European Southern Observatory

About: European Southern Observatory is a facility organization based out in Garching bei München, Germany. It is known for research contribution in the topics: Galaxy & Stars. The organization has 3594 authors who have published 16157 publications receiving 823095 citations. The organization is also known as: The European Southern Observatory，ESO & ESO.

Mapping the interstellar dust with near-infrared observations: An optimized multi-band technique

Abstract: We generalize Lada et al. (1994) Nice technique to map dust column density through a molecular cloud to an optimized multi-band technique that can be applied to any multi-band survey of molecular clouds. We present a first application to a ~ 625 deg2 subset of the Two Micron All Sky Survey (2MASS) data and show that when compared to Nice, the optimized Nicer (i) achieves the same extinction peak values, (ii) improves the noise variance of the map by a factor of 2 and (iii) is able to reach 3σ dust extinction measurements as low as A V ≃ 0.5 magnitudes, better than or equivalent to classical optical star count techniques and below the threshold column density for the formation of CO.

astroquery: An Astronomical Web-querying Package in Python

Abstract: Astroquery is a collection of tools for requesting data from databases hosted on remote servers with interfaces exposed on the Internet, including those with web pages but without formal application program interfaces. These tools are built on the Python requests package, which is used to make HTTP requests, and astropy, which provides most of the data parsing functionality. astroquery modules generally attempt to replicate the web page interface provided by a given service as closely as possible, making the transition from browser-based to command-line interaction easy. astroquery has received significant contributions from throughout the astronomical community, including several from telescope archives. astroquery enables the creation of fully reproducible workflows from data acquisition through publication. This paper describes the philosophy, basic structure, and development model of the astroquery package. The complete documentation for astroquery can be found at http://astroquery.readthedocs.io/.

The building blocks of planets within the ‘terrestrial’ region of protoplanetary disks

Abstract: Our Solar System was formed from a cloud of gas and dust. Most of the dust mass is contained in amorphous silicates, yet crystalline silicates are abundant throughout the Solar System, reflecting the thermal and chemical alteration of solids during planet formation. (Even primitive bodies such as comets contain crystalline silicates.) Little is known about the evolution of the dust that forms Earth-like planets. Here we report spatially resolved detections and compositional analyses of these building blocks in the innermost two astronomical units of three proto-planetary disks. We find the dust in these regions to be highly crystallized, more so than any other dust observed in young stars until now. In addition, the outer region of one star has equal amounts of pyroxene and olivine, whereas the inner regions are dominated by olivine. The spectral shape of the inner-disk spectra shows surprising similarity with Solar System comets. Radial-mixing models naturally explain this resemblance as well as the gradient in chemical composition. Our observations imply that silicates crystallize before any terrestrial planets are formed, consistent with the composition of meteorites in the Solar System.

Extrasolar planet population synthesis. II. Statistical comparison with observations

Abstract: Context. This is the second paper in a series of papers showing the results of extrasolar planet population synthesis calculations using our extended core accretion model. In the companion paper (Paper I), we have presented in detail the methods we use. In subsequent papers, we shall discuss the e ect of the host star’s mass on the planetary population and the influence of various properties of protoplanetary disks. Aims. In this second paper, we focus on planets orbiting solar-like stars. The goal is to use the main characteristics of the actually observed extrasolar planet population to derive in a statistical manner constraints on the planet formation models. Methods. Drawing initial conditions for our models at random from probability distributions derived as closely as possible from observations, we synthesize a number of planetary populations. By applying an observational detection bias appropriate for radial velocity surveys, we identify the potentially detectable synthetic planets. The properties of these planets are compared in quantitative statistical tests with the properties of a carefully selected sub-population of actually observed extrasolar planets. Results. We use a two dimensional Kolmogorov-Smirnov test to compare the mass-distance distributions of synthetic and observed planets, as well as the one dimensional version of the test to compare the M sini, the semimajor axis and the [Fe/H] distribution. We find that while many combinations of parameters lead to unacceptable distributions, a number of models can account to a reasonable degree of statistical significance for most of the properties of the observed sample. We concurrently account for many other observed features, e.g. the “metallicity e ect”. This gives us confidence that our model captures several essential features of giant planet formation. In addition, the fact that many parameter combination could be rejected, indicates that planet population synthesis is indeed a promising approach to constrain formation models. Our simulations allow us also to extract a number of properties of the underlying exoplanet population that are not yet directly detectable. For example, we have derived the planetary initial mass function (PIMF) and have been led to conclude that the planets detected so far represent only the tip of the iceberg (9%) of all the existing planets. The PIMF can also be used to predict how the detectable extrasolar planet population will change as the instrumental precision of radial velocity surveys improves from 10 m/s to 1 m/s, or even to an extreme precision of 0.1 m/s.

An ALMA survey of sub-millimetre Galaxies in the Extended Chandra Deep Field South: the far-infrared properties of SMGs

Abstract: We exploit Atacama Large Millimeter Array (ALMA) 870 mu m observations of sub-millimetre sources in the Extended Chandra Deep Field South to investigate the far-infrared properties of high-redshift sub-millimetre galaxies (SMGs). Using the precisely located 870 mu m ALMA positions of 99 SMGs, together with 24 mu m and radio imaging, we deblend the Herschel/SPIRE imaging to extract their far-infrared fluxes and colours. The median redshifts for ALMA LESS (ALESS) SMGs which are detected in at least two SPIRE bands increases with wavelength of the peak in their spectral energy distributions (SEDs), with z = 2.3 +/- 0.2, 2.5 +/- 0.3 and 3.5 +/- 0.5 for the 250, 350 and 500 mu m peakers, respectively. 34 ALESS SMGs do not have a >3 sigma counterpart at 250, 350 or 500 mu m. These galaxies have a median photometric redshift derived from the rest-frame UV-mid-infrared SEDs of z = 3.3 +/- 0.5, which is higher than the full ALESS SMG sample; z = 2.5 +/- 0.2. We estimate the far-infrared luminosities and characteristic dust temperature of each SMG, deriving L-IR = (3.0 +/- 0.3) x 10(12) L-circle dot (SFR = 300 +/- 30 M-circle dot yr(-1)) and T-d = 32 +/- 1 K. The characteristic dust temperature of these high-redshift SMGs is Delta T-d = 3-5K lower than comparably luminous galaxies at z = 0, reflecting the more extended star formation in these systems. We show that the contribution of S-870 mu m >= 1 mJy SMGs to the cosmic star formation budget is 20 per cent of the total over the redshift range z similar to 1-4. Adopting an appropriate gas-to-dust ratio, we estimate a typical molecular mass of the ALESS SMGs of M-H2 = (4.2 +/- 0.4) x 10(10) M-circle dot. Finally, we show that SMGs with S-870 mu m > 1 mJy (L-IR greater than or similar to 10(12) L-circle dot) contain similar to 10 per cent of the z similar to 2 volume-averaged H-2 mass density.