Associate Professor Christian Wolf
Areas of expertise
- Astronomical And Space Sciences 0201
Research interests
wide-field sky surveys, object classification and photometric redshift estimation
growth of supermassive black holes, early universe and varaibility
optical counterparts to gravitational-wave events
galaxy evolution through cosmic epochs and via environmental influence
dust in the Milky Way and star-forming galaxies
Biography
Jan 1999: PhD at Max-Planck-Institute of Astronomy Heidelberg, Germany
until 2001: Research Fellow at MPIA Heidelberg, PI of COMBO-17 survey
2001-2013: University of Oxford, UK (2004-2009 STFC Advanced Fellow)
from 2013: RSAA Mt Stromlo, ANU, Canberra, Australia
2016-2018: ANU Node Leader of CAASTRO (ARC Centre of Excellence in All-sky Astrophysics)
Researcher's projects
Ultra-luminous quasars and the growth of the most massive black holes in the early universe:
We use the SkyMapper Southern Survey together data from the Gaia and WISE satellites to identify the most luminous quasars in the early universe. Then we measure the masses of their black holes and investgate how fast early black holes are growing. Are they slowly growing from seeds that are more massive than we can explain? Or are the growing faster than the Eddington accretion llimit instead?
Classification in the SkyMapper Southern Survey
The SkyMapper Southern Survey will contain photometry for a billion objects in its next data release, which can be stars, galaxies, quasars, asteroids and artefacts. We have training sets for these and external information from astrometry and multi-wavelength missions. Using all the available information we can statistically classify every object in the survey, and using photometric redshifts we can estimate their distance without taking a spectrum.
Search for kilonovae from neutron-star collisions
SkyMapper is switched into an alert override mode as soon as gravitational waves from a merger event are recorded with LIGO/Virgo. We rapidly identify optical transients with SkyMapper and investigate them further. Which one is the kilonova from the collision and what does it tell us? Only one kilonova has been seen so far, in 2017. The next could be just around the corner.
Variability of quasar accretion disks
Using long-term light curves for thousands of quasars we study the variable luminosity of the accretion disks around their supermassive black holes. This can tell us about their sizes and temperature profiles, which are mostly unknown so far.
We also search for supermassive black holes whose accretion is only episodic and switches on and off on a timescale of years. These "changing-look AGN" are discovered more and more, but what is their distribution and what might cause their nature?
Strong flares from stars and other rare transients
With SkyMapper and other telescopes we monitor the sky for strong outbursts of light from stars and other unexplained bright transients. Are any of them visible to the naked eye, even though they originate from far away?
Publications
- Bilicki, M, Hoekstra, H, Brown, M et al 2018, 'Photometric redshifts for the Kilo-Degree Survey Machine-learning analysis with artificial neural networks', Astronomy and Astrophysics (Online), vol. 616, no. 69, pp. 22pp.
- Tortora, C, Napolitano, N, Spavone, M et al 2018, 'The first sample of spectroscopically confirmed ultra-compact massive galaxies in the Kilo Degree Survey', Monthly Notices of the Royal Astronomical Society, vol. 481, no. 4, pp. 4728-4752pp.
- Anderson, J, Pessi, P, Dessart, L et al. 2018, 'A nearby super-luminous supernova with a long pre-maximum & "plateau" and strong C II features', Astronomy and Astrophysics, vol. 620, no. 67, pp. 1-16pp.
- Tonry, J, Denneau, L, Flewelling, H et al 2018, 'The ATLAS All-Sky Stellar Reference Catalog', The Astrophysical Journal, vol. 867, no. 105, pp. -.
- Wolf, C, Weinzirl, T, Aragon-Salamanca, A et al 2018, 'OMEGA - OSIRIS mapping of emission-line galaxies in A901/2-IV. Extinction of star formation estimators with inclination', Monthly Notices of the Royal Astronomical Society, vol. 480, no. 3, pp. 3788-3799.
- Tran, A, Ong, C & Wolf, C 2018, 'Combining active learning suggestions', PeerJ Computer Science, vol. 4, no. e157, pp. 1-34.
- Amon, A, Heymans, C, Klaes, D et al 2018, 'KiDS-i-800: Comparing weak gravitational lensing measurements from same-sky surveys', Monthly Notices of the Royal Astronomical Society, vol. 477, no. 4, pp. 4285-4307pp.
- Alger, M, Banfield, J, Ong, C et al. 2018, 'Radio Galaxy Zoo: Machine learning for radio source host galaxy cross-identification', Monthly Notices of the Royal Astronomical Society, vol. 478, no. 4, pp. 5556-5572pp.
- Amon, A, Blake, C, Heymans, C et al 2018, 'KiDS+2dFLenS+GAMA: Testing the cosmological model with the EG statistic', Monthly Notices of the Royal Astronomical Society, vol. 479, no. 3, pp. 3422-3437pp.
- Farah, W, Flynn, C, Bailes, M et al. 2018, 'FRB microstructure revealed by the real-time detection of FRB170827', Monthly Notices of the Royal Astronomical Society, vol. 478, no. 1, pp. 1209-1217pp.
- Joudaki, S, Blake, C, Johnson, A et al. 2018, 'KiDS-450 + 2dFLenS: Cosmological parameter constraints from weak gravitational lensing tomography and overlapping redshift-space galaxy clustering', Monthly Notices of the Royal Astronomical Society, vol. 474, no. 4, pp. 4894-4924.
- Wolf, C, Bian, F, Onken, C et al 2018, 'Discovery of the Most Ultra-Luminous QSO Using GAIA, SkyMapper, and WISE', Publications of the Astronomical Society of Australia, vol. 35, pp. 1-6.
- Wolf, C, Onken, C, Luvaul, L et al 2018, 'SkyMapper Southern Survey: First Data Release (DR1)', Publications of the Astronomical Society of Australia, vol. 35, pp. 1-29.
- Weinzirl, T, Aragon-Salamanca, A, Gray, M et al 2017, 'OMEGA - OSIRIS Mapping of Emission-line Galaxies in A901/2 - III. Galaxy properties across projected phase space in A901/2', Monthly Notices of the Royal Astronomical Society, vol. 471, no. 1, pp. 182-200pp.
- Wolf, C, Johnson, A, Bilicki, M et al 2017, 'The 2-degree Field Lensing Survey: Photometric redshifts from a large new training sample to r < 19.5', Monthly Notices of the Royal Astronomical Society, vol. 466, no. 2, pp. 1582-1596pp.
- Scalzo, R, Yuan, F, Childress, M et al. 2017, 'The SkyMapper Transient Survey', Publications of the Astronomical Society of Australia, vol. 34, pp. e030 (13 pp).
- Murphy, T, Kaplan, D, Croft, S et al 2017, 'A search for long-time-scale, low-frequency radio transients', Monthly Notices of the Royal Astronomical Society, vol. 466, no. 2, pp. 1944-1953pp.
- Rodrıguez del Pino, B, Aragon-Salamanca, A, Chies-Santos, A et al 2017, 'OMEGA - OSIRIS Mapping of Emission-line Galaxies in A901/2 - II. Environmental influence on integrated star formation properties and AGN activity', Monthly Notices of the Royal Astronomical Society, vol. 467, no. 4, pp. 4200-4217pp..
- Naud, M, Artigau, E, Artigau, E et al 2017, 'PSYM-WIDE: A Survey for Large-separation Planetary-mass Companions to Late Spectral Type Members of Young Moving Groups', Astronomical Journal, vol. 154, no. 3, pp. 1-20pp.
- Johnson, A, Blake, C, Amon, A et al 2017, '2dFLenS and KiDS: Determining source redshift distributions with cross-correlations', Monthly Notices of the Royal Astronomical Society, vol. 465, no. 4, pp. 4118-4132pp.
- Hildebrandt, H, Choi, A, Heymans, C et al 2016, 'RCSLenS: The Red Cluster Sequence Lensing Survey', Monthly Notices of the Royal Astronomical Society, vol. 463, no. 1, pp. 635-654pp.
- Altin, P, Charlton, P, Chow, J et al. 2016, 'LOCALIZATION AND BROADBAND FOLLOW-UP OF THE GRAVITATIONAL-WAVE TRANSIENT GW 150914', Astrophysical Journal Letters, vol. 826, no. 1, pp. 8pp.
- Blake, C, Amon, A, Childress, M et al. 2016, 'The 2-degree Field Lensing Survey: Design and clustering measurements', Monthly Notices of the Royal Astronomical Society, vol. 462, no. 4, pp. 4240-4265.
- Hoyos, C, Aragon-Salamanca, A, Gray, M et al 2016, 'Linking the structural properties of galaxies and their star formation histories with STAGES', Monthly Notices of the Royal Astronomical Society, vol. 455, no. 1, pp. 295-307.
- van der Wel, A, Noeske, K, Bezanson, R et al. 2016, 'THE VLT LEGA-C SPECTROSCOPIC SURVEY: The PHYSICS of GALAXIES at A LOOKBACK TIME of 7 Gyr', Astrophysical Journal Supplement Series, vol. 223, no. 2, pp. 1-12.
- Nataf, D, Gonzalez, O, Casagrande, L et al 2016, 'Interstellar extinction curve variations towards the inner Milky Way: A challenge to observational cosmology', Monthly Notices of the Royal Astronomical Society, vol. 456, no. 3, pp. 2692-2706.
- Abbott, B, Abbott, R, Abbott, T et al 2016, 'Supplement: "Localization and broadband follow-up of the gravitational-wave transient GW150914"', Astrophysical Journal Supplement Series, vol. 225, no. 1, pp. (15pp).
- Petroff, E, Bailes, M, Barr, E et al 2015, 'A real-time fast radio burst: Polarization detection and multiwavelength follow-up', Monthly Notices of the Royal Astronomical Society, vol. 447, no. 1, pp. 246-255.
- Chies-Santos, A, Rodrıguez del Pino, B, Aragon-Salamanca, A et al 2015, 'OMEGA - OSIRIS mapping of emission-line galaxies in A901/2-I. survey description, data analysis, and star formation and AGN activity in the highest density regions', Monthly Notices of the Royal Astronomical Society, vol. 450, no. 4, pp. 4458-4474.
- Childress, M, Hillier, D, Seitenzahl, I et al. 2015, 'Measuring nickel masses in Type Ia supernovae using cobalt emission in nebular phase spectra', Monthly Notices of the Royal Astronomical Society, vol. 454, no. 4, pp. 3816-3842.
- Maltby, D, Aragon-Salamanca, A, Gray, M et al 2015, 'The environmental dependence of the structure of galactic discs in STAGES S0 galaxies: Implications for S0 formation', Monthly Notices of the Royal Astronomical Society, vol. 447, no. 2, pp. 1506-1530.
- Childress, M, Wolf, C & Zahid, H 2014, 'Ages of Type Ia supernovae over cosmic time', Monthly Notices of the Royal Astronomical Society, vol. 445, no. 2, pp. 1898-1911.
- Wolf, C 2014, 'Milky Way dust extinction measured with QSOs', Monthly Notices of the Royal Astronomical Society, vol. 445, no. 4, pp. 4252-4258.
- Bosch, B, Bohm, A, Wolf, C et al 2013, 'Tully-Fisher analysis of the multiple cluster system Abell 901/902', Astronomy and Astrophysics, vol. 554, p. 15.
- Bosch, B, Bohm, A, Wolf, C et al 2013, 'Ram pressure and dusty red galaxies - Key factors in the evolution of the multiple cluster system Abell 901/902', Astronomy and Astrophysics, vol. 549, pp. A142.
- Bohm, A, Wisotzki, L, Bell, E et al 2013, 'AGN host galaxies at redshift z approximate to 0.7: peculiar or not?', Astronomy and Astrophysics, vol. 549, pp. A46.
- Hoyos, C, Aragon-Salamanca, A, Gray, M et al 2012, 'A new automatic method to identify galaxy mergers - I. Description and application to the Space Telescope A901/902 Galaxy Evolution Survey', Monthly Notices of the Royal Astronomical Society, vol. 419, no. 3, pp. 2703-2724.
- Maltby, D, Hoyos, C, Gray, M et al 2012, 'Antitruncated stellar light profiles in the outer regions of STAGES spiral galaxies: Bulge or disc related?', Monthly Notices of the Royal Astronomical Society, vol. 420, no. 3, pp. 2475-2479.
- Simon, P, Heymans, C, Schrabback, T et al 2012, 'Spatial matter density mapping of the STAGES Abell A901/2 supercluster field with 3D lensing', Monthly Notices of the Royal Astronomical Society, vol. 419, no. 2, pp. 998-1016.
- Maltby, D, Gray, M, Aragon-Salamanca, A et al 2012, 'The environmental dependence of the structure of outer galactic discs in STAGES spiral galaxies', Monthly Notices of the Royal Astronomical Society, vol. 419, no. 1, pp. 669-686.
- Nicol, M, Meisenheimer, K, Wolf, C et al 2011, 'Red-sequence galaxies at high redshift by the COMBO-17+4 survey', The Astrophysical Journal, vol. 727, no. 1, p. 51.
- Berger, E, Chornock, R, Holmes, T et al. 2011, 'THE SPECTROSCOPIC CLASSIFICATION AND EXPLOSION PROPERTIES OF SN 2009nz ASSOCIATED WITH GRB 091127 AT z=0.490', The Astrophysical Journal, vol. 743, no. 2, p. 204.
- Cucchiara, A, Levan, A, Fox, D et al 2011, 'A photometric redshift of z ∼ 9.4 for GRB 090429B', The Astrophysical Journal, vol. 736, no. 1, p. 12.
- Marinova, I, Jogee, S, Heiderman, A et al 2011, 'Barred disks in dense environments', Memorie Della Societa Astronomica Italiana, vol. 18, pp. 61-67.
- Justham, S, Podsiadlowski, P, Han, Z et al. 2010, 'Helium-rich hot subdwarfs and single low-mass white dwarfs: Formation mechanisms and further implications', Astrophysics and Space Science, vol. 329, no. 1-2, pp. 3-10.
- Hildebrandt, H, Arnouts, S, Capak, P et al 2010, 'PHAT: PHoto-z accuracy testing', Astronomy and Astrophysics, vol. 523, no. 2, pp. A31.
- Maltby, D, Aragon-Salamanca, A, Gray, M et al 2010, 'The environmental dependence of the stellar-mass-size relation in STAGES galaxies', Monthly Notices of the Royal Astronomical Society, vol. 402, no. 1, pp. 282-294.
- Roser, H, Hippelein, H, Wolf, C et al 2010, 'The Heidelberg InfraRed Optical Cluster Survey (HIROCS)', Astronomy and Astrophysics, vol. 513, no. 3, pp. A15.
- Robaina, A, Bell, E, van der Wel, A et al 2010, 'The merger-driven evolution of massive galaxies', The Astrophysical Journal, vol. 719, no. 1, pp. 844-850.
- Simon, P, Hetterscheidt, M, Wolf, C et al 2009, 'Relative clustering and the joint halo occupation distribution of red sequence and blue-cloud galaxies in COMBO-17', Monthly Notices of the Royal Astronomical Society, vol. 398, no. 2, pp. 807-831.
- Wolf, C 2009, 'Bayesian photometric redshifts with empirical training sets', Monthly Notices of the Royal Astronomical Society, vol. 397, no. 1, pp. 520-533.
- Galazzi, A, Bell, E, Wolf, C et al 2009, 'Obscured star formation in intermediate-density environments: A Spitzer study of the Abell 901/902 supercluster', The Astrophysical Journal, vol. 690, no. 2, pp. 1883-1900.
- Justham, S, Wolf, C, Podsiadlowski, P et al. 2009, 'Type la supernovae and the formation of single low-mass white dwarfs', Astronomy and Astrophysics, vol. 493, no. 3, pp. 1081-1091.
- Gray, M, Wolf, C, Barden, M et al 2009, 'STAGES: The Space Telescope A901/2 Galaxy Evolution Survey', Monthly Notices of the Royal Astronomical Society, vol. 393, no. 4, pp. 1275-1301.
- Jogee, S, Miller, S, Penner, K et al 2009, 'History of galaxy interactions and their impact on star formation over the last 7 Gyr from GEMS', The Astrophysical Journal, vol. 697, no. 2, pp. 1971-1992.
- Wolf, C, Aragon-Salamanca, A, Balogh, M et al 2009, 'The STAGES view of red spirals and dusty red galaxies: Mass-dependent quenching of star formation in cluster infall', Monthly Notices of the Royal Astronomical Society, vol. 393, no. 4, pp. 1302-1323.
- Heiderman, A, Jogee, S, Marinova, I et al 2009, 'Interacting galaxies in the A901/902 supercluster with STAGES', The Astrophysical Journal, vol. 705, no. 2, pp. 1433-1455.
- Robaina, A, Bell, E, Skelton, R et al 2009, 'Less than 10 percent of star formation in z ~ 0.6 massive galaxies is triggered by major interactions', The Astrophysical Journal, vol. 704, no. 1, pp. 324-340.
- Barazza, F, Wolf, C, Gray, M et al 2009, 'Relating basic properties of bright early-type dwarf galaxies to their location in Abell 901/902', Astronomy and Astrophysics, vol. 508, no. 2, pp. 665-675.
- Marinova, I, Jogee, S, Heiderman, A et al 2009, 'Barred galaxies in the Abell 901/2 supercluster with STAGES', The Astrophysical Journal, vol. 698, pp. 1639-1658.
- Tanvir, N, Fox, D, Levan, A et al 2009, 'A γ-ray burst at a redshift of z ≈ 8.2', Nature, vol. 461, no. 7268, pp. 1254-1257.
- Somerville, R, Barden, M, Rix, H et al 2008, 'An explanation for the observed weak size evolution of disk galaxies', The Astrophysical Journal, vol. 672, no. 2, pp. 776-786.
- Schawinski, K, Justham, S, Wolf, C et al. 2008, 'Supernova shock breakout from a red supergiant', Science, vol. 321, no. 5886, pp. 223-226.
- Hildebrandt, H, Wolf, C & Benitez, N 2008, 'A blind test of photometric redshifts on ground-based data', Astronomy and Astrophysics, vol. 480, no. 3, pp. 703-714.
- Heymans, C, Gray, M, Peng, C et al 2008, 'The dark matter environment of the Abell 901/902 supercluster: A weak lensing analysis of the HST STAGES survey', Monthly Notices of the Royal Astronomical Society, vol. 385, no. 3, pp. 1431-1442.
- Lehmer, B, Brandt, W, Alexander, D et al 2008, 'Tracing the mass-dependent star formation history of late-type galaxies using X-ray emission: Results from the chandra deep fields', The Astrophysical Journal, vol. 681, no. 2, pp. 1163-1182.
- Caldwell, J, McIntosh, D, Rix, H et al 2008, 'GEMS survey data and catalog', Astrophysical Journal Supplement Series, vol. 174, no. 1, pp. 136-144.
- Wolf, C, Hildebrandt, H, Taylor, E et al 2008, 'Calibration update of the COMBO-17 CDFS catalogue', Astronomy and Astrophysics, vol. 492, no. 3, pp. 933-936.
Projects and Grants
Grants information is drawn from ARIES. To add or update Projects or Grants information please contact your College Research Office.
- The growth of giant black holes in the early Universe (Primary Investigator)
- Project to enhance ASVO-SkyMapper under the National eResearch Collaboration Tools and resources (NeCTAR) Project (Secondary Investigator)
