Dwarf Galaxies in Voids: Dark Matter Halos and Gas Cooling
Galaxy surveys have shown that luminous galaxies are mainly distributed in large filaments and galaxy clusters. The remaining large volumes are virtually devoid of luminous galaxies. This is in concordance with the formation of the large-scale structure in the universe as derived from cosmological s...
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| Format: | Article |
| Language: | English |
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Wiley
2010-01-01
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| Series: | Advances in Astronomy |
| Online Access: | http://dx.doi.org/10.1155/2010/693968 |
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| _version_ | 1832553756659548160 |
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| author | Matthias Hoeft Stefan Gottlöber |
| author_facet | Matthias Hoeft Stefan Gottlöber |
| author_sort | Matthias Hoeft |
| collection | DOAJ |
| description | Galaxy surveys have shown that luminous galaxies are mainly distributed in large filaments and galaxy clusters. The remaining large volumes are virtually devoid of luminous galaxies. This is in concordance with the formation of the large-scale structure in the universe as derived from cosmological simulations. However, the numerical results indicate that cosmological voids are abundantly populated with dark matter haloes which may in principle host dwarf galaxies. Observational efforts have in contrast revealed that voids are apparently devoid of dwarf galaxies. We investigate the formation of dwarf galaxies in voids by hydrodynamical cosmological simulations. Due to the cosmic ultraviolet background radiation low-mass haloes show generally a reduced baryon fraction. We determine the characteristic mass below which dwarf galaxies are baryon deficient. We show that the circular velocity below which the accretion of baryons is suppressed is approximately 40 kms−1. The suppressed baryon accretion is caused by the photo-heating due to the UV background. We set up a spherical halo model and show that the effective equation of the state of the gas in the periphery of dwarf galaxies determines the characteristic mass. This implies that any process which heats the gas around dwarf galaxies increases the characteristic mass and thus reduces the number of observable dwarf galaxies. |
| format | Article |
| id | doaj-art-71eaf05f2cab4e2491ad5e4ae35f3fad |
| institution | Kabale University |
| issn | 1687-7969 1687-7977 |
| language | English |
| publishDate | 2010-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Astronomy |
| spelling | doaj-art-71eaf05f2cab4e2491ad5e4ae35f3fad2025-02-03T05:53:23ZengWileyAdvances in Astronomy1687-79691687-79772010-01-01201010.1155/2010/693968693968Dwarf Galaxies in Voids: Dark Matter Halos and Gas CoolingMatthias Hoeft0Stefan Gottlöber1Thüringer Landessternwarte Tautenburg, 07778 Tautenburg, GermanyAstrophysikalisches Institut Potsdam, 14482 Potsdam, GermanyGalaxy surveys have shown that luminous galaxies are mainly distributed in large filaments and galaxy clusters. The remaining large volumes are virtually devoid of luminous galaxies. This is in concordance with the formation of the large-scale structure in the universe as derived from cosmological simulations. However, the numerical results indicate that cosmological voids are abundantly populated with dark matter haloes which may in principle host dwarf galaxies. Observational efforts have in contrast revealed that voids are apparently devoid of dwarf galaxies. We investigate the formation of dwarf galaxies in voids by hydrodynamical cosmological simulations. Due to the cosmic ultraviolet background radiation low-mass haloes show generally a reduced baryon fraction. We determine the characteristic mass below which dwarf galaxies are baryon deficient. We show that the circular velocity below which the accretion of baryons is suppressed is approximately 40 kms−1. The suppressed baryon accretion is caused by the photo-heating due to the UV background. We set up a spherical halo model and show that the effective equation of the state of the gas in the periphery of dwarf galaxies determines the characteristic mass. This implies that any process which heats the gas around dwarf galaxies increases the characteristic mass and thus reduces the number of observable dwarf galaxies.http://dx.doi.org/10.1155/2010/693968 |
| spellingShingle | Matthias Hoeft Stefan Gottlöber Dwarf Galaxies in Voids: Dark Matter Halos and Gas Cooling Advances in Astronomy |
| title | Dwarf Galaxies in Voids: Dark Matter Halos and Gas Cooling |
| title_full | Dwarf Galaxies in Voids: Dark Matter Halos and Gas Cooling |
| title_fullStr | Dwarf Galaxies in Voids: Dark Matter Halos and Gas Cooling |
| title_full_unstemmed | Dwarf Galaxies in Voids: Dark Matter Halos and Gas Cooling |
| title_short | Dwarf Galaxies in Voids: Dark Matter Halos and Gas Cooling |
| title_sort | dwarf galaxies in voids dark matter halos and gas cooling |
| url | http://dx.doi.org/10.1155/2010/693968 |
| work_keys_str_mv | AT matthiashoeft dwarfgalaxiesinvoidsdarkmatterhalosandgascooling AT stefangottlober dwarfgalaxiesinvoidsdarkmatterhalosandgascooling |