ZFOURGE catalogue of AGN candidates: an enhancement of 160-μm-derived star formation rates in active galaxies to z = 3.2

We investigate active galactic nuclei (AGN) candidates within the FourStar Galaxy Evolution Survey (ZFOURGE) to determine the impact they have on star formation in their host galaxies. We first identify a population of radio, X-ray, and infrared-selected AGN by cross-matching the deep Ks-band imaging of ZFOURGE with overlapping multiwavelength data. From this, we construct a mass-complete (log(M∗/M⊙M∗/M⊙) ≥9.75), AGN luminosity limited sample of 235 AGN hosts over z = 0.2–3.2. We compare the rest-frame U − V versus V − J (UVJ) colours and specific star formation rates (sSFRs) of the AGN hosts to a mass-matched control sample of inactive (non-AGN) galaxies. UVJ diagnostics reveal AGN tend to be hosted in a lower fraction of quiescent galaxies and a higher fraction of dusty galaxies than the control sample. Using 160 μm Herschel PACS data, we find the mean specific star formation rate of AGN hosts to be elevated by 0.34 ± 0.07 dex with respect to the control sample across all redshifts. This offset is primarily driven by infrared-selected AGN, where the mean sSFR is found to be elevated by as much as a factor of ∼5. The remaining population, comprised predominantly of X-ray AGN hosts, is found mostly consistent with inactive galaxies, exhibiting only a marginal elevation. We discuss scenarios that may explain these findings and postulate that AGN are less likely to be a dominant mechanism for moderating galaxy growth via quenching than has previously been suggested

ZFIRE: The Evolution of the Stellar Mass Tully-Fisher Relation to Redshift ~ 2.2

Large scale structure and cosmolog

The Size Evolution of Star-forming Galaxies since z ~ 7 Using ZFOURGE

Interstellar matter and star formationGalaxie

A SLUGGS and Gemini/GMOS combined study of the elliptical galaxy M60: wide-field photometry and kinematics of the globular cluster system

We present new wide-field photometry and spectroscopy of the globular clusters (GCs) around NGC 4649 (M60), the third brightest galaxy in the Virgo cluster. Imaging of NGC 4649 was assembled from a recently obtained Hubble Space Telescope/Advanced Camera for Surveys mosaic, and new Subaru/Suprime-Cam and archival Canada–France–Hawaii Telescope/MegaCam data. About 1200 sources were followed up spectroscopically using combined observations from three multi-object spectrographs: Keck/Deep Imaging Multi-Object Spectrograph, Gemini/Gemini Multi-Object Spectrograph and Multiple Mirror Telescope/Hectospec. We confirm 431 unique GCs belonging to NGC 4649, a factor of 3.5 larger than previous data sets and with a factor of 3 improvement in velocity precision. We confirm significant GC colour bimodality and find that the red GCs are more centrally concentrated, while the blue GCs are more spatially extended. We infer negative GC colour gradients in the innermost 20 kpc and flat gradients out to large radii. Rotation is detected along the galaxy major axis for all tracers: blue GCs, red GCs, galaxy stars and planetary nebulae. We compare the observed properties of NGC 4649 with galaxy formation models. We find that formation via a major merger between two gas-poor galaxies, followed by satellite accretion, can consistently reproduce the observations of NGC 4649 at different radii. We find no strong evidence to support an interaction between NGC 4649 and the neighbouring spiral galaxy NGC 4647. We identify interesting GC kinematic features in our data, such as counter-rotating subgroups and bumpy kinematic profiles, which encode more clues about the formation history of NGC 4649

Discovery of Extreme [O III]+Hβ Emitting Galaxies Tracing an Overdensity at z ~ 3.5 in CDF-South

Large scale structure and cosmolog

Effect of Local Environment and Stellar Mass on Galaxy Quenching and Morphology at 0.5 < z < 2.0

Large scale structure and cosmolog

First Detections of Compact AGN-triggered Radio Cores in RQ AGNs in the ECDFS

The mechanism triggering the radio emission in Radio-Quiet (RQ) Active Galactic Nuclei (AGN), found to be a relevant component of the faint radio population in deep fields, is hotly debated. Most RQ AGNs are unresolved or barely resolved at a few arcsec scale, comparable to the host galaxy size. RQ AGNs have also been found to share many properties with Star Forming Galaxies (SFG). They have similar radio luminosities and similar optical- /infrared-to-radio flux ratios. Their radio luminosity functions show similar evolutionary trends, and their host galaxies have similar colours, optical morphologies and stellar masses. For all these reasons it was concluded that the radio emission in such RQ AGNs is mainly triggered by star formation (SF). However in the local Universe (z<0.5) it is well known that both AGN and SF processes can contribute to the total radio emission in RQ AGNs (see e.g., Seyfert 2 galaxies), and there is growing evidence that composite SF/AGN systems are common at mid to high redshift (z>1-2). We used the Australian Long Baseline Array to observe a number of RQ AGNs in the Extended Chandra Deep Field South (ECDFS), and we detected compact, high-surface-brightness radio cores in some of them. Our pilot study shows that at least some of the sources classified as radio quiet contain an AGN that can contribute significantly (~50% or more) to the total radio emission. This is a first direct evidence of the presence of such AGN-triggered radio emission in RQ AGNs at cosmological redshifts

On the lack of correlation between [O III ]/[O II ] and Lyman continuum escape fraction

We present the first results of our pilot study of eight photometrically selected Lyman-continuum (LyC) emitting galaxy candidates from the COSMOS field and focus on their optical emission line ratios. Observations were performed in the H and K bands using the Multi-Object Spectrometer for Infra-Red Exploration (MOSFIRE) instrument at the Keck Observatory, targeting the [O ii], H β, and [Oiii] emission lines. We find that photometrically selected LyC emitting galaxy candidates have high ionization parameters, based on their high [O iii]/[O ii] ratios (O32), with an average ratio for our sample of 2.5 ± 0.2. Preliminary results of our companion Low-Resolution Imaging Spectrometer (LRIS) observations, targeting LyC and Ly α, show that those galaxies with the largest O32 are typically found to also be Ly α emitters. High O32 galaxies are also found to have tentative non-zero LyC escape fractions (f esc (LyC)) based on u band photometric detections. These results are consistent with samples of highly ionized galaxies, including confirmed LyC emitting galaxies from the literature. We also perform a detailed comparison between the observed emission line ratios and simulated line ratios from density bounded H ii regions modelled using the photoionization code MAPPINGS V. Estimates of f esc (LyC) for our sample fall in the range from 0.0 to 0.23 and suggest possible tension with published correlations between O32 and f esc (LyC), adding weight to dichotomy of arguments in the literature. We highlight the possible effects of clumpy geometry and mergers that may account for such tension.Fil: Bassett, R.. Swinburne University of Technology; Australia. Australian Research Council. Centre of Excellence for All Sky Astrophysics in 3 Dimensions; AustraliaFil: Ryan-Weber, E.V.. Swinburne University of Technology; Australia. Australian Research Council. Centre of Excellence for All Sky Astrophysics in 3 Dimensions; AustraliaFil: Cooke, J.. Swinburne University of Technology; AustraliaFil: Diaz, Carlos Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; Argentina. Gemini Observatory; ChileFil: Nanayakkara, T.. Leiden University; Países BajosFil: Yuan, T. T.. Swinburne University of Technology; Australia. Australian Research Council. Centre of Excellence for All Sky Astrophysics in 3 Dimensions; AustraliaFil: Spitler, L.R.. Australian Astronomical Observatories; Australia. Macquarie University; Australia. Macquarie University; AustraliaFil: Mestric, U.. Swinburne University of Technology; Australia. Australian Research Council. Centre of Excellence for All Sky Astrophysics in 3 Dimensions; AustraliaFil: Garel, T.. Centre de Recherche Astrophysique de Lyon; FranciaFil: Sawicki, Silvana Mabel. Saint Mary's University; CanadáFil: Gwyn, S.. National Research Council Canada; CanadáFil: Golob, A.. Saint Mary's University; Canad

ZFIRE: Galaxy Cluster Kinematics, H alpha Star Formation Rates, and Gas Phase Metallicities of XMM-LSS J02182-05102 at zcl = 1.6232

Interstellar matter and star formatio