The Astrophysical Journal (Jan 2024)
A Galactic Eclipse: The Small Magellanic Cloud Is Forming Stars in Two Superimposed Systems
- Claire E. Murray,
- Sten Hasselquist,
- Joshua E. G. Peek,
- Christina Willecke Lindberg,
- Andres Almeida,
- Yumi Choi,
- Jessica E. M. Craig,
- Helga Dénes,
- John M. Dickey,
- Enrico M. Di Teodoro,
- Christoph Federrath,
- Isabella. A. Gerrard,
- Steven J. Gibson,
- Denis Leahy,
- Min-Young Lee,
- Callum Lynn,
- Yik Ki Ma,
- Antoine Marchal,
- N. M. McClure-Griffiths,
- David Nidever,
- Hiep Nguyen,
- Nickolas M. Pingel,
- Elizabeth Tarantino,
- Lucero Uscanga,
- Jacco Th. van Loon
Affiliations
- Claire E. Murray
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA ; [email protected]; Department of Physics & Astronomy, Johns Hopkins University , 3400 North Charles Street, Baltimore, MD 21218, USA
- Sten Hasselquist
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA ; [email protected]
- Joshua E. G. Peek
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA ; [email protected]; Department of Physics & Astronomy, Johns Hopkins University , 3400 North Charles Street, Baltimore, MD 21218, USA
- Christina Willecke Lindberg
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA ; [email protected]; Department of Physics & Astronomy, Johns Hopkins University , 3400 North Charles Street, Baltimore, MD 21218, USA
- Andres Almeida
- ORCiD
- Department of Astronomy, University of Virginia , Charlottesville, VA 22904, USA
- Yumi Choi
- ORCiD
- NOIRLab , 950 North Cherry Avenue, Tucson, AZ 85719, USA
- Jessica E. M. Craig
- ORCiD
- Lennard-Jones Laboratories, Keele University , ST5 5BG, UK
- Helga Dénes
- ORCiD
- School of Physical Sciences and Nanotechnology, Yachay Tech University , Hacienda San José S/N, 100119, Urcuquí, Ecuador
- John M. Dickey
- ORCiD
- School of Natural Sciences, Private Bag 37, University of Tasmania , Hobart, TAS, Australia
- Enrico M. Di Teodoro
- ORCiD
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze , 50019 Sesto Fiorentino, Italy
- Christoph Federrath
- ORCiD
- Research School of Astronomy and Astrophysics, Australian National University , Canberra, ACT 2611, Australia; Australian Research Council Centre of Excellence in All Sky Astrophysics (ASTRO3D) , Canberra, ACT 2611, Australia
- Isabella. A. Gerrard
- ORCiD
- Research School of Astronomy and Astrophysics, Australian National University , Canberra, ACT 2611, Australia
- Steven J. Gibson
- ORCiD
- Department of Physics & Astronomy, Western Kentucky University , 1906 College Heights Boulevard, Bowling Green, KY 42101, USA
- Denis Leahy
- ORCiD
- Department of Physics & Astronomy, University of Calgary , 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
- Min-Young Lee
- ORCiD
- Korea Astronomy and Space Science Institute , 776 Daedeok-daero, Daejeon 34055, Republic of Korea; Department of Astronomy and Space Science, University of Science and Technology , 217 Gajeong-ro, Daejeon 34113, Republic of Korea
- Callum Lynn
- ORCiD
- Research School of Astronomy and Astrophysics, Australian National University , Canberra, ACT 2611, Australia
- Yik Ki Ma
- ORCiD
- Research School of Astronomy and Astrophysics, Australian National University , Canberra, ACT 2611, Australia
- Antoine Marchal
- ORCiD
- Research School of Astronomy and Astrophysics, Australian National University , Canberra, ACT 2611, Australia
- N. M. McClure-Griffiths
- ORCiD
- Research School of Astronomy and Astrophysics, Australian National University , Canberra, ACT 2611, Australia
- David Nidever
- ORCiD
- Department of Physics, Montana State University , P.O. Box 173840, Bozeman, MT 59717-3840, USA
- Hiep Nguyen
- ORCiD
- Research School of Astronomy and Astrophysics, Australian National University , Canberra, ACT 2611, Australia
- Nickolas M. Pingel
- ORCiD
- Department of Astronomy, The University of Wisconsin–Madison , 475 North Charter Street, Madison, WI 53706, USA
- Elizabeth Tarantino
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA ; [email protected]
- Lucero Uscanga
- ORCiD
- Departamento de Astronomía, Universidad de Guanajuato , A.P. 144, 36000 Guanajuato, Gto., Mexico
- Jacco Th. van Loon
- ORCiD
- Lennard-Jones Laboratories, Keele University , ST5 5BG, UK
- DOI
- https://doi.org/10.3847/1538-4357/ad1591
- Journal volume & issue
-
Vol. 962,
no. 2
p. 120
Abstract
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 structure of its interstellar medium (ISM). In this work, we present a new model for the SMC by comparing the kinematics of young, massive stars with the structure of the ISM traced by high-resolution observations of neutral atomic hydrogen (H i ) from the Galactic Australian Square Kilometre Array Pathfinder survey. Specifically, we identify thousands of young, massive stars with precise radial velocity constraints from the Gaia and APOGEE surveys and match these stars to the ISM structures in which they likely formed. By comparing the average dust extinction toward these stars, we find evidence that the SMC is composed of two structures with distinct stellar and gaseous chemical compositions. We construct a simple model that successfully reproduces the observations and shows that the ISM of the SMC is arranged into two superimposed, star-forming systems with similar gas mass separated by ∼5 kpc along the line of sight.
Keywords
- Interstellar medium
- Small Magellanic Cloud
- Dwarf galaxies
- Galaxy structure
- Radio astronomy
- Chemical abundances
