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.

Near-Infrared Bright Galaxies at z ≃ 2. Entering the Spheroid Formation Epoch?*

Abstract: Spectroscopic redshifts have been measured for nine K-band luminous galaxies at 1.7 < z < 2.3, selected with Ks < 20 in the K20 survey region of the Great Observatories Origins Deep Survey (GOODS) area. Star formation rates (SFRs) of ~100-500 M? yr-1 are derived when dust extinction is taken into account. The fitting of their multicolor spectral energy distributions indicates stellar masses of M 1011 M? for most of the galaxies. Their rest-frame UV morphology is highly irregular, suggesting that merging-driven starbursts are going on in these galaxies. Morphologies tend to be more compact in the near-IR, a hint for the possible presence of older stellar populations. Such galaxies are strongly clustered, with seven out of nine belonging to redshift spikes, which indicates a correlation length of r0 ~ 9-17 h-1 Mpc (1 ? range). Current semianalytical models of galaxy formation appear to underpredict by a large factor (30) the number density of such a population of massive and powerful starburst galaxies at z ~ 2. The high masses and SFRs, together with the strong clustering, suggest that at z ~ 2 we may have started to explore the major formation epoch of massive early-type galaxies.

DETECTION OF ATOMIC CARBON [C II] 158 μm AND DUST EMISSION FROM A z 7.1 QUASAR HOST GALAXY

Abstract: Using the IRAM Plateau de Bure Interferometer, we report the detection of the 158 {mu}m [C II] emission line and underlying dust continuum in the host galaxy of the quasar ULAS J112001.48+064124.3 (hereafter J1120+0641) at z 7.0842 {+-} 0.0004. This is the highest redshift detection of the [C II] line to date, and allows us to put the first constraints on the physical properties of the host galaxy of J1120+0641. The [C II] line luminosity is 1.2 {+-} 0.2 Multiplication-Sign 10{sup 9} L{sub Sun }, which is a factor {approx}4 lower than observed in a luminous quasar at z = 6.42 (SDSS J1148+5251). The underlying far-infrared (FIR) continuum has a flux density of 0.61 {+-} 0.16 mJy, similar to the average flux density of z {approx} 6 quasars that were not individually detected in the rest-frame FIR. Assuming that the FIR luminosity of L{sub FIR} = 5.8 Multiplication-Sign 10{sup 11}-1.8 Multiplication-Sign 10{sup 12} L{sub Sun} is mainly powered by star formation, we derive a star formation rate in the range 160-440 M{sub Sun} yr{sup -1} and a total dust mass in the host galaxy of 6.7 Multiplication-Sign 10{sup 7}-5.7 Multiplication-Sign 10{sup 8} M{sub Sun} (both numbers have significant uncertainties givenmore » the unknown nature of dust at these redshifts). The [C II] line width of {sigma}{sub V} = 100 {+-} 15 km s{sup -1} is among the smallest observed when compared to the molecular line widths detected in z {approx} 6 quasars. Both the [C II] and dust continuum emission are spatially unresolved at the current angular resolution of 2.0 Multiplication-Sign 1.7 arcsec{sup 2} (corresponding to 10 Multiplication-Sign 9 kpc{sup 2} at the redshift of J1120+0641).« less

Type Ia Supernovae

Abstract: Type Ia Supernovae are in many aspects still enigmatic objects. Their observational and theoretical exploration is in full swing, but we still have plenty to learn about these explosions. Recent years have already witnessed a bonanza of supernova observations. The increased samples from dedicated searches have allowed the statistical investigation of Type Ia Supernovae as a class. The observational data on Type Ia Supernovae are very rich, but the uniform picture of a decade ago has been replaced by several correlations which connect the maximum luminosity with light curve shape, color evolution, spectral appearance, and host galaxy morphology. These correlations hold across almost the complete spectrum of Type Ia Supernovae, with a number of notable exceptions. After 150 days past maximum, however, all observed objects show the same decline rate and spectrum. The observational constraints on explosion models are still rather sparse. Global parameters like synthesized nickel mass, total ejecta mass and explosion energetics are within reach in the next few years. These parameters bypass the complicated calculations of explosion models and radiation transport. The bolometric light curves are a handy tool to investigate the overall appearance of Type Ia Supernovae. The nickel masses derived this way show large variations, which combined with the dynamics from line widths, indicate that the brighter events are also coming from more massive objects. The lack of accurate distances and the uncertainty in the correction for absorption are hampering further progress. Improvements in these areas are vital for the detailed comparison of luminosities and the determination of nickel masses. Coverage at near-infrared wavelengths for a statistical sample of Type Ia Supernovae will at least decrease the dependence on the absorption. Some of the most intriguing features of Type Ia Supernovae are best observed at these wavelengths, like the second peak in the light curve, the depression in the J band, and the unblended [Feii] lines in the ashes.

Aerosol classification by airborne high spectral resolution lidar observations

Abstract: . During four aircraft field experiments with the DLR research aircraft Falcon in 1998 (LACE), 2006 (SAMUM-1) and 2008 (SAMUM-2 and EUCAARI), airborne High Spectral Resolution Lidar (HSRL) and in situ measurements of aerosol microphysical and optical properties were performed. Altogether, the properties of six different aerosol types and aerosol mixtures – Saharan mineral dust, Saharan dust mixtures, Canadian biomass burning aerosol, African biomass burning mixture, anthropogenic pollution aerosol, and marine aerosol have been studied. On the basis of this extensive HSRL data set, we present an aerosol classification scheme which is also capable to identify mixtures of different aerosol types. We calculated mixing lines that allowed us to determine the contributing aerosol types. The aerosol classification scheme was supported by backward trajectory analysis and validated with in-situ measurements. Our results demonstrate that the developed aerosol mask is capable to identify complex stratifications with different aerosol types throughout the atmosphere.

Unveiling a rich system of faint dwarf galaxies in the next generation fornax survey

Abstract: We report the discovery of 158 previously undetected dwarf galaxies in the Fornax cluster central regions using a deep coadded $u, g$ and $i$-band image obtained with the DECam wide-field camera mounted on the 4-meter Blanco telescope at the Cerro Tololo Interamerican Observatory as part of the {\it Next Generation Fornax Survey} (NGFS). The new dwarf galaxies have quasi-exponential light profiles, effective radii $0.1\! \!75\%$ at luminosities brighter than $M_i\!\simeq\!-15.0$ mag to $0\%$ at luminosities fainter than $M_i\!\simeq\!-10.0$ mag. The two-point correlation function analysis of the NGFS dwarf sample shows an excess on length scales below $\sim\!100$ kpc, pointing to the clustering of dwarf galaxies in the Fornax cluster core.