Show simple item record

dc.contributor.authorGuillochon, James
dc.contributor.authorLoeb, Abraham
dc.date.accessioned2019-09-24T12:03:55Z
dc.date.issued2015
dc.identifier.citationGuillochon, James, and Abraham Loeb. 2015. “THE FASTEST UNBOUND STARS IN THE UNIVERSE.” The Astrophysical Journal 806 (1): 124. https://doi.org/10.1088/0004-637x/806/1/124.
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:41393203*
dc.description.abstractThe discovery of hypervelocity stars (HVSs) leaving our galaxy with speeds of nearly 10(3) km s(-1) has provided strong evidence of the existence of a massive compact object at the galaxy's center. HVSs ejected via the disruption of stellar binaries can occasionally yield a star with v(infinity) less than or similar to 10(4) km s(-1); here we show that this mechanism can be extended to massive black hole (MBH) mergers, where the secondary star is replaced by a MBH with mass M-2 greater than or similar to 10(5)M(circle dot). We find that stars that are originally bound to the secondary MBH are frequently ejected with v(infinity) > 10(4) km s(-1), and occasionally with velocities similar to 10(5) km s(-1) (one third the speed of light). For this reason we refer to stars ejected from these systems as "semi-relativistic" hypervelocity stars (SHSs). Bound to no galaxy, the velocities of these stars are so great that they can cross a significant fraction of the observable universe in the time since their ejection (several Gpc). We demonstrate that if a significant fraction of MBH mergers undergoes a phase in which their orbital eccentricity is greater than or similar to 0.5 and their periapse distance is tens of the primary's Schwarzschild radius, the space density of fast-moving (v(infinity) > 10(4) km s(-1)) SHSs may be as large as 10(3) Mpc(-3). Hundreds of SHSs will be giant stars that can be detected by future all-sky infrared surveys such as WFIRST or Euclid and proper motion surveys such as LSST, with spectroscopic follow-up being possible with the James Webb Space Telescope.
dc.language.isoen_US
dc.publisherAmerican Astronomical Society
dash.licenseLAA
dc.titleThe Fastest Unbound Stars in the Universe
dc.typeJournal Article
dc.description.versionVersion of Record
dc.relation.journalThe Astrophysical Journal
dash.depositing.authorLoeb, Abraham::9975df1f269ab49c1ad5a328a1ec1476::600
dc.date.available2019-09-24T12:03:55Z
dash.workflow.comments1Science Serial ID 100323
dc.identifier.doi10.1088/0004-637X/806/1/124
dash.source.volume806;1
dash.source.page124


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record