19 research outputs found
Determination of the far-infrared properties of galaxies in the Coma cluster
This thesis presents results from the deepest ever far-infrared study of the Coma cluster (Abell 1656), with the Herschel PACS and SPIRE instruments being used to observe the cluster at a wavelength range of 70-500 _m. These observations resulted in a catalogue consisting of 70 galaxies which were spectroscopically confirmed as Coma cluster members, from which far-infrared galaxy luminosity functions at 70, 100 and 160 _m were constructed. Additionally, the far-infrared properties of 68 of these galaxies were determined from spectral energy distribution fits across the full wavelength range. Finally, these galaxies were grouped by morphological type, resulting in 30 elliptical galaxies, 37 spiral galaxies and one with an unknown morphology. These results were then compared to other studies of both clusters and the field in order to ascertain the extent to which environmental processes affect galaxy evolution. A comparison of the luminosity functions at 100 and 160 _m and the equivalent functions from the Herschel Virgo cluster survey Auld et al. (2013) showed similarities in both the functional form and the function parameters describing them. A further comparison of the Coma cluster luminosity functions at all three PACS wavelengths and various field galaxy luminosity functions was made, and again the forms and function parameters were consistent to within the errors. This would imply that the environmental processes thought to occur within the clusters do not have as great an effect on the galaxy population as initially thought. The far-infrared properties derived from the spectral energy distribution fits were analysed by galaxy type. The early-types were found to have mean normalised dust masses, dust temperatures and total infrared luminosities of log10 _
Mdust
Mstellar
A surprising consistency between the far-infrared galaxy luminosity functions of the field and Coma
We present new deep images of the Coma Cluster from the ESA Herschel Space Observatory at wavelengths of 70, 100 and 160 μm, covering an area of 1.75 × 1.0 square degrees
encompassing the core and south-west infall region. Our data display an excess of sources at flux densities above 100 mJy compared to blank-field surveys, as expected. We use extensive optical spectroscopy of this region to identify cluster members and hence produce cluster luminosity functions in all three photometric bands. We compare our results to the local field galaxy luminosity function, and the luminosity functions from the Herschel Virgo Cluster Survey. We find consistency between the shapes of the Coma and field galaxy luminosity functions at all three wavelengths; however, we do not find the same level of agreement with that of the Virgo Cluster
A surprising consistency between the far-infrared galaxy luminosity functions of the field and Coma
We present new deep images of the Coma Cluster from the ESA Herschel Space Observatory at wavelengths of 70, 100 and 160 mu m, covering an area of 1.75 x 1.0 square degrees encompassing the core and south-west infall region. Our data display an excess of sources at flux densities above 100 mJy compared to blank-field surveys, as expected. We use extensive optical spectroscopy of this region to identify cluster members and hence produce cluster luminosity functions in all three photometric bands. We compare our results to the local field galaxy luminosity function, and the luminosity functions from the Herschel Virgo Cluster Survey. We find consistency between the shapes of the Coma and field galaxy luminosity functions at all three wavelengths; however, we do not find the same level of agreement with that of the Virgo Cluster.</p
MEMRI study - feedback of MEMS dosing history improves adherence to long-term HAART: adherence is associated with incidence of ‘blips’ in viral load
In routine clinical care we investigated the effect on adherence to HAART of feedback to each patient of graphical plots highlighting recent errors in their dosing history, as compiled electronically using MEMS®. Patients established on HAART were randomised to receive either active feedback of recent dosing errors (Group A) at clinic visits, or to serve as controls (no feedback) (Group B). After 12 months the control group were un-blinded and given feedback for a further 6 months. Questionnaires were completed in the waiting room for adherence (GEEMA), Necessity/Concerns, Intrusiveness, Self-efficacy and Conscientiousness (baseline only). Those declining/excluded from using MEMS were invited to complete baseline questionnaires (Group C). Adherence was estimated from MEMS data as the average proportion of days with at least the prescribed number of doses taken between successive appointments. Drug Holidays (DH) were defined as 3 or more consecutive days without dosing. Of a cohort of 727 ~270 were approached. 180 were randomised. 147 had evaluable MEMS data (68 Group B: 79 Group A). 85 were in Group C (questionnaires only). Baseline characteristics were similar between Group A and B. Group C had a less common past history of AIDS. There was no significant difference in baseline conscientiousness between Groups A and B. Missed doses were much more likely at weekends than weekdays (OR=1.25; [1.15–1.35]). Those taking <95% of prescribed doses during the first interval between visits were defined as poor adherers, which included 69 patients (49%). Their average baseline adherence was 78%. In Group A, average adherence increased (p=0.001) to 90% after the first feedback session, while in Group B average adherence remained stable (p=0.405). In Group B, after un-blinding and start of feedback, adherence increased to 93%. Patients in Group B were significantly less likely to bring back their MEMS for reading at each appointment (p=0.031). The incidence of viral load ‘blips’ (>50 copies/ml) was significantly increased by DH (p=0.007), frequency of DH (p=0.016), length of DH (p=0.005), and missed doses during the 4 weeks before attendance (p=0.001). Feedback of electronically compiled dosing history data improves adherence to HAART treatment and appears to be an effective intervention for reducing the incidence of viral load ‘blips’. Further results including analysis of the questionnaires will be presented