| Proposal ID | 014519 |
| Title | Shadowing the Diffuse Extragalactic X-Ray Background |
| Download Data Associated to the proposal | https://nxsa.esac.esa.int/nxsa-sl/servlet/data-action-aio?obsno=0145190101 |
| DOI | https://doi.org/10.5270/esa-15fmbmf |
| Principal Investigator, PI | Prof Joel Bregman |
| Abstract | The majority of the baryons in the present-day universe are missing in thatthey are not in galaxies or as cool intergalactic gas (<1E5K). These baryons aremost likely diffuse gas at 1E6 - 1E7 K in regions of modest overdensity, and thesuperposition of many such regions can produce detectable X-ray emission thataccounts for about 10-30% of the X-ray background in the 0.2-1 keV range. Todetect this emission, we used the shadowing properties of the gas in the edge-ongalaxy NGC 891, and we find a shadow at the 99% confidence level, consistentwith a fraction of the XRB in a diffuse cosmic component. We propose additionalobservations of a better edge-on system, NGC 5907, to determine whether shadowsare universal and to better measure the level of this cosmic diffuse XRB. |
| Publications |
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| Instrument | EMOS1, EMOS2, EPN, OM, RGS1, RGS2 |
| Temporal Coverage | 2003-02-20T15:33:39Z/2003-03-01T04:17:31Z |
| Version | 17.56_20190403_1200 |
| 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 | 2004-03-16T00:00:00Z |
| Last Update | 2025-01-27 |
| Keywords | "diffuse cosmic component", "kev range", "shadowing properties", "ngc 5907", "diffuse gas", "modest overdensity", "cosmic diffuse xrb", "cool intergalactic gas", "detectable xray emission", "NGC 891", "confidence level", "galaxy ngc 891", "1e6 1e7", "xray background" |
| Publisher And Registrant | European Space Agency |
| Credit Guidelines | European Space Agency, Prof Joel Bregman, 2004, 'Shadowing the Diffuse Extragalactic X-Ray Background', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-15fmbmf |