Seminars
3rd Term 2011/2012
Seminars commence at 4pm (unless otherwise stated) in Pearson Lecture Theatre. Coffee is provided at 3.30pm in G08, Kathleen Lonsdale Building. The seminar organisers are Mikako Matsuura (mikako AT star.ucl.ac.uk), Caitriona Jackman (caitriona.jackman AT ucl.ac.uk) and Filipe Abdalla (fba AT star.ucl.ac.uk)
| Date |
Title of seminar |
Speaker name and institution |
| Monday, 23 April 2012 |
Steven Fossey - "ExoCafe: java and hot Jupiters and undergraduate research in astrophysics" |
Steven Fossey, Peter Thomas (ULO/UCL) and Thomas Greve (UCL) |
| Monday, 30 April 2012 | The Transient Universe: Cosmic Explosions and Dark Energy | Mark Sullivan (Oxford) |
| Monday, 14 May 2012 | The Search for Gravitational Waves |
Mike Cruise (Birmingham) |
| Monday, 21 May 2012 | Matt - "Solar cycle 24: where are we and where are we going?" |
Mike Lockwood/Matt Owens (Reading) |
| Monday, 28 May 2012 | Cosmology with galaxy shapes |
Benjamin Joachimi (Edinburgh) |
Abstracts
"ExoCafe: java and hot Jupiters and undergraduate research in astrophysics" Steven Fossey (ULO/UCL)
"The Development of UCL's Observatory" Peter Thomas (ULO/UCL)
"The nature of extremely bright millimeter sources discovered by the South Pole Telescope" Thomas Greve (UCL)
Large-scale extragalactic surveys at millimeter and sub-millimeter wavelengths carried out by the 10m South Pole Telescope (SPT) and the Herschel Space Observatory in 2007-2009 discovered a hitherto unknown population of extremely bright sources - more than 10x brighter than the sub-millimeter galaxies (SMGs) uncovered by SCUBA (from much smaller fields) over a decade ago. Although rare on the sky (~0.1 per sq. degree) they are far more common than a simple extrapolation of the SCUBA number counts would suggest.
We have undertaken a comprehensive multi-wavelength follow-up campaign of these ultra-bright SMGs with the aim of unveiling their nature, basic physical properties and redshift distribution. We confirm the theoretical expectations that they are typical SMGs (same luminosities, masses etc) being strongly lensed (magnification factors >>10) - mostly by a single massive galaxy, but in a few cases by a cluster of galaxies. Their redshift distribution - derived form optical/UV and CO line spectroscopic, as well as photometric redshifts - reveal that they are at systematically higher redshifts than the unlensed SCUBA sources. Although, this is in part attributable to selection effects, it suggests that the much sought after progenitors of the red/dead massive galaxies seen at z~2 are to be found within our SPT sample. This new population of sources are formidable ALMA targets owing to their high magnification, which allows for extremely sensitive (line) probes of their star forming gas on intrinsically very small scales (<<1kpc).'
"The Transient Universe: Cosmic Explosions and Dark Energy" Mark Sullivan (Oxford)
Type Ia Supernovae (SNe Ia) provide our most mature probe of dark energy. I will present the latest dark energy constraints from the Supernova Legacy Survey, including new astrophysical effects in the SN Ia population that are refining their use as cosmological probes. I will then show recent results from the next generation of local transient surveys, including details of new constraints on SN Ia progenitors.
"The Search for Gravitational Waves" Mike Cruise (Birmingham)
Most of the information we have about the Universe has so far been obtained using electromagnetic radiation- essentially giving us a map of the distribution of warm and hot matter around us. Following Einstein’s prediction that there would be dynamic modes in the gravitational field of massive objects, scientists have been searching for evidence of gravitational waves as a new tool to study the cosmos. If detected, gravitational waves will give us a picture of the Universe in terms of the motion of highly relativistic masses- Black Holes and Neutron Stars. The detectors are some of the largest and most sensitive apparatus ever built and results in the next few years promise detections which will lead towards new understanding of Black Hole formation, galaxy mergers and of gravity itself.
"Solar cycle 24: where are we and where are we going?" Matt Owens (Reading)
March 2012 brought the first solar and geomagnetic disturbances of any note during solar cycle 24. But perhaps what was most remarkable about these events was how unremarkable they were in magnitude compared to others during the space-age, only attracting attention because solar activity had been so quiet. Because it follows an exceptionally low and long-lived solar cycle minimum, this cycle is likely to extend a long-term decline in solar activity that started around 1985 and that could even lead to conditions similar to the Maunder minimum within 40 years from now, with implications for solar-terrestrial science and the mitigation of space weather hazards and maybe even for climate in certain regions and seasons.
"Cosmology with galaxy shapes" Benjamin Joachimi (Edinburgh)
The images of distant galaxies are distorted by the gravitational lensing of the intervening large-scale structure of the Universe. The resulting correlations between galaxy shapes are one of the most powerful probes of dark matter, dark energy, and gravity. However, tidal gravitational fields can physically align galaxies and thereby mimic the lensing effect. Hence a thorough understanding of these intrinsic galaxy alignments is crucial for precision cosmology, and in addition can yield unique insights into galaxy formation and evolution. I am going to present recent observational results as well as progress in the modelling of the intrinsic shapes of galaxies and their properties.
Page last modified on 22 may 12 11:24 by Kajal H Nakum
