Alexander Navarre

Alexander Navarre

Scientifically Rigorous Data Scientist & Astrophysics PhD

Publications

You can also find my articles on my Google Scholar profile.

Journal Articles

Connecting Lyα and Ionizing Photon Escape in the Sunburst Arc

Published in The Astrophysical Journal, 2024

This paper is a study of the Lyman-Continuum (LyC) and Lyman-Alpha (Lya) emission of the Sunburst Arc: one of the brightest-known gravitationally-lensed galaxies. Strong correlations are found between the LyC escape fraction and mulitple Lya measures such as peak separation and equivalent width. A possible complex geometry of neutral hydrogen is proposed to explain the differences in the Lya/LyC spectra across the sunburst arc. The study underscores the importance of resolving small physical scales to reliably explain Lya and LyC escape.

Recommended citation: Owens, M. R., Kim, K. J., Bayliss, M. B., Rivera-Thorsen, T. E., Sharon, K., Rigby, J. R., Navarre, A., Florian, M., Gladders, M. D., Burns, J. G., Khullar, G., Chisholm, J., Mahler, G., Dahle, H., Malhas, C. M., Welch, B., Hutchison, T. A., Gassis, R., Choe, S., & Adhikari, P. (2024). Connecting Ly\ensuremathα and Ionizing Photon Escape in the Sunburst Arc. \apj, 977(2), e234. https://doi.org/10.3847/1538-4357/ad9247
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TEMPLATES: Characterization of a Merger in the Dusty Lensing SPT0418–47 System

Published in The Astrophysical Journal, 2024

This paper uses JWST and AMLA to characterize the gravitational-lensing system SPT0418-47, which includes a lensed image of a dusty, star-forming galaxy and an associated companion. The calculated physical separations, redshifts, and evidence of tidal features indicate that these galaxies are interacting. Interestingly, the star-formation rates and stellar masses of both galaxies indicate that their interaction has not noticibly elevated the star-formation level.

Recommended citation: Cathey, J., Gonzalez, A. H., Lower, S., Phadke, K. A., Spilker, J., Aravena, M., Bayliss, M., Birkin, J. E., Birrer, S., Chapman, S., Dahle, H., Hayward, C. C., Hezaveh, Y., Hill, R., Hutchison, T. A., Kim, K. J., Mahler, G., Marrone, D. P., Narayanan, D., … Vizgan, D. (2024). TEMPLATES: Characterization of a Merger in the Dusty Lensing SPT0418–47 System. \apj, 967(1), e11. https://doi.org/10.3847/1538-4357/ad33c9
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Resolving Clumpy versus Extended Lyα in Strongly Lensed, High-redshift Lyα Emitters

Published in The Astrophysical Journal, 2024

This paper studies a set of six strongly-lensed Lyman-Alpha emitting galaxies (LAEs) at redshifts ~ 4-5. Through the analysis of Hubble Space Telescope and Spitzer Space Telescope imaging, this paper calculates esimates of the stellar masses, stellar population ages, and amounts of dust. These properties are consistent with young stellar populations that create Lyman-Alpha. Narrowband Lyman-Alpha imaging indicates these galaxies are non-interacting (not merging galaxies). The paper finds two broad camps of Lyman-Alpha spatial distributions, clumpy and extended. A suggestive trend is found in that the youngest stellar populations in the sample are clumpy while the older populations are extended.

Recommended citation: Navarre, A., Khullar, G., Bayliss, M. B., Dahle, H., Florian, M., Gladders, M., Kim, K. J., Owens, M. R., Rigby, J., Roberson, J., Sharon, K., Shibuya, T., & Walker, R. (2024). Resolving Clumpy versus Extended Ly\ensuremathα in Strongly Lensed, High-redshift Ly\ensuremathα Emitters. \apj, 962(2), e175. https://doi.org/10.3847/1538-4357/ad10ad
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Small Region, Big Impact: Highly Anisotropic Lyman-continuum Escape from a Compact Starburst Region with Extreme Physical Properties

Published in The Astrophysical Journal Letters, 2023

This paper studies a small region of The Sunburst Arc, one of the brightest-known gravitationally-lensed galaxies. The small region uniquely has high Lyman-Continuum (LyC, ionizing radiation) escape: a critical component to understanding star-formation based Reionization models. Spatially resolved analysis characterizes the region as being consistent with approximately “pure” stellar light. This provides evidence for pencil-beam LyC escape: where anisotropic processes “poke” ionized channels through the surrounding gas, letting radiation escape reletively unimpeded.

Recommended citation: Kim, K. J., Bayliss, M. B., Rigby, J. R., Gladders, M. D., Chisholm, J., Sharon, K., Dahle, H., Rivera-Thorsen, T. E., Florian, M. K., Khullar, G., Mahler, G., Mainali, R., Napier, K. A., Navarre, A., Owens, M. R., & Roberson, J. (2023). Small Region, Big Impact: Highly Anisotropic Lyman-continuum Escape from a Compact Starburst Region with Extreme Physical Properties. \apjl, 955(1), eL17. https://doi.org/10.3847/2041-8213/acf0c5
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Spatial variations in aromatic hydrocarbon emission in a dust-rich galaxy

Published in Nature, 2023

This paper studies Polycyclic Aromatic Hydrocarbons (PAHs): large orangic molecules that trace the dust that regulares interstellar gas cooling. With the launch of JWST, our ability to resolve infrared galaxy features at high redshift (in the early universe) is highly increased. This paper presents spatially-resolved PAH spectral features. It finds order-of-magnitude variations in the PAH feature strength across the galaxy, suggesting either physical offsets in the PAH distribution or wide variations in the local ultraviolet radiatino field.

Recommended citation: Spilker, J. S., Phadke, K. A., Aravena, M., Archipley, M., Bayliss, M. B., Birkin, J. E., Béthermin, M., Burgoyne, J., Cathey, J., Chapman, S. C., Dahle, H., Gonzalez, A. H., Gururajan, G., Hayward, C. C., Hezaveh, Y. D., Hill, R., Hutchison, T. A., Kim, K. J., Kim, S., … Whitaker, K. E. (2023). Spatial variations in aromatic hydrocarbon emission in a dust-rich galaxy. \nat, 618(7966), 708–711. https://doi.org/10.1038/s41586-023-05998-6
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The Cosmic Telescope that Lenses the Sunburst Arc, PSZ1 G311.65-18.48: Strong Gravitational Lensing model and Source Plane Analysis

Published in The Astrophysical Journal, 2022

This paper is a gravitational lensing analysis of the galaxy cluster PSZ1 G311.65-18.48. This cluster lenses the one of the brightest-known lensed galaxies: The Sunburst Arc. The Sunburst Arc, as well as 14 additional lensed galaxies in the field, are identified and characterized to constrain the lensing model. Additionally, the paper argues that an unusual clump of light in the Sunburst Arc is not a transient event.

Recommended citation: Sharon, K., Mahler, G., Rivera-Thorsen, T. E., Dahle, H., Gladders, M. D., Bayliss, M. B., Florian, M. K., Kim, K. J., Khullar, G., Mainali, R., Napier, K. A., Navarre, A., Rigby, J. R., Remolina González, J. D., & Sharma, S. (2022). The Cosmic Telescope That Lenses the Sunburst Arc, PSZ1 G311.65-18.48: Strong Gravitational Lensing Model and Source Plane Analysis. \apj, 941(2), e203. https://doi.org/10.3847/1538-4357/ac927a
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