Multi-wavelength morphology and dust emission in low-redshift dwarf galaxies in COSMOS-Web with HST and JWST

D. Kakkad; I. Lazar; S. Harish; B. Bichang'a; R. K. Cochrane; S. Kaviraj; A. E. Watkins; G. Martin; S. Koudmani; Andrew J. Battisti; Caitlin Casey; Maximilien Franco; G. Gozaliasl; M. Hirschmann; Jeyhan Kartaltepe; A. A. Khostovan; Anton Koekemoer; Daizhong Liu; Henry Joy McCracken; Jason Rhodes; Brant Robertson

doi:10.1093/mnras/stag267

Multi-wavelength morphology and dust emission in low-redshift dwarf galaxies in COSMOS-Web with HST and JWST

D. Kakkad
, I. Lazar
, S. Harish
, B. Bichang'a
, R. K. Cochrane
, S. Kaviraj
, A. E. Watkins
, G. Martin
, S. Koudmani
, Andrew J. Battisti
, Caitlin Casey
, Maximilien Franco
, G. Gozaliasl
, M. Hirschmann
, Jeyhan Kartaltepe
, A. A. Khostovan
, Anton Koekemoer
, Daizhong Liu
, Henry Joy McCracken
, Jason Rhodes

Brant Robertson

Research output: Contribution to journal › Article › peer-review

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Abstract

Low-mass or dwarf galaxies (M∗ < 109 M) are abundant in the Universe, yet their formation and evolution remain
poorly understood. Their enhanced sensitivity to feedback from star formation and active galactic nuclei (AGNs) make
them excellent laboratories to test whether feedback prescriptions in cosmological simulations accurately reproduce their
interstellar medium (ISM) properties. We present James Webb Space Telescope/near-infrared camera (JWST/NIRCam)
and mid-infrared instrument (MIRI) imaging of nine dwarf galaxies from COSMOS-Web survey at redshift z < 0.08,
with star formation rates ranging from 0.003 to 0.3 M yr−1 and stellar masses of log M∗ ∼ 8–9 M. The detection
rate with both NIRCam and MIRI is 100 per cent, indicating that these dwarfs possess substantial ISM content. The
detected sample includes a roughly equal mix of early-type and late-type dwarfs, suggesting that it is representative of
the broader dwarf galaxy population in low-density environments. We find that the observed MIRI flux distributions are
comparable to forward-modelled flux distributions of mass-matched simulated galaxies in TNG50. We further conduct
a multiwavelength morphological analysis complementing the JWST NIRCam and MIRI imaging with archival Hubble
Space Telescope/Advanced Camera for Surveys (HST/ACS) data, employing the CAS (concentration, asymmetry, smoothness) framework. Among the multiwavelength images, MIRI exhibitsthe largest variation in CAS parameters, likely due to
dust lanes and clumpsin several galaxies, also suggested by spectral energy distribution (SED) fitting. Thissuggeststhat the
dust content in these systems may be higher than those implied by rest-frame optical or near-infrared observations alone.
Upcoming ultraviolet/optical and mid-infrared spectroscopic follow-up will be critical for constraining the gas kinematics
and dust grain properties of dwarf galaxies in low-density environments such as COSMOS.

Original language	English
Article number	stag267
Number of pages	17
Journal	Monthly Notices of the Royal Astronomical Society (MNRAS)
Volume	547
Issue number	4
Early online date	11 Feb 2026
DOIs	https://doi.org/10.1093/mnras/stag267
Publication status	Published - 30 Apr 2026

Keywords

astro-ph.GA

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10.1093/mnras/stag267Licence: CC BY

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© The Author(s) 2026. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/
Final published version, 8.81 MBLicence: CC BY

Cite this

Kakkad, D., Lazar, I., Harish, S., Bichang'a, B., Cochrane, R. K., Kaviraj, S., Watkins, A. E., Martin, G., Koudmani, S., Battisti, A. J., Casey, C., Franco, M., Gozaliasl, G., Hirschmann, M., Kartaltepe, J., Khostovan, A. A., Koekemoer, A., Liu, D., McCracken, H. J., ... Robertson, B. (2026). Multi-wavelength morphology and dust emission in low-redshift dwarf galaxies in COSMOS-Web with HST and JWST. Monthly Notices of the Royal Astronomical Society (MNRAS), 547(4), Article stag267. https://doi.org/10.1093/mnras/stag267

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title = "Multi-wavelength morphology and dust emission in low-redshift dwarf galaxies in COSMOS-Web with HST and JWST",

abstract = "Low-mass or dwarf galaxies (M∗ < 109 M) are abundant in the Universe, yet their formation and evolution remain poorly understood. Their enhanced sensitivity to feedback from star formation and active galactic nuclei (AGNs) make them excellent laboratories to test whether feedback prescriptions in cosmological simulations accurately reproduce their interstellar medium (ISM) properties. We present James Webb Space Telescope/near-infrared camera (JWST/NIRCam) and mid-infrared instrument (MIRI) imaging of nine dwarf galaxies from COSMOS-Web survey at redshift z < 0.08, with star formation rates ranging from 0.003 to 0.3 M yr−1 and stellar masses of log M∗ ∼ 8–9 M. The detection rate with both NIRCam and MIRI is 100 per cent, indicating that these dwarfs possess substantial ISM content. The detected sample includes a roughly equal mix of early-type and late-type dwarfs, suggesting that it is representative of the broader dwarf galaxy population in low-density environments. We find that the observed MIRI flux distributions are comparable to forward-modelled flux distributions of mass-matched simulated galaxies in TNG50. We further conduct a multiwavelength morphological analysis complementing the JWST NIRCam and MIRI imaging with archival Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) data, employing the CAS (concentration, asymmetry, smoothness) framework. Among the multiwavelength images, MIRI exhibitsthe largest variation in CAS parameters, likely due to dust lanes and clumpsin several galaxies, also suggested by spectral energy distribution (SED) fitting. Thissuggeststhat the dust content in these systems may be higher than those implied by rest-frame optical or near-infrared observations alone. Upcoming ultraviolet/optical and mid-infrared spectroscopic follow-up will be critical for constraining the gas kinematics and dust grain properties of dwarf galaxies in low-density environments such as COSMOS.",

keywords = "astro-ph.GA",

author = "D. Kakkad and I. Lazar and S. Harish and B. Bichang'a and Cochrane, \{R. K.\} and S. Kaviraj and Watkins, \{A. E.\} and G. Martin and S. Koudmani and Battisti, \{Andrew J.\} and Caitlin Casey and Maximilien Franco and G. Gozaliasl and M. Hirschmann and Jeyhan Kartaltepe and Khostovan, \{A. A.\} and Anton Koekemoer and Daizhong Liu and McCracken, \{Henry Joy\} and Jason Rhodes and Brant Robertson",

note = "{\textcopyright} The Author(s) 2026. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/",

year = "2026",

month = apr,

day = "30",

doi = "10.1093/mnras/stag267",

language = "English",

volume = "547",

journal = "Monthly Notices of the Royal Astronomical Society (MNRAS)",

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publisher = "Oxford University Press (OUP)",

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Kakkad, D, Lazar, I, Harish, S, Bichang'a, B, Cochrane, RK, Kaviraj, S, Watkins, AE, Martin, G, Koudmani, S, Battisti, AJ, Casey, C, Franco, M, Gozaliasl, G, Hirschmann, M, Kartaltepe, J, Khostovan, AA, Koekemoer, A, Liu, D, McCracken, HJ, Rhodes, J & Robertson, B 2026, 'Multi-wavelength morphology and dust emission in low-redshift dwarf galaxies in COSMOS-Web with HST and JWST', Monthly Notices of the Royal Astronomical Society (MNRAS), vol. 547, no. 4, stag267. https://doi.org/10.1093/mnras/stag267

TY - JOUR

T1 - Multi-wavelength morphology and dust emission in low-redshift dwarf galaxies in COSMOS-Web with HST and JWST

AU - Kakkad, D.

AU - Lazar, I.

AU - Harish, S.

AU - Bichang'a, B.

AU - Cochrane, R. K.

AU - Kaviraj, S.

AU - Watkins, A. E.

AU - Martin, G.

AU - Koudmani, S.

AU - Battisti, Andrew J.

AU - Casey, Caitlin

AU - Franco, Maximilien

AU - Gozaliasl, G.

AU - Hirschmann, M.

AU - Kartaltepe, Jeyhan

AU - Khostovan, A. A.

AU - Koekemoer, Anton

AU - Liu, Daizhong

AU - McCracken, Henry Joy

AU - Rhodes, Jason

AU - Robertson, Brant

N1 - © The Author(s) 2026. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/

PY - 2026/4/30

Y1 - 2026/4/30

N2 - Low-mass or dwarf galaxies (M∗ < 109 M) are abundant in the Universe, yet their formation and evolution remain poorly understood. Their enhanced sensitivity to feedback from star formation and active galactic nuclei (AGNs) make them excellent laboratories to test whether feedback prescriptions in cosmological simulations accurately reproduce their interstellar medium (ISM) properties. We present James Webb Space Telescope/near-infrared camera (JWST/NIRCam) and mid-infrared instrument (MIRI) imaging of nine dwarf galaxies from COSMOS-Web survey at redshift z < 0.08, with star formation rates ranging from 0.003 to 0.3 M yr−1 and stellar masses of log M∗ ∼ 8–9 M. The detection rate with both NIRCam and MIRI is 100 per cent, indicating that these dwarfs possess substantial ISM content. The detected sample includes a roughly equal mix of early-type and late-type dwarfs, suggesting that it is representative of the broader dwarf galaxy population in low-density environments. We find that the observed MIRI flux distributions are comparable to forward-modelled flux distributions of mass-matched simulated galaxies in TNG50. We further conduct a multiwavelength morphological analysis complementing the JWST NIRCam and MIRI imaging with archival Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) data, employing the CAS (concentration, asymmetry, smoothness) framework. Among the multiwavelength images, MIRI exhibitsthe largest variation in CAS parameters, likely due to dust lanes and clumpsin several galaxies, also suggested by spectral energy distribution (SED) fitting. Thissuggeststhat the dust content in these systems may be higher than those implied by rest-frame optical or near-infrared observations alone. Upcoming ultraviolet/optical and mid-infrared spectroscopic follow-up will be critical for constraining the gas kinematics and dust grain properties of dwarf galaxies in low-density environments such as COSMOS.

AB - Low-mass or dwarf galaxies (M∗ < 109 M) are abundant in the Universe, yet their formation and evolution remain poorly understood. Their enhanced sensitivity to feedback from star formation and active galactic nuclei (AGNs) make them excellent laboratories to test whether feedback prescriptions in cosmological simulations accurately reproduce their interstellar medium (ISM) properties. We present James Webb Space Telescope/near-infrared camera (JWST/NIRCam) and mid-infrared instrument (MIRI) imaging of nine dwarf galaxies from COSMOS-Web survey at redshift z < 0.08, with star formation rates ranging from 0.003 to 0.3 M yr−1 and stellar masses of log M∗ ∼ 8–9 M. The detection rate with both NIRCam and MIRI is 100 per cent, indicating that these dwarfs possess substantial ISM content. The detected sample includes a roughly equal mix of early-type and late-type dwarfs, suggesting that it is representative of the broader dwarf galaxy population in low-density environments. We find that the observed MIRI flux distributions are comparable to forward-modelled flux distributions of mass-matched simulated galaxies in TNG50. We further conduct a multiwavelength morphological analysis complementing the JWST NIRCam and MIRI imaging with archival Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) data, employing the CAS (concentration, asymmetry, smoothness) framework. Among the multiwavelength images, MIRI exhibitsthe largest variation in CAS parameters, likely due to dust lanes and clumpsin several galaxies, also suggested by spectral energy distribution (SED) fitting. Thissuggeststhat the dust content in these systems may be higher than those implied by rest-frame optical or near-infrared observations alone. Upcoming ultraviolet/optical and mid-infrared spectroscopic follow-up will be critical for constraining the gas kinematics and dust grain properties of dwarf galaxies in low-density environments such as COSMOS.

KW - astro-ph.GA

U2 - 10.1093/mnras/stag267

DO - 10.1093/mnras/stag267

M3 - Article

SN - 0035-8711

VL - 547

JO - Monthly Notices of the Royal Astronomical Society (MNRAS)

JF - Monthly Notices of the Royal Astronomical Society (MNRAS)

IS - 4

M1 - stag267

ER -

Multi-wavelength morphology and dust emission in low-redshift dwarf galaxies in COSMOS-Web with HST and JWST

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