were compared to the magnitude limited sample of the Center for Astrophysics that was selected without environmental discrimination. This modestly (e.g., compared to cluster, binary galaxy, and compact group samples) environmentally affected sample shows a significantly higher mean log(L FIR ), and R, whereas the mean log(L B ) is the same. Our sample shows a strong L FIR vs. L B correlation, with a slope steeper than one (L FIR ∝ L 1.41 B ). Interacting galaxies were found above this correlation, showing an enhancement in L FIR . With respect to the IRAS colours, we found higher F 60 /F 100 values for ellipticals and late-type galaxies than for spirals, indicating a higher dust temperature. The mean value of F 60 /F 100 was found to be lower than for interacting samples from the literature. Conclusions. The results indicate that the FIR emission is a variable enhanced by interaction, and that our sample probably shows the lowest possible mean value. This attests to the utility of our sample for defining a nurture-free zero point.
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