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We exploit the gravitational potential of a massive, rich cluster at to study the internal properties of a gravitationally lensed galaxy at . Using high-resolution Hubble Space Telescope imaging together with optical (VIMOS) and near-infrared (SINFONI) integral field spectroscopy, we have studied the rest-frame ultraviolet and optical properties of the lensed galaxy seen through the cluster RCS0224−002. Using a detailed gravitational lens model of the cluster, we reconstruct the source-frame morphology on 200 pc scales and find an Lyman-break galaxy with an intrinsic size of only , a velocity gradient of and an implied dynamical mass of within 2 kpc. We infer an integrated star formation rate of just from the intrinsic [O ii]λ3727 emission-line flux. The Lyα emission appears redshifted by with respect to the [O ii] emission. The Lyα is also significantly more extended than the nebular emission, extending over 11.9 × 2.4 kpc. Over this area, the Lyα centroid varies by less than . We model the asymmetric Lyα emission with an underlying Gaussian profile with an absorber in the blue wing and find that the underlying Lyα emission-line centroid is in excellent agreement with the [O ii] emission-line redshift. By examining the spatially resolved structure of the [O ii] and Lyα emission lines, we investigate the nature of this system. The model for local starburst galaxies suggested by Mas-Hesse et al. provides a good description of our data, and suggests that the galaxy is surrounded by a galactic-scale bipolar outflow which has recently bursted out of the system. The outflow, which appears to be currently located ≳30 kpc from the galaxy, is escaping at a speed of upto . Although the mass of the outflow is uncertain, the geometry and velocity of the outflow suggests that the ejected material is travelling far faster than escape velocity and will travel more than 1 Mpc (comoving) before eventually stalling. [ABSTRACT FROM AUTHOR]

We present optical integral field spectroscopy of the Hα-luminous central cluster galaxies in the cores of the cooling flow clusters A1664, A1835, A2204 and Zw8193. From the [N ii]+Hα complex in these moderate resolution (70–150 km s−1) spectra we derive 2D views of the distribution and kinematics of the emission-line gas, and further diagnostics from the [S ii] and [O i] lines. The Hα emission shows a variety of disturbed morphologies, ranging from smooth but distorted to clumpy and filamentary, with velocity gradients and splittings of several hundred km s−1 on spatial scales of 20 kpc or more. Despite the small sample size, there are some generic features. The most disturbed Hα emission appears to be associated with secondary galaxies within 10–20 kpc (projected) of the central galaxy and close in velocity to the Hα. The global Hα kinematics match those of the CO(1–0) emission in single-dish data. The [N ii]/Hα, [S ii]/Hα and [O i]/Hα ratios vary little with position, local Hα surface brightness or between clusters. We propose that the Hα and CO emission arise in molecular clouds heated by a starburst, and that the latter has been triggered by interaction with a secondary galaxy. Such CO emission is known to trace massive compact (<20 kpc) reservoirs of cool molecular gas, and it is plausible that an infalling galaxy would disturb this gas, distorting the Hα morphology and initiating widespread star formation. We also examine the role of cloud–cloud collisions in the undisturbed molecular gas reservoir, and suggest that they might be an important source of excitation for the emission-line gas in the cores of lower Hα luminosity clusters with less intense star formation. [ABSTRACT FROM AUTHOR]

We have used the SAURON panoramic integral field spectrograph to study the structure of the Lyα emission-line halo, LAB1, surrounding the submillimetre galaxy SMM J221726+0013. This emission-line halo was discovered during a narrow-band imaging survey of the large-scale structure in the SSA 22 region. Our observations trace the emission halo out to almost 100 kpc from the submillimetre source and identify two distinct Lyα‘mini-haloes’ around the nearby Lyman-break galaxies. The main emission region has a broad line profile, with variations in the line profile seeming chaotic and lacking evidence for a coherent velocity structure. The data also suggest that Lyα emission is suppressed around the submillimetre source. Interpretation of the line structure needs care because Lyα may be resonantly scattered, leading to complex radiative transfer effects, and we suggest that the suppression in this region arises because of such effects. We compare the structure of the central emission-line halo with local counterparts, and find that the emission-line halo around NGC 1275 in the Perseus cluster may be a good local analogue, although the high-redshift halo is factor of ∼100 more luminous and appears to have higher velocity broadening. Around the Lyman-break galaxy C15, the emission line is narrower, and a clear shear in the emission wavelength is seen. A plausible explanation for the line profile is that the emission gas is expelled from C15 in a bipolar outflow, similar to that seen in M82. [ABSTRACT FROM AUTHOR]

High-velocity galactic outflows, driven by intense bursts of star formation and black hole accretion, are processes invoked by current theories of galaxy formation to terminate star formation in the most massive galaxies and to deposit heavy elements in the intergalactic medium. From existing observational evidence (for high-redshift galaxies) it is unclear whether such outflows are localized to regions of intense star formation just a few kiloparsecs in extent, or whether they instead have a significant impact on the entire galaxy and its surroundings. Here we present two-dimensional spectroscopy of a star-forming galaxy at redshift z = 3.09 (seen 11.5 gigayears ago, when the Universe was 20 per cent of its current age): its spatially extended Lyα line emission appears to be absorbed by H i in a foreground screen covering the entire galaxy, with a lateral extent of at least 100 kpc and remarkable velocity coherence. This screen was ejected from the galaxy during a starburst several 108 years earlier and has subsequently swept up gas from the surrounding intergalactic medium and cooled. This demonstrates the galaxy-wide impact of high-redshift superwinds. [ABSTRACT FROM AUTHOR]

We present wide area, deep, high-resolution 153 MHz GMRT observations of the NOAO Boötes field, adding to the extensive, multiwavelength data of this region. The observations, data reduction, and catalogue construction and description are described here. The seven pointings produced a final mosaic covering 30 square degrees with a resolution of 25″ . The rms noise is 2 mJy beam-1 in the centre of the image, rising to 4-5 mJy beam-1 on the edges, with an average of 3 mJy beam-1. Seventy-five per cent of the area has an rms < 4 mJy beam-1. The extracted source catalogue contains 1289 sources detected at 5 σ, of which 453 are resolved. We estimate the catalogue to be 92 per cent reliable and 95 per cent complete at an integrated flux density limit of 14 mJy. The flux densities and astrometry have been corrected for systematic errors. We calculate the differential source counts, which are in good agreement with those in the literature and provide an important step forward in quantifying the source counts at these low frequencies and low flux densities. The GMRT 153 MHz sources have been matched to the 1.4 GHz NVSS and 327 MHz WENSS catalogues and spectral indices were derived. [ABSTRACT FROM AUTHOR]

We describe the number counts and spatial distribution of 239 distant red galaxies (DRGs), selected from the Early Data Release of the UKIDSS Ultra Deep Survey. The DRGs are identified by their very red infrared colours with , selected over 0.62 deg2 to a 90 per cent completeness limit of . This is the first time that a large sample of bright DRGs has been studied within a contiguous area, and we provide the first measurements of their number counts and clustering. The population shows strong angular clustering, intermediate between those of K-selected field galaxies and optical/infrared-selected extremely red galaxies. Adopting the redshift distributions determined from other recent studies, we infer a high correlation length of . Such strong clustering could imply that our galaxies are hosted by very massive dark matter haloes, consistent with the progenitors of present-day elliptical galaxies. [ABSTRACT FROM AUTHOR]

We present a ≈20 ks Chandra ACIS-S observation of the strongly lensed ultraluminous infrared galaxy FSC 10214 + 4724. Although this observation achieves the equivalent sensitivity of an up to ≈4 Ms Chandra exposure (when corrected for gravitational lensing), the rest-frame 1.6–26.3 keV emission from FSC 10214 + 4724 is weak ( for a lensing boost of ≈100); a significant fraction of this X-ray emission appears to be due to vigorous star formation activity. If FSC 10214 + 4724 hosts a quasar, as previously suggested, then it must be obscured by Compton-thick material. We compare FSC 10214 + 4724 to high-redshift SCUBA galaxies and discuss the X-ray identification of Compton-thick AGNs at high redshift. [ABSTRACT FROM AUTHOR]

We present Low Frequency Array (LOFAR) Low Band observations of the Boötes and 3C 295 fields. Our images made at 34, 46, and 62 MHz reach noise levels of 12, 8, and 5 mJy beam–1, making them the deepest images ever obtained in this frequency range. In total, we detect between 300 and 400 sources in each of these images, covering an area of 17-52 deg2. From the observations, we derive Euclidean-normalized differential source counts. The 62 MHz source counts agree with previous GMRT 153 MHz and Very Large Array 74 MHz differential source counts, scaling with a spectral index of –0.7. We find that a spectral index scaling of –0.5 is required to match up the LOFAR 34 MHz source counts. This result is also in agreement with source counts from the 38 MHz 8C survey, indicating that the average spectral index of radio sources flattens toward lower frequencies. We also find evidence for spectral flattening using the individual flux measurements of sources between 34 and 1400 MHz and by calculating the spectral index averaged over the source population. To select ultra-steep spectrum (α < –1.1) radio sources that could be associated with massive high-redshift radio galaxies, we compute spectral indices between 62 MHz, 153 MHz, and 1.4 GHz for sources in the Boötes field. We cross-correlate these radio sources with optical and infrared catalogs and fit the spectral energy distribution to obtain photometric redshifts. We find that most of these ultra-steep spectrum sources are located in the 0.7 ≲ z ≲ 2.5 range. [ABSTRACT FROM AUTHOR]

We present X-ray observations of the hyperluminous infrared galaxy (HLIRG) IRAS 00182− 7112 obtained using the XMM–Newton EPIC camera. A luminous hard X-ray source coincident with the nucleus is revealed, along with weaker soft X-ray emission which may be extended or offset from the hard emission. The EPIC spectrum is extremely flat and shows Fe Kα emission with very high equivalent width: both are typical characteristics of a buried, Compton-thick active galactic nucleus (AGN) which is seen only in scattered light. Perhaps the most remarkable characteristic of the spectrum is that the Fe Kα line energy is that of He-like iron, making IRAS 00182−7112 the first hidden AGN known to be dominated by ionized, Compton-thick reflection. Taking an appropriate bolometric correction, we find that this AGN could easily dominate the far-infrared (FIR) energetics. The nuclear reflection spectrum is seen through a relatively cold absorber with column density consistent with recent Spitzer observations. The soft X-ray emission, which may be thermal in nature and associated with star-forming activity, is seen unabsorbed. The soft X-rays and weak polycyclic aromatic hydrocarbon features both give estimates of the star formation rate , insufficient to power the FIR emission and supportive of the idea that this HLIRG is AGN-dominated. [ABSTRACT FROM AUTHOR]