My research has focused on the study of the large scale structure in the distant universe, and the evolution of massive galaxies over cosmic time. My deep interest in using observations at multiple wavelengths has motivated me to perform studies based on a large amount of data obtained from some of the most important telescopes, such as VLT, ALMA, and LOFAR. My main expertise for analyzing data is related to the measurement of clustering of sources.

The environments of quasars at z~4

During my Ph.D., I studied the environments of 23 quasars at z~4. Using data from the VLT, I quantified the clustering of galaxies (LBGs and LAEs) around quasars. I detected that both LBGs and LAEs are strongly clustered around quasars, and I showed solid evidence supporting the idea that quasars trace overdensities of galaxies in the early universe (García-Vergara et al. 2017, 2019). I recently extended this study to submillimeter wavelengths to detect dusty galaxies that could be missed in the optical survey. I am currently working with recently obtained ALMA observations of these quasar fields to detect galaxies in continuum emission and CO(4-3) emission.

The clustering of submillimeter galaxies detected with ALMA

During my postdoctoral position at Leiden University, I have mostly worked on the measurement of the clustering of submillimeter galaxies (SMGs) detected with ALMA to understand their nature and fate. In a pioneering work, I proposed a method to measure the clustering of ALMA detected sources based on detailed forward modeling of submillimeter observations (García-Vergara et al. 2020). We found that the strength of SMG clustering based on single-dish observations was overestimated and therefore SMGs might be hosted by dark matter halos less massive than has previously been estimated. We conclude that only SMGs with S_870>6 mJy may be connected to massive local elliptical galaxies, quasars at intermediate redshifts and high-redshift star-forming galaxies, whereas fainter SMGs are unlikely linked to these populations.

The dependence of the clustering of radio sources with their physical properties

Currently, I am working with the recently completed LoTSS deep-fields survey performed with the large European radio telescope network LOFAR. I am studying the dependence of the clustering of radio sources with physical properties such as redshift, luminosity, star formation rate (SFR), stellar mass, and BH activity (AGNs/SFGs). These measurements will be used to determine the physical properties of galaxies in different environments and their evolution over time.


 An updated list of my publications can be found here.

[11] "APEX at the QSO MUSEUM: Molecular gas reservoirs associated with z∼3 quasars and their link to the extended Lyα emission"

Muñoz-Elgueta, N., Arrigoni Battaia, F., Kauffmann, G., De Breuck, C., García-Vergara, C., Zanella, A., Farina, E. P., Decarli, R.

2022, Accepted in MNRAS.

[10] "ALMA reveals large overdensity and strong clustering of galaxies in quasar environments at z~4"

García-Vergara, C.J., Rybak, M., Hodge, J., Hennawi, J.H., Decarli, R., González-López, J., Arrigoni-Battaia, F., Aravena, M., Farina, E.P.

2021, Accepted in ApJ.

[9] "The LOFAR Two-metre Sky Survey (LoTSS) V. Second data release"

Shimwell, T. W., et al. (including García-Vergara, C.J.)

2021, Accepted in A&A.

[8] "Low-frequency radio spectra of submillimetre galaxies in the Lockman Hole"

Ramasawmy, J., Geach, J. E., Hardcastle, M. J., Best, P. N., Bonato, M., Bondi, M., Calistro Rivera, G., Cochrane, R. K., Conway, J. E., Coppin, K., Duncan, K. J., Dunlop, J. S., Franco, M., García-Vergara, C., Jarvis, M. J., Kondapally, R., McCheyne, I., Prandoni, I., Röttgering, H. J. A., Smith, D. J. B., Tasse, C., Wang, L.

2021, A&A, 648A, 14R.

[7] "Clustering of submillimeter galaxies detected with ALMA"

García-Vergara, C.J., Hodge, J., Hennawi, J., Wardlow, J. Weiss, A., Myers, A., Hickox, R.

2020, ApJ, 904, 2G.

[6] Proceedings IAU Symposium: "Clustering of galaxies around quasars at z~4"

García-Vergara, C.J., Hennawi J.F., Barrientos, L. F., Arrigoni-Battaia, F.

2020, IAUS, 352, 171G.

[5] "Clustering of Lyman-alpha Emitters Around Quasars at z~4"

García-Vergara, C.J., Hennawi J.F., Barrientos, L. F., Arrigoni-Battaia, F.

2019, ApJ, 886, 79G.

[4] "Spectroscopic characterization of galaxy clusters in RCS-1: spectroscopic confirmation, redshift accuracy, and dynamical mass-richness relation"

Gilbank, D.G., Barrientos, L.F., Ellingson, E., Blindert, K., Yee, H. K. C., Anguita, T., Gladders, M.D., Hall, P.B., Hertling, G., Infante, L., Yan, R., Carrasco, M., García-Vergara, C.J., Dawson, K. S., Lidman, C., Morokuma, T.

2018, MNRAS, 476, 1991G.

[3] "Strong Cross-Correlation Between Luminous Quasars and Lyman Break Galaxies at z~4"

García-Vergara, C.J., Hennawi J.F., Barrientos, L. F., Rix, H-W.

2017, ApJ, 848, 7G.

[2] "VLT/Magellan Spectroscopy of 29 Strong Lensing Selected Galaxy Clusters"

Carrasco, M., Barrientos, L. F., Anguita, T., García-Vergara, C.J., Bayliss, M., Gladders, M., West, M.

2017, ApJ, 834, 210C.

[1] "Microlensing of the broad-line region in the quadruply imaged quasar HE0435-1223"

Braibant, L., Hutsemékers, D., Sluse, D., Anguita, T., García-Vergara, C.J.

2014, A&A, 565L, 11B.


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AstroTwinColo 2020, University of Antioquia, Colombia

The Large scale structure of the universe

AstroTwinColo is an Astronomy Twinning Program between the Leiden Observatory (Netherlands) and the University of Antioquia (Colombia). I was an invited lecturer in 2020 to teach about "The Large scale structure of the universe". Below you will find the slides and the recorded lectures and worskhops.

Lecture1 (slides,video1,video2) --- Workshop1 (Tutorial,video1,video2)

Lecture2 (slides,video1,video2) --- Workshop2 (Tutorial,video1,video2)

Lecture3 (slides,video1,video2) --- Workshop3 (Tutorial,video1,video2)

Lecture4 (slides,video1,video2) --- Workshop4 (Tutorial,video1,video2)

Lecture5 (slides,video1,video2) --- Workshop5 (Tutorial,video1,video2)


Cristina García Vergara

Leiden Observatory

Niels Bohrweg 2, P.O. Box 9513

2300 RA Leiden

The Netherlands

Tel: +31 (0) 71 527 8438

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