Stellar Initial Mass Function (IMF) Probed with Supernova Rates and Neutrino Background: Cosmic-average IMF Slope Is ≃2–3 Similar to the Salpeter IMF
The stellar initial mass function (IMF) is expressed by ϕ ( m ) ∝ m ^− ^α with the slope α , and known as a poorly constrained but very important function in studies of star and galaxy formation. There are no sensible observational constraints on the IMF slopes beyond the Milky Way and nearby galaxi...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acba87 |
| _version_ | 1827827826286395392 |
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| author | Shohei Aoyama Masami Ouchi Yuichi Harikane |
| author_facet | Shohei Aoyama Masami Ouchi Yuichi Harikane |
| author_sort | Shohei Aoyama |
| collection | DOAJ |
| description | The stellar initial mass function (IMF) is expressed by ϕ ( m ) ∝ m ^− ^α with the slope α , and known as a poorly constrained but very important function in studies of star and galaxy formation. There are no sensible observational constraints on the IMF slopes beyond the Milky Way and nearby galaxies. Here we combine two sets of observational results, (1) cosmic densities of core-collapse supernova (CCSN) explosion rates and (2) cosmic far-UV radiation (and infrared reradiation) densities, which are sensitive to massive (≃8–50 M _⊙ ) and moderately massive (≃2.5–7 M _⊙ ) stars, respectively, and constrain the IMF slope at m > 1 M _⊙ with a freedom of redshift evolution. Although no redshift evolution is identified beyond the uncertainties, we find that the cosmic-average IMF slope at z = 0 is α = 1.8–3.2 at the 95% confidence level that is comparable with the Salpeter IMF, α = 2.35, which marks the first constraint on the cosmic-average IMF. We show a forecast for the Nancy Grace Roman Space Telescope supernova survey that will provide significantly strong constraints on the IMF slope with δ α ≃ 0.5 over z = 0–2. Moreover, as for an independent IMF probe instead of (1), we suggest to use diffuse supernovae neutrino background (DSNB), relic neutrinos from CCSNe. We expect that the Hyper-Kamiokande neutrino observations over 20 yr will improve the constraints on the IMF slope and the redshift evolution significantly better than those obtained today, if the systematic uncertainties of DSNB production physics are reduced in the future numerical simulations. |
| first_indexed | 2024-03-12T03:37:00Z |
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| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:37:00Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj.art-b5c13cff496841fa8f8aaf4d85488a3b2023-09-03T13:08:46ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194626910.3847/1538-4357/acba87Stellar Initial Mass Function (IMF) Probed with Supernova Rates and Neutrino Background: Cosmic-average IMF Slope Is ≃2–3 Similar to the Salpeter IMFShohei Aoyama0https://orcid.org/0000-0002-1005-4120Masami Ouchi1https://orcid.org/0000-0002-1049-6658Yuichi Harikane2https://orcid.org/0000-0002-6047-430XInstitute for Cosmic Ray Research, The University of Tokyo , Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8582, Japan ; aoyama@icrr.u-tokyo.ac.jpInstitute for Cosmic Ray Research, The University of Tokyo , Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8582, Japan ; aoyama@icrr.u-tokyo.ac.jp; National Astronomical Observatory of Japan , Osawa 2-21-1, Mitaka, Tokyo 181-8588, Japan; Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), The University of Tokyo , Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8583, JapanInstitute for Cosmic Ray Research, The University of Tokyo , Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8582, Japan ; aoyama@icrr.u-tokyo.ac.jp; Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, UKThe stellar initial mass function (IMF) is expressed by ϕ ( m ) ∝ m ^− ^α with the slope α , and known as a poorly constrained but very important function in studies of star and galaxy formation. There are no sensible observational constraints on the IMF slopes beyond the Milky Way and nearby galaxies. Here we combine two sets of observational results, (1) cosmic densities of core-collapse supernova (CCSN) explosion rates and (2) cosmic far-UV radiation (and infrared reradiation) densities, which are sensitive to massive (≃8–50 M _⊙ ) and moderately massive (≃2.5–7 M _⊙ ) stars, respectively, and constrain the IMF slope at m > 1 M _⊙ with a freedom of redshift evolution. Although no redshift evolution is identified beyond the uncertainties, we find that the cosmic-average IMF slope at z = 0 is α = 1.8–3.2 at the 95% confidence level that is comparable with the Salpeter IMF, α = 2.35, which marks the first constraint on the cosmic-average IMF. We show a forecast for the Nancy Grace Roman Space Telescope supernova survey that will provide significantly strong constraints on the IMF slope with δ α ≃ 0.5 over z = 0–2. Moreover, as for an independent IMF probe instead of (1), we suggest to use diffuse supernovae neutrino background (DSNB), relic neutrinos from CCSNe. We expect that the Hyper-Kamiokande neutrino observations over 20 yr will improve the constraints on the IMF slope and the redshift evolution significantly better than those obtained today, if the systematic uncertainties of DSNB production physics are reduced in the future numerical simulations.https://doi.org/10.3847/1538-4357/acba87Supernova neutrinosCore-collapse supernovaeOptical observationStar formationInitial mass function |
| spellingShingle | Shohei Aoyama Masami Ouchi Yuichi Harikane Stellar Initial Mass Function (IMF) Probed with Supernova Rates and Neutrino Background: Cosmic-average IMF Slope Is ≃2–3 Similar to the Salpeter IMF The Astrophysical Journal Supernova neutrinos Core-collapse supernovae Optical observation Star formation Initial mass function |
| title | Stellar Initial Mass Function (IMF) Probed with Supernova Rates and Neutrino Background: Cosmic-average IMF Slope Is ≃2–3 Similar to the Salpeter IMF |
| title_full | Stellar Initial Mass Function (IMF) Probed with Supernova Rates and Neutrino Background: Cosmic-average IMF Slope Is ≃2–3 Similar to the Salpeter IMF |
| title_fullStr | Stellar Initial Mass Function (IMF) Probed with Supernova Rates and Neutrino Background: Cosmic-average IMF Slope Is ≃2–3 Similar to the Salpeter IMF |
| title_full_unstemmed | Stellar Initial Mass Function (IMF) Probed with Supernova Rates and Neutrino Background: Cosmic-average IMF Slope Is ≃2–3 Similar to the Salpeter IMF |
| title_short | Stellar Initial Mass Function (IMF) Probed with Supernova Rates and Neutrino Background: Cosmic-average IMF Slope Is ≃2–3 Similar to the Salpeter IMF |
| title_sort | stellar initial mass function imf probed with supernova rates and neutrino background cosmic average imf slope is ≃2 3 similar to the salpeter imf |
| topic | Supernova neutrinos Core-collapse supernovae Optical observation Star formation Initial mass function |
| url | https://doi.org/10.3847/1538-4357/acba87 |
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