Astronomy and Particle Physics

Written evidence submitted by the Gemini UK National Time Allocation Committee (NTAC) (APP 27)

UK withdrawal from international ground-based facilities

I am a Reader in Cosmology in the School of Physics and Astronomy at the University of Birmingham, supported by a University Research Fellowship from the Royal Society (2005 – 2013). In the past decade I have used most of the 8-metre and 10-metre (8-m and 10-m) class optical/near-infrared telescopes on Earth to further my research. I therefore have a broad perspective on the use of large international ground-based observing facilities.

My co-signatories and I currently comprise the Gemini UK National Time Allocation Committee (NTAC) and therefore have the clearest scientific view of UK demand for observing time on the Gemini North and South (GN and GS) 8-m class telescopes. We are responsible for the twice-yearly peer review of proposals for observing time submitted by members of the UK community. As NTAC Chair I also represent the UK on the International Time Allocation Committee (ITAC) that is responsible for constructing the Gemini science program from the merged science rankings of the respective partners.

Our submission to the House of Commons Science and Technology Committee’s inquiry concentrates on the second item listed in the call for evidence:

"2. the impact of withdrawal from international ground-based facilities (for example the Gemini Observatory and Isaac Newton Group of telescopes) on the UK's research base and international reputation;"

Our view, as expressed in this submission (pages 2-4), may be summarized as follows:

· access to international northern 8-m class telescopes is essential to support the UK’s research base;

· the Gemini Observatory has matured into an efficient operation with high global impact;

· withdrawal from Gemini represents poor value for money on the UK’s investment to date;

· the most cost effective and scientifically productive way forward is to remain a member of the Gemini partnership post-2012.

Dr. Graham P. Smith (Chair of Gemini UK NTAC, 2010-2012)

Co-signatories (Members of Gemini UK NTAC): Dr. Nate Bastian (University of Exeter), Dr. Boris Gaensicke (University of Warwick), Dr. Duncan Farrah (University of Sussex), Dr. Rubina Kotak (Queens University of Belfast), Dr. Russell Smith (Durham University), Dr. Serena Viti (University College London)

16 February 2011


Access to international northern 8-m class telescopes is essential to support the UK’s research base

1.1 The global impact of UK astronomy is underwritten by access to multi-wavelength, multi-hemisphere observations from both space and ground. UK astronomers are currently leading key projects with truly global impact that are reliant on ground-based observations of faint objects first identified in space-based observations (see paragraphs A1 & A2). These space-based observations are intrinsically "all-sky". Global leadership therefore requires access to multi-hemisphere ground-based 8-m class telescopes.

1.2 The Gemini/Subaru Exchange Program is playing a key role in sustaining the global impact of the UK’s research base (see paragraph A3). This program allows UK astronomers to bid for observing time on Japan’s Subaru telescope through the Gemini UK NTAC. The key attraction for UK astronomers is Subaru’s wide-field capabilities that are unique among 8-metre class telescopes. This Gemini-enabled access to Subaru is of key strategic importance to UK astronomy, and demonstrates the flexible telescope access available to Gemini partners.

The Gemini Observatory has matured into an efficient operation with high global impact

2.1 In the last five years the number of peer-reviewed articles based on Gemini observations has roughly doubled, and the fraction of those lead by a UK astronomer has grown from approximately 10% to 20%. The impact of peer-reviewed articles based on Gemini observations is comparable, on average, with other 8-m class telescopes, i.e. Magellan, Subaru, and the European Southern Observatory’s (ESO’s) Very Large Telescopes (VLTs). In individual years the impact of Gemini publications can rival that of the 10-m Keck telescopes (see table in paragraph A4).

2.2 These statistics on the output from the Gemini Observatory confirm that, a decade after science observations began, Gemini has reached maturity as an international scientific facility. This has in part been enabled by the development and refinement of the observatory’s system of queue observing, whereby observatory staff perform the observations on behalf of the respective proposal teams when the sky conditions are optimally matched to those required by the science goals.

Withdrawal from Gemini represents poor value for money on the UK’s investment to date

3.1 The UK’s investment in Gemini to date has therefore helped to deliver a state of the art international research facility that offers astronomers the ability to observe in both Northern and Southern hemispheres. The teething problems of the first decade of operation are now resolved, and the coming decade promises great scientific rewards for members of the Gemini partnership. There is therefore a prima facie case that UK withdrawal from Gemini will waste the funds that the UK has invested in bringing the observatory to its current level of operational maturity and scientific productivity/impact.

3.2 UK demand for observing time on the Gemini telescopes is comparable with that for time on other 8-m class telescopes, including ESO’s VLTs. Moreover, UK demand surges when new instruments are commissioned – i.e. installed on the telescopes. We have seen this recently in UK NTAC meetings, with a crop of high quality proposals for observations with the new red-sensitive GMOS-N instrument in late 2010 and with GNIRS in 2011.

3.3 UK withdrawal from Gemini would further undermine value for money for the UK because several instruments in which the UK has invested are not yet available for use by the community. This investment in novel instruments – in particular FLAMINGOS-2 and MCAO – would therefore be wasted. It is also of great significance that ESO has no plans to make instruments comparable with FLAMINGOS-2 and MCAO available to the ESO community, of which the UK is part (see also paragraph A5).

The most cost effective and scientifically productive way forward is to remain a member of the Gemini partnership post-2012

4.1 Given the UK’s investment to date, and the current operational maturity and scientific impact of Gemini, it is clear that the most cost effective way to sustain the UK’s research base in relation to scientific exploitation of space-based discoveries is to remain a member of the Gemini partnership.

4.2 However in the current economic climate, a reduced partner share in the range 10–15% (the UK is currently a 24% partner) would help to reduce the burden on the public purse whilst providing sufficient telescope time for a top slice of world-class UK science to be supported. This assumes that we would have access to both GN and GS, and that the Gemini/Subaru exchange program would continue.

4.3 Gemini partners are also free to exchange time with other nations independently of the formal time exchange programs. For example, the same developments in ground-based astronomy in the southern hemisphere (e.g. SKA, LSST, ALMA) that motivate some to argue for concentrating UK optical/near-infrared observing resources on ESO will likely increase the enthusiasm of (for example) Japan to trade Subaru time in exchange for GS time. This would allow us to balance UK 8-metre observing time between the hemispheres, at a cost of £2–3million per year (assuming a 10–15% share of Gemini).

4.4 Replacing UK access to Gemini with (for example) access to the 10-m Gran Telescopio Canarias (GTC) on La Palma would set UK astronomy back a decade. This is because GTC is at a stage of development comparable with the Gemini telescopes a decade ago. Recovery from this setback would take many years, and woud require significant financial and intellectual investment from the UK in developing the operation of GTC and the suite of instruments available on GTC.

DECLARATION OF INTERESTS

All signatories to this evidence are regular users of 8-m class telescopes including all of Gemini, VLT, and Subaru.

Additional supporting information

A1 As a UK astronomer Professor Nial Tanvir’s access to the Gemini-North telescope in Hawaii was essential to his publication in Nature of the most distant known Gamma Ray Burst (http://adsabs.harvard.edu/abs/2009Natur.461.1254T).

A2 UK astronomers lead eight of the eighteen extragalactic/cosmology Key Programs on the Herschel Space Observatory, including the largest Key Program called "HerMES" (PI: Professor Seb Oliver). In 2011A follow-up ground-based observations of galaxies discovered with Herschel accounted for 10% of the total UK demand for Gemini observing time reviewed by the UK NTAC – i.e. a disproportionately large fraction of the total demand. This large fraction will likely increase in future semesters.

A3 Professor Chris Collins published important results on the evolution of the most massive galaxies in the universe in Nature, based on Subaru observations conducted thanks to the Gemini/Subaru Exchange Program (http://adsabs.harvard.edu/abs/2009Natur.458..603C). More generally, UK demand for observing time on Subaru has recently doubled – the average ranking of these proposals is in the 2nd quartile of all proposals that we receive – i.e. they are stronger than the average proposal.

A4 The impact of large ground-based telescopes is summarized in the following table. Impact is defined as the number of citations to articles that publish data from each observatory, normalized by the median number of citations earned by articles in the Astronomical Journal. On average over the last 5 years for which data are available, Gemini has been competitive with comparable 8-m class telescopes, i.e. VLT, Subaru, and Magellan. In individual years it has matched the performance of the pre-eminent Keck 10-m telescopes (i.e. 2006).

Telescope

2005

2006

2007

2008

2009

Average

Keck

3.3

3.5

4.2

4.2

4.0

3.8

Gemini

2.5

3.5

3.0

2.9

3.6

3.1

Magellan

2.6

2.4

4.2

2.9

3.6

3.1

Subaru

2.5

2.3

4.6

2.5

3.5

3.1

VLT

2.4

2.9

2.9

2.5

3.5

2.8

HST

2.0

2.4

3.9

2.8

2.8

2.8

Source: Compiled by Gemini Observatory, based on publication lists provided by the respective observatories.

A5 Gemini has a distinctive instrumentation strategy that will deliver technology on GS that ESO has no plans to deliver. Most notably, FLAMINGOS-2 will be the only near-infrared multi-object spectrograph in the southern hemisphere. For example, FLAMINGOS-2 and MOSFIRE on Keck will revolutionize studies of cosmic re-ionization at redshifts of 7<z<10. Participation in Gemini post-2012 would therefore promise world-leading positions for UK astronomers, for example, directly challenging colleagues in California who have direct access to the Keck telescopes in the northern hemisphere. MCAO will also shortly be a unique facility, because ESO has decided not to offer their Multi-conjugate AO Demonstrator (MAD) to the ESO community. MCAO will deliver near-infrared imaging at a spatial resolution and across fields of view comparable to the new WFC3 camera on the Hubble Space Telescope (HST). Naturally MCAO will not achieve the sensitivity of HST/WFC3, however this unique device will revolutionize ground-based near-infrared astronomy. The scientific potential of access to these instruments on GS is therefore huge and, most importantly, unique in the southern hemisphere.