| Proposal ID | 055522 |
| Title | The baryon fraction in group-sized halos |
| Download Data Associated to the proposal | https://nxsa.esac.esa.int/nxsa-sl/servlet/data-action-aio?obsno=0555220101 |
| DOI | https://doi.org/10.5270/esa-uuxjco2 |
| Principal Investigator, PI | Dr Alastair Sanderson |
| Abstract | The baryon fraction (f_b) in collapsed massive halos has great cosmologicalsignificance, and comprises hot gas and stars --- both in galaxies and theintracluster light (ICL). While the gas mass is known to be depleted in groups,it is not clear if the missing baryons have been ejected from the halo or aresimply locked up in stars. The best current study suggests an increasing ICLfraction in groups offsets a declining gas fraction, implying a universal f_b,but this is based on only 2 low mass groups, with only estimated stellar baryonmasses. We propose to observe the only 4 poor groups for which astate-of-the-art measurement of intragroup stellar baryons has been made, to mapthe hot gas and thereby discriminate definitively between these two scenarios. |
| Publications |
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| Instrument | EMOS1, EMOS2, EPN, OM, RGS1, RGS2 |
| Temporal Coverage | 2008-08-02T03:38:55Z/2010-10-29T21:54:35Z |
| Version | 21.51_20241115_1113 |
| Mission Description | The European Space Agencys (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESAs second cornerstone of the Horizon 2000 Science Programme. It carries 3 high throughput X-ray telescopes with an unprecedented effective area, and an optical monitor, the first flown on a X-ray observatory. The large collecting area and ability to make long uninterrupted exposures provide highly sensitive observations. Since Earths atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists to solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself. Observing time on XMM-Newton is being made available to the scientific community, applying for observational periods on a competitive basis. |
| Creator Contact | https://www.cosmos.esa.int/web/xmm-newton/xmm-newton-helpdesk |
| Date Published | 2011-11-19T00:00:00Z |
| Last Update | 2026-07-09 |
| Keywords | "declining gas fraction", "thereby discriminate definitively", "cosmological significance", "art measurement", "hot gas", "icl fraction", "comprises hot gas", "universal f_b", "missing baryons", "sized halos", "simply locked", "gas mass", "collapsed massive halos", "baryon fraction f_b", "baryon fraction", "intragroup stellar baryons", "low mass", "intracluster light icl" |
| Publisher And Registrant | European Space Agency |
| Credit Guidelines | European Space Agency, Dr Alastair Sanderson, 2011, 'The baryon fraction in group-sized halos', 21.51_20241115_1113, European Space Agency, https://doi.org/10.5270/esa-uuxjco2 |
| Rights | Data hosted in the ESA Space Science Archives are distributed under the CC BY-NC 3.0 IGO license. |