Radio properties of green pea galaxies

BORKAR, A., Romana GROSSOVÁ, J. SVOBODA, E. MORAVEC, K. KOUROUMPATZAKIS, P. G. BOORMAN, B. ADAMCOVA, B. MINGO and M. EHLE. Radio properties of green pea galaxies. Astronomy and Astrophysics. EDP Sciences, 2024, vol. 687, July 2024, p. 1-9. ISSN 0004-6361. Available from: https://dx.doi.org/10.1051/0004-6361/202348819.

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TY  - JOUR
ID  - 2421879
AU  - Borkar, A. - Grossová, Romana - Svoboda, J. - Moravec, E. - Kouroumpatzakis, K. - Boorman, P. G. - Adamcova, B. - Mingo, B. - Ehle, M.
PY  - 2024
TI  - Radio properties of green pea galaxies
JF  - Astronomy and Astrophysics
VL  - 687
IS  - July 2024
SP  - 1-9
EP  - 1-9
PB  - EDP Sciences
SN  - 00046361
KW  - galaxies: dwarf
KW  - galaxies: starburst
KW  - galaxies: star formation
KW  - radio continuum: galaxies
UR  - https://ui.adsabs.harvard.edu/abs/2024A%26A...687A.137B/abstract
N2  - Aims. Green peas (GPs) are young, compact, star-forming dwarf galaxies, and local (z ∼ 0.3) analogues of the early galaxies (z ≥ 6) considered to be mainly responsible for the reionisation of the Universe. Recent X-ray observations of GPs led to the detection of high excess emission, which cannot be accounted for by star formation alone and implies the presence of an active galactic nucleus (AGN). We employ radio observations to study the radio properties of GPs, build their radio spectral energy distributions, and verify the presence of AGNs. Methods. We performed new radio observations of three GPs with the Karl G. Jansky Very Large Array (JVLA) in the L, C, and X bands (1.4, 6 and 10 GHz resp.), and analysed them alongside data from archival observations and large radio surveys. We also analysed the archival radio data for a larger sample of GPs and blueberry (BBs) galaxies, which are lower-mass and lower-redshift analogues of the GPs. To understand the significance of the radio observations, we assess the detectability of these sources, and compare the detected radio luminosities with expectations from theoretical and empirical relations. Results. Two of the three targeted GPs are strongly detected (> 10σ) in the JVLA observations and their fluxes are consistent with star formation, while the third source is undetected. Although archival radio surveys have the sensitivity to detect a large fraction (∼75%) of the sources from the larger archival sample of GPs and BBs, we only detect a small number (< 40%) of them and their radio luminosity is significantly lower than the expectation from empirical relations. Conclusions. Our results show that the majority of the dwarf galaxies in our sample are highly underluminous. The radio luminosity–star formation rate (SFR) relation deviates from the empirical relations, especially towards the lower end of galaxy mass and SFR, suggesting that the relations established for larger galaxies may not hold towards the low-mass end.
ER  -

Basic information
Original name	Radio properties of green pea galaxies
Authors	BORKAR, A., Romana GROSSOVÁ (703 Slovakia, belonging to the institution), J. SVOBODA, E. MORAVEC, K. KOUROUMPATZAKIS, P. G. BOORMAN, B. ADAMCOVA, B. MINGO and M. EHLE.
Edition	Astronomy and Astrophysics, EDP Sciences, 2024, 0004-6361.

Other information
Original language	English
Type of outcome	Article in a journal
Field of Study	10308 Astronomy
Country of publisher	France
Confidentiality degree	is not subject to a state or trade secret
WWW	URL URL
Impact factor	Impact factor: 6.500 in 2022
Organization unit	Faculty of Science
Doi	http://dx.doi.org/10.1051/0004-6361/202348819
UT WoS	001263273200008
Keywords in English	galaxies: dwarf; galaxies: starburst; galaxies: star formation; radio continuum: galaxies
Tags	rivok
Tags	International impact, Reviewed
Changed by	Changed by: Mgr. Marie Šípková, DiS., učo 437722. Changed: 7/8/2024 10:19.

Abstract

Aims. Green peas (GPs) are young, compact, star-forming dwarf galaxies, and local (z ∼ 0.3) analogues of the early galaxies (z ≥ 6) considered to be mainly responsible for the reionisation of the Universe. Recent X-ray observations of GPs led to the detection of high excess emission, which cannot be accounted for by star formation alone and implies the presence of an active galactic nucleus (AGN). We employ radio observations to study the radio properties of GPs, build their radio spectral energy distributions, and verify the presence of AGNs. Methods. We performed new radio observations of three GPs with the Karl G. Jansky Very Large Array (JVLA) in the L, C, and X bands (1.4, 6 and 10 GHz resp.), and analysed them alongside data from archival observations and large radio surveys. We also analysed the archival radio data for a larger sample of GPs and blueberry (BBs) galaxies, which are lower-mass and lower-redshift analogues of the GPs. To understand the significance of the radio observations, we assess the detectability of these sources, and compare the detected radio luminosities with expectations from theoretical and empirical relations. Results. Two of the three targeted GPs are strongly detected (> 10σ) in the JVLA observations and their fluxes are consistent with star formation, while the third source is undetected. Although archival radio surveys have the sensitivity to detect a large fraction (∼75%) of the sources from the larger archival sample of GPs and BBs, we only detect a small number (< 40%) of them and their radio luminosity is significantly lower than the expectation from empirical relations. Conclusions. Our results show that the majority of the dwarf galaxies in our sample are highly underluminous. The radio luminosity–star formation rate (SFR) relation deviates from the empirical relations, especially towards the lower end of galaxy mass and SFR, suggesting that the relations established for larger galaxies may not hold towards the low-mass end.

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Radio properties of green pea galaxies

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