The Complex Star Formation History of the Halo of NGC 5128 (Cen A) (2024)
Journal Article
Aghdam, S. T., Javadi, A., Hashemi, S., Abdollahi, M., van Loon, J. T., Khosroshahi, H., Golshan, R. H., Saremi, E., & Saberi, M. (2024). The Complex Star Formation History of the Halo of NGC 5128 (Cen A). Astrophysical Journal, 972(1), Article 47. https://doi.org/10.3847/1538-4357/ad57c0

NGC 5128 (Cen A) is the nearest giant elliptical galaxy and one of the brightest extragalactic radio sources in the sky, boasting a prominent dust lane and jets emanating from its nuclear supermassive black hole. In this paper, we construct the star... Read More about The Complex Star Formation History of the Halo of NGC 5128 (Cen A).

A Galactic Eclipse: The Small Magellanic Cloud Is Forming Stars in Two Superimposed Systems (2024)
Journal Article
Murray, C. E., Hasselquist, S., Peek, J. E. G., Lindberg, C. W., Almeida, A., Choi, Y., Craig, J. E. M., Dénes, H., Dickey, J. M., Di Teodoro, E. M., Federrath, C., Gerrard, I. A., Gibson, S. J., Leahy, D., Lee, M.-Y., Lynn, C., Ma, Y. K., Marchal, A., McClure-Griffiths, N. M., Nidever, D., …van Loon, J. T. (2024). A Galactic Eclipse: The Small Magellanic Cloud Is Forming Stars in Two Superimposed Systems. Astrophysical Journal, 962(2), Article 120. https://doi.org/10.3847/1538-4357/ad1591

The structure and dynamics of the star-forming disk of the Small Magellanic Cloud (SMC) have long confounded us. The SMC is widely used as a prototype for galactic physics at low metallicity, and yet we fundamentally lack an understanding of the stru... Read More about A Galactic Eclipse: The Small Magellanic Cloud Is Forming Stars in Two Superimposed Systems.

The EDIBLES survey: VII. A survey of C2 and C3 in interstellar clouds (2023)
Journal Article
Fan, H., Rocha, C. M. R., Cordiner, M., Linnartz, H., Cox, N. L. J., Farhang, A., Smoker, J., Roueff, E., Ehrenfreund, P., Salama, F., Foing, B. H., Lallement, R., MacIsaac, H., Kulik, K., Sarre, P., van Loon, J. T., & Cami, J. (2024). The EDIBLES survey: VII. A survey of C2 and C3 in interstellar clouds. Astronomy & Astrophysics, 681, Article A6. https://doi.org/10.1051/0004-6361/202243910

Context. Small linear carbon chain radicals such as C2 and C3 act as both the building blocks and dissociation fragments of larger carbonaceous species. Their rotational excitation traces the temperature and density of local environments. However, th... Read More about The EDIBLES survey: VII. A survey of C2 and C3 in interstellar clouds.

The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. V. The Star Formation History of Sagittarius Dwarf Irregular Galaxy Derived from Long-period Variable Stars (2023)
Journal Article
Van Loon, J. (2023). The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. V. The Star Formation History of Sagittarius Dwarf Irregular Galaxy Derived from Long-period Variable Stars. Astrophysical Journal, https://doi.org/10.3847/1538-4357/aca471

We conducted an optical monitoring survey of the Sagittarius dwarf irregular galaxy (SagDIG) during the period of 2016 June–2017 October, using the 2.5 m Isaac Newton Telescopeat La Palama. Our goal was to identify long-period variable stars (LPVs),... Read More about The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. V. The Star Formation History of Sagittarius Dwarf Irregular Galaxy Derived from Long-period Variable Stars.

The VLT-FLAMES Tarantula Survey Observational evidence for two distinct populations of massive runaway stars in 30 Doradus (2022)
Journal Article
Observational evidence for two distinct populations of massive runaway stars in 30 Doradus. Astronomy & Astrophysics, https://doi.org/10.1051/0004-6361/202244677

Context. The origin of massive runaway stars is an important unsolved problem in astrophysics. Two main scenarios have been proposed, namely: dynamical ejection or release from a binary at the first core collapse. However, their relative contribution... Read More about The VLT-FLAMES Tarantula Survey Observational evidence for two distinct populations of massive runaway stars in 30 Doradus.

GASKAP-HI Pilot Survey Science III: An unbiased view of cold gas in the Small Magellanic Cloud (2022)
Journal Article
Van Loon. (2022). GASKAP-HI Pilot Survey Science III: An unbiased view of cold gas in the Small Magellanic Cloud. Publications of the Astronomical Society of Australia, https://doi.org/10.1017/pasa.2022.18

<jats:title>Abstract</jats:title> <jats:p>We present the first unbiased survey of neutral hydrogen absorption in the Small Magellanic Cloud. The survey utilises pilot neutral hydrogen observations with the Australian Square Kilometre Array Pathfinder... Read More about GASKAP-HI Pilot Survey Science III: An unbiased view of cold gas in the Small Magellanic Cloud.

The VMC survey – XLVII. Turbulence-controlled hierarchical star formation in the Large Magellanic Cloud (2022)
Journal Article
Miller, A. E., Cioni, M.-R. L., de Grijs, R., Sun, N.-C., Bell, C. P. M., Choudhury, S., Ivanov, V. D., Marconi, M., Oliveira, J. M., Petr–Gotzens, M., Ripepi, V., & Van Loon, J. T. (2022). The VMC survey – XLVII. Turbulence-controlled hierarchical star formation in the Large Magellanic Cloud. Monthly Notices of the Royal Astronomical Society, 512(1), 1196-1213. https://doi.org/10.1093/mnras/stac508

We perform a statistical clustering analysis of upper main-sequence stars in the Large Magellanic Cloud (LMC) using data from the Visible and Infrared Survey Telescope for Astronomy survey of the Magellanic Clouds. We map over 2500 young stellar stru... Read More about The VMC survey – XLVII. Turbulence-controlled hierarchical star formation in the Large Magellanic Cloud.

Evolutionary map of the Universe (EMU): 18-cm OH-maser discovery in ASKAP continuum images of the SCORPIO field (2022)
Journal Article
Ingallinera, A., Cavallaro, F., Loru, S., Marvil, J., Umana, G., Trigilio, C., Breen, S., Bordiu, C., Buemi, C. S., Bufano, F., Collier, J., Etoka, S., Filipović, M. D., Goldman, S. R., Hopkins, A. M., Koribalski, B. S., Leto, P., Norris, R. P., Riggi, S., Schillirò, F., …Van Loon, J. T. (2022). Evolutionary map of the Universe (EMU): 18-cm OH-maser discovery in ASKAP continuum images of the SCORPIO field. Monthly Notices of the Royal Astronomical Society: Letters, 512(1), L21-L26. https://doi.org/10.1093/mnrasl/slac017

Low- and intermediate-mass stars end their life dispersing their outer layers into the circumstellar medium, during the asymptotic and post-asymptotic giant branch phases. OH masers at 18 cm offer an effective way to probe their circumstellar environ... Read More about Evolutionary map of the Universe (EMU): 18-cm OH-maser discovery in ASKAP continuum images of the SCORPIO field.

Presence of red giant population in the foreground stellar substructure of the Small Magellanic Cloud (2021)
Journal Article
Van Loon. (2021). Presence of red giant population in the foreground stellar substructure of the Small Magellanic Cloud. Monthly Notices of the Royal Astronomical Society, 5854 - 5863. https://doi.org/10.1093/mnras/stab2873

<jats:title>ABSTRACT</jats:title> <jats:p>The eastern region of the Small Magellanic Cloud (SMC) is found to have a foreground stellar substructure, which is identified as a distance bimodality (~12?kpc apart) in the previous studies using red clump... Read More about Presence of red giant population in the foreground stellar substructure of the Small Magellanic Cloud.

Radio continuum sources behind the Large Magellanic Cloud (2021)
Journal Article
Van Loon. (2021). Radio continuum sources behind the Large Magellanic Cloud. Monthly Notices of the Royal Astronomical Society, 2885 - 2904. https://doi.org/10.1093/mnras/stab2249

We present a comprehensive multifrequency catalogue of radio sources behind the Large Magellanic Cloud (LMC) between 0.2 and 20 GHz, gathered from a combination of new and legacy radio continuum surveys. This catalogue covers an area of ~144 deg2 at... Read More about Radio continuum sources behind the Large Magellanic Cloud.

The VMC survey – XLIV: Mapping metallicity trends in the large magellanic cloud using near-infrared passbands (2021)
Journal Article
Choudhury, S., de Grijs, R., Bekki, K., Cioni, M.-R. L., Ivanov, V. D., Van Loon, J. T., Miller, A. E., Niederhofer, F., Oliveira, J. M., Ripepi, V., Sun, N.-C., & Subramanian, S. (2021). The VMC survey – XLIV: Mapping metallicity trends in the large magellanic cloud using near-infrared passbands. Monthly Notices of the Royal Astronomical Society, 507(4), 4752-4763. https://doi.org/10.1093/mnras/stab2446

We have derived high-spatial-resolution metallicity maps covering ~105 deg2 across the Large Magellanic Cloud (LMC) using near-infrared passbands from the VISTA Survey of the Magellanic Clouds. We attempt to understand the metallicity distribution an... Read More about The VMC survey – XLIV: Mapping metallicity trends in the large magellanic cloud using near-infrared passbands.

Massive young stellar objects in the Local Group irregular galaxy NGC6822 identified using machine learning (2021)
Journal Article
Kinson, D. A., Oliveira, J., & Van Loon, J. (2021). Massive young stellar objects in the Local Group irregular galaxy NGC6822 identified using machine learning. Monthly Notices of the Royal Astronomical Society, 507(4), 5106 - 5131. https://doi.org/10.1093/mnras/stab2386

We present a supervised machine learning methodology to classify stellar populations in the Local Group dwarf-irregular galaxy NGC?6822. Near-IR colours (J - H, H - K, and J - K), K-band magnitudes and far-IR surface brightness (at 70 and 160?µm) mea... Read More about Massive young stellar objects in the Local Group irregular galaxy NGC6822 identified using machine learning.

The VMC Survey – XL. Three-dimensional structure of the Small Magellanic Cloud as derived from red clump stars (2021)
Journal Article
Tatton, B. L., Van Loon, J. T., Cioni, M.-R. L., Bekki, K., Bell, C. P. M., Choudhury, S., de Grijs, R., Groenewegen, M. A. T., Ivanov, V. D., Marconi, M., Oliveira, J. M., Ripepi, V., Rubele, S., Subramanian, S., & Sun, N.-C. (2021). The VMC Survey – XL. Three-dimensional structure of the Small Magellanic Cloud as derived from red clump stars. Monthly Notices of the Royal Astronomical Society, 504(2), 2983 - 2997. https://doi.org/10.1093/mnras/staa3857

Galaxy interactions distort the distribution of baryonic matter and can affect star formation. The nearby Magellanic Clouds are a prime example of an ongoing galaxy interaction process. Here, we use the intermediate-age (similar to 1-10 Gyr) red clum... Read More about The VMC Survey – XL. Three-dimensional structure of the Small Magellanic Cloud as derived from red clump stars.

Constraining the thermally pulsing asymptotic giant branch phase with resolved stellar populations in the Large Magellanic Cloud (2020)
Journal Article
Van Loon. (2020). Constraining the thermally pulsing asymptotic giant branch phase with resolved stellar populations in the Large Magellanic Cloud. Monthly Notices of the Royal Astronomical Society, 3283-3301. https://doi.org/10.1093/mnras/staa2565

Reliable models of the thermally pulsing asymptotic giant branch (TP-AGB) phase are of critical importance across astrophysics, including our interpretation of the spectral energy distribution of galaxies, cosmic dust production, and enrichment of th... Read More about Constraining the thermally pulsing asymptotic giant branch phase with resolved stellar populations in the Large Magellanic Cloud.

The VMC survey – XXXIX: Mapping metallicity trends in the Small Magellanic Cloud using near-infrared passbands (2020)
Journal Article
Choudhury, S., de Grijs, R., Rubele, S., Bekki, K., Cioni, M.-R. L., Ivanov, V. D., Van Loon, J. T., Niederhofer, F., Oliveira, J. M., & Ripepi, V. (2020). The VMC survey – XXXIX: Mapping metallicity trends in the Small Magellanic Cloud using near-infrared passbands. Monthly Notices of the Royal Astronomical Society, 497(3), 3746-3760. https://doi.org/10.1093/mnras/staa2140

We have derived high spatial resolution metallicity maps covering ~42 deg2 across the Small Magellanic Cloud (SMC) in an attempt to understand its metallicity distribution and gradients up to a radius of ~ 4?. Using the near-infrared VISTA Survey of... Read More about The VMC survey – XXXIX: Mapping metallicity trends in the Small Magellanic Cloud using near-infrared passbands.

The VMC Survey - XXXVII. Pulsation periods of dust-enshrouded AGB stars in the Magellanic Clouds (2020)
Journal Article
Groenewegen, M. A. T., Nanni, A., Cioni, M.-R. L., Girardi, L., de Grijs, R., Ivanov, V. D., Marconi, M., Moretti, M.-., Oliveira, J. M., Petr-Gotzens, M. G., Ripepi, V., & Van Loon, J. T. (2020). The VMC Survey - XXXVII. Pulsation periods of dust-enshrouded AGB stars in the Magellanic Clouds. Astronomy and Astrophysics, 636, Article A48. https://doi.org/10.1051/0004-6361/201937271

Context. Variability is a key property of stars on the asymptotic giant branch (AGB). Their pulsation period is related to the luminosity and mass-loss rate of the star. Long-period variables (LPVs) and Mira variables are the most prominent of all ty... Read More about The VMC Survey - XXXVII. Pulsation periods of dust-enshrouded AGB stars in the Magellanic Clouds.

Equality, diversity and inclusion perspectives (2019)
Journal Article
Van Loon. (2019). Equality, diversity and inclusion perspectives. Astronomy and Geophysics, 5.40 - 5.42. https://doi.org/10.1093/astrogeo/atz182

An overview of the developments arising from equality, diversity and inclusion events at this year’s National Astronomy Meeting, by Vinesh Maguire-Rajpaul on behalf of the organizers.

CK Vul: a smorgasbord of hydrocarbons rules out a 1670 nova (and much else besides) (2016)
Journal Article
Van Loon. (2016). CK Vul: a smorgasbord of hydrocarbons rules out a 1670 nova (and much else besides). Monthly Notices of the Royal Astronomical Society, 2871 - 2876. https://doi.org/10.1093/mnras/stw352

We present observations of CK Vul obtained with the Spitzer Space Telescope. The infrared spectrum reveals a warm dust continuum with nebular, molecular hydrogen and HCN lines superimposed, together with the ‘Unidentified Infrared’ features. The nebu... Read More about CK Vul: a smorgasbord of hydrocarbons rules out a 1670 nova (and much else besides).

New quasars behind the Magellanic Clouds. Spectroscopic confirmation of near-infrared selected candidates (2016)
Journal Article
Van Loon. (2016). New quasars behind the Magellanic Clouds. Spectroscopic confirmation of near-infrared selected candidates. Astronomy & Astrophysics, https://doi.org/10.1051/0004-6361/201527398

Context. Quasi-stellar objects (quasars) located behind nearby galaxies provide an excellent absolute reference system for astrometric studies, but they are difficult to identify because of fore- and background contamination. Deep wide-field, high an... Read More about New quasars behind the Magellanic Clouds. Spectroscopic confirmation of near-infrared selected candidates.

The UK Infrared Telescope M33 monitoring project - IV. Variable red giant stars across the galactic disc (2015)
Journal Article
Van Loon. (2015). The UK Infrared Telescope M33 monitoring project - IV. Variable red giant stars across the galactic disc. Monthly Notices of the Royal Astronomical Society, 3973 -3991. https://doi.org/10.1093/mnras/stu2637

We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope, of the Local Group spiral galaxy M33 (Triangulum). The main aim was to identify stars in the very final stage of their evolution, and for which the luminosity is more... Read More about The UK Infrared Telescope M33 monitoring project - IV. Variable red giant stars across the galactic disc.