Exploring reionization and high-z galaxy observables with recent multiredshift MWA upper limits on the 21-cm signal
We use the latest multiredshift (z = 6.5-8.7) upper limits on the 21-cm signal from the Murchison Widefield Array (MWA) to explore astrophysical models which are inconsistent with the data. We explore these limits in the context of reionization astrophysics by using 21CMMC to connect the disfavoured...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
| Language: | English |
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OXFORD UNIV PRESS
2021
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| Online Access: | http://purl.org/au-research/grants/arc/FT180100321 http://hdl.handle.net/20.500.11937/91570 |
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| author | Greig, B. Trott, Cathryn Barry, Nichole Mutch, S.J. Pindor, B. Webster, R.L. Wyithe, J.S.B. |
| author_facet | Greig, B. Trott, Cathryn Barry, Nichole Mutch, S.J. Pindor, B. Webster, R.L. Wyithe, J.S.B. |
| author_sort | Greig, B. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We use the latest multiredshift (z = 6.5-8.7) upper limits on the 21-cm signal from the Murchison Widefield Array (MWA) to explore astrophysical models which are inconsistent with the data. We explore these limits in the context of reionization astrophysics by using 21CMMC to connect the disfavoured regions of parameter space to existing observational constraints on reionization such as high-z galaxy ultraviolet (UV) luminosity functions, the background UV photoionization rate, the intergalactic medium (IGM) neutral fraction, the electron scattering optical depth and the soft-band X-ray emissivity. We find the vast majority of disfavoured models to already be inconsistent with existing observational constraints. These can be broadly classified into two types of models: (i) 'cold' reionization and (ii) pure matter density fluctuations in a cold, neutral IGM (i.e. no reionization). Interestingly, a small subsample of models inconsistent with the MWA is consistent with the aforementioned constraints (excluding the X-ray emissivity). This implies that the current MWA limits are already providing unique information to disfavour models of reionization, albeit extremely weakly. We also provide the first limits on the soft-band X-ray emissivity from galaxies at high redshifts, finding 1σ lower limits of X, 0.5-2 keV 1034.5 erg s-1 Mpc-3. Finally, we recover 95 per cent disfavoured limits on the IGM spin temperature of TS 1.3, 1.4, 1.5, 1.8, 2.1, and 2.4 K at z = 6.5, 6.8, 7.1, 7.8, 8.2, and 8.7. With this, we infer the IGM must have undergone, at the very least, a small amount of X-ray heating. Note, the limits on X, 0.5-2 keV and TS are conditional on the IGM neutral fraction. |
| first_indexed | 2025-11-14T11:37:02Z |
| format | Journal Article |
| id | curtin-20.500.11937-91570 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:37:02Z |
| publishDate | 2021 |
| publisher | OXFORD UNIV PRESS |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-915702023-05-11T03:47:27Z Exploring reionization and high-z galaxy observables with recent multiredshift MWA upper limits on the 21-cm signal Greig, B. Trott, Cathryn Barry, Nichole Mutch, S.J. Pindor, B. Webster, R.L. Wyithe, J.S.B. Science & Technology Physical Sciences Astronomy & Astrophysics galaxies: high-redshift intergalactic medium dark ages, reionization, first stars diffuse radiation early Universe cosmology: theory DARK-AGES REIONIZATION APPROXIMATE-TO 9.1 H II BUBBLES POWER SPECTRUM COSMIC DAWN RADIATIVE-TRANSFER FORMATION SIMULATION LUMINOSITY FUNCTION NEUTRAL HYDROGEN EPOCH astro-ph.CO astro-ph.CO We use the latest multiredshift (z = 6.5-8.7) upper limits on the 21-cm signal from the Murchison Widefield Array (MWA) to explore astrophysical models which are inconsistent with the data. We explore these limits in the context of reionization astrophysics by using 21CMMC to connect the disfavoured regions of parameter space to existing observational constraints on reionization such as high-z galaxy ultraviolet (UV) luminosity functions, the background UV photoionization rate, the intergalactic medium (IGM) neutral fraction, the electron scattering optical depth and the soft-band X-ray emissivity. We find the vast majority of disfavoured models to already be inconsistent with existing observational constraints. These can be broadly classified into two types of models: (i) 'cold' reionization and (ii) pure matter density fluctuations in a cold, neutral IGM (i.e. no reionization). Interestingly, a small subsample of models inconsistent with the MWA is consistent with the aforementioned constraints (excluding the X-ray emissivity). This implies that the current MWA limits are already providing unique information to disfavour models of reionization, albeit extremely weakly. We also provide the first limits on the soft-band X-ray emissivity from galaxies at high redshifts, finding 1σ lower limits of X, 0.5-2 keV 1034.5 erg s-1 Mpc-3. Finally, we recover 95 per cent disfavoured limits on the IGM spin temperature of TS 1.3, 1.4, 1.5, 1.8, 2.1, and 2.4 K at z = 6.5, 6.8, 7.1, 7.8, 8.2, and 8.7. With this, we infer the IGM must have undergone, at the very least, a small amount of X-ray heating. Note, the limits on X, 0.5-2 keV and TS are conditional on the IGM neutral fraction. 2021 Journal Article http://hdl.handle.net/20.500.11937/91570 10.1093/mnras/staa3494 English http://purl.org/au-research/grants/arc/FT180100321 http://purl.org/au-research/grants/arc/CE170100013 OXFORD UNIV PRESS fulltext |
| spellingShingle | Science & Technology Physical Sciences Astronomy & Astrophysics galaxies: high-redshift intergalactic medium dark ages, reionization, first stars diffuse radiation early Universe cosmology: theory DARK-AGES REIONIZATION APPROXIMATE-TO 9.1 H II BUBBLES POWER SPECTRUM COSMIC DAWN RADIATIVE-TRANSFER FORMATION SIMULATION LUMINOSITY FUNCTION NEUTRAL HYDROGEN EPOCH astro-ph.CO astro-ph.CO Greig, B. Trott, Cathryn Barry, Nichole Mutch, S.J. Pindor, B. Webster, R.L. Wyithe, J.S.B. Exploring reionization and high-z galaxy observables with recent multiredshift MWA upper limits on the 21-cm signal |
| title | Exploring reionization and high-z galaxy observables with recent multiredshift MWA upper limits on the 21-cm signal |
| title_full | Exploring reionization and high-z galaxy observables with recent multiredshift MWA upper limits on the 21-cm signal |
| title_fullStr | Exploring reionization and high-z galaxy observables with recent multiredshift MWA upper limits on the 21-cm signal |
| title_full_unstemmed | Exploring reionization and high-z galaxy observables with recent multiredshift MWA upper limits on the 21-cm signal |
| title_short | Exploring reionization and high-z galaxy observables with recent multiredshift MWA upper limits on the 21-cm signal |
| title_sort | exploring reionization and high-z galaxy observables with recent multiredshift mwa upper limits on the 21-cm signal |
| topic | Science & Technology Physical Sciences Astronomy & Astrophysics galaxies: high-redshift intergalactic medium dark ages, reionization, first stars diffuse radiation early Universe cosmology: theory DARK-AGES REIONIZATION APPROXIMATE-TO 9.1 H II BUBBLES POWER SPECTRUM COSMIC DAWN RADIATIVE-TRANSFER FORMATION SIMULATION LUMINOSITY FUNCTION NEUTRAL HYDROGEN EPOCH astro-ph.CO astro-ph.CO |
| url | http://purl.org/au-research/grants/arc/FT180100321 http://purl.org/au-research/grants/arc/FT180100321 http://hdl.handle.net/20.500.11937/91570 |