Research

Magnifying the Distant Universe

My research is concerned with distant galaxies, so far away that their light has taken most of the age of the Universe to reach us. In particular, I use the effect of gravitational lensing to magnify distant galaxies so that we can study them in more detail.

Below, you will find my most commonly referenced figures, with downloadable, machine-readable data tables, as well as a full publications list.


The UV Luminosity Function at z > 6

Fig 1. The UV luminosity function at z ~ 6, from Livermore et al. (2017).

Observations of the galaxy population at z > 6 (seen during the first billion years after the Big Bang) indicate that the faint-end slope of the UV luminosity function is steep (α ~ -2), suggesting that faint galaxies may have dominated the ionizing photon budget during reionization. This motivates understanding the faint-end slope, and determining the lower magnitude limit towards which it extends. Using gravitational lensing, we can find these ultra-faint galaxies. So far, there is no evidence of a turnover in the luminosity function to limits as low as MUV ~ -13 at z ~ 6.

Luminosity function data points are downloadable in ASCII format here:
z ~ 6; z ~ 7; z ~ 8


Star forming clumps in gravitationally lensed galaxies

Fig 2. Relation between star formation rate (SFR) in clumps and their sizes, from Livermore et al. (2015).

Observations of distant galaxies have revealed a population quite unlike that found in the local Universe; at high redshift, galaxies form stars more rapidly than they do locally, and their morphologies are often dominated by large clumps. While large-scale statistical studies can reveal these trends in overall properties, a detailed understanding of the processes involved in galaxy evolution in the early Universe requires high-resolution, spatially-resolved data.

My PhD research focused on using gravitational lensing to achieve the required spatial resolution in galaxies at 1 < z < 4. By targeting distant galaxies that lie behind massive foreground clusters, we are able to benefit from lensing magnification factors of up to 50x, resulting in spatial resolution of order ~100pc. Thus, we can isolate individual clumps or HII regions in high-redshift galaxies with 'normal' luminosities and star formation rates for their redshift, and study them in unprecedented detail.

Data on the star-forming clumps I observed is downloadable in ASCII format here:
From Livermore et al. (2012): HST narrowband imaging of galaxies at 1 < z < 1.5. Contains clump size and star formation rate.
From Livermore et al. (2015): integral field spectroscopy of galaxies at 1 < z < 4. Contains clump size, star formation rate and velocity dispersion.


Publications

Automatically retrieved from ADS.

  1. The Sizes of z\sim9-10 Galaxies Identified in the BoRG Survey
    Holwerda, Bridge, Steele, ..., Livermore, et al., 2020,
    eprint arXiv:2005.03515
    ADS Link

  2. RELICS: Reionization Lensing Cluster Survey
    Coe, Salmon, Bradač, ..., Livermore, et al., 2019,
    The Astrophysical Journal, Volume 884, Issue 1, article id. 85, 24 pp. (2019).
    ADS Link

  3. The brightest galaxies in the first 700 Myr: Building Hubble's legacy of large area IR imaging for JWST and beyond
    Trenti, Bernard, Bouwens, ..., Livermore, et al., 2019,
    HST Proposal. Cycle 26, ID. #16005
    ADS Link

  4. Conditions for Reionizing the Universe with a Low Galaxy Ionizing Photon Escape Fraction
    Finkelstein, D'Aloisio, Paardekooper, ..., Livermore, et al., 2019,
    The Astrophysical Journal, Volume 879, Issue 1, article id. 36, 34 pp. (2019).
    ADS Link

  5. On the observability of individual Population III stars and their stellar-mass black hole accretion disks through cluster caustic transits
    Windhorst, Alpaslan, Andrews, ..., Livermore, et al., 2019,
    Astro2020: Decadal Survey on Astronomy and Astrophysics, science white papers, no. 449; Bulletin of the American Astronomical Society, Vol. 51, Issue 3, id. 449 (2019)
    ADS Link

  6. RELICS: High-resolution Constraints on the Inner Mass Distribution of the z = 0.83 Merging Cluster RXJ0152.7-1357 from Strong Lensing
    Acebron, Alon, Zitrin, ..., Livermore, et al., 2019,
    The Astrophysical Journal, Volume 874, Issue 2, article id. 132, 13 pp. (2019).
    ADS Link

  7. RELICS: Strong Lensing Analysis of MACS J0417.5-1154 and Predictions for Observing the Magnified High-redshift Universe with JWST
    Mahler, Sharon, Fox, ..., Livermore, et al., 2019,
    The Astrophysical Journal, Volume 873, Issue 1, article id. 96, 15 pp. (2019).
    ADS Link

  8. Observational determination of the galaxy bias from cosmic variance with a random pointing survey: clustering of z ∼ 2 galaxies from Hubble's BoRG survey
    Cameron, Trenti, Livermore, et al., 2019,
    Monthly Notices of the Royal Astronomical Society, Volume 483, Issue 2, p.1922-1933
    ADS Link

  9. PLCK G165.7+67.0: Analysis of a Massive Lensing Cluster in a Hubble Space Telescope Census of Submillimeter Giant Arcs Selected Using Planck/Herschel
    Frye, Pascale, Qin, ..., Livermore, et al., 2019,
    The Astrophysical Journal, Volume 871, Issue 1, article id. 51, 21 pp. (2019).
    ADS Link

  10. Heterogeneity and Variability of "Astronomy on Tap" Public Outreach Events
    Rice, Livermore, Silverman, et al., 2019,
    American Astronomical Society, AAS Meeting #233, id.244.05
    ADS Link

  11. The Bright-end Galaxy Candidates at z ̃ 9 from 79 Independent HST Fields
    Morishita, Trenti, Stiavelli, ..., Livermore, et al., 2018,
    The Astrophysical Journal, Volume 867, Issue 2, article id. 150, 18 pp. (2018).
    ADS Link

  12. Texas Spectroscopic Search for Lyα Emission at the End of Reionization I. Constraining the Lyα Equivalent-width Distribution at 6.0 < z < 7.0
    Jung, Finkelstein, Livermore, et al., 2018,
    The Astrophysical Journal, Volume 864, Issue 2, article id. 103, 15 pp. (2018).
    ADS Link

  13. RELICS: A Strong Lens Model for SPT-CLJ0615-5746, a z = 0.972 Cluster
    Paterno-Mahler, Sharon, Coe, ..., Livermore, et al., 2018,
    The Astrophysical Journal, Volume 863, Issue 2, article id. 154, 11 pp. (2018).
    ADS Link

  14. RELICS: Strong Lensing Analysis of the Galaxy Clusters Abell S295, Abell 697, MACS J0025.4-1222, and MACS J0159.8-0849
    Cibirka, Acebron, Zitrin, ..., Livermore, et al., 2018,
    The Astrophysical Journal, Volume 863, Issue 2, article id. 145, 25 pp. (2018).
    ADS Link

  15. HST Follow-up Observations of Two Bright z ̃ 8 Candidate Galaxies from the BoRG Pure-parallel Survey
    Livermore, Trenti, Bradley, et al., 2018,
    The Astrophysical Journal Letters, Volume 861, Issue 2, article id. L17, 5 pp. (2018).
    ADS Link

  16. RELICS: Strong-lensing Analysis of the Massive Clusters MACS J0308.9+2645 and PLCK G171.9-40.7
    Acebron, Cibirka, Zitrin, ..., Livermore, et al., 2018,
    The Astrophysical Journal, Volume 858, Issue 1, article id. 42, 13 pp. (2018).
    ADS Link

  17. RELICS: Reionization Lensing Cluster Survey - Discovering Brightly Lensed Distant Galaxies for JWST
    Coe, Bradley, Salmon, ..., Livermore, et al., 2018,
    American Astronomical Society, AAS Meeting #231, id. 454.10
    ADS Link

  18. Tackling The Dragon: Investigating Lensed Galaxy Structure
    Fortenberry, Livermore, 2018,
    American Astronomical Society, AAS Meeting #231, id. 153.24
    ADS Link

  19. The Faint End of the Lyman Alpha Luminosity Function at 2 < z < 3.8
    Devarakonda, Livermore, Indahl, et al., 2018,
    American Astronomical Society, AAS Meeting #231, id. 149.25
    ADS Link

  20. VizieR Online Data Catalog: Galaxies >~6 from the Hubble Frontier Fields (Livermore+, 2017)
    Livermore, Finkelstein, Lotz, 2017,
    VizieR On-line Data Catalog: J/ApJ/835/113. Originally published in: 2017ApJ...835..113L
    ADS Link

  21. Star Formation at z = 2.481 in the Lensed Galaxy SDSS J1110+6459: Star Formation Down to 30 pc Scales
    Johnson, Rigby, Sharon, ..., Livermore, et al., 2017,
    The Astrophysical Journal Letters, Volume 843, Issue 2, article id. L21, 5 pp. (2017).
    ADS Link

  22. A Magnified View of the Epoch of Reionization with the Hubble Frontier Fields
    Livermore, Finkelstein, Lotz, 2017,
    American Astronomical Society, AAS Meeting #230, id.316.10
    ADS Link

  23. Constraining the End of Reionization with Deep Lyman-alpha Spectroscopy
    Jung, Finkelstein, Livermore, et al., 2017,
    American Astronomical Society, AAS Meeting #230, id.316.08
    ADS Link

  24. JWST Medium-Deep Fields - Windhorst IDS GTO Program
    Windhorst, Alpaslan, Ashcraft, ..., Livermore, et al., 2017,
    JWST Proposal. Cycle 1, ID. #1176
    ADS Link

  25. Directly Observing the Galaxies Likely Responsible for Reionization
    Livermore, Finkelstein, Lotz, 2017,
    The Astrophysical Journal, Volume 835, Issue 2, article id. 113, 21 pp. (2017).
    ADS Link

  26. The minimum halo mass for star formation at z = 6-8
    Finlator, Prescott, Oppenheimer, ..., Livermore, et al., 2017,
    Monthly Notices of the Royal Astronomical Society, Volume 464, Issue 2, p.1633-1639
    ADS Link

  27. Constraining Metallicity and Age for Massive Quiescent Galaxies in a Redshift Range of 1
    Estrada-Carpenter, Papovich, Momcheva, ..., Livermore, et al., 2017,
    American Astronomical Society, AAS Meeting #229, id.347.25
    ADS Link

  28. First Simultaneous Detection of Lyman-alpha Emission and Lyman Break from a Galaxy at Redshift 7.51 from Faint Infrared Grism Survey (FIGS)
    Tilvi, Pirzkal, Malhotra, ..., Livermore, et al., 2017,
    American Astronomical Society, AAS Meeting #229, id.347.08
    ADS Link

  29. A New Semi-Empirical Model of Reionization
    Finkelstein, Paardekooper, Behroozi, ..., Livermore, 2017,
    American Astronomical Society, AAS Meeting #229, id.347.04
    ADS Link

  30. The Expanding Universe of Astronomy on Tap
    Livermore, Morris, Narayan, et al., 2017,
    American Astronomical Society, AAS Meeting #229, id.335.11
    ADS Link

  31. The UV Luminosity Function at 6 < z < 10 from the Hubble Frontier Fields
    Livermore, Finkelstein, Lotz, 2017,
    American Astronomical Society, AAS Meeting #229, id.141.09
    ADS Link

  32. ALMA Reveals Large Molecular Gas Reservoirs in Ancestors of Milky Way-Mass Galaxies at z=1.2-1.3
    Papovich, Labbe, Glazebrook, ..., Livermore, et al., 2017,
    American Astronomical Society, AAS Meeting #229, id.132.01
    ADS Link

  33. Large molecular gas reservoirs in ancestors of Milky Way-mass galaxies nine billion years ago
    Papovich, Labbé, Glazebrook, ..., Livermore, et al., 2016,
    Nature Astronomy, Volume 1, id. 0003 (2016).
    ADS Link

  34. First Results from the Faint Infrared Grism Survey (FIGS): First Simultaneous Detection of Lyα Emission and Lyman Break from a Galaxy at z = 7.51
    Tilvi, Pirzkal, Malhotra, ..., Livermore, et al., 2016,
    The Astrophysical Journal Letters, Volume 827, Issue 1, article id. L14, 6 pp. (2016).
    ADS Link

  35. Keck/MOSFIRE Spectroscopy of z = 7-8 Galaxies: Lyα Emission from a Galaxy at z = 7.66
    Song, Finkelstein, Livermore, et al., 2016,
    The Astrophysical Journal, Volume 826, Issue 2, article id. 113, 9 pp. (2016).
    ADS Link

  36. Caught in the Act: Gas and Stellar Velocity Dispersions in a Fast Quenching Compact Star-Forming Galaxy at z~1.7
    Barro, Faber, Dekel, ..., Livermore, et al., 2016,
    The Astrophysical Journal, Volume 820, Issue 2, article id. 120, 16 pp. (2016).
    ADS Link

  37. VizieR Online Data Catalog: HST Frontier Fields clusters (Richard+, 2014)
    Richard, Jauzac, Limousin, ..., Livermore, et al., 2016,
    VizieR On-line Data Catalog: J/MNRAS/444/268. Originally published in: 2014MNRAS.444..268R
    ADS Link

  38. Pushing the Frontiers: uncovering the earliest galaxies in the Hubble Frontier Fields
    Livermore, 2016,
    Astronomy in Focus, as presented at the IAU XXIX General Assembly, 2015. Proceedings of the IAU, Volume 29B, 2016, pp. 812-815
    ADS Link

  39. A Sneak Peek at the JWST Era: Observing Galaxies Below the Hubble Limit with Gravitational Lensing
    Livermore, 2016,
    American Astronomical Society, AAS Meeting #227, id.342.53
    ADS Link

  40. Expanding the Universe of "Astronomy on Tap" Public Outreach Events
    Rice, Levine, Livermore, et al., 2016,
    American Astronomical Society, AAS Meeting #227, id.248.02
    ADS Link

  41. Searching for faint high-z galaxies in the Hubble Frontier Fields
    Livermore, 2015,
    HST Proposal id.14300. Cycle 23
    ADS Link

  42. The Evolution of the Galaxy Rest-frame Ultraviolet Luminosity Function over the First Two Billion Years
    Finkelstein, Ryan, Papovich, ..., Livermore, et al., 2015,
    The Astrophysical Journal, Volume 810, Issue 1, article id. 71, 35 pp. (2015).
    ADS Link

  43. Astronomy on Tap: science engagement in the pub
    Livermore, Silverman, 2015,
    IAU General Assembly, Meeting #29, id.2257428
    ADS Link

  44. Galaxies in the Epoch of Reionization
    Livermore, 2015,
    IAU General Assembly, Meeting #29, id.2257245
    ADS Link

  45. Pushing the Frontiers: uncovering the earliest galaxies in the Hubble Frontier Fields
    Livermore, 2015,
    IAU General Assembly, Meeting #29, id.2257202
    ADS Link

  46. Probing Bursty Star Formation in Faint Galaxies with the Hubble Frontier Fields
    Finkelstein, Livermore, Song, 2015,
    IAU General Assembly, Meeting #29, id.2247292
    ADS Link

  47. Resolved spectroscopy of gravitationally lensed galaxies: global dynamics and star-forming clumps on ∼100 pc scales at 1 < z < 4
    Livermore, Jones, Richard, et al., 2015,
    Monthly Notices of the Royal Astronomical Society, Volume 450, Issue 2, p.1812-1835
    ADS Link

  48. Searching the Sky for the Brightest Galaxies in the Distant Universe
    Finkelstein, Diekmann, Finkelstein, ..., Livermore, 2014,
    Spitzer Proposal ID 11121
    ADS Link

  49. Keck-I MOSFIRE Spectroscopy of Compact Star-forming Galaxies at z >~ 2: High Velocity Dispersions in Progenitors of Compact Quiescent Galaxies
    Barro, Trump, Koo, ..., Livermore, et al., 2014,
    The Astrophysical Journal, Volume 795, Issue 2, article id. 145, 12 pp. (2014).
    ADS Link

  50. Mass and magnification maps for the Hubble Space Telescope Frontier Fields clusters: implications for high-redshift studies
    Richard, Jauzac, Limousin, ..., Livermore, et al., 2014,
    Monthly Notices of the Royal Astronomical Society, Volume 444, Issue 1, p.268-289
    ADS Link

  51. Galaxies in the epoch of reionization
    Livermore, 2014,
    Keck Observatory Archive DEIMOS, id.N168D
    ADS Link

  52. The HETDEX Pilot Survey. V. The Physical Origin of Lyα Emitters Probed by Near-infrared Spectroscopy
    Song, Finkelstein, Gebhardt, ..., Livermore, et al., 2014,
    The Astrophysical Journal, Volume 791, Issue 1, article id. 3, 24 pp. (2014).
    ADS Link

  53. Completing the Galaxy Census from z=0 to z~7 in the CANDELS/COSMOS Field
    Tilvi, Papovich, Finkelstein, ..., Livermore, et al., 2014,
    NOAO Proposal ID 2014A-0236
    ADS Link

  54. Galaxies Under the Cosmic Microscope
    Livermore, 2014,
    American Astronomical Society, AAS Meeting #223, id.133.05
    ADS Link

  55. Harnessing the Power of Gravitational Lensing: Resolved Star Formation at 1 < z < 5
    Livermore, 2013,
    PhD Thesis, Durham University, 2013
    ADS Link

  56. High-resolution Study of the Cluster Complexes in a Lensed Spiral at Redshift 1.5: Constraints on the Bulge Formation and Disk Evolution
    Adamo, Östlin, Bastian, ..., Livermore, et al., 2013,
    The Astrophysical Journal, Volume 766, Issue 2, article id. 105, 16 pp. (2013).
    ADS Link

  57. Hubble Space Telescope Hα imaging of star-forming galaxies at z ≃ 1-1.5: evolution in the size and luminosity of giant H II regions
    Livermore, Jones, Richard, et al., 2012,
    Monthly Notices of the Royal Astronomical Society, Volume 427, Issue 1, pp. 688-702.
    ADS Link

  58. Observational Limits on the Gas Mass of a z = 4.9 Galaxy
    Livermore, Swinbank, Smail, et al., 2012,
    The Astrophysical Journal Letters, Volume 758, Issue 2, article id. L35, 5 pp. (2012).
    ADS Link

  59. The emission line properties of gravitationally lensed 1.5 < z < 5 galaxies
    Richard, Jones, Ellis, ..., Livermore, et al., 2011,
    Monthly Notices of the Royal Astronomical Society, Volume 413, Issue 1, pp. 643-658.
    ADS Link

  60. Metallicity Gradient of a Lensed Face-on Spiral Galaxy at Redshift 1.49
    Yuan, Kewley, Swinbank, ..., Livermore, 2011,
    The Astrophysical Journal Letters, Volume 732, Issue 1, article id. L14, 5 pp. (2011).
    ADS Link