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); you can access the 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 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 we 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 download the review here and you can see the talks and details of the workshop here. I have just finished a new review article with Prof Niel Brandt, on the "Demographics, Physics, and Ecology of growing Supermassive Black Holes" from X-ray surveys, which has just been accepted to A&ARev; you can download 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. The new 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, and ALMA. 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).

I am leading research in all of these areas using the above mentioned facilities. Below I provide links to some of the key facilities and surveys.

NuSTAR Extragalactic Surveys
GOODS Herschel and CANDELS Herschel Surveys
LABOCA ECDFS Submm Survey (LESS)
SCUBA2 Cosmology Legacy Survey (S2CLS)
Chandra Deep Protocluster Survey (SSA22)
Chandra Deep Field-North (CDF-N) survey
Chandra Deep Field-South (CDF-S) survey
Extended Chandra Deep Field-South (E-CDF-S) survey

Publications:

I have published >280 papers in peer-review journals since 1999, which have been cited >23,000 times. My current h-index is 81; i.e., I have 81 papers with at least 81 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 Adlyka Annuar, PhD student (Malaysian Government), 2013+
  • Dr Sotiria Fotopoulou, research fellow (Swiss SNSF Fellowship), 2017+
  • Ms Lizelke Klindt, PhD student (Durham Doctoral Scholarship), 2016+
  • Dr Elisabetta Lusso, research fellow (Durham Research Fellowship), 2017+
  • Dr David Rosario, research fellow (STFC rolling grant), 2015+
  • Mr Jan Scholtz, PhD student (STFC studentship), 2015+

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 them.

  • Dr James Aird, research fellow (Durham Research Fellowship, 2012-2014); NOW: research fellow (University of Cambridge)
  • 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 rolling grant, 2009-2015); NOW: research fellow (MPE, Munich)
  • Dr Poshak Gandhi, research fellow (STFC Rutherford Fellowship, 2013-2014); NOW: associate Professor/Reader (University of Southampton)
  • Dr Andy Goulding, PhD student (STFC studentship, 2008-2010); research fellow (CfA-Harvard, 2010-2014); NOW: research fellow (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: assistant Professor/Lecturer (Dartmouth College)
  • Dr George Lansbury, PhD student (STFC studentship, 2012-2016); NOW: Herchel fellow (University of Cambridge)
  • 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 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: Lecturer (University of Sheffield)
  • Mr Simon Murray, MSc by Research student (self funded), 2015-2016; NOW: industry (non academic)
  • Dr Manolis Rovilos, research fellow (Marie Curie Fellowship, 2012-2014); NOW: Patents Clerk (non academic)
  • Dr Flora Stanley, PhD student (Durham Doctoral Scholarship, 2012-2016); NPW: research fellow (Chalmers University, Sweden)

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 but that's no excuse!

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!).

The workshops and conferences that I have (co-)organised at Durham (or Dartmouth):

2016: Hidden Monsters - obscured AGN and connections to galaxy evolution at Dartmouth
2014: AGN vs star formation - the fate of the gas in galaxies at Durham
2012: Black-hole feedback workshop at Dartmouth
2011: Galaxy Formation conference at Durham
2010: What Drives the Growth of Black Holes workshop at Durham
..you can download a review paper written on the science presented at the workshop.
2007: PanSTARRS workshop at Durham

Some other useful resources:

Where is Dave today?
Curriculum Vitae
Durham Research Online instructions (Shaun Cole web page)
Durham grant codes (Shaun Cole web page)
Extragalactic telescope facilities
Graduate student job prospect 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