The cycle of life, death and rebirth in massive early-type galaxies; star formation, black-holes and feedback
Lead Research Organisation:
University of Hertfordshire
Department Name: Science and Technology RI
Abstract
My research focuses on understanding the biggest galaxies that exist around us in the local universe. These objects are interesting because they are thought to be the end point of galaxy evolution. They are made up of billions of old stars, have red optical colours, and are generally thought to be free of cold gas - the fuel for new stars. Thus they are often described as "red and dead". Astronomers still don't fully know what caused these galaxies to die off, or if they can come back to life again. It is these processes that I am investigating.
One of the ways astronomers think these massive galaxies become "red and dead" is due to the supermassive black-holes that lie at their cores. These enigmatic objects are clearly linked to galaxy formation, as they seem to grow in step with their galaxy host. In order to understand the role of black holes in the formation of galaxies, I developed a new technique to measure their masses, by tracing the motions of molecular gas clouds swirling around them. This technique is exciting, because it opens up the possibility of measuring black hole masses more accurately, and in more galaxies than ever before. As part of my Rutherford fellowship I aim to use this technique to reveal the dark monsters lurking at the hearts of nearby galaxies.
When black holes swallow matter they emit large amounts of high energy light, and can accelerate large jets of particles. Both of these processes can affect gas clouds, throwing them out of galaxies. These outflows are one mechanism that can help form the gas-poor massive galaxies I study. A few years ago I helped identify one of the nearest examples of a black hole expelling large amounts of gas in this way. During my Rutherford fellowship I will use the chemistry of the gas in this outflow to determine whether it is the extremely strong light from the black hole, or the jet of particles that is causing the outflow we see. This will give us one more piece of the puzzle, helping to explain why most massive galaxies with big black holes are gas poor.
Massive galaxies, like the ones I study, don't have to stay "red and dead". The can come back to life if material from dying stars can cool and become fuel for a new generation of stars. They can also merge with other small galaxies and steal their fuel. Around 1/4 of the massive "red and dead" galaxies around us today are currently in the process of being reborn. Understanding which process causes this, and what effect surrounding galaxies have, will allow us to determine whether these galaxies are destined to fail and go back to being "red and dead", or if they can eventually come back to life fully.
I have discovered that these objects that have obtained fuel for star-formation, don't seem to be using it very effectively. They are very inefficient at forming stars when compared to galaxies like our own Milky Way. I aim to find out why this is happening, and what this can tell us about the physics controlling star formation in the universe.
One of the ways astronomers think these massive galaxies become "red and dead" is due to the supermassive black-holes that lie at their cores. These enigmatic objects are clearly linked to galaxy formation, as they seem to grow in step with their galaxy host. In order to understand the role of black holes in the formation of galaxies, I developed a new technique to measure their masses, by tracing the motions of molecular gas clouds swirling around them. This technique is exciting, because it opens up the possibility of measuring black hole masses more accurately, and in more galaxies than ever before. As part of my Rutherford fellowship I aim to use this technique to reveal the dark monsters lurking at the hearts of nearby galaxies.
When black holes swallow matter they emit large amounts of high energy light, and can accelerate large jets of particles. Both of these processes can affect gas clouds, throwing them out of galaxies. These outflows are one mechanism that can help form the gas-poor massive galaxies I study. A few years ago I helped identify one of the nearest examples of a black hole expelling large amounts of gas in this way. During my Rutherford fellowship I will use the chemistry of the gas in this outflow to determine whether it is the extremely strong light from the black hole, or the jet of particles that is causing the outflow we see. This will give us one more piece of the puzzle, helping to explain why most massive galaxies with big black holes are gas poor.
Massive galaxies, like the ones I study, don't have to stay "red and dead". The can come back to life if material from dying stars can cool and become fuel for a new generation of stars. They can also merge with other small galaxies and steal their fuel. Around 1/4 of the massive "red and dead" galaxies around us today are currently in the process of being reborn. Understanding which process causes this, and what effect surrounding galaxies have, will allow us to determine whether these galaxies are destined to fail and go back to being "red and dead", or if they can eventually come back to life fully.
I have discovered that these objects that have obtained fuel for star-formation, don't seem to be using it very effectively. They are very inefficient at forming stars when compared to galaxies like our own Milky Way. I aim to find out why this is happening, and what this can tell us about the physics controlling star formation in the universe.
Organisations
- University of Hertfordshire (Lead Research Organisation)
- NRC Herzberg Institute of Astrophysics (NRC-HIA) (Collaboration)
- European Southern Observatory (ESO) (Collaboration)
- Graduate University for Advanced Studies (SOKENDAI), Okazaki (Collaboration)
- University of Hertfordshire (Collaboration)
- Princeton University (Collaboration)
- UNIVERSITY OF OXFORD (Collaboration)
- University of Cologne (Collaboration)
- University of California, Berkeley (Collaboration)
- Max Planck Society (Collaboration)
- Leibniz Association (Collaboration)
- Observatory of Paris (Collaboration)
- CARDIFF UNIVERSITY (Fellow)
People |
ORCID iD |
Timothy Davis (Principal Investigator / Fellow) |
Publications
Agius N
(2015)
H-ATLAS/GAMA and HeViCS - dusty early-type galaxies in different environments
in Monthly Notices of the Royal Astronomical Society
Alatalo K
(2013)
NGC 1266 AS A LOCAL CANDIDATE FOR RAPID CESSATION OF STAR FORMATION
in The Astrophysical Journal
Alatalo K
(2015)
Evidence of boosted 13CO/12CO ratio in early-type galaxies in dense environments
in Monthly Notices of the Royal Astronomical Society
Alatalo K
(2014)
SUPPRESSION OF STAR FORMATION IN NGC 1266
in The Astrophysical Journal
Brown T
(2021)
VERTICO: The Virgo Environment Traced in CO Survey
in The Astrophysical Journal Supplement Series
Davis T
(2017)
Spatially resolved variations of the IMF mass normalization in early-type galaxies as probed by molecular gas kinematics
in Monthly Notices of the Royal Astronomical Society
Davis T
(2022)
WISDOM Project - X. The morphology of the molecular ISM in galaxy centres and its dependence on galaxy structure
in Monthly Notices of the Royal Astronomical Society
Davis T
(2015)
The MASSIVE survey - III. Molecular gas and a broken Tully-Fisher relation in the most massive early-type galaxies
in Monthly Notices of the Royal Astronomical Society
Davis T
(2015)
Molecular and atomic gas in dust lane early-type galaxies - I. Low star formation efficiencies in minor merger remnants
in Monthly Notices of the Royal Astronomical Society
Davis T
(2014)
A figure of merit for black hole mass measurements with molecular gas
in Monthly Notices of the Royal Astronomical Society
Davis T
(2018)
WISDOM Project - III. Molecular gas measurement of the supermassive black hole mass in the barred lenticular galaxy NGC4429
in Monthly Notices of the Royal Astronomical Society
Davis T
(2014)
The ATLAS3D Project - XXVIII. Dynamically driven star formation suppression in early-type galaxies
in Monthly Notices of the Royal Astronomical Society
Davis T
(2014)
Systematic variation of the 12CO/13CO ratio as a function of star formation rate surface density
in Monthly Notices of the Royal Astronomical Society
Davis T
(2017)
WISDOM Project - II. Molecular gas measurement of the supermassive black hole mass in NGC 4697
in Monthly Notices of the Royal Astronomical Society
Dawson J
(2021)
A self-supervised, physics-aware, Bayesian neural network architecture for modelling galaxy emission-line kinematics
in Monthly Notices of the Royal Astronomical Society
De Breuck C
(2014)
ALMA resolves turbulent, rotating [CII] emission in a young starburst galaxy at z = 4.8
in Astronomy & Astrophysics
Den Heijer M
(2015)
The H I Tully-Fisher relation of early-type galaxies
in Astronomy & Astrophysics
Duc P
(2015)
The ATLAS3D project - XXIX. The new look of early-type galaxies and surrounding fields disclosed by extremely deep optical images
in Monthly Notices of the Royal Astronomical Society
Fuller C
(2014)
The Herschel Fornax Cluster Survey II: FIR properties of optically selected Fornax cluster galaxies
in Monthly Notices of the Royal Astronomical Society
Fuller C
(2016)
H-ATLAS: the far-infrared properties of galaxies in and around the Coma cluster
in Monthly Notices of the Royal Astronomical Society
Hogarth L
(2021)
Centrally concentrated molecular gas driving galactic-scale ionized gas outflows in star-forming galaxies
in Monthly Notices of the Royal Astronomical Society
Husemann B
(2016)
The Close AGN Reference Survey (CARS) What is causing Mrk 1018's return to the shadows after 30 years??
in Astronomy & Astrophysics
Husemann B
(2017)
Integral field spectroscopy of nearby quasi-stellar objects - II. Molecular gas content and conditions for star formation
in Monthly Notices of the Royal Astronomical Society
Krumpe M
(2017)
The Close AGN Reference Survey (CARS) Mrk 1018 halts dimming and experiences strong short-term variability?
in Astronomy & Astrophysics
Lagos C
(2015)
The origin of the atomic and molecular gas contents of early-type galaxies - II. Misaligned gas accretion
in Monthly Notices of the Royal Astronomical Society
Lagos C
(2017)
Angular momentum evolution of galaxies in EAGLE
in Monthly Notices of the Royal Astronomical Society
Lagos C
(2018)
Quantifying the impact of mergers on the angular momentum of simulated galaxies
in Monthly Notices of the Royal Astronomical Society
Lagos C
(2014)
The origin of the atomic and molecular gas contents of early-type galaxies - I. A new test of galaxy formation physics
in Monthly Notices of the Royal Astronomical Society
Lelli F
(2021)
A massive stellar bulge in a regularly rotating galaxy 1.2 billion years after the Big Bang.
in Science (New York, N.Y.)
Li X
(2020)
The MALATANG survey: dense gas and star formation from high-transition HCN and HCO+ maps of NGC 253
in Monthly Notices of the Royal Astronomical Society
Liu L
(2021)
WISDOM Project - IX. Giant molecular clouds in the lenticular galaxy NGC 4429: effects of shear and tidal forces on clouds
in Monthly Notices of the Royal Astronomical Society
McDermid R
(2015)
The ATLAS3D Project - XXX. Star formation histories and stellar population scaling relations of early-type galaxies
in Monthly Notices of the Royal Astronomical Society
McDermid R
(2014)
CONNECTION BETWEEN DYNAMICALLY DERIVED INITIAL MASS FUNCTION NORMALIZATION AND STELLAR POPULATION PARAMETERS
in The Astrophysical Journal
McElroy R
(2016)
The Close AGN Reference Survey (CARS) Mrk 1018 returns to the shadows after 30 years as a Seyfert 1
in Astronomy & Astrophysics
Naab T
(2014)
The ATLAS3D project - XXV. Two-dimensional kinematic analysis of simulated galaxies and the cosmological origin of fast and slow rotators
in Monthly Notices of the Royal Astronomical Society
Nguyen D
(2020)
The MBHBM ? Project. I. Measurement of the Central Black Hole Mass in Spiral Galaxy NGC 3504 Using Molecular Gas Kinematics
in The Astrophysical Journal
Nyland K
(2016)
The atlas 3D Project - XXXI. Nuclear radio emission in nearby early-type galaxies
in Monthly Notices of the Royal Astronomical Society
Nyland K
(2017)
Star formation in nearby early-type galaxies: the radio continuum perspective
in Monthly Notices of the Royal Astronomical Society
Nyland K
(2017)
A Multi-wavelength Study of the Turbulent Central Engine of the Low-mass AGN Hosted by NGC 404
in The Astrophysical Journal
Onishi K
(2017)
WISDOM project - I. Black hole mass measurement using molecular gas kinematics in NGC 3665
in Monthly Notices of the Royal Astronomical Society
Pandya V
(2017)
The MASSIVE Survey. VI. The Spatial Distribution and Kinematics of Warm Ionized Gas in the Most Massive Local Early-type Galaxies
in The Astrophysical Journal
Partnership A
(2015)
THE 2014 ALMA LONG BASELINE CAMPAIGN: AN OVERVIEW
in The Astrophysical Journal
Ruffa I
(2020)
The AGN fuelling/feedback cycle in nearby radio galaxies - III. 3D relative orientations of radio jets and CO discs and their interaction
in Monthly Notices of the Royal Astronomical Society
Ruffa I
(2022)
The AGN fuelling/feedback cycle in nearby radio galaxies - IV. Molecular gas conditions and jet-ISM interaction in NGC 3100
in Monthly Notices of the Royal Astronomical Society
Serra P
(2014)
The ATLAS3D project - XXVI. H i discs in real and simulated fast and slow rotators
in Monthly Notices of the Royal Astronomical Society
Shabala S
(2017)
Delayed triggering of radio active galactic nuclei in gas-rich minor mergers in the local Universe
in Monthly Notices of the Royal Astronomical Society
Thater S
(2022)
Cross-checking SMBH mass estimates in NGC 6958 - I. Stellar dynamics from adaptive optics-assisted MUSE observations
in Monthly Notices of the Royal Astronomical Society
Tiley A
(2016)
The Tully-Fisher relation of COLD GASS Galaxies
in Monthly Notices of the Royal Astronomical Society
Tojeiro R
(2020)
Decoupling the rotation of stars and gas - II. The link between black hole activity and simulated IFU kinematics in IllustrisTNG
in Monthly Notices of the Royal Astronomical Society
Topal S
(2016)
Molecular gas kinematics and line diagnostics in early-type galaxies: NGC 4710 and NGC 5866
in Monthly Notices of the Royal Astronomical Society
Description | In this reporting period I discovered that the most massive galaxies in our universe have the same amount of cold gas as their lower mass compatriots. This gas appears to be primarily accreted from external sources, form stars very slowly, and takes a long time to relax into the galaxy potential. |
Exploitation Route | These findings are instrumental in understanding the evolution of the most massive galaxies in our universe, and their future evolution. This will allow future large surveys (such as SAMI and MANGA) to constrain the gas rich merger rate in the local universe, which is directly related to the LCDM model. |
Sectors | Other |
Title | KinMS_mcmc |
Description | Linking the KinMS tools to an MCMC wrapper to better fit SMBH masses as part of the WISDOM project |
Type Of Material | Data analysis technique |
Year Produced | 2014 |
Provided To Others? | Yes |
Impact | The model has been used by various other groups working in this field. |
URL | https://github.com/TimothyADavis/KinMS |
Description | CARS |
Organisation | European Southern Observatory (ESO) |
Country | Germany |
Sector | Charity/Non Profit |
PI Contribution | I lead the molecular followup of CARS sources, especially those with outflows. |
Collaborator Contribution | The other team members deal with the MUSE IFU data that forms the basis of the survey, and the ancillary data (radio, X-ray, etc). |
Impact | First papers incoming shortly. |
Start Year | 2015 |
Description | CARS |
Organisation | Leibniz Association |
Department | Leibniz Institute for Astrophysics Potsdam |
Country | Germany |
Sector | Academic/University |
PI Contribution | I lead the molecular followup of CARS sources, especially those with outflows. |
Collaborator Contribution | The other team members deal with the MUSE IFU data that forms the basis of the survey, and the ancillary data (radio, X-ray, etc). |
Impact | First papers incoming shortly. |
Start Year | 2015 |
Description | CARS |
Organisation | Observatory of Paris |
Country | France |
Sector | Academic/University |
PI Contribution | I lead the molecular followup of CARS sources, especially those with outflows. |
Collaborator Contribution | The other team members deal with the MUSE IFU data that forms the basis of the survey, and the ancillary data (radio, X-ray, etc). |
Impact | First papers incoming shortly. |
Start Year | 2015 |
Description | CARS |
Organisation | University of Cologne |
Department | Department of Physics |
Country | Germany |
Sector | Academic/University |
PI Contribution | I lead the molecular followup of CARS sources, especially those with outflows. |
Collaborator Contribution | The other team members deal with the MUSE IFU data that forms the basis of the survey, and the ancillary data (radio, X-ray, etc). |
Impact | First papers incoming shortly. |
Start Year | 2015 |
Description | CARS |
Organisation | University of Cologne |
Department | Department of Physics |
Country | Germany |
Sector | Academic/University |
PI Contribution | I lead the molecular followup of CARS sources, especially those with outflows. |
Collaborator Contribution | The other team members deal with the MUSE IFU data that forms the basis of the survey, and the ancillary data (radio, X-ray, etc). |
Impact | First papers incoming shortly. |
Start Year | 2015 |
Description | MASSIVE |
Organisation | Max Planck Society |
Department | Max Planck Institute For Extraterrestrial Physics (MPE) |
Country | Germany |
Sector | Academic/University |
PI Contribution | I lead the molecular gas aspects of the survey, providing crucial information on the cold phases of the ISM in the most massive galaxies in our universe. |
Collaborator Contribution | UCB and Princeton staff members primarily supplied the optical IFU information that the survey is based on, while other members provided analysis and ancillary data sets. |
Impact | 10.1088/0004-637X/795/2/158 10.1088/0004-637X/807/1/11 10.1093/mnras/stv2313 |
Start Year | 2014 |
Description | MASSIVE |
Organisation | NRC Herzberg Institute of Astrophysics (NRC-HIA) |
Country | Canada |
Sector | Academic/University |
PI Contribution | I lead the molecular gas aspects of the survey, providing crucial information on the cold phases of the ISM in the most massive galaxies in our universe. |
Collaborator Contribution | UCB and Princeton staff members primarily supplied the optical IFU information that the survey is based on, while other members provided analysis and ancillary data sets. |
Impact | 10.1088/0004-637X/795/2/158 10.1088/0004-637X/807/1/11 10.1093/mnras/stv2313 |
Start Year | 2014 |
Description | MASSIVE |
Organisation | Princeton University |
Department | Department of Astrophysical Sciences |
Country | United States |
Sector | Academic/University |
PI Contribution | I lead the molecular gas aspects of the survey, providing crucial information on the cold phases of the ISM in the most massive galaxies in our universe. |
Collaborator Contribution | UCB and Princeton staff members primarily supplied the optical IFU information that the survey is based on, while other members provided analysis and ancillary data sets. |
Impact | 10.1088/0004-637X/795/2/158 10.1088/0004-637X/807/1/11 10.1093/mnras/stv2313 |
Start Year | 2014 |
Description | MASSIVE |
Organisation | University of California, Berkeley |
Department | Department of Astronomy |
Country | United States |
Sector | Academic/University |
PI Contribution | I lead the molecular gas aspects of the survey, providing crucial information on the cold phases of the ISM in the most massive galaxies in our universe. |
Collaborator Contribution | UCB and Princeton staff members primarily supplied the optical IFU information that the survey is based on, while other members provided analysis and ancillary data sets. |
Impact | 10.1088/0004-637X/795/2/158 10.1088/0004-637X/807/1/11 10.1093/mnras/stv2313 |
Start Year | 2014 |
Description | WISDOM |
Organisation | Graduate University for Advanced Studies (SOKENDAI), Okazaki |
Country | Japan |
Sector | Academic/University |
PI Contribution | I co-lead the team, overseeing strategy, coordinating observing applications and distributing the workload. |
Collaborator Contribution | The other partners provide expertise, and work on the outputs of the observational program. Some of the research outputs are also being lead from these other institutes. |
Impact | A figure of merit for black hole mass measurements with molecular gas, MNRAS, 2014, Volume 443, Issue 1, p.911-918 A black-hole mass measurement from molecular gas kinematics in NGC4526. Nature, 2013, 494, 328-330 |
Start Year | 2013 |
Description | WISDOM |
Organisation | University of California, Berkeley |
Department | Department of Astronomy |
Country | United States |
Sector | Academic/University |
PI Contribution | I co-lead the team, overseeing strategy, coordinating observing applications and distributing the workload. |
Collaborator Contribution | The other partners provide expertise, and work on the outputs of the observational program. Some of the research outputs are also being lead from these other institutes. |
Impact | A figure of merit for black hole mass measurements with molecular gas, MNRAS, 2014, Volume 443, Issue 1, p.911-918 A black-hole mass measurement from molecular gas kinematics in NGC4526. Nature, 2013, 494, 328-330 |
Start Year | 2013 |
Description | WISDOM |
Organisation | University of Hertfordshire |
Department | Centre for Astrophysics Research (CAR) |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | I co-lead the team, overseeing strategy, coordinating observing applications and distributing the workload. |
Collaborator Contribution | The other partners provide expertise, and work on the outputs of the observational program. Some of the research outputs are also being lead from these other institutes. |
Impact | A figure of merit for black hole mass measurements with molecular gas, MNRAS, 2014, Volume 443, Issue 1, p.911-918 A black-hole mass measurement from molecular gas kinematics in NGC4526. Nature, 2013, 494, 328-330 |
Start Year | 2013 |
Description | WISDOM |
Organisation | University of Oxford |
Department | Department of Physics |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | I co-lead the team, overseeing strategy, coordinating observing applications and distributing the workload. |
Collaborator Contribution | The other partners provide expertise, and work on the outputs of the observational program. Some of the research outputs are also being lead from these other institutes. |
Impact | A figure of merit for black hole mass measurements with molecular gas, MNRAS, 2014, Volume 443, Issue 1, p.911-918 A black-hole mass measurement from molecular gas kinematics in NGC4526. Nature, 2013, 494, 328-330 |
Start Year | 2013 |