Dr Guillaume Mahler's Outputs (48)

Strong-lensing Analysis of SPT-CL J2325−4111 and SPT-CL J0049−2440, Two Powerful Cosmic Telescopes ( R E > 40″) from the SPT Clusters Sample (2025)
Journal Article
Mahler, G., Sharon, K., Bayliss, M., Bleem, L. E., Brodwin, M., Floyd, B., Gassis, R., Gladders, M. D., Khullar, G., Remolina González, J. D., & Sarkar, A. (2025). Strong-lensing Analysis of SPT-CL J2325−4111 and SPT-CL J0049−2440, Two Powerful Cosmic Telescopes ( R E > 40″) from the SPT Clusters Sample. The Astrophysical Journal, 980(1), Article 48. https://doi.org/10.3847/1538-4357/ad9aa5

We report the results from a study of two massive (M500c > 6.0 × 1014 M⊙) strong-lensing clusters selected from the South Pole Telescope cluster survey for their large Einstein radius (RE > 40″), SPT-CL J2325−4111 and SPT-CL J0049−2440. Ground-based... Read More about Strong-lensing Analysis of SPT-CL J2325−4111 and SPT-CL J0049−2440, Two Powerful Cosmic Telescopes ( R E > 40″) from the SPT Clusters Sample.

Connecting Lyα and Ionizing Photon Escape in the Sunburst Arc (2024)
Journal Article
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 Lyα and Ionizing Photon Escape in the Sunburst Arc. Astrophysical Journal, 977(2), Article 234. https://doi.org/10.3847/1538-4357/ad9247

We investigate the Lyα and Lyman continuum (LyC) properties of the Sunburst Arc, a z = 2.37 gravitationally lensed galaxy with a multiply imaged, compact region leaking LyC and a triple-peaked Lyα profile indicating direct Lyα escape. Non-LyC-leaking... Read More about Connecting Lyα and Ionizing Photon Escape in the Sunburst Arc.

ALMA Lensing Cluster Survey: Deep 1.2 mm Number Counts and Infrared Luminosity Functions at z ≃ 1–8 (2024)
Journal Article
Fujimoto, S., Kohno, K., Ouchi, M., Oguri, M., Kokorev, V., Brammer, G., Sun, F., González-López, J., Bauer, F. E., Caminha, G. B., Hatsukade, B., Richard, J., Smail, I., Tsujita, A., Ueda, Y., Uematsu, R., Zitrin, A., Coe, D., Kneib, J.-P., Postman, M., …Wang, W.-H. (2024). ALMA Lensing Cluster Survey: Deep 1.2 mm Number Counts and Infrared Luminosity Functions at z ≃ 1–8. Astrophysical Journal Supplement, 275(2), Article 36. https://doi.org/10.3847/1538-4365/ad5ae2

We present a statistical study of 180 dust continuum sources identified in 33 massive cluster fields by the Atacama Large Millimeter/submillimeter Array Lensing Cluster Survey (ALCS) over a total of 133 arcmin2 area, homogeneously observed at 1.2 mm.... Read More about ALMA Lensing Cluster Survey: Deep 1.2 mm Number Counts and Infrared Luminosity Functions at z ≃ 1–8.

Efficient Point-spread Function Modeling with ShOpt.jl: A Point-spread Function Benchmarking Study with JWST NIRCam Imaging (2024)
Journal Article
Berman, E. M., McCleary, J. E., Koekemoer, A. M., Franco, M., Drakos, N. E., Liu, D., Nightingale, J. W., Shuntov, M., Scognamiglio, D., Massey, R., Mahler, G., McCracken, H. J., Robertson, B. E., Faisst, A. L., Casey, C. M., & Kartaltepe, J. S. (2024). Efficient Point-spread Function Modeling with ShOpt.jl: A Point-spread Function Benchmarking Study with JWST NIRCam Imaging. Astronomical Journal, 168(4), Article 174. https://doi.org/10.3847/1538-3881/ad6a0f

With their high angular resolutions of 30–100 mas, large fields of view, and complex optical systems, imagers on next-generation optical/near-infrared space observatories, such as the Near-Infrared Camera (NIRCam) on the James Webb Space Telescope, p... Read More about Efficient Point-spread Function Modeling with ShOpt.jl: A Point-spread Function Benchmarking Study with JWST NIRCam Imaging.

Unveiling the Distant Universe: Characterizing z ≥ 9 Galaxies in the First Epoch of COSMOS-Web (2024)
Journal Article
Franco, M., Akins, H. B., Casey, C. M., Finkelstein, S. L., Shuntov, M., Chworowsky, K., Faisst, A. L., Fujimoto, S., Ilbert, O., Koekemoer, A. M., Liu, D., Lovell, C. C., Maraston, C., McCracken, H. J., McKinney, J., Robertson, B. E., Bagley, M. B., Champagne, J. B., Cooper, O. R., Ding, X., …Zavala, J. A. (2024). Unveiling the Distant Universe: Characterizing z ≥ 9 Galaxies in the First Epoch of COSMOS-Web. The Astrophysical Journal, 973(1), Article 23. https://doi.org/10.3847/1538-4357/ad5e6a

We report the identification of 15 galaxy candidates at z ≥ 9 using the initial COSMOS-Web JWST observations over 77 arcmin2 through four Near Infrared Camera filters (F115W, F150W, F277W, and F444W) with an overlap with the Mid-Infrared Imager (F770... Read More about Unveiling the Distant Universe: Characterizing z ≥ 9 Galaxies in the First Epoch of COSMOS-Web.

The KALEIDOSCOPE survey : A new strong and weak gravitational lensing view of the massive galaxy cluster MACS J1423.8+2404 (2024)
Journal Article
Patel, N. R., Jauzac, M., Niemiec, A., Lagattuta, D., Mahler, G., Beauchesne, B., Edge, A., Ebeling, H., & Limousin, M. (2024). The KALEIDOSCOPE survey : A new strong and weak gravitational lensing view of the massive galaxy cluster MACS J1423.8+2404. Monthly Notices of the Royal Astronomical Society, 533(4), 4500-4514. https://doi.org/10.1093/mnras/stae2069

We present a combined strong and weak gravitational-lensing analysis of the massive galaxy cluster MACS J1423.8+2404 (z = 0.545, MACS J1423 hereafter), one of the most dynamically relaxed and massive cool-core clusters discovered in the MAssive Clust... Read More about The KALEIDOSCOPE survey : A new strong and weak gravitational lensing view of the massive galaxy cluster MACS J1423.8+2404.

A complex node of the cosmic web associated with the massive galaxy cluster MACS J0600.1-2008 (2024)
Journal Article
Furtak, L. J., Zitrin, A., Richard, J., Eckert, D., Sayers, J., Ebeling, H., Fujimoto, S., Laporte, N., Lagattuta, D., Limousin, M., Mahler, G., Meena, A. K., Andrade-Santos, F., Frye, B. L., Jauzac, M., Koekemoer, A. M., Kohno, K., Espada, D., Lu, H., Massey, R., & Niemiec, A. (2024). A complex node of the cosmic web associated with the massive galaxy cluster MACS J0600.1-2008. Monthly Notices of the Royal Astronomical Society, 533(2), 2242-2261. https://doi.org/10.1093/mnras/stae1943

The Galaxy–Galaxy Strong Lensing Cross Section and the Internal Distribution of Matter in ΛCDM Substructure (2024)
Journal Article
Tokayer, Y. M., Dutra, I., Natarajan, P., Mahler, G., Jauzac, M., & Meneghetti, M. (2024). The Galaxy–Galaxy Strong Lensing Cross Section and the Internal Distribution of Matter in ΛCDM Substructure. The Astrophysical Journal, 970(2), Article 143. https://doi.org/10.3847/1538-4357/ad51fd

Strong gravitational lensing offers a powerful probe of the detailed distribution of matter in lenses, while magnifying and bringing faint background sources into view. Observed strong lensing by massive galaxy clusters, which are often in complex dy... Read More about The Galaxy–Galaxy Strong Lensing Cross Section and the Internal Distribution of Matter in ΛCDM Substructure.

Self-consistent Combined HST, K -band, and Spitzer Photometric Catalogs of the BUFFALO Survey Fields (2024)
Journal Article
Pagul, A., Sánchez, F. J., Davidzon, I., Koekemoer, A. M., Mobasher, B., Jauzac, M., Steinhardt, C. L., Atek, H., Cen, R., Chemerynska, I., Furtak, L. J., Lagattuta, D. J., Mahler, G., Montes, M., Nonino, M., Sharon, K., & Weaver, J. R. (2024). Self-consistent Combined HST, K -band, and Spitzer Photometric Catalogs of the BUFFALO Survey Fields. Astrophysical Journal Supplement, 273(1), Article 10. https://doi.org/10.3847/1538-4365/ad40a1

This article presents new astronomical source catalogs using data from the BUFFALO Survey. These catalogs contain detailed information for over 100,000 astronomical sources in the six BUFFALO clusters: A370, A2744, AS1063, MACS 0416, MACS 0717, and M... Read More about Self-consistent Combined HST, K -band, and Spitzer Photometric Catalogs of the BUFFALO Survey Fields.

The COSMOS-Web ring: In-depth characterization of an Einstein ring lensing system at z ∼ 2 (2024)
Journal Article
Mercier, W., Shuntov, M., Gavazzi, R., Nightingale, J. W., Arango, R., Ilbert, O., Amvrosiadis, A., Ciesla, L., Casey, C. M., Jin, S., Faisst, A. L., Andika, I. T., Drakos, N. E., Enia, A., Franco, M., Gillman, S., Gozaliasl, G., Hayward, C. C., Huertas-Company, M., Kartaltepe, J. S., …Vijayan, A. P. (2024). The COSMOS-Web ring: In-depth characterization of an Einstein ring lensing system at z ∼ 2. Astronomy & Astrophysics, 687, Article A61. https://doi.org/10.1051/0004-6361/202348095

Aims. We provide an in-depth analysis of the COSMOS-Web ring, an Einstein ring at z ≈ 2 that we serendipitously discovered during the data reduction of the COSMOS-Web survey and that could be the most distant lens discovered to date.

Methods. We e... Read More about The COSMOS-Web ring: In-depth characterization of an Einstein ring lensing system at z ∼ 2.

Bound star clusters observed in a lensed galaxy 460 Myr after the Big Bang (2024)
Journal Article
Adamo, A., Bradley, L. D., Vanzella, E., Claeyssens, A., Welch, B., Diego, J. M., Mahler, G., Oguri, M., Sharon, K., Abdurro’uf, Hsiao, T. Y.-Y., Xu, X., Messa, M., Lassen, A. E., Zackrisson, E., Brammer, G., Coe, D., Kokorev, V., Ricotti, M., Zitrin, A., …Tamura, Y. (2024). Bound star clusters observed in a lensed galaxy 460 Myr after the Big Bang. Nature, 632(8025), 513-516. https://doi.org/10.1038/s41586-024-07703-7

The Cosmic Gems arc is among the brightest and highly magnified galaxies observed at redshift z ≈ 10.2 (ref. 1). However, it is an intrinsically ultraviolet faint galaxy, in the range of those now thought to drive the reionization of the Universe2–4.... Read More about Bound star clusters observed in a lensed galaxy 460 Myr after the Big Bang.

Strong gravitational lensing’s ‘external shear’ is not shear (2024)
Journal Article
Etherington, A., Nightingale, J., Massey, R., Tam, S.-I., Cao, X., Niemiec, A., He, Q., Robertson, A., Li, R., Amvrosiadis, A., Cole, S., Diego, J., Frenk, C., Frye, B., Harvey, D., Jauzac, M., Koekemoer, A., Lagattuta, D., Lange, S., Limousin, M., …Steinhardt, C. (2024). Strong gravitational lensing’s ‘external shear’ is not shear. Monthly Notices of the Royal Astronomical Society, 531(3), 3684-3697. https://doi.org/10.1093/mnras/stae1375

The distribution of mass in galaxy-scale strong gravitational lenses is often modelled as an elliptical power-law plus ‘external shear’, which notionally accounts for neighbouring galaxies and cosmic shear along our line of sight. A small amount of e... Read More about Strong gravitational lensing’s ‘external shear’ is not shear.

TEMPLATES: Characterization of a Merger in the Dusty Lensing SPT0418–47 System (2024)
Journal Article
Cathey, J., Gonzalez, A. H., Lower, S., Phadke, K. A., Spilker, J., Aravena, M., …Vizgan, D. (2024). TEMPLATES: Characterization of a Merger in the Dusty Lensing SPT0418–47 System. Astrophysical Journal, 967(1), Article 11. https://doi.org/10.3847/1538-4357/ad33c9

We present JWST and Atacama Large Millimeter/submillimeter Array (ALMA) imaging for the lensing system SPT0418−47, which includes a strongly lensed, dusty, star-forming galaxy at redshift z = 4.225 and an associated multiply imaged companion. The JWS... Read More about TEMPLATES: Characterization of a Merger in the Dusty Lensing SPT0418–47 System.

COOL-LAMPS. VI. Lens Model and New Constraints on the Properties of COOL J1241+2219, a Bright z = 5 Lyman Break Galaxy and its z = 1 Cluster Lens (2024)
Journal Article
Klein, M., Sharon, K., Napier, K., Gladders, M. D., Khullar, G., Bayliss, M., Dahle, H., Owens, M. R., Stark, A., Brownsberger, S., Kim, K. J., Kuchta, N., Mahler, G., Smith, G., Walker, R., Gozman, K., Martinez, M. N., Matthews Acuña, O. S., Merz, K., Sanchez, J. A., …Tavangar, K. (2024). COOL-LAMPS. VI. Lens Model and New Constraints on the Properties of COOL J1241+2219, a Bright z = 5 Lyman Break Galaxy and its z = 1 Cluster Lens. Astrophysical Journal, 963(1), Article 44. https://doi.org/10.3847/1538-4357/ad22de

We present a strong lensing analysis of COOL J1241+2219, the brightest known gravitationally lensed galaxy at z ≥ 5, based on new multiband Hubble Space Telescope (HST) imaging data. The lensed galaxy has a redshift of z = 5.043, placing it shortly a... Read More about COOL-LAMPS. VI. Lens Model and New Constraints on the Properties of COOL J1241+2219, a Bright z = 5 Lyman Break Galaxy and its z = 1 Cluster Lens.

BUFFALO/Flashlights: Constraints on the abundance of lensed supergiant stars in the Spock galaxy at redshift 1 (2024)
Journal Article
Diego, J. M., Li, S. K., Meena, A. K., Niemiec, A., Acebron, A., Jauzac, M., …Pascale, M. (2024). BUFFALO/Flashlights: Constraints on the abundance of lensed supergiant stars in the Spock galaxy at redshift 1. Astronomy & Astrophysics, 681, Article A124. https://doi.org/10.1051/0004-6361/202346761

In this work, we present a constraint on the abundance of supergiant (SG) stars at redshift z ≈ 1, based on recent observations of a
strongly lensed arc at this redshift. First we derived a free-form model of MACS J0416.1-2403 using data from the Be... Read More about BUFFALO/Flashlights: Constraints on the abundance of lensed supergiant stars in the Spock galaxy at redshift 1.

The Extended [C ii] under Construction? Observation of the Brightest High-z Lensed Star-forming Galaxy at z = 6.2 (2024)
Journal Article
Fudamoto, Y., Inoue, A. K., Coe, D., Welch, B., Acebron, A., Ricotti, M., …Zitrin, A. (2024). The Extended [C ii] under Construction? Observation of the Brightest High-z Lensed Star-forming Galaxy at z = 6.2. Astrophysical Journal, 961(1), Article 71. https://doi.org/10.3847/1538-4357/ad0f95

We present results of [C ii] 158 μm emission line observations, and report the spectroscopic redshift confirmation of a strongly lensed (μ ∼ 20) star-forming galaxy, MACS0308-zD1 at z = 6.2078 ± 0.0002. The [C ii] emission line is detected with a sig... Read More about The Extended [C ii] under Construction? Observation of the Brightest High-z Lensed Star-forming Galaxy at z = 6.2.

A full reconstruction of two galaxy clusters intra-cluster medium with strong gravitational lensing (2024)
Journal Article
Allingham, J. F. V., Bœhm, C., Eckert, D., Jauzac, M., Lagattuta, D., Mahler, G., …Ettori, S. (2024). A full reconstruction of two galaxy clusters intra-cluster medium with strong gravitational lensing. Monthly Notices of the Royal Astronomical Society, 528(2), 1711-1736. https://doi.org/10.1093/mnras/stae107

Whilst X-rays and Sunyaev–Zel’dovich observations allow to study the properties of the intra-cluster medium (ICM) of galaxy clusters, their gravitational potential may be constrained using strong gravitational lensing. Although being physically relat... Read More about A full reconstruction of two galaxy clusters intra-cluster medium with strong gravitational lensing.

JWST/NIRCam Probes Young Star Clusters in the Reionization Era Sunrise Arc (2023)
Journal Article
Vanzella, E., Claeyssens, A., Welch, B., Adamo, A., Coe, D., Diego, J. M., Mahler, G., Khullar, G., Kokorev, V., Oguri, M., Ravindranath, S., Furtak, L. J., Hsiao, T. Y.-Y., Abdurro'uf, Mandelker, N., Brammer, G., Bradley, L. D., Bradač, M., Conselice, C. J., Dayal, P., …Norman, C. (2023). JWST/NIRCam Probes Young Star Clusters in the Reionization Era Sunrise Arc. Astrophysical Journal, 945(1), Article 53. https://doi.org/10.3847/1538-4357/acb59a

Star cluster formation in the early universe and its contribution to reionization remains largely unconstrained to date. Here we present JWST/NIRCam imaging of the most highly magnified galaxy known at z ∼ 6, the Sunrise arc. We identify six young ma... Read More about JWST/NIRCam Probes Young Star Clusters in the Reionization Era Sunrise Arc.

Hubble Constant Measurement from Three Large-separation Quasars Strongly Lensed by Galaxy Clusters (2023)
Journal Article
Napier, K., Sharon, K., Dahle, H., Bayliss, M., Gladders, M. D., Mahler, G., …Florian, M. (2023). Hubble Constant Measurement from Three Large-separation Quasars Strongly Lensed by Galaxy Clusters. Astrophysical Journal, 959(2), Article 134. https://doi.org/10.3847/1538-4357/ad045a

Tension between cosmic microwave background–based and distance ladder–based determinations of the Hubble constant H 0 motivates the pursuit of independent methods that are not subject to the same systematic effects. A promising alternative, proposed... Read More about Hubble Constant Measurement from Three Large-separation Quasars Strongly Lensed by Galaxy Clusters.

Exploring the correlation between dark matter, intracluster light, and globular cluster distribution in SMACS0723 (2023)
Journal Article
Diego, J. M., Pascale, M., Frye, B., Zitrin, A., Broadhurst, T., Mahler, G., …Montes, M. (2023). Exploring the correlation between dark matter, intracluster light, and globular cluster distribution in SMACS0723. Astronomy & Astrophysics, 679, Article A159. https://doi.org/10.1051/0004-6361/202345868

We present a free-form model of SMACS0723, the first cluster observed with JWST. This model does not make any strong assumptions on the distribution of mass (mostly made up of dark matter) in the cluster and we use it to study the possible correlatio... Read More about Exploring the correlation between dark matter, intracluster light, and globular cluster distribution in SMACS0723.