A Wide-Field Study of the z~0.8 Cluster RX J0152.7-1357: the Role of Environment in the Formation of the Red-Sequence

[ABRIDGED] We present the first results from the largest spectroscopic survey to date of an intermediate redshift galaxy cluster, the z=0.834 cluster RX J0152.7-1357. We use the colors of galaxies, assembled from a D~12 Mpc region centered on the cluster, to investigate the properties of the red-sequence as a function of density and clustercentric radius. Our wide-field multi-slit survey with a low-dispersion prism in the IMACS spectrograph at Magellan allowed us to identify 475 new members of the cluster and its surrounding large scale structure with a redshift accuracy of dz/(1+z)~1% and a contamination rate of ~2% for galaxies with i<23.75 mag. We combine these new members with the 279 previously known spectroscopic members to give a total of 754 galaxies from which we obtain a mass-limited sample of 300 galaxies with stellar masses M>4x10^{10} M_sun. We find that the red galaxy fraction is 93+/-3% in the two merging cores of the cluster and declines to a level of 64+/-3% at projected clustercentric radii R>~3 Mpc. At these large projected distances, the correlation between clustercentric radius and local density is nonexistent. This allows an assessment of the influence of the local environment on galaxy evolution, as opposed to mechanisms that operate on cluster scales. Even beyond R>3 Mpc we find an increasing fraction of red galaxies with increasing local density. The red fraction at the highest local densities in two groups at R>3 Mpc matches the red fraction found in the two cores. Strikingly, galaxies at intermediate densities at R>3 Mpc, that are not group members, also show signs of an enhanced red fraction. Our results point to such intermediate density regions and the groups in the outskirts of the cluster, as sites where the local environment influences the transition of galaxies onto the red-sequence.Comment: 15 pages, 10 figures, 1 table, accepted for publication in ApJ, expanded introduction and additional references adde

Dynamic S0 Galaxies: a Case Study of NGC 5866

S0 galaxies are often thought to be passively evolved from spirals after star formation is quenched. To explore what is occurring in S0s, we present a multi-wavelength study of NGC5866--an isolated nearby edge-on S0. This study shows strong evidence for dynamic activities in the interstellar medium, which are most likely driven by supernova explosions in the galactic disk and bulge. We utilize Chandra, HST, and Spitzer data as well as ground-based observations to characterize the content, structure, and physical state of the medium and its interplay with stars in NGC5866. A cold gas disk is detected with an exponential scale height of 100pc. Numerous off-disk dusty spurs are clearly present: prominent ones can extend as far as 300pc from the galactic plane and are probably produced by individual SNe, whereas faint filaments can have ~ kpc scale and are likely produced by SNe collectively in disk/bulge. We also detect substantial amounts of diffuse Ha- and Pa-emitting gas with a comparable scale height as the cold gas. We find that the heating of the dust and warm ionized gas cannot be explained by the radiation from evolved stars alone, strongly indicating the presence of young stars in the disk at a low formation rate of ~ 0.05Msun/yr. We reveal the presence of diffuse X-ray-emitting hot gas, which extends as far as 3.5kpc from the disk and can be heated easily by Type Ia SNe in the bulge. However, the temperature of this gas is ~ 0.2keV, substantially lower than what might be expected from the mass-loss of evolved stars and Type Ia SNe heating alone, indicating mass loading from cool gas is important. The total masses of the cold, warm and hot gases are ~ 5*10^8, 10^4 and 3*10^7Msun. The relative richness of the gases, undergoing circulations between disk/halo, is perhaps a result of its relative isolation.Comment: 27 pages, 6 figures, 3 tables, ApJ in press, comments are welcom

The Star Formation Rate-Density Relation at 0.6<z<0.9 and the Role of Star Forming Galaxies

We study the star formation rates (SFRs) of galaxies as a function of local galaxy density at 0.6<z<0.9. We used a low-dispersion prism in IMACS on the 6.5-m Baade (Magellan I) telescope to obtain spectra and measured redshifts to a precision of sigma_z/(1+z)=1% for galaxies with z<23.3 AB mag. We utilized a stellar mass-limited sample of 977 galaxies above M>1.8x10^{10} Msun to conduct our main analysis. With three different SFR indicators, (1) Spitzer MIPS 24-micron imaging, (2) SED fitting, and (3) [OII]3727 emission, we find the median specific SFR (SSFR) and SFR to decline from the low-density field to the cores of groups and a rich cluster. For the SED and [OII] based SFRs, the decline in SSFR is roughly an order of magnitude while for the MIPS based SFRs, the decline is a factor of ~4. We find approximately the same magnitude of decline in SSFR even after removing the sample of galaxies near the cluster. Galaxies in groups and a cluster at these redshifts therefore have lower star formation (SF) activity than galaxies in the field, as is the case at z~0. We investigated whether the decline in SFR with increasing density is caused by a change in the proportion of quiescent and star forming galaxies (SFGs) or by a decline in the SFRs of SFGs. Using the rest-frame U-V and V-J colors to distinguish quiescent galaxies from SFGs we find the fraction of quiescent galaxies increases from ~32% to 79% from low to high density. In addition, we find the SSFRs of SFGs, selected based on U-V and V-J colors, to decline with increasing density by factors of ~5-6 for the SED and [OII] based SFRs. The MIPS based SSFRs for SFGs decline with a shallower slope. The order of magnitude decline in the SSFR-density relation at 0.6<z<0.9 is therefore driven by both a combination of declining SFRs of SFGs as well as a changing mix of SFGs and quiescent galaxies [ABRIDGED].Comment: 21 pages, 15 figures, 2 tables, resubmitted to ApJ after addressing referee comment

STAGES: the Space Telescope A901/2 Galaxy Evolution Survey

We present an overview of the Space Telescope A901/2 Galaxy Evolution Survey (STAGES). STAGES is a multiwavelength project designed to probe physical drivers of galaxy evolution across a wide range of environments and luminosity. A complex multi-cluster system at z~0.165 has been the subject of an 80-orbit F606W HST/ACS mosaic covering the full 0.5x0.5 (~5x5 Mpc^2) span of the supercluster. Extensive multiwavelength observations with XMM-Newton, GALEX, Spitzer, 2dF, GMRT, and the 17-band COMBO-17 photometric redshift survey complement the HST imaging. Our survey goals include simultaneously linking galaxy morphology with other observables such as age, star-formation rate, nuclear activity, and stellar mass. In addition, with the multiwavelength dataset and new high resolution mass maps from gravitational lensing, we are able to disentangle the large-scale structure of the system. By examining all aspects of environment we will be able to evaluate the relative importance of the dark matter halos, the local galaxy density, and the hot X-ray gas in driving galaxy transformation. This paper describes the HST imaging, data reduction, and creation of a master catalogue. We perform Sersic fitting on the HST images and conduct associated simulations to quantify completeness. In addition, we present the COMBO-17 photometric redshift catalogue and estimates of stellar masses and star-formation rates for this field. We define galaxy and cluster sample selection criteria which will be the basis for forthcoming science analyses, and present a compilation of notable objects in the field. Finally, we describe the further multiwavelength observations and announce public access to the data and catalogues.Comment: 29 pages, 22 figures; accepted to MNRAS. Full data release available at http://www.nottingham.ac.uk/astronomy/stage

Challenging homophobic bullying in schools: the politics of progress

In recent years homophobic bullying has received increased attention from NGOs, academics and government sources and concern about the issue crosses traditional moral and political divisions. This article examines this ‘progressive’ development and identifies the ‘conditions of possibility’ that have enabled the issue to become a harm that can be spoken of. In doing so it questions whether the readiness to speak about the issue represents the opposite to prohibitions on speech (such as the notorious Section 28) or whether it is based on more subtle forms of governance. It argues that homophobic bullying is heard through three key discourses (‘child abuse’, ‘the child victim’ and ‘the tragic gay’) and that, while enabling an acknowledgement of certain harms, they simultaneously silence other needs and experiences. It then moves to explore the aspirational and ‘liberatory’ political investments that underlie these seemingly ‘common-sense’ descriptive discourses and concludes with a critique of the quasi-criminal responses that the dominant political agenda of homophobic bullying gives rise to. The article draws on, and endeavours to develop a conversation between, critical engagements with the contemporary politics of both childhood and sexuality

A WISE View of Star Formation in Local Galaxy Clusters

We present results from a systematic study of star formation in local galaxy clusters using 22 micron data from the Wide-field Infrared Survey Explorer (WISE). The 69 systems in our sample are drawn from the Cluster Infall Regions Survey (CIRS), and all have robust mass determinations. The all-sky WISE data enables us to quantify the amount of star formation, as traced by 22 micron, as a function of radius well beyond R200, and investigate the dependence of total star formation rate upon cluster mass. We find that the fraction of star-forming galaxies increases with cluster radius but remains below the field value even at 3 R200. We also find that there is no strong correlation between the mass-normalized total specific star formation rate and cluster mass, indicating that the mass of the host cluster does not strongly influence the total star formation rate of cluster members.Comment: Accepted for publication in the Astrophysical Journal, 10 pages, 5 figure

The STAGES view of red spirals and dusty red galaxies: Mass-dependent quenching of star-formation in cluster infall

We investigate the properties of optically passive spirals and dusty red galaxies in the A901/2 cluster complex at redshift ~0.17 using restframe near-UV-optical SEDs, 24 micron IR data and HST morphologies from the STAGES dataset. The cluster sample is based on COMBO-17 redshifts with an rms precision of sigma_cz~2000 km/sec. We find that 'dusty red galaxies' and 'optically passive spirals' in A901/2 are largely the same phenomenon, and that they form stars at a substantial rate, which is only 4x lower than that in blue spirals at fixed mass. This star formation is more obscured than in blue galaxies and its optical signatures are weak. They appear predominantly in the stellar mass range of log M*/Msol=[10,11] where they constitute over half of the star-forming galaxies in the cluster; they are thus a vital ingredient for understanding the overall picture of star formation quenching in clusters. We find that the mean specific SFR of star-forming galaxies in the cluster is clearly lower than in the field, in contrast to the specific SFR properties of blue galaxies alone, which appear similar in cluster and field. Such a rich red spiral population is best explained if quenching is a slow process and morphological transformation is delayed even more. At log M*/Msol<10, such galaxies are rare, suggesting that their quenching is fast and accompanied by morphological change. We note, that edge-on spirals play a minor role; despite being dust-reddened they form only a small fraction of spirals independent of environment.Comment: Accepted for publication in MNRA

Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts

Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN

Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin