Herschel ATLAS: The cosmic star formation history of quasar host galaxies

We present a derivation of the star formation rate per comoving volume of quasar host galaxies, derived from stacking analyses of far-infrared to mm-wave photometry of quasars with redshifts 0 I_(AB) > -32 We use the science demonstration observations of the first ~16 deg^2 from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) in which there are 240 quasars from the Sloan Digital Sky Survey (SDSS) and a further 171 from the 2dF-SDSS LRG and QSO (2SLAQ) survey. We supplement this data with a compilation of data from IRAS, ISO, Spitzer, SCUBA and MAMBO. H-ATLAS alone statistically detects the quasars in its survey area at >5σ at 250,350 and 500 μm. From the compilation as a whole we find striking evidence of downsizing in quasar host galaxy formation: low-luminosity quasars with absolute magnitudes in the range -22 > I_(AB) > -24 have a comoving star formation rate (derived from 100 μm rest-frame luminosities) peaking between redshifts of 1 and 2, while high-luminosity quasars with I_(AB) I_(AB) > -24 quasars evolves as (1 + z)^(2.3±0.7) at z I_(AB) > -28. We tentatively interpret this as a combination of a declining major merger rate with time and gas consumption reducing fuel for both black hole accretion and star formation

From respect to reburial: negotiating pagan interest in prehistoric human remains in Britain, through the Avebury consultation

The recent Avebury Consultation on reburial has drawn considerable public and professional attention to the issue of pagan calls for respect towards the care of human remains. Our work has pointed to the importance of archaeologists and others engaging seriously and respectfully with pagans as significant stakeholders in our heritage. The Avebury Reburial Consultation suggests this dialogue is increasing in strength, but we identify problems in the process. We focus here on approaches to the prehistoric dead and worldviews enabling communication from which calls or ‘claims’ for the reburial of prehistoric pagan human remains, versus their retention for scientific study, are articulated; frameworks for assessing and adjudicating such ‘claims’; and implications for the interest groups concerned. We argue that room must be made for philosophical debate and the emotional and spiritual views of pagans, in order to improve dialogue, develop common ground, and enable participatory decision-making and situational pragmatism

Detecting gravitational lensing cosmic shear from samples of several galaxies using two-dimensional spectral imaging

Studies of weak gravitational lensing by large-scale structures require the measurement of the distortions introduced to the shapes of distant galaxies at the few percent level by anisotropic light deflection along the line of sight. To detect this signal on 1-10 arcmin scales in a particular field, accurate measurements of the correlations between the shapes of order 1000-10000 galaxies are required. This large-scale averaging is required to accommodate the unknown intrinsic shapes of the background galaxies, even with careful removal of systematic effects. Here an alternative is discussed. If it is possible to measure accurately the detailed dynamical structure of the background galaxies, in particular rotating disks, then it should be possible to measure directly the cosmic shear distortion, as it generally leads to a non-self-consistent rotation curve. Narrow spectral lines and excellent two-dimensional spatial resolution are required. The ideal lines and telescope are CO rotational transitions and the Atacama Large Millimeter Array (ALMA) respectively.Comment: 12 pages, 4 figures, Expected to appear in ApJ Letters Vol. 570, 10 May 2002. Replaced with final proof version correcting minor typo

The very bright SCUBA galaxy count: looking for SCUBA galaxies with the Mexican Hat Wavelet

We present the results of a search for bright high-redshift galaxies in two large SCUBA scan-maps of Galactic regions. A Mexican Hat Wavelet technique was used to locate point sources in these maps, which suffer high foreground contamination as well as typical scan-map noise signatures. A catalogue of point source objects was selected and observed again in the submillimetre continuum, and in HCO+ (3->2) at zero redshift to rule out Galactic sources. No extragalactic sources were found. Simulations show that the survey was sensitive to sources with fluxes > 50 mJy, depending on the local background. These simulations result in upper limits on the 850-micron counts of SCUBA galaxies of 53 per square degree at 50 mJy and 2.9 per square degree at 100 mJy.Comment: Accepted by MNRA

Phosphorylation of MCPH1 isoforms during mitosis followed by isoform‐specific degradation by APC/C‐CDH1

Microcephalin‐1 (MCPH1) exists as 2 isoforms that regulate cyclin‐dependent kinase‐1 activation and chromosome condensation during mitosis, with MCPH1 mutations causing primary microcephaly. MCPH1 is also a tumor suppressor protein, with roles in DNA damage repair/checkpoints. Despite these important roles, there is little information on the cellular regulation of MCPH1. We show that both MCPH1 isoforms are phosphorylated in a cyclin‐dependent kinase‐1–dependent manner in mitosis and identify several novel phosphorylation sites. Upon mitotic exit, MCPH1 isoforms were degraded by the anaphase‐promoting complex/cyclosome–CDH1 E3 ligase complex. Anaphase‐promoting complex/cyclosome–CDH1 target proteins generally have D‐Box or KEN‐Box degron sequences. We found that MCPH1 isoforms are degraded independently, with the long isoform degradation being D‐Box dependent, whereas the short isoform was KEN‐Box dependent. Our research identifies several novel mechanisms regulating MCPH1 and also highlights important issues with several commercial MCPH1 antibodies, with potential relevance to previously published data.—Meyer, S. K., Dunn, M., Vidler, D. S., Porter, A., Blain, P. G., Jowsey, P. A. Phosphorylation of MCPH1 isoforms during mitosis followed by isoform‐specific degradation by APC/C‐CDH1. FASEB J. 33, 2796–2808 (2019). www.fasebj.or

Repurposing the (super)crip: media representations of disability at the Rio 2016 Paralympic Games

Mega-events attract ever larger media audiences, and the 2016 Rio Paralympics were no exception. As audiences grow, media coverage extends to ever more varied domains, which are themselves then colonised by an increasing range of discourses. One of main discourses to develop since the early 2000s has been that of the so-called “supercrip”, one which challenges the notion of “impairment” often connected with disability by foregrounding the para-athletes’ triumph over adversity, celebrating instead their courage, grit and perseverance leading to athletic success and personal and increasingly national prestige. In this article we analyse the continuing importance of the supercrip discourse in coverage of the Rio Paralympics, but also move on to highlight its tactical alignment with other – both competing and complementary – discourses of nationalism, sexualisation, militarisation and celebritisation. We analyse textual and visual manifestations of these discourses using both Critical Discourse Analysis and Foucauldian discourse analysis. We conclude by paying particular attention to the increasing visibility of discourses which, while acknowledging the potentially positive role of the supercrip discourse in focussing on athletic success, repurpose that discourse by foregrounding instead the day-to-day experiences of belittling misrepresentation and neglect, including political neglect

Small Deviations from Gaussianity and The Galaxy Cluster Abundance Evolution

We raise the hypothesis that the density fluctuations field which originates the growth of large scale structures is a combination of two or more distributions. By applying the statistical analysis of finite mixture distributions to a specific combination of Gaussian plus non-Gaussian random fields, we studied the case where just a small departure from Gaussianity is allowed. Our results suggest that even a very small level of non-Gaussianity may introduce significant changes in the cluster abundance evolution rate.Comment: 10 pages with 2 figures, accepted for publication in Ap

Fact: Many SCUBA galaxies harbour AGNs

Deep SCUBA surveys have uncovered a large population of ultra-luminous galaxies at z>1. These sources are often assumed to be starburst galaxies, but there is growing evidence that a substantial fraction host an AGN (i.e., an accreting super-massive black hole). We present here possibly the strongest evidence for this viewpoint to date: the combination of ultra-deep X-ray observations (the 2 Ms Chandra Deep Field-North) and deep optical spectroscopic data. We argue that upward of 38% of bright (f850um>=5mJy) SCUBA galaxies host an AGN, a fraction of which are obscured QSOs (i.e., L_X>3x10^{44} erg/s). However, using evidence from a variety of analyses, we argue that in almost all cases the AGNs are not bolometrically important (i.e., <20%). Thus, star formation appears to dominate their bolometric output. A substantial fraction of bright SCUBA galaxies show evidence for binary AGN activity. Since these systems appear to be interacting and merging at optical/near-IR wavelengths, their super-massive black holes will eventually coalesce.Comment: Invited contribution - 10 pages, 4 figures, to appear in the Proceedings of the ESO/USM/MPE Workshop on "Multiwavelength Mapping of Galaxy Formation and Evolution", eds. R. Bender and A. Renzin

The Scatter in the Relationship between Redshift and the Radio-to-Submm Spectral Index

We derive the scatter in the relationship between redshift and radio-to-submm spectral index, alpha^{350}_{1.4}, using the observed spectral energy distributions of 17 low redshift star forming galaxies. A mean galaxy model is derived, along with the rms scatter in alpha^{350}_{1.4}. The scatter is roughly constant with redshift. Constant rms scatter, combined with the flattening of the mean alpha^{350}_{1.4} -- z relationship with increasing redshift, leads to increasing uncertainty for redshift estimates at high redshifts. Normalizing by the dust temperature in the manner proposed by Blain decreases the scatter in alpha^{350}_{1.4} for most of the sample, but does not remove outliers, and free-free absorption at rest frequencies above 1.4 GHz is not likely to be a dominant cause for scatter in the alpha^{350}_{1.4} -- z relationship. We re-derive the cumulative redshift distribution of the 14 field galaxies in a recent submm and radio source sample of Smail et al.. The most likely median redshift for the distribution is 2.7, with a conservative lower limit of z = 2, as was also found by Smail et al. based on the original alpha^{350}_{1.4} -- z models. The normalization and shape of the redshift distribution for the faint submm sources are consistent with those expected for forming elliptical galaxies.Comment: Added Erratum, standard AAS LATEX forma