We investigate the relation between star formation rates (
$\dot{{M}}_s$
) and AGN properties in optically selected type 1 quasars at 2 < z < 3 using data from Herschel and the SDSS. We find that
...$\dot{{M}}_s$
remains approximately constant with redshift, at 300 ± 100 M⊙ yr−1. Conversely,
$\dot{{M}}_s$
increases with AGN luminosity, up to a maximum of ∼ 600 M⊙ yr−1, and with C iv FWHM. In context with previous results, this is consistent with a relation between
$\dot{{M}}_s$
and black hole accretion rate (
$\dot{{M}}_{{\rm bh}}$
) existing in only parts of the
$z-\dot{{M}}_{s}-\dot{{M}}_{{\rm bh}}$
plane, dependent on the free gas fraction, the trigger for activity, and the processes that may quench star formation. The relations between
$\dot{{M}}_s$
and both AGN luminosity and C iv FWHM are consistent with star formation rates in quasars scaling with black hole mass, though we cannot rule out a separate relation with black hole accretion rate. Star formation rates are observed to decline with increasing C iv equivalent width. This decline can be partially explained via the Baldwin effect, but may have an additional contribution from one or more of three factors; M
i
is not a linear tracer of L
2500, the Baldwin effect changes form at high AGN luminosities, and high C iv EW values signpost a change in the relation between
$\dot{{M}}_s$
and
$\dot{{M}}_{{\rm bh}}$
. Finally, there is no strong relation between
$\dot{{M}}_s$
and Eddington ratio, or the asymmetry of the C iv line. The former suggests that star formation rates do not scale with how efficiently the black hole is accreting, while the latter is consistent with C iv asymmetries arising from orientation effects.
The first complete sub-millimeter spectrum of the Seyfert 2 galaxy NGC 1068 has been observed with the SPIRE Fourier transform spectrometer on board the Herschel Space Observatory. The sequence of CO ...lines, lines from Hsub 2O, the fundamental rotational transition of hydrogen fluoride, two o-Hsub 2Osup + lines, and one line each from CHsup + and OHsup + have been detected, together with the two CI lines and the NII 205 mum line. The observations in both single pointing mode with sparse image sampling and in mapping mode with full image sampling allow us to disentangle two molecular emission components, one due to the compact circumnuclear disk (CND) and one from the extended region encompassing the star-forming ring (SF-ring). The emission of Hsub 2Osup + and OHsup + are in agreement with PDR models with cosmic-ray ionization. The diffuse ionized atomic component observed through the NII 205 mum line is consistent with previous photo-ionization models of the star-burst.
A POPULATION OF DUST-RICH QUASARS AT z ∼ 1.5 SOPHIA DAI, Y; BERGERON, Jacqueline; MAGDIS, Georgios E ...
The Astrophysical journal,
07/2012, Volume:
753, Issue:
1
Journal Article
Peer reviewed
We report Herschel SPIRE (250, 350, and 500 mu m) detections of 32 quasars with redshifts 0.5 < or =, slant z < 3.6 from the Herschel Multi-tiered Extragalactic Survey (HerMES). These sources are ...from a MIPS 24 mu m flux-limited sample of 326 quasars in the Lockman Hole Field. The extensive multi-wavelength data available in the field permit construction of the rest-frame spectral energy distributions (SEDs) from ultraviolet to the mid-infrared for all sources, and to the far-infrared (FIR) for the 32 objects. Most quasars with Herschel FIR detections show dust temperatures in the range of 25-60 K, with a mean of 34 K. The FIR luminosities range from 10 super(11.3) to 10 super(13.5) L sub(middot in circle), qualifying most of their hosts as ultra- or hyper-luminous infrared galaxies. These FIR-detected quasars may represent a dust-rich population, but with lower redshifts and fainter luminosities than quasars observed at ~1 mm. However, their FIR properties cannot be predicted from shorter wavelengths (0.3-20 mu m, rest frame), and the bolometric luminosities derived using the 5100 Angstrom index may be underestimated for these FIR-detected quasars. Regardless of redshift, we observed a decline in the relative strength of FIR luminosities for quasars with higher near-infrared luminosities.
In these proceedings, we summarise the exploration so far of the relationship between the afterglow luminosity (measured at rest frame 200s; log L 200 s ) and average afterglow decay rate (measured ...from rest frame 200s onwards, α > 200 s ) of long duration Gamma-ray Bursts (GRBs), first reported in the optical/UV light curves of GRB afterglows. We show that this correlation is also present in the X-ray afterglows of GRBs as observed by Swift-XRT. We explore how the parameters of the correlation observed in both the X-ray and optical/UV light curves relate to each other and the prompt emission phase and whether these correlations are consistent with predictions of the standard afterglow model. We find that the observed correlations are consistent with a common underlying physical mechanism producing GRBs and their afterglows regardless of the detailed temporal behaviour. However, a basic afterglow model has difficulty explaining all the observed correlations. This leads us to briefly discuss alternative more complex models.
This article describes the development of a low secure service in Gloucester, England. It uses the structure of the service user journey to analyse practice and innovations which have been ...implemented within the service. The article refers to evidence and discusses the implications of the changing market place within which low secure services are positioned.
At present, the precision of deep ultraviolet photometry is somewhat limited by the dearth of faint ultraviolet standard stars. In an effort to improve this situation, we present a uniform catalog of ...11 new faint (u ~ 17) ultraviolet standard stars. High-precision photometry of these stars has been taken from the Sloan Digital Sky Survey and Galaxy Evolution Explorer archives and combined with new data from the Swift Ultraviolet Optical Telescope to provide precise photometric measures extending from the near-infrared to the far-ultraviolet. These stars were chosen because they are known to be hot (2,000 < T eff < 5,000 K) DA white dwarfs with published Sloan spectra that should be photometrically stable. This careful selection allows us to compare the combined photometry and Sloan spectroscopy to models of pure hydrogen atmospheres to both constrain the underlying properties of the white dwarfs and test the ability of white dwarf models to predict the photometric measures. We find that the photometry provides good constraints on white dwarf temperatures, which demonstrates the ability of Swift/UVOT to investigate the properties of hot luminous stars. We further find that the models reproduce the photometric measures in all 11 passbands to within their systematic uncertainties. Within the limits of our photometry, we find the standard stars to be photometrically stable. This success indicates that the models can be used to calibrate additional filters to our standard system, permitting easier comparison of photometry from heterogeneous sources. The largest source of uncertainty in the model fitting is the uncertainty in the foreground reddening curve, a problem that is especially acute in the UV.
This article discusses the methodology used to engage a group of patients in a low secure unit in a research project to evaluate the effects of methods of observation. The results are summarised, and ...some surprising themes from the interviews are reflected upon. This very small scale, qualitative study suggests that patients in secure units can be meaningfully engaged in research; and this must continue, as this project has demonstrated that these patients have views which other published research has not brought to light.
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