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Papers by Piero Madau

Research paper thumbnail of At the heart of the matter: the origin of bulgeless dwarf galaxies and Dark Matter cores

For almost two decades the properties of "dwarf" galaxies have challenged the Cold Dark... more For almost two decades the properties of "dwarf" galaxies have challenged the Cold Dark Matter (CDM) paradigm of galaxy formation. Most observed dwarf galaxies consists of a rotating stellar disc embedded in a massive DM halo with a near constant-density core. Yet, models based on the CDM scenario invariably form galaxies with dense spheroidal stellar "bulges" and steep central DM

Research paper thumbnail of A galaxy as the source of a C iv absorption system close to the epoch of reionization★

Monthly Notices of the Royal Astronomical Society, 2011

A galaxy as the source of a C iv absorption system close to the epoch of reionization ⋆ ABSTRACT ... more A galaxy as the source of a C iv absorption system close to the epoch of reionization ⋆ ABSTRACT We find a bright (L UV = 2.5 L ⋆ z=6 ) Lyman alpha emitter (LAE) at redshift z = 5.719 at a projected distance of 79 physical kpc from a strong triply ionized carbon (C iv) absorption system at redshift z = 5.7238 previously reported in the spectrum of the z em = 6.309 QSO SDSS J1030+0524. This is the highest redshift galaxy-absorber pair detected to-date, supporting the idea that galaxy-wide outflows were already in place at the end of the epoch of reionization. The proximity of this object makes it the most likely source of metals, consistent with models of outflows at lower redshift where significant observational evidence relates metal absorption systems with galaxies hosting outflows. Moreover, we estimate that the probability of a closer, fainter galaxy being responsible for the absorption system is only ∼ 10 −3 .

Research paper thumbnail of At the heart of the matter: the origin of bulgeless dwarf galaxies and Dark Matter cores

For almost two decades the properties of "dwarf" galaxies have challenged the Cold Dark... more For almost two decades the properties of "dwarf" galaxies have challenged the Cold Dark Matter (CDM) paradigm of galaxy formation. Most observed dwarf galaxies consists of a rotating stellar disc embedded in a massive DM halo with a near constant-density core. Yet, models based on the CDM scenario invariably form galaxies with dense spheroidal stellar "bulges" and steep central DM

Research paper thumbnail of A galaxy as the source of a C iv absorption system close to the epoch of reionization★

Monthly Notices of the Royal Astronomical Society, 2011

A galaxy as the source of a C iv absorption system close to the epoch of reionization ⋆ ABSTRACT ... more A galaxy as the source of a C iv absorption system close to the epoch of reionization ⋆ ABSTRACT We find a bright (L UV = 2.5 L ⋆ z=6 ) Lyman alpha emitter (LAE) at redshift z = 5.719 at a projected distance of 79 physical kpc from a strong triply ionized carbon (C iv) absorption system at redshift z = 5.7238 previously reported in the spectrum of the z em = 6.309 QSO SDSS J1030+0524. This is the highest redshift galaxy-absorber pair detected to-date, supporting the idea that galaxy-wide outflows were already in place at the end of the epoch of reionization. The proximity of this object makes it the most likely source of metals, consistent with models of outflows at lower redshift where significant observational evidence relates metal absorption systems with galaxies hosting outflows. Moreover, we estimate that the probability of a closer, fainter galaxy being responsible for the absorption system is only ∼ 10 −3 .

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