The A2667 Giant Arc at z=1.03: Evidence for Large-scale Shocks at High Redshift

We present the spatially resolved emission line ratio properties of a ~10^10 M_sun star-forming galaxy at redshift z=1.03. This galaxy is gravitationally lensed as a triple-image giant arc behind the massive lensing cluster Abell 2667. The main image of the galaxy has magnification factors of 14+/-2.1 in flux and ~ 2 by 7 in area, yielding an intrinsic spatial resolution of 115-405 pc after AO correction with OSIRIS at KECK II. The HST morphology shows a clumpy structure and the H\alpha\ kinematics indicates a large velocity dispersion with V_{max} sin(i)/\sigma ~ 0.73, consistent with high redshift disk galaxies of similar masses. From the [NII]/H\alpha\ line ratios, we find that the central 350 parsec of the galaxy is dominated by star formation. The [NII]/H\alpha\ line ratios are higher in the outer-disk than in the central regions. Most noticeably, we find a blue-shifted region of strong [NII]/H\alpha\ emission in the outer disk. Applying our recent HII region and slow-shock models, we propose that this elevated [NII]/H\alpha\ ratio region is contaminated by a significant fraction of shock excitation due to galactic outflows. Our analysis suggests that shocked regions may mimic flat or inverted metallicity gradients at high redshift.Comment: 11 pages, 9 figures, ApJ accepte

CC116 Suggestions for Handling Summer Fallowed Land which will not be Planted to Winter Wheat

Extension Circular CC116 This circular contains suggestions for handling summer fallowed land which will not be planted to winter wheat

CC180 Revised 1961 Castorbean Production in Nebraska

Campaign Circulation 180R is about Castorbean production in Nebraska 1961

EC58-123 Questions and Answers about Stubble Mulching

Extension Circular 58-123 provides questions and answers about Stubble Mulch farming

GMOS Integral Field Spectroscopy of a Merging System with Enhanced Balmer Absorption

In this paper we present the three dimensional dynamics of the galaxy SDSS J101345.39+011613.66, selected for its unusually strong Balmer absorption lines (Wo(H-delta)=7.5A). Using the GMOS-South IFU in Nod & Shuffle mode we have mapped the continuum and optical absorption lines of this z=0.1055 field galaxy. This galaxy has a disturbed morphology, with a halo of diffuse material distributed asymmetrically toward the north. Using the [OII] emission line (Wo([OII])=4.1A) we find that the gas and hot OB stars are offset from the older stars in the system. The gas also has a spatially extended and elongated morphology with a velocity gradient of 100+/-20km/s across 6kpc in projection. Using the strong H-gamma and H-delta absorption lines we find that the A- stars are widely distributed across the system and are not centrally concentrated arguing that the A-star population has formed in molecular clouds outside the nucleus. By cross correlating the spectra from the datacube with an A-star template we find evidence that the A-star population has a 40km/s shear in the same direction as the gas. The disturbed morphology, strong colour gradients and strong H-delta and H-gamma absorption lines in SDSS J101345.39 argue that this is a recent tidal interaction/merger between a passive elliptical and star-forming galaxy. Although based on a single object, these results show that we can spatially resolve and constrain the dynamics of this short lived (yet important) phase of galaxy formation in which the evolutionary process take galaxies from star-forming to their quiescent end products.Comment: 7 pages, 7 figures. Accepted for publication in Ap

A comparison of the strong lensing properties of the Sersic and the NFW profiles

We investigate the strong lensing properties of the Sersic profile as an alternative to the NFW profile, focusing on applications to lens modelling of clusters. Given an underlying Sersic dark matter profile, we study whether an NFW profile can provide an acceptable fit to strong lensing constraints in the form of single or multiple measured Einstein radii. We conclude that although an NFW profile that fits the lensing constraints can be found in many cases, the derived parameters may be biased. In particular, we find that for n~2, which corresponds to massive clusters, the mass at r_200 of the best fit NFW is overestimated (by a factor of ~2) and the concentration is very low (c~2). The differences are important enough to warrant the inclusion of Sersic profile for future analysis of strong lensing clusters.Comment: 19 pages (single column format), 11 figures. Accepted for publication by JCA

High Sensitivity Array Observations of the z=1.87 Sub-Millimeter Galaxy GOODS 850-3

We present sensitive phase-referenced VLBI results on the radio continuum emission from the z=1.87 luminous submillimeter galaxy (SMG) GOODS 850-3. The observations were carried out at 1.4 GHz using the High Sensitivity Array (HSA). Our sensitive tapered VLBI image of GOODS 850-3 at 0.47 x 0.34 arcsec (3.9 x 2.9 kpc) resolution shows a marginally resolved continuum structure with a peak flux density of 148 \pm 38 uJy/beam, and a total flux density of 168 \pm 73 uJy, consistent with previous VLA and MERLIN measurements. The derived intrinsic brightness temperature is > 5 \pm 2 x 10^3 K. The radio continuum position of this galaxy coincides with a bright and extended near-infrared source that nearly disappears in the deep HST optical image, indicating a dusty source of nearly 9 kpc in diameter. No continuum emission is detected at the full VLBI resolution (13.2 x 7.2 mas, 111 x 61 pc), with a 4-sigma point source upper limit of 26 uJy/beam, or an upper limit to the intrinsic brightness temperature of 4.7 x 10^5 K. The extent of the observed continuum source at 1.4 GHz and the derived brightness temperature limits are consistent with the radio emission (and thus presumably the far-infrared emission) being powered by a major starburst in GOODS 850-3, with a star formation rate of ~2500 M_sun/yr. Moreover, the absence of any continuum emission at the full resolution of the VLBI observations indicates the lack of a compact radio AGN source in this z=1.87 SMG.Comment: 19 pages, 4 figures, accepted for publication in A

Integral field spectroscopy with SINFONI of VVDS galaxies. I. Galaxy dynamics and mass assembly at 1.2 < z < 1.6

Context. Identifying the main processes of galaxy assembly at high redshifts is still a major issue to understand galaxy formation and evolution at early epochs in the history of the Universe. Aims. This work aims to provide a first insight into the dynamics and mass assembly of galaxies at redshifts 1.2<z<1.6, the early epoch just before the sharp decrease of the cosmic star formation rate. Methods. We use the near-infrared integral field spectrograph SINFONI on the ESO-VLT under 0.65 seeing to obtain spatially resolved spectroscopy on nine emission line galaxies with 1.2<z<1.6 from the VIMOS VLT Deep Survey. We derive the velocity fields and velocity dispersions on kpc scales using the Halpha emission line. Results. Out of the nine star-forming galaxies, we find that galaxies distribute in three groups: two galaxies can be well reproduced by a rotating disk, three systems can be classified as major mergers and four galaxies show disturbed dynamics and high velocity dispersion. We argue that there is evidence for hierarchical mass assembly from major merger, with most massive galaxies with M>10^11Msun subject to at least one major merger over a 3 Gyr period as well as for continuous accretion feeding strong star formation. Conclusions. These results point towards a galaxy formation and assembly scenario which involves several processes, possibly acting in parallel, with major mergers and continuous gas accretion playing a major role. Well controlled samples representative of the bulk of the galaxy population at this key cosmic time are necessary to make further progress.Comment: 23 pages, 22 figures, accepted for publication in A&