David Alexander, Durham University
I am a professor of astronomy at Durham University, the Head of
Astronomy, and the Director of the Centre for Extragalactic Astronomy
(CEA). I obtained my PhD in 1999 at the University of Hertfordshire,
under the supervison of Prof James Hough, and I have been a
post-doctoral researcher at SISSA in Italy (1999-2000) and
Pennsylvania State University in the USA (2000-2003), working with
Prof Luigi Danese (on the ELAIS infrared survey) and Prof Niel Brandt
(on the Chandra Deep Field-North survey), respectively. I was awarded
an 8-year Royal Society University Research Fellowship in 2003, which
I initially held at Cambridge University in the UK (2003-2006) and
then transferred to Durham University (2006-2010). I won a Philip
Leverhulme Prize in 2008 and a Leverhulme Research Fellowship in
2012. I was made a Reader (associate professor) at Durham in April
2006 and I was promoted to Professor (full professor) in July 2011. In
June 2014 I was selected to the list of the most highly cited
researchers in space science for publications over the 2002-2012
period, a list that includes just ~100 astronomers world wide (~1% of
all professional astronomers); I was also selected to the list in
2015, 2016, 2017, 2018, and 2019. You can access the 2014 list here. Note that, on the basis of this list, Durham is
the joint
5th most successful institute in space sciences world wide and 1st in
Europe.
My research focuses on studying Active Galactic Nuclei (AGN; the sites of supermassive black hole [SMBH] growth) and their association with (and impact on) star formation through cosmic time. I primarily use X-ray, optical infrared, and submillimetre observations (typically the deepest ever taken) in conjunction with optical--infrared spectroscopy and integral field unit observations (IFU; spatially resolved spectroscopy). Much of my research is focused on the NuSTAR X-ray surveys and the Chandra Deep Field Surveys (CDFs; the deepest X-ray observations of the Universe ever taken) and the extensive multi-wavelength follow-up datasets that myself and others have obtained. These data provide a penetrating probe of AGN activity and SMBH growth in the distant Universe and I have used these observations to identify some of the most rapidly evolving (i.e., most quickly growing) objects in the Universe. These objects are often deeply enshrouded by dust and gas, making them difficult to detect, and I have developed techniques to identify these sources and determine their properties.
The image below provides a schematic overview of what I am investigating in my research, along with the key questions that I aim to address. In 2012 I wrote an extensive review on the current research in this area with Prof Ryan Hickox, a former research fellow in my group, which was inspired by an international workshop that we hosted at Durham in 2010; you can access the review here and you can see the talks and details of the workshop here. In 2015 I wrote a review article with Prof Niel Brandt, on the "Demographics, Physics, and Ecology of growing Supermassive Black Holes" from X-ray surveys, which is published in A&ARev; you can access the review here. In 2018 I wrote another review article with Ryan, this time on "Obscured AGN", which is published in ARA&A: you can access the review here.
I use leading observational facilities to explore the connections
between these components. In terms of identifying the sites of SMBH
growth, the major challenges are identifying the AGNs in the presence
of obscuration from dust and gas, and dilution of the AGN emission
from the host galaxy. Some major facilities that allow for significant
progress in this area are NuSTAR and Herschel. In terms of measuring
the star formation, the major challenges are in separating the
star-formation emission from that of any AGN activity, in the face of
significant obscuring material. The major new facilities that allow
for significant progress in this area are Herschel, SCUBA2, ALMA, and
JWST. AGNs are known to produce energetic outflows as the SMBH grows
and these outflows have the potential to shut down star formation in
the host galaxy by driving out the cold gas (from which stars
form). Major challenges in understanding the role that large-scale
outflows have on star formation are in unambiguously identifying
outflowing gas and estimating the kinetic energy of the gas in order
to determine the impact that it may have on star formation. The major
new facilities that allow for significant progress in this area are
IFU observations (spatially resolved spectroscopy), principal amongst
which is KMOS on the Very Large Telescope, which is a multi-IFU
instrument and allows for up-to 20 systems to be observed in one go
(when previously we could only observe one system at a time).
Publications:
I have published ~380 papers in peer-review journals since 1999,
which have been cited ~42,000 times. My current h-index is 106; i.e., I
have 106 papers with at least 106 citations each. For more details see
my list of papers in peer-reviewed
journals.
Research Group:
I have been very fortunate to be able to work with many talented
young researchers at Durham since 2006. Brief details on the people
who have been in my research group are given below. First those
currently in my group:
- Ms Carolina Andonie, PhD student (EU ITN BiD4BEST studentship), 2020+
- Mr Atharva Bagul, MRes student (self funded studentship), 2023+
- Ms Alice Eltvedt, PhD student (Team Durham/self funded studentship), 2020+
- Dr Claire Greenwell, PDRA (STFC consolidated grant), 2022+
- Mr Brivael Laloux, PhD student (EU ITN BiD4BEST studentship) based in Athens, 2020+
- Ms Ciera Sargant, PhD student (STFC studentship), 2023+
Below is a "photo" from one of our weekly group meetings in May
2020 taken using Zoom during the middle of the coronavirus
pandemic. With social-distance measures in force for much of 2020 this
is how we have learnt to interact! The name of each person is shown
but briefly with additional comments from top left: Jan Scholtz (now
PDRA at Chalmers), me, Victoria Fawcett (Durham PhD), Elisabeta Lusso
and Emanuele Nardini (now assistant professors in Firenze), Carolina
Andonie (starting Durham PhD from October 2020), Gabriele
Calistro-Rivera (ESO fellow in Munich: never based in Durham but
definitely has the Durham spirit!), Leah Morabito (Durham assistant
professor), Lizelke Klindt (Durham PhD), Zsofi Igo (Durham MPhys
research-project student), David Rosario (Durham PDRA), Alice Eltvedt
(Durham PhD), and Brivael LaLoux (starting Durham PhD from October
2020 but based in Athens) who was photo-shopped into the picture!
Below is a selfie photo of the group in February 2019 taken by
Lizelke Klindt. From left to right: Lizelke Klindt, Sotiria
Fotopoulou, Elisabeta Lusso, Jan Scholtz, Alice Eltvedt, David
Rosario, Jake Mitchell, Victoria Fawcett, and me; Alice and Jake are
regular post-graduate visitors to our group meetings.
Below is a selfie photo of the group in November 2017 taken by
David Rosario. From left to right: Thomas Jackson, me, Jan Scholtz,
Sotiria Fotopoulou, Lizelke Klindt, Elisabeta Lusso, and David
Rosario.
Below is a selfie photo of the group in October 2016 taken by
David Rosario. From left to right: Lizelke Klindt, Chris Harrison, Ady
Annuar, Jan Scholtz, me, and David Rosario.
Below is the list of PhD students and research fellows who have
been in my reseach group in the past. I still regularly publish papers
with most of them.
- Dr James Aird, research fellow (Durham Research Fellowship, 2012-2014); research fellow (University of Cambridge, 2014-2017); STFC Rutherford Fellowship (University of Leicester); NOW: Future Leaders Fellow/assistant Professor (University of Edinburgh)
- Dr Adlyka Annuar, PhD student (Malaysian Government, 2013-2017); NOW: assistant Professor/Lecturer (Universiti Kebangsaan, Malaysia)
- Dr Alice Danielson, PhD student (STFC studentship; Ogden Scientist in Schools, 2009-2014); STFC STEP research fellow (Durham, 2014-2015); NOW: Ogden Science Officer (University of Exeter)
- Dr Agnese Del Moro, research fellow (STFC consolidated grant, 2009-2015); research fellow (MPE, Garching, 2015-2019); NOW: industry (non academic)
- Dr Victoria Fawcett, PhD student (STFC studentship, 2018-2022); NOW: FLF research fellow (Newcastle University)
- Dr Sotiria Fotopoulou, research fellow (Swiss SNSF Fellowship, 2017-2019); NOW: Vice Chancellor fellow/assistant Professor (Bristol University)
- Dr Poshak Gandhi, research fellow (STFC Rutherford Fellowship, 2013-2014); NOW: Professor (University of Southampton)
- Dr Andy Goulding, PhD student (STFC studentship, 2008-2010); research fellow (CfA-Harvard, 2010-2014); NOW: staff position (Princeton University)
- Dr Chris Harrison, PhD student (STFC studentship, 2010-2014); research fellow (STFC STEP fellowship; STFC consolidated grant, 2014-2016); NOW: ESO Fellow (Garching)
- Prof Ryan Hickox, research fellow (STFC fellowship, 2009-2012); NOW: Professor (Dartmouth College)
- Dr Thomas Jackson, MSc by research student (self funded, 2017-2018); NOW: industy (academic) after receiving a PhD from Heidelberg
- Dr Lizelke Klindt, PhD student (Durham Doctoral Scholarship, 2016-2021); NOW: training to be a theologian after receiving her PhD
- Dr George Lansbury, PhD student (STFC studentship, 2012-2016); Herchel Smith fellow (University of Cambridge, 2016-2019); NOW: ESO fellow (Garching)
- Prof Bret Lehmer, research fellow (STFC fellowship, 2007-2009); Einstein fellow (JHU; NASA Goddard, 2009-2012); research fellow (JHU; NASA Goddard, 2012-2015); NOW: assistant Professor/Lecturer (University of Arkansas)
- Dr Elisabeta Lusso, research fellow (Durham Research Fellowship, 2017-2019); NOW: Arcetri Astrophysical Observatory (staff)
- Dr James Mullaney, research fellow (Philip Leverhulme Prize, 2008-2010); Eurotalents fellow (Saclay, Paris, 2010-2012); Leverhulme Early Career fellow (Durham, 2012-2013); Vice-Chancellor fellow (University of Sheffield, 2013-2016); NOW: assistant Professor/Lecturer (University of Sheffield)
- Mr Simon Murray, MSc by Research student (self funded), 2015-2016; NOW: industry (non academic)
- Dr David Rosario, research fellow (STFC consolidated grant), 2015-2021; NOW: senior lecturer (Newcastle University)
- Dr Manolis Rovilos, research fellow (Marie Curie Fellowship, 2012-2014); NOW: Patents Clerk (non academic)
- Dr Jan Scholtz, PhD student (STFC studentship+ESO studentship), 2015-2019; research fellow (Chalmers University, Sweden); NOW: research fellow (Kavli, Cambridge)
- Dr Flora Stanley, PhD student (Durham Doctoral Scholarship, 2012-2016); research fellow (Chalmers University, Sweden); NOW: research fellow (Paris)
For one marvellous week in August 2013 all but two of my former students and researchers (as of 2013) were at Durham. So we took a group photo, substituting in Chris Harrison and Bret Lehmer with stand ins (Nichloas Tejos and John Stott, respectively), who just by chance had the right-coloured shirts! Unfortunately, just by chance, I seemed to have put on my worst-ever combination of clothes - I had never intended to be in the photo!
Group photo, current and former members, in August 2013. From
left to right: George Lansbury, Agnese Del Moro, Poshak Gandhi, Chris
Harrison (stand in), Flora Stanley, Andy Goulding, Alice Danielson,
me, James Aird, James Mullaney, Bret Lehmer (stand in), Manolis
Rovilos, and Ryan Hickox.
This is the photo I prefer, not least because I am not in it, but
also because it is more natural and realistic - each person doing
their own thing (clear lack of direction!).
Workshops and conferences:
I have served on the organising committee for about 20 workshops
and conferences to date. While satisfying I have found that nothing
beats hosting your own scientific meeting. So since 2010 Ryan and myself
have organised an international workshop every 2 years based around
AGN activity and the impact of AGN on the growth of galaxies. We
alternate the workshop location between Durham University and
Dartmouth College.
Our first workshop in 2010 was originally planned
for April 2010 but an Iceland volcano erupted just before the start of
the workshop, shutting down European air space, and so we had to
postpone the workshop to August 2010. 2020 marked the tenth anniversary
of our fated first workshop and to celebrate our first decade we planned to host
a workshop in Iceland for September 2020 with a special one-day
excursion to face the volcano that disrupted our first
workshop. However, the coronavirus covid19 had other plans and we
had to postpone our workshop to April 2021... and then to September 2021...
and then finally, at last, we successfully hosted the meeting in
September 2022!
To be honest we wouldn't have wanted it any other way: our celebration
of the natural disaster that impacted on our first workshop was itself
disrupted by a global pandemic! Nature is always the boss. So in
Reykjavik we celebrated our first decade 12 years after our first
workshop... how poetic!
Our Durham-Dartmouth AGN workshop series (co-)organised with
Ryan:
Some other useful resources:
My Contact Details:
Prof. David Alexander, Head of Astronomy and the Director of the Center for Extragalactic Astronomy,
Center for Extragalactic Astronomy, Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK
Office: 119 Ogden Centre West; Phone: +44 191 3343594; Email: d.m.alexander (at) durham.ac.uk