The Herschel Extragalactic Legacy Project (HELP) is a European research initiative to capitalise on the vast imaging data that was collected by the Herschel space telescope. The figure below shows the 23 fields that comprise HELP overlaid on the Planck map of galactic dust. These are mainly the famous extragalactic fields and come in different sizes and depths.
Last week we had a conference here at Sussex to show the astronomy community the data we are about to release, discuss the methods used to create it and talk about the science results from Herschel and HELP, past, present and future.
I gave a talk on the HELP masterlist the slides for which are available below.
We have a great deal of work to do to finish running the whole data pipeline for all 23 fields, containing photometry, photmetric redshifts, a full analysis of the Herschel fluxes and fitted galaxy spectral energy distributions for all the Herschel objects. It will all be worth it when we start to see the science results come through from this very wide area data release covering around 1300 square degrees.
I spent last week at the Institute of Astronomy in Cambridge discussing how the UK can take advantage of the incredible imaging data that promises to be produced by the Large Synoptic Survey Telescope. The telescope is set to receive first light in 2019 and there is a vast amount of work to do to prepare for the deluge of data that is about to flow out of Chile. One of the challenges is making sure we make best use of UK expertise and work in close collaboration with the majority of LSST scientists in the US.
We were meeting to discuss how best to target UK research to complement work being done elsewhere. There are some definite niches available to us, partly because of access we have to some UK data and partly for the expertise in multiwavelength science that has been built up here.
There were a number of excellent talks about Active Galactic Nuclei (AGN) and galaxy formation based on studies right across the wavelengths (x-rays to radio waves). There were a number of talks about photometric redshifts which is of direct relevance to the Herschel Extragalactic Legacy Project (HELP) that we are currently working on in Sussex. Ultimately it seems that building some software within the LSST stack that can handle UK near infrared images may be the best first step to preparing for possible multiwavelength LSST science.
We have around two years to prepare for the first LSST images and it is vital that we work to have software in place ready for it. On a personal note I think developing any code for multiwavelength pixel-based image analysis within the LSST software stack is an opportunity for us early career scientists to build expertise that will make us employable over the lifetime of LSST.
On a completely separate note; being back in Cambridge was a great chance to have a look around the West Cambridge site which has changed drastically since I was an undergraduate at the Cavendish. I visited the Department of Chemical Engineering and Biotechnology which was extremely impressive. There has clearly been a massive investment in the various science departments that have been built/extended there. I look forward to seeing how it continues to develop and all the research that will be generated there by what is essentially a load of geeks in a field.
I wasn’t very familiar with the MeerKAT International Giga-Hertz Tiered Extragalactic Exploration (MIGHTEE) survey or even the Karoo Array Telescope (MeerKAT)* which is a precursor to the enormously ambitious Square Kilometre Array (SKA). Gotta Love Physics Acronyms (GLPA). It reminded me what an exciting time to be doing astronomy it is with some huge data sets on the way at unprecedented scales. It was a chance to think about how to tie together the quite disparate data from various wavelength regimes which fed in quite well to the LSST meeting the following week.
A lot of the fields overlap with the LSST deep drilling fields as well as the Herschel extragalactic fields. The four fields are XMM-LSS, COSMOS, ELAIS-S1 and CDFS (names of areas on the sky that have been previously imaged)**. The challenge will be to move beyond the catalogue based cross matching done so far and towards dealing directly with pixel data.
I did my masters project on the SKA back in 2006 and it is amazing to see it starting to take shape with actual radio dishes on the ground in South Africa.
Being in Oxford was also a useful opportunity to meet with other members of the Herschel Extragalactic Legacy Project (HELP) to talk about the last stages of the project and how we are going to deliver all the final data. Something we can talk about further at the HELP meeting in Sussex in October.
* I can’t find where the Meer in MeerKAT comes from. I think there are actual meerkat populations near the telescope but this might be a prime example of acronym nesting.
** XMM-LSS: X-ray Multi Mirror telescope Large Scale Structure survey
COSMOS: Cosmological Evolution Survey***
ELAIS-S1: South 1
CDFS: Chandra Deep Field South
A couple of weeks ago I was in Boston for a meeting of the SERVS team and I thought I should get round to blogging about it. The small conference was organised by Anna Sajina at Tufts and was concerned with determining priorities for presenting and analysing data from the Spitzer telescope. I was there because a large part of my work is concerned with building a multiwavelength catalogue for the Herschel Extragalactic Legacy Project (HELP) and we are ingesting a number of Spitzer surveys including SERVS.
SERVS data is a key part of the HELP pipeline because we typically use the Infrared Array Camera (IRAC) fluxes to select objects to define our samples. It was also a chance to hear about all the research being done with these Spitzer fluxes which cover the mid infrared part fo the spectrum.
I have spent the last two days in Hull for the National Astronomy Meeting (NAM). I have seen a number of excellent talks already. In particular, the session on low surface brightness galaxies yesterday was fascinating and had a number of gems in it. David Valls-Gabaud gave a great overview of the field. It was particularly interesting to me because I realised the problem I work on (deblending) will be increasingly important as we move into the era of deeper and deeper surveys. As our telescopes become more sensitive we can observe fainter and fainter objects and the sky becomes more full of things. This means they are more likely to overlap and the problem of determining where light comes from becomes harder and harder. It was good to remind myself of the final aim of my work.
The day finished with a fantastic public talk by Chris Lintott. It was pitched at a perfect level for the public, but I also think a lot of us early stage career scientists and PhD students found it refreshing. Sometimes, particularly in fields you don’t directly work on, you learn a lot more by starting at the beginning. Perhaps unsurprisingly, some of the questions by 5-10 year olds were very probing and highlighted the vast amount there is still to learn. They have more courage to admit that they don’t know something!